Biomedical subjects

H Ochi

Publications and source records attributed to H Ochi.

At least 217 records · Page 12Linked to original sources

PubMed1992

Roles of glutathione and glutathione peroxidase in the protection against endothelial cell injury induced by 15-hydroperoxyeicosatetraenoic acid.

We investigated the role of the glutathione redox cycle in endothelial cell injury induced by 15(S)-hydroperoxyeicosatetraenoic acid (15-HPETE), an arachidonate lipoxygenase product. Pretreatment of endothelial monolayers with reduced glutathione (GSH) markedly suppressed 15-HPETE-induced cellular injury, which was determined by the 51Cr-release assay. 15-HPETE-induced cytotoxicity was modified by several GSH-modulating agents such as buthionine sulfoximine and 2-oxothiazolidine-4-carboxylate, indicating that this cyto-protective action of GSH was correlated with the intracellular GSH level. These GSH-modulating agents also modified the conversion of 15-HPETE to 15(S)-hydroxyeicosatetraenoic acid by endothelial cells. On the other hand, the exposure of endothelial cell monolayers to 15-HPETE did not deplete intracellular GSH levels but decreased GSH peroxidase activity. In addition, sodium selenite and ebselen, a stimulator and mimic of GSH peroxidase activity, respectively, displayed remarkable protective effects against 15-HPETE-induced cytotoxicity. These results suggest that intracellular GSH plays a pivotal role in the protection against 15-HPETE-induced endothelial cell injury, and that the decreased activity of GSH peroxidase activity is involved in 15-HPETE-induced cytotoxicity.

Animals↗

PubMed1992

Effects of Y-20811, a thromboxane A2 synthetase inhibitor, on experimentally induced coronary thrombosis in anesthetized dogs.

The effects of Y-20811, a selective inhibitor of thromboxane A2 (TXA2) synthetase, on blood flow and local levels of immunoreactive thromboxane B2 (i-TXB2) and 6-keto prostaglandin F1 alpha (i-6-keto PGF1 alpha) in the coronary artery were investigated in the canine model of coronary thrombosis. Thrombosis was induced by applying an electric current to the intraluminal surface of the coronary artery. The plasma levels of i-TXB2 and i-6-keto PGF1 alpha were measured distal to the electrode. In the control group, coronary blood flow decreased and finally stopped 207 +/- 53 min (mean +/- S.E.M., n = 5) after the start of current application. The level of i-TXB2 rose before the coronary occlusion. Coronary blood flow did not change significantly in the Y-20811-treated group (1 mg/kg i.v.). The level of i-TXB2 decreased and remained significantly lower than that in the control group. The level of i-6-keto PGF1 alpha tended to increase slightly in the Y-20811-treated, but not in the control group. The weight of the thrombus in the Y-20811-treated group was significantly less than that in the control group (P less than 0.01). These results suggest that Y-20811 prevents coronary thrombosis by the inhibition of TXA2 production around the electrically injured lumen of the coronary artery.

6-Ketoprostaglandin F1 alpha↗

PubMed1992

Irreversible inhibition of thromboxane (TX) A2 synthesis by Y-20811, a selective TX synthetase inhibitor.

As Y-20811, sodium (+-)-4-[alpha-hydroxy-5-(1-imidazolyl)-2-methylbenzyl]-3,5-dimethylb+ ++ enzoic acid, has been reported to inhibit serum thromboxane (TX) A2 production with a long duration of action, its mechanism of action was investigated. When [3H]Y-20811 (3 mg/kg) was administered orally to rats, the peak platelet concentration of Y-20811 was obtained 1 hr after the administration, and the T1/2 was 43 hr. The peak plasma concentration of Y-20811 was also obtained 1 hr after administration, but the elimination of Y-20811 from plasma was faster (T1/2 alpha = 1.5 hr, T1/2 beta = 15 hr) than that observed in platelets. Serum TXA2 (estimated as TXB2) production was inhibited significantly from 1 to 72 hr after the oral administration of unlabeled Y-20811 (3 mg/kg), which temporally resembled the change of the platelet Y-20811 concentration. In platelet-rich plasma, [3H]Y-20811 completely inhibited TXA2 production at about 1500 pg/10(9) platelets, and the IC50 level was about 600 pg/10(9) platelets, which was similar to values obtained in ex vivo studies. In addition, inhibition of TXA2 production by Y-20811 still remained after washing the drug-pretreated microsomes, whereas that of dazoxiben completely disappeared. A similar irreversible inhibition of TXA2 production was observed with aspirin. These results suggest that Y-20811 may firmly combine with platelet TX synthetase and may irreversibly inhibit TXA2 production.

