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Biomedical subjects

S F Liu

Publications and source records attributed to S F Liu.

96 records · Page 6Linked to original sources
PubMedDate not supplied

Reductive activation of nitroaromatics and enzyme inhibition: misonidazole and xanthine oxidase.

Reductive activation of misonidazole and misondiazole acetate, a simple derivative, in the presence of xanthine oxidase causes inactivation of the enzyme. The inactivation is not accompanied by binding of the misonidazole to the enzyme. The nitroreductase activity of xanthine oxidase is inhibited as measured by the reduction of 3,5-dinitrobenzonitrile (DNBN). Cysteine does not appear to protect against the enzyme inactivation by misonidazole but, by itself, cysteine has a strong stimulating effect on the reduction of DNBN. The possible significance of these reactions to the toxicity of misonidazole are discussed.

Biotransformation↗
PubMedDate not supplied

Preparation and characterization of hCG-loaded polylactide or poly(lactide-co-glycolide) microspheres using a modified water-in-oil-in-water (w/o/w) emulsion solvent evaporation technique.

A modified w/o/w emulsion solvent evaporation technique was adopted to prepare human Chorionic Gonadotropin (hCG)-loaded polylactide (PLA) or poly(lactide-co-glycolide) (PLGA) microspheres. The effects of preparative parameters, such as stirring rate, polymer MW and concentration, and the composition of both the inner aqueous phase and oil phase etc., on hCG entrapment efficiency and microsphere characteristics were investigated. It was found that by adding 20% glycerol into the inner aqueous phase and 40% acetone into the oil phase, smooth microspheres approximately 1 microm in diameter could be produced with high hCG entrapment efficiency (>90%). In vitro release test showed a burst release of hCG from PLGA (75:25) microspheres, followed by sustained release of 55% hCG over 2 months. The initial hCG burst from PLGA microspheres increased with the glycerol concentration in the inner aqueous phase, but decreased to a low value (ca. 20%) with the addition of acetone into the oil phase, which could be attributed to the associated changes in surface morphology of the microspheres. In vivo experiments demonstrated that a single shot of hCG-loaded PLGA microspheres could produce a comparable antibody response with the inoculation of free hCG four times.

Acetone↗
PubMedDate not supplied

Esophageal cytology and subsequent risk of esophageal cancer. A prospective follow-up study from Linxian, China.

This paper reports a 15-year follow-up study of 12,693 persons in Linxian, China, who were originally screened by esophageal balloon cytology in 1974. The purpose of the study was to evaluate the ability of esophageal balloon cytology to identify individuals at increased risk for developing esophageal cancer. Age, sex and cytologic diagnoses were obtained from the original 1974 records, and information on vital status, cancer experience and potential confounding risk factors was collected from interviews and medical abstracts in 1989. A total of 1,162 incident cases of esophageal cancer and 993 deaths due to esophageal cancer were identified and used in this analysis. The follow-up study showed that the risk of esophageal cancer incidence and mortality increased in parallel with the presumed severity of the 1974 Chinese cytologic diagnoses. After adjusting for potential confounding factors, the relative risks (and 95% confidence intervals) for esophageal cancer incidence, by cytologic diagnosis, were: normal, 1.00; esophagitis, 1.52 (1.07-2.14); hyperplasia, 1.17 (1.02-1.33); dysplasia 1, 1.53 (1.10-2.14); dysplasia 2, 1.89 (1.47-2.41); and suspicious for cancer, 5.77 (3.79-8.80). These results suggest that esophageal balloon cytology, as performed and interpreted in Linxian in 1974, successfully identified individuals at increased risk for esophageal cancer.

Adult↗