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7786285
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Guanine nucleotide exchange factors: activators of the Ras superfamily of proteins.
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Ras proteins function as critical relay switches that regulate diverse signaling pathways between cell surface receptors and the nucleus. Over the past 2-3 years researchers have identified many components of these pathways that mediate Ras activation and effector function. Among these proteins are several guanine nucleotide exchange factors (GEFs), which are responsible for directly interacting with and activating Ras in response to extracellular stimuli. Analogous GEFs regulate Ras-related proteins that serve other diverse cellular functions. In particular, a growing family of proteins (Dbl homology proteins) has recently been identified, which may function as GEFs for the Rho family of Ras-related proteins. This review summarizes our current knowledge of the structure, biochemistry and biology of Ras and Rho family GEFs. Additionally, we describe mechanisms of GEF activation of Ras in signal transduction and address the potential that deregulated GEFs might contribute to malignant transformation through chronic Ras protein activation.
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7786286
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Determinants of blastomere identity in the early C. elegans embryo.
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Genetic and molecular studies of development in Caenorhabditis elegans have identified regulators that appear to control pattern formation in the cellularized nematode embryo. Two genes, skn-1 and pie-1, are required for specifying the different identities of two sister blastomeres in a 4-cell embryo, called P2 and EMS. The skn-1 gene encodes a DNA binding protein that may control blastomere development by regulating transcription in EMS and its descendants. ABa and ABp, the other two sisters in a 4-cell embryo, are influenced to develop differently by cell signaling events that require the two genes apx-1 and glp-1. In this review, I summarize evidence that some or all of these genes may encode embryonic determinants of blastomere identity.
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7786283
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Specifying the target identity of motoneurons.
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In the vertebrate spinal cord, motoneurons are clustered into longitudinal columns in agreement with the targets they innervate. Motoneurons within each column acquire properties early in development that ensure their axons navigate to appropriate targets, but how this target identity is specified is unknown. Recently, Tsuchida et al. described the expression of putative regulatory genes within motor columns in the chicken spinal cord. Combinations of LIM-family homeobox genes differentially mark columns that project to distinct target groups. Expression precedes column formation and axon outgrowth, making these genes candidates for specifying the target identity of motoneuron groups.
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7786284
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Precursor cell types in the germinal zone of the cerebral cortex.
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Retroviral lineage tracing experiments suggest that the cortical ventricular zone is composed of a mixture of precursor cell types. The majority generate a single cell type (neurones, astrocytes or oligodendrocytes) and the remainder generate neurones and a single type of glial cell. Pluripotential precursor cells, that have the ability to generate all three cell types, are not observed. A recent paper, however, reports that when single ventricular zone cells are cultured in isolation, a small percentage of these cells are pluripotential. This review will discuss what this knowledge tells us about cortical development.
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7786282
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[Intraosseous epidermoid cysts of the toe phalanx in dogs].
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Out of 1057 amputated canine toes with tumours, tumour-like or other lesions, 17 cases were histopathologically diagnosed as epidermoid cysts of the terminal phalanx (EP). They were accompanied by osteolysis, reactive bone formation and chronic inflammation of phalanx 3. Extension of reactive changes to the phalangeal joint and phalanx 2 was less frequent. Various breeds were involved. There was no breed predisposition. The average age was 10.8 years; the male-female ratio 2.4:1. Nine EP were located on the forelimbs, 4 on the hindlimbs. In 4 cases location was unknown. Toes 4 and 5 were most frequently affected. A traumatic origin is suspected.
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7786281
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[Elevation of 7-dehydrocholesterol concentrations in serum and liver and pericentral peroxisome proliferation in hepatocytes of rats after inhibition of cholesterol biosynthesis by BM 15,766].
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Sprague-Dawley rats of both sexes were treated for three months with BM 15,766, an inhibitor of cholesterol biosynthesis in conjunction with standard or high-fat and high-cholesterol diets. In serum and livers of all drug-treated rats lowered cholesterol concentration associated with an increase of 7-dehydrocholesterol (7-DHC) was found. Electron microscopy of the liver showed a distinct proliferation of peroxisomes and an increase of dumb-bell shaped mitochondria in the pericentral zone 3. Abnormal-shaped peroxisomes with DAB-negative loops attached to their membranes were found in the intermediate zone 2. These alterations were more accentuated in drug-treated rats fed standard diet, then in treated rats receiving a high-fat and high-cholesterol diet. The observations demonstrate, that the increase of 7-DHC is due to the inhibition of 7-DHC-delta 7-reductase by BM 15.766 and emphasize the zonal heterogeneity of hepatocytes. The relevance of these observations for the investigation of the human Smith-Lemli-Opitz syndrome, in which also decreased plasma-cholesterol levels and an increase of 7-DHC were reported, is discussed.
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7786279
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[The significance of FeLV infection for diseases in necropsied cats].
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Persistent FeLV infection was demonstrated in more than 3000 necropsied cats by an immunohistological method. The findings were associated with the diagnoses established by means of post-mortem examination, histopathological, bacteriological, virological, and parasitological investigations. Statistically significant differences between FeLV-positive and FeLV-negative cats in the relative risk for certain lesions could be demonstrated for the first time. As a consequence, the importance of FeLV infection for the development of certain lesions in cats is to be seen under new aspects for some diagnoses. The relative risk for development of anemia, e.g., is only slightly increased in FeLV-positive animals whereas the relative risk for focal myocardial necrosis and coccidiosis is elevated tremendously in these cats. The relative risk for some lesions and diagnoses is much higher in FeLV-negative cats than in FeLV-positive animals. This is true, e.g., for myocardiopathy and hemorrhagic cystitis.
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7786280
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[Pulmonary emboli of skin and hair particles after intravenous injections].
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Among 1422 Sprague-Dawley rats treated daily for 28 consecutive days by i.v. injections, 779 animals (55.8%) showed lesions at the site of injection. 381 rats (26.8%) had pulmonary emboli with fragments of hair or skin in arterial thrombi or in giant cell granulomas. 6 weeks after cessation of treatment lesions were still found in lungs from 5 of 90 rats (5.6%) allowed to recover. In 8 of 64 Himalayan rabbits (12.5%) given 28 injections into ear veins pulmonary embolism was observed. Among 184 rhesus and cynomolgus monkeys treated daily for 28 consecutive days by injection into cephalic or saphenous veins, 167 monkeys (91%) showed lesions at the site of injection, 14 animals (7.6%) had pulmonary emboli with fragments of hair and skin in arterial thrombi or giant cell granulomas.
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7786278
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[Clostridium bifermentans infection in grass carp (Ctenopharyngodon idella)].
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The outbreak of an infection with Clostridium bifermentans in grass carp (Ctenopharyngodon idella) from a polyculture fish pond is documented.
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7786277
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[Detection of distemper virus N protein RNA in the brain of dogs with spontaneous distemper encephalitis using a digoxigenin-labeled, double-stranded DNA probe for in situ hybridization].
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A digoxigenin-labelled dsDNA-probe of 287 basepairs length complementary to the nucleoprotein-gene of canine distemper virus (CDV) was generated by the polymerase-chain-reaction. The dsDNA-probe hybridized specifically with base sequences of 8 different CDV strains, whereas no hybridization was observed with a porpoise and a canine parainfluenza virus and only a weak signal was obtained with measles virus. In formalin-fixed, paraffin-embedded brain sections of 35 immunohistologically CDV antigen positive dogs with spontaneous distemper encephalitis CDV-RNA could be detected in 25 cases by in situ hybridization. The reason for the lack of RNA detection in some immunohistologically positive dogs may be due to the low stability of DNA-RNA-hybrids. Degradation of RNA by RNAses or diffusion out of autolysed cells can not be excluded.
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7786275
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[Mammary carcinoma in female dogs: a new routine diagnosis by the detection of occult micrometastases in the regional lymph nodes].
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It was here to find an antibody staining either the epithelial tissues of the canine mammary or the tumor cell embolisms and metastases in their regional lymph nodes. 77 formalin-fixed and paraffin-embedded mammary carcinomas and their regional lymph nodes were examined by immunocytochemical technique, all of them free of metastases in routine haematoxylin and eosin (HE) staining. To compare the two methods two serial sections were cut of three parts of the lymph nodes. One was stained with the antibody AE1, which reacts with cytokeratin subtype I/A, in the SEQUENZA by APAAP-method, the other with HE. In 84.4% of all 77 lymph nodes tumour cell embolism and/or micrometastases were detected. Comparing the two methods we found that in HE-staining it was only possible to detect two thirds of all micrometastases containing more than 50 tumor cells. Smaller micrometastases were suspicious in a few cases, the majority could not be detected at all.
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7786276
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[Two mesenchymal tumor cell lines for the determination of natural killer (NK) cell activity in the peripheral blood of dogs].
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The two mesenchymal cell lines K1 and K6 were established from round cell tumours located at the lips of two dogs. Both cell lines were characterized as being of myelomonocytic origin by morphological, cytochemical, immunocytochemical and functional criteria. In the 51chromium release assay (effector/target cell ratio 100/1) the K6-cell line revealed a mean cytotoxic sensitivity of 53.6% and thus showed a susceptibility similar to that of the epithelial CTAC line (57.8%). The K1-cell line exhibited less cytotoxic activity (41%) when incubated for 14 h, but showed results comparable to the K6-cell line, when the incubation time was reduced to 8 h.
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7786274
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Endoscopic treatment of a giant ileal conduit calculus.
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A giant ileal conduit calculus is an uncommon complication of urinary diversion, with few recent reports present in the English literature. To date all described instances have necessitated treatment by laparotomy. The first reported successful management of such a condition by purely endoscopic means is reported.
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7786273
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Intracranial invasion from a primary adenocarcinoma arising in the middle and external ear.
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Cerumenal adenocarcinoma is a rare neoplasm arising from the modified sweat glands of the ear. Before the diagnosis of primary tumour is made, a thorough search must be undertaken to exclude the possibility of metastatic disease, which occurs more commonly. Benign adenoma can also occur and this may be identical histologically to the malignant variety. The presence of local invasiveness may be the only differentiating feature. Aggressive local resection followed by postoperative radiotherapy form the cornerstone of management. Individuals treated with radiotherapy alone have a life expectancy of less than 12 months whereas cures have been reported with radical surgery.
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7786272
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Sporting 'groin strains': not always muscular!
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A gluteal artery pseudoaneurysm presenting as a 'groin strain' following minor trauma is reported. Diagnosis was made by CT scan and arteriography. Treatment was with superselective catheterization and microcoil embolization.
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7786271
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Severe bronchospasm during rectal carcinoid resection.
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The manifestations of carcinoid syndrome result from a variety of hormones secreted by the carcinoid tumour. The minority of patients with carcinoid tumour suffer bronchospasm and flushing. In this report the possibility of carcinoid syndrome in a patient who developed severe bronchospasm during operative manipulation of his rectal carcinoid is discussed.
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7786268
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Video-assisted thoracoscopic lobectomy: a word of caution.
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Advances in video-assisted thoracoscopic (VAT) surgery allow it to assume an increasingly important therapeutic role. Two successful VAT lobectomies (left upper lobe and right lower lobe) were performed in patients with stage I adenocarcinoma. An 8 cm access minithoracotomy for hilar dissection and subsequent specimen delivery was used. Routine mediastinal node sampling was performed thoracoscopically as would be done conventionally. Video-assisted thoracoscopic lobectomy of the right upper lobe was attempted in another patient but he required emergency conversion to open thoracotomy because of bleeding from mechanical failure of the vascular staple-cutter. Although VAT lobectomy is feasible technically, attention to detail is important when mechanical devices are used to minimize the chance of malfunctioning. Once disaster occurs the surgeon should be capable of dealing with the consequences.
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7786267
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Morbidity and mortality after abdominal aortic surgery in a population of patients with high cardiovascular risk.
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Postoperative myocardial infarction is a major risk factor in patients undergoing abdominal aortic surgery. Correction of cardiac ischaemia prior to abdominal aortic surgery improves outcome. The morbidity and mortality of 639 consecutive patients were reviewed from an area with poor access to cardiac surgery, operated upon in a single tertiary referral hospital for aortic aneurysm or aortobifemoral grafting. A total of 101 patients with ruptured aortic aneurysm who survived to reach the intensive care unit experienced a hospital mortality of 29%. Multiorgan failure was the cause of death in 48% and postoperative myocardial infarction in 31%. Of the 253 patients with intact aortic aneurysm, which included elective and urgent resection, the mortality was 9%. There was a high incidence of uncorrected pre-operative ischaemic heart disease and myocardial infarction was the major cause of death (62%). Pre-operative myocardial infarction was predictive of postoperative cardiac morbidity and mortality. Of the 285 patients undergoing aortobifemoral grafting the mortality was 3% despite a high incidence of pre-operative ischaemic heart disease. Further reductions in postoperative death from ruptured aortic aneurysm must await improved screening to diagnose and treat the aneurysm before rupture. In patients operated upon electively, improved pre-operative cardiac screening and coronary bypass grafting where appropriate, especially for patients with aortic aneurysm and previous myocardial infarction, may further reduce peri-operative mortality.
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7786266
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V-Y advancement hamstring myocutaneous island flap repair of ischial pressure ulcers.
