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H Nakabayashi

Publications and source records attributed to H Nakabayashi.

At least 37 records · Page 2Linked to original sources
PubMed1997

Neural monitoring system for circulating somatostatin in the hepatoportal area.

If a peptide hormone secreted from the gastroenteropancreatic (GEP) system is monitored by the hepatic vagal nerve, the nerve can signal the central nervous system and thereby exert control on its target organs. In this review, we offer a line of evidence for the hypothesis. When a physiological dose of somatostatin (SS), one of the GEP hormones, was injected into the rat portal vein, the spike discharge rate in the hepatic afferent vagus increased significantly. This SS-induced activation of the vagus was completely abolished by a prior administration of our monoclonal antibody to SS receptor into the portal vein. We further disclosed a morphological basis for this neural reception to SS in the hepatoportal area: the neural bodies, located beneath the endothelium of the rat portal vein, preferentially bound the exogenous SS injected intraportally as revealed immunohistologically. The bodies contained a structure of the nerve fiber arborizations resembling those of the afferent apparatus of Krause, on which the presence of SS receptor was confirmed histochemically using the anti-SS receptor antibody. These results provide a new insight into the receptor-mediated neural reception to GEP hormones in the hepatoportal area, implying the potential role of the reception in the GEP physiology.

Animals↗
PubMed1996

The hepatic vagal nerve is receptive to incretin hormone glucagon-like peptide-1, but not to glucose-dependent insulinotropic polypeptide, in the portal vein.

To examine whether incretin hormones, truncated glucagon-like peptide-1 (tGLP-1) and glucose-dependent insulinotropic polypeptide (GIP), are recognized by the hepatic vagal nerve, changes of the impulse discharge rate in the afferent vagus upon their intraportal administrations were measured in situ in rats anesthetized with urethan and chloralose. One-min injection of tGLP-1 at a periphysiological dose of 0.2 pmol or a pharmacological dose of 4.0 pmol, but not of the vehicle, significantly facilitated the hepatic vagal afferents. However, the injection of GIP at either a physiological dose of 0.2 pmol, a periphysiological dose of 4.0 pmol, or an even much larger dose of 40.0 pmol did not change the afferents at all. The present results indicate that the hepatic vagus specifically recognizes an intraportal appearance of tGLP-1 in the hepatoportal area, suggesting that the vagal monitoring system for intraportal levels of the incretin hormone operates on ingestion of a mixed meal.

Afferent Pathways↗
PubMed1996

Early calcium signaling and calcium requirements for the IL-2 receptor expression and IL-2 production in stimulated lymphocytes.

Two kinds of lymphocyte populations were prepared from human resected tonsils: one was a mixed population consisting of T cells, B cells, other lymphocytes, and a few macrophages, and the other was a T-enriched population obtained by removing adherent cells from the mixed population with a nylon wool column. A transient rise in cytosolic free calcium ion concentration ([Ca2+]i) was observed in both the populations within a few minutes of stimulation with concanavalin A (Con A). However, emergence of cells which had high [Ca2+]i after 4 min of Con A stimulation was observed practically only in the mixed population. The [Ca2+]i elevation occurring within a few minutes of stimulation in both populations was interpreted as being due to a release from the intracellular Ca-storing organelles, whereas the high [Ca2+]i in a group of cells after 4 min of Con A stimulation in the mixed population was caused by an influx of extracellular calcium that probably corresponds to a transient enhancement of Ca2+ uptake observed only in the mixed population during early stimulation. Con A induced both interleukin 2 receptor (IL-2R) expression and interleukin 2 (IL-2) production. A nonmitogenic lectin, wheat germ agglutinin (WGA), also induced a rise in the [Ca2+]i within a few minutes. WGA induced IL-2 production, but did not induce IL-2R expression. Chelation of extracellular calcium with EGTA at the time of Con A addition resulted in a decrease in IL-2R expression, IL-2 production, and DNA synthesis, but not when CaCl2 equimolar to EGTA was present in the culture medium. Chelation of calcium 12 hr after Con A stimulation decreased IL-2R expression, but had no effect on IL-2 production. These results indicate that IL-2 production required Ca2+ only in the early (G0) stage and that IL-2R expression was dependent on Ca2+ in both the G0 and the G1 stages.

