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Most insecticides are neurotoxicants causing various forms of hyperexcitation and paralysis in animals. A variety of neuroreceptors and ion channels have been identified as the major target sites of these neurotoxic insecticides. This paper gives the highlights of some of the recent development in this area. Pyrethroids keep the sodium channel open for unusually long times causing a prolonged flow of sodium current. The prolonged sodium current elevates and prolongs the depolarizing after-potential which reaches the threshold membrane potential to initiate repetitive after-discharges. We have developed the method with which the percentage of sodium channel population that needs to be modified to cause repetitive after-discharges can be measured accurately. In rat cerebellar Purkinje neurons, only 0.6% of sodium channels needs to be modified for hyperexcitation resulting in a large toxicity amplification. This concept is applicable to other neuroactive drugs that act through the threshold phenomenon. The mechanisms of selective toxicity of pyrethroids in mammals and insects have been quantitatively determined to be due mainly to the different sensitivity of the sodium channels to pyrethroids and the negative temperature dependence of pyrethroid action on the sodium channels. The degradation of pyrethroids play only a minor role. The negative temperature dependence of pyrethroid action is due to the increased sodium current flow at low temperature. The major site of action of dieldrin and hexachlorocyclohexane is the GABA(A) receptor chloride channel complex. Dieldrin exerts a dual action, initial stimulation and subsequent suppression, and the latter is responsible for hyperexcitation of animals. Dieldrin stimulation requires the gamma2s subunit in the GABA receptor, whereas dieldrin suppression occurs in the presence or absence of the gamma2s subunit.  相似文献   

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A retrospective review of the medical records of blunt trauma patients with sternal fracture admitted to a level 1 trauma center from June 1990 to June 1993 was undertaken to determine the relationship between sternal fractures and clinically significant myocardial injury, and to assess the usefulness of cardiac evaluation and monitoring in these patients. Of 33 patients with sternal fracture, 31 were in motor vehicle crashes and 2 were pedestrians struck. All had Glasgow Coma Scale score = 15. No patient had a severe, life-threatening, associated injury (Abbreviated Injury Score of >3). No electrocardiogram or echocardiogram showed evidence of acute injury or ischemia. No arrhythmias requiring treatment were noted. No CPK-MB fraction was >5%. These results show that sternal fracture is not a marker for clinically significant myocardial injury. The management of sternal fracture patients should be directed toward the treatment of associated injuries.  相似文献   

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The relation among physicians is quite frequently characterized by conflicts. The different types of problems which may come up are discussed, and finally the author tries to formulate some rules which could improve the situation.  相似文献   

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STUDY OBJECTIVE: To compare the levels of work-related stress and depression reported by practicing emergency physicians in three survey sites and to determine the effects of gender and marital status on the stress and depression experienced by these physicians. DESIGN: Cross-sectional mail surveys. SETTING AND PARTICIPANTS: Seven hundred sixty-four practicing emergency physicians from the United States, 91 fellows in full-time practice from Australasia, and 154 consultants and 47 senior registrars from the United Kingdom. INTERVENTION: Administration of questionnaires requesting demographic information and including an inventory to assess work-related stress and a scale to measure depressive symptomatology. MEASUREMENTS AND MAIN RESULTS: A 3 x 2 x 2 multivariate analysis of variance performed to compare scores on the stress inventory and depression scale simultaneously by survey site, gender, and marital status revealed significant differences in stress and depression by survey site and marital status. Univariate analyses of variance revealed significant differences in both stress and depression among the three survey sites and in depression by marital status. Adjusted means indicated that physicians from the United Kingdom reported higher levels of stress and depression than physicians from the United States and Australasia. Physicians from the United States and Australasia did not differ with respect to stress or depression. Physicians who were not married reported higher levels of depression than married physicians. No large mean differences, actual or adjusted, were found for any of the grouping factors. CONCLUSION: Statistical differences among practicing emergency physicians from the United States, Australasia, and the United Kingdom were observed, but the actual levels of work-related stress and depression were similar and did not appear severe. Marriage was associated with lower levels of depressive symptomatology.  相似文献   

