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Biomedical subjects

M C Chang

Publications and source records attributed to M C Chang.

At least 199 records · Page 11Linked to original sources
PubMed1987

Liver alcohol and aldehyde dehydrogenase isoenzymes in Chinese.

Alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) isoenzyme phenotypes were determined in 71 autopsy liver specimens by agarose isoelectric focusing and starch gel electrophoresis, respectively. Ninety percent of the livers examined exhibited a pH-optimum for ethanol oxidation at pH 8.5, instead of 10.5 which is usual among Caucasians. The homozygous ADH2 2-2 phenotype was found to be 59%, and the heterozygous ADH2 2-1 phenotype, 31%. The remaining 10% of the livers, exhibiting a pH-optimum at 10.5, were homozygous ADH2 1-1 phenotype. Accordingly, the gene frequencies of the alleles ADH2(2) and ADH2(1) were calculated to be 0.75 and 0.25, respectively. Fifty-eight percent of the 71 livers examined possessed both the activities of ALDH I and ALDH II isoenzymes, whereas 42% lacked the ALDH I activity. The implications of these distributions of liver ADH and ALDH isoenzyme patterns among Orientals for ethanol elimination, alcohol sensitivity and alcoholism are discussed.

Adult↗
PubMed1986

Construction of a host-vector system in Candida maltosa by using an ARS site isolated from its genome.

To construct a host-vector system in an n-alkane-assimilating yeast, Candida maltosa, the isolation of an ARS site from its genome which replicates autonomously in C. maltosa was attempted. Leu- mutants of C. maltosa were transformed with a gene library prepared by using YEp13 (LEU2+) as a vector, and Leu+ transformants were obtained at a high frequency. A plasmid named pCS1 was isolated from the recipient cells. pCS1 contained a 6.3-kilobase (kb) fragment of the C. maltosa genome, and a 3.8-kb fragment with ARS activity was subcloned and designated the TRA (transformation ability) region. Vectors (pTRA1 and pTRA11) for C. maltosa J288 were constructed that contained this 3.8-kb fragment, pBR322, and the LEU2 gene of Saccharomyces cerevisiae. Transformation of C. maltosa J288 with these plasmids was successful by both spheroplast and lithium acetate methods. Southern blot analysis suggested that the copy number of pTRA1 in C. maltosa was between 10 and 20, and it was stably maintained during growth without selective pressure in the medium. It was also found that these vectors could transform S. cerevisiae leu2- to LEU2+, suggesting that the TRA region contained an ARS site(s) that was specific not only for C. maltosa but also for S. cerevisiae.

Candida↗
PubMed1985

The effects of temperature- and oxygen-acclimation on phospholipids of goldfish (Carassius auratus L.) brain microsomes.

Brain microsome phospholipids and their acyl groups, from temperature and oxygen acclimated goldfish, were investigated. At the lower acclimation temperature (5C) the proportion of ethanolamine- to choline-glycerophosphatides (GPE/GPC) was increased, and the proportion of phosphatidal ethanolamine value decreased. A rise in the n-6/n-3 fatty acyl group also occurred in cold acclimation. Irrespective of acclimation temperature, 25 degrees C or 5 degrees C, a partial replacement of GPC by GPE occurred when the concentration of oxygen was increased; conversely the GPE/GPC ratio decreased at the hypoxic level. The plasmalogen GPE content increased as the oxygen concentration was raised. A rise in the n-6/n-3 ratio, for ethanolamine glycerophosphatides and phosphatidyl choline, occurred when the oxygen concentration was increased (hypoxia to hyperoxia). It is concluded that the lipid alterations associated with thermal acclimation are, in part, attributable to the concomitant change in oxygen concentration.

Acclimatization↗
PubMed1985

The effect of temperature- and oxygen-acclimation on phospholipids of goldfish (Carassius auratus L.) brain mitochondria.

