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Biomedical subjects

Toshio Suzuki

Publications and source records attributed to Toshio Suzuki.

At least 55 records · Page 3Linked to original sources
PubMed2003

Development and preventative effect against pine wilt disease of a novel liquid formulation of emamectin benzoate.

Injection of the poorly water-soluble emamectin benzoate (EB) into pine trunks required the development of an efficient liquid formulation. For injection into big trees in forests a good rate of injection and a high active content were required. Tests on the viscosity and EB-solubilizing ability of 14 various solubilizers in diethylene glycol monobutyl ether (DGMBE) led to the selection of Sorpol SM-100PM as the solubilizer of the formulation. Relationships between the solubilizing ability and amounts of Sorpol SM-100PM and DGMBE relative to that of EB, and between the concentration of the latter and the viscosity or the injection rate of the formulation led to a novel 40 g litre(-1) emamectin benzoate formulation (Shot Wan Liquid Formulation), which was composed of EB (40), Sorpol SM-100PM (120), DGMBE (160) and distilled water (50 g litre(-1)) in methanol. Injection of this formulation at a dose of 10 g EB per unit volume of pine tree prevented over 90% of the trees from wilting caused by pine wood nematode, and this preventative effect continued for 3 years. Neither discolouration of the leaves nor injury around the injection hole on the trees was observed after injection of the formulation.

Animals↗
PubMed2003

Characterization of 11-dehydro-thromboxane B2 recombinant antibody obtained by phage display technology.

Recombinant monoclonal antibodies specific for 11-dehydro-thromboxane B(2) (11D-TX) were isolated from the combinatorial libraries on a pComb3 phage-display vector using a magnetic cell sorting (MACS) system. The libraries were constructed from repertories of light and heavy-chains derived from the total RNA of 11D-TX conjugated keyhole limpet haemocyanin-immunized mice. Biotinylation of 11D-TX conjugated bovine serum albumin (BSA) was performed through free thiol groups on BSA using 1-biotinamido-4-[4'-(maleimidomethyl) cyclohexanecarboxamido] butane (Biotin-BMCC). Affinity bio-panning was performed to enrich the phage display libraries against biotinylated 11D-TX conjugated BSA with the MACS system. Results indicated that the selected anti-11D-TX Fab fragments expressed by E. coli exhibited a five-fold higher affinity for BSA conjugated 11D-TX compared to BSA alone and little specificity to other related compounds as determined by the binding assay and inhibition enzyme-linked immunosorbent assay (ELISA). This is the first report of an antibody against prostaglandin produced by phage display technology and also determination of the DNA sequence of this antibody. The MACS system was shown to be a simpler and more efficient method of panning than the conventional ELISA procedure. According to our results, we concluded that the phage display technique combined with the MACS system allowed the selection of the antibody with high affinity and some specificity.

Amino Acid Sequence↗
PubMed2003

Molecular structural and functional characterization of tumor suppressive anti-ErbB-2 monoclonal antibody by phage display system.

To investigate the molecular structural and functional characteristics of tumor-suppressive anti-ErbB-2 monoclonal antibody (mAb) SER4, we performed mAb-gene cloning and epitope mapping by a phage display system. Structural analysis demonstrated that both the heavy chain (HC) and light chain variable regions are highly homologous with the derived germline sequences, while the HC complementarity determining region (HCDR) 3 has a relatively short length and biased amino acid usage. A cloned gene-derived recombinant Fab (rFab) fragment showed antigen binding activity and specificity comparable to the parent mAb. Cross-linking of the rFab fragment with the anti-Fab antibody elicited cell growth inhibition in vitro. These results imply that the cloned genes actually encode the Fab part of SER4. The epitope mimetic peptide (mimotope) isolated by panning a phage-displayed random peptide library against SER4 showed no cross-reactivity with mAbs other than SER4. The mimotope was found to be homologous with (87)AHNQVRQVPLQR(98) in the extracellular domain of ErbB-2 by means of a clustalw search. Since SER4 causes the growth inhibition of ErbB-2 positive cells, the predicted epitope sequence may constitute the putative functional domain of ErbB-2.

Amino Acid Sequence↗
PubMed2003

Monoamine oxidase A gene polymorphism, 5-HT 2A receptor gene polymorphism and incidence of nausea induced by fluvoxamine.

