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11.
Impaired cortisol stress response in fish from environments polluted by PAHs,PCBs, and mercury 总被引:6,自引:0,他引:6
Alice Hontela Joseph B. Rasmussen Céline Audet Gaston Chevalier 《Archives of environmental contamination and toxicology》1992,22(3):278-283
The cortisol stress response to capture was investigated in two species of fish (Perca flavescens and Esox lucius) from sites polluted by high levels of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and mercury, and from reference sites in the St. Lawrence river system. Fish from the reference sites exhibited the normal elevation of serum cortisol in response to the acute stress of capture and had large pituitary corticotropes. In contrast, fish from the most polluted sites were unable to increase their serum cortisol in response to the acute stress of capture and their pituitary corticotropes were atrophied. These results suggest that a life-long exposure to chemical pollutants may lead to an exhaustion of the cortisol-producing endocrine system, possibly as a result of prolonged hyperactivity of the system. 相似文献
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NHS Direct usage in a GP population of children under 5 years: is NHS Direct used by people with the greatest health need? 下载免费PDF全文
This study compares health status, demographic and socioeconomic characteristics of users and non-users of NHS Direct in order to establish whether the service is being used by people with the greatest need for healthcare services. It suggests that use of NHS Direct is widespread among carers of children under 5 years old, but there is evidence that it may not be accessed equitably by those from ethnic minorities, lower socioeconomic groups and those with established ill health. 相似文献
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BACKGROUND: To investigate vergence adaptation during the incipient phase of presbyopia, when the amplitude of accommodation approaches the level where the first reading addition is required. The study aimed to assess the ability of the vergence system to counteract changes in the component contributions to the overall vergence response with the decline in the amplitude of accommodation in presbyopia, although previous reports on the nature of changes in accommodative, tonic and proximal vergence are equivocal. METHODS: Using a 'flashed' Maddox rod technique, an assessment of vergence adaptation to 6delta base-out and 6delta base-in prism was made for 28 subjects (aged 35-45 years at the commencement of the study). The measurements were taken four times over a 2-year period. RESULTS: Using a repeated measures analysis of variance, the results show that with the decline in amplitude of accommodation, there is a statistically significant reduction in the magnitude of vergence adaptation to both base-out (p < 0.05) and base-in prism (p < 0.01). CONCLUSIONS: This study shows that with ageing, there is a decrease in the ability of the slow vergence mechanism to overcome a change in fusional vergence demand and would suggest that either the fast component of fusional vergence must cope with any change in fusional vergence demand or that the sum of the accommodative, tonic and proximal vergence responses are virtually stable with age. 相似文献
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Hexane and methanol extracts of heartwood, bark/sapwood and leaves of twelve taxa of Juniperus from the United States were assayed for antifungal and antibacterial activities. The hexane extract of the heartwood of several junipers appeared comparable in antibacterial activity to streptomycin. Antibacterial activity of the hexane extracts from the bark/sapwood of J. monosperma and J. californica were comparable to streptomycin. No appreciable antibacterial activities were found in the leaf extracts from any species examined. No antifungal activities comparable to amphotericin B were found in either hexane or methanol extracts of the heartwood nor from the bark/sapwood. Antifungal activity against Cryptococcus neoformans comparable to amphotericin B was found in the hexane extract of the leaves of J. occidentalis var. australis. The methanol extracts from the leaves of J. osteosperma and J. californica had antifungal activities comparable to amphotericin B against Trichophyton mentagrophytes. 相似文献
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John E. Geltosky Richard S. Smith Alice Whalley Gary Rhodes 《Journal of clinical laboratory analysis》1987,1(2):153-162
A simple enzyme immunoassay has been developed based on measuring antibodies to synthetic peptides corresponding to sequences in the Epstein-Barr nuclear antigen (EBNA). This assay, which is reproducible, quantitative, and simple to perform and interpret, can be an effective tool to aid in the diagnosis of infectious mononucleosis and nasopharyngeal carcinoma. 相似文献