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Biomedical subjects

Y Ohta

Publications and source records attributed to Y Ohta.

At least 19 recordsLinked to original sources
PubMed1992

Presynaptic A1-purinoceptor-mediated inhibitory effects of adenosine and its stable analogues on the mouse hemidiaphragm preparation.

1. The effect of adenosine or its stable analogues (2-chloroadenosine, CADO; 5'-N-ethylcarboxamidoadenosine, NECA; and N6-cyclopentyladenosine, CPA) on the release of [3H]-acetylcholine ([3H]-ACh), and on the development of force of contraction evoked by electrical stimulation of the nerve, were studied in the mouse phrenic nerve-hemidiaphragm preparation. Evidence was obtained that the release of ACh is subject to presynaptic modulation through presynaptic A1(P1)-purinoceptors. 2. Adenosine or its stable analogues (CADO, NECA, CPA) inhibited, in a concentration-dependent manner, both the release of ACh and the force of the indirectly elicited contraction of hemidiaphragm preparation, provided in the latter case that the margin of safety was reduced by (+)-tubocurarine or magnesium. The order of potency in reducing ACh release was CPA greater than NECA greater than CADO greater than adenosine with IC50 values of 0.08 +/- 0.01, 0.74 +/- 0.05, 9.05 +/- 0.20, and 410.2 +/- 42.5 mumol/l, respectively. The order of potency in reducing twitch tension was CPA greater than NECA greater than CADO greater than adenosine with IC50 values of 0.11 +/- 0.02, 0.48 +/- 0.03, 2.07 +/- 0.49, and 240.4 +/- 20.0 mumol/l, respectively. 3. 8-Phenyltheophylline (8-PT) antagonized the inhibitory effects of the adenosine receptor agonists on ACh release and twitch tension.(ABSTRACT TRUNCATED AT 250 WORDS)

2-Chloroadenosine↗
PubMed1992

Estimation of IgG subclasses of anti-HCV (C100-3) in non-A, non-B fulminant, acute and chronic hepatitis and it's significance.

To determine whether identification of subclasses of anti-HCV IgG would help distinguish between acute and fulminant hepatitis, we assayed serum IgG subclasses of anti-HCV (C100-3) in non-A, non-B hepatitis. Anti-HCV IgG was restricted to two subclasses in different diagnostic conditions; anti-HCV IgG1 and anti-HCV IgG3. Anti-HCV IgG1 was the main subclass in acute hepatitis (AH), and was positive in all the cases and only one case was positive for anti-HCV IgG3. Anti-HCV IgG3 was the dominant subclass in fulminant hepatitis (FH). Out of the total 12 cases of FH, who were positive for either anti-HCV IgG or for any of it's subclasses, in 10 cases (83%), anti-HCV IgG3 had higher optical density (OD) values than anti-HCV IgG1 and in 6 cases (50%) was the only subclass of anti-HCV IgG being positive. In 5 cases with FH, anti-HCV IgG3 became positive even when anti-HCV IgG was negative. These findings from the basis of a new observation and are likely to be helpful in the diagnosis of non-A, non-B fulminant hepatitis.

Acute Disease↗
PubMed1992

Hepatocyte membrane stabilization by prostaglandins E1 and E2: favorable effects on rat liver injury.

When prostaglandin (PG) E1 was continuously administered to rats from 24 hours before giving a dose of carbon tetrachloride, deranged serum glutamic pyruvic transaminase levels and prothrombin time were significantly reduced 12 hours after intoxication compared with controls. A similar effect of PGE1 was seen at 24 hours in D-galactosamine-intoxicated rats. Liver histology showed a comparable attenuation of injury in these rats. These results were consistent with reported effects of PGE2, suggesting that both prostaglandins may share a common pathway in protection against liver injury. When PGE1 or 16,16'-dimethyl PGE2 was added to the medium of primary cultured rat hepatocytes, lipid peroxidation-dependent killing of the cells by tert-butyl hydroperoxide was significantly attenuated without affecting the extent of malondialdehyde accumulation compared with controls. Both prostaglandins significantly reduced the extent of increased plasma membrane microviscosity of these cells assessed by 1-[4-(trimethyl-ammonio)phenyl]-6-phenyl-1,3,5-hexatriene. PGE1 and PGE2 may possess cytoprotective effects on liver parenchymal cells through stabilization of membrane microviscosity, which may contribute to protection against liver injury.