Selective serotonin reuptake inhibitors cause a side effect of nausea with high frequency, but there have been no accurate methods to predict its incidence. The authors first investigated whether a functional polymorphism in the monoamine oxidase A (MAOA-VNTR) and a -1438G/A polymorphism in the promoter region of the 5-HT(2A) gene were associated with the incidence of nausea induced by fluvoxamine. Fluvoxamine was administered for 6 weeks with a specific dosage plan (50-200 mg/day) in 66 Japanese major depressive patients. The frequency of MAOA-VNTR allele 1 was significantly higher in the patients without nausea than in ones with nausea in the statistical analysis including the patients whose plasma levels were below the average and who were considered to be pharmacodynamically more sensitive to nausea. This study showed that the genetic polymorphism of MAOA-VNTR might affect the incidence of nausea induced by SSRIs. If this finding is replicated in other studies with more subjects, MAOA-VNTR polymorphism would be of great clinical use to predict the incidence of nausea induced by SSRIs.

Adult↗
PubMed2003

Chronopharmacokinetics of tacrolimus in kidney transplant recipients: occurrence of acute rejection.

The circadian variation of clinical pharmacokinetics of tacrolimus was studied using 16 adult renal transplant recipients 1 month after the operation. The recipients were administered tacrolimus twice a day (9 a.m. and 9 p.m.), and whole-blood samples were obtained just prior to and 1, 2, 3, 6, 9, and 12 hours after oral administration. Histological specimens of transplant kidney were collected by an allograft core biopsy on day 28 after the transplantation. There were no circadian changes in the area under the concentration-time curve (AUC0-12) (214 ng.h/mL during daytime vs. 223 ng.h/mL during nighttime) resulting from morning and night doses. A slight delay in mean residence time (MRT0-12) and time to the peak concentration (tmax) was found after night doses, but there was no statistical significance. Three patients (18.8%) had a clinical acute rejection (AR) episode 4 to 6 weeks after transplantation, and AUC0-12 at nighttime was significantly lower (18.4% on average) in patients with AR in comparison to those without AR. There was no statistical significance in maximum concentration (Cmax) or morning/night trough levels between patients with and without AR. In regard to the correlation between tacrolimus concentrations in each sampling time and AUC0-12, the morning trough concentrations were less predictable for daytime AUC0-12 (r2 = 0.125), but there was a weak correlation to nighttime AUC0-12 (r2 = 0.424). Tacrolimus concentrations at 2, 3, and 6 hours after the morning dose (C2, C3, and C6) had a good correlation against daytime AUC. The results of this study indicate that the variance on the clinical pharmacokinetics of tacrolimus between daytime and nighttime in renal transplant patients is not significant, while the lower nighttime AUC corresponded to the occurrence of AR.

Adult↗
PubMed2003

Behavior of Medaka fish under distributed gravity.

The threshold value of gravity for Medaka fish (Oryzias latipes) was determined using parabolic flights of an airplane. Rotating a turntable during a 20 sec of microgravity, a gradient field of centrifugal force was realized in the aquarium. Fish of HO5 strain were used because from the previous studies, in microgravity they were known to exhibit looping behavior more easily than any other strains. Looping fish became stable (i.e., recovered their posture control) when fish swam from a lower-gravity area of the aquarium to an area of a certain gravity value or beyond. On the other hand, stable fish lost their posture control and started looping when fish swam into an area of a gravity lower than a certain value. Using these phenomena, we obtained the gravity value of 0.21 to 0.26 G as for the threshold value for Medaka fish to sense the gravity.

Adaptation, Physiological↗
PubMed2002

TNF-related apoptosis-inducing ligand (TRAIL) frequently induces apoptosis in Philadelphia chromosome-positive leukemia cells.

