THE MECHANISM OF ACTION OF ALLOXAN ON BLOOD SUGAR

It has been found that an anti-penicillinase immune serum can be produced, in rabbits by the use of purified penicillinase as the antigen. Anti-penicillinase serum is suggested as protection for penicillin from inactivation by penicillinase.     

磷锌颉颃作用机制研究

以水培小麦（ＴｒｉｔｉｃｕｍａｅｓｔｉｖｕｍＬ．）、玉米（ＺｅａｍａｙｓＬ．）为试材,研究了植株及细胞中磷锌间颉颃作用的发生机制。结果表明,高磷抑制了小麦对锌的吸收及向上运转;提高磷水平增强了锌在玉米叶片细胞壁上的固定,从而导致了地上部锌失活。     

促性腺素释放激素(GnRH)的作用机制

促性腺素释放激素(GnRH)通过受体机制对垂体促性腺细胞分泌促卵泡素/促黄体素(FSH/LH)进行调控.在整个细胞信号转导过程中,它与G蛋白结合受体家族Gq/11结合,导致一系列不同信号在细胞内传导,其中细胞内外Ca2+的释放、PKC的激活JNK激活以及小分子G蛋白(Ras)的激活起到了关键性的作用.最终引起细胞内GnRH受体合成、LH/FSH合成和分泌、细胞生长、分化和增殖等生物学效应.     

STUDIES ON THE MECHANISM OF ANTIBACTERIAL ACTION OF 2-METHYL-1,4-NAPHTHOQUINONE

Thioglycolic acid neutralized with sodium carbonate, sodium thioglycolate (Eastman), ethyl mercaptan, cysteine hydrochloride and certain sulfur-containing reducing agents (sodium bisulfite and sodium hydrosulfite) antagonize the antibacterial action of 2-methyl-1,4-naphthoquinone on Escherichia coli in a synthetic medium. Other reducing agents such as stannous chloride, potassium formate and sodium thiosulfate, show no such antagonism. The antibacterial activities of 2-methyl-3-chloro-1,4-naphthoquinone and 2,6-dimethyl-1,4-naphthoquinone are also abolished by excess thioglycolate and cysteine, while that of 2-methyl-3-methoxy-1,4-naphthoquinone with -OCH(3) instead of -Cl or -H in the 3 position on the quinone ring, is not. These findings suggest that the mode of antibacterial action of 2-methyl-1,4-naphthoquinone is by blocking essential enzymes through combination with sulfhydryl groups, or through combination with sulfhydryl groups of essential bacterial metabolites. This combination may take place in the 3-position on the quinone ring. This mode of action is similar to that suggested by other investigators for several antibiotic agents including penicillin. The antibacterial activity of the methoxy quinone, however, even in the presence of sulfhydryl groups, suggests that the foregoing explanation may not be the complete one.     

THE MECHANISM OF THE VIRUCIDAL ACTION OF ASCORBIC ACID

The theoretical yield of H(2)O(2) formed during the oxidation of a virucidal solution of ascorbic acid approximates the virucidal action of an equivalent amount of H(2)O(2). Both the action of ascorbic acid and H(2)O(2) are completely neutralized by catalase. The action of ascorbic acid against influence A virus may therefore be explained as being due to the H(2)O(2) formed during the Cu catalyzed oxidation of ascorbic acid. The observed in vitro virucidal activity of ascorbic acid obviously can not be utilized therapeutically because of the presence of catalase in body tissues.     

HYDROXYUREA: MECHANISM OF ACTION

Acetohydroxamic acid has been identified, by paper chromatography, in the blood of three patients with chronic myelogenous leukemia on hydroxyurea therapy. This suggests that the drug is hydrolyzed yielding hyroxylamine, which then cleaves thioesters, in particular acetyl-coenzyme A.     

雏鸡缺硒病的实验研究 Ⅰ.应用亚硒酸钠治疗雏鸡缺硒病的疗效观察

本文报告应用亚硒酸钠对雏鸡实验性缺硒病的治疗效果. 经对59只呈典型缺硒病症状的雏鸡治疗结果表明:药液浓度为0.01%及0.05%,剂量为0.2及0.5毫升的亚硒酸钠,一次肌肉注射的治疗效果并不明显;浓度为0.05%,剂量为1.0毫升的亚硒酸钠治疗效果显著,治愈率高达88%.病雏于注药后,一般需经2-3天临床症状缓解,经5-8天症状消失,呈临床治愈,但体硒仍处于较低水平,且组织器官的病理学变化也未完全恢复.