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71.
Impaired proliferative responses of peripheral blood B cells from splenectomized subjects to phorbol ester and ionophore. 下载免费PDF全文
The responses of peripheral blood B cells to mitogenic stimulation were examined in 12 splenectomized subjects without residual splenic function, as determined by pitted erythrocyte counts. These were compared to a group of healthy controls matched for age and sex. Polyclonal anti-immunoglobulin evoked a normal transient elevation in intracellular free Ca2+ in splenectomized subjects, thereby suggesting that the early events of the signal transduction pathway are not impaired. However, mitogenic stimulation by pre-treatment with phorbol ester and culture in presence of a calcium ionophore (Ionomycin) resulted in reduced uptake of 3H-thymidine and subsequent proliferation. Nevertheless, entry into the mitotic cycle, as assessed by expression of Ki67, was slightly, but not significantly impaired. Unlike in normal controls, where up to 7% of freshly-isolated B cells were Ki67+, almost no Ki67+ peripheral B cells were observed in splenectomized subjects. The data are consistent with the hypothesis that peripheral B cells in splenectomized subjects are in a reduced state of activation compared with normal controls and require additional growth factor stimulation before they can undergo mitosis. 相似文献
72.
Intracellular free Ca2+ fluxes and responses to phorbol ester in T lymphocytes from healthy elderly subjects. 下载免费PDF全文
A group of healthy elderly subjects (greater than or equal to 75 years) was selected by the strict criteria of the SENIEUR protocol, and compared with healthy young (less than or equal to 35 years) volunteers. Mitogenic responses of peripheral blood mononuclear cells to phytohaemagglutinin and anti-CD3 were significantly reduced in the elderly (P less than 0.0002), thereby confirming that even though in perfect health, elderly individuals show impaired cell-mediated immunity. However, no abnormality of intracellular free Ca2+ fluxes could be detected in purified T cells from the elderly subjects when stimulated with anti-CD3 antibody. Nevertheless, both the proliferative responses of purified T cells to phorbol ester and calcium ionophore (Ionomycin) and the phorbol ester-induced inhibition of the Ca2+ response were defective in the elderly subjects (P less than 0.003 and P less than 0.0002, respectively). These data suggest that signal transduction and the generation of second messengers proceed normally in T cells from the elderly, but downstream events mediated by activation of protein kinase C are dysfunctional. 相似文献
73.
Programming life histories: Effects of maternal and environmental variables upon open-field behavior
Open-field behavior was studied as a function of three classes of variables: maternal characteristics, rearing environment, and sexual experience. Mothers of experimental subjects were either handled or nonhandled in infancy. Subjects were born and reared to weaning either in maternit cages or in Hebb-type free environments and were placed after weaning into either a laboratory cage or free enviroment. Sexual experience consisted either of bearing and raising a litter or no sexual experience. The results confirmed previous findings that offspring of mothers handled in infancy arc significantly less active in the open field than the offspring of nonhandled mothers. The maternal handling variable also interacted significantly with breeding experience: for rats which had not been bred, those raised by nonhandled mothers were more active than those raised by handled mothers; for females with breeding experience the reverse was true. Overall, thosc femalcs which had reared a litter were more active and defecated more than their nonbred littermates. 相似文献
74.
肢体缺血/再灌注后氧自由基与Bax蛋白、细胞凋亡的关系 总被引:2,自引:0,他引:2
目的 阐明氧自由基与Bax蛋白、细胞凋亡在大鼠肢体缺血 /再灌注不同时相中的变化规律及相互关系。方法 采用大鼠股动脉夹闭模型 ,阻断股动脉血流 5h后再灌注 ,设立缺血组、再灌注组 ,再灌注组设立 1,6 ,12 ,2 4h 4个检测时相 ,应用硫代巴比妥酸法测定肌肉组织中脂质过氧化产物丙二醛 (MDA)水平 ,应用免疫组化方法测定Bax蛋白表达的变化 ,应用原位末端标记法及电镜方法观察细胞凋亡现象。结果 随着再灌注时间的延长 ,MDA水平、Bax蛋白表达强度、细胞凋亡指数 (AI)进行性升高 ,且三者呈显著正相关。结论 氧自由基与细胞凋亡同时参与肢体再灌注损伤 ,氧自由基可能通过调节Bax蛋白表达促进细胞凋亡的发生。 相似文献
75.
磷脂酰胆碱500mg/kg灌胃20日可使O_3环境中的小鼠超氧化物歧化酶(SOD)活性显著增强,血浆丙二醛(MDA)含量及外周血正染红细胞(NCE)微核率明显下降。结果提示:磷脂酰胆碱具有抗氧化作用及拮抗自由基造成遗传的损伤。进一步证实了自由基在微核形成中具有重要意义。 相似文献
76.
77.