Calcium↗
PubMed1996

Gene therapy for alpha-fetoprotein-producing human hepatoma cells by adenovirus-mediated transfer of the herpes simplex virus thymidine kinase gene.

We have developed a recombinant replication-defective adenovirus containing human alpha-fetoprotein (AFP) promoter/enhancer to direct cell type-specific expression of the herpes simplex virus thymidine kinase (HSVtk) gene to AFP-producing hepatocellular carcinoma (HCC) cells. After an in vitro infection by a recombinant adenovirus carrying the lacZ gene under the control of human AFP promoter/enhancer (AdAFPlacZ), an expression of the lacZ gene was demonstrated efficiently in AFP-producing HuH-7 and HepG2 cell lines, but not in AFP-nonproducing HLE and HLF cell lines, although lacZ gene expression was demonstrated in all these cell lines when infected with adenovirus vector carrying lacZ gene driven by the beta-actin-based promoter. Expression of the HSVtk gene by adenovirus, from AFP promoter/enhancer (AdAFPtk) induced the cells sensitive to ganciclovir (GCV) in the AFP-producing cell line efficiently, but not in AFP-nonproducing HLF hepatoma cells. An in vitro bystander effect was observed when only 10% of the cells were infected with AdAFPtk. These findings suggest that the AFP promoter/enhancer sequence can provide the tumor-specific activity for the therapeutic gene expression, and that the AdAFPtk vector induces the selective growth inhibition by GCV in the adenovirus-infected human hepatoma cells in vitro. Recombinant adenovirus transfer of the HSVtk gene under the control of tumor-specific promoter followed by GCV may have promise as a targeted in situ treatment for solid neoplasms.

Adenoviridae↗
PubMed1996

Expression ratio of hepatocyte nuclear factor-1 to variant hepatocyte nuclear factor-1 in differentiation of hepatocellular carcinoma and hepatoblastoma.

BACKGROUND/AIMS: Liver-specific protein genes have multiple cis-/trans-acting elements, but those accountable for hepatocytic differentiation are unclear. An AT-rich core sequence (AT motif) is essential as a cis-acting element for the hepatic transcription. Homologous proteins hepatocyte nuclear factor-1 (HNF-1) and variant HNF-1 (vHNF-1) bind to this motif. The ratio of HNF-1 to vHNF-1 mRNA was examined in various liver tissues with respect to their differentiation. METHODS: The competitive reverse transcriptional polymerase chain reaction was employed to amplify HNF-1 and vHNF-1 mRNA simultaneously and to examine their expression ratio in total RNA extracted from frozen liver tissues of 37 patients with hepatocellular carcinoma, five patients with hepatoblastoma, and 15 non-neoplastic liver tissues. RESULTS: The ratio of HNF-1 to vHNF-1 mRNA was higher in well-differentiated cases than in poorly-differentiated and undifferentiated cases, except that one poorly-differentiated hepatoblastoma displayed a high ratio. Non-neoplastic liver tissues had low ratios similar to poorly-differentiated hepatocellular carcinoma, the reason for which remained unknown. However, chronic hepatitis and liver cirrhosis cases also demonstrated low ratios, and hence degenerative changes themselves displayed no obvious influence on such ratios. Thus, the gene expression of HNF-1 and vHNF-1 seemed to be differentially regulated in neoplastic and non-neoplastic hepatocytes. CONCLUSIONS: These results suggested that the ratio of HNF-1 to vHNF-1 mRNA correlated with histological differentiation of HCC and hepatoblastoma.

Adult↗
PubMed1996

Vagal hepatopancreatic reflex effect evoked by intraportal appearance of tGLP-1.

