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排序方式: 共有518条查询结果,搜索用时 20 毫秒
1.
The effect of acute infection of mice with lactic dehydrogenase virus (LDV) on two major functions of peritoneal macrophages was tested. Using a macrophage-dependent T cell proliferative assay to test the antigen-presenting capacity of LDV-infected macrophages we found that LDV impairs the capacity of antigen-presenting cells to trigger memory T lymphocytes. Endocytosis of antigen by LDV-infected macrophages was similar to that of uninfected cells. In addition, the proportion of intracellular antigen versus membrane-bound antigen in LDV-infected cells were similar to that observed in uninfected mice. It appears therefore, that the impaired immunogenic effect of LDV-infected macrophages results from reduced immunogenicity of the membrane-bound antigen.Testing the phagocytic activity of peritoneal macrophages we found that the uptake of radiolabeled antibody-coated sheep erythrocytes or bacteria (E. coli) by infected cells was similar to that by uninfected macrophages. In addition, LDV failed to affect the ability of peritoneal macrophages in a nitroblue tetrazolium reduction reaction which serves as an alternative parameter for measuring phagocytic activity. Our results support the assumption that LDV, which probably propagates in the cells of the reticuloendothelial system, impairs some of the immunogenic functions of macrophages and thereby affects macrophage-dependent immune responses. 相似文献
2.
Satoshi Mochida Itsuro Ogata Yasuhiko Ohta Teruaki Oka Kenji Fujiwara 《Pathology international》1991,41(3):217-220
In order to investigate superoxide production by pulmonary macrophages in the rat, a route was created by ligating both the inferior and superior venae cavae and resecting the aorta after cannulation through the inferior vena cava into the right atrium of the heart. Lung perfusion was performed via this route with nitro blue tetrazolium. Although there was no formazan deposition throughout the lung, it became detectable in both alveolar and interstitial macrophages when phorbol myristate acetate was added to the perfusate. This deposition was markedly enhanced by previous injection of Corynebacterium parvum. The deposition disappeared after further addition of Cu(Lys)2 , a scavenger of superoxide anions. This procedure may be useful for estimating in situ the ability of pulmonary macrophages to produce superoxide in the rat. 相似文献
3.
Cross-sectional areas and lactate dehydrogenase activity were determined of separate muscle fibres of mouse rectus femoris muscle in both ventral and dorsal parts of the muscle. The lactate dehydrogenase activity was measured quantitatively by microscope photometry using a tetrazolium staining in absence or presence of either vitamin K3 or phenazine methosulfate. If the observations are restricted to a relatively small area of the muscle cross section, one can distinguish categorically narrow ("red") and broad ("white) fibres with average values for cross sectional area and LDH content that depend on the part of the muscle chosen (higher LDH and smaller area in ventral part). However, if these data from the different parts or from the whole muscle are added together, no categorical distinction between the fibre types is allowed. On the basis of the observations a categorical division of muscle fibres within relatively large muscle areas or in a whole muscle is rather dubious. A relation is suggested between the subjective impression of different muscle fibre types in a field of observation with the number of motorunits present in that field. 相似文献
4.
Rapid colorimetric assay for cell viability: application to the quantitation of cytotoxic and growth inhibitory lymphokines 总被引:34,自引:0,他引:34
A rapid colormetric microtiter assay has been developed to detect cytotoxic lymphokines produced by human lymphocytes activated with lectins or tumor cells. The viability of lymphotoxin-treated target cells was detected using a tetrazolium dye that is reduced to a blue formazan by living but not dead cells. The amount of dye formed was quantitated using a microplate spectrophotometer (ELISA plate reader) and visual observations confirmed the amount of formazan dye produced was directly proportional to the number of viable target cells. The advantages of using this colormetric method are that it requires no washing steps or radioisotopes and its precision and rapidity. Optimal conditions were established using the murine L929 and human ESH-5L cell lines as target cells for detecting lymphotoxins produced by human lymphocytes. The data indicate that the L929 cell line was 10–50-fold more sensitive than the ESH-5L line to the lytic activity of cytotoxins produced by human phytohemagglutinin-P-activated T lymphocytes, or the cytotoxins produced by peripheral blood lymphocytes stimulated with various tumor cell lines. This assay system was also useful in detecting antibodies capable of neutralizing lymphotoxin activity and thus should be a suitable method to aid in the molecular characterization of these lymphokines. 相似文献
5.
A rapid colormetric microtiter assay has been developed to detect cytotoxic lymphokines produced by human lymphocytes activated with lectins or tumor cells. The viability of lymphotoxin-treated target cells was detected using a tetrazolium dye that is reduced to a blue formazan by living but not dead cells. The amount of dye formed was quantitated using a microplate spectrophotometer (ELISA plate reader) and visual observations confirmed the amount of formazan dye produced was directly proportional to the number of viable target cells. The advantages of using this colormetric method are that it requires no washing steps or radioisotopes and its precision and rapidity. Optimal conditions were established using the murine L929 and human ESH-5L cell lines as target cells for detecting lymphotoxins produced by human lymphocytes. The data indicate that the L929 cell line was 10–50-fold more sensitive than the ESH-5L line to the lytic activity of cytotoxins produced by human phytohemagglutinin-P-activated T lymphocytes, or the cytotoxins produced by peripheral blood lymphocytes stimulated with various tumor cell lines. This assay system was also useful in detecting antibodies capable of neutralizing lymphotoxin activity and thus should be a suitable method to aid in the molecular characterization of these lymphokines. 相似文献
6.