16,16-Dimethylprostaglandin E2↗
PubMed1992

Analysis of responses to endothelins in isolated porcine blood vessels by using a novel endothelin antagonist, BQ-153.

We examined the effects of a novel ETA-selective endothelin (ET) antagonist, BQ-153, on vascular responses to ET-1 and ET-3 in isolated porcine coronary and pulmonary blood vessels, to clarify the roles of ET receptor subtypes in the regulation of vascular smooth muscle tension. With endothelium-denuded vascular tissues, the concentration-contraction curve (CCC) for ET-1 appeared as a single sigmoidal shape for all types of tissue. The CCC for ET-1 was antagonized by BQ-153 (2 and 10 microM) in all tissues, but part of the contraction was resistant. The CCC for ET-3 usually consisted of two different phases with higher (first phase) and lower (second phase) sensitivities to the peptide. Only the second phase of CCC for ET-3 was completely inhibited by BQ-153 (2 microM) in all tissues, while the first phase was resistant. The BQ-153-resistant contractile phases of ET-1 and ET-3-induced vasoconstriction appeared to have similar sensitivity in all tissues, and the contractile activity varied with each type of tissue. With endothelium-intact materials, the potencies of ET-1 and ET-3 for endothelium-dependent vasorelaxation in pulmonary artery were almost equivalent. BQ-153 (10 microM) did not inhibit ET-induced vasorelaxation. These results indicate that ET-induced vasoconstriction is mediated not only through ETA but also through ETnonA (probably ETB), and that the relative proportions of the ET-receptor subtypes mediating contractions vary in different vascular areas. In addition, results showed that ET-induced endothelium-dependent vasorelaxation is mediated through ETB.

Animals↗
PubMed1992

Experience of a small PACS in Tottori University Hospital.

Picture archiving and communications systems (PACS) are expected to become feasible as the way of total radiologic image management. As the first step towards computerized image management, we installed an experimental small PACS with a digital optical archive for magnetic resonance and digitized radiographic film images. During the first 10 months of operation, problems were caused by the frequent mechanical troubles on the acquisition devices, impractical schemes for transmission, and troublesome retrieval and display of images. Although some of them have been solved by the improvements of both hardware and software, the mechanical instability of the digitizer and the inadequate operating procedure of the workstation still remain. As to the characteristics of PACS, the capability of access to every achieved radiologic image is the great advantage for us because the image integration has been impossible in the form of radiographic films for the traditional image management system of our hospital. However, the complicated image display procedure with high overheads is far from ideal for radiologists. The efficiency of image display must be increased to the level of a conventional film viewing system. Furthermore, research is needed on the small PACS to get consensus for the acceptance of a more widely implemented system.

Computer Systems↗
PubMed1992

Lichen planus annularis: an immunohistochemical study.

Lichen planus annularis is a relatively rare skin manifestation of lichen planus. The mechanisms in the formation of annular lesions are not fully understood. We reported here a 57-year-old female with this disease. The eruption initially occurred as lichen-papules, then enlarged (bean-sized, umbilicated small plaques), and finally developed annular manifestations. We performed immunohistochemical examinations of specimens taken from different types of eruptions. In all specimens, HLA-DR was expressed in the focal keratinocytes adjacent to the dermal HLA-DR positive cell infiltration. Both in the initial papule and in the final annular lesion, expression of ICAM-1 was present only in the keratinocytes above the dermal cell infiltration, similar to HLA-DR. It is of interest that, in the umbilicated small plaques, the peripheral epidermis other than the central site extensively reacted to ICAM-1. LFA-1 expression was most prominent in the mononuclear cells impinging on the dermo-epidermal junction in all specimens. In addition, in the periphery of the umbilicated small plaques, which showed no bandlike dense cell infiltration nor degeneration of basement membrane, TNF-alpha, but not LFA-1, was positive in the infiltrated cells of the upper dermis. These results suggest that expressions of ICAM-1 and TNF-alpha in the peripheral keratinocytes and dermal infiltrated cells are important molecular events in the mechanisms of formation of the annular lesions.

Antigens, CD↗
PubMed1992

Myelin gangliosides of human peripheral nervous system: an enrichment of GM1 in the motor nerve myelin isolated from cauda equina.

