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Biomedical subjects

Y Ohta

Publications and source records attributed to Y Ohta.

At least 667 records · Page 37Linked to original sources
PubMed1991

Efficient cloning of hepatitis B virus DNA from single-stranded replicative intermediates and its application to S1 mapping of viral RNA in human liver tissue.

An efficient method for cloning subgenomic fragments of the hepatitis B virus (HBV) was developed, utilizing its abundant single-stranded replicative intermediates. The total genomic DNA obtained from the liver tissue of patients with chronic HBV infection was treated by using the Klenow fragment of E. coli DNA polymerase I without adding any exogenous primers. Single-stranded replicative intermediates were efficiently converted to double-stranded linear DNA, one end of which terminated at (or near to) the direct repeat 1 (DR1) sequence of the HBV genome. By screening less than 1,000 recombinants from a DNA library after this treatment, we obtained a subgenomic HBV fragment of 2.0 kilobases. We then analysed HBV RNA in human liver tissue by S1 mapping. It was possible to map HBV RNA only when a DNA probe from the same tissue was used.

Cloning, Molecular↗
PubMed1991

Clinical significance of the measurement of hepatic blood flow using xenon 133 and balloon catheter in patients undergoing treatment for hepatocellular carcinoma.

Total hepatic blood flow and portal blood flow were measured separately using a modified xenon 133 clearance method during angiography in 71 patients with chronic liver diseases, including 40 with proven hepatocellular carcinoma, and in 12 patients without detectable chronic liver injury who served as controls. Total hepatic and portal blood flow rates in controls were 805 +/- 149 ml/min and 667 +/- 206 ml/min, respectively. Total hepatic blood flow was significantly decreased in patients with compensated and decompensated liver cirrhosis (519 +/- 156 ml/min and 317 +/- 153 ml/min, respectively; P less than 0.01), as was portal blood flow (399 +/- 134 ml/min and 271 +/- 134 ml/min, respectively; P less than 0.01). Following transcatheter arterial embolization or hepatic resection (in 35 and 13 patients, respectively), hepatic failure occurred in 3 cases each. Embolization appeared contraindicated when hepatic portal blood flow was under 125 ml/min, and safe hepatic resection required an anticipated residual hepatic portal blood flow of at least 250 ml/min.

Carcinoma, Hepatocellular↗
PubMed1991

In situ expression of messenger RNA of interleukin-1 and interleukin-6 in psoriasis: interleukin-6 involved in formation of psoriatic lesions.

Psoriasis is a disease of abnormal proliferation and differentiation of epidermal cells. Several cytokines released by keratinocytes are implicated as factors responsible for this pathological condition of the epidermis. In order to elucidate the role of these cytokines in psoriasis, messenger RNA (mRNA) expression of interleukin-1 (IL-1) and IL-6 in psoriatic epidermis was investigated using biotin-labelled complementary DNA (cDNA) of the cytokines. Messenger RNA of IL-1 alpha was weakly detected in some normal healthy epidermis specimens and more strongly in all the perilesional uninvolved psoriatic epidermis specimens. It was also expressed in the transitional zone between uninvolved and fully developed psoriatic skin, but was not expressed in lesional skin. In contrast, IL-6 mRNA was rarely expressed in normal healthy epidermis, but was expressed in perilesional uninvolved psoriatic epidermis, in the transitional zone and in the fully developed lesional epidermis, with the maximum intensity in the transitional zone. Expression of mRNA of IL-6 receptor showed a similar tendency to that of IL-6. It was expressed in psoriatic epidermis, most strongly in the transitional zone, but not in normal healthy epidermis. IL-6 was demonstrated immunohistochemically in psoriatic epidermis, but IL-6 receptor was demonstrated only in the transitional zone. Thus IL-6 and its receptor expression correlated well with the formation of psoriatic lesions where IL-1 may initiate their expression. IL-6 may play an important role in the pathogenesis of psoriasis.

Adult↗
PubMed1991

Insulin and glucagon therapy of acute hepatic failure.

