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Biomedical subjects

T Matsui

Publications and source records attributed to T Matsui.

At least 1,081 records · Page 60Linked to original sources
PubMed1979

Metabolism of thyrotropin releasing hormone in brain extracts. Isolation and characterization of an imidopeptidase for histidylprolineamide.

An extract of porcine brain acetone powder incubated with thyrotropin-releasing hormone (TRH; pGlu-His-ProNH2) produces acid TRH (pGlu-His-Pro), histidine, and prolineamide. Fractionation of the brain extract by DEAE-cellulose chromatography produces three protein fractions which metabolize TRH. The activity of these fractions was characterized using TRH with a 3H-label on the histidine or proline as well as [His-3H]His-ProNH2. Fraction I contains pyroglutamate aminopeptidase and Fraction II contains TRH deamidase. Fraction III was found to contain a previously unrecognized enzyme which cleaves His-ProNH2 to histidine and proline. The histidylprolineamide imidopeptidase has been characterized. A competition study using a variety of compounds containing histidine or proline suggests that the best substrates for the imidopeptidase contain a free alpha-amino group on histidine and a blocked carboxyl group on proline, as is found in His-ProNH2. A survey of a variety of polypeptide hormones indicates that many of them inhibit the imidopeptidase activity. A kinetic study of the inhibition of the enzyme by adrenocorticotropic hormone (1-24) shows that the inhibition by polypeptide hormones is noncompetitive. We hypothesize that pituitary hormones may stimulate the production of (cyclo)-His-Pro by inhibiting alternate routes of TRH metabolism.

Animals↗
PubMed1979

Vascular anatomy of flexor tendons. I. Vincular system and blood supply of the profundus tendon in the digital sheath.

The detailed blood supply of the flexor tendons in the digital canal was studied in 35 fresh human hands by means of an India ink-latex vascular injection technique. The specimens were examined by first exposing the pulley system, followed by examination of the intact tendon which had been rendered transparent by immersion in a solution of tributyl and tricresyl phosphate. Five annular and three cruciform pulleys were shown. There were five types of long vincula to the profundus (VLP) and three types of long vincula to the superficialis (VLS). The vincular systems of index and little fingers were symmetrical. Occasionally, neither the VLP nor the VLS was found in either the long or the ring fingers. The vincula received blood supply from four transverse branches of the digital arteries. A volar avascular area of the profundus tendon was seen in the cleared cross-sections, and the cross-over zone of its intrinsic vessels was found to be at the midproximal phalanx.

Adolescent↗
PubMed1979

Hypoglycemia in mice administered with fusarenon-X.

Histological observation combined with determination of the serum glucose level and histochemical detection of liver glycogen was undertaken to examine the acute toxicity of fusarenon-X (FX) in mice. Mice intraperitoneally injected with a sublethal dose of the toxin showed rapidly developed hypoglycemia followed by depletion of liver glycogen. Mitotic inhibition was observed in many visceral organs and most markedly in the intestinal crypt cells, where the mitotic figures completely disappeared prior to the increase in number of the degenerated and nucrotic cells. No glycosuria was found. The disturbing effect of FX on the oral glucose tolerance test suggested the involvement of accelerated glycolysis and, more likely, of intestinal malabsorption.

Animals↗
PubMed1979

The mechanism of decrease in nucleolar RNA synthesis by protein synthesis inhibition.

When protein biosynthesis is inhibited by either cycloheximide of puromycine, the nucleolar RNA synthesis of Ehrlich ascites tumor cells decreases by approximately 70% within 1 h, while the removal of these protein synthesis inhibitors causes a rapid recovery of nucleolar RNA synthesis, largely within 1 h. A similar pattern of decrease and recovery of endogenous RNA polymerase activity in isolated nucleoli or in nuclei (in the presence of alpha-amanitin) may be demonstrated after addition and removal of these drugs. Analysis of the molecular species of RNA polymerase I on a phosphocellulose column indicates that only the IB form of the enzyme decreases in the nucleoli of drug-treated cells and recovers quickly after resumption of protein synthesis. The finding that the activity of the IB form enzyme remains unchanged in the whole nuclei indicates that during cessation of protein synthesis RNA polymerase IB is either released from the nucleoli into the extranucleolar compartment or becomes so loosely bound to the nucleoli that it is leached out from the nucleoli during their isolation. By using a system of assaying free, nucleolar-template bound and total RNA polymerase I activities, data supporting the above interpretation have been obtained. Namely, in isolated nuclei free enzyme activity increases with a concomitant decrease in bound enzyme activity during protein synthesis inhibition, while the total enzyme activity remains unchanged. In isolated nucleoli, both total and bound enzyme activities decreases on protein synthesis inhibition but recover quickly on its resumption. The putative bound enzyme, fractionated with the aid of actinomycin D, is exclusively IB form, whereas the unbound enzyme consists of both IA and IB forms as previously demonstrated (1). No conversion of IB form polymerase to IA form was noted on prolonged sonication in our system. The levels of ATP and GTP in the cell did not change appreciably either during cessation or resumption of protein synthesis in these cells. The data support the previous conclusion that some short-lived protein(s) is required to maintain the normal level of ribosomal RNA transcription (2) and further suggest that the protein is required to facilitate reinitiation of the transcription by RNA polymerase IB in the nucleolus.

Adenosine Triphosphate↗
PubMed1978

Primary reconstruction by modified cervical island skin flap following resection of oral and pharyngeal cancer.

Reconstruction of the intraoral defect following cancer surgery often causes formation of fistula, impairment of lingual movement, and prolonged hospitalization by secondary reconstruction. To reduce such complications, the modified cervical island skin flap method as a one-stage intraoral reconstruction was used in 18 patients. Lateral cervical island flap was used in 15 cases and the median flap in three. This method proved to be successful for 17 patients. One patient who received a preoperative full dose of irradiation developed a fistula. There were two types of healing of the skin flap. The postoperative external appearance and function of the tongue were commendable.

Carcinoma, Squamous Cell↗