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Biomedical subjects

H Okuda

Publications and source records attributed to H Okuda.

At least 379 records · Page 21Linked to original sources
PubMed1984

Purification and some properties of intracellular esterase from Pseudomonas fluorescens.

A novel esterase was found in Pseudomonas fluorescens cells and purified to homogeneity as determined by polyacrylamide gel electrophoresis. The esterase was extracted from the cells by freeze-thawing and hypotonic treatment. Purification was achieved by ammonium sulfate precipitation, followed by successive chromatographies on DEAE-cellulose and benzylamine-agarose and then electrophoresis. The enzyme catalyzed the hydrolysis of methyl esters, such as methyl butyrate, but its hydrolyzing activity decreased with increase in the chain length of the alcohol moiety, and it did not catalyze the hydrolysis of triacylglycerols, such as triacetin. In contrast, the enzyme acted on various acyl residues in a series of methyl esters, such as dimethyl succinate, methyl methacrylate, and dimethyl malate. The optimum pH for activity of this enzyme with methyl butyrate was 7.0-8.5. The enzyme was inhibited by phenylmethylsulfonylfluoride. Its molecular weight was estimated as 48,000 by molecular sieve electrophoresis and gel filtration on Sephadex G-150.

Chromatography, DEAE-Cellulose↗
PubMed1984

Correlation of lipolytic and lipogenic actions of synthetic peptides with structure.

The effects of various synthetic peptides on basal and ACTH-stimulated lipolysis in fat cells were examined. Glu-Arg-Gly-Phe-Phe-Phe possessed lipolytic activity and increased ACTH-stimulated lipolysis at concentrations higher than 0.5 mumol/ml. Glu-Arg-Gly-Phe-Phe-Tyr did not cause any release of FFA from fat cells. Glu-Arg-Gly-Leu-Leu-Leu had no lipolytic activity but inhibited ACTH-stimulated lipolysis at concentrations higher than 0.25 mumol/ml. Glu-Arg-Gly-Leu-Leu-Leu also inhibited epinephrine-stimulated lipolysis. The effects of the peptides on basal and insulin-stimulated lipogenesis in fat cells were examined. Glu-Arg-Gly-Phe-Phe-Tyr increased both basal and insulin-stimulated lipogenesis. A tripeptide, Glu-Arg-Gly, inhibited both basal and insulin-stimulated lipogenesis. Glu-Arg-Gly-Leu-Leu-Leu had no effect on either basal or insulin-stimulated lipogenesis. Glu-Arg-Gly-Phe-Phe-Phe and ACTH, which elicit FFA release from fat cells, also stimulated formation of [14C]triglyceride from [14C]glucose.

Adipose Tissue↗
PubMed1984

Effect of Brij 58 on the hydrolysis of methyl butyrate by lipase from Pseudomonas fluorescens.

Purified Pseudomonas fluorescens lipase [EC 3.1.1.3] exhibited slight activity on water-soluble esters such as methyl butyrate, and this activity was increased on addition of Brij 58 (20 oxyethylene hexadecyl ether) to the solution. This stimulating effect of Brij 58 on hydrolysis of various esters (dimethyl succinate, butyl n-acetate, and tributyrin) in aqueous solution was unspecific. Hydrolysis of methyl butyrate depended on the molecular ratio of Brij 58 to lipase, being maximal (about 8 times the basal level at 37 degrees C with 80 mM substrate in 0.1 M NaCl solution) with 30 mol of Brij 58 per mol of lipase. Comparative studies showed that all polyoxyethylene (POE) alkyl ethers tested, stimulated the methyl butyrate hydrolyzing activity and that the Adekatol SO series (dihydric normal alcohol ethoxylate) also stimulated the appreciably active, whereas Triton X-100, sodium cholate, sodium deoxycholate, sodium dodecylsulfate, POE, and fatty acids had no effect. Comparison of the effects of Brij 58 on the methyl butyrate hydrolyzing activities of various lipolytic enzymes indicated that its effect was specific for this lipase. Brij 58 had no detectable effect with emulsified esters, such as supersaturated methyl butyrate and triolein.

Animals↗
PubMed1984

Ca2+,Mg2+-ATPase of microsomal membranes from bovine aortic smooth muscle. Identification and characterization of an acid-stable phosphorylated intermediate of the Ca2+,Mg2+-ATPase.

