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Biomedical subjects

K Okuda

Publications and source records attributed to K Okuda.

At least 739 records · Page 41Linked to original sources
PubMed1987

Splenic artery and superior mesenteric artery blood flow: nonsurgical Doppler US measurement in healthy subjects and patients with chronic liver disease.

The accuracy of the duplex Doppler ultrasound system in the measurement of blood flow in the splenic artery and the superior mesenteric artery was evaluated in seven anesthetized dogs by comparing blood flow recordings obtained simultaneously with the electromagnetic flowmeter, with those obtained with the combination of B-mode and M-mode scanning. Various flow rates were produced by the infusion of dopamine. Splenic artery blood flow and superior mesenteric artery blood flow measured with the duplex system exhibited significant correlations with corresponding values obtained with electromagnetic flow measurements (r = .93 and r = .93, respectively). Changes in splanchnic circulation with the progression of chronic liver disease in humans were then investigated with the use of the duplex system. Splenic artery blood flow and superior mesenteric artery blood flow were significantly increased in patients with cirrhosis compared with patients with chronic hepatitis and healthy subjects. These results indicate that a hyperdynamic circulatory state may develop in the splanchnic circulation of the intestine and spleen in cirrhotic patients.

Adult↗
PubMed1987

Splanchnic hemodynamics in portal hypertensive dogs with portal fibrosis.

Splanchnic hemodynamics and portal systemic shunting were measured in eight dogs with experimentally induced portal fibrosis and splenomegaly and in six normal dogs by the radioactive microsphere technique. Portal fibrosis and splenomegaly were produced by repeated intraportal injections of a mixture of killed nonpathogenic Escherichia coli and dog anti-E. coli serum. All E. coli-treated dogs developed intrahepatic presinusoidal portal hypertension (portal vein pressure 15.8 +/- 5.4 vs. 7.5 +/- 0.9 mmHg in controls, P less than 0.005; intrahepatic pressure 6.8 +/- 2.1 vs. 6.2 +/- 1.4 mmHg in controls, NS) within 2.5 mo, but no portal systemic shunt was demonstrated at this time (2.1 +/- 1.5 vs. 0.7 +/- 0.4%, NS). Portal venous inflow, the total blood flow within the portal system, was increased in the treated dogs (27.6 +/- 6.6 vs. 18.2 +/- 2.5 ml X min-1 X kg body wt-1, P less than 0.005). Total splanchnic arterial vascular resistance was reduced in these dogs (26.0 +/- 10.4 vs. 40.9 +/- 4.6 dyn X s X cm-5 X 10(3), P less than 0.01) as a result of reduced arteriolar resistance in the spleen, jejunum and ileum, colon, and omentum, in all of which blood flow increased. In these animals both portal venous flow (27.0 +/- 6.5 vs. 18.1 +/- 2.5 ml X min-1 X kg body wt-1, P less than 0.005) and intrahepatic portal vascular resistance (1.9 +/- 0.7 vs. 0.7 +/- 0.3 dyn X s X cm-5 X 10(3), P less than 0.005) were increased.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Antigenic heterogeneity of non-pigmented Bacteroides species isolated from the human oral cavity.

Serological studies on 27 strains of non-pigmented Bacteroides isolated from the human oral cavity revealed multiple serotypes within B. buccae. B. capillus (= B. buccae) and B. pentosaceus (= B. buccae) were found to be serogroups within B. buccae. B. denticola possessed cross-reactive antigens with B. buccae. Tested strains of B. oralis, B. veroralis, B. oris, and B. heparinolyticus were clearly differentiated from each other.

Antigens, Bacterial↗
PubMed1987

Drug oxidation activities of horseradish peroxidase, myoglobin and cytochrome P-450cam reconstituted with synthetic hemes.

