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Biomedical subjects

Y Fujii

Publications and source records attributed to Y Fujii.

At least 1,081 records · Page 60Linked to original sources
PubMed1985

High mammary carcinogenicity of neutron irradiation in rats and its promotion by prolactin.

The present study was undertaken to assess the mammary carcinogenic effect of low doses of fission and thermal neutrons in female W/Fu rats. Only 2 of 62 (3.2%) rats exposed to various doses of fission radiation alone developed mammary tumors (MT) in a 12-month observation period, whereas 21 of 63 (33.3%) similarly irradiated rats developed MT if further treated with prolactin; the lowest effective dose was 4.1 rad, which contained only 1.7 rad of fission spectrum neutrons with an average energy of 2.0 MeV. The long survival of radiation-initiated potentially malignant cells was suggested by the observation that excess numbers of MT developed in irradiated rats in whom prolactin treatment was started as late as 12 months after irradiation. The negligible contribution of gamma-rays, one component of the reactor radiations, to the rat mammary carcinogenesis was proven by a simulation experiment with 60Co gamma-rays. Thermal neutrons with an average energy of 0.025 eV were less effective than fission neutrons. The rat mammary carcinogenic effects of 180 kVp X-rays, 14.1 MeV fast neutrons, 0.025 eV thermal neutrons and 2.0 MeV fission neutrons were estimated in such a way as to compare the dose of each radiation that gave an MT incidence of 40% of that in irradiated, prolactin-treated rats. The efficiency of fission spectrum neutrons is much higher than those of other radiations; the relative biological effectiveness (RBE) of fission spectrum neutrons was 17.8 against X-rays. Based on these findings, the relevance of animal data to tumor induction in atomic bomb survivors is discussed.

Animals↗
PubMed1985

Protective effects of progesterone and tamoxifen in estrogen-induced mammary carcinogenesis in ovariectomized W/Fu rats.

The protective effect of progesterone or tamoxifen, an antiestrogenic agent, was investigated in estrogen-induced mammary carcinogenesis. Multiple mammary tumors (MT) of tubular or medullary carcinoma type developed at a high rate following prolonged treatment of ovariectomized W/Fu rats with diethylstilbestrol or 17 beta-estradiol. All MTs were located adjacent to the nipple and were slow-growing. The induction rate, multiplicity and size of estrogen-induced MTs were reduced by the simultaneous administration of either progesterone or tamoxifen. The estrogen-induced pituitary tumorigenesis was effectively inhibited by tamoxifen treatment, but it was not affected by progesterone. The results indicated that the inhibitory effect of progesterone or tamoxifen in estrogen-induced carcinogenesis is attributable to interference with the binding of estrogen to the estrogen receptors on the target cells.

Adenoma↗
PubMed1985

Anti-acetylcholine receptor antibody titer with extended thymectomy in myasthenia gravis.

Twenty-four patients with myasthenia gravis of Osserman's generalized type underwent extended thymectomy through a sternal-splitting approach. Their clinical responses to thymectomy and postoperative changes in anti-acetylcholine receptor antibody titers were evaluated. The follow-up time ranged from 1 month to 7 years and 7 months (average, 36 months). Six patients (25%) had remissions and 17 patients (71%) were improved after operation. The preoperative anti-acetylcholine receptor antibody titers dropped significantly after operation (p less than 0.001). The postoperative reduction in these titers correlated with the time course after operation (p less than 0.05). Their postoperative reduction was significantly greater in the six patients having remissions than in the 15 having marked (p less than 0.02) and the six having moderate improvement (p less than 0.005). This study has revealed that anti-acetylcholine receptor antibody titer in plasma declines progressively after thymectomy, and the postoperative reduction of this titer correlates with the clinical effect of thymectomy.

Adolescent↗
PubMed1985

Reaction of nucleic acids bases and their derivatives with peroxodisulfate ion.

Reaction with peroxodisulfate ion was investigated, that is, reaction of 1,3-dimethyluracil, 1,3-dimethylthymine, and caffeine with carbon radicals formed from decarboxylation of carboxylic acids, oxidation of the methyl group at 5-position of thymines, and halogenation of nucleic acids bases and their derivatives with alkali halides.

Caffeine↗
PubMed1985

Effect of Clostridium perfringens alpha toxin on the cardiovascular system of rats.

