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排序方式: 共有7043条查询结果,搜索用时 31 毫秒
41.
盐酸氯胺酮-β-环糊精包合物的研究 总被引:4,自引:1,他引:3
采用正交设计法对饱和水溶液法制备盐酸氯胺酮-β-环糊精包合物的温度、时间及投料比进行选优,显微观察包合物形态,UV和X-射线衍射法测试包合物晶形变化,品尝包合物味觉效果,并测定其稳定性及溶出度。结果表明,按1:2主客克分子比,于25℃电动搅拌3h,制备包合物的包合率和收率较高,包合物已形成一种新物相,具有稳定性高,无苦味及缓释性能。 相似文献
42.
目的探讨装潢居室空气中挥发性化合物的遗传毒性.方法采用小鼠骨髓嗜多染性红细胞微核试验和小鼠精子畸形试验检测居室装潢后空气中挥发性化合物的遗传毒性.结果该化合物对小鼠呼吸系统有明显的刺激作用,与阴性对照组比较,高、中、低剂量组的微核率、精子畸形率均有显著差异性.结论居室装潢后室内空气中挥发性化合物具有遗传毒性作用. 相似文献
43.
A newly developed microscope-based imaging system was used to measure the oxygen tension (PO2) inside the retinal and choroidal vessels of mice and to generate in vivo maps of retinal PO2. These maps were generated from the phosphorescence lifetimes of an injected palladium–porphyrin compound using a frequency-domain measurement. The system was fully calibrated and used to produce retinal PO2 maps at different inspiratory oxygen fractions. PO2 rose accordingly and predictably as inspiratory O2 was stepped from hypoxic to hyperoxic conditions. Important experimental and acquisition parameters necessary for applying phosphorescence lifetime imaging to the mouse eye were investigated, including camera exposure and intensifier gain settings. Because of a need to limit light exposure to the retina, PO2 map quality as measured by the coefficient of determination was investigated as a function of signal-to-noise and accumulated excitation energy deposition. With the development of this technology for use in mice, the potential for investigating the oxygen dynamics in genetically engineered mouse models of retinal disease, including diabetic retinopathy, glaucoma, and age-related macular degeneration, is advanced. © 2003 Biomedical Engineering Society.
PAC2003: 4266Ew, 8763Lk, 8719Dd 相似文献
44.
Wiebe R. Patberg Arie Nijmeijer Jan K. Schut Adrian Versprille Jacob P. Zock Willem G. Zijlstra 《Pflügers Archiv : European journal of physiology》1992,421(2-3):280-282
In ten vagus nerves the effect of local cooling on the compound action potential was studied in the temperature range of 34 to 0 °C in spontaneously breathing, anaesthetized rabbits. The mean temperature at which the myelinated (A) fibres were completely blocked, was 10.2±2.4 °C (mean ± S.D.). In nine nerves, local vagus cooling to 0 °C failed to block all non-myelinated (C) fibres. In one nerve, total blocking occurred at 2.0 °C. We conclude that in the rabbit, the earlier found increase in tonic activity of the diaphragm following lung inflation or deflation during bilateral local vagus cooling to a temperature between 8 and 0 °C is due to afferent impulses in vagal C fibres. 相似文献
45.
前臂后皮神经营养血管远端蒂复合瓣的应用解剖 总被引:7,自引:4,他引:7
目的:为前臂后皮神经营养血管远端蒂复合瓣设计提供解剖学基础。方法:30侧动脉灌注红色乳胶成人上肢标本,解剖观测前臂后皮神经营养血管的来源、分支、吻合及其与尺、桡骨膜血管的关系。结果:前臂后皮神经营养血管来自:桡侧副动脉皮支2~6支,外径(0.6±0.3) mm;骨间后动脉皮支6~9支,外径(0.7±0.3) mm;骨间前动脉腕背支皮支3~5支,外径(0.8±0.2) mm;尺、桡动脉腕背支皮支2~6支,外径(0.6±0.1) mm。尺骨中上段骨膜血管来自骨间后动脉的肌骨膜支6~8支,外径0.3~1.0 mm;骨间后动脉桡侧骨皮支与桡骨中段裸区骨膜血管吻合。上述支发出皮支、筋膜支、骨膜支和神经营养血管,形成皮神经干血管链以及深、浅筋膜和骨膜血管网。结论:前臂后皮神经营养血管与肌、骨、皮营养血管同源,其远端蒂复合瓣,旋转轴点在腕关节平面,适宜手背远处的组织缺损修复。 相似文献
46.