Drug oxidations by horseradish peroxidase (HRP), myoglobin (Mb) and cytochrome P-450cam (P-450cam) reconstituted with synthetic hemes were studied in comparison with a form of cytochrome P-450 purified from liver microsomes of polychlorinated biphenyl (PCB)-treated rats. N,N-Dimethylaniline (DMA) and 7-isopropoxycoumarin were hardly dealkylated by the heme-substituted proteins in the presence of NADPH-cytochrome c (P-450) reductase and NADPH, while substantial activity of this kind was observed in the presence of hydrogen peroxide or cumene hydroperoxide as oxygen donors. Specific activity varied, depending on the substrates, oxygen donors, heme derivatives and apoproteins employed. Very high levels of activity were observed in hydrogen peroxide-dependent DMA N-demethylation with HRP substituted with certain hemes. The highest level of activity was about two hundred times as high as that of rat liver cytochrome P-450. The relationship between such activity and the chemical structure of heme derivatives was discussed.

Cytochrome P-450 Enzyme System↗
PubMed1987

Effects of brown rice on apparent digestibility and balance of nutrients in young men on low protein diets.

The effect of brown rice with low protein intake was studied in five healthy young men. Feces were weighed, the digestibility of nutrients was determined, and blood tests were made. Each subject followed a diet consisting mainly of polished rice for 14 days and one consisting mainly of brown rice for 8 days. Both diets contained 0.5 g protein per kg of body weight. The brown rice diet had 3 times as much dietary fiber as the polished rice diet. On the brown rice diet, fecal weight increased, and apparent digestibility of energy, protein, and fat decreased, as did the absorption rates of Na, K, and P. The nitrogen balance was negative on both diets, but more negative on the brown rice diet. The phosphorus balance on the brown rice diet was significantly negative, but other minerals were not affected by the diet. The levels of cholesterol and minerals in the plasma were not significantly different on the polished rice diet and the brown rice diet. Comparing these results with data on standard protein intake (Miyoshi, H. et al (1986) J. Nutr. Sci. Vitaminol., 32, 581-589.), we concluded that brown rice reduced protein digestibility and nitrogen balance.

Adult↗
PubMed1987

Orthotopic liver transplantation in dogs receiving FK-506.

Ten dogs that survived the perioperative events of liver transplantation were treated with 1 mg/kg/d oral FK. Eight of the recipients lived for at least 1 month postoperatively, and seven are still alive with normal hepatic function after 35 to 65 days. The consistency and good quality of results with this difficult transplant preparation using FK, in spite of its rumored great toxicity in dogs, have highlighted the importance of further developing the drug.

Animals↗
PubMed1987

Effect of famotidine on hepatic hemodynamics and peptic ulcer.

The acute effects of histamine H2 receptor antagonist, famotidine, on hepatic hemodynamics were studied in six normal volunteers and eight patients with chronic liver disease, and its chronic effects on peptic ulcer, portal hemodynamics, and hepatic function were studied in 20 patients with chronic liver disease and peptic ulcer (16 with gastric ulcer, four with duodenal ulcer). Infusion of 20 mg famotidine did not reduce hepatic blood flow and portal blood flow in normal subjects, nor did it reduce cardiac output, the gradient between wedged hepatic vein pressure and free hepatic vein pressure, hepatic blood flow, and portal blood flow in patients with chronic liver disease. An oral dose of 20 mg famotidine twice daily for 2 months healed peptic ulcer in 19 of 20 patients (95%) with chronic liver disease and peptic ulcer, without any change in portal blood flow and hepatic function. Thus famotidine does not appear to alter hepatic hemodynamics and hepatic function in normal subjects and patients with chronic liver disease.

Adult↗
PubMed1987

Effects of vasopressin on portal hemodynamics in patients with portal hypertension.

In view of the variability in the magnitude of the response of portal venous pressure to vasopressin in man, we investigated the effect of vasopressin on portal hemodynamics in seven patients with portal hypertension by simultaneous catheterization of the portal and the hepatic vein and the measurement of portal venous flow by an echo-Doppler flowmetry. Infusion of vasopressin (0.3 U/min) significantly decreased portal venous pressure (-36%), the gradient between portal venous pressure and free hepatic venous pressure (-50.6%), and portal venous flow (-54.3%) but did not reduce mean arterial pressure and pulse rate. Thus, vasopressin seems to decrease portal venous pressure by reducing portal venous flow.

Adult↗
PubMed1987

Changes of splanchnic circulation with progression of chronic liver disease studied by echo-Doppler flowmetry.

