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Biomedical subjects

T Sugano

Publications and source records attributed to T Sugano.

At least 127 records · Page 7Linked to original sources
PubMed1988

Ca2+-dependent activation of the malate-aspartate shuttle by norepinephrine and vasopressin in perfused rat liver.

The role of Ca2+ in stimulation of the malate-aspartate shuttle by norepinephrine and vasopressin was studied in perfused rat liver. Shuttle capacity was indexed by measuring the changes in both the rate of production of glucose from sorbitol and the ratio of lactate to pyruvate during the oxidation of ethanol. (T. Sugano et al. (1986) Amer. J. Physiol. 251, E385-E392). Asparagine (0.5 mM), but not alanine (0.5 mM) decreased the ethanol-induced responses. Norepinephrine and vasopressin had no effect on the ethanol-induced responses when the liver was perfused with sorbitol or glycerol. In the presence of 0.25 mM alanine, norepinephrine, vasopressin, and A23187 decreased the ethanol-induced responses that occurred with the increase of flux of Ca2+. In liver perfused with Ca2+-free medium, asparagine also decreased the ethanol-induced responses, but norepinephrine and vasopressin had no effect. Aminooxyacetate inhibited the effects of norepinephrine, A23187, and asparagine. Regardless of the presence or absence of perfusate Ca2+, the combination of glucagon and alanine had no effect on the ethanol-induced responses. Norepinephrine caused a decrease in levels of alpha-ketoglutarate, aspartate, and glutamate in hepatocytes incubated with Ca2+. The present data suggest that the redistribution of cellular Ca2+ may activate the efflux of aspartate from mitochondria in rat liver, resulting in an increase in the capacity of the malate-aspartate shuttle.

Alanine↗
PubMed1988

Gluconeogenesis in perfused chicken kidney. Effects of feeding and starvation.

1. Starvation for 48 hr doubled the rate of gluconeogenesis from lactate and pyruvate in perfused chicken kidney, but did not change the rate of production of glucose from malate, succinate, or alpha-ketoglutarate. 2. Amino-oxyacetate and D-malate inhibited the production of glucose from lactate and from pyruvate by 55% in each case. Quinolinate reduced the production of glucose from lactate and from pyruvate by 50% in both fed and starved chickens, but had no effect on the production of glucose from intermediates in the citric acid cycle. 3. Starvation increased the rate of formation of mitochondrial phosphoenolpyruvate from pyruvate, but had no effect on the rate of formation of mitochondrial phosphoenolpyruvate from malate.

Animals↗
PubMed1988

Effects of cold exposure on inhibition by isoproterenol of release of alanine in the rat.

The effects of isoproterenol on the release of alanine during perfusion with pyruvate and valine were studied in perfused hindlimbs from rats that had been kept for 5 or 20 days at 4 degrees C. In hindlimbs perfused with Krebs bicarbonate buffer in a flow-through mode, the rate of release of alanine during perfusion with 2 mM pyruvate plus 5 mM valine was 250 nmol.min-1.leg-1, a rate that is comparable with that reported in hindlimbs perfused with complex medium. Neither the pyruvate-stimulated nor valine plus pyruvate-stimulated rates of release of alanine changed after 20 days of exposure to cold. Isoproterenol inhibited the release of alanine during perfusion with pyruvate, with valine, and with valine plus pyruvate in hindlimbs from a control group of rats. However, in hindlimbs from cold-exposed groups, isoproterenol failed to inhibit the release of alanine during perfusion with valine plus pyruvate and stimulated the release of alanine during perfusion with valine. Aminooxyacetate inhibited the effects of valine, pyruvate, and isoproterenol. The results obtained suggested that cold exposure decreases the responses to isoproterenol of the mechanism of alanine release and causes an increased supply of alanine to the liver.

Alanine↗
PubMed1987

Hybridomas producing human monoclonal antibodies against varicella-zoster virus.

Hybridomas producing human monoclonal antibodies (mAb) against varicella-zoster virus (VZV) were generated by fusing human splenic lymphocytes with mouse myeloma cells. Before cell fusion, lymphocytes were stimulated in vitro with viral antigens and pokeweed mitogen. This combination synergistically increased the generation of VZV-specific hybridomas. Five established hybridomas have been stably producing mAb for at least 9 months. These mAb, designated V1, V2, V6, V8 and V9, were of the IgG1, lambda isotype. They bound to all 6 tested VZV strains but not to other herpes viruses, with the exception that V1 bound to herpes simplex virus (HSV) as well as VZV. Immunoprecipitation analysis showed that V1, V6 and V9 recognized glycoprotein gpII, whereas V2 and V8 recognized gpI. In addition, V1 reacted with the gB glycoprotein of HSV. All these mAb neutralized viral infectivity. The neutralizations by V2 and V8 were more effective and more complement dependent than those by V1, V6 and V9. Immunofluorescence tests revealed that all these mAb bound to the surface membrane of VZV-infected cells. These results suggest that cell fusion between in vitro stimulated lymphocytes and mouse myeloma cells is a reliable method for the generation of hybridomas capable of stable production of human mAb. The human mAb thus developed may provide a new means of passive immunization of humans against VZV infection.

