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Biomedical subjects

T Oka

Publications and source records attributed to T Oka.

At least 1,297 records · Page 72Linked to original sources
PubMed1982

Transplantation of the reversed dermis from skin leading to repair of the buccal mucosal epithelium.

Skin grafting or mucosal grafting has been widely applied as the established method to compensate mucosal defects. However, in the grafted skin the epidermis never transformed into the mucosal epithelium; the original nature of the transplant was maintained as skin. The available donor of mucosa is also strictly limited. Therefore, an improvement in method has been much needed in the field of oral surgery. We tried to transplant the dermis freed completely from the epidermis instead of the full-thickness skin, and succeeded in compensation of the mucosal defect. The defects of the buccal mucosa in 30 dogs were repaired, one side with reversed dermis graft (RDG) in which the dermis was turned inside out and sutured onto the bed. On the other side, the ordinary free full-thickness skin graft (FTSG) was carried out as a control. Comparative clinical and histological observations were conducted to analyze the healing processes. In RDG the graft was covered by the surrounding mucosal epithelium to form the mucosal tissue, while the implanted tissue inhibited the wound constricture. Histological examination revealed that the epithelial elements underwent degeneration, presumably through being embedded by the grafting of the dermis inside out. The epithelium covering the dermis graft seems to be nothing but normal oral mucosal epithelium.

Animals↗
PubMed1982

The regulatory function of spermidine in hormonal control of the development of mouse mammary gland in culture.

The interplay of insulin, glucocorticoid, and prolactin induces differentiation of mouse mammary gland in culture. Earlier studies indicated that spermidine plays a key role in hormonal control of mammary development by mediating some of the lactogenic actions of glucocorticoid. In this study we examined the effect of progesterone, an inhibitor of lactogenesis, on milk protein synthesis and spermidine accumulation. The maximal degree of inhibition, which was attained at 300 nM, was about 40% for casein synthesis, 90% for alpha-lactalbumin synthesis, and 70% for spermidine accumulation. The increase in the activity of S-adenosyl-L-methionine decarboxylase and spermidine synthetase, two key enzymes in polyamine biosynthesis, was inhibited by 55 and 65%, respectively, by progesterone. The extent of progesterone inhibition of milk protein synthesis was greatest in cultured tissue from virgin mice, which contained a low level of spermidine, whereas mammary explants from lactating mice, which contained a high level of spermidine, were insensitive to progesterone. The inhibitory effect of progesterone can be partially antagonized by cortisol, which causes an enhancement of spermidine accumulation. These results suggest that the synthesis and accumulation of spermidine serve as targets for the inhibitory action of progesterone on lactogenesis.

Adenosylmethionine Decarboxylase↗
PubMed1982

Identification and characterization of endogenous inhibitors of polyamine-responsive protein kinase activity.

Polyamine-responsive protein kinase activity was inhibited by two heat stable inhibitors which were purified from Morris hepatoma 3924A. They were of low molecular weight (inhibitor I-1,600 to 2,000, inhibitor II-600 to 800 daltons). The inhibitors, when purified, passed through a DEAE-cellulose column; however, the crude complex of inhibitors and protein kinase activity bound to the DEAE-cellulose column. This suggests that the inhibitors are bound to the polyamine-responsive protein kinase in vivo. Both inhibitors completely inhibited the polyamine stimulated activity, but did not affect the basal enzymatic activity. They were not affected by treatment at 90 degrees for 2 min. These results demonstrate the presence of two new protein kinase inhibitors in mammalian cells.

Animals↗
PubMed1982

[Effect of NK-421 (Bestatin) and Ge-132 on the cytotoxicity of spleen cells obtained from the tumor-bearing mice].

The effect of NK-421(Bestatin) and Ge-132 (an organic germanium compound) on the ADCC and natural killing (NK) activities of the spleen cells of MH-134 tumor-bearing mice were studied. In the tumor-bearing mice, the ADCC activity was enhanced, and NK activity was reduced in accordance with the progress of the tumor. By oral administration of Bestatin at doses of 5, 10 and 50 mg/kg, ADCC activity was potentiated, and at a dose of 10 mg/kg, NK activity was significantly increased. Intraperitoneal administration of Ge-132 at 50 mg/kg potentiated the ADCC activity of tumor-bearing mice. A higher activity was observed in the plastic dish adherent fraction. Ge-132 also potentiated the reduced NK activity of tumor-bearing mice to higher level than normal mice. The elevated activities of ADCC and NK following Bestatin and Ge-132 administration were decreased with anti-Thy-1 antibody and complement; however, the percent reduction was lower compared to that of the control cancer animals. This result indicates that Bestatin and Ge-132 may act on non-T cells and augment ADCC and NK activities.

Adjuvants, Immunologic↗
PubMed1982

[Experimental and clinical studies of bestatin as an immunomodulator].

The experimental and clinical effects of bestatin were examined and the results obtained were as follows. Bestatin which is an immunomodulator discovered by Umezawa did not increase the bone marrow stem cells examined by the method of the spleen colony assay in the 60Co irradiated mouse. However, it prolonged the survival time slightly when it was administered 10-25mg/kg intraperitoneally. Clinically, bestatin was administered to the patients with gastrointestinal cancer. It did not influence on the PHA-induced lymphocyte blastformation rate, but it increased the peripheral lymphocyte count and PPD skin reaction in the cases of curative resection and increased the peripheral lymphocyte counts in the cases of nonresection after 1 month of the operation.