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Thirty-seven ischial pressure ulcers were repaired in 27 patients (eight quadriplegic, 19 paraplegic) between 1988-1993 using the V-Y advancement hamstring myocutaneous island flap. Twenty-one ulcers (57%) arose de novo and 16 were recurrent, with five patients having bilateral ulcers. The average duration of the ulcer was 5 months (range 1-30). All ulcers extended through the deep fascia (clinical grade IV), with the average diameter being 4.7 cm (range 2-10). There were four major flap complications (11%). All but one of the ulcers healed at discharge (97%). Mean follow up was 20 months (range 5-54) in 21 patients (78%), with six patients being lost to follow up. Seven of the 21 (33%) patients developed recurrent ulcers, with four of these having flap re-advancement with successful healing, and one patient having two re-advancements. Overall, 18 of the 21 (86%) patients with follow up had healed ulcers at time of follow up. The V-Y advancement hamstring myocutaneous island flap is versatile, reliable, easy to perform, has few complications, and can be re-advanced in the event of recurrence.
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7786265
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Limb length discrepancy in congenital talipes equinovarus.
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A retrospective analysis was performed to establish the prevalence and clinical significance of limb length discrepancy in congenital talipes equinovarus. Of 536 patients with the diagnosis of congenital talipes equinovarus, 259 were unilaterally affected and 277 bilaterally affected. Fifty-eight patients were identified with limb length discrepancy greater than 0.5 cm. Forty-six patients had unilateral foot deformity and in 12 cases that was bilateral. This represented a prevalence of documented limb length discrepancy in 18% of unilateral cases and 4% of bilateral cases. The discrepancy resulted in a surgical procedure to equalize the limb lengths in fourteen unilateral cases (5%). A further six unilateral cases were deemed likely to require limb length equalization, increasing the rate to 8%. Only three bilateral cases required or will require surgery for equalization (1%). There was a weak but significant correlation between the number of operations undergone and the magnitude of discrepancy. The tibia was as important in its contribution to the shortening in these patients as the foot. A total of 89% unilateral cases studied had at least 0.3 cm of tibial shortening and 43% had ipsilateral femoral shortening of at least 0.3 cm.
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7786263
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99mTechnetium labelled leucocyte scanning in acute lower abdominal pain: can it reduce the negative appendectomy rate?
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While the incidence of 'negative' appendectomy has long been justified as a necessary evil in the management of acute appendicitis, attempts to improve diagnostic accuracy have met with mixed results. In a prospective study of 34 selected patients who presented with acute lower abdominal pain the potential role of 99mTechnetium labelled leucocyte scanning in the diagnosis of acute appendicitis has been evaluated. Patient management was not based on the result of the nuclear scan. The clinical outcome was correlated with the scan diagnosis. There was one false positive and one false negative scan result with respect to the clinical diagnosis of appendicitis yielding a sensitivity of 90% and a specificity of 96%. 99mTechnetium labelled leucocyte scanning may have an important role in the assessment of selected patients presenting with acute lower abdominal pain.
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7786264
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A comparative study of two types of latex surgical gloves in elective orthopaedic surgery.
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Glove perforation during surgery represents a potential risk of infection for the surgeon. The authors postulated that thicker latex gloves may offer greater protection. The perforation rates for the Ansell Gammex glove and the thicker Baxter Triflex gloves were compared in single- and double-glove usage and no difference was found between the two brands, in either usage. The authors recommend double-gloving for all orthopaedic operations with regular glove changes during major procedures.
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7786262
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The influence of other diseases upon the outcome of colorectal cancer patients.
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Little attention may be paid during follow up of colorectal cancer patients to other medical problems because the follow up is normally focused upon the diagnosis of recurrence and the detection of metachronous neoplasms. Attention directed at improving the medical condition of patients would be justified if it were shown that other diseases had a significant effect upon survival. Review of a selected consecutive series of 207 patients included collection of data about variables relating to demography, pathology, presentation, smoking, present and past health, performance, surgery, complications, length of stay, mortality, follow up and cause of death. Significance of relationships between medical and surgical problems and the outcome was determined by analyses of variation. Medical problems were present in 79% of patients; correlated with advancing age. Medical problems were not associated with complications, or with inpatient death. Previous cerebrovascular accident, dementia, limited mobility and increasing numbers of problems were associated with prolonged stay. Prolongation of stay, however, was related mainly to surgical complications. Smoking, which was present in 50% of patients, did not alter performance status, stage or substage, stay or survival significantly. Smoking and respiratory complications were associated significantly. Patients with heart or peripheral vascular disease had significantly poorer survival (P = 0.007) than those without those problems. Survival was reduced significantly for patients known to have diabetes, cardiovascular and cerebrovascular disease and limited mobility. Other malignant neoplasms were responsible for 18% of deaths which were unrelated to colorectal cancer. Residual or recurrent colorectal cancer had a more rapid adverse influence upon outcome than did medical problems.(ABSTRACT TRUNCATED AT 250 WORDS)
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7786259
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Hepatic artery chemotherapy for colorectal liver metastases.
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Fifty per cent of patients with colorectal cancer develop hepatic metastases but only a minority are candidates for potentially curative surgical resection. Hepatic artery chemotherapy (HAC) has been used to treat patients with non-resectable metastases confined to the liver. Although response rates to HAC have been shown to be higher than response rates to systemic chemotherapy, the advantage in terms of survival has been debated. Furthermore, HAC requires surgical catheter placement which adds to the cost and morbidity of treatment. There have now been eight prospective randomized trials of HAC vs intravenous chemotherapy and/or supportive therapy. The present paper analyses the results of these trials with particular reference to survival. Surgical morbidity, treatment-related toxicity and cost are also discussed.
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7786260
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Bone scanning in the multiply injured patient.
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A prospective study was undertaken to evaluate the role of radionuclide bone scanning in the management of patients with multiple injuries. During a 7 month period, 14 patients with multiple injuries underwent a bone scan in order to identify occult skeletal injuries. All of the patients had new injuries diagnosed. The majority of new injuries occurred either in a limb in which an injury had already been diagnosed at presentation, or in the chest. Such findings are consistent with previously published data. Infrequently, there was a change in management of the patients in this series following the bone scan.
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7786258
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The Royal Australasian College of Surgeons and trauma care.
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This presentation is an account of the involvement of the Royal Australasian College of Surgeons in trauma care over the past 25 years. In October 1969 a 3 day seminar was held at the College entitled 'The Management of Road Traffic Casualties'. This was in response to an increasing demand for the College to combat the devastating effects resulting from road traffic accidents. By the mid-60s road trauma in Australia and New Zealand, as seen in other fully motorized countries, had reached epidemic proportions. Those directly involved in the care of surgical emergencies were aware of the frequency and severity of road trauma which was striking all sections of the community. Unlike the USA, Australia was not troubled by a high incidence of penetrating injuries due to guns and knives.
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7786247
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A quantification of alcohol-related mortality in New Zealand.
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There are no published New Zealand (NZ) studies on alcohol drinking and total mortality, despite its importance to alcohol health policy. To estimate the proportion of NZ deaths caused or prevented by alcohol drinking. The proportion of current alcohol drinkers from recent NZ surveys, and pooled relative risks from a review of the international literature on alcohol and mortality, were used to calculate disease-specific population attributable risks. The number of deaths caused (or prevented) by alcohol were calculated for 1987 New Zealand deaths. Person-years of life lost (or saved) were calculated using recent NZ life tables. The association between alcohol and total mortality was related to age. Alcohol was estimated to have caused 3.0% of all deaths among 0-14 year olds and 20.1% of deaths among 15-34 year olds, mostly from road injuries. In contrast, alcohol was estimated to have prevented 0.5% of all deaths among 35-64 year olds and 3.4% of deaths among > or = 65 year olds due to its protective effect against coronary heart disease. For all age groups, alcohol was estimated to have prevented 1.5% of deaths. However, the number of person-years of life lost among ages less than 35 years was greater than those saved in the older age groups, so that alcohol was estimated to have caused the loss of 9525 person-years of life for all ages combined. The adverse effects of alcohol on total mortality are confined to age groups less than 35 years. Public health policy to minimise deaths from alcohol should be concentrated on this group.
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7786242
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A prospective study of screening upper gastrointestinal (GI) endoscopy prior to and after bone marrow transplantation (BMT).
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Upper gastrointestinal (GI) endoscopic abnormalities are common in symptomatic bone marrow transplant (BMT) recipients but the incidence of occult gastrointestinal disease in these patients is unknown. To examine the role of screening upper GI endoscopy before and after BMT. Endoscopy was performed routinely on allogeneic (n = 24) and autologous (n = 17) BMT patients before transplant and at 30 and 120 days after transplant. Twenty-one of 41 patients (51%) had an endoscopic abnormality on one or more occasions which necessitated a change in treatment. These abnormalities were present in ten of 41 (24%) pre-transplant endoscopies, ten of 32 (31%) endoscopies at day 30 after BMT, and in seven of 22 (32%) day 120 endoscopies. Abnormalities included mucosal erosions or ulcers n = 22 endoscopies), infections (n = 5) or previously undiagnosed GI graft-versus-host disease (n = 3). Mucosal erosions or ulcers were present in eight of 28 endoscopies despite regular anti ulcer drug therapy. Screening upper GI endoscopy before and after BMT is generally safe and detects a high yield of significant GI abnormalities. However, it remains to be demonstrated that treatment of these lesions will improve the clinical outcome in BMT recipients without GI symptoms.
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7786239
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Application of the Poincaré plot to heart rate variability: a new measure of functional status in heart failure.
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Conventional methods of quantifying heart rate variability using summary statistics have shown that decreased variability is associated with increased mortality in heart failure. However, many patients with heart failure have arrhythmias which make the 'raw' heart rate variability data less suitable for the use of summary statistical measures. To examine the clinical potential of a new measure of heart rate variability data, presented by the Poincaré plot pattern, as an adjunct to the summary statistical measures of R-R interval variability. We used the Poincaré plot pattern to display beat-to-beat heart rate variability data from a group of 23 patients with heart failure and compared them with data collected from 20 healthy age-matched control subjects. The data, which consists of 2000 consecutive R-R intervals, were gathered over 20-40 minutes while the subjects rested supine in a quiet darkened room. The morphological classification scheme proposed reflected the functional status of patients in heart failure. There was a significant difference (chi-square = 27.5, p < 0.0001) in the different pattern types between patients with NYHA Class I and II compared to patients with NYHA Class II and IV. All healthy subjects displayed a 'cluster' type of pattern characterised by normally distributed data. Sixteen of the 23 patients in heart failure also produced data which were normally distributed but the remaining seven produced data which required careful filtering to make them suitable for analysis using summary statistics, but which could be analysed by the Poincaré plot. The Poincaré plot pattern is a semi-quantitative tool which can be applied to the analysis of R-R interval data. It has potential advantages in that it allows assessment of data which are grossly non-Gaussian in distribution, and is a simple and easily implemented method which can be used in a clinical setting to augment the standard electrocardiogram to provide 'real time' visualisation of data.
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7786240
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Comparative hospitalisation and mortality rates of aboriginal and non-aboriginal Western Australians in their sixth and seventh decades.
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Aboriginals have higher hospitalisation and mortality rates and die, on average, about 15 years earlier than non-Aboriginals in Western Australia (WA). To investigate Aboriginal morbidity and mortality rates in WA in comparison with the rest of the population, with particular reference to the ages of 50 to 65 years. Mortality rates from 1983-1989 inclusive for Aboriginals and non-Aboriginals in WA were compared. Major causes of Aboriginal mortality in males and females were matched to the ages at which similar rates from the same causes occurred in non-Aboriginals. Rate ratios (Aboriginal:non-Aboriginal) for causes of death at ages 60-64 years were determined. Hospitalisation rates for Aboriginal and non-Aboriginal people aged 50-64 years in WA in 1988 were used to estimate hospitalisation rate ratios. Hospitalisation rates in WA were much higher among 50 to 64 year old Aboriginals than non-Aboriginals for most diseases, particularly for infectious and parasitic diseases, and injury and poisoning. Admissions for circulatory diseases were double to four times as frequent among Aboriginals. The main causes of deaths in Aboriginal males were circulatory diseases, injury and poisoning, respiratory diseases, neoplasms, and digestive diseases; in Aboriginal females the main causes of deaths were circulatory diseases, neoplasms, diabetes, respiratory diseases, and injury and poisoning. Except for neoplasms, deaths from these causes occurred among 50-54 year old Aboriginals at rates that were experienced by non-Aboriginal people ten to 30 years later in life. These results underline special needs of the Aboriginal population that have not been adequately met by appropriate services.
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7786238
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Smoking-related beliefs and behaviour among adults with asthma in a representative population sample.