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Self-care, although growing as a concept and a movement among providers and consumers, has not been studied systematically in any dimension. Because of the potential role of physicians in establishing the credibility and acceptability of self-care interventions and practices, an exploratory investigation was launched to develop an attitude instrument, to describe the degree to which practicing physicians in a community favor self-care, and to explore some of the correlates of the attitudes expressed. A 13-item attitude scale was developed. Physicians with the most favorable attitudes were most likely to have come from a Jewish religious background, to be under 46 years old, to have health beliefs which reflect an internal locus of control, and to be in a group practice or clinic. Physicians with the least favorable attitudes came from Protestant backgrounds, were 46 to 63 years old, had externally controlled health beliefs, and practiced medicine alone.  相似文献   

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Utilizing a prospective longitudinal design, the recovery pattern of 91 heart patients was followed for the first 8 weeks following coronary artery by-pass graft surgery. The patients' perceived and actual performance of walking, their resumption of roles, and social support and family functioning were measured pre-operatively and at 4 and 8 weeks postoperatively. Findings indicate that recovery is swift in terms of health and physical functioning, somewhat more time-consuming in terms of role functioning, and delayed with regard to work-related role activities. Contrary to American findings, the heart surgery recovery process did not significantly affect family functioning in this Norwegian sample. Social support was experienced as high throughout the recovery period, with spouses and children being the main providers.  相似文献   

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We evaluated eight children with thoracic or high lumbar-level paraparesis for metabolic performance while ambulating with custom fabricated thermoplastic hip-knee-ankle-foot orthoses (HKAFOs) and reciprocating-gait orthoses (RGOs). Seven of the eight children had myelomeningocele. Each patient was tested in both systems at self-selected speeds in a crossover study design. At self-selected speeds, the level of exercise intensity for both thoracic and high-lumbar patients with either orthosis was lower than that for normal children. The average metabolic cost of walking in the RGO was twice that of normal children, as compared with six times normal in HKAFOs. For the four thoracic-level patients, there was a significantly higher oxygen cost of ambulation in using HKAFOs versus RGOs. No significant difference in metabolic performance was found for the high-lumbar patients. Velocity of ambulation was faster in the RGOs than in the HKAFOs. For thoracic-level patients, our data suggest that an RGO will provide a faster, more energy-efficient gait than a statically locked HKAFO. For high-lumbar patients, no significant difference was found between the two orthoses. Seven of eight children preferred the RGO over the HKAFO.  相似文献   

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As part of a nation-wide questionnaire survey among Danish doctors, the incidence of hepatitis B vaccination was studied. For each specialty the findings were related to the risk of hepatitis B exposure assessed by the incidence of percutaneous and mucocutaneous blood exposure (PCE and MCE). A total of 6256 of 9375 doctors (67%) responded and 6005 (64%) questionnaires were eligible for analysis. Only 34.3% of the doctors had been vaccinated against hepatitis B, ranging from 8.9% in Psychiatry to 56.9% in Obstetrics-Gynaecology. The annual incidence of PCE and MCE was high in surgical as well as non-surgical specialties with an average of 3.0 PCE and 3.9 MCE per person. In conclusion all doctors must be considered at risk of exposure to hepatitis B during part of or the entire career. The current level of hepatitis B vaccination is insufficient. Hepatitis B vaccination of all doctors before entering clinical work seems to be indicated.  相似文献   

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Differences in cord serum low density lipoprotein (LDL) composition between male and female neonates with normal or high (> or = 100 mg/dl or > or = 2.59 mmol/l) serum cholesterol levels were studied in 548 full-term newborn infants of the Toledo Study (Spain), where the absence of known perinatal factors that would alter lipid levels in cord blood was confirmed. The percentage of females with a high serum total cholesterol (TC) level was higher (p < 0.02) than that of males. ANOVA two-way analysis shows significant interaction of gender and cholesterol level upon LDL-cholesterol, triglycerides and LDL-cholesterol/Apoprotein (Apo) B ratio. However, Apo B was higher in those neonates, both male and female, with high cholesterol levels. The LDL fraction carried about 55% of TC in females with high TC levels (HF), whereas it transported just 40% in males with high TC levels (HM). LDL appeared more enriched in cholesterol than in Apo B in HF than in HM (p < 0.01). An increased level of small LDL particles should be associated with the higher triglyceride level found amongst HM. Results in LDL composition suggest that metabolic gender-related differences in infants with normal or high TC are presented at birth.  相似文献   