Among proglucagon-derived peptides, the truncated form of glucagon-like peptide-1, GLP-1(7-36)amide (tGLP-1), is known as the most likely physiological humoral incretin. To examine whether there exists any relationship between tGLP-1 levels in the portal vein and activities of the hepatic and pancreatic vagal system, changes of the impulse discharge rate in the hepatic afferent vagus and the pancreatic efferent vagus upon intraportal tGLP-1 injection were measured in situ in rats anesthetized with urethan and chloralose. First, a 1-min bolus tGLP-1 injection at a periphysiological dose of 0.2 pmol or a pharmacological dose of 4.0 pmol, but not the vehicle injection, significantly facilitated the hepatic vagal afferents for > 90 min, showing weaker facilitation at the 0.05 pmol dose. Notably, the injection of noninsulinotropic full-length GLP-1 failed to facilitate the afferents at the 4.0 or 40.0 pmol dose. Second, the intraportal tGLP-1 injections at the 0.05 and 0.2 pmol dose facilitated marginally and significantly the pancreatic vagal efferents in normal rats, respectively, but had no effect on the hepatic vagotomized rats, even at the 40.0 pmol dose. The present results indicate that an intraportal appearance of tGLP-1 is specifically recognized by the hepatic vagal nerve, and this recognition further augments the pancreatic vagal efferent activity in a reflex way, suggesting another nature of tGLP-1 as neuroincretin in the enteroinsular axis.

Afferent Pathways↗
PubMed1996

A possible common cell surface autoantigen in islet beta-cells and thyroid follicular cells in patients with non-insulin dependent diabetes mellitus and chronic thyroiditis.

By an indirect immunofluorescence method with In-111 cells (hamster insulinoma cell line), circulating islet cell surface antibodies (ICSA) were detected in 7 (20%) out of 36 patients with non-insulin dependent diabetes mellitus (NIDDM), 9% of 68 chronic thyroiditis (CT) patients, or 16% of 19 NIDDM patients associated with CT, but not in 18 normal subjects. Sera from five out of nine ICSA-positive patients examined further also showed cell-surface immunofluorescence on TPC-1 cells (human thyroid papillary adenocarcinoma cell line), and prior absorption of the sera with In-111 cells abolished the immunofluorescence. The 64 kDa protein from In-111 cells or human thyroid follicular cells was immunoprecipitated with ICSA-positive sera. In one case of NIDDM associated with CT, 64 kDa protein was detected in both cells. The results indicate that some ICSA in NIDDM patients recognize the same or a very closely-related autoantigen(s) in both islet beta-cells and thyroid follicular cells, suggesting an explanation, at least in part, for the autoimmune mechanism(s) in clinical association of NIDDM and CT.

Adenocarcinoma, Papillary↗
PubMed1996

[Detection of p27/kip1 mRNA in blood cells by nonradioactive ribonuclease protection assay].

Cyclin and cyclin-dependent kinase(cdk) complexes, and their inhibitors (CKIs) play important roles in growth regulation on the cells. p27/kip1 is a CKI associated with G1 arrest induced by cell to cell contact, transforming growth factor-beta and cyclic AMP. The abnormality of p27/Kip1 genes in human tumors usually appears as a steady level defect of expression, since mutations in them is rare. Thus it is important to estimate the expression level of this gene. To detect the change of p27/Kip1 mRNA level in blood cells, we developed the ribonuclease protection assay using nonradioactive riboprobe which was produced by reverse transcriptase-polymerase chain reaction (RT-PCR) with T7 promoter-added antisense primer and the in vitro transcription system. Our assay may be useful for clinical evaluation of the mRNA level.

Base Sequence↗
PubMed1996

[Regulation of tumor marker gene expression].

Tumor marker is a group of proteins that specifically expressed in association with carcinogenic processes. Thus, studies of regulation mechanisms of the tumor marker genes are important for understanding the possible alteration of gene expression during neoplastic transformation. In this article, we described the molecular mechanisms of the regulation of two major tumor marker genes, i.e. human alpha-fetoprotein (AFP) gene and rat glutathione transferase P(GST-P) gene. Positive and negative mechanisms of each gene regulations are discussed.

Animals↗
PubMed1995

Adenovirus-mediated gene therapy of hepatocellular carcinoma using cancer-specific gene expression.

