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Biomedical subjects

K Koike

Publications and source records attributed to K Koike.

At least 649 records · Page 36Linked to original sources
PubMed1988

Effect of indomethacin, aspirin, and acetaminophen on in vitro antiviral and antiproliferative activities of recombinant human interferon-alpha 2a.

The effects of indomethacin, aspirin, and acetaminophen on the antiviral and antiproliferative activities of recombinant human interferon-alpha 2a (rIFN-alpha 2a) were studied in vitro. None of the drugs inhibited the antiviral activity of rIFN-alpha 2a in human amnion FL cells against vesicular stomatitis virus, or interfered with its antiproliferative activity against acute lymphoblastic leukemia MOLT-4 cells or renal cell carcinoma NC 65 cells. Although, at high concentrations, aspirin (1 mM) or indomethacin (0.1 mM) alone inhibited the cell growth, rIFN-alpha 2a showed clear additive growth inhibition. It was concluded that neither indomethacin, aspirin, nor acetaminophen directly inhibited the antiviral and antiproliferative activities of rIFN-alpha 2a. The possible use of these three drugs to reduce the adverse effects of rIFN-alpha 2a without spoiling its profitable efficacy in clinical practice is suggested.

Acetaminophen↗
PubMed1988

Suppression of HBsAg production in PLC/PRF/5 human hepatoma cell line by interferons.

Recombinant human interferon alpha 2a as well as natural human interferons alpha and beta significantly suppressed the production of hepatitis B surface antigen by PLC/PRF/5 cells (which have been established from a human primary hepatocellular carcinoma and proven to carry the hepatitis B virus DNA) and inhibited proliferation of these cells in vitro. However, the production of alpha-fetoprotein by PLC/PRF/5 cells was less significantly affected by any of the interferons. These results suggest that these interferons not only suppress cellular proliferation but also selectively inhibit the action of the HBV gene which is persistently present in these cells.

Carcinoma, Hepatocellular↗
PubMed1988

Human parvovirus B19-induced transient pancytopenia in a child with hereditary spherocytosis.

We report a child with hereditary spherocytosis who developed human parvovirus B19 (HPV B19)-induced transient pancytopenia. Symptoms of acute-phase illness subsided promptly after infusion of gammaglobulin containing HPV B19 antibody. The HPV B19-containing serum on admission inhibited not only erythroid colony growth but also myeloid and megakaryocyte colony growths. The inhibitory effect was abrogated by convalescent-phase serum or gammaglobulin solution containing HPV B19 antibody. These findings suggest that HPV B19-induced inhibition of haematopoiesis may be pathogenetic for transient bone marrow failure of the patient. The passive immunization may be effective in shortening the duration of acute-phase illness of HPV B19 infection.

Antibodies, Viral↗
PubMed1988

Integrated structures of duck hepatitis B virus DNA in hepatocellular carcinoma.

The structure of integrated viral DNA in a hepatocellular carcinoma of a duck from Chi-tung county in China was analyzed. Three different clones of integrated viral DNA, lambda DHS 6-1, lambda DHS 6-2, and lambda DHE 6-2, were obtained from the neoplastic portion of the liver by molecular cloning. One of the three clones, lambda DHS 6-1, showed inverted repetition of integrated viral DNA with chromosomal flanking sequences. Another clone, lambda DHS 6-2, showed a head-to-head configuration of the core and surface gene regions of duck hepatitis B virus (DHBV) DNA. The virus-chromosome junctions were often located near direct repeat 1 or 2 of DHBV DNA in three independent clones. Nucleotide sequences at the virus-virus junctions in two clones, lambda DHS 6-1 and 6-2, indicated the possible rearrangement of chromosomal DNA and recombination of viral DNA. DHBV DNA appears to be integrated into the genome of hepatocytes in a manner similar to that of human and woodchuck hepatitis viruses. Thus, the duck system may serve as a useful animal model for the study of human hepatocarcinogenesis.

Animals↗
PubMed1988

Duck hepatitis B virus (DHBV) particles produced by transient expression of DHBV DNA in a human hepatoma cell line are infectious in vitro.

Transfection of the human hepatocellular carcinoma cell line HuH7 with a plasmid containing a tandem copy of the duck hepatitis B virus DNA sequence resulted in transient replication of the virus. Viral particles secreted by transfected HuH7 cells exhibited physical properties similar to those of serum-derived duck hepatitis B virus and were infectious in primary duck hepatocyte cultures.