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Adenovirus infection of the gastrointestinal tract in human immunodeficiency virus (HIV)-infected patients is rarely reported, probably because of a lack of familiarity of most pathologists with diagnostic criteria during routine light microscopy and possible misidentification as cytomegalovirus infection. We studied colonoscopic biopsy specimens from 135 HIV-infected patients with clinically suspected cytomegalovirus colitis during a 4.5-year period to morphologically identify the presence of adenovirus infection. Immunohistochemical staining for adenovirus was performed for confirmation on all suspected cases. Adenovirus infected cells showed characteristic amphophilic or eosinophilic nuclear inclusions, predominantly affecting the surface epithelium and characteristically involving goblet cells. Sixteen cases showed morphologic features of adenovirus infection, all confirmed by immunohistochemistry. Twelve cases also showed cytomegalovirus infection, whereas 4 showed adenovirus alone. In 10 cases, adenovirus colitis was not recognized during initial routine histopathologic diagnostic evaluation. Adenovirus inclusions also were discovered in the stomach, the duodenum, and the liver in single cases. Conclusions are as follows: (1) Adenovirus colitis has been underdiagnosed at our institution and, we suspect, in general. (2) The morphologic features and nuclear inclusions of adenovirus colitis are characteristic and can be identified reliably by routine light microscopy. (3) Adenovirus infection also may be diagnosed morphologically in extracolonic sites, such as the stomach, the small intestine, and the liver. (4) Coinfection of adenovirus with cytomegalovirus and other agents is seen frequently, but, less frequently, adenovirus may be identified as a sole pathogen.  相似文献   

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Drug addiction among physicians appears to be an occupational hazard, with chronic pain, depression, and the easy availability of drugs major factors leading to addiction. In this study of 46 cases of physician addicts handled by the Virginia State Board of Medicine, meperidine hydrochloride (Demerol) was the most frequent addictive agent. The Virginia disciplinary and therapeutic plan for addicted physicians was effective in successfully rehabilitating and returning to medical practice 72% of the 46 physician addicts reported to the board from 1949 to 1974.  相似文献   

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We conducted a retrospective longitudinal self-controlled study of 64 patients aged 4-19 years treated with resective surgery for partial epilepsy from 1952 to 1988. Approximately 60% of patients experienced > 95% reduction in seizure frequency, and 70% had worthwhile improvement of at least 75% reduction. Seizure relief was more frequent among patients who underwent operation after 1978, and significant differences by time period of operation were noted for those with temporal lobe excisions and patients with normal tissue histology. The region of resection and the age at treatment did not provide significant information with respect to seizure outcome. Postresection electrocorticography (ECoG) and EEG of the first postoperative year predicted later seizure outcome. Small neurologic deficits were more common among patients resected in the temporal lobe than in patients resected in the frontal lobe. Half of the patients with preoperative unilateral focal activity and a third of those with bilateral focal activity had normal EEG postoperatively. One fourth had discontinued antiepileptic drug (AED) therapy. As expected, long-term mortality was significantly higher than the mortality of the general population. Seven patients died during follow-up. Two male patients committed suicide.  相似文献   

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European study of General Practice (GP) task profiles was carried out in 30 European countries in 1993. We analyzed the Norwegian results. 164 primary care physicians, 51% of a random sample, answered a questionnaire. 147 kept a diary on their practice for one week. Compared with results from two earlier studies performed 15 years ago, the proportion of female GPs had doubled to 25%, there were more group practices, more time was spent on vocational training and continuous education, and night service was less frequent than in 1978. 45% were specialists in general practice and 7% in community medicine. Job satisfaction was high, and highest for women, fee-for-service GPs on contract, and GPs who cooperated with other health professionals.  相似文献   

