Effect of urethane (ethyl carbamate) on the mitosis of phytohaemagglutinin stimulated human lymphocytesin vitro

Summary The action of urethane at concentrations between 10^–1 and 10^–8 M on the rate of mitosis of phytohaemagglutinin-stimulated human lymphocytes in culture has been investigated. At 10^–1M urethane is cytotoxic, at all other concentrations tested it has some inhibitory activity except at 10^–5M and 10^–6M where it stimulates mitosis. These results are discussed in relation to previously reported data and compared with the action of hydroxyurea in the same system.I wish to thank the Smith Kline and French Foundation for financial support and Mrs. B. Haynes and Miss C. Watson for technical assistance.     

Immunomodulating effect of autohaemotherapy (a literature review)

An analysis is presented of experimental and clinical data from different authors on the stimulating effect of autohaemotherapy with regard to the immunological reactivity of humans and animals as well as in vitro experiments with lymphocytes. Erythrolysate has been found to exert a more powerful effect than intact erythrocytes. The stimulating effect of autohaemotherapy on both irradiated and non-irradiated animals manifests itself in an increase in resistance to infection (increased LD50 in experimental infection), enhanced production of antibodies to microbial and tissue antigens and activated functioning of cell-mediated immune defence mechanisms. The favourable influences on radioresistance and the antitumour effect of authohaemotherapy are described. Induced desensitization plays an important part in the mechanism of action of autohaemotherapy. The administration of large doses of erythrocytes or of erythrolysate results in immunosuppression. Autohaemotherapy does not cause side effects and is feasible both on an in-and out-patient basis.     

Synthesis and properties of vinyl carbamate epoxide, a possible ultimate electrophilic and carcinogenic metabolite of vinyl carbamate and ethyl carbamate

Vinyl carbamate reacted with dimethyldioxirane in dry acetone to give a high yield of pure crystalline vinyl carbamate epoxide. This epoxide was characterized by its NMR and MS spectra and elementary analysis. It is unstable at room temperature and has a half-life in water solution of approximately 32 minutes. It reacts with adenosine to form 1,N6-ethenoadenosine and more of this etheno nucleoside was found in hydrolysates of hepatic RNA of male mice injected i.p. with the epoxide than with vinyl carbamate. Tests with Salmonella typhimurium TA1535 showed that this epoxide is a strong direct mutagen. It is also more toxic in the mouse than vinyl carbamate. Studies on the carcinogenicity of this epoxide are in progress.     

Endothelium function in ischemia-reperfusion (a literature review)

Endothelium was shown to be one of the most hypoxia-tolerant mammalian cell types and to be injured in ischemia to a lesser extent than other cells. Alteration in the endothelial function during hypoxia and ischemia protects the organs against ischemic injury. Postischemic reperfusion contributes to endothelial dysfunction and initiates the reperfusion injury. Some data show ischemia/reperfusion to cause a systemic alteration of endothelial function in remote organs.     

The interaction of ( 3 H)ethyl carbamate with nucleic acids of regenerating mouse liver

The binding of [³H]urethane to liver DNA and RNA has been examined in partially hepatectomised and intact male Crackenbush mice. A single dose of [³H]urethane (50 μCi) was given to non-hepatectomised mice (group A) and to 3 groups of partially hepatectomised mice at 18 (B), 28 (C) and 38 (D) hours postoperatively, respectively. The binding was examined over the subsequent 16 h. The maximum levels of binding to DNA declined in the order, group A > B > C > D, although the binding to DNA persisted longest in group B. The binding to RNA was greater in groups B, C and D than in group A. Neither the restoration of liver mass nor an alteration in the metabolism of urethane appeared to account for the different levels of binding. In normal and partially hepatectomised mice a single dose of urethane (20 mg) was followed by an inhibition of mitosis and of the incorporation of [³H]thymidine into liver DNA and of [³H]uridine into liver RNA.     

发酵酒中氨基甲酸乙酯的研究进展

对发酵酒中氨基甲酸乙酯（Ethyl carbamate,EC）的致癌机理、检测方法、形成机制、前驱物质及控制方法等方面进行综述。阐述目前研究进展的同时,对存在问题进行分析并提出解决设想及应用展望。氨基甲酸乙酯可由自然反应及添加前驱物质两种方式形成,其致癌机理是通过两种不同途径破坏DNA结构。通常情况,主要通过减少前体物质的添加和形成抑制氨基甲酸乙酯的生成。氨基甲酸乙酯的通用检测方法为色谱与不同检测器结合使用或色谱与质谱联用,其中,检测前的样品前处理有液液萃取,固相萃取等不同形式。目前,我国检测控制工作虽然已经取得一定进展,但是检测方法不够经济有效,控制方法不能够普遍应用。关于控制方法的最新研究中,基因工程技术与系统生物技术的相关应用纳入进程,后基因组研究和蛋白质学等对基因的应用改造处于探索阶段。随着关于氨基甲酸乙酯的危害、形成机理等方面的研究不断深入,不同机制的控制方法不断出现。EC的处理逐步进入更加完善的状态。     

The concentration of ethyl carbamate in commercial ume (Prunus mume) liqueur products and a method of reducing it

The ethyl carbamate concentration of commercial ume liqueur products was studied, and a method of reducing it was examined from the viewpoint of antioxidation. The average ethyl carbamate concentration across 38 ume liqueur products was 0.12 mg/l (0.02-0.33 mg/l). When potassium metabisulfite was added to a concentration of 0-1,000 ppm during production, the generation of ethyl carbamate was reduced in a concentration-dependent manner, but when the amount of potassium metabisulfite added was below the maximum level allowed under the Japanese Food Sanitation Act, the reduction was only 27%. When ume liqueurs were produced under deoxygenated conditions created using an oxygen absorber, the ethyl carbamate concentration was reduced by up to 47% as compared with the control group, probably due mainly to a reduction in free hydrogen cyanide. When ume liqueur was produced in an oxygen atmosphere, the ethyl carbamate concentration increased by up to 50% as compared with the control group. Thus, oxygen may be involved in the generation of ethyl carbamate in ume liqueur production.