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Smoking and exposure to environmental tobacco smoke are inadvisable for adults with asthma. To determine the smoking prevalence and daily smoking rate of asthmatics and compare smoking-related beliefs and behaviours among smokers with and without asthma. To compare beliefs of asthmatics about passive smoking and asthma, how many are exposed at home and what they do when they are exposed, with people who do not have asthma. A representative population survey of 3019 South Australian adults aged 15 years and older interviewed in their own homes in late 1992. Twenty-eight per cent of asthmatics were smokers; mean daily smoking rate was 17.6. Asthmatics had similar patterns of smoking, readiness to quit and quit attempt histories as people without asthma. More than 40% of smokers with asthma did not perceive that smoking had greatly affected their health, over half did not believe they were at risk in future and two-thirds did not think future health problems would be serious. Among non-smokers, despite being more convinced of the effects of passive smoking on asthma, and being more concerned about exposure, those with asthma were no more likely to take protective action in response to actual or imminent exposure than those without asthma. One in ten non-smokers with asthma were exposed to smoking at home. The smoking habits of adults with asthma are cause for concern, with many asthmatic smokers perceiving they are not personally at risk from their smoking. Health education principles should be used by health professionals caring for asthmatic smokers to guide the selection and delivery of smoking cessation strategies. Prevailing restrictions on indoor smoking play an important role in protecting the respiratory health of non-smokers with asthma.
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7786237
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A questionnaire survey of dentists regarding knowledge and perceived competence in resuscitation and occurrence of resuscitation emergencies.
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Little information has been published on the knowledge and perceived competence of dentists in resuscitation or the occurrence of resuscitation emergencies in dental practice. Further, no such surveys have been done in Australia. A postal survey was therefore devised and the names of 350 dentists were randomly selected from the Australian Dental Association national membership registry. The response rate was approximately 45 per cent and the main results included: just under half of the respondents felt they were competent in basic resuscitation at the time of graduation, that is, in expired air resuscitation (EAR) and cardiopulmonary resuscitation (CPR); just less than two-thirds had undertaken resuscitation training since graduation; about three-quarters felt they would be able to perform EAR and almost two-thirds felt they would be able to perform CPR; almost 90 per cent gained a satisfactory score in a Resuscitation Quiz included in the survey; and just over 5 per cent had had to resuscitate a patient.
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7786236
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Oral Candida albicans from patients infected with the human immunodeficiency virus and characterization of a genetically distinct subgroup of Candida albicans.
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Candida albicans has been shown to vary in its phenotypic expression with the progression of human immunodeficiency virus (HIV) infection. This study was designed to investigate whether in Category IV HIV infected patients (CDC, Atlanta, USA) these phenotypic changes were related to changes in the genetic strain of the organism. Isolates of C. albicans were obtained from 45 patients with HIV infection during the progression of their disease as determined by percentage T4 lymphocyte count. Isolates were strain differentiated using two methods. In 67 per cent of the patients a single strain of C. albicans, as determined by the DNA analysis, was isolated from each individual over the experimental period. The phenotypic expression of the genetically identical strains isolated from each patient varied considerably over the experimental period with the morphotype 754 being predominant. These results showed that the genotype of C. albicans isolated persisted in the majority of HIV infected individuals, but that the phenotypical expression of this strain changed. A finding in this study was that 18 strains of C. albicans had DNA which did not hybridize to the probe used. These strains were analysed for the presence of two other C. albicans specific DNA segments using PCR. The probe 27A hybridizing strains yielded PCR products which differed from the non-hybridizing strains. Five of these genetically atypical C. albicans strains and 98 of the C. albicans strains were then analysed for purported virulence factors.(ABSTRACT TRUNCATED AT 250 WORDS)
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7786235
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The choice of irrigant during hand instrumentation and ultrasonic irrigation of the root canal: a scanning electron microscope study.
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The purpose of this study was to investigate the use of 4 per cent sodium hypochlorite and 15 per cent EDTAC, either alone or in conjunction, as irrigants during hand instrumentation and ultrasonic irrigation of the root canal. Thirty-six extracted human teeth, each with a single, straight root 21-25 mm long were hand-instrumented through a clinical access cavity to file size 40. One millilitre of the test irrigant was used after each instrument size. Canal debridement was completed with an intermittent flush irrigation technique with one or both of the test irrigants activated by ultrasound at a medium effective power output. The specimens were sectioned longitudinally, viewed in a scanning electron microscope and scored for the presence or absence of debris and smear layer at levels less than 1 mm, 5 mm, and 10 mm from the apical seat. Under the conditions of this experiment the most effective regime was irrigation with 1 mL EDTAC after each instrument size, followed by two 30 second exposures to ultrasound+EDTAC then four 30 second exposures to ultrasound + 4 per cent sodium hypochlorite. The specimens in this group were free from retained pulp tissue and superficial smear layer, had the lowest debris scores at the < 1 mm and 5 mm levels, and the lowest total debris score. All of the techniques tested produced smear-free canals at the 10 mm level.
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7786234
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A comparison of the effects of Nd:YAG and Ho:YAG laser irradiation on dentine and enamel.
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This preliminary study was undertaken to investigate the effects of Nd:YAG and Ho:YAG lasers on enamel and dentine of extracted teeth. The Ho:YAG laser (spot size 250 microns, energy density 4160 J/cm2) produced a cleaner puncture in dentine with less melting of the surrounding tissue than did the Nd:YAG laser (spot size 20 microns), energy density 50,000 J/cm2), which produced considerable melting and recrystallization of dentine and was more difficult to control. It was possible to cut enamel and dentine with both lasers, but considerable melted and recrystallized enamel was produced. From the limited observations of this study it appears that the Ho:YAG laser is more suitable for cutting both enamel and dentine than the Nd:YAG laser. More work needs to be done to ascertain the effect on enamel and dentine of modification of the parameters of both lasers.
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7786233
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Effects of splint therapy in TMJ dysfunction: a study using magnetic resonance imaging.
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This pilot study was undertaken to correlate clinical and MRI diagnoses in seven symptomatic TMJ dysfunction patients and to account, if possible, for the clinical improvement in the signs and symptoms after the use of a maxillary stabilizing splint. The symptomatic TMJs were evaluated by means of MRI prior to splint insertion. Sagittal open/closed, and coronal closed images were obtained with a 0.3 T Fonar MR Scanner. A follow-up MRI was taken after three months of splint therapy for the purposes of a comparative study. All subjects responded positively even at the early phase of splint treatment. By the end of the three month period, six subjects experienced full remission of pain in the TMJ and associated masticatory muscles with one subject experiencing only partial remission following therapy. Baseline MRI study revealed that only three subjects had anterior disc displacement while the other four subjects had normal disc/condyle relationships and morphology. In the follow-up MRI study, there were no signs of recapture of the three anteriorly displaced discs despite there being evidence of improved jaw movement and remission of pain symptoms. The use of MRI in this preliminary study indicates that some but not all TMJ pain dysfunction syndromes are caused by internal derangements of the joint. A larger MRI study using the same clinical parameters is indicated for future research.
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7786231
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Degradative enzymes of oral streptococci.
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Members of the Streptococcus sanguis group (SSG) and Streptococcus milleri group (SMG) were screened for their ability to produce glycosidase, arylamidase (peptidase), protease, dextranase and glycosyltransferase activities. Species within each group produced unique patterns of activity. The most commonly produced glycosidases were beta-D-glucosidase, beta-D-galactosidase, N-acetyl-beta-D-glucosaminidase and N-acetyl-beta-D-galactosaminidase and the least commonly produced glycosidase activity was beta-fucosidase with Streptococcus intermedius (SMG) being the only species capable of producing the activity. For arylamidase activity, the most commonly produced type was lysine-arylamidase. Glycosidase and arylamidase activities were localized to particular sub-cellular fractions. alpha-galactosidase was found only in culture supernatant fluids whereas N-acetyl-beta-D-glucosaminidase was found in all fractions; the culture supernatant, cell wall, cell membrane and cytoplasm. No arylamidase activity was seen in culture supernatants. Phe-arg-arylamidase was found only in cytoplasmic fractions whereas val-pro-argarylamidase was found in cell walls, cell membranes and cytoplasmic fraction. Protease activity was measured as the degradation of bovine serum albumin (BSA) and casein. Casein was degraded by a number of strains whereas no species/strains were able to degrade BSA. Streptococcus intermedius, Streptococcus constellatus (SMG), Streptococcus mitior and Streptococcus defectivus (SSG) were the only species that produced hyaluronidase and no species produced chondroitin sulphatase. The groups were also examined for their abilities to produce glycosyltransferase and dextranase. Strep. sanguis, Streptococcus gordonii, Streptococcus mitis and Streptococcus oralis produced glucosyltransferase and, with the exception of the latter species, fructosyltransferase. No species within the SMG was capable of producing either glycosyltransferase.(ABSTRACT TRUNCATED AT 250 WORDS)
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7786229
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Donor variability in the proliferation of human dental pulp fibroblasts.
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Fibroblasts were isolated from human dental pulps of healthy third molars from 49 donors of ages ranging from 17 to 68. Significant variability was noted in the success of obtaining primary cultures from these pulps. Variability between the various cultures was also observed in the reliability of maintaining subcultures of the primary cultures as well as recovery from frozen stocks of established cell lines. Of the original 49 explant cultures studied, only three survived long-term passage and freezing. In addition to difficulties and variability in establishing cell lines, the human pulp fibroblasts also showed great variability in proliferative activity which could not be accounted for by donor age, source, or passage number. These findings highlight significant difficulties in establishing reliable human pulp fibroblast cultures and the need for great care in interpreting any in vitro data.
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7786230
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Extrusion of root-filled incisors in beagles--a light microscope and scanning electron microscope investigation.
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The response of the periodontal ligament to orthodontic extrusion of the incisor of a beagle was examined with light microscope and scanning electron microscope techniques. The ligament morphology was slightly altered by the procedure but was essentially normal. Teeth that were extruded and retained for 12 weeks exhibited partial relapse. Where a full thickness mucogingival flap was raised and immediately replaced in lieu of retention, continued extrusion was observed. Root resorption was observed at the interproximal region of the cervical third in three out of five specimens. The resorption had been repaired with cellular cementum.
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7786228
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Genetic and environmental influences on facial profile.
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Observed variation in facial morphology results from the influences of both genetic and environmental factors. To investigate the role of genetic influences on variation in facial profile, lateral photographs of 23 male and 19 female monozygous (MZ), and 15 male and 22 female dizygous (DZ) twin pairs were selected from the records of the South Australian Twin Study. Soft tissue landmarks and facial profiles were identified, traced and digitized. Linear and angular measures defined by the landmarks were calculated and a series of Fourier functions derived to describe the facial profiles. These Fourier amplitudes were interpreted in terms of the specific regions which they represented. Correlations within MZ pairs were consistently higher than within DZ pairs for both the facial dimensions and the Fourier amplitudes, providing evidence of significant genetic contribution to facial convexity, facial height and facial depth. Variability in nose and lip morphology appeared to be under stronger environmental influence.
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7786227
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An eye for an eye. A simplified model for teaching.
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We developed an easily constructed, inexpensive eye model that consists of a Styrofoam head carved out to house a slide holder, a wide-angle, clinical photographic fundus slide, a plastic face, and an anatomically correct eye. The model can be used by students and residents to learn direct and indirect ophthalmoscopy, fundus photography, and laser photocoagulation. This model gives students and residents a realistic learning experience without inconveniencing or endangering patients.
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7786226
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Use of intravitreal autologous blood to identify posterior cortical vitreous in macular hole surgery.
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Surgical management of macular holes involves removal of tractional prefovial vitreous cortex. Accurately identifying this adherent tissue can potentially decrease intraoperative complications. A new, effective technique using autologous whole blood can be used to identify and facilitate separation of the posterior cortical vitreous.
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7786224
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Viability of human corneal endothelium following Optisol-GS storage.
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To evaluate endothelial viability of human corneas stored in glass vials and in viewing chambers (Alcon) for extended periods, and to compare endothelial viability of Optisol-GS-stored corneas with corneas excised from moist chamber-stored globes. Endothelial viability was assessed using two staining techniques. Endothelium from stored corneas was stained with trypan blue combined with alizarin red S or stained with calcein AM-ethidium homodimer. Both techniques were used to determine which method is a more sensitive indicator of cytotoxic change. Corneas stored 4 to 21 days in Optisol-GS had a rate (mean +/- SE) of endothelial cell damage of 0.57% +/- 0.30% per day in vials and 0.69% +/- 0.27% in chambers. After storage intervals from 4 to 21 days, the Optisol-GS endothelium had an average decrease in viability of 9.5% to 16%. The endothelium of moist chamber eyes had a 44% to 59% decrease in viability after 2 to 5 days. After 24 hours, corneal endothelium of moist chamber eyes had less than 15% decrease in viability. Optisol-GS corneas stored for 35 to 56 days had greater than 50% decrease in endothelial viability. After 67 days, 95% to 100% of endothelial viability was lost. Corneas stored in Optisol-GS through 21 days at 4 degrees C maintain a high percentage of viable endothelial cells. There was no significant difference of endothelial viability between corneas stored in glass vials or in viewing chambers (Alcon). A 50% loss of endothelial viability occurred in moist chamber-stored corneas after 2 days and by 35 days in corneas stored in Optisol-GS.
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7786223
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Retinoblastoma. Cell of origin.
