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Biomedical subjects

H Okuda

Publications and source records attributed to H Okuda.

At least 19 recordsLinked to original sources
PubMed1992

Fatty acid ethyl ester synthase in rat adipose tissue and its relationship to carboxylesterase.

Fatty acid ethyl ester (FAEE) synthase was obtained from rat adipose tissue in an electrophoretically homogeneous form. The enzyme associated with carboxylesterase activity was purified by acetone precipitation followed by successive chromatographies on DEAE-cellulose, phenyl-Sepharose, and Sephadex G-100 gel. The two activities in rat adipose tissue were associated as judged by their co-elution profiles, co-purifications at different steps, co-precipitations by antibody raised against purified FAEE synthase, and identical profiles of inhibition by diisopropyl fluorophosphate. The enzyme catalyzed the hydrolyses of both tri- and monoacylglycerols, and the susceptibilities of substrates increase with decreasing acyl chain length of the fatty acid moiety. Ethyl oleate-hydrolyzing activity was about one-eighth of the synthesizing activity. The N-terminal amino acid sequence of the first 27 residues of the purified enzyme was identical to that of the carboxylesterase from rat liver. With a polyclonal rabbit antibody against the rat adipose tissue FAEE synthase, the enzyme was demonstrated in the liver, lung, and testis, but not in the kidney. The antibody removed the FAEE-synthesizing activities in adipose tissue (86%), liver (23%), lung (62%), and testis (82%). These results suggest that carboxylesterase contributes to the nonoxidative ethanol metabolism (FAEE synthesis) in various organs.

Acyltransferases↗
PubMed1992

Glycosylation of lipoprotein lipase in human subcutaneous and omental adipose tissues.

Human adipose tissues from the abdomen (subcutaneous), thigh (subcutaneous) and omentum were incubated for 2 h with [35S]methionine. Then glycosylation of lipoprotein lipase (LPL) was analyzed by sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of endoglycosidase H (endo H)-digested subunits of the 35S-labeled lipase. Adipose tissues from the abdomen, thigh, and omentum all synthesized LPL subunits with Mr = 57,000 composed of two types of subunits. One type was partially endo H-sensitive yielding a product with Mr = 55,000, indicating that it had one endo H-resistant and one endo H-sensitive oligosaccharide chain. The other type of subunit was totally endo H-sensitive yielding a product with Mr = 52,000. Subcutaneous adipose tissues contained nearly equal amounts of partially and totally endo H-sensitive subunits of LPL, whereas omental adipose tissues contained mainly partially endo H-sensitive subunits of LPL.

Adipose Tissue↗
PubMed1992

Changes of plasma des-gamma-carboxy prothrombin levels in patients with hepatocellular carcinoma in response to vitamin K.

The effect of menaquinone-4 (MK-4, vitamin K2) was studied on des-gamma-carboxy prothrombin (DCP or PIVKA-II) levels in three subjects with vitamin K deficiency and five patients with hepatocellular carcinoma (HCC) with positive DCP. The half-life of DCP in HCC patients after intravenous MK-4 administration (50 mg daily for 14 days) was determined to be 60 hours, identical to that found in vitamin K-deficient subjects who received MK-4. When a single dose of MK-4 (10 mg) was given intravenously to three patients with HCC and elevated DCP, the levels decreased with a reduction rate identical to that in vitamin K-deficient subjects for the first 1 to 3 days, followed by an increase reaching the previous level in 7 to 10 days. Changes in plasma coagulant activity were compared between subjects with vitamin K deficiency and those with HCC before and after a single dose of MK-4 (10 mg). The activity increased in DCP-positive patients with HCC as in vitamin K-deficient subjects who received the same single dose of MK-4. The increase was greater in HCC patients with higher DCP levels. These results suggest that the level of plasma DCP in patients with HCC responded to vitamin K with the same sensitivity as that in vitamin K-deficient subjects. When patients with HCC underwent effective tumor therapy (resection or arterial embolization), the reduction rate (slope of DCP decline) was found to be identical to that in vitamin K-deficient subjects given with MK-4. In patients with less effective therapy, the reduction rate was smaller, or there was an increase in DCP. These observations strongly suggest that sequential measurements of the DCP reduction rate after treatment for HCC are useful for assessing therapeutic effects.

Aged↗
PubMed1992

A case of splenic vein occlusion caused by the intravenous tumor thrombus of nonfunctioning islet cell carcinoma.

