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T Suga

Publications and source records attributed to T Suga.

At least 199 records · Page 11Linked to original sources
PubMed1989

Determination of 17-oxosteroid sulphates in serum by ion-pair extraction, prelabelling with dansylhydrazine and high-performance liquid chromatography with fluorescence detection.

A new high-performance liquid chromatographic (HPLC) method with fluorescence detection is described for the direct determination of four serum 17-oxosteroid sulphates. Each serum sample was deproteinated with methanol, the methanol was evaporated and 17-oxosteroid sulphates in the residue were extracted with benzene as ion pairs in the presence of tetrapentylammonium ion. The ion pairs were labelled with dansylhydrazine and the hydrazones were separated by HPLC on a Capcell-Pak C8 (silicone polymer-coated silica gel modified with octyl groups) reversed-phase column using methanol-0.5% (w/v) sodium acetate-50% (v/v) acetic acid (57:42:1, v/v/v) as the mobile phase. The eluent was monitored with a fluorometric detector at an excitation wavelength of 330 nm and an emission wavelength of 540 nm.

17-Ketosteroids↗
PubMed1989

Compartmentation of dicarboxylic acid beta-oxidation in rat liver: importance of peroxisomes in the metabolism of dicarboxylic acids.

Peroxisomal and mitochondrial beta-oxidation of dicarboxylic acids (DCAs) were investigated and compared. When isolated hepatocytes were incubated with DCAs of various chain lengths, H2O2 was derived from peroxisomal beta-oxidation, the rates of its generation being comparable to those seen with monocarboxylic acids (MCAs), whereas the rates of ketone body production, a measure of mitochondrial beta-oxidation, were much lower than those with MCAs. Peroxisomal beta-oxidation measured by cyanide-insensitive NAD reduction exhibited similar chain-length specificities for both dicarboxylyl-CoAs (DC-CoAs) and monocarboxylyl-CoAs (MC-CoAs), except that the activities for DC-CoAs with 10-16 carbon atoms were about half of those of the corresponding MC-CoAs. In contrast, mitochondrial beta-oxidation measured by antimycin A-sensitive O2 consumption had no activity for DCAs. In the study with purified enzymes, the reactivities of mitochondrial carnitine palmitoyltransferase and acyl-CoA dehydrogenase for DC-CoAs were much lower than those for MC-CoAs, while the reactivity of peroxisomal acyl-CoA oxidase for DC-CoAs was comparable to that for the corresponding MC-CoAs. Accordingly, the properties of carnitine palmitoyltransferase and acyl-CoA dehydrogenase must be the rate-limiting factors for mitochondrial beta-oxidation, with the result that DCAs might hardly be oxidized in mitochondria. Comparative study of beta-oxidation capacities of peroxisomes and mitochondria in the liver showed that DC12-CoA was hardly subjected to mitochondrial beta-oxidation, and that the beta-oxidation of DCAs in rat liver, therefore, must be carried out exclusively in peroxisomes.

Acyl-CoA Dehydrogenases↗
PubMed1989

Species differences in the effects of bezafibrate, a hypolipidemic agent, on hepatic peroxisome-associated enzymes.

The effects of bezafibrate on hepatic peroxisome-associated enzymes of rats, mice, guinea pigs, hamsters, rabbits, dogs and monkeys were examined. Dogs and monkeys were given bezafibrate orally at 30 mg/kg body wt daily for 2 weeks and at 125 mg/kg body wt daily for 13 weeks, respectively, and other species at 100 mg/kg daily for 2 weeks. In male rats, marked changes were observed in the activities of catalase (1.73-fold), D-amino acid oxidase (DAAO; 0.56-fold), fatty acyl-CoA oxidizing system (FAOS; 12.9-fold) and carnitine acetyltransferase (CAT; 35.8-fold); in female rats, the changes were less than in the males. In mice, there were no apparent sex differences in the responses of hepatic peroxisomal enzymes to bezafibrate and the increases in the activities of catalase, FAOS and CAT were 1.76-, 3.75- and 7.94-fold respectively. In guinea pigs, only slight increases in the activities of FAOS (3.00-fold) and CAT (2.83-fold) were observed. In hamsters, the increases in catalase, FAOS and CAT activities, were 1.23-, 2.19- and 2.77-fold respectively. Although rabbits and dogs showed slight increases in CAT activity, no significant response to the drug was observed in monkeys. Hepatomegaly and the increase of hepatic content of peroxisome proliferation-associated polypeptide (PPA-80), which has been recognized as a peroxisomal bifunctional protein in the fatty acid beta-oxidation pathway, were observed only in rats and mice. These results show that there were marked species differences in the effects of bezafibrate on hepatic peroxisomes, and that bezafibrate induced hepatic peroxisome proliferation in rodents, especially rats and mice.

