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Biomedical subjects

A Ohbayashi

Publications and source records attributed to A Ohbayashi.

16 recordsLinked to original sources
PubMed1994

Characteristics of porcine coronary artery endothelial cells in culture: comparison with aortic endothelium.

In the present study we compared the characteristics of porcine coronary artery endothelial cells in culture with the characteristics of aortic endothelium. Morphologically, coronary artery endothelial cells were larger than aortic endothelial cells. Under basal culture conditions, both coronary artery and aortic endothelial cells secreted significant amounts of prostacyclin and endothelin-1. The outstanding findings is that coronary artery endothelial cells secreted larger amounts of endothelin-1 than aortic endothelial cells. Immunofluorescence staining revealed that individual endothelial cells synthesize both substances. This comparative study provides important evidence indicating that the characteristics of coronary artery endothelial cells differ from those of aortic endothelial cells.

Animals↗
PubMed1993

A comparative study of urinary xanthopterin and neopterin in liver diseases.

By adsorption to activated charcoal, various pteridine derivatives in human urine are oxidized to xanthopterin. Following this oxidation, xanthopterin in urine from healthy subjects and from patients with liver diseases was assayed by high performance liquid chromatography. The mean values for xanthopterin in healthy subjects were 532 +/- 116 mumol/mol creatinine (mean +/- SD) in males and 585 +/- 153 mumol/mol creatinine in females; the difference was statistically significant (p < 0.01). Xanthopterin concentrations in patients with liver disease were significantly higher than those in normal subjects. When compared with urinary neopterin, which is a marker of activated cell immunity, xanthopterin was significantly increased even in fatty liver disease. These findings suggest that increased concentrations of urinary xanthopterin in liver diseases reflect not only the status of activated cell-mediated immunity, but also injury to liver cells.

Adult↗
PubMed1991

[Comparative studies on immunogenicity of Chinese hamster ovary cell derived HB vaccine and plasma derived HB vaccine].

Chinese Hamster Ovary Cell derived HB vaccine (CDV) and plasma derived HB vaccine (PDV) were separately given to two groups of 131 and 112 medical stuff subjected, and both the anti-HBs responses were observed for 24 months from the time of first injection. The anti-HBs positive rate at the 7th month was 97% (mean geometric anti-HBs concentration 588 IU/L) in CDV group and 78% (83 IV/L) in PDV group, and the positive rate and mean titer of anti-HBs were always higher for 24 months in CDV group. The differences were remarkable between both the subjects aged over 40 years. The decreasing curves of the anti-HBs titer in the two groups were almost parallel; accordingly, the protective efficacy was estimated to be far longer in CDV. Also, the rate of non-responder was less lower (2.8%) in CDV group than that (15.2%) in PDV group. Above results show that CDV has a higher immunogenicity than PDV.

Adult↗
PubMed1991

Purification and characterization of rice peroxidases.

Four peroxidase components, named RP-2, 4, 6, and 7, were isolated from rice (Oryza sativa L.) green leaves. Isoelectric focusing indicated that each preparation was homogeneous. The molecular weights of RP-2, 4, 6, and 7 estimated by SDS-PAGE were 48,000, 48,000, 40,000, and 39,500, and their isoelectric points were 5.4, 8.1, 9.3, and 9.2, respectively. The activity of every preparation was maximum around pH 5.0. Antisera against these purified enzymes were raised in rabbits. Ouchterlony double diffusion tests with these antisera suggested that RP-6 and 7 were immunochemically identical and RP-2 and 4 were identical in parts and that RP-6 and 7 were quite different from RP-2 and 4. Analysis of the N-terminal amino acid sequences also showed that these peroxidase components were classified into two groups. The polymerase chain reaction showed that RP-2 and/or RP-4 contained an active central region, which is homologous to other plant peroxidases.

Amino Acid Sequence↗
PubMed1990

Hepatitis C viral cDNA clones isolated from a healthy carrier donor implicated in post-transfusion non-A, non-B hepatitis.