Antibodies, Monoclonal↗
PubMed1987

Antiviral activities of human monoclonal antibodies to herpes simplex virus.

Hybridomas producing human monoclonal antibodies (MAbs) against herpes simplex virus (HSV) were established by fusing human tonsillar lymphocytes with mouse myeloma cells. Three hybridomas have been stably producing MAbs for more than 16 months. All three MAbs--H1, H2, and H3--were of the IgG1 isotype and recognized the gB glycoprotein of HSV types 1 and 2 (HSV-1 and HSV-2). MAbs H2 and H3 not only bound to the surface membrane of HSV-infected cells but also neutralized both HSV-1 and HSV-2, whereas MAb H1 had neither activity. In mouse infection experiments, MAbs H2 and H3 showed a potent protective effect against HSV-1 infection, whereas MAB H1 was less protective. Furthermore, the development of zosteriform skin lesions in athymic nude mice was suppressed by administering MAb H2. These results suggest that human MAbs might provide passive immunization against HSV infections in humans.

Animals↗
PubMed1987

Human monoclonal antibodies neutralizing human cytomegalovirus.

Hybridomas producing human monoclonal antibodies (MAbs) against human cytomegalovirus (CMV) were generated by fusion of human spleen cells and mouse myeloma cells. Two of the six MAbs obtained neutralized viral infectivity even at concentrations lower than 1 microgram/ml. One MAb required complement for neutralization but the other did not. Both MAbs recognized viral proteins of Mr 130,000 and 55,000. Furthermore, these neutralizing MAbs bound to the surface membrane of CMV-infected cells. These results suggest that human MAbs may provide a new means of passive immunization against CMV infection in humans.

Antibodies, Monoclonal↗
PubMed1987

Detection of specific antibodies against fimbriae and membrane proteins from the oral anaerobe Bacteroides gingivalis in patients with periodontal diseases.

Sera from a number of patients with periodontal diseases were shown to have specific immunoglobulin G (IgG) antibodies against fimbriae and membrane proteins of Bacteroides gingivalis, a suspected pathogen, by using Western blottin analysis. The sera had a strong tendency to react with fimbriae, or exactly oligomeric structures of fimbriae with a native beta-structure rich-conformation. However, the sera did not react with fimbrilin, a constituent protein of fimbriae, which is denatured by sodium dodecyl sulfate.

Adult↗
PubMed1987

Distribution of glycolysis and gluconeogenesis in perfused chicken kidney.

Regional metabolism of glucose in chicken kidneys was studied in kidneys perfused with either an arterial system or a portal system. Provided that kidneys were perfused with oxygenated buffer solution at a flow rate of 5 ml/min per gram of kidney in both perfusion systems, oxygenation of the kidney was achieved, as judged by the rates of O2 uptake and the formation of lactate, gluconeogenesis, and the ratio of lactate to pyruvate. The rate of formation of lactate and pyruvate during glucose metabolism, in the presence or absence of KCN, was markedly higher with the arterial system than with the portal system. The rate of gluconeogenesis was equal with both perfusion systems but the rate was modulated by the type of substrate used. With succinate as substrate, ouabain inhibited glucose production and O2 uptake in both perfusion systems. With lactate and pyruvate as substrate, ouabain had no effect on glucose production in both perfusion systems, whereas the inhibition of O2 uptake by ouabain was greater with the arterial system than with the portal system. From the viewpoint of the accepted morphological components of the blood supply, these results suggest that chicken renal gluconeogenesis occurs in the cortex and that glycolysis occurs in medullary structures.

Aerobiosis↗
PubMed1987

[Antibacterial activities of arbekacin, a new aminoglycoside antibiotic, against methicillin-cephem-resistant Staphylococcus aureus].

The in vitro and in vivo antibacterial activities of a new aminoglycoside antibiotic, arbekacin (HBK), against methicillin-cephem-resistant Staphylococcus aureus (MRSA) were compared with those of gentamicin (GM), netilmicin (NTL) and amikacin (AMK). The results obtained were summarized as follows: Compared to other aminoglycoside antibiotics, HBK had the highest antibacterial activities against clinically isolated MRSA (46 strains). Therapeutic effects of HBK against experimental systemic infections with MRSA in mice, were superior to those of GM, NTL and AMK. The ED50's of GM, NTL and AMK were more than 2 mg/mouse. Therapeutic effects of HBK against experimental subcutaneous infections with MRSA in mice were also superior to those of GM, NTL and AMK.

Abscess↗
PubMed1986

Generation of hybridomas producing human monoclonal antibodies against human cytomegalovirus.

