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Biomedical subjects

T Tezuka

Publications and source records attributed to T Tezuka.

At least 181 records · Page 10Linked to original sources
PubMed1983

[A simple method for radioimmunoassay of total estrogen in urine].

A simple and rapid radioimmunoassay (RIA) without extraction or purification was developed for Total Estrogen (conjugated and unconjugated estrogen) in urine from normal men and nonpregnant women. Antiserum used to RIA was produced by immunizing rabbits with estriol-16 alpha-glucuronide (E3-16-G)-BSA conjugates. Antiserum to E3-16-G.BSA significantly cross-reacted with E1 (100%), E2 (100%), E3 (100%), E3-16-G (100%), AND E3-17-G (100%) and did not react with other conjugated estrogen in urine. Urinary estrogen glucuronides and sulfates were gently hydrolyzed by beta-glucuronidase from Helix pomatia juice for 2hr (48 degrees C) without inhibition, and hydrolysis urine was directly applied to RIA. The results obtained from this direct method correlated well with the chromatographic purificating method, the extracting method and the Brawn-Kambegawa method (colorimetric method). This direct method is very useful for clinical application.

Estriol↗
PubMed1983

Liposomal membranes. XIV. Fusion of liposomal membranes induced by polyisoprenoids as monitored by fluorescence quenching method.

Fusion of the single-walled liposomes of egg phosphatidylcholine as induced by the polyisoprenoids such as solanesol, trans-ethyl decaprenoate (EDP), coenzyme Q10, and dolichol has been investigated adopting the fluorescence quenching method. Relative efficiency of the polyisoprenoids employed on the induced fusion of liposomes was a sequence of solanesol less than or equal to EDP much less than CoQ10, dolichol, which was consistent with the result previously obtained by the dye-release method.

Cell Fusion↗
PubMed1983

Isolation and Characterization of Inner Membrane-Associated and Matrix NAD-Specific Isocitrate Dehydrogenase in Potato Mitochondria.

The isotherm for isocitrate oxidation by potato (Solanum tuberosum L. var. Russet Burbank) mitochondria in the presence of exogenous NAD is characterized by a hyperbolic phase at isocitrate concentrations below 3 millimolar, and a sigmoid, or positively cooperative phase from approximately 3 to 30 millimolar. The two forms of isocitrate dehydrogenase were separated and characterized following the sonication of mitochondria in 15% glycerol in the absence of buffer, followed by fractionation in a density step gradient to yield inner membrane and matrix components. The membrane-associated isocitrate dehydrogenase was found to have a Hill, or cooperativity, number of 1, while the Hill number of the matrix enzyme was 2.5. Upon digitonin extraction the cooperativity number of the membrane enzyme rose to 3.5. The isocitrate K(m) for the membrane enzyme was calculated to be approximately 5.9 x 10(-4) molar, while the S(0.5) for the matrix was 6.9 x 10(-4) molar. The NAD K(m) for both enzymes was 150 micromolar. Whereas the membrane enzyme proved indifferent to adenine nucleotides, the matrix enzyme was arguably inhibited by AMP and ADP, and inhibited some 25% by 5 millimolar ATP. Both enzymes were negatively responsive to the mole fraction of NADH, the membrane enzyme being 50% inhibited at a mole fraction of 0.26, and the matrix enzyme by a mole fraction of 0.32. The suggestion is offered that the enzymes in question constitute two forms of a single enzyme, one peripherally associated with the inner membrane, and one soluble in the matrix. It is proposed that a degree of regulation may be achieved by the apportionment of the enzyme between the bound and free forms.

Journal Article↗
PubMed1983

Electron-microscopic changes in xerosis senilis epidermis. Its abnormal membrane-coating granule formation.

Skin specimens of patients with xerosis senilis were examined electron microscopically. The changes were as follows: (1) The electron density of the stratum corneum was uniformly low and no keratin pattern was observed in the lowermost cells of the stratum corneum. (2) The number of keratohyalin granules was decreased but their electron density was normal. (3) There were no lamellate membrane-coating granules formed in the cells of the stratum granulosum and there were many small vesicles which were similar in size and shape to membrane-coating granules, but lacked a lamellate internal structure. This abnormal vesicle formation occurred in the epidermis of the same xerosis senilis patients both in winter and summer. This observation indicates that the change in the formation of membrane-coating granules could be an age-dependent disorder of the differentiation of keratinocytes. (4) Being accompanied by an age-related reduction in lipid production, the deficient formation of membrane-coating granules leads to the disappearance of the lipid film which surrounds the stratum corneum cells. This and the reduction in the surface lipid originating in the sebaceous glands could result in an increase in transepidermal water loss leading to the asteatotic scaly stratum corneum seen in the skin of patients with xerosis senilis in winter.