Using a specific hepatitis C virus (HCV) antibody assay, positive blood donors responsible for the transmission of post-transfusion non-A, non-B hepatitis (PT-NANBH) were identified. cDNA fragments were isolated from one of the plasma samples of such healthy HCV carriers by using polymerase chain reactions. Nucleotide (nt) sequence analyses of the cDNA from three different regions of the viral genome revealed that they were derived from a Japanese HCV isolate that was similar but not identical to the prototype HCV previously isolated from a chronically infected chimpanzee. Homology at the nt and amino acid levels was comparatively lower in the presumed structural region than in putative nonstructural regions. This result not only confirms that HCV antibody-positive blood contains infectious HCV, but suggests the existence of different type(s) of HCV.

Amino Acid Sequence↗
PubMed1990

Hepatitis C virus infection is associated with the development of hepatocellular carcinoma.

A possible causative role for the recently discovered hepatitis C virus (HCV) in the development of hepatocellular carcinoma (HCC) was investigated by assay of sera from HCC patients in Japan for antibodies to a recombinant HCV antigen and to hepatitis B virus (HBV) antigens. Among the 253 HCC patients examined, 156 (61.7%) had no serum markers of either a previous or a current HBV infection (group I), 46 (18.2%) were negative for HBV surface antigen but positive for anti-HBV surface and/or anti-HBV core antibody, indicating the occurrence of a previous, transient HBV infection (group II), and 51 (20.2%) were chronically infected HBV carriers as evidenced by positivity for HBV surface antigen (group III). The prevalence of HCV antibody in group I (68.6%) and II (58.7%) patients was significantly higher than for group III (3.9%) or in 148 additional patients with other (non-HCC) cancers (10.1%) (P less than 0.01). Thus, there appears to be a strong association between HCV infection and the development of HCC, particularly in patients for which HBV infection cannot be implicated as a causative factor. The data also suggest an additional mode of transmission for HCV other than blood transfusion, since a history of blood transfusion was shown in only about 30% of the HCV antibody-positive HCC patients in groups I and II. A high prevalence of HCV antibody was also shown among patients with HCC whose disease was originally thought to be due to very high ethanol consumption.

Blood Transfusion↗
PubMed1990

Detection of hepatitis C virus cDNA sequence by the polymerase chain reaction in hepatocellular carcinoma tissues.

We found the presence of hepatitis C virus (HCV) infection in liver tissues of hepatocellular carcinoma (HCC) patients who had antibodies to HCV but no serological markers for hepatitis B virus infection by the sensitive reverse transcription/polymerase chain reaction (R/PCR) method. The primers used were derived from the non-structural (NS) 3 and/or the structural (C/E) region. Amplified cDNA sequences of HCV were detected in either cancerous or non-cancerous portion of liver tissues from four out of eight HCC patients with primers of NS3 region. Similar but less efficient results were obtained with primers of C/E region. These results indicate that HCV persists in the liver tissue of HCC. A possible role of persistent infection of HCV for the development of HCC is discussed.

Base Sequence↗
PubMed1989

Suppression of the activities of T-lymphocyte-related enzymes in spleen by administration of an immunosuppressant, 15-deoxyspergualin.

We investigated the effects of both (-) and (+)-enantiomers of 15-deoxyspergualin (DSG), an immunosuppressant, on enzyme networks in spleens of ICR mice. Of the 14 hydrolytic enzymes tested, the activity of dipeptidyl aminopeptidase IV (DAP-IV) was found to be significantly suppressed by the administration of (-)-DSG but not by that of (+)-DSG. In contrast, the activity of N-acetyl-beta-D-glucosaminidase (GlcNAc-ase) was suppressed by the administration of both enantiomers of DSG. Judging from the previous reports of ours and others which suggested specific relations of these enzymes to T-lymphocytes, the above findings may warrant further studies of these enzymes in relation to immunologic functions of the body.

Acetylglucosaminidase↗
PubMed1982

[Considerations on familial clustering of liver cirrhosis and hepatocellular carcinoma].

It has been shown here that familial occurrences of liver cirrhosis and hepatocellular carcinoma (HCC) are frequent in Japan. The observations have suggested that, in those families, hepatitis B virus (HBV) infections occurred frequently among the family members, mainly from mother to infant, and that many of the infected persons became HBV carriers; subsequently, some of them developed chronic hepatitis, liver cirrhosis and eventual HCC in their adults. In such pedigrees, susceptibilities to cirrhosis, and also to HCC may be inherited in addition to successive transmission of HBV.

Adolescent↗