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Biomedical subjects

Y Ohtani

Publications and source records attributed to Y Ohtani.

At least 127 records · Page 7Linked to original sources
PubMed1990

[Evaluation of correlation between the disappearance rate of indocyanine green and the maximum removal rate].

The disappearance rate of indocyanine green (K.ICG) and the maximum removal rate (Rmax) usually correlate with each other. However, in some cases it was shown there was a dissociation between them. We investigated the relationship between the two rates in 146 subjects. K.ICG and Rmax correlated strongly with a correlation coefficient of 0.749 (p less than 0.001). Sixty-six cases were included in the limits of 95% confidence, and the other 80 cases outside the limits were defined as dissociated cases. Among them a lower Rmax rate as compared to the K.ICG rate was found in many cases of obstructive jaundice. Particularly a lower K.ICG rate compared to the Rmax rate was found in many cases of liver cirrhosis accompanied by esophageal varices and idiopathic portal hypertension. On the other hands, we performed multiple regression analysis on 12 other liver function tests. K.ICG was strongly related to platelet count, circulatory blood volume, and albumin, all factors relating to portal hypertension. Rmax largely depended on LCAT, A/G ratio, and cholinesterase, which are Therefore, the dissociation between K.ICG and Rmax was caused by differences in the characteristic of each disease.

Cholestasis↗
PubMed1989

Differential effects of alpha-, beta- and gamma-cyclodextrins on human erythrocytes.

Alpha-, beta- and gamma-cyclodextrins are cyclic hexamers, heptamers, and octamers of glucose, respectively, and thus are hydrophilic; nevertheless, they have the ability to solubilize lipids through the formation of molecular inclusion complexes. The volume of lipophilic space involved in the solubilization process increases with the number of glucose units in the cyclodextrin molecule and, consequently, cyclodextrins were found to have different effects on human erythrocytes: (a) in the induction of shape change from discocyte to spherocyte the potency was observed to be alpha greater than gamma, but with beta-cyclodextrin hemolysis occurred before the change was complete; (b) in the increase of fluorescence intensity of 1-anilinonaphthalene-8-sulfonate in cyclodextrin-pretreated membranes, the observed potency was beta much greater than gamma greater than alpha; (c) in the release of potassium and hemoglobin, the potency was beta greater than alpha greater than gamma. The potencies of cyclodextrin for solubilizing various components of erythrocytes were alpha greater than beta much greater than gamma for phospholipids, beta much greater than gamma greater than alpha for cholesterol and beta much greater than gamma greater than alpha for proteins. The solubilization potencies were derived from concentration/final-effect curves. The above processes occurred without entry of solubilizer into the membrane, since (a) beta-[14C]cyclodextrin did not bind to erythrocytes and (b) cyclodextrins did not enter the cholesterol monolayer. A study of the [3H]cholesterol in erythrocytes indicated that beta-cyclodextrin extracted this lipid from membrane into a new compartment located in the aqueous phase which could equilibrate rapidly with additional erythrocytes. Therefore, the effects of cyclodextrins differ from those of detergents which first incorporate themselves into membranes then extract membrane components into supramolecular micelles.

Cyclodextrins↗
PubMed1989

Subcellular distribution of the transmissible agent in Creutzfeldt-Jakob disease mouse brain.

To determine the intracellular localization of the Creutzfeldt-Jakob disease (CJD) agent in mouse brain, cerebrum tissue of the mouse brain affected with the Fukuoka-1 strain was separated into six subcellular fractions (microsome, nerve ending, myelin, mitochondria, nucleus, and soluble fractions) by differential sucrose density gradient, and then the CJD infectivity of these fractions was examined. Serially diluted samples of each subfraction were inoculated intracerebrally into groups of BALB/c mice, and the infectivity was determined as to end point titration value, incubation period, and number of affected mice. On the basis of the protein content, the highest CJD infectivity was observed in the microsomal fraction. The nerve ending (synaptic plasma membrane) and myelin fractions were also infective. The mitochondria and nucleus fractions showed the lower infectivity. The infectivity of the soluble fraction was the lowest among the six subcellular fractions. From the findings obtained in this study two possibilities as to the intracellular localization of CJD agent were suggested: 1) the transmissible agent of CJD is closely associated with surface membranes of neuronal and/or glial cells, including their processes; 2) the CJD agent is diffusely present intracellularly, including in the surface membranes, but for manifestation of infectivity the agent needs membrane components as prerequisite factors.