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) and Fas ligand (FasL) have been implicated in antitumor immunity and therapy. In the present study, we investigated the sensitivity of Philadelphia chromosome (Ph1)-positive leukemia cell lines to TRAIL- or FasL-induced cell death to explore the possible contribution of these molecules to immunotherapy against Ph1-positive leukemias. TRAIL, but not FasL, effectively induced apoptotic cell death in most of 5 chronic myelogenous leukemia-derived and 7 acute leukemia-derived Ph1-positive cell lines. The sensitivity to TRAIL was correlated with cell-surface expression of death-inducing receptors DR4 and/or DR5. The TRAIL-induced cell death was caspase-dependent and enhanced by nuclear factor kappa B inhibitors. Moreover, primary leukemia cells from Ph1-positive acute lymphoblastic leukemia patients were also sensitive to TRAIL, but not to FasL, depending on DR4/DR5 expression. Fas-associated death domain protein (FADD) and caspase-8, components of death-inducing signaling complex (DISC), as well as FLIP (FLICE [Fas-associating protein with death domain-like interleukin-1-converting enzyme]/caspase-8 inhibitory protein), a negative regulator of caspase-8, were expressed ubiquitously in Ph1-positive leukemia cell lines irrespective of their differential sensitivities to TRAIL and FasL. Notably, TRAIL could induce cell death in the Ph1-positive leukemia cell lines that were refractory to a BCR-ABL-specific tyrosine kinase inhibitor imatinib mesylate (STI571; Novartis Pharma, Basel, Switzerland). These results suggested the potential utility of recombinant TRAIL as a novel therapeutic agent and the possible contribution of endogenously expressed TRAIL to immunotherapy against Ph1-positive leukemias.

Amino Acid Chloromethyl Ketones↗
PubMed2002

First total syntheses of the phytotoxins solanapyrones D and E via the domino Michael protocol.

The phytotoxins solanapyrones D (1) and E (2) have been synthesized from the decalone prepared by the domino Michael reaction of the kinetic enolate of optically pure acetylcyclohexene with methyl crotonate. The decalone was transformed into a solanapyrone core by equilibration into thermodynamically stable trans-decalone (11), dehydroxylation, and dehydration. Condensation of a methyl acetoacetate equivalent followed by cyclization installed a pyrone moiety. Introduction of a formyl or hydroxymethyl unit into the pyrone ring via Pummerer related reactions furnished solanapyrones D (1) and E (2).

Alternaria↗
PubMed2002

Effects of thymic hormone on reactive oxygen species-scavengers and renal function in tacrolimus-induced nephrotoxicity.

The effects of a thymic hormone (Facteur thymique serique; FTS) on renal reactive oxygen species-scavenging enzymes or substances in heminephrectomized rats with and without tacrolimus-induced nephrotoxicity were studied. Rats received both oral dose of tacrolimus (5 mg/kg/day) and subcutaneous administration of three dosages of FTS (5, 50, and 250 microg/kg/day) over 28 days (Group A). In Group B, they received three dosages of FTS alone (0.5, 5, and 50 microg/kg/day) or FTS 50 microg/kg/day with tacrolimus over 28 days. Each dose of FTS (Group A) partially elevated renal creatinine clearances. Tacrolimus enhanced renal glutathione reductase (GSH-R) activities and glutathione (GSH) and depressed catalase (CAT) activities. FTS increased GSH levels and GSH-R activities. Although FTS alone did not change CAT activities, CAT activities recovered as a result of concomitant use of FTS (Groups A and B). A significant positive correlation was found between CAT activity and creatinine clearance. These findings suggest that FTS is useful for the prevention of tacrolimus-induced nephrotoxicity, and that the increase of renal CAT activity in the defense mechanism of FTS might be important for cell protection against active oxygen species.

Animals↗
PubMed2002

Influence of the serotonin transporter gene-linked polymorphic region on the antidepressant response to fluvoxamine in Japanese depressed patients.

The presence of the long (l) variant of the serotonin (5-hydroxytryptamine: 5-HT) transporter gene-linked polymorphic region (5-HTTLPR) is reported to be associated with a more favorable and faster antidepressant effect of selective serotonin reuptake inhibitors in Caucasians. The frequency of the l allele is lower in Japanese than in Caucasians; therefore, the antidepressant effect of fluvoxamine can be not as good in Japanese as in Caucasians. The authors investigated whether 5-HTTLPR was associated with the antidepressant response to fluvoxamine in 66 Japanese patients with major depressive disorder in a protocolized-dosing 6-week study. The short (s) allele frequency was significantly higher in the responsive individuals than in the nonresponsive ones (P = .010). The present study suggests that fluvoxamine is not less effective in depressive patients carrying the s allele than in the ones carrying the l allele and it is not less effective in Japanese than in Caucasians.

Adult↗
PubMed2002

Monoamine oxidase: A gene polymorphism, tryptophan hydroxylase gene polymorphism and antidepressant response to fluvoxamine in Japanese patients with major depressive disorder.