When insulin and glucagon are administered to rats with severe liver injury, survival is enhanced with an attenuation of the liver injury compared to that of untreated controls. In rats with acute liver injury both hormones produce a rapid normalization of hepatic protein content following initiation of DNA synthesis. When rats receive both hormones after partial hepatectomy, the first burst of DNA synthesis reaches a maximum earlier than that seen in controls. Both hormones enhance the increment of hepatic putrescine essential for DNA synthesis through activation of ornithine decaroxylase and/or spermidine-N1-acetyltransferase. The enhancement of putrescine content by each hormone is additive. Putrescine supplementation promotes hepatic DNA synthesis after hepatectomy. Based on these data, we conclude that a combination of insulin and glucagon is effective in the therapy of acute hepatic failure in rats. The restoration of liver function as well as the stimulation of liver cell proliferation via putrescine production may contribute to this effect.

Acetyltransferases↗
PubMed1991

Voltage-gated K+ channels in the mouse interleukin 3-dependent cell line, FDC-P2.

The electrical properties of a mouse interleukin (IL)-3-dependent cell line, FDC-P2, were examined using the tight-seal whole-cell clamp technique. Under current clamp conditions with 140 mM K+ in the pipette, the cells had a resting potential of approximately -30 mV. Under voltage-clamp conditions, a transient outward current was elicited upon depolarization from a holding potential of -80 mV. The current was activated at potentials more positive than -10 mV and had a delayed-rectifying property. It showed rapid activation and slow inactivation during command steps. The current was abolished by Cs+ in the pipette, indicating that K+ is the charge carrier. The K+ current was suppressed by tetraethylammonium with Ki of less than 0.1 mM and was not affected by scorpion toxin. Recovery from inactivation was steeply voltage dependent: As the holding potential was more hyperpolarized, the recovery became faster. Thus, with a holding potential of -80 mV, the current showed slight use-dependent inactivation, while the current decreased prominently by repetitive depolarization at a holding potential of -40 mV. These properties of the K+ current are similar to those of the l-type K+ channel current in mature T lymphocytes. The K+ current in FDC-P2 cells was dramatically reduced after culture in the IL-3-free medium for 1-2 days. When IL-3 was re-added to the medium, the current was re-expressed. These observations suggest that expression of the K+ current depends on extracellular IL-3, and that the current may play some roles in proliferation of these cells.

Animals↗
PubMed1991

Intrafamilial transmission of hepatitis C virus in Japan.

To study the intrafamilial transmission of hepatitis C virus (HCV), 36 family members of 16 patients with anti-HCV (anti-C100-3)-positive chronic liver disease were screened for anti-HCV by an enzyme-linked immunosorbent assay (ELISA). Clusters of anti-HCV-positive individuals were observed in 2 of 16 families (12.5%). Four of 35 family members (11.4%) with no history of blood transfusion were positive for anti-HCV. Two of 17 offspring (11.8%) of anti-HCV-positive females were positive for anti-HCV, while 1 of 5 spouses (20.0%) was positive for anti-HCV. These data suggest that intrafamilial transmission is one of the possible routes of infection for HCV.

Adult↗
PubMed1991

Detection of hepatitis C virus antibody in patients with autoimmune hepatitis and other chronic liver diseases.

To clarify the relationship between autoimmune hepatitis (AIH) and the hepatitis C virus (HCV), we investigated the prevalence of antibodies to HCV (anti-HCV) by an enzyme-linked immunosorbent assay in patients with AIH, primary biliary cirrhosis (PBC), rheumatoid arthritis and multiple myeloma. The antibody was detected in 9 out of 18 patients with AIH (50%), in 3 out of 23 with PBC (23%), in 2 out of 10 with rheumatoid arthritis (20%), and in 5 out of 9 with multiple myeloma (56%). However, the optical density values in these patients were lower than those observed in non-A, non-B hepatitis (NANBH). Anti-HCV became negative immediately after the initiation of glucocorticoid therapy in all four antibody-positive AIH patients tested. The extracted immunoglobulin G fraction from sera of 5 anti-HCV negative AIH patients became positive for the antibody. This phenomenon was not observed in 5 normal volunteer sera. The 9 family members of three anti-HCV positive AIH patients showed no anti-HCV positivity. These results suggest that autoantibodies in AIH patients may cross-react with the HCV-related antigen. Direct association of the HCV influencing the development of AIH is unlikely. Therefore, care should be taken in the evaluation of anti-HCV positivity in patients with autoimmune diseases and multiple myeloma.