Animals↗
PubMed1989

Analysis of endotoxin fever in rabbits by using a monoclonal antibody to tumor necrosis factor (cachectin).

A murine monoclonal antibody to rabbit tumor necrosis factor (TNF; cachectin) was injected intravenously into an endotoxin-treated rabbit to examine the role of endogenous TNF in fever. Both early and late peaks of biphasic fever evoked by the endotoxin injection were suppressed by the antibody. TNF activity was detected in an endotoxin dose-dependent manner in the blood 1 h after the endotoxin injection, which was coincident with the early-peak fever. Although the late-peak fever responded to the antibody, no significant TNF activity was detected in the blood obtained 1 h before the peak response. The blood was found to contain endogenous pyrogen activity, which was stable after heating at 70 degrees C for 30 min and resistant to in vitro treatment with the antibody. Rabbit TNF injection also elicited biphasic fever in rabbits, the second phase of which was found to be mediated by the similar endogenous pyrogen. These results suggest that endogenous TNF plays an important role in eliciting a febrile response to endotoxin.

Animals↗
PubMed1989

Analysis of simple reaction time to a sinusoidal grating by means of a linear filter model of the detection process.

Simple reaction time (RT) to a sinusoidal grating was analyzed in terms of a linear filter model of the detection process. First, RT contrast functions were determined over a wide range of spatial frequencies and retinal illuminances. Second, calculating the time course of the linear filter's response, theoretical visual latency contrast functions were derived for the same conditions of spatial frequency and retinal illuminance as those in the RT measurements. Comparison of the two functions showed that the contrast dependence of the RT functions was much larger than that of the visual latency functions. The discrepancy between the two functions was satisfactorily described as a power function of the slope of the filter's response at threshold level. On the basis of these results, we propose a model of the RT process. According to the model, the RT process is mediated by a cascade that consists of a level detector, which includes a linear filter followed by a threshold device, and a differentiator of the filter's response.

Attention↗
PubMed1989

[A case of mitochondrial encephalomyopathy with cardiomyopathy due to decreased complex I and IV activities].

We reported a girl with mitochondrial encephalomyopathy, who had various neuromuscular symptoms including dilated cardiomyopathy, generalized convulsions, myoclonus, muscular weakness and growth retardation. Lactate levels in the serum and CSF were elevated. Muscle biopsy showed scattered ragged-red fibers, and complex I (NADH-CoQ reductase) and complex IV (cytochrome c oxidase) were markedly reduced. Although she was treated with coenzyme Q, DL-carnitine and sodium succinate, she died of progressive congestive heart failure at 9 10/12 years of age.

Cardiomyopathy, Dilated↗
PubMed1988

Some properties of a proteolytic enzyme from the venom of Agkistrodon caliginosus (kankoku-mamushi) which increases capillary permeability.

The molecular weight of the capillary permeability-increasing enzyme from the venom of A. caliginosus was estimated to be about 32,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. This enzyme consists of a single polypeptide chain with an isoelectric point of pH 4.80. The enzyme is composed of 266 amino acid residues, based on a molecular weight of 32,000, and contained 11.4% carbohydrate. The enzyme more readily hydrolyzed arginine esters than lysine esters and did not hydrolyze tyrosine ester. Both the arginine ester hydrolytic and capillary permeability-increasing activities were inhibited by treatment with diisopropylfluorophosphate, indicating that the enzyme is an arginine esterase of the serine proteinase type. The substrate specificity of the enzyme toward synthetic chromogenic or fluorogenic substrates for mammalian serine proteinases and the pH and heat stabilities of the enzyme were also investigated.

Amino Acids↗
PubMed1988

Purification of a kininogenase from the venom of Agkistrodon caliginosus (Kankoku-Mamushi).

