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Biomedical subjects

M Kuwata

Publications and source records attributed to M Kuwata.

At least 37 records · Page 2Linked to original sources
PubMed1985

State of education.

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Dental Technicians↗
PubMed1984

Acute toxicity study of 1,3,3,5,5-pentaziridino-1-thia-2,4,6-triaza-3,5-diphosp horine-1-oxide (a new antitumor agent with an inorganic ring) in mice, rats and dogs.

In order to study the safety of 1,3,3,5,5-pentaziridino-1-thia-2,4,6-triaza-3,5-diphospho rine-1-oxide (SOAz), a new antitumor agent, acute toxicity studies by intravenous administration were performed in ddY mice, Wistar rats and beagle dogs. The LD50 values in rodents were 325 mg kg-1 for male mice, 450 mg kg-1 for female mice, 100 mg kg-1 for male rats and 82 mg kg-1 for female rats. In dogs, the LD50 values were 12 mg kg-1 for males and 18 mg/kg-1 for females. The dosed animals showed diarrhoea and decreased movement in the three species, and emaciation and loss of body weight in mice and rats. Dogs also showed signs of pneumonia. Histopathological examination revealed bone marrow suppression, atrophy of lymphoid organs and testes, and damage to the digestive tract mucosa in the three species. The main causes of death from single-dose administration were bone marrow aplasia and atrophy of lymphoid tissue in all species, together with gastro-intestinal ulceration in rats and dogs, and infection in mice and dogs.

Animals↗
PubMed1976

Progesterone metabolism in vitro by testes from germ cell-free mice of different ages.

Androgen biosynthesis in vitro by testes from (C57BL X WN)F1-WV/Wn (congenitally germ cell-free) and +/+ (normal) mice of different ages was investigated using [3H]progesterone as substrate. At all ages examined, the seminiferous tubules of the WV/Wn genotype were largely devoid of germ cells. However, the age dependent pattern of progesterone metabolism by germ cell-free testes were similar to that by normal testes. Conversion of progesterone to 5alpha-reduced 17-hydroxy-C21 and C19-steroids such as 3alpha,17alpha-dihydroxy-5alpha-pregnan-20-one, androsterone, 5alpha-androstane-3alpha,17beta-diol and 5alpha-androstane-3beta,17beta-diol was high in testes of 28- and 35-day-old mice of both groups. However, these 5alpha-reduced metabolities were found to be formed in very small amounts or not formed at all in testes of 20-, 120- and 150-day-old mice of both groups, in which conversion of progesterone to 17alpha-hydroxyprogesterone, androstenedione and testosterone was observed. It appears that in the absence of germinal cells, there is a normal increase and reduction of 5alpha-reductase activity in one or more classes of remaining cells during maturation of the testis.

Aging↗