Aged↗
PubMed1991

The pre- and postjunctional components of the neuromuscular effect of antibiotics.

The relative contributions of the pre- and postsynaptic components of the myoneural blocking effect of different antibiotics were studied using: (a) a radio-active method that measures selectively the Ca(2+)-dependent, stimulation evoked, quantally released, (3)H-acetylcholine ((3)H-ACh) from the mouse in vitro phrenic nerve-hemidiaphragm preparation without cholinesterase inhibition; (b) measurement of the force of contraction of the indirectly or directly stimulated muscle. The antibiotics studied (neomycin, polymyxin B and lincomycin), reduced the release of (3)H-ACh evoked by stimulation (18 trains of 40 shocks at 50 Hz) in a concentration dependent manner. While the inhibitory effect of neomycin was inversely related to [Ca(2+)](o), that of lincomycin was moderately and that of polymyxin B was not affected by increasing [Ca(2+)](o) from 0.75 to 5.0 mM. Similarly, the d-tubocurarine (d-Tc)-induced inhibition of the release of (3)H-ACh was independent of [Ca(2+)](o). The K-channel blocking agent, 4-aminopyridine (4-AP), enhanced the release of ACh in a concentration dependent manner and prevented the neuromuscular effect of neomycin. However, the neuromuscular effect of polymyxin B and of lincomycin was not affected by 4-AP. Atropine, enhanced the release of (3)H-ACh. Antibiotics, however, were still able to reduce the release of ACh when the negative muscarinic feedback mechanism of ACh release was eliminated by atropine. Our findings indicate that the antibiotics studied possess both pre- and postsynaptic effects. Presynaptically they reduce the evoked release of ACh; postsynaptically they inhibit muscle contractility. The rank order of presynaptic action is neomycin >polymyxin B >lincomycin.

Journal Article↗
PubMed1991

Characterization of the L-tryptophan transport system in the liver of growing rats.

In order to characterize the system of L-tryptophan (TRP) transport into liver during the growing period of 10 to 42 days, the changes of tryptophan 2,3-dioxygenase (TDO) activity, levels of serum, liver, brain, and muscle TRP, and the rate and mode of TRP uptake into isolated hepatocytes were examined in male Wistar rats. Liver TDO activity increased rapidly at 16 days of age. A marked and rapid decrease in free serum TRP level occurred before weanling, while a small decrease in total serum TRP level was found after weanling. The change of liver TRP level was similar to that of free serum TRP level and correlated well. There was a significant inverse correlation between liver TDO activity and either free serum TRP level or liver TRP level. A rapid change in TRP level did not occur in brain and muscle during the growing period. The concentrations of brain and muscle TRP correlated better with those of total serum TRP than with those of free serum TRP. The rate of TRP uptake into hepatocytes isolated from rats aged 10 days was lower than that from rats aged 21 and 42 days. The former hepatocytes were lacking in a high-affinity saturable transport component for TRP uptake which was present in the latter ones. The present results indicate that a great change in the system of TRP transport into liver occurs in growing rats, and that in suckling rats a high level of free serum TRP contributes to the efficient transport of the amino acid into the liver.

Animals↗
PubMed1991

Induction of the interleukin-2 receptor (p55) by interferons.