During the isolation of a capillary permeability-increasing enzyme from the venom of A. caliginosus, a kininogenase was also purified from the venom by gel filtration on Sephadex G-100, ion-exchange chromatographies on CM-Sephadex C-50 and DEAE-Sephadex A-50, and gel filtration on Sephadex G-75. By this procedure, 11 mg of the purified enzyme were obtained from 4 g of the venom. The purified enzyme was homogeneous by polyacrylamide disc gel electrophoresis at pH 8.3 and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and did not show any caseinolytic or clotting activity. The purified enzyme released bradykinin from purified bovine high mol.wt kininogen. The capillary permeability was increased by injection of the purified enzyme into the depilated skin of the back of a rabbit. It is supposed that the capillary permeability-increasing activity exerted by the enzyme is due to the release of bradykinin.

Animals↗
PubMed1988

Some properties of a kininogenase from the venom of Agkistrodon caliginosus (Kankoku-Mamushi).

A kininogenase (bradykinin-releasing enzyme) from the venom of A. caliginosus, is a single polypeptide-chain glycoprotein with a mol.wt of about 33,500, which contains 10.1% carbohydrate. The isoelectric point of the enzyme is 3.5 and the enzyme has 274 amino acid residues based on the mol.wt of 33,500. The enzyme hydrolyzed arginine esters more readily than lysine esters, but did not hydrolyze tyrosine ester. The activity of the enzyme on hydrolysis of arginine ester or on liberation of kinin from purified bovine high mol.wt kininogen was inhibited by diisopropylfluorophosphate, indicating that the serine hydroxyl group is involved in enzymatic activity. Moreover, the enzyme split N-alpha-carbobenzoxy-Gly-Pro-Arg-p-nitroanilide (PNA), H.D.Val-Leu-Arg-PNA, H.D.Pro-Phe-Arg-PNA, H.D.Phe-pipecolyl-Arg-PNA and Pro-Phe-Arg-4-methylcoumaryl-7-amide more readily than the other chromogenic or fluorogenic substrates. This result indicates that the substrate specificity of the enzyme is broader than that of mammalian serine proteinases.

Crotalid Venoms↗
PubMed1988

Secondary carnitine deficiency in hyperammonemic attacks of ornithine transcarbamylase deficiency.

Carnitine status was evaluated in 12 patients with hyperammonemic attacks caused by a deficiency in ornithine transcarbamylase. We found decreased free carnitine and increased acylcarnitine levels in the serum, a decreased free carnitine content and an elevated acyl/free carnitine ratio in the liver, and increased excretion of free and acylcarnitine in the urine. Analyses of urinary acylcarnitine using the secondary ion mass spectrometry technique revealed increased amounts of acetylcarnitine and dicarboxylic acid derivatives. These data suggest that the patients had a secondary carnitine deficiency, possibly an aggravating factor in urea cycle dysfunction. After oral administration of L-carnitine (50 to 100 mg/kg/d) in two patients, hyperammonemic episodes were less frequent. Blood ammonia levels decreased significantly, accompanied by an increase in serum free carnitine levels.

Ammonia↗
PubMed1988

Atypical Prader-Willi syndrome with severe developmental delay and emaciation.

A young boy showed features of Prader-Willi syndrome including hypotonia, cryptorchidism, a mildly dysmorphic facial appearance, a high-arched palate and an open triangular-shaped mouth, but had additional symptoms such as simian creases and multiple joint ankylosis in early infancy. Deletion of the long arm of chromosome 15(q11.2 to q13) was recognized. A muscle biopsy specimen showed variation in fiber size with hypertrophic type 1 fibers, type 2 fiber smallness, type 2B fiber paucity and an increased number of type 2C fibers. At the age of 4 1/2 years, he still showed severe developmental delay with severe muscle hypotonia, weakness and emaciation.

Child, Preschool↗
PubMed1988

Neonatal onset of medium-chain acyl-CoA dehydrogenase deficiency in two siblings.