Clostridium perfringens alpha toxin decreased heart rate, then elevated blood pressure, and finally caused some changes of electrocardiogram readings. The toxin decreased peripheral blood flow before blood pressure started to increase and the blood flow continued to decrease, without any affect on electrocardiogram readings, until the maximal pressure rise caused by the toxin. The toxin caused a rise in blood pressure in a dose-dependent manner. On the other hand, anti-alpha toxin antiserum inhibited both phospholipase C activity and pressor activity. When the toxin was pretreated with cysteine, calcium disodium ethylenediamine tetraacetate and calcium trisodium ethylenetriamine pentaacetate, pressor activity decreased, as well as phospholipase C activity. The results indicate that alpha toxin possesses pressor activity as well as phospholipase C activity.

Animals↗
PubMed1984

Invasive thymoma with myasthenia gravis.

In 261 surgically treated patients with myasthenia gravis (MG), 26 had an invasive thymoma and 49 had a noninvasive thymoma. Invasive thymoma was seen in 41% of thymomatous MG patients older than 40 years of age, and 28% in patients younger than 40 years of age. Of 19 patients who underwent total or subtotal thymothymomectomy accompanied by irradiation (4000 rad), 17 were still alive on an average 6.5 years after surgery. The deterioration of MG by the irradiation was observed in 7 of 20 irradiated cases. Thus, postoperative irradiation is effective but should be done with attention to the deterioration of MG. The prognosis of MG in patients with an invasive thymoma was poorer than that in patients with a noninvasive thymoma.

Adult↗
PubMed1984

Change in kinetic property of M1-type pyruvate kinase from hyperbolic type to sigmoidal type by limited proteolysis with an acid fraction from rabbit liver.

An acid extract of rabbit liver contained M1-type pyruvate kinase inactivating activity, and was separated to three fractions. The optimal inactivation of the enzyme with Fraction II (Mr 42,000) was observed at pH 5.5, and this inactivation was completely prevented by leupeptin and antipain, but not by pepstatin. With Fraction III (Mr 22,000), on the other hand, optimal inactivation of the enzyme was observed at pH 8-9, and was not prevented by these inhibitors. The kinetic properties, with phosphoenolpyruvate, of the enzyme were changed from hyperbolic type to sigmoidal type by the limited proteolysis with Fractions II and III. The subunit molecular weight of the enzyme (57,300) was decreased to 55,800 via 56,400 in the former case and to 56,400 in the latter case.

Animals↗
PubMed1984

Evidence for the neurotransmitter role of norepinephrine in the ventral thalamic nucleus of the guinea pig: localization, uptake and release.

The localization, uptake and release of norepinephrine (NE) by the isolated guinea pig ventral thalamic nucleus (VT) were studied to determine the possible neurotransmitter role of this catecholamine. The NE content in the VT was 356 +/- 24 ng/g wet weight and intraneuronal localization of NE was demonstrated in the VT by histofluorescence. [3H]NE accumulation into the VT slices was about 3 times that of [3H]NE (10(-7) M) in the medium 10 min after incubation. Kinetic analyses indicated 2 components of [3H]NE accumulation, one representing a high (Km1 4 X 10(-7) M and Vmax1 1.5 pmol/mg/10 min) and a low (Km2 1.8 X 10(-6) M and Vmax2 5 pmol/mg/10 min) affinity uptake system. Desmethylimipramine (10(-5) M) reduced the high affinity uptake of [3H]NE by 30% of the control value. Electrical stimulation of the slices increased the efflux of [3H]NE from tissues preloaded with [3H]NE, in a current- and frequency-dependent fashion. The release of [3H]NE induced by stimulation of up to 1 mA was inhibited by tetrodotoxin (10(-6) M) or Ca-free medium containing EGTA (10(-4) M). These findings provide strong evidence for the neurotransmitter role of NE in the VT.

Animals↗
PubMed1984

Tubular adenoma with squamous metaplasia of the sigmoid colon: a case report.

A case of tubular adenoma with squamous metaplasia of the sigmoid colon in a 44-year-old female is reported. The tumor was a pedunculated polyp with a size of 1.2 X 1.7 X 1.7 cm. Histologically, the tumor showed tubular adenoma with focal squamous metaplasia. Borderline atypia was noted in a part of adenoma without squamous metaplasia and squamous component. It is supposed that squamous epithelial polyp, squamous cell carcinoma, adenosquamous carcinoma, and mucoepidermoid carcinoma may be derived from colonic adenoma with squamous metaplasia. Only six cases of the adenoma with squamous metaplasia of the large intestine have been reported previously in the literature.

Adenoma↗