An acid-stable phosphoprotein was formed in a microsomal membrane fraction isolated from bovine aortic smooth muscle in the presence of Mg2+ + ATP and Ca2+. The microsomes also showed Ca2+ uptake activity. The Ca2+ dependence of phosphoprotein formation and of Ca2+ uptake occurred over the same range of Ca2+ concentration (1-10 microM), and resembled similar findings from rabbit skeletal microsomes. The molecular weight of the phosphorylated protein, estimated by SDS-gel electrophoresis, was approximately 105,000. The phosphoprotein was labile at alkaline pH, and its decomposition was accelerated by hydroxylamine. Half-maximum incorporation of 32P in the presence of 10 microM Ca2+ occurred at 60 nM ATP. The calcium-dependent phosphoprotein formation was not affected by 5 mM NaN3, but was inhibited in a dose-dependent fashion by ADP with a 50% inhibition occurring at 180 microM. Fifty mM MgCl2 was required for the maximal phosphorylation. The rate of phosphoprotein decomposition after adding 2 mM EGTA was accelerated by varying the Mg2+ concentration from 10 microM to 3 mM. Alkaline pH (9.0) slowed the rate of phosphoprotein decay. Optimal Ca2+-dependent phosphoprotein occurred at 15 degrees C over a broad pH range (6.4 to 9.0). The activation energy of EGTA-induced phosphoprotein decomposition was 25.6 kcal/mol between 0 and 16 degrees C and 14.6 kcal/mol between 16 and 30 degrees C. The phosphoprotein formed by aortic microsomes was thus quite similar to the acid-stable phosphorylated intermediate of the Ca2+-transport ATPase of sarcoplasmic reticulum from skeletal and cardiac muscle. These data suggest that the Ca2+-dependent phosphoprotein is a reaction intermediate of the Ca2+,Mg2+-ATPase of the aortic microsomes.

Adenosine Diphosphate↗
PubMed1984

Dynamics of right heart flow in patients after Fontan procedure.

In seven patients who underwent Fontan procedures but in whom no valves were inserted, dynamics of right heart flow were evaluated with the use of a catheter-tipped velocity transducer, pulsed Doppler echocardiography, and angiocardiography. Right atrial (RA) contraction caused a forward flow to the pulmonary artery (PA) and a backward flow to the inferior vena cava (IVC). Backward flow to the superior vena cava (SVC) was minimal. As the right atrium relaxed, a rapid forward flow occurred at the IVC and SVC that filled the atrium and a small amount of pulmonary regurgitant flow was observed. Subsequently, a forward flow was observed at the IVC, SVC, and PA during RA diastole. Angiographically determined RA stroke volume (SV) was less than 40% of the left ventricular (LV) SV in three patients in whom the postoperative increase in atrial "a" wave pressure (delta p) was greater than 8 mm Hg, while it was similar to or greater than LVSV in four patients in whom delta p was 6 mm Hg or less. In all patients LV end-diastolic volume was 107 +/- 27(SD)% of normal but LV ejection fraction was 0.53 +/- 0.07, resulting in the reduced cardiac output (2.8 +/- 0.7 l/min/m2). There was no correlation between the RASV or RA ejection fraction and cardiac output. These data show that the RA contraction causes a forward flow to the PA and that pulmonary regurgitation is not significant after Fontan procedure even when valves are not inserted. Also, the postoperative increase in the RA afterload may depress RA function.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1984

Experimental studies on toxicity of ethylene glycol alkyl ethers in Japan.

Past studies on the toxicological effects of ethylene glycol alkyl ethers as well as the recent data on these chemicals in Japan are reviewed. Only a few researchers have participated in the study of ethylene glycol alkyl ethers in Japan. The effects of ethylene glycol alkyl ethers on testis and embryotoxic effects of ethylene glycol monomethyl ether (EGM) have been studied, as has the teratogenicity of ethylene glycol dimethyl ether (EGdM). Studies on ethylene glycol alkyl ethers and related compounds administered to mice by oral gavage revealed the occurrence of testicular atrophy and decreased white blood cell count by EGM, EGdM, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether and ethylene glycol monoethyl ether acetate, and the toxicity was related to their chemical structure. On the other hand, ethylene glycol, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monophenyl ether, ethylene glycol monoacetate or ethylene glycol diacetate showed no such an effect. Studies on EGM using hamsters or guinea pigs revealed the occurrence of testicular atrophy similar to that observed in mice. In regard to the methyl ethers of other glycols, there is no convincing evidence that propylene glycol monomethyl ether, diethylene glycol monomethyl ether or diethylene glycol dimethyl ether causes testicular atrophy in mice. Teratological studies of EGM and EGdM revealed embryotoxic effects in mice.

Abnormalities, Drug-Induced↗
PubMed1984

[Generation of hydrogen sulfide at excavation sites. I. A survey of job sites in the sewage system construction work].

