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Biomedical subjects

S R Chen

Publications and source records attributed to S R Chen.

67 records · Page 4Linked to original sources
PubMed1988

Use of all-trans retinoic acid in the treatment of acute promyelocytic leukemia.

Twenty-four patients with acute promyelocytic leukemia (APL) were treated with all-trans retinoic acid (45 to 100 mg/m2/day). Of these, eight cases had been either nonresponsive or resistant to previous chemotherapy; the other 16 cases were previously untreated. All patients attained complete remission without developing bone marrow hypoplasia. Bone marrow suspension cultures were studied in 15 of the 24 patients. Fourteen of these patients had morphological maturation in response to the retinoic acid (1 mumol/L). Chloroacetate esterase and alpha-naphthyl acetate esterase staining as well as electronmicroscopic examination confirmed that retinoic acid-induced cells differentiated to granulocytes with increased functional maturation (as measured by nitroblue tetrazolium reduction, NBT). The single nonresponder to retinoic acid in vitro was resistant to treatment with retinoic acid but attained complete remission after addition of low-dose cytosine arabinoside (ara-C). During the course of therapy, none of the patients showed any abnormalities in the coagulation parameters we measured, suggesting an absence of any subclinical disseminated intravascular coagulation. The only side effects consisted of mild dryness of the lips and skin, with occasional headaches and digestive symptoms. Eight patients have relapsed after 2 to 5 months of complete remission. The others remain in complete remission at 1+ to 11+ months and are still being followed up. We conclude that all-trans retinoic acid is an effective inducer for attaining complete remission in APL.

Adolescent↗
PubMed1986

[Epidemiologic investigation of carcinoma of the esophagus and gastric cardia carcinoma in Nanao County, Guangdong province].

Nanao county, Guangdong province is a high incidence area of carcinoma of esophagus and gastric cardia carcinoma. By retrospective investigation of data in the past 14 years (1970 to 1983), the annual average crude mortality of carcinoma of esophagus and gastric cardia carcinoma was found to be 88.65/100,000, the age adjusted mortality of Chinese population was 82.91/100,000 and that of the world population was 113.09/100,000. The mortality of the male was 100.65/100,000 and of the female was 67.24/100,000 with the ratio of 1.38:1. As regards the relationship between the age and mortality, the highest rate occurs from 50 to 74. A higher mortality was also observed in the population engaged in salt production and fishing. The mortality was higher in the lower elevation areas than in the elevated regions.

Adult↗
PubMed1982

Shearing strengths of recycled direct-bonding brackets.

One hundred twenty freshly extracted human incisor teeth were bonded with several different brands of direct-bonding brackets and tested for retention prior to and after recycling of the brackets by two different commercially available methods. Measurements of shearing strengths were performed to observe any possible changes in the retentive properties of the brackets. The teeth were preconditioned by the application of adhesive material, followed by scaling and pumicing to remove any visible signs of composite. After bonding of the teeth and recording of retentive strengths, the brackets were recycled and the same teeth (after scaling and pumice) were rebonded and tested once more. A decrease in retentive strength was noted in all types of recycled brackets. One type of bracket showed a statistically significant change in strength, depending on the process used in recycling, while the other brackets did not show any difference between the two processes. A control consisting of twenty teeth bonded only once and twenty teeth bonded several times showed no statistically significant change in retention of brackets.

Chemical Phenomena↗
PubMed1980

[Factors contributory to suppressive effect of human suppressor T cells in vitro (author's transl)].

Factors affecting induction and expression of human blood suppressor cells including the concentration of concanavalin A (Con A), the exposure time of lymphocytes to Con A, and the ratio of suppressor cells and responder cells, were studied in Con A induced lymphocyte transformation by both the tube method and the microplate method. The most optimal concentration of Con A for suppressor cell induction was found to be 40 micrograms/ml (tube method) or 40 micrograms/well (microplate method). However, a range from 10 micrograms to 40 micrograms/ml or 10 micrograms to 80 micrograms/well was almost equally effective. At least 16 hr of incubation with Con A was required for generation of suppressor cells, but 2 hr incubation with Con A followed by 22 hr without Con A was also effective. As far as the effect of the ratio of suppressor cells to responder cells on the expression of suppressive effect is concerned, 1:1 was enough but 2:1 was more effective. There was no marked difference in results obtained by both methods. However, the microplate method is simple, quick and economic and, therefore, is highly recommended in our country.

Concanavalin A↗