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排序方式: 共有1951条查询结果,搜索用时 15 毫秒
1.
Laboratory routines cause animal stress.   总被引:8,自引:0,他引:8  
Eighty published studies were appraised to document the potential stress associated with three routine laboratory procedures commonly performed on animals: handling, blood collection, and orogastric gavage. We defined handling as any non-invasive manipulation occurring as part of routine husbandry, including lifting an animal and cleaning or moving an animal's cage. Significant changes in physiologic parameters correlated with stress (e.g., serum or plasma concentrations of corticosterone, glucose, growth hormone or prolactin, heart rate, blood pressure, and behavior) were associated with all three procedures in multiple species in the studies we examined. The results of these studies demonstrated that animals responded with rapid, pronounced, and statistically significant elevations in stress-related responses for each of the procedures, although handling elicited variable alterations in immune system responses. Changes from baseline or control measures typically ranged from 20% to 100% or more and lasted at least 30 min or longer. We interpret these findings to indicate that laboratory routines are associated with stress, and that animals do not readily habituate to them. The data suggest that significant fear, stress, and possibly distress are predictable consequences of routine laboratory procedures, and that these phenomena have substantial scientific and humane implications for the use of animals in laboratory research.  相似文献   
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Several substances can interfere with microtubular function eg. colchicine. Melatonin, a hormone secreted by the pineal gland has similar effects as colchicine on microtubules. In this study melatonin levels were determined in both plasma and seminal plasma of patients with good or impaired motility and forward progression. There was no statistically significant difference between the mean plasma and seminal plasma values of patients with good or impaired motility and forward progression. There was no correlation between seminal plasma melatonin and impaired motility or any other semen parameter. There was also no correlation between plasma and seminal plasma concentrations of melatonin. High seminal plasma melatonin concentrations were not necessarily associated with impaired sperm motility. From these it is concluded that seminal plasma melatonin plays no important role in sperm motility.  相似文献   
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R O Barnard  J F Geddes 《Cancer》1987,60(7):1519-1531
A series of 241 gliomas (astrocytomas, oligodendrogliomas, glioblastomas, and subependymal giant-cell astrocytomas) was studied. This represents all the gliomas examined post mortem over 25 years at one hospital. Two hundred and one cases (85%) were apparently solitary tumors; of the 40 cases with multiple tumor foci, 23 (9.5%) were true multicentric gliomas. After excluding cases in which there was concomitant disease (neurofibromatosis, tuberose sclerosis, or multiple sclerosis), 18 cases of multicentric tumor (7.5%) remained. Multicentric tumors with different histologic appearances accounted for 2.9% of the series. Celloidin-embedded whole brain sections proved invaluable for the detection of microscopic neoplastic foci and unsuspected diffuse spread. The estimated incidence of multiplicity in gliomas is higher than in most series, but the findings suggest that detection of multifocal neoplastic change in these tumors is directly related to the extent to which the brain is sampled, and that figures obtained in this study may well underestimate the true incidence.  相似文献   
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A drinking water supply is a complicated system in its construction,operation,maintenance and need for public health surveillance.  相似文献   
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血管细胞粘附分子调控造血的研究进展   总被引:2,自引:1,他引:1  
本文简述了血管细胞粘附分子 (Vascularcelladhesionmolecule 1,VCAM 1)的结构和生物学功能 ,总结了VCAM 1在恶性血液病骨髓基质中的表达和意义 ,探讨了VCAM 1在造血干细胞动员和归巢中的作用 ,指出VCAM 1作用机制的深入研究将对恶性血液病的治疗提供更为有效的方法。  相似文献   
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This communication describes the design and application of a receiver coil operating at liquid nitrogen temperature and intended as a surface coil in a whole-body imager. Its particular application is seen as the external receiver for parasitic internal or implanted detectors.  相似文献   
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Transforming growth factor beta is a polypeptide growth factor with a multiplicity of diverse biologic effects. Increasingly, data support a role for TGF beta in the autocrine regulation of normal epithelial cell growth (Figure 1). Definition of the normal pathways for growth stimulation and inhibition of epithelial cell growth by autocrine peptides like TGF beta and TGF alpha undoubtedly will increase understanding of normal growth and development, embryogenesis, wound repair, and tumorigenesis.  相似文献   
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