Klaus Hamprecht Matthias Vochem Andrea Baumeister Michael Boniek Christian P Speer Gerhard Jahn 《Journal of virological methods》1998,70(2):167-176
Human cytomegalovirus (HCMV) DNA can be detected in different compartments of human milk. A protocol for the preparation of milk whey free of fat and cells for the detection of human cytomegalovirus (HCMV) by nested PCR is presented. This is based upon the experience of the separation of more than 200 milk specimens of healthy seropositive breast feeding mothers. HCMV DNA could be detected in freshly centrifuged and filtrated milk whey specimens without contamination by cellular DNA. In limiting dilution experiments using HCMV plasmid DNA, the effect of different DNA extraction procedures from native milk and milk whey on the detection limit of cytomegaloviral DNA was demonstrated. About 200 viral genome equivalents/ml in milk whey or native milk were detectable by classical organic phenol/chloroform extraction or a spin column method, respectively. The detection of viral DNA in milk cells depended on a minimum number of milk cells (105–2×105) available for DNA extraction. In contrast to the findings of cytomegaloviral DNA in native sera or plasma of immunosuppressed patients we failed to amplify low level viral DNA from native breast milk by nested PCR due to an inhibition of Taq polymerase by lipid components. Finally, the course of cell associated and cell free DNAlactia was monitored. Analyzing sequential milk specimens, in some cases the presence of HCMV DNA in colostrum could be demonstrated. DNAlactia of milk cells and whey was partially discordant. Onset (week 1–4 after delivery) and duration (2 weeks up to more than 3 months) of DNAlactia showed distinct individual patterns. The methods described, allow further analysis of the mechanisms involved in the postnatal HCMV transmission by breast feeding seropositive mothers. 相似文献
78.
Increase in ferric and ferrous iron in the rat hippocampus with time after kainate-induced excitotoxic injury 总被引:4,自引:0,他引:4
Wang XS Ong WY Connor JR 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2002,143(2):137-148
The present study aimed to elucidate the distribution of ferric and ferrous iron in the hippocampus after kainate-induced neuronal injury. A modified Perl's or Turnbull's blue histochemical stain was used to demonstrate Fe3+ and Fe2+ respectively. Very light staining for iron was observed in the hippocampus, in normal or saline-injected rats and 1-day post-kainate-injected rats. At 1 week postinjection, a number of Fe3+-positive, but very few Fe2+-positive, cells were present, in the degenerating CA fields. At 1 month postinjection, large numbers of Fe3+-positive glial cells, and some Fe2+-positive blood vessels, were observed. At 2 months postinjection, large numbers of Fe3+- and Fe2+-positive glial cells were present. The labeled cells had light and electron microscopic features of oligodendrocytes, and were double labeled with CNPase, a marker for oligodendrocytes. The observation of an increasing number of Fe3+- and Fe2+-positive cells in the degenerating hippocampus with time is consistent with the results of a nuclear microscopic study, in which an increasing amount of iron was detected in the degenerating hippocampus after kainate injection. In addition, the present study showed a shift in the oxidation state of the accumulated iron, with more cells becoming Fe2+ at a late stage. A possible consequence of the high amounts of Fe2+ in the hippocampus after kainate injection is that it could promote free radical damage in the lesioned areas. 相似文献
79.
Summary A modified photometric method for the determination of phospholipase A activities which is based on a previously published reaction principle is described. The modified assay uses a lyophilized substrate emulsion rather than a freshly prepared phospholipid emulsion and a new chromogen (tribromohydroxybenzoic acid and 4-amino-antipyrine) with a high molar absorption coefficient (1,930 m2/mol at 546 nm, 2,900 m2/mol at 512 nm wavelength). The new test is more practicable with respect to pipetting volumes and incubation times. Preliminary results of a method evaluation indicate that the modified assay fulfills the usual criteria for clinical chemical enzyme measurements. 相似文献
80.
Allicin stimulates lymphocytes and elicits an antitumor effect: a possible role of p21ras 总被引:7,自引:0,他引:7
Patya M Zahalka MA Vanichkin A Rabinkov A Miron T Mirelman D Wilchek M Lander HM Novogrodsky A 《International immunology》2004,16(2):275-281
Allicin, the main organic allyl sulfur component in garlic, exhibits immune-stimulatory and antitumor properties. Allicin stimulated [(3)H]thymidine incorporation in mouse splenocytes and enhanced cell-mediated cytotoxicity in human peripheral mononuclear cells. Multiple administration (i.p.) of allicin elicited a marked antitumor effect in mice inoculated with B-16 melanoma and MCA-105 fibrosarcoma. The immune-stimulatory and antitumor effects of allicin are characterized by a bell-shaped curve, i.e. allicin at high, supra-optimal concentrations is less effective or inhibitory. Allicin induced activation of extracellular signal-regulated kinases 1 and 2 (ERK1/2) in human peripheral mononuclear cells, and also in wild-type Jurkat T-cells. Allicin failed to activate ERK1/2 in Jurkat T cells that express p21(ras), in which Cys118 was replaced by Ser. These cells are not susceptible to redox-stress modification and activation. We postulate that the immune stimulatory effect of allicin is mediated by redox-sensitive signaling such as activation of p21(ras). It is suggested that the antitumor effect of allicin is related to its immune-stimulatory properties. 相似文献