Animals↗
PubMed1989

Turnover of fatty acyl-CoA oxidase in the liver of rats fed on a partially hydrogenated marine oil.

The change in turnover of fatty acyl-CoA oxidase (FAO), the rate-limiting enzyme of the peroxisomal beta-oxidation system, was investigated in rats fed a 30% (w/w) partially hydrogenated marine oil (PHMO) diet. The FAO activity increased five-fold after two weeks of PHMO feeding, and decreased after withdrawal of the diet. Based on in vivo experiments using L-[4,5-3H]leucine and an immunoprecipitation technique, the increase in the activity of FAO could be accounted for by a 1.6-fold higher rate of FAO synthesis and a 3.4-fold slower rate of FAO degradation as compared to controls. In the same PHMO-fed rats, the rates of synthesis and degradation of carnitine palmitoyltransferase were 1.8-fold higher and 2.0-fold slower, respectively, as compared to controls. The results indicate that the observed increase in the activity of the enzymes of peroxisomal beta-oxidation is mainly due to a reduced rate of FAO degradation in the liver of rats fed the PHMO diet.

Acyl-CoA Oxidase↗
PubMed1989

Existence of acetyl-CoA-dependent chain elongation system in hepatic peroxisomes of rat: effects of clofibrate and di-(2-ethylhexyl)phthalate on the activity.

The acetyl-CoA-dependent elongation of medium-chain acyl-CoA in the presence of pyridine nucleotide was studied in rat liver. The activity was increased by the administration of peroxisome proliferators, clofibrate and di-(2-ethylhexyl)phthalate, and the change was more remarkable in peroxisomes than in mitochondria. Addition of 0.01% Triton X-100 to the incubation mixture caused an increase in the mitochondrial activity, whereas the peroxisomal activity did not increase significantly. The pH optimum for the peroxisomal activity was in the range of pH 6.5-7.0 and that for the mitochondrial activity was pH 7.5-8.0. The specificities of primer chain length in both organelles were almost the same, and octanoyl-CoA was the preferred substrate. Peroxisomal activity was completely inhibited by the addition of 1 mM N-ethylmaleimide or 1 mM p-hydroxymercuribenzoic acid, while the activity did not change on the addition of 1 mM KCN or an antibody to acyl-CoA oxidase, the first enzyme of the peroxisomal beta-oxidation system. The activity of enoyl-CoA reductase, which catalyzes the last step of the elongation system, was also detected in peroxisomes, although the main activity was localized in microsomes. When the liver peroxisomal fraction of clofibrate-treated rats was incubated with a mixture of octanoyl-CoA, acetyl-CoA, NADH, NADPH, and Triton X-100 in a buffer system, dodecanoyl-CoA was detected as the main product by radio-gas chromatography. On the other hand, the elongation activity was decreased greatly by the addition of NAD+ into the mixture. These results indicate that (i) peroxisomes have activity to elongate medium chain acyl-CoA; (ii) the peroxisomal elongation system may consist of the reverse reaction of the beta-oxidation system except for the last step, which is catalyzed by enoyl-CoA reductase; and (iii) the peroxisomal elongation system is less active than the beta-oxidation system under physiological conditions.

Acetyl Coenzyme A↗
PubMed1989

Identity of acyl-CoA oxidase with glutaryl-CoA oxidase.

Rats fed on clofibrate- and DEHP-containing diets showed virtually proportional increases in hepatic acyl-CoA oxidase and glutaryl-CoA oxidase activities. The solubilization profiles of the two activities from the light mitochondrial fraction of the liver homogenate of DEHP-treated rats were the same, and the glutaryl-CoA oxidase/acyl-CoA oxidase activity ratio remained constant through the purification. The final preparation obtained was a single protein based on the result of polyacrylamide gel electrophoresis. The evidence indicates that the two activities are associated with the same protein.