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To apply modern techniques of molecular cell biology and to revisit the old question of the cell of origin for retinoblastoma in hopes of gaining a better understanding of the retinoblastoma gene's antioncogenic mechanisms. Twenty-two consecutively accessed retinoblastomas were examined with immunocytochemical techniques for numerous retinal proteins. Both single and double labeling were used. Enzyme histochemistry for carbonic anhydrase was used as well. Differentiated areas of the tumors contained abundant Müllerlike cells. Fleurettes stained mostly for red and green cone-specific antibodies while features of blue cones and rods predominated in areas with high cytoplasmic-to-nuclear ratios but no fleurettes. All of the differentiated neoplastic cells were either photoreceptors or Müller's cells. No other retinal cell types were found. The cells of retinoblastoma are capable only of bipotential differentiation, ie, Müller's cells and photoreceptors. Given this and recent findings concerning retinal embryogenesis, we argue for the rod photoreceptor as the cell of origin. A possible role for the retinoblastoma gene product is discussed.
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7786222
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Calcific phacolysis. Salvageable vision following treatment.
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Calcific phacolysis has been previously described histopathologically in the enucleated eyes of three patients with unilateral posttraumatic total blindness. Each eye showed dissolution of a mature cataractous lens with dispersion of calcific lens material throughout the globe. We studied a patient in whom the signs of calcific phacolysis developed 19 months following intraoperative dislocation of a cataract into the vitreous. Partial removal of calcific particles was achieved by subtotal vitrectomy and lensectomy, with subsequent penetrating keratoplasty. Corneal histopathological findings showed a deposition of calcified lens particles between Descemet's membrane and retrocorneal fibrous membrane. Despite diffuse retinal calcification, the patient's visual acuity was 20/400. To our knowledge, this is the first report of calcific phacolysis occurring after surgical dislocation of a cataract into the vitreous and wherein treatment resulted in some preservation of vision. Early diagnosis and aggressive therapy may improve the visual prognosis in this condition.
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7786220
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Prevalence of foveal lesions in type 1 and type 2 Usher's syndrome.
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To evaluate possible differences in the prevalence of clinically detectable foveal lesions between patients with type 1 and type 2 Usher's syndrome. Records of 48 patients with type 1 and 98 patients with type 2 Usher's syndrome were retrospectively evaluated for the presence of a foveal lesion. The age, gender, and racial distribution of patients were similar in the two subtypes. Two investigators reviewed fundus photographs from all patients and, when available, fluorescein angiograms. In the 48 patients with type 1 Usher's syndrome, 30 (62%) showed a clinically apparent atrophic- or cystic-appearing foveal lesion, whereas in the 98 patients with type 2 Usher's syndrome, 33 (34%) had either an atrophic- or a cystic-appearing foveal lesion. Logistic regression analysis showed that the probability of exhibiting a foveal lesion in both type 1 and type 2 Usher's syndrome increases with age and that patients with type 1 Usher's syndrome are more likely to have a foveal lesion than are patients with type 2 Usher's syndrome. Patients with type 1 Usher's syndrome show a greater probability of having either an atrophic- or cystic-appearing foveal lesion than do patients with type 2 Usher's syndrome. This higher prevalence of foveal lesions is consistent with a previous observation that the severity of visual acuity impairment with age is greater for patients with type 1 than type 2 Usher's syndrome. These data are useful in counseling such patients as to their prognosis for central visual function.
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7786221
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Epithelial inclusion cyst of the iris.
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We describe the clinical presentation, high-frequency ultrasound biomicroscopic characteristics, and pathologic findings associated with a conjunctival inclusion cyst within the iris. The patient had undergone an uncomplicated extracapsular cataract extraction with posterior chamber intraocular lens insertion 9 months prior to presenting with a progressively enlarging iris mass. A clinical examination revealed a solid-appearing white tumor within the midiris stroma, accompanied by limbal-conjunctival hyperemia and anterior chamber inflammation. Ultrasound biomicroscopy revealed an egg-shaped solid iris stromal tumor that displaced the pigment epithelium. The mass was composed of three concentric layers of different echogenicity: a moderately reflective mantle, a less reflective middle zone, and a hyperreflective core. Within 3 days of initiation of topical corticosteroid therapy (prednisolone acetate, 0.5 mg per drop four times daily), the tumor enlarged and induced a plasmoid aqueous and a hypopyon. Histopathologic study revealed a conjunctival inclusion cyst with evidence of acute and chronic inflammation. We have found that the diagnosis of epithelial inclusion cyst within the iris can be aided by an ultrasound evaluation. This case also suggests that it may be preferable to excise these tumors prior to topical corticosteroid treatment.
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7786219
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The incidence of corneal abnormalities in the Silicone Study. Silicone Study Report 7.
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To determine factors that were prognostic of corneal abnormalities in eyes following surgery for severe proliferative vitreoretinopathy. Subgroup analysis of the Silicone Study. Community and university-based ophthalmology clinics. Eyes with attached maculae at the 24-month follow-up examination that did not have a pre-existing corneal abnormality. Vitrectomy surgery with long-acting gas or silicone oil. Epithelial and/or stromal edema, corneal opacity and/or previous corneal transplant. The incidence of corneal abnormalities at 24 months was 27% and did not differ significantly between treatment groups. Prognostic factors were preoperative aphakia or pseudophakia (P = .003), preoperative iris neovascularization (P = .006), reoperation (P = .001), the absence of a fluid/gas exchange (P = .03), corneal touch by silicone oil (P = .02), and the presence of aqueous cells (P = .009) or aqueous flare (P = .08). In a multivariate analysis, independent prognostic factors were iris neovascularization (relative risk [RR] = 13.1), aphakia or pseudophakia (RR = 3.0), postoperative aqueous flare (RR = 5.4), and reoperations (RR = 3.4). Corneal abnormalities were correlated with poor visual acuity and hypotony (P < .001). To our knowledge, this is the first study to document that the incidence rates of corneal abnormalities are equivalent between oil and gas. The incidence of corneal abnormalities in gas-filled eyes was higher than expected, and remained high in oil-filled eyes, despite the use of an inferior iridectomy. Successful surgical repair of the retinal detachment with a single operation, and prevention and early management of corneal touch by silicone oil should help to prevent corneal abnormalities. If rubeosis iridis or severe aqueous flare is present, preoperative treatment with intense topical and possibly periocular steroids might reduce inflammation, which might mediate corneal damage.
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7786216
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The National Basketball Association eye injury study.
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To investigate the epidemiology of eye injuries sustained by professional basketball players in the National Basketball Association (NBA). A prospective study involving all NBA athletes who sustained eye injuries between February 1, 1992, and June 20, 1993, was conducted. Twenty-seven NBA team athletic trainers, physicians, and ophthalmologists were provided data forms to complete for any player examined for an eye injury. Practice and game exposures during the preseason, regular season, playoffs, and championships were included. Of the 1092 injuries sustained by NBA players during the 17-month period, 59 (5.4%) involved the eye and adnexa. Eighteen (30.5%) of the injuries occurred while the player was in the act of rebounding, and 16 (27.1%) while the player was on offense. The most common diagnoses included 30 abrasions or lacerations to the eyelid (50.9%), 17 contusions (edema and/or ecchymosis) to the eyelid or periorbital region (28.8%), and seven corneal abrasions (11.9%). There were three orbital fractures (5.1%). Most injuries were caused by fingers (35.6%) or elbows (28.8%). Nine players (15.3%) missed subsequent games because of their injury. Fifty-seven players (96.6%) were not wearing protective eyewear at the time of injury. The incidence of eye injuries in NBA players during the 17-month period was 1.44 per 1000 game exposures. Frequent physical contact in professional basketball players leaves them at great risk for sustaining eye injuries. To prevent these injuries, protective eyewear is recommended.
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7786218
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Keratoprosthesis with biocolonizable microporous fluorocarbon haptic. Preliminary results in a 24-patient study.
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Most complications of a keratoprosthesis occur at the tissue-to-implant interface. The ideal prosthesis would eliminate this interface by having the tissue actually grow into the supporting material. We present a prospective clinical human study of a novel biocolonizable keratoprosthesis in 24 eyes of 24 patients. To promote implant stability, the 9-mm-diameter haptic was fashioned using a custom-made microporous fluorocarbon with a 4-mm-diameter, 2.67-mm-long, central optic made of medical grade polymethylmethacrylate, giving a global visual field of 110 degrees to 130 degrees. Only bilaterally blind patients with untreatable corneal diseases were included in the study. The haptic was inserted into a lamellar pocket delaminated in the stroma, and the optic was positioned through a hole trephined in the central cornea. The average follow-up was 15.7 months (range, 4 to 28 months). The host corneal fibroblasts penetrated and proliferated into the peripheral microporous fluorocarbon and provided anchorage between the cornea and prosthesis. Seventeen patients (70.8%) had visual acuity improvements. Mean corrected final visual acuity was 20/100 (range, 20/30 to 20/400). Five anatomic failures occurred in the first 6 months (three extrusions, one dislocation of the optic, and one endophthalmitis). We had one case (4.1%) of treatable glaucoma. We successfully removed four of five retroprosthetic membranes that had occurred. No retinal detachment occurred. The biocompatible inert microporous polymer did not eliminate all mechanical complications associated with a keratoprosthesis.
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7786217
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Outcome of corneal grafting with donor tissue from eyes with primary choroidal melanomas. A retrospective cohort comparison.
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To determine if melanomas have occurred in the recipients of corneas from donor eyes with primary choroidal melanomas and to determine the success of corneal grafting with tissue taken from eyes with primary choroidal melanomas. Retrospective cohort comparison and follow-up patient questionnaire. A tertiary medical center in Rochester, Minn. In patients who received corneal transplants, we reviewed 47 consecutive corneas transplanted from donor eyes enucleated for choroidal melanomas and compared them with 47 corneal grafts from donor eyes without melanomas matched for recipient age (+/- 10 years), date of operation (+/- 12 months), corneal storage time (+/- 24 hours), and operation type. No melanomas occurred in either group over a mean follow-up of 5.4 years (range, 0.4 to 15 years). There was no significant difference between the two groups in corneal thickness and endothelial cell loss at 2 months and 1 year after transplantation and in the probability of a rejection episode. There is no evidence of tumor transmission by transplantation of corneas from donor eyes with primary choroidal melanomas. Corneas transplanted from donor eyes with primary choroidal melanomas have similar outcomes to corneas transplanted from donor eyes without melanomas.
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7786215
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Dietary fat and age-related maculopathy.
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To describe the relationship between type and level of fat in the diet and the prevalence of age-related maculopathy. Retrospective population-based study. Residents of Beaver Dam, Wis, between the ages of 45 and 84 years, participating in the Beaver Dam Eye Study and Nutritional Factors in Eye Disease Study. Presence and severity of age-related maculopathy were determined from masked grading of fundus photographs taken from 1988 through 1990. Diets in the past (1978 through 1980) were assessed retrospectively using a food frequency questionnaire during in-person home interviews. Persons with intake of saturated fat and cholesterol in the highest compared with the lowest quintile had 80% and 60% increased odds for early age-related maculopathy, respectively, after adjusting for age and intake of beer. These relationships were not influenced by adjusting for several other potential confounding variables (carotenoid intake, intake of vitamins C or E in supplements, smoking, body mass index, time spent outdoors in the summer, gender, and history of diabetes, hypertension, or cardiovascular disease). Odds ratios for late age-related maculopathy were in similar directions but were not statistically significant. High intake of saturated fat and cholesterol is associated with increased risk for early age-related maculopathy in the Beaver Dam population. This supports the hypothesis that atherosclerosis or its risk factors are related to age-related maculopathy. Confirmation of this finding in other populations and in prospective studies is needed.
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7786214
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Sudden visual loss associated with sexual activity.
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To characterize the ocular fundus findings of patients who suffered sudden visual loss associated with sexual activity. Case series. Outpatient ophthalmic practice. Six patients presented with a precipitous decrease in vision in one eye with no apparent predisposing factors. After obtaining a careful history, each patient revealed that he or she had been engaging in rigorous sexual activity immediately before experiencing the visual loss. Five of the six patients were followed up without intervention. One patient required prophylactic laser photocoagulation of a retinal tear to decrease the risk of retinal detachment. Six patients aged 24 to 53 years suffered sudden loss of vision secondary to intraretinal, preretinal, or vitreous hemorrhaging. Visual acuity in the affected eyes ranged from a mild decrease (20/40) to profound visual loss (counting fingers at 6 in). Five of the six patients were followed up for at least 1 month and showed spontaneous improvement in vision as the blood cleared. Those who returned for long-term follow-up enjoyed complete visual recovery without any sequelae. Sudden debilitating visual loss may occur during sexual activity from the rupture of retinal blood vessels in the macular region or from the development of vitreous bleeding from an induced retinal tear. The long-term prognosis after such hemorrhaging appears to be excellent, with good visual recovery occurring as the blood resorbs spontaneously.
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7786210
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Socioeconomics viewpoint: the need for an update of the clinical practice guideline on cataract.
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In June 1994, the Agency for Health Care Policy and Research (AHCPR), Washington, DC, called a meeting to hear opinions on the need for a reconstituted panel to revise the recently published clinical practice guideline Cataract in Adults: Management of Functional Impairment. The need and timing of a revision depend essentially on the answer to two questions: (1) Are there serious flaws in the previous panel's work that would necessitate a re-review? or (2) Is there new scientific information that can be critically assessed that would substantially alter the recommendations of the guideline? It is important to consider these questions with care because any revision is likely to be both costly and time-consuming.