Goldfish (Carassius auratus L.) were temperature- and oxygen-acclimated and the composition of the phospholipids and their acyl groups in brain mitochondria was determined. The proportion of ethanolamine to choline phospholipid was greater while the plasmenyl ethanolamine value (P-GPE/D- + P-GPE) was lower at the low acclimation temperature. For the ethanolamine glycerophospholipids, a rise in the ratio n-6/n-3 fatty acyl groups occurred with cold acclimation. No significant change in the ratio was exhibited by phosphatidyl choline. When the oxygen level was increased, at either acclimation temperature, a rise in the GPE/GPC ratio and the plasmenyl ethanolamine value resulted. The n-6/n-3 ratio was generally increased for the ethanolamine classes when the oxygen concentration was raised. The possible significance of these changes is discussed.

Acclimatization↗
PubMed1985

Inhibition of fertilization in the rabbit long after injection of Depo-Provera.

Mature female rabbits were given subcutaneous injections of 20 or 50 mg Depo-Provera (Upjohn Company, Kalamazoo, MI) (medroxyprogesterone acetate). Ovulation by mating was inhibited for 40 to 65 days. Although ovulation could be induced by injection of human chorionic gonadotropin, fertilization of eggs failed in all females 15 to 83 days after treatment. When treated and untreated females were inseminated with a definite number of spermatozoa and given human chorionic gonadotropin, fertilized eggs and spermatozoa were found in the oviducts of untreated, but not in the treated, females. Although spermatozoa were found in the uterine horns of treated rabbits, the number was much lower than in the untreated females. It is concluded that long after injection of Depo-Provera, not only was ovulation inhibited, but also fertilization, due to the suppression of sperm transport in the female tracts. The effects of progestins on various aspects of animal reproduction are discussed, stressing the effectiveness and efficiency of their contraception.

Animals↗
PubMed1984

Social and economic change, intergenerational relationships, and family formation in Taiwan.

This paper examines the influence of social change and economic growth on intergenerational relationships and the formation of families in Taiwan. Using data from two island-wide surveys in 1973 and 1980, the analysis shows that, as expected, social change has been accompanied by rapid changes in family structure and relationships, including the spread of schooling, the employment of young people outside the family, increasing separation of the residences of parents and children before and after marriage, growing independence of young people, and increases in premarital sex and pregnancies. The position of a family in the social structure also influences the way young people interact with their parents and form their own families: women with educated fathers have more nonfamilial experiences than others, and farm origins tend to exert a traditional influence on the life course. Finally, experiences early in the life course have important ramifications for later behavior and transitions.

Adult↗
PubMed1983

Fate of rabbit eggs transferred asynchronously to the oviducts or uteri of oestradiol-treated recipients after ovulation.

The effectiveness of 200 micrograms oestradiol benzoate (ODB) given at various times following ovulation, to overcome a 3-4-day difference in ovulation times between donor and recipient was examined. In approximately half of the recipients in which the interval from the administration of human chorionic gonadotrophin (hCG) to ODB was 2 days, some of the eggs implanted. With a 4-day interval, however, neither implantations nor degenerate blastocysts were found at autopsy on days 11 or 12 in recipients of either tubal or uterine eggs.

Animals↗
PubMed1983

Maintenance of pregnancy in rabbits treated with long-lasting progestins.

Fertilized eggs from rabbits 1 or 2.5 days after insemination were transferred to the oviduct or uterine horn of recipients that had received a single subcutaneous injection of 20 or 30 mg of one of seven long-acting progestins. The rabbits were observed daily, and the number of implantation sites was determined 10 or 11 days after egg transfer. No implantation sites were recorded in the recipient does treated with progesterone or ZK-5623 (Schering AG, Berlin, West Germany), a nor-steroid compound. Thirty-nine percent and 51% of the transferred eggs implanted in the recipient does treated with ZK-5410 (Schering AG) and chloromadinone acetate (Eli Lilly & Company, Indianapolis, IN), respectively. However, most of the pregnant animals aborted 14 to 20 days after egg transfer. The pregnancy was either maintained to term or was prolonged beyond the normal gestation length in the does treated with other compounds, ZK-53915, ZK-9349 (Schering AG) or Depo-Provera (Upjohn Company, Kalamazoo, MI). The young delivered after a subcutaneous injection of 17 beta-estradiol and oxytocin were found normal and active.

Animals↗