Changes that occurred in splanchnic circulation with the progression of chronic liver disease were investigated using an ultrasonic Doppler flowmeter in healthy adults and in patients with chronic active hepatitis and liver cirrhosis in the supine position after an overnight fast. Superior mesenteric venous flow, splenic venous flow, and portal venous flow were significantly increased in patients with liver cirrhosis but not in patients with chronic active hepatitis compared with normal subjects. Portal venous flow (control value 10.5 +/- 2.3 ml/min/kg body weight) minus the sum of superior mesenteric venous flow and splenic venous flow was 0.8 +/- 2.1 ml/min/kg body weight in the control, (0.1 +/- 1.9) in chronic active hepatitis, and (-2.2 +/- 4.3) in liver cirrhosis; the difference was significant between the control and cirrhosis groups. These results indicate that in patients with liver cirrhosis a hyperdynamic state occurs in the splanchnic circulation of the intestine and spleen and that some portion of splanchnic blood flow bypasses the liver into the systemic circulation.

Adult↗
PubMed1987

Analysis of alloantigen-specific suppressor T cells.

The intravenous administration of allogeneic spleen cells successfully induced two distinct subsets of alloantigen-specific suppressor T cells that function at either the induction phase or the effector phase of alloantigen-specific DTH responses. The induction phase suppressor T cells were found to be Lyt2-, and were not genetically restricted by H-2 region genes. The effector phase suppressor T cells are Lyt2+, and their activity is controlled by genes within the H-2 region. The effector phase suppressor T cells mediate antigen-dependent bystander suppression, provided the appropriate alloantigen is present at the site of the immune responses. This effector phase suppression requires cyclophosphamide-sensitive targets. The results of this study suggest that allospecific suppressor T cells and hapten-specific suppressor T cells have a similar mechanism of action.

Animals↗
PubMed1987

Delayed-type hypersensitivity to allogeneic mouse epidermal cell antigens. III. Analysis of suppressor cells.

The specificity of suppressor T cells (Ts cells) induced by intravenous administration of allogeneic spleen cells was studied in mice using a delayed-type hypersensitivity (DTH) assay. The DTH responses were induced by subcutaneous injection of allogeneic epidermal cells (ECs) and were assayed by footpad swelling. Afferent-phase Ts cells (Ts-aff cells) were transferred into the recipient mice before ECs immunization. Treatment with monoclonal anti-Thy-1.2 antibody and complement abolished the suppression by Ts-aff cells in the DTH response. The suppression induced by Ts-aff cells, however, was resistant to the treatment with monoclonal anti-I-A or anti-Lyt-2.2 antibody and complement. These results showed that Ts-aff cells were Lyt-2-, Ia- T cells. Efferent-phase Ts cells (Ts-eff cells) were transferred before challenge of the DTH assay. Phenotypic analysis of these Ts-eff cells showed them to be Lyt-2+, Ia- T cells. Studies using several strains of congenic mice revealed the antigen specificity of both Ts cell subsets. Adoptive transfer of Ts-eff cells required H-2 restriction, but Ts-aff cells did not. We also induced cognate suppression of the DTH responses to the alloantigens mediated by Ts-eff cells.

Animals↗
PubMed1987

The effect of 3-methylcholanthrene on postlanosterol cholesterol biosynthetic pathways in mouse skin.

Repeated topical application of 3-methylcholanthrene to the backs of BALB/c mice lowered the tissue levels of lathosterol and provitamin D3, intermediates in one of the cholesterol biosynthetic pathways (the delta 7 pathway), though the activities of lathosterol 5-desaturase and provitamin D3 7-reductase were similar to those of control animals. These results seemed to indicate that carcinogen treatment exerted a depressive effect at some earlier step(s) than lathosterol synthesis. However, the content of cholesterol in mouse skin was not lowered in these animals, suggesting that another biosynthetic pathway might be activated. When diazacholesterol, which is known to inhibit the conversion of desmosterol to cholesterol, was administered together with the carcinogen, a marked accumulation of desmosterol was observed compared to animals given only diazacholesterol. Since desmosterol is an intermediate in the pathway in which the delta 24 double bond is reduced at the final step (the delta 24 pathway), this seemed to suggest that the delta 24 pathway was activated by carcinogen treatment.

Administration, Topical↗