Biomedical subjects

Y Toyoda

Publications and source records attributed to Y Toyoda.

At least 37 records · Page 2Linked to original sources

PubMed2001

Cord blood transplantation from HLA-mismatched unrelated donors as a treatment for children with haematological malignancies.

Factors influencing the outcome for 39 children with haematological malignancy who were subjected to a cord blood transplantation (CBT) from genotypically HLA-mismatched unrelated donors were analysed. This retrospective study included 21 children with acute lymphoblastic leukaemia, 15 with acute myelogenous leukaemia and one each with chronic myelogenous leukaemia, refractory anaemia with myelodysplastic syndrome (MDS) and juvenile myelomonocytic leukaemia (JMML). Those subjected to CBT during the first or second complete remission (CR) and MDS without blasts were assigned to the standard-risk (SR) group (n = 16). Patients in third or subsequent remission, relapse or partial remission with refractory leukaemia at the time of CBT were considered to be in advanced phase, and placed in the high-risk (HR) group (n = 11). JMML and the second CR after a relapse (n = 8), or bone marrow failure after a rejection (n = 3), following haematopoietic stem cell transplantation (HSCT) in the first CR were included in the high-risk group. Kaplan-Meier estimates for neutrophil and platelet recovery were 83.7 +/- 12.2 at d 60 and 55.4 +/- 16.6% at d 100 respectively. The incidence of grades II-VI acute graft-versus-host disease was 58.5 +/- 16.8%. The Kaplan-Meier estimate for 3-year event-free survival (EFS) was 49.2 +/- 16.6. From multivariate analysis, the most important factor influencing EFS was disease status at CBT: SR patients had a 3-year EFS of 75.0 +/- 21.6%, compared with 29.6 +/- 20.6% for those with HR disease (P = 0.013, RR 4.746, 95% CI 1.382-16.298). These data confirm that HLA-mismatched, unrelated CBT is a feasible procedure to cure a significant proportion of children with leukaemia, especially if conducted in a favourable phase of the disease.

Adolescent↗

PubMed2001

Pigmented intraosseous odontogenic carcinoma of the maxilla: a pediatric case report and differential diagnosis.

We report a pigmented intraosseous odontogenic carcinoma of the maxilla occurring in a 6-year-old Japanese boy. Grossly, the tumor showed solid, gray-yellow, and markedly pigmented appearance. Histology showed neoplastic growths of atypical epithelial cells that occasionally contained melanin pigments. Melanocytes with dendritic processes were often found in the tumor cell clusters, and solitary or aggregated melanophages were scattered within the dense fibrovascular stroma. The tumor cells were diffusely positive for cytokeratins and epithelial membrane antigen, and focally positive for vimentin, neuron specific enolase, neurofilament protein, carcinoembryonic antigen, and amelogenin. Ultrastructural studies showed well-developed intercellular junctions, mainly desmosomes, and glycogen particles. In addition, some tumor cells contained melanosomes and/or a few neurosecretory granules. We consider that the present tumor suggests a close association of ectoderm, mesenchyma, and neuroectoderm in embryogenesis of the tooth, and can raise a diagnostic confusion with melanotic neuroectodermal tumor.

Antigens, Neoplasm↗

PubMed2001

Ewing's sarcoma family of tumor arising in the adrenal gland--possible diagnostic pitfall in pediatric pathology: histologic, immunohistochemical, ultrastructural, and molecular study.

We present an adrenal Ewing's sarcoma family of tumor (ESFT) arising in an 11-year-old Japanese boy. Although intensive chemoradiotherapy and radical surgery were performed, the patient died of obstinate disease 1 year and 3 months after the initial presentation. The primary site (adrenal gland) with radiologic findings (with foci of calcification), high titer of serum neuron specific enolase, and sheets of monotonous primitive rounded cells on histology mostly favored neuroblastoma. However, a diagnosis of ESFT was confirmed by immunohistochemical profile, including MIC2-positivity and molecular study disclosing EWS-FLI1 chimera gene verified by direct sequencing. Recognition of adrenal ESFT and use of newly developed diagnostic techniques are required for differential diagnosis of undifferentiated small round cell tumor of the adrenal gland.