Most patients with hepatocellular carcinoma have an elevated alpha-feto-protein (AFP) level. This high level of AFP expression is transcriptionally controlled by the 5'-flanking sequence of the AFP gene. Using the 5'-flanking sequence as a promoter for the herpes simplex virus thymidine kinase (HSV-TK) gene in an adenoviral vector (Av1AFPTK1), the therapeutic efficacy of adenovirus-mediated HSV-TK gene transduction, followed by ganciclovir (GCV) administration, was studied in tumors in athymic nude mice. Av1AFPTK1 transduction of two cell lines demonstrated HSV-TK enzyme activity only in the AFP-producing cells (HuH7) and not in the AFP nonproducing cells (SK-Hep-1). As expected, only transduced HuH7 cells were killed by GCV treatment. Transduction by an adenoviral vector harboring a Rous sarcoma virus promoter and HSV-TK gene (Av1TK1) showed enzymatic activity and GCV killing in both cell lines. All HuH7 tumors that were transduced with either Av1AFPTK1 or Av1TK1 completely regressed after GCV treatment. On the other hand, there was complete regression of SK-Hep-1 tumors only when treated with Av1TK1 and GCV and not when treated with Av1AFPTK1 and GCV. Thus, cell-specific killing was achieved by adenoviral vector containing AFP promoter for the HSV-TK gene and GCV treatment.

Adenoviridae↗
PubMed1995

Isolation and sequence polymorphism of a rat retinoblastoma (RB) cDNA.

A cDNA of the rat retinoblastoma gene (RB) was prepared from total RNA of rat liver using reverse transcription-polymerase chain reaction (RT-PCR). The 4432-nt sequence isolated contained 2700-nt translated and 1732-nt 3'-untranslated regions (UTR). The isolated cDNA detected poly(A)+RNAs of 5.4 and 3.4 kb in rat liver and kidney by Northern blot hybridization. The nt sequence of the isolated cDNA had 85% homology with that of mouse and 73% with human. The 899-amino-acid (aa) sequence was 95% homologous to that of mouse and 90% to human. The aa sequences of two functional domains of oncoprotein-binding and ten putative phosphorylation sites regulating RB function were conserved in the three species. However, the 3'-UTR were less homologous among the three, and had polymorphism in three portions, even in rats. These polymorphisms were strain-specific and genetically segregated. Thus, the rat RB cDNA and its sequence information may be useful for clarifying the role of the RB protein and genetic linkage analysis in basic biomedical research using rats, especially in experimental carcinogenesis.

Amino Acid Sequence↗
PubMed1995

[Microsatellite polymorphism of muscle glycogen synthase gene and non-insulin dependent diabetes mellitus].

It has been reported recently that A2 allele of muscle glycogen synthase gene determined by Xba I RFLP (restriction fragment length polymorphism) is related to the frequency of NIDDM in Finland. Using PCR-RFLP analysis, we detected no A2 allele in Japanese patients with NIDDM and control. We found a new microsatellite of CA repeat in the human muscle glycogen synthase gene, and the polymorphism of the repeat number was detected by the polymerase chain reaction. Six different alleles were observed, indicating the highly polymorphic nature of this marker. We analyzed the repeat numbers and the genotypes in diabetics and control. The allele frequencies were not significantly different between NIDDM and control. However, the allele frequencies in the patients without high total cholesterolemia was significantly different from those of control. These findings suggest that the muscle glycogen synthase gene or neighboring genes are related to one of the disease genes of diabetes mellitus without high total cholesterolemia.

Adolescent↗
PubMed1995

Reduced dimerization of lipoprotein lipase in post-heparin plasma of a patient with hyperchylomicronemia.