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7786213
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Features of age-related macular degeneration in a black population. The Barbados Eye Study Group.
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To report on the frequency of features of age-related macular degeneration in a black population based on fundus photograph gradings. Population-based study. Barbados, West Indies. Residents of Barbados, selected by a random sample of Barbados-born citizens, aged 40 to 84 years. Gradings from 30 degrees stereoscopic macular photographs. Black participants (n = 3444) completed examinations at the study site and had gradable macular photographs in both eyes. Drusen larger than 63 microns occurred with comparable frequency in men and women. The frequency of small drusen decreased with age, while medium and large drusen were more common in older participants. Frequencies of all age-related macular degeneration-related characteristics were similar for men and women except for small drusen, which occurred more commonly in women. Confluent drusen and pigment atrophy also increased significantly with age. Exudative features occurred in 0.5% of the participants. This study provides population-based data on the frequency of features of age-related macular degeneration based on photographic gradings of a black population. Features of early age-related macular degeneration were common, but appeared at a lower frequency than has been reported for white populations. Exudative disease was infrequent, occurring in about one of 200 participants.
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7786212
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A comparison of topical diclofenac with prednisolone for postcataract inflammation.
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To compare diclofenac sodium with prednisolone acetate for the control of postoperative inflammation after cataract surgery. Fifty-two patients undergoing phacoemulsification with posterior chamber intraocular lens implantation were randomly assigned to receive either 0.1% diclofenac eye drops or 1% prednisolone eye drops as their postoperative anti-inflammatory medication. The patients were examined 1 day (baseline), 1 week, and 1 month after surgery. Postoperative inflammation was evaluated subjectively by slit-lamp assessment of cell and flare and objectively by measurement of cell and flare with a laser cell and flare meter. At each visit, there was no statistically significant difference in postoperative inflammation either by slit-lamp assessment or with the laser cell and flare meter for the two treatment groups. In the dosage used, diclofenac was as effective an anti-inflammatory agent for uncomplicated post-cataract inflammation as prednisolone.
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7786211
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Teaching ophthalmology to primary care physicians. The Association of University Professors of Ophthalmology Education Committee.
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The evolution of our health care system toward managed care has placed primary care "gatekeeper" physicians in a position where they must examine and treat patients with diseases that are ordinarily treated by medical and surgical subspecialists. Many of these physicians may be poorly prepared to accept this new responsibility. The Association of University Professors of Ophthalmology (AUPO) has published a Policy Statement on Medical Student Education that suggests the minimum level of competence expected of general physicians when dealing with ophthalmologic problems. A recent survey of directors of residency programs in family practice, internal medicine, and pediatrics revealed that the training of primary care physicians (as opposed to academicians or subspecialists) has become a nearly universal programmatic goal. Most program directs believe that less than half of their residents meet the AUPO standard at the completion of medical school, and a significant minority do not meet the AUPO standard at the completion of their residency. An overwhelming majority of program directors believe that additional training in ophthalmology and other subspecialties should be incorporated into the training programs of primary care physicians. Ophthalmologists and other subspecialists should develop programs at the medical student level directed toward the education of primary care physicians, and should participate in the training of primary care physicians, as well as their own subspecialty residents. In the future, the primary care physician must be considered part of the "eye care team." Enhancing the ophthalmologic education of primary care physicians is in the best interest of quality patient care.
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7786209
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The effectiveness initiative. I. Medical practice guidelines.
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We examined the impact of the "effectiveness initiative" and medical practice guidelines on the practice of ophthalmology. The effectiveness initiative asserts that much of current medical practice is unnecessary or harmful, too costly, and unresponsive to patient desires. It promotes more critical review of the medical literature, research on outcomes, and stringent practice guidelines. Whereas current practice guidelines are helpful in codifying accepted procedures, they tend to sanction interventions of unproved value. Future guidelines will probably reject unproved interventions, especially if they are expensive. Although such guidelines may limit physicians' freedom of choice, they may protect them against capricious malpractice claims and unreasonable patient expectations.
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7786196
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Cellular and molecular biology of aryl hydrocarbon (Ah) receptor-mediated gene expression.
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2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) and related compounds elicit diverse toxic and biochemical responses in laboratory animals and mammalian cells in culture. TCDD induces CYP1A1 gene expression and results of extensive research have delineated the molecular mechanism of this response. In target cells, TCDD initially binds to the aryl hydrocarbon (Ah) receptor which accumulates in the nucleus as an Ah-receptor:aryl hydrocarbon nuclear translocator (Arnt) protein heterodimeric complex. The nuclear Ah receptor complex acts as a ligand-induced transcription factor which binds to transacting genomic dioxin/xenobiotic responsive elements (DREs/XREs) located in the 5'-regulatory region upstream from the initiation start site and this interaction results in transactivation of gene transcription. DREs have been identified in several other genes which are induced by TCDD, including CYP1A2, aldehyde-3-dehydrogenase, NAD(P)H quinone oxidoreductase, and glutathione S transferase Ya and similar induction response pathways have been observed or proposed. However, TCDD and other Ah receptor agonists also inhibit expression of several genes and research in this laboratory has investigated inhibition of estrogen (E2)-induced genes including uterine epidermal growth factor, c-fos protooncogene, and the progesterone receptor, estrogen receptor (ER) and cathepsin D genes in human breast cancer cell lines. In MCF-7 human breast cancer cells, E2 induces cathepsin D gene expression and this is associated with formation of an ER/Sp1 complex at the sequence in the promoter region (-199/-165) of this gene. Within 30 min TCDD causes a rapid inhibition of E2-induced cathepsin D gene expression in MCF-7 cells. Moreover, using a series of synthetic oligonucleotides which include the wild-type ER/Sp1 and various mutants, it was shown by gel electromobility shift and transient transfection assays that the nuclear Ah receptor complex binds to an imperfect DRE located between the ER and Sp1 binding sequences. This interaction results in disruption of the ER/Sp1 complex and inhibition of E2-induced gene expression. These results illustrate that the nuclear Ah receptor complex also exhibits activity as a negative transcription factor via a mechanism which is similar to that reported for Ah receptor-mediated induction of gene expression.
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7786168
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OTC pharmaceuticals and genotoxicity testing: the paracetamol, anthraquinone, and griseofulvin cases.
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Genotoxic effects are hardly assessable in an exposed population but are generally considered to be serious due to their unpredictable effects on subsequent generations and to the link between genotoxicity and cancer. Lack of knowledge about a genotoxic/carcinogenic potential has to be stated for numerous compounds which are often in pharmaceutical use known for a long time. A thorough testing programme like it is done for new compounds is essential for such compounds that are not completely unsuspicious with respect to being reactive with macromolecules or that have the potential to generate reactive metabolites in the body. Paracetamol, anthraquinone-containing preparations, and griseofulvin are examples for pharmaceuticals that have been in use for a long time but for which genotoxicity testing revealed a possible deleterious potential only recently. The Federal Health Office/Federal Institute for Drugs and Medical Devices therefore imposed new studies upon companies marketing these compounds in the last years. These studies in part led to a more thorough description of possible adverse effects or even restrictions for use. Paracetamol exhibits a genotoxic potential in vitro and in vivo probably via indirect, cytotoxicity or enzyme inhibition-mediated effects. Further studies will have to clarify whether a threshold could be established and whether effects do not occur at therapeutic dose levels. Genotoxicity data on the mixed group of anthraquinones reveal positive and negative findings. Compounds such as lucidin, danthron, emodin supposedly have a genotoxic and carcinogenic potential. Further studies with anthraquinone-containing plant preparations will have to clarify the content and genotoxic activity of the preparations and the active ingredients. Lucidin- and danthron-containing preparations are currently no longer in use now whereas restrictions apply for other anthraquinone-containing laxatives. Griseofulvin is acknowledged in the meantime as an aneugen for somatic and germ cells. It is in vitro effective in concentrations that correspond to therapeutic plasma levels.
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7786167
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The safety assessment of over-the-counter (OTC) products.
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In recent years many compounds have become available as Over-The-Counter (OTC) medicine, for self-medication, which were originally marketed as prescription medicines only. This has been coupled with changes in the consumers' behaviour to self treatment and the governments commitment to restrict rising health costs. The safety and safe use of OTC products are important considerations for their wide distribution which is paralleled by diminishing medical supervision. OTC products were generally registered when toxicological requirements differed from the stringent guidelines of today, and their safety assessment thus often involves ongoing evaluation as new data become available. For this, human data must also be integrated for these assessments. However, in some areas, such as mutagenicity and carcinogenicity testing, human data are hardly obtainable and testing in animals or cells, is ultimately the only reliable source for extrapolation to man. Routine toxicological methods have mainly been developed for the assessment of new pharmaceutical entities and often provide 'yes/no' answers only. Data of such tests are, therefore, not directly applicable to the safety assessment of OTC products. Additional information on the kinetics in animal and man are indispensable for such extrapolation. On the other hand, modifications of original test protocols for the assessment of new formulations are indispensable. It was the aim of this workshop to discuss general approaches of safety assessments within the important new area of OTC products, as well as to present specific cases of recently arisen safety issues.
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7786165
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Developmental neurotoxicity of carbon monoxide.
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The results of recent studies dealing with behavioral and electrophysiological dysfunctions induced in rat offspring by prenatal exposure to relatively mild CO concentrations (75 and 150 ppm) have been reviewed in the present paper. In particular, gestational exposure to CO produced the following behavioral changes: (i) reduction in the minimum frequency of ultrasonic calls emitted by rat pups removed from their nest; (ii) decrease in ultrasonic responsiveness to a challenge dose of diazepam; (iii) alterations in the acquisition of an active avoidance task. The electrophysiological changes induced by prenatal CO in peripheral nervous system are as follows: (i) increase in time constants of sodium current inactivation; (ii) increase in the percentage of the maximum number of activatable sodium channels at the normal resting potential; (iii) negative shift of sodium current reversal potential. Moreover, results of ongoing researches on peripheral myelinogenesis in rats exposed to CO during gestation will be also summarized.
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7786162
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Prenatal exposure to marihuana and tobacco during infancy, early and middle childhood: effects and an attempt at synthesis.
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Both marihuana and cigarettes appear implicated, in a differential fashion, in the neurobehaviour of infants and children born to women who used these substances during pregnancy. In a low-risk upper middle class sample, marihuana use was associated, in the newborn, with mild withdrawal symptoms and some autonomic disruption of nervous system state regulation. However, between 6 months and 3 years of age no behavioural consequences of marihuana exposure (once confounding factors were controlled) were noted. At four years of age, although global tests of intelligence did not differentiate exposed from non-marihuana exposed children, verbal ability and memory were associated with in utero marihuana exposure. At five and six years of age these general areas were also noted to be associated with maternal cannabis use as was sustained attention. These areas of neurobehavior that appear affected by marihuana exposure during fetal development are ones that are consistent with the cognitive construct of 'executive functioning' which is thought to be a marker of prefrontal lobe functioning. Consistent with the observations derived from these children is that prefrontal functioning may not be apparent until approximately four years of age and that executive functioning is disassociated from measures of global intelligence. Exposure to cigarettes during pregnancy appears to be associated with neurobehavioural deficits in the auditory domain. In the newborn this is manifested by decreased responsivity to sound and altered auditory habituation. Between the ages of one and 11 years the performance on auditory related tasks (verbal memory, language, auditory processing) were consistently the domains that differentiated the cigarette exposed from the non exposed children. The possible role of the cholinergic mediated efferent auditory system is discussed. Also associated with in utero exposure to cigarettes were general cognitive performance and parental reports and objectively derived measures of impulsivity. The striking degree of consistency over the years lends strength to the interpretation that the observations in childhood have, at least as their partial etiology, the prenatal exposure to cigarettes. However, in interpreting the evidence presented it must be recognized that the alterations in the child's behaviour may well affect the parenting behaviour. This potential transactional interaction must remain an integral part of drawing conclusions about both marihuana and cigarette's effects.
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7786147
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[Electrocardiographic aspects of atrial fibrillations].
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The electrocardiographic analysis of atrial fibrillation is usually easy. However, some cases may be difficult to interpret: the organisation and voltage of the fibrillation waves can be very variable leading to appearances of atypical flutter in cases with large "f" waves or, conversely, in cases with low voltage fibrillation, to those of sinus mode dysfunction. The ventricular response may be slow: the conduction is usually delayed in the atrioventricular node where concealed conduction plays an important role in determining the ventricular response. Regular ventriculogrammes correspond to a junctional or ventricular escape rhythms. Aberrant conduction in the His-Purkinje system may sometimes be observed after long diastoles (phase 4 block) but often terminates short, preceded by long cycles (phase 3 block). It is usually easy to differentiate them from ventricular ectopics or preexcitation by careful examination and application of classical diagnostic criteria.
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7786146
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[Value of the exercise test in the study of arrhythmia].