Adjuvants, Immunologic↗
PubMed1981

The importance of local hemostatic procedures in dental extractions and oral mucosal bleeding of hemophiliac patients.

Deficient coagulation factor replacement therapy is often indispensable for dental extractions and oral mucosal bleeding in hemophiliac patients. High concentrates are often infused in large amounts of volume, until complete hemostasis is achieved. Considering the various side effects of replacement therapy the volume infused should be reduced to a minimum. Several aspects associated with replacement therapy for the control of oral bleeding are studied. Our conclusion is that local hemostatic procedures are even more important than replacement therapy. The use of surgical packs and band retainers proved to be of benefit in this study.

Adolescent↗
PubMed1981

Peptide bond synthesis catalyzed by subtilisin, papain, and pepsin.

The peptide bond syntheses catalyzed by subtilisin BPN', papain [EC 3.4.22.2], and pepsin [EC 3.4.23.1] were studied comparatively at the optimum pH of the enzymes with the coupling system Cbz-(AA)n-OH + Leu-X leads to Cbz-(AA)n-Leu-X, in which AA = various amino acid residues, n = 1-3 and X = -NH2, -OEt, -OBut, -ODPM (diphenyl methyl ester) or -NH. The coupling with these enzymes differed depending upon the nature of (AA)n and X. For subtilisin-catalyzed coupling, the molecular size of the carboxyl component was most important. Thus, Cbz-Gly-Pro-Leu-OH was useful for synthesis in the presence of an equimolar concentration of Leu-NH. Either Ala-NH2 or Leu-NH2 was also useful as an amine component when present at a concentration several times that of the carboxyl component. Papain catalyzed the coupling between Cbz-AA-OH (AA = glycine, L-alanine, L-valine, L-glutamic acid, or L-phenylalanine) and Leu-X (X = -OBut and -ODPM). The coupling of Cbz-Gly-Phe-OH and Leu-X catalyzed by pepsin was markedly affected, depending upon the nature of X in the following order: -NH greater than -OBut greater than -NH2, -OEt. Leu-NH2, however, was quite efficient when its molar concentration was raised to twenty times that of the carboxyl component.

Hydrogen-Ion Concentration↗
PubMed1981

A new device for free skin grafting in rats.

We have employed this device in more than 200 grafting operations with complete success. Its advantage is to avoid the variation of fixing pressure on the grafts that greatly interferes with the experimental results. In addition, this method allows us to inspect the graft during the first week without having to remove the protector each time, which helped us greatly. We have presented a new device for skin grafting in rats that allows us to obtain temporary stabilization and protection of a skin graft. In addition, it allows us to inspect the graft without having to remove the protector.

Animals↗
PubMed1981

Cell wall composition of Micromonospora olivoasterospora, Micromonospora sagamiensis, and related organisms.

Cell walls of 19 Micromonospora species were analyzed for their components. All the cell walls had xylose and arabinose, but the presence of glucose, galactose, mannose, or rhamnose depended on the strain. Amino acids present in the walls consisted of glycine, glutamic acid, diaminopimelic acid, and alanine, in a molar ratio of approximately 1:1:1:0.6--0.8. 3-Hydroxydiaminopimelic acid, together with meso-diaminopimelic acid, was found in many species and was isolated from Micromonospora olivoasterospora to compare the color constant in an amino acid analyzer with that of meso-diaminopimelic acid. The cell walls of Micromonospora sagamiensis and M. olivoasterospora contained only D-alanine and not L-alanine. All species tested except Micromonospora globosa contained glycolate in an almost equimolar ratio to diaminopimelic acid in their cell walls. Among 45 strains of 12 genera examined, Actinoplanes, Ampullariella, Amorphosporangium, and Dactylosporangium species had a significant amount of glycolate in the whole cells. Based on these results, the primary structure of the peptidoglycan of Micromonospora is discussed.

Actinomycetales↗
PubMed1981

Immunoreactivity and biologic activity of semisynthetic [LeuB-30]-insulin: potential value in the treatment of insulin antibody-mediated insulin resistance.

Insulin analogues with different amino acids, including threonine, alanine, L-leucine, D-leucine, L-leucine amide, phenylalanine, tri-alanine, or desalanine, at the B-30 position were semisynthesized from pork insulin by the new enzymatic method. The order of ability of the insulin analogues to bind to anti-insulin sera was [AlaB-30] greater than desalanine greater than [ThrB-30] greater than [Ala-Ala-AlaB-30] greater than [D-LeuB-30], [Leu-NH2B-30],[PheB-30] greater than desoctapeptide greater than or equal to [LeuB-30]. The ability of insulin analogues with different amino acids at B-30 to bind to receptors, as well as their biologic potency tested with glucose uptake in isolated rat adipocytes, was comparable among the analogues. These results suggest that [LeuB-30]-insulin demonstrated the least immunoreactivity and has full activity in receptor binding and biologic effect, and that it may be useful for treatment of anti-insulin antibody-mediated insulin resistance.

Adipose Tissue↗