Myelins of the PNS were isolated from human motor and sensory nerves of cauda equina, and their ganglioside compositions were compared. The predominant ganglioside in the human PNS myelins, both from motor and sensory nerves, was LM1 (sialosylneolactotetraosylceramide). Sialosyl-nLc6Cer and disialosyl-nLc4Cer, GD3, GM3, and GD1b were detected as common components of the two nerve myelins. Furthermore, it was revealed that the motor nerve myelin contained GM1 (about 15% of total gangliosides), whereas sensory nerve myelin contained only a trace amount of GM1 (less than 5%), by TLC analyses together with TLC immunostaining using anti-GM1 antibody. As for the disialoganglioside fraction, the content of GD1a, as well as that of GM1, differed in motor and sensory nerves. Thus, the different contents of the ganglioseries gangliosides in human motor and sensory nerve myelins were demonstrated.

Cauda Equina↗
PubMed1992

Binding of mutagenic pyrolyzates to fractions of intestinal bacterial cells.

The binding of mutagenic pyrolyzates to cell fractions from some gram-negative intestinal bacteria and to thermally treated bacterial cells was investigated. 3-Amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1) and 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2) were effectively bound by several of the bacterial cells. The cell wall skeletons of all bacteria effectively bound Trp-P-1 and Trp-P-2. Their cytoplasmic fractions retained Trp-P-1 and Trp-P-2, but to a lesser extent than the cell wall skeletons. 2-Amino-3-methylimidazo[4,5-f]quinoline (IQ) was not found in their cytoplasmic fractions. These cell wall skeletons also bound 2-amino-6-methyldipyrido[1,2-a:3',2'-d]imidazole (Glu-P-1), 2-amino-5-phenylpyridine (Phe-P-1), IQ, 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ), and 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQX). The amount of each mutagen bound differed with the type of mutagen and the bacterial strain used. The outer membrane of Escherichia coli IFO 14249 showed binding of about 123.7 micrograms/mg of Trp-P-2, and its cytoplasmic membrane bound 57.14 micrograms/mg. Trp-P-2 bound to the bacterial cells was extracted with ammonia (5%), methanol, and ethanol but not with water.

Bacteroides fragilis↗
PubMed1992

31P-NMR study of skeletal muscle metabolism in patients with chronic respiratory impairment.

To evaluate the energy metabolism of peripheral skeletal muscle during exercise in patients with chronic respiratory impairment, the 31P-nuclear magnetic resonance (NMR) spectra of forearm muscle were investigated in nine patients and nine age-matched control subjects. We calculated the phosphocreatine (PCr) to PCr + inorganic phosphate (PI) ratio, the time constant of PCr recovery and the intracellular pH. The exercise consisted of repetitive hand grips against a 2-kg load every 3 s for 6 min (0.33 W). The patients showed a marked decrease in the PCr/(PCr + PI) ratio and pH in the muscle during exercise in contrast to the control subjects whose PCr/(PCr + PI) showed a minor decrease without any change in pH. The relationship between PCr utilization and pH demonstrated that anaerobic glycolysis switched on earlier in patients with chronic respiratory impairment. A split PI peak was observed in five of nine patients during exercise. The PCr/(PCr + PI) ratio during the last minute of exercise correlated significantly with the vital capacity (% predicted), with the FEV1/FVC, with the body weight, with the maximum strength of hand grip, and with the muscle mass. The results indicate impaired oxidative phosphorylation and the early activation of anaerobic glycolysis in the muscles of patients with chronic respiratory impairment. Several factors related to chronic respiratory impairment, such as disuse, malnutrition and dysoxia, would contribute to the metabolic changes observed in the muscles examined.

Aged↗
PubMed1992

Reperfusion after a two-hour period of pulmonary artery occlusion causes pulmonary necrosis.