The effect of human interferon (IFN) on the interleukin-2 receptor (IL-2R, p55) expression by peripheral blood mononuclear cells was investigated both in vitro and in vivo. IL-2R induction was assessed by the soluble IL-2R level in vitro and in vivo, which was measured by ELISA using two monoclonal antibodies to IL-2R(p55). Serum levels of sIL-2R increased significantly during IFN-alpha or IFN-beta therapy in 13 patients with chronic hepatitis B. When mononuclear cells were cultured with IFNs-alpha, -beta, or -gamma, the sIL-2R levels in the supernatant increased significantly. Dual flow cytometric analysis demonstrated that IL-2R was expressed on CD4+ and CD20+ mononuclear cells treated with IFN-alpha in vitro. CD4+ T cells and B cells may release sIL-2R when these cells are stimulated with IFN-alpha. RNA isolated from mononuclear cells treated with IFN-alpha contained increased levels of IL-2R-specific mRNA, as indicated by Northern blot analysis using an IL-2R-specific mRNA probe. These findings help to indicate how IFN plays a role in the regulation of the immune response, because IL-2R induction is known to be associated with lymphocyte activation.

CD4-Positive T-Lymphocytes↗
PubMed1991

Protein rotation study of cytochrome P-450 in submitochondrial particles: effect of KCl and intermolecular interactions with redox partners.

The rotational diffusion of cytochrome P-450 in submitochondrial particles (SMP) of bovine adrenocortical mitochondria was measured by detecting the decay of absorption anisotropy, r(t), after photolysis of the heme.CO complex by a vertically polarized laser flash. Analysis of r(t) was based on a "rotation-about-membrane normal" model. The measurements were used to investigate the effect of KCl on intermolecular interactions involving cytochrome P-450 and to investigate the interactions of cytochrome P-450 with other redox partners. The rotational diffusion of cytochrome P-450 was significantly dependent on KCl concentration. When the KCl concentration was increased from 0 to 1,000 mM, the mobile population of cytochrome P-450 was increased from 33 to 82%. After removing the KCl, the mobile population of cytochrome P-450 returned to the original 33%. These results suggest that nonspecific protein aggregates are dissociated by the presence of KCl, possibly due to the change in electrostatic interactions, resulting in mobilization of cytochrome P-450. SMP were observed to be nearly free from adrenodoxin and adrenodoxin reductase. The addition of adrenodoxin to SMP increased the mobile population of cytochrome P-450 from 35 to 54%. Further addition of adrenodoxin reductase to SMP containing adrenodoxin immobilized cytochrome P-450 by 6%. The addition of only adrenodoxin reductase to SMP, however, did not immobilize cytochrome P-450. The present results are consistent with our previous observations [Ohta, Y., Mitani, F., Ishimura, Y., Yanagibashi, K., Kawamura, M., & Kawato, S. (1990) J. Biochem. 107, 97-104] that cholesterol-bearing P-450SCC forms a transient ternary association with adrenodoxin and adrenodoxin reductase.

Adrenal Cortex↗
PubMed1991

The neuromuscular effects of ORG9426 in patients receiving balanced anesthesia.

In searching for a nondepolarizing muscle relaxant with intermediate duration but more rapid onset of action than the presently available compounds, the neuromuscular and circulatory effects of ORG9426 were investigated in two studies in humans receiving fentanyl, droperidol, thiopental, and nitrous oxide-oxygen anesthesia. Eighty patients, randomly assigned to one of four groups of 20 each, received 0.12, 0.16, 0.20, or 0.24 mg/kg ORG9426. In the first study, the doses (in milligrams per kilogram) of ORG9426 that caused 50% (ED50), 90% (ED90), or 95% (ED95) neuromuscular block were determined by the individual dose-response method; they were 0.170, 0.268, and 0.305 mg/kg, respectively. In the second study, after induction of anesthesia, patients received 0.6 mg/kg (about 2 x ED95) of ORG9426, either in a single bolus (group 1) or in two unequal (0.1 and 0.5 mg/kg) increments 4 min apart (group 2). After the administration of 0.6 mg/kg ORG9426, maximal neuromuscular block developed in 1.5 +/- 0.12 min in group 1 and in 1.2 +/- 0.14 min in group 2. Patients tracheas were intubated after development of the maximal neuromuscular effect of the intubating dose and after the recording of heart rate and systolic and diastolic blood pressure. There was no difference in the clinical duration of the intubating doses, which were 40.0 +/- 3.2 (15-73) min in group 1 and 39.3 +/- 2.4 (19-57) min in group 2.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