Acyl-CoA Oxidase↗
PubMed1989

Subpopulations of T alpha cells in patients with IgA nephropathy: correlation between T alpha 4 cells and in vitro IgA production.

T cells play important roles in the regulation of the immune system and are divided into subpopulations by various kinds of markers on the membrane surface. T cells with Fc-receptors for IgA are termed T alpha cells, and the properties of this cell population have been revealed in recent years. T alpha cells are increased in patients with IgA nephropathy and possess IgA specific helper activity. T alpha cells consist of two subpopulations, T alpha cells with OKT4 antigen (T alpha 4 cells) and with OKT8 antigen (T alpha 8 cells). To investigate the immunological aberrations in patients with IgA nephropathy, we detected immunoglobulin produced by peripheral blood lymphocytes and enumerated the numbers of T alpha cells (including both T alpha 4 and T alpha 8 cells). The numbers of T alpha 4 cells (but not T alpha 8 cells) and in vitro IgA production were increased in patients with IgA nephropathy (IgA nephropathy, mean 1.9%. Control, mean 0.8%. P = 0.0075). In addition, the numbers of T alpha 4 cells and the amount of IgA in the supernatant of lymphocyte cultures were positively correlated in these patients (P = 0.025. r = 0.3836). From the results in the present study, it was suggested that T alpha 4 cells might be related to immunological aberrations, such as an increase in IgA seen in patients with IgA nephropathy.

Adult↗
PubMed1989

Comparative pharmacokinetics of clarithromycin (TE-031), a new macrolide antibiotic, and erythromycin in rats.

Clarithromycin (TE-031) is a newly synthesized macrolide with high stability in acidic conditions. In the present study, the pharmacokinetics of [N-methyl-14C]clarithromycin were compared with those of [N-methyl-14C]erythromycin in rats by radioassay and bioassay. Both radioactivity and bioactivity of [14C]clarithromycin in plasma and tissues were found to be significantly higher than those of [14C]erythromycin at the same oral dose of 20 mg/kg (body weight). Among the tissues, the peak level of [14C]clarithromycin in the lung was especially high. Levels of radioactivity and bioactivity amounted to 15 and 73 times the corresponding levels of [14C]erythromycin. In the urine, bioactivity recovered after administration of [14C]clarithromycin was sevenfold higher than that for [14C]erythromycin. This accounted for about 60 and 20% of the total radioactivity in the urine for [14C]clarithromycin and [14C]erythromycin, respectively. An examination of metabolites in the urine for [14C]clarithromycin revealed appreciable amounts of bioactive unchanged clarithromycin. These results indicate that clarithromycin has pharmacokinetic properties superior to those of erythromycin. The desirable properties of clarithromycin include high levels in plasma resulting from its high stability in gastric acid; a high tissue affinity, especially to the lung; and favorable urinary excretion.

Administration, Oral↗
PubMed1989

Acute hydrothorax in continuous ambulatory peritoneal dialysis--a collaborative study of 161 centers.

Follow-up studies on 3,195 patients from 161 centers in Japan undergoing continuous ambulatory peritoneal dialysis (CAPD) were performed for 1-104 months to clarify the incidence as well as the clinical features of acute hydrothorax. In these studies, 50 patients (1.6%) developed this complication. Twenty-seven (54%) were men, and 23 (46%) were women, ranging in age from 6 to 79 (average 49) years. The interval between onset of CAPD and hydrothorax ranged from 1 day to 8 years. Four had left-sided, and 2 had bilateral hydrothorax, but the majority (88%) were right-sided. Dyspnea was experienced by 37 of these 50 patients, but the remaining 13 (26%) patients were asymptomatic. Hydrothorax was fully resolved in 27 of them following a brief interruption of CAPD or the combined use of small exchange volumes in a semi-sitting position and pleurodesis with tetracycline or other agents. The remaining 23 patients (46%) were switched to hemodialysis permanently. Despite recurrence, 1 patient continued successfully on CAPD. It was concluded that acute hydrothorax is one important possible complication, although the risk may be low. Constant surveillance is necessary to detect pleural effusions in patients during CAPD.

