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Biomedical subjects

T Tomoyori

Publications and source records attributed to T Tomoyori.

7 recordsLinked to original sources
PubMed1992

An association of acanthosis nigricans and Crouzon syndrome.

An 11-year-old Japanese female having acanthosis nigricans associated with Crouzon syndrome is reported. Crouzon syndrome is a craniostenotic craniofacial malformation associated with premature closure of selective calvarial sutures, exophthalmos, maxillary hypoplasia, and a beak-shaped nose. It is an autosomal dominant inherited disorder. Crouzon syndrome is one of the syndromes which may be associated with acanthosis nigricans. The association of acanthosis nigricans with Crouzon syndrome is assumed to be a rare abnormality, although the true frequency is uncertain. We have reviewed the reported cases of acanthosis nigricans associated with Crouzon syndrome and characteristics were discussed.

Acanthosis Nigricans↗
PubMed1983

Initiation of focal hyperplastic hepatic lesions by transplacental administration of ethylnitrosourea in rats of F1 generation, and no transmission of the effect to F2 and F3 generations.

Administration of ethylnitrosourea (ENU) to pregnant rats in the late stage of gestation has been known to have a mainly neurocarcinogenic action on the progeny. However, when transplacental administration of ENU was combined in postnatal life with a brief dietary exposure to 2-acetylaminofluorene (2-AAF) and a two-thirds partial hepatectomy, numerous focal hyperplastic lesions of gamma-glutamyltranspeptidase (GGT)-positive hepatocytes emerged in the liver of the progeny. On the other hand, rats of F2 generation born of F1 parents and F3 rats born of F2 parents showed no increase in the incidence of hepatic lesions after treatment with the same dietary regimen. It was suggested that direct interaction between fetal liver cells and the carcinogen is important for occurrence of initiated hepatocytes and that the initiation effect on rat liver by ENU does not persist in the descendants of F2 and F3 generations.

2-Acetylaminofluorene↗
PubMed1983

Ultrastructural changes in the bile canaliculi and the lateral surfaces of rat hepatocytes during restorative proliferation.

Ultrastructural changes in the bile canaliculi and the lateral surfaces of rat hepatocytes during regeneration following a two-third partial hepatectomy were studied by transmission and scanning electron microscopy. A marked increase in microvilli, widening of the intercellular spaces, and invagination and indentation of cytoplasmic membranes were seen in the lateral surfaces of hepatocytes during the early period after the operation. The density of the microvilli on the lateral surfaces gradually decreased and intercellular spaces returned to normal within 24 h, whereas the bile canaliculi revealed dilatation and tortuosity with elongation of microvilli. Hepatocytes during mitosis became rounded and showed dispersed microvilli on the sinusoidal surface. The bile canaliculi of mitotic hepatocytes were continuous with those of adjacent hepatocytes. On the 2nd or 3rd day posthepatectomy, hepatic plates became more than one-cell thick and hepatocytes showed occasional acinar arrangements around the dilated bile canalicular lumina. These features gradually returned to normal by one week after the operation. This study revealed unique sequential changes in the bile canaliculi and the lateral surfaces of hepatocytes during regeneration after partial hepatectomy.

Animals↗
PubMed1982

Induction of gamma-glutamyltranspeptidase-positive altered hepatocytic lesions by combination of transplacental-initiation and postanal-selection.

The purpose of this study was to induce in postnatal life the selective growth of altered hepatocytic populations which had been induced in utero by various chemicals. Pregnant rats of a Wistar strain were given a single dose of various chemical carcinogens on the 18th gestational day. From two months postpartum, both the mothers and offspring were given a diet containing 2-acetylamino-fluorene (2-AAF) at a concentration of 0.02% for two weeks. Then, at the end of the first week after the 2-AAF feeding, a two-third partial hepatectomy was performed. All the animals were killed one week after the partial hepatectomy and were examined for the incidence of gamma-glutamyltranspeptidase (GGT)-positive altered hepatocytic foci in the liver. The transplacental administration of not only a hepatic carcinogen, diethylnitrosamine (DEN) but also 7,12-dimethylbenzanthracene (DMBA), which does not usually produce hepatocellular carcinomas in adult rats, induced GGT-positive altered hepatocytes in the liver of the offspring. These hepatocytes grew into grossly visible hyperplastic nodules within a week after the two-third partial hepatectomy. The possible applicability of the transplacental initiation-postnatal selection model for the short-term assay of transplacental carcinogenicity is discussed.

2-Acetylaminofluorene↗