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531.
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533.
Rosette-forming ability of human lymphocytes was tested before and after their sensitization with isoimmune sera against histocompatibility antigens. Anti-HLA sera inhibited the ability of T- and B- lymphocyteè to form rosettes. Some sera inhibited rosette formation mostly of B-lymphocytes; they also possessed marked capacity to react with B-lymphocytes population in prolonged lymphotoxic tests.  相似文献   
534.
It was shown in experiments on rats that burn injury is followed by microcirculatory disturbances, hemoconcentration and increasing blood viscosity that is especially pronounced in the vessels with low blood pressure. The microcirculatory changes in the mesentery correlated with the in vitro investigated dynamic viscosity and blood composition. The disturbances were more pronounced after severe burn followed by a mortal shock than after moderate burn without fatal consequences. This investigation confirms great importance of hemorheological changes and microcirculatory disturbances in the early period of burn disease.  相似文献   
535.
陕北黄土区雨季后山地枣林土壤水分动态变化研究   总被引:1,自引:0,他引:1  
选取陕北延川县齐家山红枣试验基地枣林地、苹果林地和撂荒草地为研究对象进行土壤水分动态变化研究,结果表明:①不同坡位、不同坡向和不同整地方式的枣林地土壤水分存在显著差异;其中,研究区下坡位土壤水分最高,为14.19%;阴坡土壤水分最高,为14.19%;水平阶整地枣林土壤水分显著高于原状坡。②研究区不同植被类型间土壤水分垂直变化趋势基本一致。枣林地土壤水分最高,为11.49%;不同植被类型0~100 cm土壤贮水量依次表现为枣林地(144.76 mm) > 苹果林地(124.19 mm) > 撂荒草地(72.20 mm)。③不同植被类型土壤贮水亏缺度存在差异。雨季前,0~20 cm土层亏缺度最小,平均亏缺度表现为撂荒草地 > 枣林 > 苹果林;雨季后,土壤水分亏缺度表现为撂荒草地 > 苹果 > 枣林,除枣林地外均高于雨季前土壤水分亏缺度。④雨季后,研究区3种植被类型0~20 cm土层土壤水分亏缺加剧;20~100 cm土层中,枣林土壤贮水补偿度为正值,土壤水分得到补偿,但最高仅为22.95%,枣林土壤水分仍处于亏缺状态并未完全恢复;苹果林地土壤贮水补偿度则为负值,表明土壤水分亏缺进一步加剧;撂荒草地土壤水分补偿度基本维持在0左右,土壤水分亏缺没有持续恶化。  相似文献   
536.
为明确药用植物委陵菜与其同属植物星毛委陵菜在不同基原之间的代谢差异,更有效的利用药用植物资源。基于气相色谱与质谱联用技术对两药用植物间的小分子初生代谢物进行非靶向代谢组学分析,利用主成分分析和偏最小二乘法分析,寻找可区分两物种的差异代谢物以及在初生代谢途径上的差异。结果:利用GC-MS在两植物中共检测到134个色谱峰,通过与数据库比对,共鉴定出43种初生代谢产物。PCA分析结果显示代谢物在委陵菜和星毛委陵菜间的分布有较大的差异;采用OPLS-DA筛选获得导致2物种区分的差异代谢物共33种,两物种在半乳糖代谢、淀粉和蔗糖代谢、氨酰生物合成、氨基糖和核苷酸糖代谢和果糖和甘露糖代谢途径有显著的差异。委陵菜和星毛委陵菜的初生代谢方面存在较大差异,虽然两植物来源于同科同属植物,但是星毛委陵菜不适合代替委陵菜作为药材使用。  相似文献   
537.
Abstract. Lysozymes are widely distributed in many organisms as one of the components of defence mechanisms. In herbivores, when nitrogen is not contained in sufficient amounts in the diet, bacteria lysed by stomach lysozymes are used as sources of nitrogen. In ruminants, lysozymes function as digestive enzymes in the true stomach. A convergence of amino acid sequence has been shown between the stomach lysozymes of different ruminants, and similar lysozymes have recently been reported in the gut or salivary gland of insects. In this mini review, the enzymatic and ecological functions of lysozymes in insects, particularly in termites, are introduced, together with future studies that are needed in this field.  相似文献   
538.
Kinetics of the content of nonheme iron-sulphur-containing (iron-sulphur) proteins, free radicals of electron-transport mitochondrial system, as well as of microsome terminal oxidase cytochrome P-450 is studied in the liver of rats at early stages of carcinogenesis and in the process of tumour growth induced by intratracheal administration of various benz(a)pyrene doses. It is found that the content of iron-sulphur proteins increases after the first administration, then it falls against a background of higher concentration of free radicals. A degree of pronounced changes in the content of the studied iron-sulphur proteins correlates with carcinogen dose. The cytochrome P-450 content is lowered for almost the whole period of carcinogen administration. In later periods animals with morphologically determinable pretumour changes exhibit a much higher content of iron-sulphur proteins, somewhat increased concentration of free radicals and a tendency to an increased level of cytochrome P-450. The appearance and growth of malignant tumours is followed by a considerable decrease in the content of iron-sulphur proteins and cytochrome P-450. On the basis of the results obtained it is supposed that the changes in the content of iron-sulphur proteins in the rat liver is the earliest and most pronounced reaction which depends on the benz(a)pyrene dose and may be of prognostic significance.  相似文献   
539.
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