We report herein a case of successfully treated advanced, nonfunctioning islet cell carcinoma associated with left-sided portal hypertension. The splenic vein was obstructed by a huge intravenous tumor thrombus developing from the main pancreatic tumor. Direct invasion to adjacent organs such as the spleen, colon, left kidney and stomach was also observed, although liver metastasis was not present. Radical resection was carried out with removal of these five involved organs and the patient is alive without recurrence more than 5 years after surgery.

Adenoma, Islet Cell↗
PubMed1992

Anorexia induced by toxohormone-L isolated from ascites fluid of patients with hepatoma.

To ascertain anorexigenic effect of toxohormone-L, a polypeptide extracted and purified from ascites of patients with hepatoma were infused into the rat third cerebroventricle. Food intake decreased on the first day after infusion of an optimum dose of 10.0 micrograms (p less than 0.05). The suppressive effect on feeding was linearly dose dependent (p less than 0.05). Meal size and latency to the first meal decreased in the 12-h dark period, and the first and the second 4-h cumulative blocks after infusion of a 10.0 micrograms dose (p less than 0.01 for each). The suppressive effects on total food intake and meal size were completely recovered within 24 h after infusion. Neither postprandial intermeal interval nor eating speed was affected. Periprandial drinking, a ratio of water intake to food intake, was not affected after infusion of 5.0 and 10.0 micrograms toxohormone-L. Infusion of a 10.0 micrograms dose showed no effect on ambulation. These findings suggest that anorexia and cachexia produced in cancer patients may essentially be due to the suppressive effect of toxohormone-L on food intake.

Animals↗
PubMed1992

Effect of diolein on hydrolysis of phosphatidylcholine by phospholipase C from Clostridium perfringens.

The activity of phospholipase C from Clostridium perfringens on 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) as a monolayer at an air/water interface was examined. With a pure POPC monolayer, sharp cut-off of the enzyme activity was observed on increase in surface pressure. However, this cut-off disappeared on addition of a 0.3 molar fraction of 1,2-dioleoylglycerol (1,2-DO) to the monolayer. An abrupt change in the enzyme activity was observed with molar fractions of between 0.2 and 0.3 1,2-DO in the POPC monolayer at an initial surface pressure of 35 mN/m. For examination of the effect of 1,2-DO on the phospholipase C activity, the quantity of [125I]phospholipase C adsorbed to the surface was determined. The enzyme was found to be adsorbed nonspecifically to all lipid films except that of POPC only. The adsorption of enzyme was not affected by the presence or absence of Ca2+ and Zn2+. The rate constant for enzyme adsorption to a 1,2-DO film was 4.5 times that for its adsorption to a POPC film. The adsorption decreased linearly with increase in the surface concentration of POPC, and increased with increase in the surface concentration of 1,2-DO. These data suggest that 1,2-DO (a reaction product) regulates the interaction of phospholipase C with films containing substrate and may also regulate the enzyme activity.

Clostridium perfringens↗
PubMed1992

Tolerance to the convulsions induced by daily nicotine treatment in rats.

Development of tolerance to the nicotine-induced convulsions in rats was examined. Acute intraperitoneal (i.p.) administration of nicotine (2.5, 3.75 and 5 mg/kg) produced convulsions in a dose-dependent manner. Mecamylamine (1 mg/kg, i.p.) antagonized the convulsions, but hexamethonium (5 mg/kg, i.p.) did not modify them. Daily nicotine administration (2.5, 3.75 and 5 mg/kg, i.p.) once a day for 6 days developed tolerance to the convulsions induced by nicotine. After the daily administrations of nicotine for 6 days, the effects of a challenge administration of nicotine (2 mg/kg) on the nicotine-induced convulsions were tested on the 7th-day. Further tolerances were also developed by the 7th-day challenge administration. After the 7th-day test, nicotine levels of the brain and blood 15 min after the challenge injection were measured. With nicotine (5 mg/kg once a day)-treatment, nicotine levels of all the brain regions were increased. In contrast, a similar challenge injection had no effect on blood nicotine level. These results indicate that the development of tolerance to the nicotine-induced convulsions is produced relatively earlier and day by day by daily administrations to rats, which is closely related with the increase in brain nicotine level.

Animals↗
PubMed1992

Effects of acute administration of nicotine on convulsive movements and blood levels of corticosterone in old rats.

The convulsive movements, blood levels of corticosterone and pharmacokinetics of nicotine after an acute intraperitoneal injection of nicotine (5 mg/kg) were examined in young (6-week-old) and old (2-year-old) rats. In pharmacokinetic study, blood nicotine levels during the elimination phase were significantly higher in old rats than in young rats. However, the duration of convulsions and the elevation of corticosterone levels after the nicotine injection showed significant decreases in old rats compared with those in young rats. These differences of nicotine-induced responses between young and old rats may be involved in the decrease in nicotine sensitivity.

