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Biomedical subjects

H S Yu

Publications and source records attributed to H S Yu.

At least 145 records · Page 8Linked to original sources
PubMed1987

Effects of cadmium on preimplantation and early postimplantation mouse embryos in vitro with special reference to their trophoblastic invasiveness.

Cadmium chloride, at concentrations of 0.5 or 1 microgram/ml medium, did not affect the trophoblastic invasiveness of mouse embryos treated for 24 hours at 4-cell and morula stages. At higher concentrations of 5 or 10 micrograms/ml medium, most treated embryos in vitro underwent degeneration while a few survivors formed trophoblastic outgrowths with variable areas. Cadmium chloride, at a low concentration of 0.5 microgram/ml medium presented continuously to blastocysts after attachment in vitro, has significantly retarded the trophoblastic outgrowth areas and reduced the number of trophoblastic giant-cell nuclei, though the spreading blastocysts appeared morphologically normal. At higher concentrations of 1 or 5 micrograms/ml medium, cytoplasmic disintegration and detachment of trophoblasts were observed. It is suggested that cadmium may interfere with the cell division and/or the transformation of trophectoderm cells into giant cells, resulting in the retardation of the trophoblastic outgrowths.

Animals↗
PubMed1986

Effects of cadmium on lactate dehydrogenase activities in mouse pre-embryos at various stages.

A decline in LDH activity from four-cell to late blastocyst was demonstrated in pre-embryos from F1 (C57 female X A2G male) female mice. An exposure to 0.5 or 1 microgram/ml cadmium did not affect the in vitro development of the four-cell pre-embryos and morulae or their LDH activities. At 5 or 10 micrograms/ml cadmium, the in vitro development of the treated pre-embryos was affected. Although most of the treated four-cell pre-embryos had proceeded to compaction, they became degenerated 24 h after treatment. The LDH activity of these degenerated pre-embryos was higher than that in the control blastocysts. We propose that cadmium may interfere with the general energy metabolism of the cells. This causes a reduced rate of LDH degradation, leading to a slower decline in LDH activity in cadmium-treated pre-embryos. Failure of some critical biochemical processes after cadmium treatment may ultimately lead to the subsequent degeneration of the treated pre-embryos.

Animals↗
PubMed1986

A study of neurophysiological measurements and various function tests on workers occupationally exposed to vibration.

Seventy male air grinder operators and 72 age-matched control workers were examined. Both groups of workers worked in the warm climate (20 degrees-33 degrees C) of southern Taiwan. None of the workers had symptoms of white fingers. The investigation program comprised: case history, physical examination, determination of maximal motor conduction velocity, proximal and distal sensory conduction velocity (NCV) of the median and ulnar nerves of the right upper extremity, measurement of skin temperature, nail press test, pain threshold and vibratory sense threshold of the upper extremities, and testing of the motor function. The dose-effect correlation between the NCV, various function tests and total operating time (TOT) was performed by multiple stepwise regression analyses. The regression analyses revealed a statistically significant correlation (dose/effect) between "the six NCV, vibratory sense threshold, pain threshold" and "age", as well as "TOT".

Adult↗
PubMed1985

Effects of cadmium on preimplantation mouse embryos in vitro with special reference to their implantation capacity and subsequent development.

A short exposure to 5 or 10 micrograms/ml cadmium chloride for 24 hours disturbed the in vitro development of four-cell and morula-stage embryos of F1 (C57 female X A2G male) mice. Morulae appeared to be less sensitive to cadmium than four-cell embryos. However, the in vitro development of four-cell embryos through compaction to morulae was not affected, though most treated embryos degenerated and decompacted later. It was proposed that cadmium toxicity may not be acting through contact effects on the cell surface and cytoskeleton. It probably interferes with the general energy metabolism of the cells. Although 1 microgram/ml cadmium did not disturb the subsequent in vitro development beyond the implantation stage, a reduced capacity of implantation in vivo was observed after surgical transfer to recipients. In spite of the effects of cadmium salts on the maternal side, the present results suggest that a direct embryotoxic and teratogenic activity of cadmium cannot be excluded.

Abnormalities, Drug-Induced↗