Monoamine oxidase A (MAOA) and tryptophan hydroxylase (TPH) are the staple enzymes in the metabolism of serotonin (5-HT). The genetic polymorphisms of these two enzymes might individually alter the production, release, reuptake or degradation of 5-HT during the treatment of selective serotonin reuptake inhibitors (SSRIs), leading to the individual differences in the antidepressant effects of SSRIs. The authors investigated whether a functional polymorphism in the MAOA gene promoter (MAOA-VNTR) and a TPH gene polymorphism in intron 7 (TPH-A218C) were associated with the antidepressant response to fluvoxamine in 66 Japanese patients with major depressive disorder during a 6-week study with a specific dosage plan. Fifty-four patients completed the study. The present study fails to demonstrate that the genetic polymorphisms of MAOA-VNTR and TPH-A218C affect the antidepressant effect of fluvoxamine in Japanese patients with major depressive disorder.

Adult↗
PubMed2002

No association between the serotonergic polymorphisms and incidence of nausea induced by fluvoxamine treatment.

We investigated the association between serotonergic polymorphisms and incidence of nausea, which is the most frequent side-effect of selective serotonin reuptake inhibiters (SSRIs), in 66 patients treated with fluvoxamine in a protocolized-dosing method. We focused on three polymorphisms of serotonin (5-HT) neuronal systems such as 5-HT transporter (5-HTT) gene-linked polymorphic region (5-HTTLPR), a variable number of tandem repeat (VNTR) polymorphism in the second intron of the 5-HTT gene (STin2) and tryptophan hydroxylase (TPH) gene polymorphism in intron 7 (TPH-A218C), which have been reported to possess positive association with treatment response to SSRIs. In addition to this, the relationship between development of nausea and treatment response was also analyzed. Results suggested that these three polymorphisms did not affect the development of fluvoxamine-induced nausea, and that incidence of nausea was not a phenomenon that predicts the treatment response to fluvoxamine.

Adult↗
PubMed2002

Design, production, and characterization of recombinant neocarzinostatin apoprotein in Escherichia coli.

Neocarzinostatin (NCS) is the first discovered anti-tumor antibiotic having an enediyne-containing chromophore and an apoprotein with a 1:1 complex. An artificial gene library for NCS apoprotein (apo-NCS) production in Escherichia coli was designed and constructed on a phage-display vector, pJuFo. The recombinant phages expressing pre-apo-NCS protein were enriched with a mouse anti-apo-NCS monoclonal antibody, 1C7D4. The apo-NCS gene (encsA) for E. coli was successfully cloned, and then re-cloned into the pRSET A vector. After the his-tagged apo-NCS protein had been purified and cleaved with enterokinase, the binding properties of the recombinant protein as to ethidium bromide (EtBr) were studied by monitoring of total fluorescence intensity and fluorescence polarization with a BEACON 2000 system and GraphPad Prism software. A dissociation constant of 4.4 +/- 0.3 microM was obtained for recombinant apo-NCS in the fluorescence polarization study. This suggests that fluorescence polarization monitoring with EtBr as a chromophore mimic may be a simplified method for the characterization of recombinant apo-NCS binding to the NCS chromophore. When Phe78 on apo-NCS was substituted with Trp78 by site-directed mutagenesis using a two stage megaprimer polymerase chain reaction, the association of the apo-NCS mutant and EtBr observed on fluorescence polarization analysis was of the same degree as in the case of the wild type, although the calculated maximum change (DeltaIT(max)) in total fluorescence intensity decreased from 113.9 to 31.3. It was suggested that an environmental change of the bound EtBr molecule on F78W might have dramatically occurred as compared with in the case of wild type apo-NCS. This combination of monitoring of fluorescence polarization and total fluorescence intensity will be applicable for determination and prediction of the ligand state bound or associated with the target protein. The histone-specific proteolytic activity was also re-investigated using this recombinant apo-NCS preparation, and calf thymus histone H1, H2A, H2B, H3, and H4. The recombinant apo-NCS does not act as a histone protease because a noticeable difference was not observed between the incubation mixtures with and without apo-NCS under our experimental conditions.

Amino Acid Sequence↗
PubMed2002

Enhanced antitumor effect of ultrasound in the presence of piroxicam in a mouse air pouch model.

