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Biomedical subjects

H Sugano

Publications and source records attributed to H Sugano.

At least 163 records · Page 9Linked to original sources
PubMed1981

Effects of methylmercury on zinc-thionein levels of rat liver.

The induction of metallothionein synthesis by administration of methylmercury chloride as studied. A repetitive sc dose of methylmercury chloride to rats in amounts of 10 mg/kg/day for 3 days produced profound hypozincemia and 3-fold increase in hepatic zinc bound to metallothionein by the initial 24 h. The incorporation of 35S-cysteine into hepatic metallothionein was about 4 times larger for rats treated with methylmercury, which was comparable with it for rats treated with cadmium, than for control rats. These results suggest the induction of de novo synthesis of metallothionein by administration of methylmercury, although methylmercury was found to be unable to bind to produced metallothionein both in vivo and in vitro. A stress produced by methylmercury administration appears to be involved in the induction of hepatic zinc-thionein by methylmercury, through its mechanism is not clear.

Animals↗
PubMed1981

Conformation characterization of cyclopentapeptide, L.Val-L.Pro-Gly-L.Val-Gly: a repeating analogue of elastin.

The cyclopentapeptide, L.Val1-L.Pro2-Gly3-L.Val4-Gly5, was synthesized and its conformational characterization was carried out using n.m.r. and theoretical energy calculations. The n.m.r. studies indicated the existence of a cis Val1-Pro2 peptide bond in water and a very strong intramolecular H-bond between the val1 NH and Gly3 C=O groups. This H-bond forms a beta-turn (type II) placing Val4 and Gly5 residues within the turn. Two minimum energy conformations were derived, one of which agrees very well with the solution conformation.

Amino Acid Sequence↗
PubMed1981

Natural history of gastric carcinoma with special reference to the "early cancer" stage: a mitotic index study on original and recurrent carcinomas.

The natural history of gastric carcinoma, especially during the "early cancer" stage, was investigated in terms of chronological changes in the mitotic indices of the carcinoma. Nine cases of gastric carcinoma which recurred after long periods of time were analyzed. In seven cases in which a second operation was performed after 2 approximately 14 years, the mitotic indices of the recurrent carcinomas were about the same as or slightly higher than those of the original ones. On the other hand, in 3 cases in which second operations were done within 2 years, the mitotic indices were lower in the recurrent carcinomas. No general trend toward a change in mitotic indices, relative to either the surface topography or the depth of the stomach wall at the site of the carcinoma, was observed, although there was one exceptional case in which a distinctly elevated mitotic index was obtained at the site of the nodular down-growth of the carcinoma associated with apparent morphological features of progression. In 5 out of 7 cases with lymph node metastasis, the mitotic indices in the metastatic site were slightly higher than in the original carcinoma. The overall impression gained from the present study was of the unchangeability of the cell kinetics of gastric carcinomas during the long early cancer stage, although the results also indicate the gradual or abrupt progression of carcinomas during their natural history. The mechanisms which produced reduction in the growth rates of carcinomas within 2 years after operations are discussed.

Adult↗
PubMed1980

Microinvasive carcinoma of the uterine cervix.

Radical hysterectomy and pelvic lymphadenectomy were performed on 135 patients with Stage I epidermoid carcinoma of the uterine cervix invading less than 5 mm below the basement membrane. These cases were studied to determine the biological behavior of early invasive carcinoma and to establish diagnostic criteria for microinvasive carcinoma of the cervix (Stage IA). None of the 135 patients had metastasis to the parametrial tissue in the final surgical specimen. One (0.9%) of 106 patients with invasion up to 3 mm had lymph node metastasis, while 4 (13.9%) of 29 patients with invasion of 3.1-5 mm had nodal metastasis. Of the 106 patients with invasion up to 3 mm, 25 had confluent invasion. None of the 25 patients had lymph node metastasis. In view of our result, carcinomas with invasion less than 3 mm may be regarded as a separate diagnostic group because of their limited metastatic potential, and may be treated by conservative methods used for carcinoma in situ, even if there is a confluent pattern. For carcinoma with invasion of 3.1-5 mm, more extensive procedures as used for frankly invasive carcinomas are probably necessary.

Carcinoma, Squamous Cell↗
PubMed1980

Induction of gamma-glutamyl transpeptidase activity by dietary phenobarbital in "spontaneous" hepatic tumors of C3H mice.

Biochemical features of spontaneous hepatic tumors in C3H mice were studied histochemically in comparison with those of neoplastic lesions developed in animals fed dietary phenobarbital (PB) continuously or treated with diethylnitrosamine (DEN) during 11 approximately 14 weeks of age. All 42 spontaneous hepatic tumors that developed in control mice by 74 weeks of age were completely negative for gamma-glutamyl transpeptidase (gamma-GTPase) activity. Dietary phenobarbital enhanced hepatic tumorigenesis remarkably, and 32 out of 43 tumors found at 70 weeks showed multifocal gamma-GTPase activity. DEN induced gamma-GTPase-positive islands of hepatocytes, but 12 out of 13 tumors larger than 5 mm in diameter that developed by 60 weeks were gamma-GTPase-negative. The phenomenon of induction of gamma-GTPase activity by PB in "spontaneous" hepatic tumors appears to be important both for elucidating the mechanism of promotion by PB and also for analyzing multisteps of carcinogenesis.

