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Biomedical subjects

S Adachi

Publications and source records attributed to S Adachi.

At least 415 records · Page 23Linked to original sources
PubMed1986

Carcinogenic effects of a mixture of nitropyrenes in F344 rats following its repeated oral administrations.

The carcinogenic effects of a mixture of 1-nitropyrene and three dinitropyrenes (1,3-, 1,6- and 1,8-dinitropyrene) were investigated in rats. Female F344/Jcl rats were given one of three doses (5, 10 and 20 mg/kg body weight) of the mixture by repeated intragastric instillations twice a week for 55 weeks, and then autopsied 49 weeks later. Mammary adenocarcinomas were induced in rats of all the three experimental groups dose-dependently, while no adenocarcinoma was induced in the control rats which were given only vehicle. Clitoral gland tumors, most of which were diagnosed as squamous cell carcinomas, were also commonly observed in the NP-treated rats in a dose-dependent way. In addition, high incidences of mononuclear cell leukemias were noted in the NP-treated rats. Other tumors were frequently induced in the uterus and endocrine organs, such as the pituitary, adrenal, and thyroid glands. However, the incidences of these tumors were almost equal in both the control and NP-treated groups. The results of the present study indicated the potential carcinogenic activities of nitropyrene compounds in female rats when they were treated by oral route, and suggest that the oral intake of nitropyrene compounds might be related to the incidence of cancer in humans.

Administration, Oral↗
PubMed1985

Difference of lectin binding sites of secretory granules between normal pituitary and adenoma cells.

Electron-immunocytochemical staining with lectin (concanavalin A: Con A) binding sites analysis was applied to study secretory granules of human pituitary adenomas and surrounding normal pituitary tissue using post-embedded serial ultrathin sections. Twelve cases of human pituitary adenoma and three specimens of normal pituitary tissue surrounding adenomas were studied: the cases were operated on between 1982 and 1984. The tumors consisted of four prolactin (PRL)-, six growth hormone (GH)-, and two adrenocorticotropic hormone (ACTH)-producing adenomas. In parallel with the detection of Con A binding sites of secretory granules, their secreting hormones were characterized electron-microscopically with the immunocytochemical horseradish peroxidase (HRP) labeling using the avidin-biotin technique. The two cases of ACTH-producing adenomas showed either weak or negative reactions with Con A on secretory granules, while normal ACTH-producing pituitary cells showed strong reactions with Con A on every secretory granule observed. Large secretory granules of PRL- or GH-producing cells showed negative reactions with Con A both in the pituitary adenoma and normal pituitary, while some small granulated or sparsely granulated adenoma cells also showed strong reactions with Con A. The complexity of human pituitary adenomas is illustrated as well as the difference in biochemical structure of normal pituitary cells and pituitary adenoma cells secreting the same specific hormone.

Adenoma↗
PubMed1985

Study of bilirubin metabolism by high-performance liquid chromatography: stability of bilirubin glucuronides.

The stabilities of bilirubin (BR) glucuronide, monoglucuronide (BMG), and diglucuronide (BDG) were studied under various conditions by HPLC. In aqueous media, BMG showed a pronounced lability and was easily transformed into equimolar BDG and BR. It was proved by direct analysis of tetrapyrrole isomers that BDG and BR were formed from dipyrrole exchange of BMG molecules. All reducing agents examined (sodium ascorbate, cysteine, GSH, dithiothreitol, NADH, and NADPH) suppressed the transformation of BMG into BDG and BR. Bovine serum albumin and rat liver cytosol fractions also stabilized BMG strongly. BDG was fairly stable in aqueous media as compared with BMG. When BMG was incubated both with and without liver plasma membranes (N2 fraction) from Wistar rats, the formation rates of BDG and BR in both incubation mixtures were exactly the same. The composition of BDG and BR isomers was the same in both mixtures. Also, heat denaturation of the plasma membranes did not affect formation rates. Moreover, the reaction was completely inhibited by sodium ascorbate. These findings indicate that rat liver plasma membranes have no enzyme activity for BDG formation from BMG.

Animals↗
PubMed1985

Identification of maturation-inducing steroid in a teleost, the amago salmon (Oncorhynchus rhodurus).

Maturation-inducing steroid in amago salmon (Oncorhynchus rhodurus) has been identified from media in which immature but fully grown folliculated oocytes of amago salmon had been incubated for 18-24 hr with chum salmon gonadotropin (SGA). The maturation-inducing (MI) activity of residues at various steps of purification was assessed by an in vitro germinal vesicle breakdown (GVBD) assay based on fully grown prophase-arrested folliculated oocytes of amago salmon. Ether extracts of the media from these incubates showed high MI activity. Yolk and oil droplets were removed from the ether extract by partition with equal volumes of 50% methanol and n-hexane. MI activity was found only in the 50% methanol phase. The 50% methanol phase was then fractionated (20 separate fractions) by reversed-phase high-performance liquid chromatography. MI activity was found only in fraction 10 which had a retention time coinciding exactly with 17 alpha,20 beta-dihydroxy-4-pregnen-3-one (17 alpha,20 beta-diOHprog). The purity and final characterization of the residues of fraction 10 were further confirmed by thin-layer chromatography and mass spectrometry with authentic 17 alpha,20 beta-diOHprog standard. The present study, together with our previous findings that in amago salmon 17 alpha,20 beta-diOHprog is the most potent steroid for the induction of oocyte maturation in vitro and is present at high concentrations in the plasma only around the time of oocyte maturation, indicates that 17 alpha,20 beta-diOHprog is the major naturally occurring maturation-inducing steroid in this species.

Animals↗
PubMed1985

Use of the balloon catheter for distal occlusion of the aorta in prosthetic replacement of aortic arch aneurysms.

A balloon catheter was utilized to occlude the distal aorta during prosthetic replacement of an aortic arch aneurysm in 4 consecutive patients under conditions of separate cerebral and peripheral perfusion and deep hypothermia. All patients survived the procedure, and 3 were doing well 1 to 1.5 years following operation. One patient sustained a cerebral infarction and recovered with some sequent disability. The use of a balloon occlusion catheter allowed us to perform the operation through a median sternotomy only, and eliminated the procedure of pulmonary dissection for distal clamping and the risk of emboli. In addition, its use provided a relatively bloodless field and sufficient protection for organs in the lower body through adequate perfusion, even when their function was poor or when the distal anastomosis was prolonged. We realized improved surgical results in the treatment of aneurysms of the aortic arch.

Aged↗