It has long known that H2S is sometimes encountered during excavation in the Hiroshima delta. In order to secure information necessary to the improvement of working conditions in this area, we investigated the generation of H2S where work was being done on the Hiroshima sewage system. Using the shield method, we measured the concentration of H2S in the air around eight work sites, and we also measured pH, total sulfide, SO4(2-), C1-, Mg2+, and salinity in samples of water collected at the sites and from nearby wells. The ventilation volume was calculated from the measurement value of air movement with reference to ventilator capacity. The past situation of H2S generation at the sites was also investigated. The survey was conducted from August 30 to September 4, 1982, using the shield method. Concentrations of H2S from 0.8 to 7 ppm were detected in the air at four of the eight sites. Total sulfide varying from a trace to 8.5 mg/l was found at six sites, which included the four where H2S was found in the air. SO4(2-), C1-, and Mg2+ were found in high concentration in water in which sulfide was detected, and the same samples tended to have high salinity. At some of the sites, ventilation was implemented up to a maximum of 3,000 m3/h according to the concentration of H2S. At the sewage system construction sites covered in this survey, H2S concentration was kept below the permissible level of 10 ppm, and it may be concluded that adequate safety precautions have been taken.

Air Pollutants↗
PubMed1984

Clinicopathological features of hepatocellular carcinoma--comparison of hepatitis B seropositive and seronegative patients.

Clinicopathological features were studied in 113 non-alcoholic patients with histology-proven hepatocellular carcinoma, of whom 35 were positive for hepatis B virus surface antigen (HBsAg), 23 were negative for all seromarkers for hepatitis B virus, and 55 were negative for HBsAg, but positive for anti-HBs and/or anti-core antibody (anti-HBc) with low titers. It was found that the age of the patient at the time of diagnosis was significantly lower in HBsAg cases than in the other two groups. Serum alpha-fetoprotein levels were often normal or below 100 ng/ml in the seronegative cases, and its measurement less frequently served as a diagnostic clue. Otherwise, clinically there was no difference between the three groups except for more frequent liver disease within the second degree of kinship in the HBsAg patients. Histopathological study of the livers showed that there were more expanding type hepatocellular carcinomas in the seronegative cases as compared with the HBsAg positive cases. There was no autoimmune chronic liver disease in these patients. These observations and data seem to indicate that there are certain differences between HBsAg positive and seronegative hepatocellular carcinomas. Since most patients had progressive liver disease, it is likely that many of these seronegative cases had chronic non-A, non-B viral disease, which is very common in Japan. It may be inferred further that non-A, non-B hepatitis virus is less carcinogenic as compared with hepatitis B virus.

Adult↗
PubMed1984

Lipoprotein lipase-like activity in the liver of mice with Sarcoma 180.

The triglyceride lipase (TGL) activity of liver homogenates of mice with Sarcoma 180 was measured. The liver homogenate of normal or tumor-bearing mice was treated with 0.25% Triton X-100 and centrifuged at 100,000 g for 60 min, and the supernatant was applied to a heparin-Sepharose column. In normal mice, most of the TGL activities in the supernatant was eluted with 0.75 M NaCl from the column. In mice with Sarcoma 180, the TGL gave two peaks on heparin-Sepharose column chromatography, which were eluted with 0.75 M and 1.5 M NaCl, respectively. The activity in the first peak (0.75 M NaCl eluate) decreased; that in the second peak (1.5 M NaCl eluate) increased, and the ratio of the second peak to the first peak increased during tumor development. The livers of normal mice and mice on day 10 after tumor inoculation were perfused with heparin. The highest rate of the TGL release occurred within 1 min of heparin perfusion, and the bulk of heparin-releasable activity appeared within 2 min of perfusion in both normal and tumor-bearing mice. The TGL activity in liver perfusate of tumor-bearing mice, as well as that of liver homogenate, was resolved on a heparin-Sepharose column into two peaks, which were eluted with 0.75 M and 1.5 M NaCl, and most of the activity was eluted with 1.5 M NaCl. The nature of the TGL activity eluted from a heparin-Sepharose column was investigated. In both liver homogenates and liver perfusates, the first peak did not require serum for maximal activity and was relatively resistant to a high concentration of NaCl or protamine sulfate.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

[Effect of mazindol on obesity induced by administration of gold thioglucose].

