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Biomedical subjects

T Yamano

Publications and source records attributed to T Yamano.

At least 235 records · Page 13Linked to original sources
PubMed1983

Studies on the phenotyping system of hyperlipoproteinemias. Evaluation of a new method by enzymic staining of lipids in serum lipoproteins separated by electrophoresis on agarose.

A new electrophoresis of lipoproteins was examined as a means of defining hyperlipoproteinemia phenotypes. The serum lipoproteins of 119 patients with hyperlipoproteinemia whose serum total cholesterol (TC) concentration was more than 250 mg and/or whose triglyceride (TG) concentration exceeded 180 mg per 100 ml were determined by using a method of electrophoretic separation of lipoproteins on agarose and enzymic staining of each lipid component separately. Based on the lipoprotein-lipid profile with the acid of various parameters for distinction, i.e., Type II A, LDL-C greater than or equal to 180 mg/dl: Type IV, VLDL-TG greater than or equal to 130 mg/dl: type II B, LDL-C greater than or equal to 130 mg/dl, 119 patients were classified into Fredrickson's phenotypes of hyperlipoproteinemia. The percentages of phenotypes with those hyperlipoproteinemias were: type II A, 31.1%; II B, 33.6; IV, 29.4%; and V, 5.9% respectively. But types I and III were not observed in this survey. The characteristics of the lipoprotein profiles of each phenotype were clearly identified, and they were: type II A, high peak LDL-C and decrease of HDL-C fraction; II B, high peak of LDL-C and VLDL-TG; IV, high peak of VLDL-TG; V, prominence of chylomicrons and high VLDL-TG peak. The serial observations of the lipoprotein-lipid profiles were very useful for detecting the progressive changes in lipoproteins which occurred during the course of diseases, particularly in cases of secondary hyperlipoproteinemia. In conclusion, the new lipoprotein-lipid profile based on the agarose electrophoresis-enzymic staining method not only offers great help in classification of hyperlipoproteinemia but has contributed to therapeutic management.

Adolescent↗
PubMed1983

Affinity of 18,19-dihydroxydeoxycorticosterone and 18-hydroxy-19-nor-deoxycorticosterone to aldosterone receptor and their mineralocorticoid activity.

Affinity of 18,19-dihydroxydeoxycorticosterone (18,19-diOH-DOC) and 18-hydroxy-19-nor-deoxycorticosterone (18-OH-19-nor-DOC) to aldosterone receptor and their mineralocorticoid activity were evaluated. 18,19-DiOH-DOC (1 X 10(-6) M) did not show appreciable binding to the receptor and its relative potency as a mineralocorticoid was estimated to be less than 1/8,000 of that of deoxycorticosterone (DOC). 18-OH-19-nor-DOC bound to the receptor with an affinity similar to that of 18-hydroxydeoxycorticosterone (18-OH-DOC) or spironolactone. Its sodium retaining activity was 0.04 times as great as that of DOC and similar to that of 18-OH-DOC.

18-Hydroxydesoxycorticosterone↗
PubMed1982

The pathogenesis of abnormal cytoarchitecture in the cerebral cortex and hippocampus of the mouse treated transplacentally with cytosine arabinoside.

Pregnant mice were treated with cytosine arabinoside on days 13.5 and 14.5 of pregnancy. Brains of the offspring were studied histologically. The matrix layer of the embryonic brains was extensively destroyed 12 h after the injection of cytosine arabinoside, but regenerated partially on day 17 of gestation. In the cerebral cortex of 1-, 3-, and 5-day-old treated mice, abnormal clusters of young neurons were found on the surface of the developing cerebral cortex. Some clusters still had a supply of immature neurons from the remnants of the regenerated matrix layer. After 20 days, the clusters became gradually indistinct, although some vestigial groups of neurons were observed even after 120 days. In the hippocampus of young mice, the pyramidal cells decreased in number and were disarranged. Heterotopic pyramidal cell masses were found in the stratum radiatum and in the molecular layer of the dentate gyrus. Apical dendrites of pyramidal cells exhibited abnormal arborization. It was demonstrated by 3H-thymidine autoradiography that young neurons in the abnormal clusters in the cerebral cortex were those produced in the matrix layer regenerated after the destructive change by cytosine arabinoside.

Abnormalities, Drug-Induced↗
PubMed1982

Gastroscopic biopsy of the stomach for the diagnosis of amyloidosis.