Reported parameters of the MTT assay vary widely, and reflect a need to optimise the assay for different cell types. The MTT assay conditions for the human B-lymphocyte-derived cell line WIL2NS were optimised for MTT incubation and formazan development. The optimised MTT assay was validated by examining the effects of the acaride amitraz on WIL2NS. In pH-buffered media in the absence of cells, MTT formed formazan spontaneously, and absorbance was proportional to both the initial concentration of MTT and the time of incubation at 37 °C. One milligram per millilitre MTT was toxic to WIL2NS cells, but the accuracy of the standard curve was reduced when only 0.2 mg/ml MTT was used. Twenty percent SDS in 0.2 M HCl was preferable to DMSO as a solvent for formazan. Exposure to 0.035% amitraz resulted in a significant reduction in WIL2NS cell numbers after only 2 h of exposure. It was concluded that 0.035% of amitraz has the potential to adversely affect lymphocytes in the systemic blood system in humans, and that an optimised MTT assay was obtained by incubating WIL2NS cells with 0.45 mg/ml MTT for 17 h, followed by addition of acidified SDS for 1 h. 相似文献
7.
8.
Quinocetone (QCT) is a new feeding antibacterial agent in the QdNOs family. The mechanism of its adrenal toxicity is far from clear. This study was conducted to estimate the adrenal cell damage induced by QCT and its bidesoxy-quinocetone (B-QCT) metabolite and to further investigate their mechanisms. Following doses of QCT increasing from 5 to 50 μM, cell apoptosis and necrosis, mitochondrial dysfunction and redox imbalance were observed in porcine adrenocortical cells. The mRNA levels of the six components of intermediary enzymes and the adrenal renin-angiotensin-aldosterone system (RAAS) displayed a dysregulation induced by QCT, indicating that QCT might influence aldosterone secretion not only through the upstream of the production but also through the downstream of the adrenal RAAS pathway. In contrast, B-QCT had few toxic effects on the cell apoptosis, mitochondrial dysfunction and redox imbalance. Moreover, LCMS-IT-TOF analysis showed that no desoxy metabolites of QCT were found in either cell lysate or supernatant samples. In conclusion, we reported on the cytotoxicity in porcine adrenocortical cells exposed to QCT via oxidative stress, which raised awareness that its toxic effects resulted from N→O groups, and its toxic mechanism might involve the interference of the steroid hormone biosynthesis pathway. 相似文献
9.
目的 研究大鼠局灶性脑缺血再灌注MRI弥散加权成像(DWI)的变化,探讨其与TIC染色变化的关系. 方法 44只雄性SD大鼠按随机数字表法分为假手术组和脑缺血2h、脑缺血6h再灌注不同时间组(0 h、0.5h、2h、6h、24 h),每组各4只.脑缺血2h组、脑缺血6h组采用线栓法制作成大脑中动脉栓塞模型.各组大鼠于不同再灌注时间点行MRI DWI扫描,结束后立即处死,取相应部位脑组织行TTC染色,观察分析其与DWI成像的关系. 结果 脑缺血2h组、脑缺血6h组再灌注0h均可见部分右侧大脑半球DWI呈高信号,表观扩散系数(ADC)值降低,TTC染色可见部分右侧大脑半球失染呈白色.缺血2h组再灌注24 h后DWI异常信号区相对面积明显变小,ADC值增大,TTC失染相对面积变小,较再灌注0h差异有统计学意义(P<0.05),而脑缺血6h组则差异无统计学意义(P>0.05).脑缺血6h组再灌注不同时间点较脑缺血2h组再灌注相应时间点DWI异常信号区相对面积大,ADC值低,TTC失染相对面积大,差异有统计学意义(P<0.05).脑缺血2h组、脑缺血6h组再灌注相对应时间点DWI异常信号区面积与TTC染色失染区面积比较差异无统计学意义(P>0.05). 结论 脑缺血再灌注后可用MRI DWI成像评价脑缺血面积. 相似文献
10.
Linfeng Wu Wu Chen Feng Li Brian R. Morrow Franklin Garcia-Godoy Liang Hong 《Journal of pharmaceutical sciences》2018,107(12):3134-3142
It is important to address the periodontitis-associated bacteria in the residual subgingival plaque after scaling and root planing to successfully treat periodontitis. In this study, we explored the possibility of exploiting the ion pairing/complexation of minocycline, Ca2+, and sulfate/sulfonate-bearing biopolymers to develop an intrapocket delivery system of minocycline as an adjunct to scaling and root planing. Minocycline-calcium-dextran sulfate complex microparticles were synthesized from minocycline, CaCl2, and dextran sulfate. They were characterized using Fourier-transform infrared spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. An in vitro release study was conducted to evaluate the release kinetics of minocycline from these microparticles. Agar disk diffusion assays and biofilm-grown bacteria assays were used to assess antibacterial capability. High loading efficiency (96.98% ± 0.12%) and high loading content (44.69% ± 0.03%) for minocycline were observed for these complex microparticles. Mino-Ca-DS microparticles achieved sustained release of minocycline for at least 9 days at pH 7.4 and 18 days at pH 6.4 in phosphate-buffered saline, respectively. They also demonstrated potent antimicrobial effects against Streptococcus mutans and Aggregatibacter actinomycetemcomitans in agar disk diffusion and biofilm assays. These results suggested that the ion pairing/complexation of minocycline, Ca2+, and sulfonate/sulfate-bearing biopolymers can be exploited to develop complex microparticles as local delivery systems for periodontitis treatment. 相似文献