Animals↗

PubMed1992

Intraduodenal osmolality directly enhances insulin secretion in the rat.

To elucidate the direct effect of an intestinal osmolality on insulin release, we investigated the insulin response to intra-duodenal infusion of mannitol in rats. After the anesthesia with intraperitoneal pentobarbital sodium, one milliliter of mannitol solution (10% or 20%) was infused into the duodenum. Portal and femoral blood insulin concentrations significantly increased at 30, 60, and 120 min after intra-duodenal infusion of mannitol, although the blood glucose level did not change. Subcutaneous pre-administration of propranolol (0.4mg/kg) or metoprolol (25mg/kg) completely abolished this phenomenon. These results suggest that intestinal osmolality can directly enhance insulin secretion and that beta 1-adrenergic mechanism is involved in this phenomenon.

Adrenergic beta-Antagonists↗

PubMed1992

In vitro effects of glycosylated insulin in perfused liver and hindquarter in rats.

Using the perfused liver and hindquarter of the rat, the uptake of glycosylated insulin and its effect on glucose output were investigated. Insulin was glycosylated in ambient high glucose concentration, and glycosylated insulin GI80 (insulin incubated with 0.08% glucose), GI350 (incubated with 0.35% glucose), and GI1000 (incubated with 1% glucose) were prepared. The liver and hindquarter were perfused with nonglycosylated insulin (N-GI) or glycosylated insulin at a concentration of 100 or 1000 microU/ml. There were no significant differences in the fractional uptake of insulin by perfused liver and hindquarter despite glycosylation. Insulin-induced decrement in glucose output was significantly lower in the liver perfused with GI1000 than that in the liver perfused with N-GI, GI80, and GI350 at an insulin concentration of 100 microU/ml. There were no significant differences in insulin-induced decrement in glucose output between the hindquarter perfused with N-GI, GI80, GI350, and GI1000. These results suggest that when insulin (100 microU/ml) is incubated with a markedly elevated concentration of glucose (1000 mg/dl) its biological activity is reduced in the liver, but not in the hindquarter.

Animals↗

PubMed1992

Adrenergic mechanism in hyperketonemia in thyrotoxic and starved rats.

To evaluate the possible role of the adrenergic mechanism in hyperketonemia in hyperthyroidism and starvation, the plasma concentrations of FFA, acetoacetate (AcAc), and beta-hydroxybutyrate (BOHB) were measured in thyrotoxic and starved rats for 96 hours. Thyrotoxemia was induced in rats by a daily subcutaneous thyroxine (100 micrograms/kg/day) injection carried out for 7 days. Some of the thyrotoxic and starved rats were administered subcutaneous phentolamine (2 mg/kg, twice daily) or propranolol (0.1 mg/kg, twice daily). Plasma levels of FFA, AcAc, and BOHB were significantly increased in thyrotoxic and starved rats compared with the control rats. Phentolamine and propranolol administration did not alter plasma levels of FFA, AcAc, and BOHB in thyrotoxic rats. In starved rats, propranolol did not alter plasma levels of FFA, AcAc, and BOHB, however, phentolamine did increase plasma levels of FFA, AcAc, and BOHB. These results indicate that the adrenergic mechanism may not contribute to the hyperketonemia in thyrotoxic rats, but may have a slight inhibitory effect on ketogenesis in starvation probably due to alpha-antilipolytic action.

3-Hydroxybutyric Acid↗

PubMed1992

In vitro effects of glycosylated insulin and glucagon in perfused liver of the rat.

Using perfused liver of the rat, the hepatic uptake of glycosylated insulin (GI) and glucagon (GG) and its effects on hepatic glucose output were investigated. Insulin and glucagon were glycosylated in ambient high glucose concentration, and GI80 or GG80 (insulin or glucagon incubated with 0.08% glucose), GI350 or GG350 (incubated with 0.35% glucose), and GI1000 or GG1000 (incubated with 1% glucose) were prepared. The liver was perfused with the medium containing 1000 microU/ml insulin and 200 pg/ml glucagon or 200 microU/ml insulin and 1000 pg/ml glucagon. The fractional uptake of insulin or glucagon by perfused liver was not significantly altered by the glycosylation. In the liver perfused with 1000 microU/ml insulin and 200 pg/ml glucagon, glucose output was not changed by the glycosylation of the hormones, while in the liver perfused with 200 microU/ml insulin and 1000 pg/ml glucagon, GI1000 reduced its biological activity, as reflected by insulin-mediated decrease in glucose output. These results suggest that in the liver insulin incubated with markedly high concentration of glucose reduces its biological activity at a physiological concentration in the presence of high concentration of glucagon.