Aged↗
PubMed1983

Histidine-rich and cystine-rich keratohyalin granules in hamster cheek pouch epidermis. 1. Histochemical examination with a fluorescent thiol reagent (DACM).

Hamster cheek pouch epidermis was examined with a thiol-specific fluorescent reagent [7-(N-dimethylamino-4-methyl-3-coumarinyl) maleimide (DACM)], with the Pauly reagent and by electron microscopy. There were many keratohyalin granules in the cells of the stratum granulosum where they were positively stained with the Pauly reagent, and were fluorescent as a whole, rather than partially, with DACM with or without reduction of disulfide bonds. These data indicate that the whole of a keratohyalin granule was rich in both histidine and cystine. Besides keratohyalin granules, the cellular envelope of the lower half of the stratum corneum showed fluorescence before reduction of disulfide bonds and following reduction of disulfide bonds, the cellular envelope of all stratum corneum cells showed fluorescence. Electron microscopically, keratohyalin granules in hamster cheek pouch epidermis were electron-dense and had a homogeneous structure which was identical to small keratohyalin granules in newborn rat epidermis. Structures corresponding to the single granule of Jessen or to dense homogeneous deposits were not seen. When the specimen was fixed in glutaraldehyde alone, keratohyalin granules consisted of electron-dense and electron-translucent parts. However, the profile was different from that of composite granules seen in both rat tongue epithelium and newborn rat epidermis. Several membrane coating granules were seen in stratum granulosum cells, and marginal band formation also occurred.

Animals↗
PubMed1982

Dyskeratotic process of hyperkeratosis lenticularis perstans (Flegel). The abnormal formation of cystine-rich protein.

The dyskeratotic changes in the lesions of hyperkeratosis lenticularis perstans were examined electron microscopically and histochemically. Under electron microscopy, the formation of keratohyalin granules was reduced and there was a lack of lamellar granule formation. In addition, the catabolic processes were disturbed, and ribosomal and mitochondrial structures remained, and lipid crystal-like structures were seen in the stratum corneum. The structure of the desmosomes of the stratum corneum was identical to that seen in the stratum spinosum. Staining with thiol-specific, fluorescent reagent, N-(7-dimethylamino-4-methyl-coumarinyl) maleimide (DACM) demonstrated strong fluorescence in the cytoplasm of the stratum corneum and granulosum without reduction by 2-mercaptoethanol. With reduction, moderate fluorescence was only seen at the periphery of the stratum corneum cells. These results indicate that there is a cystine-rich protein in the stratum corneum cells.

Cystine↗
PubMed1982

Viscometric analysis of effects of cytochalasins on in vitro polymerization and depolymerization of microtubules.

Nineteen cytochalasins including 6 natural cytochalasins, 2 natural aspochalasins, 7 natural chaetoglobosins and 4 their acetates were investigated by viscometry to examine their effects on in vitro polymerization and depolymerization of microtubules. Cytochalasin A was proved as an only active cytochalasin, confirming the studies of Himes et al., and others showed very weak or no noticeable effects. This results indicate that a wide range of effects of cytochalasins are not related to interactions with microtubules.

Animals↗
PubMed1980

Thrombin inhibitors. 2. Amide derivatives of N alpha-substituted L-arginine.

A series of N alpha-(arylsulfonyl)-L-arginine amide derivatives with substituted or unsubstituted naphthalene and heterocyclic compounds as the N alpha-substituent was prepared and tested as inhibitors of the clotting activity of thrombin. N-n-Butyl and N-n-butyl-N-methyl derivatives of N alpha-dansyl-L-arginine amide were the most inhibitory of N-alkyl and N,N-dialkyl derivatives of N alpha-dansyl-L-arginine amide. Their inhibitory effect was as potent as that of N alpha-dansyl-L-arginine-n-butyl ester with an I50 of 2 X 10(-6) M. N alpha-Substituted naphtalenesulfonyl-L-arginine amide derivatives of 4-methyl- and 4-ethylpiperidine also showed a potent inhibition with an I50 of 10(-7) to 10(-6) M. The most potent inhibitior in this study was 1-[N alpha-(4,6-dimethoxynaphthalene-2-sulfonyl)-arginyl]-4-methylpiperidine, with an I50 of 7.5 X 10(-8) M. Arginine amide derivatives of 4-methyl- or 4-ethylpiperidine with tetralin or an oxygen-containing heterocyclic compound as a N alpha-substituent showed an inhibition with an I50 less than 10(-5) M. N-Monosubstituted derivatives of N alpha-dansyl-L-arginine amide were not hydrolyzed at all by thrombin and were hydrolyzed very slowly by trypsin, and N,N-disubstituted derivatives were not hydrolyzed at all by both enzymes.

Amides↗