Change in the metabolism and toxic effect of benz(a)pyrene by its metabolites and a series of phenols

Effects of some phenols and polycyclic aromatic hydrocarbon derivatives on benz(a)-pyrene metabolism have been studied in the microsomal system isolated from the mouse embryonic cell cultures. The rate of benz(a)pyrene metabolism was shown to depend on the structure and concentration of the agents added. The toxic effect of benz(a)pyrene was summed up with that of either agent studied (except ionol) added simultaneously to the cell culture.     

Effect of uncoupling agents and benz (a) pyrene metabolites on respiration in L cells and normal mouse embryonal fibroblasts

A method is proposed for a polarografic study of the respiration of cell suspensions obtained from monolayer cultures of L-cells and from normal embryonic fibroblasts of mice (C3HA line). 6-hydroxybenzo(a)pyrene (6-OHBP). The metabolite of the carcinogenic hydrocarbon benzo(a)pyrene, was shown to be a strong uncoupler of of oxidation and phosphorylation of cell suspensions. Its effect was influenced by the presence of calf serum in the incubation media. Possible relationships between the toxic effect of 6-OHBP on monolayer cultures of normal and tumor cells, and its effect on cell energetics are discussed.     

Cryoprecipitates as a source of fibrinogen in treatment of disseminated introvascular coagulation (DIC)

Cryoprecipitates, in addition to containing factor VIII, contain about one third of the fibrinogen in the plasma from which they were derived. This fibrinogen is functional, as established by successfully preparing two congenital hypofibrinogenemics for major surgery by infusing cryoprecipitates. Cryoprecipitates and platelet concentrates are also used for patients with low levels caused by disseminated intravascular coagulation (DIC). We feel that these patients benefit not only from the factor VIII in the cryoprecipitates, but from the fibrinogen, which adds its support to the fibrinogen in platelet infusions, plasma, and whole blood. Such support makes it possible to heparinize such patients more heavily than would be safe without such preparation. The authors report three patients with severe and life-endangering DIC who were heavily heparinized, and supported with cryoprecipitates, as well as other blood fractions. Response to this therapy was excellent.     

Carcinogenicity of benzo-ring derivatives of benzo(a)pyrene on mouse skin

Benzo(a)pyrene (BP) and several benzo-ring derivatives of BP were tested for carcinogenic activity in mice by topical application of each compound once every 2 weeks for 60 weeks. Chronic treatment of C57BL/6J mice with (+/-)-trans-7,8-dihydroxy-7,8-dihydrobenzo(a)pyrene (0.025 to 0.10 micronmole/application) indicated that the dihydrodiol was slightly more active as a complete carcinogen than the parent hydrocarbon BP. 7,8-Dihydroxy-7,8,9,10-tetrahydro-benzo(a)pyrene, a compound related to (+/-)-trans-7,8-dihydroxy-7,8-dihydrobenzo(a)pyrene but which lacks the double bond at position 9,10, was inactive as a carcinogen on mouse skin. These results indicate the importance of the double bond at position 9,10 for the carcinogenic activity of (+/-)-trans-7,8-dihydroxy-7,8-dihydrobenzo(a)pyrene. Chronic treatment of mice with -.4 micronmole of the highly mutagenic (+/-)-7,beta,8alpha-dihydroxy-9alpha, 10alpha-epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene, (+/-)-7beta,8alpha-dihydroxy-9beta, 10beta-epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene, or 9,10-epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene every 2 weeks for 60 weeks resulted in tumor incidences of 0, 8, and 4%, respectively, whereas BP at this dose caused a 100% tumor incidence. The high reactivity of the three epoxides may account for their inactivity or their weak carcinogenic activity on mouse skin.     

火花源原子发射光谱仪的维护

对Baird FSQ火花光谱仪光路系统存在的问题进行了分析研究,并提出具体解决方法.经实施获得了良好的效果,使仪器工作性能基本得以恢复.     

The liver as a source of somatomedin

Somatomedin (Sm) activity (measured by [35S] utake in chick embryo cartilage) was determined in serum samples simultaneously drawn from the hepatic vein, portal vein, femoral artery and demoral vein of seventeen anaesthezied normal adult dogs). A pool of human serum was taken as reference (Sm = 1 U/ml). Sm levels in the peripheral vein of dogs were 0.38 +/- 0.03 U/ml). Mean +/- SEM). Sm activity was greater in the hepatic vein (0.48 U/ml) than in the other vessels (0.36, 0.39, 0.38 U/ml), and the paired differences were significant (P less than 0.002 to P less than 0.05). In three dogs which received b-GH (20 IU/day), the Sm levels were significantly increased after nine days in the femoural vein (P less than 0.05) and in the hepatic vein (P less than 0.05). The validity of the assay is discussed; a possible interference of NEFA in the assay is eliminated. The difference of Sm levels between hepatic and portal veins, related to hepatic flow measured in seven of these dogs, indicate an important production of Sm by the liver.     

Protoplasts of Cosmarium as a potential protein source

Cosmarium turpinii, a fast-growing desmid alga, transforms into protoplasts in 4 h when incubated in a mineral medium + 0.4 M mannitol + 0.5% Cellulysin.     

火花源原子发射光谱仪在现场检测中的应用探讨

火花源原子发射光谱仪现场应用等问题的探讨.