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71.
72.
Histomorphometric study was made on a series of sections of undecalcified epiphyseal femoral specimens from rats with experimental fluorosis. The results revealed osteosclerosis in Group A (5 ppm) being more severe than that in Group B (25 ppm) With the increase of fluoride dose, the parameters fell down instead of increased in parallel. There is seemingly a threshold over which osteosclerosis in fluorosis becomes less severe. In contrast to Bely's conclusion the authors proposed that, fluoride toxi- city, besides decreasing the number of osteoblasts, may also activate the osteoblasts. The number of osteoblasts may be increased with relative lower dose of fluoride also. The net outcome is the in crement in bone volume. When toxic dose of fluoride is higher enough (higher than the proposed threshold), however, the number of osteoblasts and its activity are inhibited. So are the osteocytes. This interpretation may be the cytological basis for osteosclerosis in the experimental fluorosis.  相似文献   
73.
目的 :为了探讨CD2 8协同刺激分子在结核杆菌 (Mtb)低分子多肽抗原体外激活人外周血γδ T细胞中的作用。方法 :采用激发型抗CD2 8单抗模拟第二信号 ,Mtb低分子多肽抗原作为刺激原 ,对纯化的人外周血T细胞进行体外刺激和培养 ;用流式细胞仪检测γδ T细胞上CD2 8分子的表达、γδ T细胞的增殖效应及活化的γδ T细胞上CD6 9分子的表达。结果 :人外周血γδ T细胞中有 5 0 %左右表达CD2 8分子 ;抗CD2 8单抗协同Mtb抗原可刺激γδ T细胞的活化和增殖 ;但抗CD2 8单抗或Mtb抗原单独刺激则无作用。活化的γδ T细胞表面表达CD6 9分子。结论 :Mtb抗原在选择性活化人外周血γδ T细胞时需要第二信号的参与 ;CD2 8在Mtb抗原激活γδ T细胞时可提供协同刺激信号 ;CD6 9可作为γδ T细胞的早期活化标志。  相似文献   
74.
M W Long  N Williams 《Blood》1981,58(5):1032-1039
Three types of immature megakaryocytes, detected by their morphological properties, have been characterized in bone marrow of normal C57BL/6 mice. Morphological classification of these cells was carried out by determining (1) presence and relative amount of acetylcholinesterase, (2) cell size, (3) nuclear/cytoplasm ratio, and (4) nuclear shape. The immature megakaryocytes were classified as: (A) cells distinguished by a round nucleus (10.6 +/- 1.1 mu diameter; mean +/- SEM), which had the highest nucleus / cytoplasm ratio and lowest content of acetylcholinesterase; (B) cells with an indented nucleus (13.0 +/- 1.9 mu diameter), which had increased acetylcholinesterase content and reduced nucleus/cytoplasm ratio compared to the round-nucleus cell type; and (C) lobed-nucleus cells (14.5 +/- 2.9 mu diameter), which showed further increase in acetylcholinesterase content and reduction in nucleus/cytoplasm ratio. Increased numbers of immature megakaryocytes were detected, indicating that a proportion of these cells are undetected using conventional staining techniques. Based on the observed alterations in size, acetylcholinesterase content, and nuclear complexity, it was concluded that these cells constitute part of a progressive maturation sequence intermediate between the progenitor cell (CFU-Mk) and mature easily recognizable megakaryocytes.  相似文献   
75.
神经活素对Pc12细胞作用的初步观察   总被引:1,自引:0,他引:1  
从胎脑、颌下腺、肌肉组织中制备神经活素。其性能同脑活素一样:可促进Pc12细胞的突起生长,提高其胞浆内乳酸脱氢酶活性,电泳显示二者有相同的三条带。提示:神经活素有可能替代脑活素应用于临床。  相似文献   
76.
Two elderly patients, involved in separate motor vehicle accidents, sustained blunt chest injury resulting in rupture of their thoracic aortas. The initial chest radiographs showed the presence of a calcified ring fractured in two places with lateral displacement of a calcified fragment by haematoma. This ‘broken halo sign’ is a radiographic sign not previously well described in the literature. The presence of a disrupted aortic ring in the elderly patient, associated with the appropriate mechanism of injury, should alert the clinician to the potential diagnosis of traumatic rupture of the thoracic aorta (TRTA).  相似文献   
77.
78.
人皮质骨矿化基质中骨盐框架结构   总被引:2,自引:0,他引:2  
目的:研究人皮质骨矿化基质中骨盐的框架结构及框架中骨微间隙。方法:应用透射电镜、场发射扫描电镜观察、电脑图像分析及能谱分析,分析无骨病成人长骨、扁骨200例骨盐分布特征。结果:骨盐框架结构由微柱、微梁、微小梁、弓状梁、致密点、隔板和骨微间隙构成。骨微间隙由洞、内衬和壁组成,洞平均直径为84.4±75.6nm,与骨小管相比有显著差异(P值<0.001),平均密度为11~17个/μm2,与骨小管之比超过10:1。骨盐分针形结晶和微颗粒结晶。结论:骨盐框架结构及骨微间隙是骨盐在人皮质骨矿化基质中的存在形式,可能与骨盐吸收、沉着有关。  相似文献   
79.
Nitric oxide (NO), originally identified as the mediator of endothelial-dependent relaxation of vascular smooth muscle, is now known to also have cytotoxic effects under certain conditions. Thus, we have investigated the effects of inhibition of NO synthesis on ischemia/reperfusion injury in the rabbit rectus femoris muscle. Three and a half hours of ischemia and 24 hours of reperfusion resulted in a 56% loss of viability. In muscles receiving an infusion of the nitric oxide synthase inhibitor, L-NIO (30 μM), the loss of viability was reduced to 15%. Post-ischemic blood flow was increased in muscles receiving a saline infusion, whereas there was a marked decrease in blood flow for at least the first 60 minutes of reperfusion in muscles treated with L-NIO (30 μM). The increase in myeloperoxidase levels (indicative of neutrophil accumulation) following 24 hours of reperfusion was attenuated with L-NIO infusion by approximately 50% and the reperfusion-induced edema was also attenuated in L-NIO treated muscle. These findings suggest that endogenous NO production during ischemia/reperfusion injury may be deleterious to muscle survival. © 1994 Wiley-Liss, Inc.  相似文献   
80.
用PCR—RFLP和16SrDNA指纹图法分析幽门螺杆菌基因型   总被引:1,自引:1,他引:0  
本文建立了PCR-RFLP和16srDNA指纹图法.对19株幽门螺杆菌(HP)进行基因型分析:HP尿素酶C基因的PCR扩增产物.分别用HindⅢ、HaeⅢ、AluⅠ酶切,结果显示:每个酶均将19株HP分为3种RFLP图谱.综合HindⅢ,HaeⅢ和AluⅠ酶切结果,19株HP分为10个酶切带型;PCR扩增HP标准株16SrRNA基因,地高辛标记制备550bp探针,19株HPDNA分别经HaeⅢ和EcoRⅠ酶切、电泳后,通过Southern杂交获16SrDNA指纹图,结果显示:HaeⅢ酶切分为14个杂交带型,EcoRⅠ酶切19株HP杂交带型均不同。本实验表明:上述两种方法重复性好,分群力高,可准确有效地对HP作出鉴定并将其分型。19株HP株间存在基因型差异。  相似文献   
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