The present experiments were carried out to elucidate the effect of mazindol feeding on obese mice made by gold-thioglucose injection. Mazindol was added to the diet at the level of 0.5, 2, 10 mg/kg body weight. It was found that oral administration of mazindol reduced the body weight gain and perimetrial adipose tissue weights increased in GTG-obese mice. Decreased adipose tissue weights were correlated with the decreased level of size and volume of fat cells. Basal lipolytic activity and adrenaline-induced lipolysis were also significantly decreased in mazindol groups as compared to those in GTG-obese mice that were not administered mazindol. These results indicate that the weight reduction induced by mazindol administration might not be due to increase in fat mobilization. The increased level of liver and serum lipid induced by GTG-obesity was also found to be improved by mazindol. Scanning electron micrographs indicated that the villous width of the small intestine were significantly smaller in the mazindol group that those in the GTG-obese group. Sucrase and esterase activities of the small intestine were also decreased by mazindol feeding as compared to those in the GTG-obese mice. based on these results mechanisms of action of mazindol were discussed.

Adipose Tissue↗
PubMed1984

Mechanisms of action of mazindol in preventing onset and development of obesity induced by gold thioglucose injection.

Biochemical and morphological studies were made on the role of mazindol in treatment of obesity in mice induced by gold thioglucose (GTG) injection. Mazindol was added to the diet at a level of 10 mg/kg body weight and then all animals were fed on a constantly restricted diet of 60 percent of the level of ad lib, food intake for 10 weeks. The following results were obtained: (1) The body weight and Lee's index were significantly increased by GTG injection and these increases in the GTG-obese group were reduced by oral mazindol. (2) The levels of triglyceride and cholesterol in the liver were much higher in the GTG-obese group than in the lean group, and were significantly less in the mazindol-treated group than in the GTG-obese group. (3) The levels of serum triglyceride and immunoreactive insulin were significantly higher in the GTG group than in the lean group and the increase in the GTG-treated animals was reduced by oral mazindol. (4) The size of fat cells and basal lipolytic activity in parametrial adipose tissue were greater in the GTG-obese group than in the lean group and were significantly reduced by mazindol treatment. (5) Disaccharidase activities in the small intestinal mucosa and the absorptive surface area of the mucosa were significantly greater in the GTG-obese group than in the lean group and were increased significantly less in the mazindol-treated group.

Adipose Tissue↗
PubMed1984

Quantification of individual serum bile acids in patients with liver diseases using high-performance liquid chromatography.

Using high-performance liquid chromatography combined with a column of immobilized 3 alpha-hydroxysteroid dehydrogenase, 15 bile acids, i.e., cholate, chenodeoxycholate, deoxycholate, lithocholate, ursodeoxycholate, and their five taurine conjugates and five glycine conjugates, were clearly separated and quantified in 38 patients with various hepatobiliary diseases and 9 normal controls. The serum levels of bile acids, both primary and total, were elevated in patients with liver disease, but did not differentiate between parenchymal disease and cholestasis. The ratio of cholate/chenodeoxycholate was significantly increased in cholestasis as compared with parenchymal liver injury. In primary biliary cirrhosis, the ratio of total glycine/taurine conjugates was decreased, with a marked increase of taurochenodeoxycholate. The bile acid pattern was distinctly different between extrahepatic cholestasis and primary biliary cirrhosis, which mainly reflects intrahepatic cholestasis. In acute hepatitis, there was a quick normalization of major taurine and glycine conjugates in the convalescent stage. Most of the major taurine and glycine conjugated bile salts were significantly elevated in cirrhosis, and the elevation of taurochenodeoxycholate was particularly marked in the decompensated state. Furthermore, the quantitative relationship between taurocholate and taurochenodeoxycholate in cirrhosis was reversed from that in acute hepatitis. These changes in absolute and relative concentrations of bile acids in various liver diseases perhaps reflect differing pathology and metabolism, and may prove diagnostic. Measurement of individual bile salts is easily and quickly done with this method, and may lend itself clinical application.

Adolescent↗
PubMed1984

[The indication and effect of radiation therapy in rectal carcinoma].

A total of sixty one patients with carcinoma of the rectum accepted radiotherapy of 40 Gy/4W to whole pelvis including the perineum. Randomized study of preoperative radiation to the pelvis showed that patients with advanced carcinoma of the lower rectum and the anus benefited in the prevention of the local recurrence and in the curability of unresectable tumor. Postoperative radiation therapy was indicated in the case of the residual tumor, metastatic lymphnodes, distinct lymphatic permeation and insufficient excision of the rectum. For the pelvic recurrence irradiation of doses more than 36 Gy was effective in the case of slow growing tumor. A radical treatment is expected for patients with inoperable tumor or for patients without indication of major surgery because of age or medical problems by the whole pelvic irradiation plus interstitial irradiation.

Adult↗