Animals↗
PubMed1980

In vitro carcinogenesis of hepatocytes obtained from acetylaminofluorene-treated rat liver and promotion of their growth by phenobarbital.

The hepatic cells of rats being fed acetylaminofluorene were transferred into culture at various times. Proliferative hepatocytic foci were obtained from animals treated with the carcinogen for more than 9 weeks. These hepatocytic foci became transplantable and capable of growth in soft agar after 4 to 12 months in culture. Phenobarbital markedly enhanced the growth of these hepatocytes in culture.

2-Acetylaminofluorene↗
PubMed1979

Nuclear magnetic resonance studies on a cyclic dodecapeptide analogue of a repeat hexapeptide of tropoelastin: evaluation of secondary structure.

The cyclododecapeptide, (Ala1-Pro2-Gly3-Val4-Gly5-Val6)2, was synthesized and its secondary structure was evaluated from extensive studies in dimethyl sulphoxide, trifluoroethanol and water using NMR methods. A selective decoupling technique in 13C-NMR has been utilized in order to assign the C=O carbon resonances. Temperature dependence of the peptide NH protons and the solvent perturbation of the peptide NH and C=O resonances show the occurrence in all solvents of a beta-turn (a 10-membered H-bond between the Val4 NH and Ala1 C=O) and a gamma-turn, an 11-membered H-bond between the Gly3 NH and the Gly5 C=O; and a possible 14-membered H-bond between the Ala1 NH and the Val4 C=O in dimethyl sulphoxide and trifluoroethanol. These secondary structural features are compared with the linear polyhexapeptide and found the the beta-turn and the gamma-turn are the common conformational features of these peptide systems.

Amino Acid Sequence↗
PubMed1978

Cyclic analog of elastin polyhexapeptide exhibits an inverse temperature transition leading to crystallization.

The cyclic dodecapeptide analog of the linear polyhexapeptide of tropoelastin crystallizes from water on raising of the temperature and thereby demonstrates an inverse temperature transition implying dominant intermolecular hydrophobic interactions. The temperature profiles of turbidity (TP tau) of the cyclododecapeptide are analogous to those of the polyhexapeptide where increases in concentration lead to translations of the profiles to lower temperature without sharpening of the transition. The demonstration of increase in order with increase in temperature for the cyclododecapeptide in water and the similarity of TPtau's lends credence to the view that increases in temperature lead to increases in order, specifically, for the linear polyhexapeptide and, generally, for the precursor protein of the elastic fiber wherein the repeating hexapeptide occurs.

Crystallization↗
PubMed1978

Hydrogen-deuterium substitution and solvent effects on the nitrogen-15 nuclear magnetic resonance of gramicidin S: evaluation of secondary structure.

Complete assignments of nitrogen-15 resonances of gramicidin S have been made in dimethyl sulfoxide, trifluoroethanol, and in a solvent mixture of dimethyl sulfoxide (50%) and methanol (50%). The assignments are achieved by utilizing the secondary structure of gramicidin S, by comparing the nitrogen-15 spectrum of gramicidin S with that of di-N-methylphenylalanine-gramicidin S and by taking into account the distinguishable value of nitrogen-15 chemical shift for valine in model compounds. Deuterium substitution for labile peptide protons was performed to delineate solvent shielded and deshielded peptide nitrogens and to substantiate further the signal assignments. The solvent titration on going from dimethyl sulfoxide to trifluoroethanol was also performed and shown to have a large deshielding effect on the peptide nitrogen whose corresponding peptide carbonyl, within the peptide moiety, was accessible to the trifluroethanol solvent.

Deuterium↗
PubMed1978

Primary malignant melanoma of the vagina: study of four autopsy cases with ultrastructural findings.

Four cases of primary malignant melanoma of the vagina in women aged 23, 44, 51 and 65 years are presented. In these 4 cases, thorough clinical and postmortem examinations ruled out the possibility of a primary melanoma elsewhere. The primary tumors showed exophytic growth with superficial ulceration. Three of the melanomas arose from the middle third of the vagina and one from the upper third. Melanin was visible in sections stained with hematoxylin and eosin in 3 of the tumors. In the other one, the first biopsy failed to reveal melanin. However, the second biopsy performed following irradiation showed abundant melanin pigment. Electron microscopic examination of 3 tumors revealed premelanosomes and melanosomes in the tumor cells, thus confirming the diagnosis. Two neoplasms showed atypical histologic features, and only the presence of melanin enabled us to make diagnosis of malignant melanoma. One melanoma was associated with an adjacent widespread intraepithelial component of superficial spreading type indicating its probable mode of origin. All 4 patients died of widespread metastases within 13 months after initial treatment. These 4 cases, in which clinical diagnosis was confirmed by thorough autopsy, strongly indicate that malignant melanoma can arise directly from the vagina.

Adult↗