In vitro stimulation of human lymphocytes were studied in connection with cell fusion. When splenic lymphocytes were stimulated with human cytomegalovirus (CMV), they produced IgG but not IgM antibody against CMV. The stimulation with 50 ng/ml of CMV antigen induced the maximum antibody response, and higher concentrations of CMV antigen decreased antibody response and increased nonspecific IgG production. Human splenic lymphocytes were stimulated for 6 days with CMV antigen (50 ng/ml) and/or B-cell growth factor (BCGF), and then fused with mouse myeloma cells. Stimulation with a combination of antigen and BCGF were able to generate CMV-specific hybridomas synergistically. Two of these hybridomas were cloned by limiting dilution. The human monoclonal antibodies produced by them, C1 and C23, bound to CMV but not to other herpesviruses. C23 neutralized virus infectivity C1 did not at all. This method for generation of hybridomas producing human monoclonal antibodies against a predefined antigen may be applicable to a variety of viral antigens.

Antibodies, Monoclonal↗
PubMed1986

Generation of hybridomas producing human monoclonal antibodies against herpes simplex virus after in vitro stimulation.

Hybridomas producing human monoclonal antibodies against herpes simplex virus were generated by in vitro antigen stimulation before cell fusion. The cell fusion with tonsillar lymphocytes which were stimulated with antigen and/or pokeweed mitogen generated many hybridomas producing human IgG against the virus. A combination of antigen and pokeweed mitogen synergistically enhanced the generation of virus-specific hybridomas. Furthermore, the higher the antibody response of the tonsil, the more virus-specific hybridomas were generated by the cell fusion. These results suggest that cell fusion with in vitro stimulated lymphocytes can be applied to a variety of clinically relevant viruses.

Animals↗
PubMed1986

Hormonal effects and the control of gluconeogenesis from sorbitol, xylitol and glycerol in perfused chicken liver.

Addition of sorbitol or xylitol to perfused chicken liver caused a biphasic increase in the rate of glucose production. The second increase correlated with a decrease in the lactate to pyruvate ratio. Increased glucose production in response to the addition of glycerol was not biphasic. Aminooxyacetate inhibited both the inherent second increase in glucose production and stimulatory effects of alanine and pyruvate. The stimulatory effects of norepinephrine and glucagon on gluconeogenesis from sorbitol decreased in the presence of methylene blue. Only the stimulatory effect of norepinephrine was inhibited by aminooxyacetate.

Aminooxyacetic Acid↗
PubMed1986

Microinjection of partially purified protein factor restores DNA damage specifically in group A of xeroderma pigmentosum cells.

Microinjection of cell extracts prepared from both human placenta and HeLa cells into xeroderma pigmentosum (XP) cells of complementation group A restores unscheduled DNA synthesis (UDS) in these cells after UV irradiation [de Jonge, A., Vermeulen, W., Klein, B. & Hoeijmakers, J. (1983) EMBO J. 2, 637-641]. These cells also showed normal resistance to UV irradiation. The half-life of the factors in the cell extracts corresponding to the UDS activity (factor A) was 14 hr in XP cells of group A, and the maximal level of UDS was exerted 2 hr after microinjection. The factors were sensitive to protease treatment but not to RNase treatment and were found to be approximately equal to 160 and approximately equal to 90 kDa by gel filtration. These two fractions of the factor(s) acted specifically in XP cells of complementation group A among complementation groups A, B, C, D, F, G, and probably E and H.

DNA Repair↗
PubMed1986

Characteristics of rat hindlimbs perfused with erythrocyte- and albumin-free medium.

The isolated rat hindlimb was perfused with Krebs-bicarbonate buffer without erythrocytes and albumin in a flow-through mode at 32 degrees C, and the viability and metabolic characteristics of perfused skeletal muscle were examined. 1) With the flow rate at 15 ml X min-1 X leg-1, glucose and O2 uptake, lactate release, lactate-to-pyruvate ratio in effluent, and tissue creatine phosphate and adenine nucleotides remained constant at rest during perfusion for 90 min. The twitch tension changed little over perfusion. 2) When the leg was stimulated at a frequency below 0.5 Hz, the standard flow rate adequately delivered O2 to the perfused leg. Sciatic nerve stimulation enhanced glucose uptake in the absence of insulin. 3) The stimulatory effect of insulin on glucose uptake was observed with a concentration as low as 0.1 mU/ml, and maximal effect was at approximately mU/ml, with a nearly eightfold increase in glucose uptake. 4) Epinephrine and isoproterenol at a concentration of 0.5 nM stimulated lactate release, with maximal effect at 5 nM. The response to catecholamines was reversible and reproducible with a single preparation during the perfusion period of 120 min. The results indicated that the perfusion of hindlimb with a hemoglobin- and albumin-free medium is a convenient and reliable tool for the biochemical investigations of the integral function of hindlimb skeletal muscle.

Adenine Nucleotides↗