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Biomedical subjects

C L Chen

Publications and source records attributed to C L Chen.

At least 163 records · Page 9Linked to original sources
PubMed1998

High expression of thymidylate synthase is associated with the drug resistance of gastric carcinoma to high dose 5-fluorouracil-based systemic chemotherapy.

BACKGROUND: In the past 4 years, the weekly 24-hour infusion of high dose 5-fluorouracil (5-FU) and leucovorin in the treatment of patients with advanced gastric carcinoma has been prospectively studied at the authors' institution. This has enabled them to explore the possibility that the level of expression of thymidylate synthase (TS), the target enzyme of 5-FU, is related to the drug sensitivity of gastric carcinoma to 5-FU-based chemotherapy. METHODS: To be eligible for this study, patients were required to have received high dose 5-FU and leucovorin chemotherapy (weekly 24-hour infusions of 5-FU, 2,600 mg/m2, and leucovorin, 300 mg/m2) and to have had adequate prechemotherapy gastric carcinoma tissues for immunohistochemical study. TS106 monoclonal antibody was used to detect the expression of TS. A visual scoring system, which ranged from 0 to 3+, was adopted by 2 independent pathologists to semiquantitate the intensity of TS expression. RESULTS: Between 1993 and 1996, a total of 30 patients, 18 men and 12 women, with a median age of 61.5 years, were enrolled. Of these patients, 16 (53.3%) and 14 (46.7%) had high and low expression of TS, respectively. Two of the 16 patients (12.5%) with high expression of TS and 13 of the 14 patients (92.9%) with low expression of TS responded to chemotherapy (P < 0.001, chi-square test). The median overall survival was 10 months for patients with low TS expression and 4 months for patients with high TS expression (P < 0.01, log rank test). CONCLUSIONS: The data from this study suggest that the expression of TS, as determined by immunohistochemistry, is a relatively reliable indicator of whether 5-FU should be used in the treatment of patients with gastric carcinoma.

Adenocarcinoma↗
PubMed1998

Use of spermicide-coated condoms and other risk factors for urinary tract infection caused by Staphylococcus saprophyticus.

BACKGROUND: Staphylococcus saprophyticus is the second most common cause of urinary tract infection (UTI) in young women. Relatively little is known about risk factors for this infection including exposure to vaginal spermicides, which increases the risk of UTI caused by Escherichia coli. PATIENTS AND METHODS: We conducted a case-control study in a large health maintenance organization Case patients were sexually active young women with acute UTIs caused by S saprophyticus identified from computerized laboratory files during 1990 to 1993. Population-based control patients were randomly selected from the organization's enrollment files. Exposures such as sexual activity and contraceptive practice were determined by interview. RESULTS: Of 1299 eligible women, 66% (96 case patients and 629 control patients) were interviewed. Case patients were more often unmarried and were more sexually active. Ninety-nine percent of case patients and 57% of control patients reported previous UTIs. Exposure to any type of condom during the previous year was reported by 53% of case patients and 31% of control patients. Exposure to spermicide-coated condoms during the previous month was associated with a higher risk of UTI (odds ratio [OR], 3.8; 95% confidence interval, 1.4-10.3). The OR for exposure during the previous year ranged from 2.2 (95% confidence interval, 1.0-4.8) for less than once weekly to 6.05 (95% confidence interval, 2.2-16.6) for more than twice weekly. In multivariate analyses, younger age (OR, 0.97 per year), intercourse frequency (OR, 1.2 per weekly episode), prior UTI (OR, 3.3), and frequency of exposure to spermicide-coated condoms (OR, 8.4 for more than once weekly and 10.9 for more than twice weekly) were independent predictors of UTI. Among women exposed to spermicide-coated condoms, 74% of UTIs caused by S saprophyticus were attributable to this exposure. CONCLUSIONS: Spermicide-coated condoms were associated with an increase risk of UTI caused by S saprophyticus. Because sexual activity and spermicide exposure are important risk factors for UTI caused by both S saprophyticus and E coli, it is likely that they share a similar pathogenesis.

Case-Control Studies↗
PubMed1998

Analysis of immunosuppressive proteins in serum of liver-transplanted rats by using an anti-LSF-1 affinity column.

Liver suppressor factor one (LSF-1) is a 40-kDa immunosuppressive protein in the serum of rats 60 days after orthotopic liver transplantation (OLT) between the nonrejector combination of DA donors into PVG recipients. In the present study, the purification of proteins from rat OLT serum taken 60 days after transplantation was performed by affinity chromatography using the anti-LSF-1 polyclonal antibody (pAb). The assessment of column eluates using anti-LSF-1 and OLT serum was studied using rat heart and liver transplantation models. Rejection was not suppressed by the administration of OLT serum in heart or liver allografts. However, heart allografts treated with peak eluates (450 micrograms single shot im, dissolved in Intralipos) taken from the affinity OLT serum survived significantly longer than untreated rats (median = 36.5 days; n = 7 vs 6.5 days; n = 5, respectively, P = 0.011). The same treatment with anti-LSF-1 column eluates also prolonged liver allografts significantly (>200 days) than those in either the untreated group (median = 11 days; n = 7) or those which received only Intralipos (median = 10.5 days; n = 5, P = 0.019). Subsequent analysis of the N-terminal sequences of some of the proteins which were eluted from the affinity column revealed that the homology of a 30-kDa protein was identical to hemoglobin alpha-chain, a 59-kDa protein to granulocyte inhibitory factor, a 70-kDa and a 90-kDa to albumin and its precursor, respectively. Although the specific immunosuppressive component has not been isolated, our results suggested that the anti-LSF-1 column can extract immunosuppressive moiety of LSF-1 from OLT serum.

Animals↗
PubMed1998

An assessment of the effect of driver age on traffic accident involvement using log-linear models.

Statistical models were developed to help understand the relationship between the driver age and several important accident-related factors and circumstances such as injury severity, collision types, average daily traffic (ADT), roadway character, speed ratio, alcohol involvement, and accident location. By using techniques of categorical analysis on the 1994 and 1995 Florida accident database, four long-linear models with three variables in each model with all possible two-way interactions were developed. In order to compare the differences in response between the age groups and a particular accident-related variable, odds multipliers were computed. The effects of age and accident-related factors were examined, and interactions among them were considered. The results indicated significant relationships between the driver age and ADT, injury severity, manner of collision, speed, alcohol involvement, and roadway character. The findings' contribution to the understanding of the effect of age on accident involvement is addressed. A discussion of how log-linear and logit modeling with estimation of 'odds multipliers' may contribute to traffic safety studies is also provided.

Accidents, Traffic↗