Animals↗
PubMed1988

Binding of [3H]befunolol to beta-adrenoceptors in cardiac muscles of fetal and neonatal rat.

Characterization of beta-adrenoceptors was studied in heart muscles of rat fetus and neonate. The results of binding assay with [3H]befunolol, a beta-adrenergic partial agonist, to membrane fractions from rat heart muscles indicate that beta-adrenoceptors contain two different affinity sites. In the presence of 5'-guanylylimidodiphosphate, the low affinity site was reduced, while the high affinity site was not affected. The dissociation constants for both sites did not change during pre- and post-natal development. But the maximum binding sites for both sites decreased slightly but significantly (p less than 0.05) during development. A 10-fold decrease in norepinephrine sensitivity and isoprenaline sensitivity during pre- and post-natal development was not explained by the slight decrease in the maximum binding sites.

Adrenergic beta-Antagonists↗
PubMed1988

Effect of vagus nerve cooling on hypercapnic and hypoxic ventilatory responses in anesthetized dogs.

We studied ventilatory responses under hypercapnic and hypoxic conditions in 18 lightly anesthetized dogs, using a vagus nerve cooling technique. One side of the cervical vagosympathetic trunks of dogs were previously severed, and a copper cooling probe was attached to the other side. When the cervical nerve was cooled below 7 degrees C, Hering-Breuer inflation reflex ceased. We found that when the vagus nerve was not cooled or cooled up to 7 degrees C, the respiratory frequency increased significantly in relation to hypercapnic gas inhalation. However, the increment of respiratory frequency was reduced by bilateral cervical vagotomy. On the other hand, the respiratory frequency in response to hypoxia increased significantly, even when bilateral vagotomy was done. The increment of the tidal volume in response to hypercapnic gas inhalation was reduced by the Hering-Breuer inflation reflex. We found that the effect of the vagus nerve on respiratory regulation was different between hypercapnic and hypoxic gas inhalation.

Animals↗
PubMed1988

Effects of cooling on alpha-1-adrenoceptor mechanisms in rat aorta.

1. The effects of cooling from 37 degrees C to 25 degrees C on alpha-1-adrenoceptor mechanisms in isolated rat aortic strips were studied. 2. The dissociation constant and the maximum binding for [3H]-prazosin, and the pA2-values (negative logarithm of dissociation constant) of clonidine and prazosin against noradrenaline were not influenced by cooling. 3. These results indicate that cooling did not influence the affinity of a competitive antagonist and receptor concentration. 4. Cooling increased the dissociation constant of noradrenaline but decreased its efficacy. 5. A receptor occupancy-response curve for noradrenaline was a rectangular hyperbola at 37 degrees C but linear at 25 degrees C, suggesting that a relationship between the contractile response and receptor occupancy was changed by cooling.

Animals↗
PubMed1988

Telemetric detection of cardiac allograft rejection. Correlation of electrophysiological, histological, and biochemical changes during unmodified rejection.

Intra-abdominal mismatched heterotopic cardiac allograft transplantation without immunosuppression was performed in eight pigs. Postoperatively, daily electrophysiological studies were carried out either with exteriorized temporary epicardial pacing wires (n = 4) or by a telemetrically controlled implanted pacemaker connected to permanent epicardial pacing leads (n = 4). Electrophysiological studies data were correlated with histopathologic and biochemical findings from daily myocardial biopsies. Electrophysiological studies revealed no significant alteration of sinus or atrioventricular node function, refractoriness, or ventricular pacing threshold. However, ventricular voltage amplitude, measured through the electrodes, decreased steadily with time in all donor hearts and was significantly correlated with histopathologic rejection grade (p less than 0.001) and with adenosine 5'-triphosphate (ATP) depletion (p less than 0.001). Ventricular voltage amplitude less than 75% of baseline occurred 4.5 +/- 1.5 days after transplantation, and this decreased voltage amplitude coincided with a moderate to severe (Grade 2 or 3) histological rejection pattern with a sensitivity of 89% (17 of 19) and a specificity of 77% (17 of 22). Similar changes in voltage amplitude were not found in control hearts. Myocardial tissue ATP values fell significantly from control values with early (Grade 1) rejection (p less than 0.05). Evidence for oxygen free radical injury was indicated by a rise in conjugated dienes of free fatty acids; this increase in diene level occurred 4.3 +/- 1.2 days postoperatively and then regressed during the terminal stages.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