Animals↗

PubMed1992

Reduced bone density and major hormones regulating calcium metabolism in anorexia nervosa.

Bone density of lumbar vertebrae (L2 to L4) and the whole body in 29 patients with anorexia nervosa were measured by dual photon absorptiometry, and the results were compared with those of 10 age-matched normal controls. The patients had significantly lower bone mineral density (BMD) in L3 and L2-4 than controls. However, there was no difference in whole-body BMD. L3 and L2-4 BMD was positively correlated with body weight and was negatively correlated with duration of illness and amenorrhea. Patients who had been more active 6 months before the time of the study had significantly higher L3 BMD than the less active patients. Most patients had an abnormally low serum estrogen level, whereas the mean serum levels of thyroid hormone (T3, T4), cortisol, calcitonin, parathyroid hormone and vitamin D were within the normal range. No correlation was found between L3 or L2-4 BMD and the levels of these hormones. These results suggest that severe weight loss, low physical activity, longer duration of amenorrhea and deficiency of estrogen contribute to bone loss in patients with anorexia nervosa, whereas calcium-regulating hormones such as parathyroid hormone, calcitonin and vitamin D are unlikely to be a primary contributor to bone loss.

Adolescent↗

PubMed1992

Effects of a human antiflagellar monoclonal antibody in combination with antibiotics on Pseudomonas aeruginosa infection.

The in vivo activity of human immunoglobulin M monoclonal antibody IN-2A8, which is specific for flagellum type b of Pseudomonas aeruginosa, was evaluated in comparison to anti-O antigen (serotype B) MAb KO-2F2 and in combination with antibiotics. IN-2A8 showed stronger activity than KO-2F2 against subcutaneous infection in burned mice, while it was much less active against intraperitoneal infection in normal mice. In a burn infection model, IN-2A8 inhibited the increase of bacteria in skin lesions weakly and that in blood significantly, suggesting that it strongly suppressed bacterial spread to blood. The activity of IN-2A8 in combination with 10 antipseudomonal antibiotics against intraperitoneal infection was examined. Clear additive effect was observed with a combination of either carbapenem or aminoglycoside antibiotics in terms of mouse survival. The administration of an antibiotic, imipenem-cilastatin, simultaneously with or before that of IN-2A8 gave a combined effect, but the reverse order did not. The combination of IN-2A8 with imipenem-cilastatin decreased numbers of viable bacteria in the peritoneal cavity and blood and kept them low for a longer time than did either treatment alone. These results suggest that an antiflagellar monoclonal antibody would be effective against systemic infection in combination with some kinds of antibiotics.

Animals↗

PubMed1992

Binding of monoclonal antibody specific for domain Ia/II of Pseudomonas aeruginosa exotoxin A at pH 4 strongly neutralizes exotoxin A-induced cytotoxicity in cell culture and in vivo.

Mouse monoclonal antibodies (MAbs) against Pseudomonas aeruginosa exotoxin A (Ex-A) were established, and 4 of 20 MAbs were extensively studied for analysis of the structure-function relationship of Ex-A. IN vivo experiments demonstrated that MAb Ex-3C7 protected mice either injected with Ex-A or infected with Ex-A-producing P. aeruginosa from death caused by Ex-A at the highest rate, followed by MAbs Ex-4F2 and Ex-8H5, in that order. MAb Ex-2A10 failed to rescue the mice. MAb Ex-3C7 (immunoglobulin G1 [IgG1]) inhibited incorporation of Ex-A into target cells and strongly neutralized cytotoxicity in cell culture but did not inhibit an enzymatic activity of Ex-A, ADP-ribosyltransferase, at all. The MAb also bound Ex-A, even at a low pH of 4, and recognized amino acid residues 241 to 297 (domain Ia/II), suggesting that MAb Ex-3C7 can interfere with the conformational change and/or processing of Ex-A by keeping a complex of Ex-A and antibody stable at low pH in the phagolysosome. MAb Ex-4F2 (IgG1), which recognizes residues 550 to 590 (domain III), strongly inhibited Ex-A incorporation and neutralized cytotoxicity in cell culture but only weakly inhibited ADP-ribosyltransferase. MAb Ex-8H5 (IgG1), which recognizes residues 591 to 613 (domain III), also inhibited cytotoxicity in cell culture, but weakly. In contrast to the above three MAbs, MAb Ex-2A10 (IgG2b) greatly inhibited ADP-ribosyltransferase but showed no inhibition of Ex-A incorporation and no neutralizing activity against cell toxicity. A line of evidence indicates that (i) domain Ia/II plays an important role in the pathogenesis of Ex-A and (ii) MAbs that inhibit an intracellular postbinding process, such as conformational change, processing, and translocation of Ex-A in target cells, can display potent inhibitory activity against cytotoxicity in vivo, as well as in cell culture, and would be a good candidate for therapy of pseudomonal infections.

