Epinephrine: cascade reactions and glycogenolytic effect

The concept of a cascade reaction may serve to indicate the underlying chemical similarity between several biological amplification processes, and as a basis for the formulation of units that emphasize amplification phenomena in reaction kinetics. This approach is discussed in relation to the glycogenolytic effect of epinephrine.     

游离脂肪酸和Tween 20对犊牛和仔鸡离体小肠细胞吸收类胡萝卜素的影响

用犊牛和仔鸡的离体小肠细胞进行β－胡萝卜素和黄体素的体外吸收试验,研究类胡萝卜素浓度、游离脂肪酸和Ｔｗｅｅｎ２０对这两种类胡萝卜素吸收的影响。结果发现：β－胡萝卜素和黄体素的吸收均呈浓度依赖性,且犊牛、仔鸡的β－胡萝卜素吸收率及犊牛的黄体素吸收率保持稳定,为典型的被动扩散模型;游离脂肪酸的添加极显著促进行了类胡萝卜素的吸收,其中油酸的促吸收作用大于硬脂酸,促进β－胡萝卜素和黄体素吸收的最佳硬脂酸与油酸的比例分别为０：１００和１：３;Ｔｗｅｅｎ２０抑制两种离全小肠细胞类胡萝卜素和的吸收,其中对黄体素的抑制作用较大,对照组和Ｔｗｅｅｎ２０各组均无ＶＡ的生成。实验表明同一因素对β－胡萝卜素和黄体素吸收的影响程度不同。     

Interferon: lack of detectable uptake by cells

No interferon, or at most a small fraction of that applied, is taken up by cells during the period of induction of antiviral activity. The lack of detectable adsorption was not influenced either by the concentration of interferon or the volume. The results were similar in both chicken and mouse systems.     

碘对固始公鹅甲状腺激素的影响

以碘作为添加剂,研究了碘对固始公鹅甲状腺激素的影响机理。结果显示:高碘日粮对鹅外周血浆T4、T3水平影响不明显(P>0.05)。而血浆rT3水平则显著升高(P<0.01)。     

Stomatal opening: role of potassium uptake by guard cells

Stomata in isolated epidermal strips open in response to light plus air free of carbon dioxide when the strips are floated on potassium chloride solutions of low concentrations. This opening depends on the stimulation of active accumulation of potassium in quantities sufficient to account for the observed changes in solute potential of the guard cells.     

Langerhans cells: uptake of tritiated thymidine

After irradiation of the skin of the rhesus monkey with ultraviolet light, there is temporary suppression of the proliferating activity of the epidermal cells, followed by some hyperplasia and a striking increase in synthesis of DNA by Langerhans cells. Since Langerhans cells can proliferate, they can no longer be considered to be worn-out melanocytes.     

Intestinal uptake of macromolecules: effect of oral immunization

Animals were orally immunized with horseradish peroxidase and bovine serum albumin, and absorption of these antigens was studied. In comparison with controls, a consistent and significant decrease in peroxidase uptake was noted in both germ-free and conventional rats immunized with peroxidase; a similar decrease in serum albumin uptake was also noted in animals immunized with serum albumin. There was no difference in the uptake of an unrelated macromolecule. These observations suggest that local immunization interferes specifically with the intestinal uptake of macromolecular antigens.     

Avian thyroid: effect of p,p'-DDT on size and activity

Feeding sublethal amounts of p,p'-DDT to pigeons caused an increase in thyroid weight and a reduction in colloid content of the follicles. This may reflect a hyper- or hypo-functioning gland and may be cotnnected with recent reductions in egg shell weights in wild birds. The effect was accompanied by increased liver weight.     

Human T-cell clones from autoimmune thyroid glands: specific recognition of autologous thyroid cells

The thyroid glands of patients with autoimmune diseases such as Graves' disease and certain forms of goiter contain infiltrating activated T lymphocytes and, unlike cells of normal glands, the epithelial follicular cells strongly express histocompatibility antigens of the HLA-DR type. In a study of such autoimmune disorders, the infiltrating T cells from the thyroid glands of two patients with Graves' disease were cloned in mitogen-free interleukin-2 (T-cell growth factor). The clones were expanded and their specificity was tested. Three types of clones were found. One group, of T4 phenotype, specifically recognized autologous thyroid cells. Another, also of T4 phenotype, recognized autologous thyroid or blood cells and thus responded positively in the autologous mixed lymphocyte reaction. Other clones derived from cells that were activated in vivo were of no known specificity. These clones provide a model of a human autoimmune disease and their analysis should clarify mechanisms of pathogenesis and provide clues to abrogating these undesirable immune responses.     