12E7 Antigen↗

PubMed2001

Late recurrence of neuroblastoma stage 4S with unusual clinicopathologic findings.

The authors present unusual clinicopathologic findings of a patient with neuroblastoma stage 4S that recurred 11 years after induction of complete remission with chemotherapy. A 12-year-old girl presented with recurrent tumor in the liver. Urinary catecholamine metabolites were within normal range in contrast to the increased values at initial presentation. She underwent left lateral segmentectomy and biopsy of the right lobe. Histologic analysis of the recurrent tumor showed undifferentiated neuroblastoma intermingled with mature ganglioneuromatous lesions. There also were scattered ganglioneuromatous lesions throughout nontumorous area of the liver. Although multimodal intensified treatments including autologous bone marrow transplantation were performed, the patient died of obstinate recurrent tumor at age 14 years. The clinicopathologic findings suggested dedifferentiation from the ganglioneuromatous lesion rather than ordinary recurrence of the primary tumor. The current case and the literature review may indicate that long-term follow-up would be necessary for neuroblastoma stage 4/4S cases. J Pediatr Surg 36:953-955.

Child↗

PubMed2001

Regulation of hepatic glucose metabolism by translocation of glucokinase between the nucleus and the cytoplasm in hepatocytes.

We studied the role of glucokinase translocation between the nucleus and the cytoplasm in hepatocytes. In cultured hepatocytes, both the translocation of glucokinase from the nucleus to the cytoplasm and the rate of glucose phosphorylation were increased when cells were incubated with high concentrations of glucose. The addition of low concentrations of fructose, which is known to stimulate glucose phosphorylation, stimulated both glucokinase translocation and glucose phosphorylation. There was a good correlation between the increase in cytoplasmic glucokinase induced by fructose and that in the glucose phosphorylation rate induced by fructose. Furthermore, we observed a linear relationship between cytoplasmic glucokinase activity and rate of glucose phosphorylation over various glucose concentrations in the absence or presence of fructose. These results indicate that glucose phosphorylation in hepatocytes depended on glucokinase in the cytoplasmic compartment--that is, the increase in the rate of glucose phosphorylation was due to the increase in translocation of glucokinase out of the nucleus. Also, oral administration of glucose, fructose, or glucose plus fructose to 24-h fasted rats induced translocation of glucokinase in the liver. All of these results indicate that hepatic glucose metabolism is regulated by the translocation of glucokinase.

Administration, Oral↗

PubMed2001

In vivo ESR study on hepatic reduction of a nitroxide radical after administration of glucose in rats.

The in vivo reducing ability of a nitroxide radical, 4-hydroxyl-2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPOL), in the liver of rats was estimated by using an electron spin resonance spectrometer equipped with a surface-coil-type resonator following administration of glucose. Both oral and intravenous administration of glucose significantly enhanced the reduction capacity. In vitro studies show that the reduction site of TEMPOL in the hepatic homogenate is located in the mitochondrial respiratory chain and microsomal electron transport system. These findings indicate that the enhancement of activity of these systems caused by the glucose administration prompts reduction of TEMPOL in the liver.

Animals↗

PubMed2001

Respiratory and cardiovascular effects of WP-934 in guinea pigs.