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Exercise testing may be used to assess symptoms occurring on effort, to search for and evaluate arrhythmias or conduction defects, antiarrhythmic drugs, pacemakers or implantable cardioverter defibrillators. Interpretation of exercise testing is difficult because of the complexity of the factors in play. Exercise itself induces changes in myocardial metabolism and the autonomic nervous system, the nature and importance of which are influenced by the underlying cardiac disease and the presence of cardiac failure or myocardial ischaemia. This is particularly true when studying the behaviour of arrhythmias on effort, which depends on many parameters, in that they may appear or disappear during exercise, irrespective of their relationship to autonomic nervous system activation. The main problem lies in the interpretation of changes in the heart rate before the onset of an arrhythmia. The sinus rhythm is both a passive indicator of the vago-sympathetic equilibrium and one of the determining factor of the arrhythmia (relationship to the rate), but it is, itself, dependent on the presence of myocardial dysfunction, a source of arrhythmias, and its changes then become difficult to interpret. These reasons explain why exercise testing is certainly a valuable tool in assessing arrhythmias but the poor reproducibility, especially in the evaluation of ventricular arrhythmias, advises prudence in the interpretation of results.
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7786145
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[Hemiblocks: electrocardiographic diagnosis].
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Left hemiblocks or fascicular blocks are conduction defects which lead to asynchronous left ventricular activation. The classical diagnostic criteria must be respected, especially the degree of left axial deviation in complete forms. Other, less well-known criteria, which include the widening of the QRS complex opposite the myocardial walls showing delayed activation, seem very useful for making the diagnosis. The real diagnostic difficulties lie in incomplete forms because the inferior limits of axial deviation in this type of conduction defect are not known and clinical progression is usually the decisive factor. Precise understanding of the clinical signs of hemiblock is useful in clinical practice for the discussion of the significance of Q waves in the right precordial leads or for explaining sudden changes in QRS axis or amplitude.
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7786143
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[Mechanisms of action of class III anti-arrhythmia agents].
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Vaughan-Williams class III antiarrhythmic agents act mainly by prolonging the duration of the cardiac action potential and, thus, the refractory period. This effect may be obtained: 1) by increasing the inward sodium or calcium currents, which may lead to an intracellular calcium overload and induce a very proarrhythmic situation, or 2) by decreasing the outward potassium currents, the objective of the new class III antiarrhythmic drugs under development. They selectively block one or several potassium channels regulated by the membrane potential (transient outward current Ito, delayed rectifying current IK and rectifying inward current IK1). Under physiological conditions the blockade of potassium channels regulated by a ligand (for example, ATP-dependent) does not lead to a class III effect. Prolongation of ventricular repolarisation is accompanied by a slowing of the heart rate and a positive inotropic effect. It is attenuated by rapid rhythms and amplified by slow rhythms: this is the reverse frequency-dependent phenomenon. However, normal frequency dependence (or "use-dependence") has been reported with the ionic channel, this paradox apparently being related to the complexity of the relations between the relative contributions of the ionic currents of repolarisation and their modulation by the heart rate. The class III effect confers a proarrhythmic potential and may lead to torsades de pointes, favorised by bradycardia, hypokalaemia and hypomagnesaemia. Experimentally, it favorises early after depolarisations which are presumed to be the cellular trigger event. The comprehension of factors influencing the antiarrhythmic and proarrhythmic class III effects has led to the establishment of a pharmacological profile of the "ideal" drug conferring the least proarrhythmic risk and the best efficacy.
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7786144
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[Atrioventricular nodal tachycardia].
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The atrioventricular junction consists of the atrioventricular node and the bundle of His up to its division. All tachycardias arising in these structures or which depend on these structures for their sustenance are called "junctional". There are four main types. The first three correspond to reciprocating rhythms, nodal tachycardia, tachycardias using an accessory pathway with unidirectional retrograde conduction, and chronic reciprocating atrioventricular nodal tachycardia. All varieties of reciprocating atrioventricular nodal tachycardia have been well studied and their diagnosis is possible from the standard surface electrocardiogram from the position and morphology of the P' wave. They are accessible to radical treatment by radiofrequency ablation of the slow pathway or accessory pathway, when present. The definitive treatment of ectopic atrioventricular nodal tachycardia is not yet established and has to be considered case by case, this form of arrhythmia being rare.
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7786142
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[Ventricular fibrillation and defibrillation; electrophysiological bases and clinical applications].
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During sinus rhythm, the successive responses to the application of electrical stimuli of increasing intensity during the vulnerable period are cardiac stimulations followed by repetitive ventricular responses and then ventricular fibrillation. An impulse of even greater intensity is not followed by ventricular fibrillation (shock at the upper limit of vulnerability) suggesting that defibrillatory shock is effective only when it does not reinduce fibrillation. Two other hypotheses are also proposed in fibrillation, that of critical mass and that of extension of the refractory periods, in particular after biphasic shocks. Clinically, the measurement of the threshold of defibrillation is difficult as it is a random process which does not obey the all or nothing principle. Ideally, a graph of efficacy versus energy should be constructed but this is only possible under experimental conditions. The effects of different antiarrhythmic drugs have been studied in this manner; in general, the sodium channel blockers improve the energies of defibrillation.
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7786140
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[Subjectivity in the reading of scientific articles].
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With the examples of historical incoherencies in the diagnosis and treatment of myocardial infarction and pulmonary embolism, the author shows that it is not easy to be an objective reader of "good" scientific articles. Our neuropsychological mechanisms do not facilitate an "intelligent" attitude without the aid of affectivity. An unwanted thymotic component places the reader in an ambiguous position with respect to authority and reality. Though one can never know too much, it is difficult, alone, to maintain an intelligent curiosity. Some financial interests may awaken it. During his career, the physician has to navigate between two slightly contradictory necessities: changing his attitude with respect to new information, and according credence to his personal experience.
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7786141
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[Hidden electric phenomena].
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Concealed electrical phenomena are activations which penetrate the specialised tissue incompletely, which do not have a direct electrical effect but which usually affect the conduction of the following normal impulse. The phenomena are extremely common. They arise physiologically in the node of Aschoff Tawara and express the relationship between flutter waves and their propagation to the ventricle. Any extrasystole or ectopic rhythm may give rise to these phenomena and modify conduction in the anterograde or retrograde direction if the ectopic rhythm is ventricular, by slowing the rate but also, in some cases, by paradoxically improving it. In addition, some reciprocating nodal tachycardias are due to a concealed bundle of Kent invisible in sinus rhythm, the presence of which may be suspected by the ECG appearances of the reciprocating tachycardia (negative P wave in lead 1, phenomenon of delaying bundle branch block or simply the auriculogram after the ventriculogram.
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7786139
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[Critical analysis of scales of quality of life in cardiology; applications to cardiac insufficiency].
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Scales of quality of life have only recently been imposed in cardiology. Essentially an Anglosaxon invention, they have been used for evaluating most treatment of cardiac failure. The main qualities of a good quality of life questionnaire are its sensitivity, its reproducibility and its validity. The contents of the questionnaire, particularly the relationship between items concerning symptoms and those concerning the psychological aspects of the disease, have a great influence on the quality of results. The "Living with Heart Failure Questionnaire" of the University of Minnesota is the most validated questionnaire at present. As with most other methods of therapeutic assessment in cardiology, the most recently obtained results from large multicenter trials, seem to show a much smaller benefit of drugs reputed to be effective in this condition, with respect to the quality of life of patients. This justifies: the continuation of validation of these questionnaires, a reflection on the efficacy of classical management of these patients.
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7786138
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[Reading of the trials in cardiac insufficiency; therapeutic studies (phases II B and III)].
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The object of therapeutic trials in cardiac failure is to improve the quality of life by controlling the principal symptoms which are dyspnoea and tiredness on effort and to improve survival. A critical review of therapeutic trials in cardiac failure must examine whether these two objectives have been attained and if they are attained simultaneously. In some cases, there is symptomatic improvement but with decreased life expectancy whereas in others, survival is prolonged without adequate control of symptoms. A critical analysis should examine the pertinence of these criteria of efficacy, and confirm that the problem of survival has been assessed, that reliable data has been provided, that the study population is representative of the real population of the patients to be treated, and finally, that the experimental protocol is realistic, i.e. a prospective study with analysis of intention to treat.
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7786137
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[Reading of the trials in cardiac insufficiency; preliminary and experimental studies (phases I-II)].
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In addition to general consideration concerning the justification and methodology of therapeutic trials, the interpretation of the results of evaluation of new products in the field of cardiac failure poses a number of problems. In experimental studies in the animal, the choice of model of cardiac failure, the mode of evaluation of the parameters and the justification of the choice of dosage studied require particular attention. In preliminary clinical trials (Phases I and II), the choice and number of subjects, the dosage and methodology both for recensement and interpretation of data, are factors which influence the quality of the information obtained. When these studies have been completed, the decisions whether to develop the product and the recommended dosage have to be taken. The importance of these decisions justifies the extreme attention which has to be taken in the elaboration of these studies and in their interpretation.
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7786135
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[Nitric oxide, from vascular physiology to therapeutics].
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Nitric oxide (NO) synthesised by endothelial cells, plays a key role in the control of vascular tone. Its synthesis from L-arginine is assured by NO-synthase, the activity of which is dependent on intracellular calcium concentrations, which are themselves modulated by pharmacological (acetylcholine, serotonin, bradykinin...) or physical factors (shearing forces exerted by blood flow). NO acts by stimulating a soluble guanylate-cyclase of the smooth muscle cells in the vessel wall. Its vasodilator effect is therefore mediated by an increase in intracellular cyclic GMP concentration. The synthesis or liberation of NO by the endothelium may be decreased or abolished during many pathological processes (hypercholesterolaemia, atherosclerosis, systemic or pulmonary hypertension...). The significance of this abnormality of NO-mediated endothelium-dependent vasodilation in different pathological conditions has not been established. However, it is probably significant in view of the different properties of NO: vaso-relaxation, antiaggregant and inhibition of vascular smooth muscle growth. It is not yet known whether this abnormality is a cause or a consequence of the underlying disease. From the therapeutic point of view, NO is an active metabolite of nitrate derivatives, sodium nitroprussiate and molsidomine which therefore share the same mode of action as the so-called "endothelium-dependent" vasodilatoe agents. The inhalation of NO, which is increasingly used in neonatal and adult intensive care units, is an alternative therapeutic approach in many conditions associated with pulmonary hypertension.
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7786136
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[Reading of articles concerning treatment of acute phase of myocardial infarction].
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The number of articles concerning the treatment of acute myocardial infarction is large, and systematic analysis can improve the comprehension of their results. The object of this paper is to propose a method of classifying these articles with respect to their qualities and defects in order to orient workers towards the use of the most satisfactory articles for bibliographic purposes. The questions that have to be addressed are: what is the object of the study; is the instrument of measurement adapted to the objective of the study; which patients were studied; was the study performed with a double-blind protocol; what was the number of cases and does this number allow a valid response to the question; what was the plan of the study; what were the judgement criteria and what significance can be accorded to these criteria, and finally, what was the type of analysis, were there analyses of sub-groups, and if so, are the analyses pertinent. Based on examples in the literature, the authors justify why these questions should be asked and how the responses to these questions influence the judgement of a given article. In conclusion, the quality of therapeutic trials in acute myocardial infarction is very variable: systematic analysis allows them to be classified in a subjective scale of quality.
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7786134
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[Coronary angioplasty: methods of evaluation].
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Coronary angioplasty is sometimes thought to be insufficiently validated considering the considerable development it has undergone and its place in modern cardiological practice. Nevertheless, several randomised clinical trials comparing angioplasty with medical therapy in stable angina (ACME) and with surgical treatment in stable and unstable angina (RITA) have provided more scientific support for the technique. The serious perioperative complications have become rare, the limiting factor being restenosis which is responsible for a large number of clinical recurrences and the reappearance of documented myocardial ischaemia. It is therefore logical to make restenosis the first objective of evaluation of PTCA. There are two possible approaches to this problem. The first relies on automatic quantitative operator-independent angiography as a gold standard. However, this method is methodologically complex, technically fastidious and only takes into consideration the anatomical appearances, the correlations with clinical outcome and prognosis of which are poor. It allows measurement of the amplitude of the process which is an unquestionable advantage, but it is only a partial view of the problem. The second method considers that only stenosis causing ischaemia is significant and that the criterion of evaluation should be the rate of new events and that the necessity of repeated attempts at revascularisation is the criterion of failure of the method. This overlooks the possibility of an anti-restenosis drug producing clinical results independents of its anatomical effect. Both methods have their advantages and drawbacks, which necessitates using them both in all trials of new tools or new molecules designed to prevent restenosis.
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7786133
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[Should substitution criteria be used in hypertensive disease?].
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A number of methods, some of which are still in the development phase, enable progressively more accurate assessment of structural and/or functional changes of the target organs of hypertension. The notion that these changes may be used as a substitution criterion in the evaluation of hypertensive disease is at the heart of the concept of preclinical cardiovascular disease: in its theoretical and practical aspects, this concept stipulates that the preclinical disease is an intermediate stage between exposure to the risk factor of hypertension and the advant of morbid or mortal cardiovascular events, and it suggests that the evaluation of the preclinical disease leads to a more accurate stratification of cardiovascular risk than measurement of the risk factors alone. However, at present, none of the parameters proposed (albuminuria, left ventricular mass, arterial wall thickness) is a validated substitution criterion; but many arguments indicate that the use of these parameters as intermediate criteria is justified under certain conditions.