Aging↗
PubMed1992

Standardized lateral oblique projection of the mandible for digital subtraction radiography.

A special apparatus was developed for standardization of the lateral oblique projection of the mandible (LOPM) in order to apply the digital subtraction method. Geometric reproducibility was examined over an 8-week period using a dry skull. Angulation errors were determined by the relation to image noise in the subtraction image. It was found that the relation between image noise and angulation error was approximated by a second-order polynomial. Geometric reproducibility was within 1 degree over the experimental period. These results suggest that this standardized LOPM is satisfactory for clinical application of digital subtraction. Two cases are presented where this technique was used to demonstrate longitudinal changes in bone density.

Adult↗
PubMed1992

Relationship between cyclic AMP production and lipolysis induced by forskolin in rat fat cells.

Forskolin (7 beta-acetoxy-8, 13-epoxy-1 alpha,6 beta,9 alpha-trihydroxy-labd-14-ene-11-one) induced both cyclic AMP production and lipolysis in intact fat cells, but stimulated lipolysis without increasing cyclic AMP at a concentration of 10(-5) M. Homogenization of fat cells elicited lipolysis without elevation of cyclic AMP. Forskolin did not stimulate lipolysis in the homogenate. Forskolin stimulated both cyclic AMP production and lipolysis in a cell-free system consisting of endogenous lipid droplets and a lipoprotein lipase-free lipase fraction prepared from fat cells. However, at a concentration of 10(-6) M, it induced lipolysis without increase in the cyclic AMP content in this cell-free system. In the cell-free system, homogenization of the lipid droplets resulted in marked increase in lipolysis to almost the same level as that with 10(-4) M forskolin without concomitant increase in cyclic AMP. Addition of forskolin to a cell-free system consisting of homogenized lipid droplets and lipase did not stimulate lipolysis further. Phosphodiesterase activities were found to be almost the same both in the presence and absence of forskolin in these reaction mixtures. Although 10(-3) M forskolin produced maximal concentrations of cyclic AMP: 6.7 x 10(-7) M in fat cells and 2.7 x 10(-7) M in the cell-free system, 10(-4) M cyclic AMP did not stimulate lipolysis in the cell-free system. In a cell-free system consisting of lipid droplets and the lipase, pyrophosphate inhibited forskolin-induced cyclic AMP production, but decreased forskolin-mediated lipolysis only slightly. Based on these results, mechanism of lipolytic action of forskolin was discussed.

Adipose Tissue↗
PubMed1992

Retention of glucose by N-linked oligosaccharide chains impedes expression of lipoprotein lipase activity: effect of castanospermine.

The effect of castanospermine (CSTP), an inhibitor of glucosidase I, on processing, activity, and secretion of lipoprotein lipase was studied in 3T3-L1 adipocytes. Processing was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of endoglycosidase H (endo H)-digested subunits of lipoprotein lipase from cells incubated 1-2 h with [35S]methionine. Lipoprotein lipase in untreated cells consisted of two groups of subunits, M(r) = 55,000-58,000 and M(r) = 53,000-55,000. The heavier subunits were endo H-resistant, whereas the others were either totally or partially endo H-sensitive. The lipase secreted by untreated cells contained primarily endo H-resistant subunits. Immunofluorescent studies showed that lipoprotein lipase accumulated in Golgi in untreated cells. CSTP, 100 micrograms/ml for 18 h, decreased intracellular lipase activity by 80% and decreased secretion of lipase activity by 91%. Most of the lipase subunits in CSTP-treated cells were totally endo H-sensitive with M(r) = 57,000, some were partially endo H-sensitive, and a trace was endo-H resistant. Totally endo H-sensitive subunits in CSTP-treated cells had a M(r) 2,000-4,000 larger than that in untreated cells, indicating impaired trimming of sugar residues from oligosaccharide chains of the lipase in CSTP-treated cells. The small amount of lipase secreted by CSTP-treated cells consisted primarily of partially endo H-sensitive subunits, with one sensitive and one resistant chain per subunit. Immunofluorescent studies showed that lipoprotein lipase was excluded from Golgi in CSTP-treated cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗
PubMed1992

Statistical analysis of relationship between net protein utilization in rat and amino acid composition in cooked foods.