人参银杏复方制剂对缺氧复氧后大鼠海马CA1区GABA、Glu表达的影响 总被引:2,自引:0,他引:2
目的:探讨人参银杏复方制剂对缺氧复氧后海马CAI区神经元的保护作用机制。方法:应用低压氧舱仿海拔8000米高空缺氧模型,采用免疫组织化学及免疫荧光方法并结合图像分析等技术,观察预防性应用人参银杏复方制剂对缺氧24h复氧0h、24h时段海马CAI区GABA、Glu表达的影响。结果:缺氧24h复氧卟组海马CAI区GABA免疫反应阳性神经元数量、Glu免疫反应阳性神经元荧光强度分别较常氧对照组减少和减弱,复氧24h后上述变化更加明显。预防性应用人参银杏复方制剂后海马CAI区GABA免疫反应阳性神经元数量在复氧0h和24h时较常氧对照组多,以复氧0h时增加最明显;Glu免疫反应阳性神经元荧光强度在复氧0h、24h时段也较缺氧复氧实验组相应时段增加。结论:人参银杏复方制剂可增加缺氧复氧后海马CAI区GABA表达及防止Glu过度释放,对缺氧复氧性脑损伤具有保护作用。 相似文献
47.
Exposure of cell cultures to organophosphorous compounds such as VX can result in cell death. However, it is not clear whether VX-induced cell death is necrotic or involves programmed cell death mechanisms. Activation of caspases, a family of cysteine proteases, is often involved in cell death, and in particular, caspase-3 activation appears to be a key event in programmed cell death processes including apoptosis. In this study, we investigated VX-induced neuronal cell death, as well as the underlying mechanism in terms of its effect on caspase-3 activity. Primary cortical neuronal cultures were prepared from gestational days 17 to 19 Sprague Dawley rat fetuses. At maturation, the cells were treated with varying concentrations of VX and cell death was evaluated by lactate dehydrogenase (LDH) release. VX induced an increase in LDH release in a concentration-dependent manner. Morphological VX-induced cell death was also characterized by using nuclear staining with propidium iodide and Hoechst 33342. VX induced a concentration- and time-dependent increase in caspase-3 activation. Caspase-3 activation was also confirmed by the proteolytic cleavage of poly(ADP-ribose)polymerase (PARP), an endogenous caspase-3 substrate. These data suggested that in rat cortical neurons, VX-induced cell death via a programmed cell death pathway that involves changes in caspase-3 protease. 相似文献
48.
复方中药注射液对小白鼠艾氏腹水癌细胞膜表面的(Na~+-K~+)-ATP酶和微绒毛影响的电镜观察 总被引:2,自引:0,他引:2
本实验应用电镜细胞化学和扫描电镜技术,观察到小白鼠艾氏腹水癌细胞在复方中药注射液的连续作用下,膜表面(Na~+-K~+)-ATP酶活性减弱,微绒毛减退等变化,同时观察到该复方中药注射液对癌细胞增殖的抑制作用,抑瘤率可达87%,癌细胞增殖和(Na~+-K~+)-ATP酶活性及微绒毛的多少有平行关系。讨论了该复方中药抑制癌细胞增殖与膜表面(Na~+-K~+)-ATP酶活性和微绒毛变化的关系。 相似文献
49.
采用熔融纺丝法制备PDLLA/HA复合纤维,探讨PDLLA/HA复合纤维的力学性能及影响因素和性能变化规律。实验结果表明:在分子量为12万的PDLLA中,加入一定量4~20μm的HA颗粒能提高复合纤维的力学性能。在PDLLA基体中添加HA的质量分数以10%为宜,以此配比制备的复合纤维的断裂强度高于其它配比复合纤维的断裂强度。采用分子量为20~30万的PDLLA制备的复合纤维断裂强度高,性能优异。复合纤维断裂强度随纤维直径的增加而下降,在直径为40~60μm时,复合纤维断裂伸长率高,弹性好。 相似文献
50.
Bloom's syndrome. XIX. Cytogenetic and population evidence for genetic heterogeneity 总被引:1,自引:0,他引:1
Cells with abnormally high rates of sister-chromatid exchange (SCE) are uniquely characteristic of Bloom's syndrome (BS). However, in one in five persons a minor population of cells with a low-SCE phenotype circulates in the blood. The origin and significance of the low-SCE cells in BS have never been understood, although they are assumed to arise by somatic mutation. In the present investigation, the enigmatic high-SCE/low-SCE mosaicism was investigated by comparing the incidence in several subpopulations of persons in the Bloom's Syndrome Registry who exhibit the two types of cells, and a striking negative correlation emerged: in persons with BS whose parents share a common ancestor, the case in approximately half of registered persons, low-SCE cells are found only rarely; conversely, the mosaicism occurs almost exclusively in persons with BS whose parents are not known to share a common ancestor. Because those who share a common ancestor are predominantly homozygous-by-descent at the mutated BS locus, the negative correlation is interpreted to mean that the emergence of low-SCE cells in BS in some way depends on the pre-existence of compound heterozygosity. A corollary to this is that BS is genetically heterogeneous. 相似文献