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7786132
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[Reflections on therapeutic trials].
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The approach of establishing a relationship between cause and effect is a form of research contrary to the empirism which characterises many therapeutic trials. This empirism may result in certain embarrassing situations when the criteria of evaluation do not turn out to have the value that simple correlations attribute to them. Evaluating the efficacy of a drug whilst ignoring its mechanisms of action is courting danger, especially that of being unable to pursue a line of research when the global results are known in advance. These phenomena, observed in the example of the prevention of sudden death by antiarrhythmic drugs and betablockers, have the effect of impeding research in this complex field and the development of new and potentially useful drugs. It has become necessary to reevaluate the rules of medical experimentation which, in some cases, have reached the limits of feasibility and efficacy.
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7786131
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[Meta-analysis of clinical trials: values and limitations].
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Meta-analysis produces reproductible, qualitative as well as quantitative overviews of available evidence. Such a synthesis is a compulsory step in conveying information on therapeutics to health care providers. Compared to more traditional approaches, meta-analysis has enough advantages to make them no longer relevant. Its limitations come from inappropriate use or less than required rigorous application of its methodology.
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7786127
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[Surgical treatment of atrial fibrillation].
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The persistence of atrial fibrillation with a controlled ventricular response with medical treatment or ablation of the His bundle, suppresses troublesome palpitations but leaves potential haemodynamic problems and the risk of thromboembolism. Surgical treatment of this arrhythmia, by leaving an anatomic bridge between the sinus and atrioventricular nodes, aims to allow acceleration of the ventricular rhythm on exercise whilst preventing by partial, total or selective exclusion of atrial tissues, the multiple intra-atrial reentries responsible for atrial flutter or fibrillation. The first method proposed was isolation of the left atrium (Cox, 1980) which allows acceleration of the ventricular rhythm during exercise, leaving little or no haemodynamic disturbance, but, in theory, the same risk of embolism. The second method, the "corridor" operation (Guiraudon, 1985) consists in isolating both atria, but significantly alters the haemodynamic efficacy without reducing the embolic risk, and hardly offers any advantage over ablation of the nodo-hisian pathway completed by implantation of a ventricular, rate responsive, pacemaker. The recently described "maze" procedure (Cox and Boineau, 1991) would seem to be more promising with judiciously chosen incisions (at the base of the atria, around the pulmonary veins, between the vena cavae, along the interatrial septum, etc.) and points of cryoablation in the region of the coronary sinus, allowing modulation of the ventricular response with activation of sufficient atrial tissue to prevent reentry and recurrence of atrial fibrillation without affecting haemodynamic efficacy. The results of this technique are encouraging in the hands of its inventors but require confirmation in larger series of patients.(ABSTRACT TRUNCATED AT 250 WORDS)
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7786128
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[Atrial defibrillator: dream or reality?].
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The experience acquired with the use of automatic ventricular cardiovertor-defibrillator led to the idea of developing an atrial device capable of automatically detecting and reducing atrial fibrillation. The large group of patients with paroxysmal atrial fibrillation not responding to pharmacological therapy makes this a particularly relevant question. The first problem is to define the need of this type of device. There is only one group of patients with resistant and/or poorly tolerated paroxysmal atrial fibrillation in whom non-pharmacological therapy is considered, for example ablation of the AV node with implantation of a pacemaker or surgery. The second problem concerns the technical feasibility of an atrial defibrillator with the difficulty related to the detection of the arrhythmia and atrial defibrillation. The recognition of atrial fibrillation may be envisaged from endocavitary signals with satisfactory specificity and sensitivity. The problems related to atrial defibrillation with low energy shocks have not yet been solved clinically, although experimental studies have given promising results. The possible dangers are dominated by a pro-arrhythmic effect and the risk of ventricular fibrillation, but they could be avoided by synchronizing the atrial shock with ventricular activation based on results also obtained in the animal. Before the dream becomes reality, trials are necessary to develop a safe and effective automatic device. Intermediary stages of evaluation of such a device could include a device activated by the physician.
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7786126
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[Can atrial fibrillation be managed without anti-arrhythmia drugs?].
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Antiarrhythmic drugs are widely used in atrial fibrillation. The demonstration of severe pro-arrhythmic effects in recent years has led to the reappraisal of their indications in this pathology. Antiarrhythmic agents have three roles: reduction of the fibrillation, maintenance of sinus rhythm and, in case of failure, control of the ventricular response. In the first indication, although intravenous injection of Class Ic antiarrhythmics is effective in 70% of cases, there is an alternative: electrical cardioversion, which is effective in 90% of cases with the transthoracic method when a certain number of technical conditions are respected. The success rate is even better with endocavitary defibrillation. Sinus rhythm is sustained in only 25% of patients at one year with placebo and in 50% of patients with antiarrhythmic therapy. The alternatives in this indication are few at present and consist in right atrial pacing in cases of vagal fibrillation and biatrial pacing for resynchronizing the activation of the two atriae when there is a major interatrial conduction defect. The control of the ventricular response, in cases of permanent atrial fibrillation, is usually reserved to digitalis, betablockers, amiodarone and some calcium antagonists. They are often inadequate and an alternative is radiofrequency catheter ablation of the atrioventricular node, which requires permanent ventricular pacing. In conclusion, there are a few alternatives to antiarrhythmic drug therapy in atrial fibrillation, but they are relatively ineffective in maintaining sinus rhythm.
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7786125
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[Paroxysmal atrial fibrillation: role of autonomic nervous system].
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The electrophysiological properties of the atrial cells (duration of action potential and refractory period, conduction speed) are differently influenced by vagal and catecholamine stimulation: the first favorising phenomena of macroreentry, the second abnormal automatism and induced activity. In the normal heart, vagal tone is dominant at atrial level explaining that the clinical entity of paroxysmal vagal atrial fibrillation is observed in the absence of detectable cardiac disease in relatively young men with ECG appearances of alternating atrial flutter and fibrillation. Catecholamine-induced atrial fibrillation is usually observed with underlying cardiac disease. Besides the clinical terrain and appearances, the observation of the circumstances surrounding the triggering of atrial fibrillation and the features of the sinus rhythm and its variability before the induction of the episodes are the main factors which demonstrate the modalities of the influence of the autonomic nervous system. In cases resistant to treatment, the knowledge of these factors provides a guide to treatment, indicating which antiarrhythmic agents are poorly adapted or even harmful.
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7786124
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[Value of electrophysiological studies in the evaluation of atrial fibrillation].
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Electrophysiological studies of the atrium provide a means of evaluating the parameter involved in the process of fibrillation. The study of atrial vulnerability, initially limited to the test of provocation of the arrhythmia, has widened to include analysis of the substrate. Shortened refractory periods and regional conduction defects play a role in the creation of reentry pathways. Variations in the heart rate influence these parameters and explain the fundamental role of the autonomic nervous system on the uniformity of the activation front. The risk of atrial fibrillation is related essentially to thrombo-embolism: atrial vulnerability was investigated in 70 patients with unexplained cerebrovascular accidents. Globally, one out of two patients had pathological substrates. This study of atrial vulnerability showed that it was possible to identify a group of patients at risk of atrial fibrillation, even before the arrhythmia was recorded. This prognostic approach could also be applied to the investigation of preexcitation and syncope, and to the evaluation of the effects of pharmacological intervention.
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7786122
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[Control of ventricular response in patients with atrial fibrillation].
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The underlying treatment of atrial fibrillation comprises two possible options. In the best of cases, sinus rhythm obtained by cardioversion must be maintained by appropriate therapy. This solution is the best option for preventing the risks of embolism or of myocardial deterioration. In refractory cases, the remaining option is to control the ventricular response. The principle is to maintain the rhythm within acceptable limits (70 to 90/min at rest), an action which also aims to limit the response to effort. This results in a symptomatic improvement and protects myocardial function. Digitalis is the commonest drug used for controlling the ventricular response. It is usually successful at recommended therapeutic doses, but often fails to control the response to effort. Adjustment of dosage using plasma concentrations may improve the situation. Another method of improving the control of the ventricular response is to associate digitalis with beta-blockers or calcium inhibitors. The risk of this option is the induction of an excessive bradycardia but, on the other hand, the response to exercise can be reduced and the variations of ventricular response decreased over a 24 hour period. In forms resistant to pharmacological treatment, it is possible to intervene directly on the atrioventricular conduction pathways. Radio frequency current is used in this indication. Sometimes, the objective is only to alter atrioventricular conduction to reduce the ventricular response to atrial fibrillation. In fact, this is often difficult to obtain and a number of cases develops complete atrioventricular block. In general, the aim is to create complete atrioventricular block which is then associated with implantation of a pacemaker.(ABSTRACT TRUNCATED AT 250 WORDS)
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7786120
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[Thromboembolic complications of arrhythmia due to atrial fibrillation].
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Fifteen per cent of cerebrovascular accidents have a cardiac origin, two thirds of which are due to atrial fibrillation (AF). The Framingham study showed the risk of an ischaemic cerebral event to be increased by 5.6 in AF unrelated to rheumatic heart disease and by 17.5 when AF is associated with valvular heart disease. The risk of embolism is higher in elderly subjects and in those with underlying cardiac disease. Other high risk conditions include hypertension, diabetes, hyperthyroidism and cases with echocardiographic changes: left atrial dilatation, pre-thrombotic state or intra-atrial thrombus, atheroma of the ascending aorta. This stratification of risk should be taken into account when deciding on treatment. Conscious of the importance of the risk of embolism in AF, several authors have undertaken, over the last few years, randomised studies of the prevention of thromboembolic complications of AF: the AFASAK, BAATAF, SPAF and SPINAF trials. All showed the unquestionable efficacy of warfarin, even at low doses, at the price of a haemorrhagic risk of less than 2% per year for severe haemorrhages. A more recent study (SPAF II) confirmed the value of aspirin at the dosage of 325 mg/day which would seem to be a good alternative to anticoagulant therapy when this is contraindicated, although aspirin is less effective. The indications for anticoagulant therapy have become clearer since the publication of these results. Anticoagulant therapy is essential in permanent AF whether or not associated with rheumatic heart disease.(ABSTRACT TRUNCATED AT 250 WORDS)
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7786123
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[Mechanisms of atrial fibrillation: recent advances].
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Atrial fibrillation (AF) is due to the presence of multiple reentry pathways. Although this mechanism has been known for some time, new information has recently been acquired about the factors of atrial vulnerability and the conditions of myocardial alteration. There are two main factors of atrial vulnerability: intra-atrial conduction defects and abnormalities of the refractory periods. In addition, the concept of critical mass and the influence of the autonomic nervous system have to be taken into consideration. The abnormalities of the refractory periods liable to increase atrial vulnerability are their shortening, spatial dispersion and poor adaptation to the heart rate. All these changes may be demonstrated at cellular level. The product of the intra-atrial conduction velocity and the duration of the refractory period defines the wave length. The risk of developing reentry pathways increases as the wave length shortens. Moreover, the more the atrium fibrillates, the greater will be the decrease of the refractory periods, atrial fibrillation giving rise to atrial fibrillation. Histological lesions of the atrial tissue may be demonstrated, even in the absence of underlying cardiac disease. They mainly consist of fibrosis, fatty degeneration and myocytic hypertrophy. In the long-term, atrial fibrillation leads to a number of structural abnormalities of the atrial, and sometimes ventricular tissues, progressing to cardiomyopathy in some cases.
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7786121
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[Atrial fibrillation, restoration of sinus rhythm].
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Conversion to sinus rhythm (cardioversion) is recommended to prevent the haemodynamic and thromboembolic complications of atrial fibrillation. Prior anticoagulation is compulsory except in emergencies. The duration of anticoagulant therapy depends on the terrain and chronicity of the arrhythmia. Cardioversion may be proposed for the majority of patients in whom it is thought that sinus rhythm can be maintained by appropriate therapy. It may be carried out pharmacologically by oral or intravenous antiarrhythmic therapy. Amiodarone is the drug of choice. Cardioversion may also be carried out by external or internal direct current shock. The success rate of external electrical defibrillation depends on the energy administered, the site of the electrodes and a number of factors related to thoracic impedence. Internal electrical defibrillation may be performed with an endocavitary catheter or by the oesophageal approach, with few complications. The main problem resides in maintaining sinus rhythm in the long term. When this is not possible, cardioversion is useless, and therapy to slow the cardiac rhythm should be instituted.
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7786119
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[Epidemiology and nosology of atrial fibrillation].