氯己定碘溶液对奶牛乳头消毒效果的研究

为评估氯己定碘溶液对奶牛乳头消毒效果,90头泌乳奶牛被平均分成3个组:Ⅰ组和Ⅱ组奶牛在挤奶前后分别使用氯己定碘溶液和聚维酮碘溶液来对乳头进行药浴消毒,Ⅲ组奶牛不做任何消毒处理。试验持续至12周。结果表明,1)与试验前相比,Ⅰ组和Ⅱ组奶牛日均奶产量和体细胞数(SCC)差异不显著,Ⅲ组奶牛的日均奶产量极显著下降(P0.01),SCC值极显著升高(P0.01);2)持续用药12周后,Ⅰ、Ⅱ组奶牛乳房检出菌株数明显减少,头感染率(33.3%、46.7%)和乳区感染率(11.7%、26.7%)均发生极显著或显著下降(P0.01或P0.05),而Ⅲ组奶牛却发生了显著上升(P0.05);3)持续用药12周后,Ⅰ组奶牛乳房内感染菌的头清除率(60.0%)和乳区清除率(83.3%)显著高于Ⅱ组(44.0%和50.0%),而Ⅲ组奶牛的头清除率和乳区清除率均为0。研究表明,在挤奶前后对奶牛进行乳头消毒可有效预防乳房感染风险,且使用氯己定碘溶液对乳头进行药浴消毒,其功效优于聚维酮碘溶液。     

犊牛睾丸支持细胞的原代培养与鉴定

寻求简便经济的方法分离纯化犊牛睾丸支持细胞,通过不同的方法对支持细胞进行鉴定。采用胶原酶和胰蛋白酶次第消化分离犊牛睾丸支持细胞,5 h后换液,24 h后用Tris-HCl处理除去精原细胞,实现进一步纯化。用Feulgen染色法鉴定支持细胞,用SABC染色法检测支持细胞上Fas-L的表达。结果培养的支持细胞纯度达到90%以上。Feulgen染色后明显可见支持细胞核内的双极小体。SABC染色法检测支持细胞为阳性。建立了培养犊牛睾丸支持细胞的方法,Feulgen染色和Fas-L检测是鉴定支持细胞的有效方法。     

Enzyme from calf thymus degrading the RNA moiety of DNA-RNA Hybrids: effect on DNA-dependent RNA polymerase

An enzyme present in extracts from calf thymus degrades specifically the RNA moiety of DNA-RNA hybrids. Other nucleic acids, such as single- or double-stranded DNA and single- or double-stranded RNA, are not affected to a comparable degree. If prepared free of the hybrid-degrading enzyme, RNA polymerase from calf thymus shows a fivefold increase in activity on denatured DNA as compared to native DNA.     

Insulin-stimulated glucose uptake by subcellular particles from adipose tissue cells

Microsomal particles prepared from isolated rat adipose cells take up D-glucose more rapidly than L-glucose. The rate of D-glucose uptake, but not that of L-glucose, is stimulated by incubation of the intact cells with insulin at concentrations as low as 10 microunits per milliliter before disruption and preparation of the microsomes.     

限量给桑对家蚕丝腺成长规律的影响

对不同指数限制给桑条件下家蚕五龄期丝腺成长规律、营养物质向蚕体组织和丝腺的分配比率、后部丝腺细胞核酸含量及茧质性状等作了比较研究．结果表明：限制给桑家蚕丝腺的成长规律与饱食区相仿，只因限制给桑使营养物质向丝腺的供给量减少，从而使丝物质的合成量较饱食区为少；而对蚕体重增加影响较小．后部丝腺细胞核酸含量的测定结果表明，限制给桑对ＤＮＡ的增加量影响较小，而对ＲＮＡ的增加量影响较大．限制给桑使得五龄经过延长，全茧量、茧层量减少，而茧层生产效率提高．ＲＮＡ合成茧丝蛋白的效率两处理区无明显差异     

Xenon: effect on radiation sensitivity of HeLa cells

HeLa cells, plated onto plastic petri dishes, were exposed to various atmospheres composed of air and carbon dioxide; helium, oxygen, and carbon dioxide; and xenon, oxygen, and carbon dioxide in a pressure vessel. Survival curves with x-rays, 280 kilovolts (peak), show that air and helium have the same effect, but that xenon potentiates x-irradiation to the extent that the dose to produce a given level of survival with xenon is 0.58 of the dose required with air.