As in post-heparin plasma of control subjects, post-heparin plasma of a patient with hyperchylomicronemia contained lipoprotein lipase (LPL) subunits with M(r) = 57,000. But although the amount of LPL was the same as in post-heparin plasma of controls, no LPL activity was detectable. Nearly all the LPL in post-heparin plasma of controls bound to heparin-Sepharose and this LPL bound was mainly eluted with 1.5 M NaCl in parallel with the activity. In post-heparin plasma of the patient, 58% of the LPL subunits did not bind to heparin-Sepharose and 23% was eluted with 0.6 M NaCl. Studies by sucrose density gradient centrifugation showed that almost all the LPL in post-heparin plasma of controls was recovered in the peak with a sedimentation coefficient of 6.8 S, corresponding to the position of a dimeric form of LPL, in parallel with the activity; little LPL was recovered in the peak with a sedimentation coefficient of 4.0 S, corresponding to the position of a monomeric form of LPL. In post-heparin plasma of the patient, 35% of the LPL subunits was recovered in fractions with larger sedimentation coefficients at the bottom of the centrifuge tube, indicating the presence of an aggregated form(s) of LPL; the amount of the monomeric form of LPL was increased, while that of the dimeric form was decreased. Thus, defect of LPL activity in post-heparin plasma of the patient with hyperchylomicronemia could result from reduced dimerization of LPL subunits.

Adolescent↗
PubMed1995

Somatostatin receptor on the afferent nerve terminals in the rat hepatoportal area.

To determine whether somatostatin receptor (SSR) actually exists on the nerve terminals in the rat hepatoportal area, the area was immunostained by the labeled streptoavidin-biotin complex method using a monoclonal antibody against rat brain SSR. The SSR staining revealed many fiber arborizations with terminal nodular swellings like the afferent nerve endings in the neural body, which was located beneath the endothelium of the large branches of the intrahepatic portal vein. The results indicate that SSR is expressed on the characteristic structure, adding further evidence for our previous observation which showed the hepatic vagal reception for intraportal somatostatin and the somatostatin-binding neural body as a relevant structure.

Afferent Pathways↗
PubMed1995

Proliferative potential of meningiomas evaluated by proliferating cell nuclear antigen expression.

Meningiomas are principally benign in nature. Some meningiomas, however, grow fast or recur even after total removal. The biological behavior of meningiomas often can not be predicted from conventional histopathological studies. A monoclonal antibody against proliferating cell nuclear antigen (PCNA) was used to investigate the usefulness of the PCNA index as a parameter to estimate the proliferative activity of meningiomas. Fifty-two meningiomas were examined. The mean PCNA index of recurrent meningiomas (3.37 +/- 0.92%) was significantly higher than that of non-recurrent meningiomas (1.12 +/- 0.51%) (p < 0.005). The PCNA indices of recurrent cases were all higher than 2.0%. A semilog linear regression analysis between tumor doubling time and PCNA index showed a significant correlation (r = 0.90, p < 0.05). An inverse linear correlation between PCNA index and interval to recurrence was observed (r = 0.62, p < 0.05). A good linear correlation was also shown between PCNA index and BUdR labeling index (r = 0.88, p < 0.01). The results of this study suggest that, providing the methods of tissue processing, immunostaining and counting of positive nuclei are unified, the PCNA index is a useful parameter for estimating the biological behavior of meningiomas.

Adult↗
PubMed1995

Defective copper binding to apo-ceruloplasmin in a rat model and patients with Wilson's disease.

To examine the mechanism of decrease in serum ceruloplasmin (Cp) in Long-Evans Cinnamon (LEC) rats, a proposed model of Wilson's disease, we analyzed Cp products at the stages of transcription and translation. Northern blot analysis and immunoblot analysis showed that the level and the molecular size of Cp mRNA and protein in LEC rats were similar to those in control Long-Evans-Agouti (LEA) rats. However, the ferroxidase activity of Cp was significantly decreased in LEC rats. We separated serum Cp into two forms by native polyacrylamide gel electrophoresis with pH modification: one was a holo-Cp with copper and ferroxidase activity, and the other was an inactive apo-Cp without copper. Holo-Cp was the predominant form in LEA rats and normal humans, whereas apo-Cp was the major form in LEC rats and patients with Wilson's disease. The cosegregation of apo-Cp predominance with the disease in LEC rats was analyzed using backcross rats. Apo-Cp was dominant in 8 of 11 offspring with disease but in none of 19 normal offspring. These results indicate that a genetic disturbance of copper binding to apo-Cp may be closely associated with the pathogenesis in LEC rats, and probably in Wilson's disease.

Animals↗