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Atrial fibrillation (AF) is the most commonly encountered arrhythmia in clinical practice. It presents as chronic AF (duration > 7 days) or paroxysmal AF with intermittence of sinus rhythm giving rise to different clinical patterns which require classification. The prevalence of AF depends on the age and health of the population under consideration. The arrhythmia is exceptional in children, uncommon in young adults, but 3 to 4% of subjects over 60 years of age. Underlying cardiac disease is present in nearly 80% of cases. Valvular heart disease, though decreasing in frequency, represented 23% of cases in our hospital series. Coronary artery disease is commonly associated with AF especially in cases with left ventricular dysfunction. The relations between hypertension and AF is not clear. This relationship is more significant in the presence of left ventricular hypertrophy. Myocardial disease (hypertrophic or dilated cardiomyopathy) often underlies AF but the prognosis does not seem to be influenced by the arrhythmia. After valvular disease, cardiac failure is the most significant predictive factor of AF. Atrial fibrillation doubles the mortality and carries à 3-6% risk of systemic embolism per year, usually as a cerebrovascular accident. This risk is influenced by age, the presence of valvular disease, hypertension, previous history of myocardial infarction or cardiac failure. Idiopathic AF is a common entity (about 20% of cases in hospital series) and carries an embolic risk of 2 to 5% per year. These observations are essential for appropriate therapeutic strategy for this arrhythmia which is less benign than previously thought.
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7786118
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[Severe aneurysmal dilatation of the left atrium. Apropos of a case].
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The authors report the case of an eleven year old child with aneurysmal dilatation of the left atrial appendage and underline the diagnostic value of Doppler echocardiography in this affectation. The two signs which led to investigation of the patient and the diagnosis of this rare congenital abnormality were bulging of the left heart border on chest X-ray and atrial fibrillation. In addition to visualising a left para-cardiac chamber communicating with the left atrium on transthoracic and transoesophageal echocardiography, colour Doppler confirmed an exchange of blood between the two chambers. This aneurysm was particularly voluminous and contained echos of spontaneous contrast, a possible source of thrombosis. Thoracic CT scan and angiocardiography did not provide any further useful information. The surgical findings confirmed the presence of a large aneurysm of the left atrial appendage and excluded partial agenesis of the pericardium, the main differential diagnosis. The aneurysm was excised under cardiopulmonary bypass, and, in particular, atrial fibrillation did not recur after surgery.
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7786116
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[Does syndrome X exist?].
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The syndrome X is an entity characterised by the association of chest pain on exercise and a positive exercise stress test in patients with normal coronary angiography. However, this diagnosis can only be admitted when all other causes of angina with normal coronary arteries have been excluded. They include angina secondary to coronary artery spasm and myocardial hypertrophy. A review of the literature based on 26 publications recensing 822 patients shows that these criteria are not always respected: a really positive exercise stress test is an inclusion criterion in only 13 studies and concerns only 313 patients (38.1%); myocardial hypertrophy and coronary spasm were formally excluded in only 278 (33.3%) and 228 patients (27.7%) respectively. Taking into consideration only the patients of these 26 series with a positive exercise stress test after exclusion of coronary spasm and myocardial hypertrophy, 143 (17.4%) may be considered to be due to syndrome X. Syndrome X is a real entity but its incidence is usually overestimated. It is appropriate to distinguish it from other conditions associating, though the exercise stress test is negative, chest pain on effort and the positivity of a test considered to be indicative of myocardial ischaemia.
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7786115
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[Spondylodiscitis disclosing endocarditis on the endocavitary electrodes of cardiac pacemakers].
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Permanent pacemaker electrode infection is rare but can be fatal. The authors report two cases presenting with spondylodiscitis, a previously described mode of presentation of valve endocarditis but not previously reported in this context. In one case, recurrent courses of antibiotics did not prevent repeated episodes of bacteraemia. In the second, the relapse of infection occurred at different sites of the vertebral column until surgical removal of the electrodes: the usual features of this pathology were observed: frequent but not constant infection at the site of the pacemaker implantation, making the diagnosis more difficult; delayed signs of spondylodiscitis after implantation of the pacemaker; recurrence of infection when antibiotic therapy alone was prescribed and, therefore, the need for surgical ablation of all implanted material. The authors underline the diagnostic value of transoesophageal echocardiography.
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7786114
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[Single coronary artery].
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A single coronary artery is a rare abnormality of the coronary circulation (0.09% in the authors' experience), a fortuitous finding on coronary angiography. The authors report three new cases of this abnormality, including one with a ventricular septal defect and another with ischaemic heart disease. Exercise stress testing was positive in two patients.
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7786113
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[Infectious endocarditis induced by Actinobacillus actinomycetemcomitans. 8 new cases].
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A commensal organism of the buccal cavity, Actinobacillus actinomycetemcomitans (AAC) has been responsible for at least four new cases of infectious endocarditis by year in France. This retrospective study was based on 90 new cases of infectious endocarditis by AAC, including 8 personal observations. One third of patients had no known cardiac disease before their infectious endocarditis, the portal of entry of which was usually dental. In cases of suspected infectious endocarditis, rapid and severe weight loss (43% of cases) and, less commonly, anicteric cholestasis (8%) should alert the physician for the possible pathological role of AAC. The echocardiographic appearances are non-specific. The diagnosis is confirmed on blood cultures but the organism grows slowly in CO2 enriched atmosphere. Initially, the course of the disease was favourable in one third of patients but, in two thirds of cases, complications were observed almost renal (26%), cardiac (24%) and neurological (18%). Two thirds of patients were cured by the time they were discharged whereas the remainder had sequellae, mainly valvular and neurological. The hospital mortality was 9%; late mortality was 6%. Therefore, the prognosis of AAC endocarditis, seems to be better than that of other bacteriological forms. A combination of cephalosporin and aminoside, or even a simple third generation cephalosporin antibiotic therapy for at least 4 weeks are usually effective. The complementary surgical indications are the same as for other forms of infectious endocarditis. Prophylaxis depends on strict prophylactic amoxicillin therapy for all cardiac patients at risk of infectious endocarditis before dental treatment and on good bucco-dental hygiene.
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7786112
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[The causes of intracranial hemorrhagic complications induced by antivitamins K].
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Cerebral haemorrhage is the main life-threatening complication of oral anticoagulant therapy. In order to identify a means of prevention, the authors undertook a retrospective study of 68 consecutive cases of anticoagulant-related intracerebral haemorrhage. The mortality was 38.5%. The respective frequency of intracerebral haemorrhage, subarachnoid haemorrhage, acute and chronic subdural haematomas was 63.2, 16.2, 10.3 and 10.3%, respectively. On admission, nearly half the patients (53%) had prothrombin ratios inferior to 25%. A predisposing factor was found in 58% of cases: hypertension (30.6%), head injury (14.5%), alcoholism or drug interaction (11.2%), and one case of intracerebral aneurysm. A history of a transient ischaemic attack or of a cerebrovascular accident was found in 10.2% of cases and 11.7% had a previous anticoagulant related extracranial haemorrhage. The initial indications for oral anticoagulation were ischaemic heart disease (32%), atrial fibrillation (20.5%), secondary prevention of venous thromboembolic disease (17.6%) and primary prevention of venous thrombosis (11.7%). The duration of treatment for isolated ischaemic heart disease was over 6 months in all cases: the average duration of treatment was 12.4 months in phlebitis and pulmonary embolism. A critical review of the indications of treatment in the light of recent recommendations showed that if inappropriate indications were rare, the sometimes unnecessary prolongation of treatment was more common. Nearly half of these cases were receiving anticoagulants when the potential benefits were questionable at the time of the haemorrhagic complication. Clinical and biological follow-up is necessary for patients on anticoagulants; minor bleeding complications may be the prelude to major haemorrhage. Biological follow-up is based on control of the international normalised ratio.(ABSTRACT TRUNCATED AT 250 WORDS)
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7786111
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[Pulmonary arterial hypertension of chronic thromboembolic origin; therapeutic indications].
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Chronic thromboembolic pulmonary hypertension is a rare complication of acute pulmonary embolism. The therapeutic approach to the disease is addressed, based on a series of 81 patients referred to our department between 1984 and 1993. Medical treatment associates long-term anticoagulant therapy and, in some cases, inferior vena cava interruption. Two surgical procedures are available in selected patients: lung transplantation and pulmonary thrombo-endareterectomy. Lung transplantation has been performed in 8 patients since 1988 with 6 survivors with a maximal follow-up of 5 years. Twelve patients underwent pulmonary thromboendareterectomy with in 9 patients a dramatic functional and haemodynamic improvement. Chronic thromboembolism should be systematically investigated as the cause of pulmonary hypertension considering that in selected cases, curative surgery is possible.
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7786110
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[Right accessory pathways with slow and decremential anterograde conduction. Electrophysiological changes during ablation of the proximal atrial poles].
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Right sided accessory pathways with slow and decremential anterograde conduction differ from the anatomical substrates of the nodo-ventricular connections described by Mahaim. The connection may also be atrio-ventricular or atrio-fascicular. The authors report a series of 6 patients (2 men, average age 31 +/- 9 years) with antidromic reciprocating tachycardia implicating accessory pathways with decremential conduction (wide QRS complexes with left bundle branch block) the radiofrequency ablation of which was centered on the proximal atrial pole. The increment of pre-excitation was 75 +/- 18 ms. No nodo-ventricular or nodo-fascicular connections were observed. One patient had an atrio-ventricular connection, the mapping and ablation (5 applications) of which were performed on the annulus, as if it were a bundle of Kent. Five patients had a nodo-fascicular connection which was masked during sinus rhythm. The localisation of the proximal atrial insertion on the tricuspid annulus was initially estimated by studying the superior junction of the circuit and by endocavitary stimulation, and then by recording the M potential (activation of the accessory pathway). This was recorded in 4 patients, either at a specific point on the annulus (lateral or postero-lateral) which was the target of ablation (3 patients, 5 +/- 3 applications) or over a wider region (2 cm) at which ablation failed (1 patient: 13 applications). The site of the increment was determined in 2 patients and was proximal to the M potential. The M potential could not be recorded on the annulus in one patient. In 2 patients, the M potential was also recorded along the side of the pathway on the antero-lateral wall of the right ventricle of the tricuspid valve at its distal pole. In 2 patients, ablation was centered on the distal pole in second intention, near to the terminal part of the right bundle where it was localised in one of the two (18 applications). Finally, ablation was obtained in 5 out of 6 patients. They remain asymptomatic after 12 +/- 7 months follow-up. These cases show that accessory pathways with slow decremential conduction usually behave like a complete conduction pathway with an accessory laterally situated atrioventricular node on the tricuspid, an accessory bundle and a distal insertion which are all accessible to ablation.
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7786109
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[Isoforms of creatine kinase and myoglobin in myocardial infarct treated by thrombolysis].
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The isoforms of creatinine kinase (CK) and myoglobin were analysed by serial samplings in 45 patients admitted consecutively for myocardial infarction treated by thrombolysis according to the usual indications. Angiographic controls were carried out systematically in the first 24 hours, including 20 cases at the end of thrombolysis. The patients were divided into two groups according to the patency of the infarct related artery: Group I (n = 35) with a patent vessel and Group II (n = 10) with an occluded vessel; 4 patients in Group II were successfully revascularised by angioplasty. The total CK had a higher peak value in Group II (2,393 +/- 1,991 UI/l at 547 +/- 247 min versus 2,888 +/- 2,189 IU/l at 584 +/- 395 min) but the difference was not statistically significant. The analysis of CK isoforms showed the MM3/MM1 ratio to be higher at the 2nd hour in Group I (3.74 +/- 2.37 versus 3.09 +/- 1.43) with a faster increase, without attaining statistical significance. A fourth CK MM fraction was observed at the 2nd hour in 71% of patients in Group I compared with only 20% of patients in Group II. Analysis of myoglobin showed a significantly earlier peak value in Group I (1,218 +/- 1,117 micrograms/l at 133 +/- 62 min versus 1,309 +/- 1,549 micrograms/l at 210 +/- 84 min). The sensitivity and specificity of these different markers were respectively 40%, 86%, 77%, and 60%, 70% and 67% for the CK (peak before 8 hours), the MM3/MM1 ratio (increase of over 35% in the first hour) and myoglobin (peak before 2 hours).(ABSTRACT TRUNCATED AT 250 WORDS)
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7786108
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[Effects of repeated and prolonged inflations on immediate angiographic results and complications of coronary angioplasty. Prospective and randomized study].
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The effects of the duration of balloon inflation on the immediate and mid-term results of angioplasty were assessed in a randomized study initiated in June 1992. To date, 239 lesions in 224 consecutive patients were allocated randomly into 2 groups according to the duration of balloon inflation: short duration (123 lesions): 3 or 4 successive inflations, each < or = 1 mn, for a total duration < or = 3 min; long duration (116 lesions): 3 to 5 inflations, each of 4 to 5 minutes each for a total duration > or = 12 min. Patients with acute myocardial infarction, restenosis and lesions of bypass grafts were excluded. Stenosis (% of reduction of the internal diameter) was calculated with a digitalised Philips DCI system. Success was defined by < 50% residual stenosis in the absence of severe complications: death, emergency bypass surgery, infarction and extensive and/or occlusive dissection. The baseline clinical, haemodynamic and angiographic parameters of the two groups were comparable. The residual stenosis after angioplasty in the "short duration" group was 33 +/- 11% and 29 +/- 11% in the "long duration" group (p < 0.05). The primary success rate was 75% in the "short duration" compared to 89% in the "long duration" group (< 0.001). Angiographic dissection after angioplasty was observed in 38 cases in the "short" but only in 17 cases in the "long duration" group (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
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