Acute Disease↗
PubMed1989

Effects of quaternary ammonium compounds on the degradation of lipids in lysosomes.

We have examined effects of quaternary ammonium compounds on the in vitro degradation of endogenous lipids in isolated lysosomes. The degree of lipid degradation was assessed by determining hydrolysis products of labeled lipid. Lipolysis was inhibited by quaternary ammonium compounds. The degrees of inhibition were as follows: ethidium bromide greater than N-methylatropinium bromide (NMA) greater than tubocurarine. The inhibition of lipolysis by these quaternary ammonium compounds is not necessarily correlated with the differences in their polarities, molecular weight or structures. The degradation of three phospholipid classes was inhibited by NMA with phosphatidylcholine the most vulnerable. The effect of NMA on the hydrolysis of [14C]dipalmitoylphosphatidylcholine (phospholipid) by lysosomal soluble proteins was also examined. The effect of NMA on phospholipase A1 was assessed by the formation of lysophosphatidylcholine, and that on phospholipase C was assessed as the sum of mono- and diglyceride formations. The action of NMA on the phospholipid degradation was similar to that of cationic amphiphilic drugs, but it differed somewhat from that of chloroquine for each enzyme. From these results, it was concluded that one of the inhibitory mechanisms of phospholipid degradation by NMA was the direct interaction between NMA and phospholipase A1 or C.

Animals↗
PubMed1989

Inhibitory effects of quaternary ammonium compounds on lysosomal degradation of endogenous proteins.

The effects of quaternary ammonium compounds on the degradation of endogenous proteins in isolated lysosomes were studied. Proteolysis was assayed by measuring the trichloroacetic acid-soluble radioactivity in the lysosomes which had been labeled in vivo with 14C-leucine. p-Biphenylmethyl-(dl-tropyl-alpha-tropinium)bromide (BTTB), at concentrations higher than 0.85 mM, was found to inhibit the lysosomal proteolysis stoichiometrically. Other quaternary ammonium compounds, such as N-methylatropinium bromide (NMA), cetyltrimethylammonium bromide (CTAB), tubocurarine and gallamine, were also examined in the presence or absence of Triton X-100 which is able to destroy the lysosomal membranes. Of these four compounds, NMA was the most effective proteolysis inhibitor, showing 25% inhibition for intact lysosomes at a concentration of 1 mM of the compound. When these compounds were assayed after Triton X-100 treatment of the lysosomes, the effects of all the drugs were augmented, suggesting that they, after accumulation in the lysosomes, act through direct interactions with lysosomal proteases. This was supported by a kinetic analysis of the action of NMA on cathepsin B, a typical lysosomal protease.

Animals↗
PubMed1989

Three cases of acute massive hydrothorax complicating continuous ambulatory peritoneal dialysis (CAPD).

Acute hydrothorax is a rare complication of continuous ambulatory peritoneal dialysis (CAPD). We experienced three such cases among patients who started CAPD in our institute between April 1984 and April 1989. One was resolved with pleurodesis using autologous blood. The other two patients were switched to hemodialysis permanently because pleurodesis with autologous blood, tetracycline or OK432 failed. Acute hydrothorax is one important possible complication in CAPD.

Adult↗
PubMed1989

[A comparative study of the biological behavior of gastric cancer from the view of the amount of connective tissue in the cancerous tissue--a correlation between the amount of connective tissue and the metastatic pattern].

Differences between advanced gastric cancer of the medullary type (med.: 138 cases) and the scirrhous type (sci: 164 cases) with regard to the amount of connective tissue that was cancerous have been studied clinicopathologically. A correlation was found between med and liver metastasis, and sci and peritoneal dissemination in metastatic types, whereas no correlation was observed in other factors except between med and a localized type, sci and infiltrating type in gross type. The study of tumorigenicity in nude mice showed remarkable difference between med (86.7%) and sci. (0%). These results indicate that there is definite relationship between the amount of connective tissue and the biological behavior of a gastric cancer.

Adenocarcinoma, Scirrhous↗
PubMed1989

Rapidly progressive glomerulonephritis undetected by routine school urinalysis: a case report.