1. Amyloid deposition was investigated in the biopsied specimens obtained from the stomachs of suspected cases of amyloidosis. The subjects were seven cases of suggestive amyloidosis with clinical symptoms of muscle rigidity, masked face, macroglossia and B-J proteinuria. The stomach of an autopsied amyloidosis patient was also investigated. 2. Mucosal tissue was obtained from fundus, corpus and antrum of the stomach using gastrofiberscope, Olympus GFB2. And amyloid in the tissue was detected by H & E Congo red staining and polarization microscopy. Rectal biopsy was also done in the majority of the cases to compare with stomach biopsy. 3. Positive results were obtained with gastric biopsy in all seven cases and five of the 5 cases by rectal biopsy. Thus, gastric and rectal biopsy yielded the same results so far as detection of amyloid deposition was concerned. 4. Biopsy specimens from several sites of the stomach gave similar results in regard to the amyloid deposition. Tissue deposition of amyloid in the stomach wall showed a somewhat high incidence in the walls of intramucosal capillaries and in the walls of blood vessels of lamina muscularies mucosa. Gastroscopic biopsy of the stomach proved to be useful as a routine technique for the definite diagnosis of the disease.

Aged↗
PubMed1982

Hypertrophic and hypoactive smooth endoplasmic reticulum in hepatocytes uremic patients. A morphometric and biochemical study.

Morphometric analysis of the hepatic endoplasmic reticulum and assays of drug-metabolizing enzymes in microsomes prepared from needle biopsy specimens were performed with samples from uremic patients on chronic hemodialysis and normal controls. The smooth endoplasmic reticulum (SER) morphometrically increased in the uremic patients, whereas the cytochrome P-450 content and the activity of p-nitroanisole O-demethylase per mg microsomal protein decreased in the uremic patients. This condition of SER corresponds to that of the so-called hypoactive hypertrophic smooth endoplasmic reticulum, which could suggest lower activity of hepatic microsomal drug oxidation in uremic patients. On the other hand, the P-450 content and the activity of p-nitroanisole O-demethylase per g liver were not significantly different between the uremic and the normal subjects. This seems to indicate that the capacity of drug oxidation is retained in whole livers of uremic patients. However, since some patients in this study showed markedly low activity of p-nitroanisole O-demethylase per mg microsomal protein and per g liver, lipophilic drugs metabolized in the liver as well as hydrophilic ones eliminated by the kidney should be carefully administered to uremic patients.

Adult↗
PubMed1982

A spin trap study on anaerobic dehalogenation of halothane by a reconstituted liver microsomal cytochrome P-450 enzyme system.

In the presence of a spin trapping reagent, N-tert-butyl-alpha-phenylnitrone, anaerobic incubation of halothane (2-bromo-2-chloro-1,1,1-trifluoroethane) with a reconstituted cytochrome P-450 enzyme system of rabbit liver microsomes exhibited an electron spin resonance spectrum containing signals of a nitroxide radical, and all components of the reconstituted system were necessary to produce the nitroxide radical. Formation of 2-chloro-1,1,1-trifluoroethane, the product of anaerobic dehalogenation of halothane by the reconstituted system, was inhibited by N-tert-butyl-alpha-phenylnitrone. These results indicate that a radical intermediate of halothane is produced during the anaerobic dehalogenation reaction, and that the radical is trapped by N-tert-butyl-alpha-phenylnitrone to form a N-tert-butyl-alpha-phenylnitrone radical adduct.

Anaerobiosis↗
PubMed1982

A spin label study on human low density lipoprotein.

Selective labeling with N-(1-oxyl-2,2,6,6-tetramethyl-4-piperidinyl)-maleimide of human serum LDL has been performed. The spin-labeled LDL exhibited an ESR spectrum containing signals of a strongly immobilized component only. The signals were completely reversible between 4 degrees C and 37 degrees C and fairly stable at each temperature. The spin-labeled LDL which was prepared by the usual method exhibited an ESR spectrum containing signals of both strongly immobilized and weakly immobilized components (5, 6). The latter was unstable above 25 degrees C and changed irreversibly. The strongly binding site showed higher affinity for the nitroxide radical than the weakly binding site, and two kinds of the strongly binding site were demonstrated kinetically. The rate of binding of the nitroxide radical to the two kinds of strongly binding site were estimated to be 4.7 x 10(4) M-1 . day-1 and 0.16 x 10(4) M-1 . day-1 at pH 7.4 and 4 degrees C, respectively. Both the strongly immobilized and weakly immobilized radicals were reduced with ascorbate at the same rate. It was also shown on gel filtration of the SDS-treated LDL derivatives that the strongly immobilized component was on the apoprotein B moiety, whereas either noncovalent binding to LDL or binding to some small molecular species other than protein was suggested for the weakly immobilized component.

Binding Sites↗
PubMed1982

A resonance Raman study on the reaction intermediates of D-amino acid oxidase.