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For several years the high turnover of doctors in municipal public health positions has been a cause of concern in Norway. More information on the causes of the higher turnover, and of factors that could promote greater satisfaction, could provide a basis for discussing what needs to be done. In order to find out the main sources of satisfaction, or dissatisfaction, and their relative importance, a questionnaire was mailed to all doctors in public health positions from 1988 through 1991. They were asked about 12 different aspects of their jobs and general family well-being. 218 (81%) of the doctors who had held such a position for the whole period ("the stable"), and 98 (87%) of those who had quit ("the quitters") responded. Sources of great satisfaction were opportunities for outdoor recreation and the well-being of the family. The doctors were least satisfied with the level of income and the heavy load of work. When asked to state the most important sources of satisfaction, both stable and quitters gave first priority to the professional content of the work and collaboration with colleagues. The stable also gave high priority to general family well-being. For the quitters, an important negative factor was the heavy work load. About 27% of the stable and 42% of the quitters thought the job required too much effort. More of the stable group than of the quitters felt professionally competent, and that they were doing a good job. On the other hand, more of the quitters than of the stable group felt they had little influence on the local health policy, and that the job was uninteresting. In the efforts to reduce the turnover of doctors in public health positions, the health authorities should consider the wider aspects of the job, not just the wage. To increase stability and job satisfaction, greater attention should be given to the professional content of the work, the need for professional collaboration, and the heavy work load.  相似文献   

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CONCLUSION: The diagnosis of a pancreatic carcinoid should be based on the measurement of serotonin in serum or its demonstration in the tumor and/or by the measurement of its derivative (5-HIAA) in urine. Carcinoid of the pancreas is a rare but definite entity; usually having metastasized by the time of diagnosis. The term "serotonin-producing tumor of the pancreas" has been suggested as an alternative designation for "pancreatic carcinoid." BACKGROUND: The literature on carcinoid tumors of the pancreas is confusing because much of it preceded the development of the more specific immunological, chemical and staining techniques currently available. METHODS: 43 case reports were collected from the world's literature, based on a demonstrable pancreatic neuroendocrine tumor plus a positive finding of at least one of the following without another dominant hormone being demonstrated: elevation of 5-Hydroxytryptamine (5-HT) (serotonin) in the serum or detected in tumor tissue, and/or elevation of 5-Hydroxyindole acetic acid (5-HIAA) in the urine. In addition to these two hormone-specific assays, information was collected on the silver-staining properties of the tumor; properties which have traditionally been associated with carcinoid tumors. Positive silver staining in tumor cells (argyrophilic and/or argentaffin reaction) is strongly indicative of the carcinoid tumor but the findings are less specific than the hormone assays and immunohistologic stains. RESULTS: In this review of 43 cases, including two current ones, the pancreatic carcinoid tumor has the following important features: 1. It is a rare tumor that is usually diagnosed late when the tumor is large and has metastasized. Thirty-eight (88.4%) have been malignant. They are, therefore, associated with a high incidence of the "carcinoid syndrome." 2. To date, prognosis in therapy is poor, based on delayed diagnosis, a resultant low incidence of resectability, and an uncertain duration of survival after resection. 3. Pancreatic carcinoid tumors remain difficult to differentiate from other endocrine tumors. The measurement of urinary 5-HIAA excretion or the demonstration of elevated serotonin level in the tumor or in serum is essential to its distinction. Silver staining of the tumor, although of historic importance, has been superceded by the hormone-specific studies. 4. To distinguish it from other endocrine tumors of the pancreas, the terms "pancreatic serotoninoma" or "serotonin-producing tumor of the pancreas" have been suggested as possible alternatives. Its growth characteristics may be related more to its cell of origin than to its extent of hormone secretion. Not all of the tumors result in recognizable hyperserotoninemia.  相似文献   

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This investigation examined potential antecedents and consequences of burnout in a large sample of Norwegian police officers. Data were collected via anonymously completed questionnaires. Three burnout components considered were emotional exhaustion, cynicism, and low professional efficacy. Work demands emerged in hierarchical regression analyses as the strongest predictor of each burnout component. With the burnout components as predictors, hierarchical regression analyses indicated that burnout components had significant relationships with a variety of outcomes (work, work-family, psychological health, physical health). Work demands, however, had a stronger relationship with both work and work-family outcomes than did the burnout components, the latter having the strongest relationship with indicators of psychological health. Emotional exhaustion had significant and independent relationships with most of the outcome measures. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

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