To determine the relation between protein nutritive value and amino acid composition of protein in cooked food, statistical analysis was carried out on thirty cooked foods selected from Japanese daily meal. The food samples were cooked, and powdered after freeze-drying. The amino acid composition was determined by liquid chromatography and colorimetry. The Wistar rats were put on the 7% cooked food protein diet and NPU (net protein utilization) was determined. Linear multiple regression analysis was made between NPU and the ratio of individual essential amino acid in the cooked food protein (mg/Ng)/the corresponding amino acid in the reference protein (mg/Ng). The regression equation for the predicted net protein utilization (NPUp) reads as follows: [formula: see text] Highest correlation coefficient (r = 0.93, p < 0.01) was obtained between NPU and NPUp of the protein in the cooked food.

Algorithms↗
PubMed1992

[Primary effect of preoperative intra-arterial infusion chemotherapy in cervical cancer].

In order to obtain better prognoses for cervical cancer, we conducted preoperative intra-arterial (i.a.) infusion chemotherapy of CDDP in combination with AT-II pressor. Two courses of i.a. chemotherapy were performed for 67 patients with cervical cancer in stage IIb containing 54 squamous cell carcinomas and 13 adenocarcinomas before operation every 3 weeks. A histologically desirable effect in cervical lesion was obtained. A group given preoperative i.a. chemotherapy had a significantly lower rate of infiltration beyond uterus in comparison with 156 patients with 145 squamous cell carcinomas and 11 adenocarcinomas treated by surgery alone as the control group. Further, the rate of histological infiltration to parametrial edges after i.a. chemotherapy tended to be lower than the control group. From the above, it was considered that preoperative i.a. infusion chemotherapy of CDDP in combination with AT-II pressor for cervical cancer was effective as a neo-adjuvant chemotherapy.

Adenocarcinoma↗
PubMed1991

Changes in the latency of the maximum positive peak of visual evoked potential during anesthesia.

The relationship between the latency of visual evoked potential (VEP) and the anesthetic concentration was investigated in surgical patients in order to examine the applicability of VEP in monitoring of the depth of anesthesia. The VEP was recorded with a standard EEG electrode from the midline parietal region in reference to both earlobes linked to the ground. An array of light-emitting-diodes mounted in opaque goggles was used to stimulate both eyes simultaneously and photic stimuli were delivered at random inter-pulse intervals with uniform distribution ranging from 2 to 5 seconds. Fifty trials of data were averaged to estimate that Pmax latency, i.e., the latent period from the photic stimulus to the maximum positive peak arising after 170 msec. Increases in the Pmax latency following the administration of anesthetics and restorations to preanesthetic values after recovery from anesthesia were found. A significant correlation was demonstrated between the Pmax latency and the inspiratory concentration of enflurane. The latency of the Pmax showed a drastic and a sensitive prolongation from about 200 msec in the awake state up to about 600 msec at the stage where the EEG exhibits large-voltage slow waves. Thus the measurement of the Pmax latency of VEPs was found to be useful for monitoring the depth of anesthesia.

Anesthesia↗
PubMed1991

A quantitative analysis of hemodynamic effects of the right ventricle included in the circulation of the Fontan procedure.

BACKGROUND: Right heart hemodynamics were analyzed with a catheter-mounted velocity meter in seven patients after direct atrioventricular anastomosis for Fontan procedure (RV group) and were compared with those obtained in eight patients after direct atriopulmonary anastomosis (RA group). METHODS AND RESULTS: In the RV group, cardiac output was 2.7 +/- 0.6 l/min/m2; mean right atrial and pulmonary artery pressures were both 13 +/- 3 mm Hg; mean pulmonary artery wedge pressure was 7 +/- 5 mm Hg; left ventricular end-diastolic volume, determined angiographically, was 129 +/- 40% of normal; and its ejection fraction was 0.50 +/- 0.09. In the RA group, data were similar to those of the RV group except that right heart pressure were lower in the RV group, which was related to the preoperative condition of the pulmonary circulation. In the RV group, the fraction of ventricular forward flow of the total forward flow in the main pulmonary artery ranged from 0.21 to 0.46 and was not correlated with cardiac output or with any other parameter. The backward flow into the inferior vena cava at ventricular systole was greater than the atrial flow in two patients in whom cardiac output was less than 2.2 l/min/m2, whereas caval backward flow at atrial contraction was greater than ventricular flow in the other five patients, of whom four had a cardiac output greater than 3.1 l/min/m2. CONCLUSIONS: We conclude that the inclusion of right ventricle in the circulation of the Fontan procedure does not necessarily improve overall hemodynamics in most patients.

Adult↗