ADP Ribose Transferases↗

PubMed1992

[Quantitative evaluation of deglutition in the upper esophagus by scintigraphy].

To evaluate the function of deglutition quantitatively, radionuclide transit in the and upper esophagus was examined. Ten ml of water containing 185 MBq 99mTc pertechnetate was put into the mouth and isotopic counts were measured every 0.2 second in the oral cavity, upper and lower cervical esophagus, and upper mediastinum. The subjects were studied twice, once while sitting and once supine. Esophageal transit was evaluated with time-activity curves obtained in each region of interest. In twelve healthy volunteers transit of the radionuclide was significantly delayed in supine position compared with sitting position. Even while the subject was supine, the radionuclide was propelled into the lower cervical esophagus in 0.8 second and upper mediastinum in 1.4 second in the healthy volunteers. In the patient, who had reconstruction of the esophagus through posterior mediastinum, radionuclide transit was not different from that of healthy volunteers. Whereas in the patient, who had the reconstruction through retrosternal space, the transit was remarkably delayed. The esophageal scintigraphy was safe and sensitive enough to evaluated the function of deglutition quantitatively.

Adult↗

PubMed1992

Course before and after treatment of a patient with Budd-Chiari syndrome monitored by iodine-123-iodoamphetamine scintigraphy per os and per rectum.

A 55-yr-old woman with Budd-Chiari syndrome was treated by percutaneous transluminal angioplasty with a balloon catheter. Before and after treatment, portal scintigraphy was performed by the administration of [123I]iodoamphetamine per os and per rectum. An enteric capsule was used for the oral administration. Before treatment, the portal shunt index via the superior mesenteric vein was 40.5%; two weeks after treatment, it was 50.2%; and five months after treatment, it was 41.2%. Before treatment, the portal shunt index via the inferior mesenteric vein was 86.0%; two weeks after treatment, it was 87.6%; and five months after treatment, it was 21.8%. The treatment improved the portal circulation through the inferior mesenteric vein only, with little effect on the portal circulation through the superior mesenteric vein.

Amphetamines↗

PubMed1991

Superior vena cava flow and tricuspid anular motion after cardioversion of atrial fibrillation, and role of right atrial relaxation on systolic venous return.

To determine whether atrial relaxation or systolic descent of the tricuspid anulus is the predominant factor determining systolic venous return, 22 patients with atrial fibrillation were studied. Venous return (i.e., superior vena cava (SVC) flow) was measured using pulsed Doppler echocardiography. Systolic descent of the tricuspid anulus (i.e., total excursion of tricuspid anulus during systole) was also measured using echocardiography. Serial examinations were performed before and after cardioversion of atrial fibrillation in 15 patients. In 11 patients, both the total excursion of the tricuspid anulus and SVC flow were examined in relation to the ratio of the preceding to the pre-preceding RR interval (R2/R1). Systolic forward flow of SVC increased as the ratio of late diastolic to total excursion of the tricuspid anulus (i.e., right atrial systolic function) increased. It correlated significantly with the ratio of late diastolic to total excursion of the tricuspid anulus but not with total excursion. Total excursion of the tricuspid anulus correlated significantly with R2/R1, but systolic forward flow of SVC did not. These results indicate that atrial relaxation rather than systolic descent of the tricuspid anulus was the predominant factor determining systolic forward flow in the SVC.

Atrial Fibrillation↗

PubMed1991

Changes of common fragile sites on chromosomes according to the menstrual cycle.

The frequencies of chromosomal breaks and sister chromatid exchanges (SCE) are influenced by pregnancy, oral hormonal contraceptives and the menstrual cycle. The changes in the number and sites of spontaneous and aphidicolin-induced breaks on chromosomes from peripheral blood lymphocytes during the menstrual cycle were examined in 8 healthy women. Menstrual cycle was determined by menstruation and the quantity of serum estrogen, progesterone and luteinizing hormone. The number of spontaneous breaks at the follicular phase, the interval phase (which includes ovulation) and the luteal phase were 3.1 +/- 1.1, 2.7 +/- 2.3 and 3.9 +/- 2.6 per 100 mitoses, respectively. The frequencies of aphidicolin-induced breaks in the same phases were 95.8 +/- 23.3, 90.6 +/- 14.3 and 122.7 +/- 20.1 per 100 mitoses, respectively. The higher frequency at the luteal phase was statistically significant compared with the other phases. In the luteal phase, bands 2q32, 3q27, 6q26 and 16q23 had higher frequencies of breaks (P less than 0.05); however, breaks at band 9q32 decreased significantly. SCE showed considerable variation, but with no statistical significance.