The role of reperfusion injury in the progression to necrosis in pulmonary embolism was evaluated. To simulate this condition, we used a technique that enables occlusion and reopening of the pulmonary arterial branch supplying the right upper lobe in conscious rats. The rats were divided into five groups: the occlusion group (n = 12), in which the pulmonary artery (PA) branch was occluded without reperfusion; the reperfusion group (n = 12), in which the PA branch was reopened after a 2-h period of occlusion; and the reperfusion-SOD (n = 9), reperfusion-IM (n = 8), or reperfusion-IA-SOD (n = 6) groups, in which superoxide dismutase (SOD), indomethacin (IM), or inactivated SOD (IA-SOD), respectively, was administered during reperfusion. The lungs were removed 24 h after the PA occlusion, and histologic examination was performed. In the occlusion group, the alveolar structure of the right upper lobe was well preserved, and there was no erythrocyte or leukocyte accumulation. The only significant changes compared with the control lobe was the appearance of wavy internal elastic lamina of the PA and slight neutrophil adherence to the endothelial cells. In contrast, the right upper lobe of the reperfusion group disclosed numerous foci of hemorrhagic necrosis, with disrupted alveoli and leukocyte accumulation in all cases. With SOD treatment, the changes compatible with hemorrhagic necrosis were attenuated to the level of the control lobes. However, neither IM nor IA-SOD decreased these changes.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Continuous chitosan hydrolyzate production by immobilized chitosanolytic enzyme from Enterobacter sp. G-1.

Chitosanolytic enzymes from Enterobacter sp. G-1 were immobilized on various carriers to continuously hydrolyze chitosan. Four different carriers were tested: FE-3901 (strong basic anion exchange resin, ionic binding), glutaraldehyde-treated FE-4612 (weak basic anion exchange resin, cross-linking), Chitopearl (chitosan beads), and alginate calcium. Glutaraldehyde-treated FE-4612 and Chitopearl immobilized more protein than the others. The enzyme immobilized on FE-3901 had the greatest activity. The activity of enzyme immobilized on FE-3901 decreased rapidly when exposed to a continuous flow of 1% chitosan. The enzyme immobilized with Chitopearl retained more than 50% of its original activity after 17 days, and the activity was fully restored by re-immobilization.

Anion Exchange Resins↗
PubMed1992

Expiratory activity of the inspiratory muscles during cough.

To investigate the neural mechanism of the expiratory activity of the inspiratory muscles during a cough, EMG of the respiratory muscles were recorded in anesthetized and tracheostomized dogs. A laparoscope was used to minimize injury to the abdominal muscles for implantation of the electrodes into the costal diaphragm. During the expulsive phase of a cough, the diaphragm was active in 7 of 12 dogs and the external intercostal muscle was active in 3 of 6 dogs. During a cough, the expiratory activity of the diaphragm, after the termination of its inspiratory activity, started at 52.9 +/- 24.6 ms, and that of external intercostal muscle started at 51.1 +/- 20.5 ms. The expiratory activity of the internal intercostal muscle and of the transversus abdominis started at 34.3 +/- 13.0 and 27.8 +/- 15.2 ms, respectively. The onset of expiratory activity of the inspiratory muscles is significantly later than that of expiratory muscles. Continuous activity in the expiratory muscles evoked by airway occlusion, i.e., Hering-Breuer reflex, was suppressed during the inspiratory phase of a cough, but not suppressed during the expulsive phase even when the expiratory activity of the diaphragm was observed. We concluded that the expiratory activity of inspiratory muscles is controlled independently of both expiratory activity of the expiratory muscles and inspiratory activity of the inspiratory muscles.

Animals↗
PubMed1992

Machine perfusion of isolated kidney at 37 degrees C using pyridoxalated hemoglobin-polyoxyethylene (PHP) solution, UW solution and its combination.

To preserve isolated kidney normothermically, PHP containing UW components were evaluated as perfusates. Kidneys were flushed out by Lactate Ringer solution immediately after isolation from mongrel dogs, and then connected to the perfusion circuit which consists of a preservation box, a reservoir of perfusate, a membrane oxygenator and a drive unit. PHP containing 140 mEq/l of Na+ and 4 mEq/l of K+ (PHP(E)), UW solution (UW) and UW components added PHP(E) were prepared and adjusted at pH 7.4 prior to use. Temperature and perfusion pressure were controlled at 37 degrees C and 100 mmHg, respectively. During 12 hour perfusion, remarkable changes in pH were seen in UW group and PHP group while higher oxygen consumption was noted in PHP(E)+UW group than that in PHP(E) group. The histological findings showed moderate damages of tubular epithelial cells and maintaining normal glomerular structure in PHP(E)+UW while severe damage of both tubulus in UW group were seen. There was no edematous degeneration in both UW and PHP(E)+UW groups, however, it was seen in PHP(E) alone. It was suggested that components of UW solution have positive effect on normothermic machine perfusion with PHP(E) solution.

