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941.
Jos A. Brieva Ernesto Roldn Carmen Rodríguez Gloria Navas 《European journal of immunology》1994,24(2):362-366
Human B cells capable of spontaneous IgG secretion are commonly found in circulation and in lymphoid tissues such as tonsil and bone marrow (BM). The present study compares the mechanisms that regulate tonsil, blood and BM B cells capable of spontaneous IgG secretion. The BM cell subset produced IgG during a markedly longer period of time (14 days) than did tonsil and blood cell subsets (2–3 days). Blood and BM, but not tonsil, B cell IgG secretion depended on the presence of adherent cells, as demonstrated by adherent cell depletion and re-addition experiments. Stromal BM cells supported linear IgG secretion by non-adherent BM cells for 2 weeks, but were unable to prolong the short-term IgG secretion by tonsil and blood cells. Different factors induced IgG secretion in each of the three B cell populations as optimal IgG secretion by tonsil, blood or BM cell subsets required either tumor necrosis factor-α, interleukin-6 or fibronectin + interleukin-6, respectively. Finally, these populations also showed differences in the expression of adhesion molecules; the tonsilar cell subset was PNA+/? CD44+ CD49d+ CD49e? Leu-8+/?, the blood cell subset was PNA? CD44+/? CD49d+ CD49e? Leu-8+ and the BM cell subset was PNA? CD44+/? CD49d+ CD49e? Leu-8?. These results suggest that the mechanisms controlling the final differentiation and the expression of adhesion molecules in these B lymphocytes exhibit territorial specificity. 相似文献
942.
J. A. P. van de Nes A. A. Sluiter C. W. Pool W. Kamphorst R. Ravid D. F. Swaab 《Brain research》1994,655(1-2)
The monoclonal antibody Alz-50 is directed against Alzheimer's disease-related modified tau proteins and reveals cytoskeletal changes, i.e. neurofibrillary tangles and dystrophic neurites. The present study shows that, in the hypothalamus of non-demented control subjects, this same antibody gives a distinctive staining pattern of a subpopulation of somatostatin neurons and beaded fibers. Furthermore, Alz-50 occasionally recognizes somatostatin-containing cell bodies and dystrophic neurite-like fibers in the (neuritic) senile plaques of AD patients. These observations have direct consequences for the interpretation of Alz-50 staining in diagnostic usage and for the assessment of Alzheimer's disease-like changes induced by β-amyloid in experimental animal brains. On dot spotting, Alz-50 was found to bind to a number of fragments from the somatostatin precursor, of which somatostatin15–28 stained best. Preadsorption of Alz-50 by somatostatin15–28, as well as other specificity tests, failed, however, to provide any clue to the nature of the unknown compound(s) stained in the control hypothalamus. 相似文献
943.
Exposure of H69 small cell lung carcinoma cells to nicotinic agonists resulted in a significant increase (up to 100%) in cell number after 6 to 12 days. The effect of nicotine (10−8 M to 10−4 M) was both dose and time dependent as was that of another nicotinic agonist cytisine (10−6 M to 10−4 M). Interstingly, both the nicotine and cytisine induced increases in H69 cell number were blocked by α-bungarotoxin, as well as d-tubocurarine a nicotinic blocker which appears to interact with most nicotinic receptors. These results suggest that the nicotine induced increase in cell number is mediated through an interaction at the nicotinic α-bungarotoxin receptor. This idea is further supported by experiments which show (1) that H69 cells possess high affinity α-bungarotoxin sites (Kd = 25 nM, Bmax = 10.4 fmol/106 cells) with the characteristics of a nicotinic α-bungarotoxin receptor and (2) that the potencies of nicotinic receptor ligands in the α-bungarotoxin binding assay were similar to those observed in the functional studies. Northern analysis showed that mRNA for α7, a putative nicotinic α-bungarotoxin binding subunit, and for α5 were present in H69 cells. The present data provide further evidence that nicotine increases cell number in small cell lung carcinoma and are the first to show that this effect is mediated through an interaction at the nicotinic α-bungarotoxin receptor population. These results suggest that the α-bungarotoxin site may be involved in modulating proliferative responses in neuroendocrine derived SCLC cells. 相似文献
944.
通过对10例小儿及23例成年人的喉内肌进行的myosin-ATPase等染色观察,得到小儿和成人各喉内肌不同的肌纤维构成比。成人PCAⅠ型纤维最多,LCA、INA及CT次之,TA最少。小儿的各喉内肌也有类似比例。表明不论小儿或成人,PCA均具有较强的抗疲劳性,适应呼吸作用的需要;TA具有较快的收缩速度,以适应发声及呼吸道保护作用。从纤维构成上看,小儿与成人相比,各喉内肌Ⅰ型纤维较为匮乏,表明小儿的喉在发声及呼吸道保护等功能方面尚不够完善。 相似文献
945.
