Biomedical subjects

Nobuhiro Suzuki

Publications and source records attributed to Nobuhiro Suzuki.

40 records · Page 3Linked to original sources

PubMed2002

T-226296: a novel, orally active and selective melanin-concentrating hormone receptor antagonist.

Through the screening of our in-house chemical compound library, we found a novel melanin-concentrating hormone (MCH) receptor antagonist, T-226296, a (-) enantiomer of N-[6-(dimethylamino)-methyl]-5,6,7,8-tetrahydro-2-naphthalenyl]-4'-fluoro[1,1'-biphenyl]-4-carboxamide. T-226296 exhibited high affinity for cloned human and rat MCH receptors (SLC-1) in receptor binding assays (IC50=5.5+/-0.12 nM for human SLC-1; 8.6+/-0.32 nM for rat SLC-1). T-226296 had high selectivity over other receptors, including the second subtype of the MCH receptor, SLT (MCH2), transporters and ion channels. In Chinese hamster ovary (CHO) cells expressing human SLC-1, T-226296 reversed the MCH-mediated inhibition of forskolin-stimulated cAMP accumulation, inhibited MCH-induced intracellular Ca2+ increase, and also inhibited MCH-stimulated arachidonic acid release. In rats, oral administration of T-226296 (30 mg/kg) almost completely suppressed the food intake induced by intracerebroventricular injection of MCH. These results clearly indicate that T-226296 is a novel, orally active and selective MCH receptor antagonist that will be promising for further exploring the physiology and pathophysiology of MCH-SLC-1 signaling.

Administration, Oral↗

PubMed2002

Low plasma levels of hemostatic proteins during the induction phase in children with acute lymphoblastic leukemia: A retrospective study by the JACLS. Japan Association of Childhood Leukemia Study.

BACKGROUND: Thromboembolic and bleeding events are serious complications associated with the administration of L-asparaginase (ASP) during the induction phase in children with acute lymphoblastic leukemia (ALL). Prophylactic supplementation of plasma-derived coagulation products remains controversial. The purposes of this study were to examine the plasma levels of hemostatic proteins during the induction phase and the efficacy of prophylactic replacement of plasma-derived products. METHODS: A multicenter retrospective survey on the incidence of hemostatic complications and the frequency of prophylactic replacement of plasma-derived products among children with ALL who under went ASP therapy was conducted. All patients were treated according to the Japan Association of Childhood Leukemia Study (JACLS) ALL-97 protocol. RESULTS: Thirty-six (67%) of the 54 JACLS-treatment centers responded and provided information on 127 patients. Clinically relevant hemostatic complications occurred in two patients (1.6%;2/127); one patient suffered intracranial bleeding 5 days after beginning the protocol, and the second patient suffered an ischemic attack during an ASP treatment. The administration of ASP(10 000 u/m2 x six doses) led to significant reductions in the plasma fibrinogen (180 +/- 74 to 105 +/- 57 mg/dL),antithrombin III (AT III) (126 +/- 21 to 73 +/- 18%),and plasminogen levels (97 +/- 17 to 52 +/- 18%). These laboratory parameters returned to normal levels 2 weeks after completion of the ASP treatment. Forty-eight patients (38%)received AT III concentrate (AT III-supplement group). The AT III level of the AT III-supplement group was significantly lower than that of the AT III non-supplement group, not only during the ASP therapy, but also prior to the ASP therapy. A greater percentage of patients in the AT III-supplement group received fresh-frozen plasma and in greater amounts than those in the AT III non-supplement group. CONCLUSIONS: Severe hemorrhage and thrombosis were uncommon in the ALL patients who underwent ASP therapy in comparison with the degree of coagulation changes. Prophylactic administration of AT III concentrate or fresh-frozen plasma did not demonstrate clear beneficial effects in the treatment of ALL in preventing thromboembolic events.

Antineoplastic Agents↗

PubMed2002

Extending chestnut blight hypovirus host range within diaporthales by biolistic delivery of viral cDNA.

Biolistic bombardment was used to successfully transform three phytopathogenic fungal species with an infectious cDNA clone of the prototypic hypovirus, CHV1-EP713, a genetic element responsible for the virulence attenuation (hypovirulence) of the chestnut blight fungus, Cryphonectria parasitica. The fungal species included two strains each of C. parasitica and Valsa ceratosperma, as well as one strain of Phomopsis G-type (teleomorph Diaporthe Nitschke); all are members of the order Diaporthales but classified into three different genera. A subset of transformants for each of the fungal species contained CHV1-EP713 dsRNA derived from chromosomally integrated viral cDNA. As has been reported for CHV1-EP713 infection of the natural host C parasitica, biolistic introduction of CHV1-EP713 into the new fungal hosts V ceratosperma and Phomopsis G-type resulted in altered colony morphology and, more importantly, reduced virulence. These results suggest a potential for hypoviruses as biological control agents in plant-infecting fungal pathogens other than the chestnut blight fungus and closely related species. In addition, the particle delivery technique offers a convenient means of transmitting hypoviruses to potential host fungi that provides new avenues for fundamental mycovirus research and may have practical applications for conferring hypovirulence directly on infected plants in the field.

Ascomycota↗

PubMed2002

Contribution of protein p40 to hypovirus-mediated modulation of fungal host phenotype and viral RNA accumulation.

The papain-like protease p29, derived from the N-terminal portion of the hypovirus CHV1-EP713-encoded open reading frame (ORF) A polyprotein, p69, was previously shown to contribute to reduced pigmentation and sporulation by the infected host, the chestnut blight fungus Cryphonectria parasitica, while being dispensable for virus replication and attenuation of fungal virulence (hypovirulence). We now report that deletion of the C-terminal portion of p69, which encodes the highly basic protein p40, resulted in replication-competent mutant viruses that were, however, significantly reduced in RNA accumulation. While the Delta p40 mutants retained the ability to confer hypovirulence, Delta p40-infected fungal strains produced more asexual spores than strains infected with either wild-type CHV1-EP713 or a Delta p29 mutant virus. As observed for Delta p29-infected colonies, pigment production was significantly increased in Delta p40-infected fungal strains relative to that in CHV1-EP713-infected strains. Virus-mediated suppression of laccase production was not affected by p40 deletion. A gain-of-function analysis was employed to map the p40 symptom determinant to the N-terminal domain, encompassing p69 amino acid residues Thr(288) to Arg(312). Evidence that the gain of function was due to the encoded protein rather than the corresponding RNA sequence element was provided by introducing frameshift mutations on either side of the activity determinant domain. Moreover, restoration of symptoms correlated with increased accumulation of viral RNA. These results suggest that p40 indirectly contributes to virus-mediated suppression of fungal pigmentation and conidiation by providing an accessory function in hypovirus RNA amplification. A possible role for p40 in facilitating ORF B expression and the relationship between hypovirus RNA accumulation and symptom expression are discussed.

Amino Acid Sequence↗