Adult↗

PubMed1991

Hypereosinophilic syndrome appearing as a focal defect on liver scan.

The case reported here is of a 34-year-old man diagnosed as having hypereosinophilic syndrome. Blood tests showed a large increase in the number of eosinophils and a slight increase in aspartate aminotransferase and alkaline phosphatase. In scintigraphy of the liver with Tc-99m-phytate and with Ga-67-citrate, a focal defect was found in the outer part of the right lobe of the liver. Abdominal computed tomography showed a low density lesion in the same area. Histological inspection of the biopsy specimen showed heavy periportal infiltration with eosinophils. The results suggested that the focal defect seen in liver scintigraphy arose from a circulatory disturbance arising from infiltration by eosinophils.

Adult↗

PubMed1991

Production and characterization of human monoclonal antibody recognizing the N-terminal residues of Pseudomonas aeruginosa exotoxin A.

Human cell lines producing monoclonal antibodies (MAbs) against Pseudomonas aeruginosa exotoxin A were established by EBV transformation followed by cell fusion. Monoclonal antibody FK-001, IgM (mu, kappa), was demonstrated to be specifically reactive with exotoxin A in ELISA and immunoblotting, by recognizing N-terminal 16 amino acid residues of exotoxin A as an epitope. This epitope region belongs to domain I which is required for the binding of exotoxin A to the receptor on target cells. FK-001 showed a partial neutralizing activity for cell toxicity caused by exotoxin A and appeared to be effective against exotoxin A-producing P. aeruginosa infection in mice. A line of evidence suggests that monoclonal antibody FK-001 neutralizes exotoxin A-induced cell toxicity by the interference of accessibility and/or binding of exotoxin A to animal cell receptors.

ADP Ribose Transferases↗

PubMed1991

Measurement of hepatic blood flow by use of per-rectal portal scintigraphy with 133Xe.

A relatively noninvasive method is needed to evaluate the hepatic blood flow of patients with liver disease. We used per-rectal portal scintigraphy with 133Xe, and analysed the time-activity curves of the liver and portal vein. To do this, wash-out curves of the liver were plotted, and the hepatic blood flow and the ratio of the blood flow to the right lobe of the liver to that to the left lobe (R/L ratio) were calculated. The mean hepatic blood flow was 137 +/- 23 ml/100 g/min for four patients with fatty liver, 139 +/- 16 ml/100 g/min for seven patients with chronic persistent hepatitis, 120 +/- 15 ml/100 g/min for ten patients with chronic aggressive hepatitis, and 75 +/- 21 ml/100 g/min for 14 patients with cirrhosis. All seven patients with hepatic blood flow that was less than 100 ml/100 g/min and an R/L ratio less than 1.0 had cirrhosis. Only two of the 22 patients with hepatic blood flow that was greater than 100 ml/100 g/min and an R/L ratio greater than 1.0 had cirrhosis. Per-rectal portal scintigraphy can be used to measure the hepatic blood flow, but it was not useful for the diagnosis of fatty liver.

Administration, Rectal↗

PubMed1991

Serum lipid and apolipoprotein levels in non-hypertensive lean NIDDM patients.

To determine the possible role of a glycaemic control in lipid metabolism in non-insulin-dependent diabetes mellitus (NIDDM) patients, serum lipid and apolipoprotein levels were measured in well-controlled and poorly controlled lean NIDDM without proteinuria and hypertension. A sample of 96 lean NIDDM patients (body mass index less than 25 kg m-2 in men and less than 27 kg m-2 in women) were divided into two groups: group I, where the HbA1c concentration had been less than 6% for the previous 3 months, and group II, where the HbA1c concentration had been greater than 8% for the previous 3 months. Serum total cholesterol, triglyceride, and HDL-cholesterol levels showed no significant differences between groups I and II. Furthermore, serum levels of apolipoproteins AI, AII, B, CII, CIII, and E did not differ significantly between groups I and II. These results suggest that glycaemic control did not influence lipid metabolism in lean NIDDM patients.

Adult↗