946.
We have examined 6 construction workers who developed chronic skin diseases on their hands over a period of 15 years (1970–1985). 4 developed a Trichophyton rubrum infection, and the other 2 an irritant contact dermatitis. All of them carried out jobs which caused traumatization of the skin, due to the presence of ethylene glycol and mineral oils during operation of pneumatic hammers in winter. They also suffered other types of skin trauma during their work. Construction workers may be at risk of developing an occupational skin disease involving fungal infection. 相似文献
947.
Jan Lycke Bo Svennerholm Anders Svenningsson Walter Muranyi Rolf M. Flügel Oluf Andersen 《Journal of neurology》1994,241(4):204-209
The role of human spumaretrovirus (HSRV) infections in the pathogenesis of multiple sclerosis (MS) was investigated with recombinant HSRV env-specific enzyme-linked immunosorbent assay. The presence of HSRV antibodies was determined in pairs of serum and cerebrospinal fluid (CSF) samples from 60 MS patients. In 7 of these patients serial serum and CSF samples were obtained in relation to the clinical activity of the disease during a period of 2 years. No increased antibody reactivity was demonstrable in the MS population compared with 14 aseptic meningitis patients, 50 blood donors and 16 healthy controls. Slightly elevated levels of antibodies were demonstrable in serum and/or CSF in 4 MS patients but also in 1 patient with aseptic meningitis, 1 blood donor and 1 child. No marked serum or CSF HSRV antibody fluctuation was observed in the MS patients followed longitudinally. Thus, this study does not support the involvement of HSRV in the pathogenesis of MS. 相似文献
948.
以四川地区1例无症状携带丁型肝炎病毒(HDV)和乙型肝炎病毒(HBV)患者的外周血为标本,采用逆转录-PCR技术,获得了HDV全基因组的cDNA克隆(HDVSZ93株),全长1684bp。与世界其他七个地区株相比,其核酸同源性为81.8%~95.4%;丁肝病毒抗原蛋白编码区核酸同源性为88.9%~96.1%,氨基酸同源性为86,4%~93.0%。另从1例慢性重型肝炎患者血清内克隆了丁肝病毒抗原蛋白(HDAg)编码基因(HDV-SZ92株),与SZ93株相比,亦存在若干变异。对这些不同地区、不同病情HDV株变异的可能意义进行了讨论。 相似文献
949.
Organization of dopamine D1 and D2 receptors in human striatum: receptor autoradiographic studies in Huntington's disease and schizophrenia 总被引:3,自引:0,他引:3
The technique of quantitative autoradiography was used to examine the effects of Huntington's disease (HD) and schizophrenia on the organization of striatal dopamine (DA) D1 and D2 receptors. Whereas the striatum of HD cases showed a reduction in the density of D1 ([3H]SCH 23390) and D2 ([3H]spiroperidol) receptors, the patterning of D2 receptor loss did not match that of the D1 receptor loss. The HD loss of D1 D1 receptors (65%) is far greater than the loss of D2 receptors (28%). Whereas there was a dorsal-ventral gradient of effect on both receptor subtypes, the effects of HD on D2 receptors in the ventral putamen (PUT) and nucleus accumben septi (NAS) were minimal. Similarly, muscarinic M1 and M2 receptors demonstrate different patterns of alteration in HD. The M2 subtype, labeled with [3H]N-methylscopolamine (in the presence of excess pirenzepine to occlude M1 sites), was depleted far more than the M1 receptor subtype, labeled with [3H]pirenzepine. Although the effects of HD on [3H]mazindol labeling of DA terminals were more heterogeneous, there appeared to be a relative preservation of this afferent input to the striatum of the HD cases. In the schizophrenic cases, our autoradiographic studies confirm previous reports of an elevation of D2 receptor density in the striata of many schizophrenics. This increase was evident even though two of the three cases were known to have not been treated with neuroleptics, and the third case may also have been drug naive. However, the increase was far greater in the NAS (164%) and ventral PUT (173%) than more dorsally in the striatum (68%). The density of D1 receptors and DA terminals labeled with [3H]mazindol in the striatum of schizophrenics was not significantly different from that of control cases. Thus in both HD and schizophrenia, the ratio of D2/D1 receptors is altered in favor of the D2 population, particularly in the NAS. 相似文献
950.
本文撮道了用制备电泳和柱层析二种方法结合分离纯化放射病反应性增多的A1蛋白质。方法简便,操作流程短,重复性娥经鉴定A1蛋白质是一种未见文献报道的蛋白质。以此制备抗血清可用于放射病临床治疗的监测和放射病病理机制的研究。 相似文献