Resonance Raman (RR) spectra of two reaction intermediates of D-amino acid oxidase with substrate analogs were obtained. The reaction intermediates studied were (1) the one in the aerobic oxidative reaction of the enzyme with beta-cyano-D-alanine and (2) the other in the reverse reductive reaction of the enzyme with chloropyruvate and ammonium. Both intermediates are characterized with the charge transfer absorption bands in the long wavelength region extending beyond 600 nm. The RR spectra of the two intermediates excited at 488.0 or 514.5 nm are those of oxidized flavin, which is consistent with our previous assumption that oxidized flavin is involved in these reaction intermediates. Relatively simple RR spectra were obtained for these intermediates with excitation at 632.8 nm which is within the region of the charge transfer bands. The resonance enhancement for the Raman lines around 1585 and 1350 cm-1 for either of the intermediates with excitation in the region of the charge transfer bands suggests that the charge transfer interaction involves the N(5)-C(4a) region extending to the C(10a)-N(1)-C(2) region of the isoalloxazine nucleus. The Raman line at 1657 cm-1 for the intermediate with chloropyruvate and ammonium was assigned to C = N of an imino acid from the isotopic frequency shift upon 15N-substitution. The assignment substantiates our previous conclusion that the intermediate involves an imino acid, alpha-imino-beta-chloropropionate.

Aerobiosis↗
PubMed1982

Stimulatory effect of cytochrome b5 induced by p-nitroanisole and diisopropyl 1,3-dithiol-2-ylidenemalonate on rat liver microsomal drug hydroxylations.

The relationship between the changes in the amount of the components of the liver microsomal electron transport systems and drug hydroxylase activities on administration of p-nitroanisole was investigated. The content of cytochrome P-450 in the p-nitroanisole-treated rats was not significantly different from that in the controls during the treatment. The cytochrome b5 content increased 2.2-fold over that of the controls after 14 days of treatment. Demethylation activities per mg microsomal protein of p-nitroanisole, aminopyrine, and benzphetamine were enhanced 2.7-, 2.4-, and 2.8-fold, respectively, but aniline hydroxylase activity was not enhanced. Similar results were obtained with microsomes from diisopropyl 1,3-dithiol-2-ylidenemalonate (NKK-105)-treated rats. The time-course study of changes in the amount of the components of drug hydroxylase systems suggested that the increase in cytochrome b5 content enhanced the demethylation activities. In the reconstituted system containing cytochrome P-450 partially purified from p-nitroanisole- or NKK-105-treated rats, cytochrome b5 was required for the maximal activities of the demethylation reactions, but did not participate in aniline hydroxylation. These findings showed good correlation between the change of cytochrome b5 content and the demethylation activities and suggested that the increase in cytochrome b5 content might enhance the demethylation activity by stimulating supply of a second electron to cytochrome P-450.

Animals↗
PubMed1982

Arginyl residues of adrenodoxin reductase as the anion recognition site for 2'-phosphate group of NADP+1.

Adrenodoxin reductase from bovine adrenocortex was inactivated by arginine specific reagents, p-hydroxyphenylglyoxal, phenylglyoxal, 2,3-butanedione, and 1,2-cyclohexanedione. Inactivation of the enzyme caused by p-hydroxyphenylglyoxal obeyed pseudo-first-order kinetics and resulted in complete elimination of NADPH-ferricyanide reductase activity. The rate of inactivation increased with pH from 6.5 to 9.5. Ten out of 30-33 arginyl residues of the enzyme were modified, but residues essential to its enzymatic activity were less than 5. NADP+ strongly protected against inactivation by p-hydroxyphenylglyoxal, whereas NAD+ could afford only partial, weak protection. Furthermore, 2'-AMP and 2',5'-ADP afforded considerable protection but 5'-AMP did not. These data suggest that adrenodoxin reductase has essential arginyl residues which are crucial to the enzymatic activity as the recognition site for the negatively charged 2'-phosphate group of NADP+.

Animals↗
PubMed1982

Thermodynamic characterization of hog kidney D-amino acid oxidase apoenzyme in concentrated guanidine hydrochloride solution. Preferential interaction with the solvent components and the molecular weight of the monomeric unit.

This paper describes the physical characterization of the monomeric unit of hog kidney D-amino acid oxidase apoenzyme in 6 M guanidine hydrochloride (GuHCl) solution by means of differential refractometry, densimetry, light scattering, equilibrium sedimentation, and high-speed gel filtration chromatography. In 6 M GuHCl solution, the oxidase interacts preferentially with GuHCl: the values of the preferential interaction parameter are 0.11 +/- 0.03 (S.D.) g/g of protein by densimetry and 0.14 +/- 0.04 g/g of protein by refractometry. The volume change, delta V, of the oxidase on transfer from the native to the denatured state is -350 ml/mol. The molecular weight of the monomeric apoenzyme is 39,600 +/- 1,700 by light scattering and 38,000 +/- 1,200 by high-speed equilibrium sedimentation. The values of the molecular weight estimated by the empirical methods, i.e., sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis and high-speed gel filtration chromatography in 6 M GuHCl, agree well with those obtained by the thermodynamic methods mentioned above. These results confirm definitely that the complex of the apoenzyme with SDS normally behaves in the same manner as those of standard proteins in SDS-gel electrophoresis. This is also supported in this study by the analysis of the electrophoretic data at several gel concentrations by Ferguson plots. The molecular weight of quasi-D-amino acid oxidase apoenzyme was also examined by the empirical methods.

Animals↗