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C Wei

Publications and source records attributed to C Wei.

138 records · Page 8Linked to original sources
PubMed1982

Microbial detection of mutagenic nitro-organic compounds in filtrates of coal fly ash.

The presence of mutagenic nitro-organic compounds on coal fly ash was indicated by the greatly reduced microbial mutagenicity of the ash filtrates with nitroreductase-deficient strains of Salmonella typhimurium compared to their corresponding parental strains. Addition of the liver S-9 microsomal enzyme preparation significantly increased the mutagenic activities of the ash extracts. Extracts of fly ash mutagens were prepared with horse serum, dimethyl sulfoxide, or azeotropic benzene/methanol mixture. The data were normalized to net revertants per 10(8) Salmonella typhimurium cells per milligram of ash used. This normalization procedure is essential for interpretation of comparative results. Both four-way and three-way analyses of variance were used to simultaneously evaluate the differences between solvent extracts, fly ash mutagen, S-9 activation, and nitroreductase-deficient strains and their parental strains. Of the three extraction systems tested, benzene/methanol azeotropic mixture was generally found to have the highest extraction power, and horse serum was the lowest. The results show that overall 87.5% (+/- 1.8 SE) of the mutagenic activity of the fly ash was associated with nitro-organic compounds.

Animals↗
PubMed1980

The effects of vitamin C, vitamin B6, vitamin B12, folic acid, riboflavin, and thiamin on the breast milk and maternal status of well-nourished women at 6 months postpartum.

The effects of vitamin supplements and/or diet on the vitamin levels in milk of women were determined at 6 months postpartum. Six subjects consumed a daily supplement (Natalins, Mead-Johnson) in addition to a well-balanced diet--supplemented group, and six subjects consumed only a well-balanced diet--nonsupplemented group. The subjects expressed milk for 3 days at 4-hr intervals, 0, 4, 8, and 12 hr after awakening or taking their vitamin supplement. A 4-day diet record, fasting blood sample, and 24-hr urine samples were collected on each subject at 6 months postpartum. Nutrient intake from diet alone did not differ significantly between the two groups except for riboflavin intake which was significantly higher in the supplemented group. The nutritional status of all women indicated excellent dietary intakes, which vitamin supplementation did not alter significantly. Milk concentration of vitamin B6, vitamin B12, folate, thiamin, riboflavin, and vitamin C, did not differ significntly between groups. Thiamin, vitamin B12, and vitamin B6 concentration in the milk did appear to plateau during the day. Vitamin supplementatin at 6 months postpartum did not affect the breast milk concentration or the nutritional status of well-nourished women.

Ascorbic Acid↗
PubMed1979

Ocular effects in normal rabbits of topically applied labetalol: a combined alpha- and beta-adrenergic antagonist.

The ocular effects in rabbits of topically applied labetalol hydrochloride, a new alpha- and beta-adrenergic receptor blocking agent, were studied. A dose-related reduction in intraocular pressure (IOP) followed treatment with 0.01% to 1% solutions. Labetalol at a 1% concentration had no effect on pupil diameter. The same dose blocked an increase in IOP after water loading but did not significantly alter the coefficient of aqueous outflow facility. Mydriasis induced by phenylephrine hydrochloride was competitively inhibited.

Animals↗
PubMed1977

5'-Terminal capping of RNA by guanylyltransferase from HeLa cell nuclei.

A soluble extract prepared from HeLa cell nuclei has been shown to catalyze the 5'-terminal modification of RNA and synthetic polyribonucleotides to form m7G(5')pppA-and m7G(5')-pppG- structures referred to as caps. The reaction involves the transfer of a GMP moiety from GTP to the 5' end of an RNA molecule containing at least two terminal phosphates. Significantly, neither the beta nor the gamma phosphates of GTP are transferred and polynucleotides with no 5'-terminal phosphate or only one are not acceptors. In the absence of methyl donor, G(5')pppA- and G(5')pppG- structures were synthesized, indicating that methylation is not required for guanylylation. Cap formation was considered to occur by the following mechanism: (see article), in which AdoMet is S-adenosylmethionine, AdoHcy is S-adenosylhomocysteine, and (p)ppN- represents either the original 5' end of an RNA molecule or an internal site to which one or more phosphates were added after processing.

Cell Nucleus↗
PubMedDate not supplied

Cytotoxicity of ammonium metavanadate to cultured bovine alveolar macrophages.

Cytotoxicity of ammonium metavanadate to cultured bovine pulmonary alveolar macrophages was measured by cell viability, inhibition of phagocytosis, and reduction of superoxide-dependent chemiluminescence. The degree of toxicity was dependent on the levels of vanadium, the temperature, and the time of exposure. Thus macrophages exposed to vanadium at 0.01 and 0.1 microgram/ml did not exhibit cytotoxic effects even with up to 24 h of exposure, as measured by cell viability and phagocytic index. Vanadium at 0.5 microgram/ml, however, reduced cell viability to 24% and the phagocytic index to 2% of the control within 8 h of exposure. Exposure to NH4 VO3 (up to 1 microgram vanadium/ml) for short periods of time stimulated phagocytic activity. Vanadium toxicity was also demonstrated in suspension culture at 37 degrees C by chemiluminescence assay. This assay seems to be more sensitive than the conventional viability and phagocytic index tests. Thus, the peak light production by macrophages during zymosan phagocytosis was reduced to 93, 59, and 63% by vanadium at 0.1 microgram/ml exposing for 2, 4, and 8 h, respectively, and to 71, 27, and 24% by vanadium at 1.0 microgram/ml for the same time periods. The phagocytic activity of macrophages as measured by chemiluminescence response was not significantly altered by exposure to either 0.1 or 1.0 microgram vanadium/ml measured during the first 24 h of culture at 4 degrees C.

Animals↗