Adenosine↗
PubMed1992

Performance of an enzyme-linked immunosorbent assay system for antibodies to hepatitis C virus with two new antigens (c11/c7).

We developed an enzyme-linked immunosorbent assay (ELISA) system for antibodies to the hepatitis C virus (HCV), using two new recombinant antigens (c11 and c7) derived from the HCV genome. The performance of this ELISA system (Imucheck HCV Ab) was examined. The CV values for both intra-assay precision and reproducibility of identifying HCV antibody in the panel sera ranged from 3.5% to 6.4%. The blood elements in serum and anticoagulants did not interfere in this ELISA system. The specificity of Imucheck HCV Ab to samples from patients with non-A, non-B (NANB)-type chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma was 93.7%, 93.5%, and 81.4%, respectively. These results are more sensitive than those obtained by the first-generation anti-HCV ELISA system. In the samples from patients with NANB-type acute hepatitis, Imucheck HCV Ab enabled detection of HCV antibodies at an early stage. This system increased the sensitivity for blood donor screening and for monitoring patients with acute hepatitis.

Antibody Specificity↗
PubMed1992

[A case of steroid psychosis associated with betamethasone].

Psychotic side effects of steroids have been observed at relatively high frequency if mild cases, such as euphoria, are included, while it has been said that incidences differ among kinds of steroids. We reported a case developing severe schizophrenia-like symptoms following the treatment with betamethasone although this drug is believed to be rarely involved in steroid-induced psychosis, and its psychotic side effects have been rarely reported. When betamethasone was administered for progressive peripheral facial paralysis at a mean daily dose of 7mg, psychotic symptoms appeared from the 15th treatment day. Psychosis began with interrupted appearance of excitation, autism, and misanthropia. Although the steroid was gradually decreased in dose because of abatement of facial paralysis, not only psychotic symptoms were aggravated, but also appeared hallucination. Thus the steroid was withdrawn before the scheduled date while its dose was gradually decreased, and haloperidol was administered. Psychotic symptoms were gradually eliminated and completely disappeared about 40 days after onset.

Adult↗
PubMed1992

[Repeated arterial infusion chemotherapy for inoperable hepatocellular carcinoma using implantable drug delivery system].

We performed a clinical evaluation of repeated arterial infusion chemotherapy using an implantable drug delivery system for 41 patients with inoperable hepatocellular carcinoma (HCC). About half of our patients could not undergo transcatheter arterial embolization (TAE) because of extreme tumor extension and/or accompanying advanced cirrhosis. In most patients we implanted a 5 Fr. catheter non-surgically and connected it to an implanted injection port through a subcutaneous tunnel. The treatment schedule was weekly or biweekly intrahepatic one-shot administration of mitomycin C, adriamycin, 5-fluorouracil and epirubicin. The response rate (CR + PR) was 24.4%. The median survival period was 401.1 days. The 6 month, 1-year and 2-year survival rates were 73%, 48% and 24%, respectively. There were no severe side effects nor complications. The implantable drug delivery system will contribute not only to improved therapeutic efficacy for inoperable HCC but also improve the quality of life for patients.

Adult↗
PubMed1992

Anti-hepatitis C virus immunoglobulin M antibody in patients with chronic hepatitis type C.

Anti-hepatitis C virus immunoglobulin M antibody titers were measured by enzyme-linked immunosorbent assay in 28 patients with chronic hepatitis C. Nine patients were treated with alpha-interferon at a dosage of 3 MIU/day for 4 weeks. Anti-HCV IgM was positive in 12 of the 28 patients, and these 12 patients also had significantly higher anti-HCV antibody titers than those patients who were negative for anti-HCV IgM. Among the 9 patients treated with alpha-interferon, anti-HCV IgM positivity was significantly lower in 4 good responders than in 2 non-responders and 3 transient responders at 12 months after the completion of treatment (p < 0.01). These results suggest that anti-HCV IgM titers might be useful for monitoring the antiviral effect of interferon treatment in CH C.

Adult↗