A twelve year old girl with rapidly progressive glomerulonephritis (RPGN) is reported. First symptoms of renal failure developed in August 1987 just five months after a routine school urinalysis which detected no abnormalities. The patient developed end stage renal failure within 2 months of onset. Continuous ambulatory peritoneal dialysis (CAPD) was introduced to manage the renal failure, and open renal biopsy was performed simultaneously in order to elucidate the underlying renal disease in this patient. Microscopic examination of the biopsy specimen demonstrated marked formation of crescents in about 90% of the glomeruli, and some of the glomeruli were already sclerotic. Granular depositions of IgG(trace), IgA(1+), IgM(3+), properdine(3+), Clq(3+) and C3(3+) were observed by immunofluorescence staining. A definite diagnosis of rapidly progressive glomerulonephritis was made as the cause of renal failure in this patient. It was suggested that open renal biopsy is useful in diagnosing the underlying kidney disease of end stage renal failure in cases where the clinical course is relatively short.

Child↗
PubMed1989

Continuous ambulatory peritoneal dialysis in a diabetic patient with renal insufficiency and ventricular aneurysm.

A diabetic patient with renal insufficiency and a giant ventricular aneurysm was treated by continuous ambulatory peritoneal dialysis (CAPD). No apparent exacerbation of the patient's cardiovascular function was observed after starting CAPD therapy, although his ejection fraction remained low and his angina attacks persisted. It is suggested that CAPD therapy has no deleterious effects on the cardiovascular system of patients with ventricular aneurysms, and that the benefits outweigh the risks.

Angina Pectoris↗
PubMed1989

[Studies on bond strength and hardness of base materials].

Since base materials are used in the construction of abutment teeth and the cavity walls of the teeth with healthy pulp, they need considerable bonding and mechanical strength depending on the site of application. In the present study we examined bonding strength, Martens-Mayer hardness and Vickers hardness of base materials in comparison with natural dentin in order to reevaluate them in terms of prosthetic materials and to provide assessment criteria for their application to prosthetic treatment. The results were as follows: 1) The bonding test showed the lowest value (4.6kgf/cm2) in calcium hydroxide FR (HFR) and the highest (47.9kgf/cm2) in HY-Bond polycarboxylate cement (CHC), a type of polycarboxylate cement. 2) In the test of bonding strength with various types of cement, calcium hydroxide preparations and zinc phosphate cement showed low values (4.6-23.5kgf/cm2) while polycarboxylate cement and glass-ionomer cement showed relatively high values (17.8-40.5kgf/cm2). 3) The Martens-Mayer hardness test showed the highest value (10.82 x 10(4] in dentin cement (GDE) and the lowest (1.09 x 10(4] in propack (EPR). 4) The Vickers hardness test showed the highest value (82) in neo-protect cement (ZPR) and the lowest (1) in propack (EPR). 5) In both Martens-Mayer and Vickers hardness tests with various types of cement, zinc phosphate cement and glass- ionomer cement showed high values, while low values were obtained in calcium hydroxide preparations and zinc-oxide eugenol cement. 6) Zinc phosphate cement and glass-ionomer cement showed no statistically significant differences from natural dentin in either Martens-Mayer hardness or Vickers hardness.

Dental Bonding↗
PubMed1989

Direct determination of four sulfates and seven glucuronides of 17-oxosteroids in urine by fluorescence "high-performance" liquid chromatography.

We describe a direct method for determining four sulfates and seven glucuronides of 17-oxosteroids (17OS) in urine without hydrolysis, by use of "high-performance" liquid chromatography (HPLC) with fluorometric detection. After pretreatment of urine samples with a Sep-Pak C18 cartridge, four 17OS sulfates and seven 17OS glucuronides in the pretreated urine samples were reacted with tetrapentylammonium ions to form ion pairs. Ion-paired 17OS sulfates were extracted with benzene. By adding sodium sulfate to the remaining sample, we could then extract ion-paired 17OS glucuronides with dichloromethane. Each extract was labeled with dansyl-hydrazine in an acetic acid-acetonitrile solution. The labeled steroids were separated by HPLC on a reversed-phase Capcell-Pak C8 (silicon-polymer-coated silica gel modified with octyl groups). We monitored each effluent with a fluorometric detector (330 nmexcitation, 535 nmemission).

17-Ketosteroids↗