The antitumor effects of piroxicam, a non-steroidal anti-inflammatory drug, on sarcoma 180 cells under ultrasonic irradiation were examined in a mouse air pouch model. When piroxicam was added to sarcoma 180 suspension under ultrasound irradiation (2 MHz, 10 W, 120 s), the mortality rate of tumor cells immediately after the irradiation and the survival rate of mice were significantly higher than those when ultrasound alone was applied, and these effects of piroxicam were dose-dependent. When D-mannitol was used with piroxicam, the mortality rate of the tumors cells after the irradiation was comparable with that when piroxicam alone was applied, but when L-histidine was used concurrently, the antitumor effect was significantly lower than that when piroxicam alone was applied. Histological examinations one week after the ultrasound irradiation in the presence of piroxicam showed sparse tumor tissue in the air pouch and normal appearance of the air pouch and surrounding tissue. The findings suggest that piroxicam enhances the anti-tumor effects of ultrasound in vivo by increasing the production of singlet oxygen without damage to tissue surrounding the tumor.

Animals↗
PubMed2002

Association between -1438G/A promoter polymorphism in the 5-HT(2A) receptor gene and fluvoxamine response in Japanese patients with major depressive disorder.

Genetic polymorphism of the serotonin 5-HT(2A) receptor seems to be associated with therapeutic response to selective serotonin reuptake inhibitors (SSRIs). The present study investigated whether a novel -1438G/A polymorphism in the promoter region of the 5-HT(2A )receptor gene is associated with therapeutic response to fluvoxamine (an SSRI) in 66 Japanese patients with major depressive disorder. Fluvoxamine (50 to 200 mg) was administered twice daily for 6 weeks. Fifty-four patients completed this study. The genotype distribution and the allele frequencies showed no significant difference between responders and non-responders. The time-course of the Montgomery-Asberg Depression Rating Scale scores showed no significant difference among -1438G/G, -1438G/A, and -1438A/A genotype groups. The results demonstrated that the -1438G/A promoter polymorphism in the 5-HT(2A) receptor gene was unlikely to have a major role in therapeutic response to fluvoxamine in Japanese patients with major depressive disorder.

Adult↗
PubMed1999

Photoreactions of 4-(Tribromomethyl)-4-methyl-2,5-cyclohexadienone and Its Derivatives with Amines: Radical Cyclization and Ring Expansion Reactions Promoted through Photoinduced Electron Transfer Processes.

Photoreactions of 4-(tribromomethyl)-4-methyl-2,5-cyclohexadienone (1) and its derivatives with amines were studied. Irradiation of 1 with amine produced 4-bromo-5-methyltropone (2) along with 4-(dibromomethyl)-4-methyl-2,5-cyclohexadienone (3). The effects of solvent, added water, and the structural variation in amine on the product ratio were explored. Isolation of the amine-derived products revealed that oxidative dealkylation of amine proceeded during the photoreaction. On the basis of the results obtained, a reaction mechanism involving fragmentation of the dienone anion-radical and amine cation-radical pair is proposed. Photoreactions of dienone 4 with amine produced the tropones 6 and 7, whereas tropone 9 was produced from 8. Trialkyltin radical-induced reductions of dienones 1 and 4 with tri-n-butyltin hydride demonstrated common features with the photoreactions. It was also found that irradiation of dienone 3 with amine produced 4-methyltropone (10).

Journal Article↗
PubMed1996

Synthesis of Optically Active Vasicinone Based on Intramolecular Aza-Wittig Reaction and Asymmetric Oxidation(1).

Both optical isomers of a quinazoline alkaloid, vasicinone, were synthesized by two different methods. The first method used (3S)-3-hydroxy-gamma-lactam as a chiral synthon, which was, after O-TBDMS protection, o-azidobenzoylated followed by treatment with tri-n-butylphosphine to afford (S)-(-)-vasicinone via the tandem Staudinger/intramolecualr aza-Wittig reaction. The second method utilized asymmetric oxygenation of deoxyvasicinone with (1S)-(+)- or (1R)-(-)-(10-camphorsulfonyl)oxaziridine (the Davis reagent), respectively. The aza-enolate anion of deoxyvasicinone was treated with (S)-(+)-reagent to afford (R)-(+)-vasicinone in 71% ee, while the reaction with (R)-(-)-reagent gave (S)-(-)-vasicinone in 62% ee. The optical purity was analyzed by HPLC on specially modified cellulose as a stationary phase. These results provided a facile method to prepare both optical isomers of vasicinone and confirmed the recently reversed stereochemistry of natural (-)-vasicinone.

Journal Article↗