Two male siblings with medium-chain acyl-CoA dehydrogenase deficiency were reported, in whom the enzyme activity was essentially undetectable and the symptoms and signs, including cyanosis, apnea, low body temperature, hypoglycemia and hyperammonemia, appeared within 48 hours of life. Muscle weakness and cardiomegaly in association with morphological abnormalities of mitochondria in skeletal and cardiac muscles, respectively, were found on electron microscopic examination in one of them. These observations suggest that the patients suffered from the most severe form of the disease, which has not been described in the literature.

Acyl-CoA Dehydrogenases↗
PubMed1988

Beneficial effects of coenzyme Q10 on impaired left ventricular performance in streptozotocin diabetic rats.

Chronic effects of coenzyme Q10 (CoQ: 30 mg/kg/day for 12 weeks) on cardiac performance in streptozotocin (45 mg/kg) induced diabetic rats were examined. Cardiac performance was assessed using the isolated retrograde perfused isovolumically contracting heart model. Compared to age matched nondiabetic rats, decreases occurred in myocardial CoQ (25.8 +/- 3.3 vs. 31.9 +/- 2.7 micrograms/ml), AMP (0.9 +/- 0.7 vs. 2.0 +/- 0.4 micrograms/mg), Emax (37 +/- 14 vs. 80 +/- 38 mmHg/microliter/g), an index of myocardial contractility, and LV diastolic chamber stiffness constant k (0.68 +/- 0.13 vs. 1.31 +/- 0.59 g/microliter) in diabetic rats. Normalized left ventricular weight (2.97 +/- 0.23 vs. 2.51 +/- 0.21 mg/g) and volume (1.53 +/- 0.34 vs. 0.89 +/- 0.53 microliter/g) and time constant of left ventricular pressure fall, T (32.0 +/- 8.0 vs. 19.7 +/- 2.6 ms) increased in diabetes. In diabetic rats taking CoQ, myocardial CoQ (28.5 +/- 3.2 micrograms/ml) and AMP (2.1 +/- 1.7 micrograms/mg) were the same as control, and T (23.5 +/- 7.4 ms) was significantly shortened (mean +/- SD, p less than 0.05, p less than 0.01). To compensate for depressed myocardial contractility and relaxation, LV dilatation and increased LV mass occurred in diabetic rats. Exogenous CoQ increased myocardial CoQ content and improved myocardial relaxation in diabetic rats.

Adenine Nucleotides↗
PubMed1988

The effects of oxygen toxicity on the pregnant rat using an apparatus designed to measure oxygen consumption method.

To evaluate the effects of oxygen toxicity in the pregnant rat at high and low concentrations of oxygen, an oxygen-consumption apparatus was devised to measure the consumption of oxygen continuously over long periods. Oxygen consumption, partial oxygen pressure on the skin (tcPo2), and lipid peroxide levels in the serum were measured. There was a close correlation between oxygen consumption and body weight of rats that weighed between 150 g and 450 g. Oxygen consumption during the later stages of pregnancy increased by 1.8 ml/day, an increase of 8%. Oxygen consumption by rats during parturition increased markedly for up to 1 h and then reached and remained at a plateau value until the end of delivery. Exposure of pregnant rats to low concentrations of oxygen resulted in a marked depression in oxygen consumption and tcPo2 during the exposure time. A significant increase in the lipid peroxide level in serum was observed in the mother rat after birth and in the newborn offspring of pregnant rats exposed to 16% oxygen for 3 h.

Animals↗
PubMed1988

[A case of primary malignant fibrous histiocytoma of the right lung].

A malignant fibrous histiocytoma (MFH) is the most common soft tissue sarcoma found in adults, but a primary MFH of the lung is very rare. A chest X-ray taken of a 73-year-old man revealed a massive lesion in the right upper lobe, and a subsequent right upper lobe lobectomy uncovered a soft, light yellow tumor in the right S3 area, measuring 2.8 x 2.6 x 1.7 cm. Histologically, the tumor manifested a typical storiform pattern of spindle-sharp cells with no sign of a myosarcoma. As no abnormal lesion was detected in the abdomen and extremities, the tumor was diagnosed as a primary MFH of the lung.

Aged↗