WP-934 is a newly developed reversible thermo-setting in situ gelling ophthalmic solution containing timolol. We investigated the effects of WP-934 on the respiratory and cardiovascular systems in guinea pigs and compared them with those of the conventional ophthalmic solution of timolol. At 30 min after instillation of timolol 0.5%, the airway responsiveness to histamine was 4 times higher, and that to acetylcholine was 2.5 times higher, than that before instillation. At 30 min after instillation of WP-934 0.5%, in contrast, the increase in responsiveness to each drug was about half that seen with the conventional solution. Topical instillation of timolol 0.5% weakened the effects of salbutamol and aminophylline on bronchodilatation, while that of WP-934 0.5% had no effect on aminophylline-induced bronchodilatation and a weaker effect on salbutamol-induced bronchodilatation. Topical instillation of timolol 0.5% and WP-934 0.5% failed to show a significant effect on blood pressure but caused a 10 to 20% decrease in heart rate for at least 120 min after instillation. WP-934 appears to have less respiratory adverse effects than timolol, mainly due to its longer retention on the ocular surface and a consequent decrease in systemic absorption.

Acetylcholine↗

PubMed2001

The use of intravenous nitroglycerin in a case of spasm of the sphincter of Oddi during laparoscopic cholecystectomy.

Spasm of the sphincter of Oddi still occurs during cholecystectomy. Some reports indicate that the spasm, induced by morphine, can be reversed by injection of naloxone, nalbuphine, and glucagon. Others maintain that nitroglycerin or nifedipine can relax the sphincter of Oddi muscle. We recently encountered spasm of the sphincter of Oddi during a laparoscopic cholecystectomy and treated it successfully with intravenous nitroglycerin.

Cholecystectomy, Laparoscopic↗

PubMed2001

In vitro and in vivo antibacterial activities of TAK-083, an agent for treatment of Helicobacter pylori infection.

The antibacterial activity of TAK-083 was tested against 54 clinical isolates of Helicobacter pylori and was compared with those of amoxicillin, clarithromycin, and metronidazole. The growth-inhibitory activity of TAK-083 was more potent than that of amoxicillin, clarithromycin, or metronidazole (the MICs at which 90% of the strains are inhibited were 0.031, 0.125, 64, and 8 microg/ml, respectively). The antibacterial activity of TAK-083 was highly selective against H. pylori; there was a >30-fold difference between the concentration of TAK-083 required to inhibit the growth of H. pylori and that required to inhibit the growth of common aerobic and anaerobic bacteria. Exposure of H. pylori strains to TAK-083 at the MIC or at a greater concentration resulted in an extensive loss of viability. When four H. pylori strains were successively subcultured in the medium containing subinhibitory concentrations of TAK-083, no significant change in the MICs of this compound was observed. TAK-083 strongly inhibited the formation of tryptophanyl-tRNA in H. pylori while exhibiting little effect on the same system in eukaryotes. TAK-083 was efficacious in the treatment of gastric infection caused by H. pylori in Mongolian gerbils. The results presented here indicate that TAK-083 is a promising candidate for the treatment of H. pylori infection.

Amoxicillin↗

PubMed2001

Expression of Babesia equi merozoite antigen 1 in insect cells by recombinant baculovirus and evaluation of its diagnostic potential in an enzyme-linked immunosorbent assay.

The gene encoding the entire Babesia equi merozoite antigen 1 (EMA-1) was inserted into a baculovirus transfer vector, and a recombinant virus expressing EMA-1 was isolated. The expressed EMA-1 was transported to the surface of infected insect cells, as judged by an indirect fluorescent-antibody test (IFAT). The expressed EMA-1 was also secreted into the supernatant of a cell culture infected with recombinant baculovirus. Both intracellular and extracellular EMA-1 reacted with a specific antibody in Western blots. The expressed EMA-1 had an apparent molecular mass of 34 kDa that was identical to that of native EMA-1. The secreted EMA-1 was used as an antigen in an enzyme-linked immunosorbent assay (ELISA). The ELISA differentiated B. equi-infected horse sera from Babesia caballi-infected horse sera or normal horse sera. The ELISA was more sensitive than the complement fixation test and IFAT. These results demonstrated that the recombinant EMA-1 expressed in insect cells might be a useful diagnostic reagent for detection of antibodies to B. equi.

Animals↗

PubMed2001

Adenosine-enhanced ischemic preconditioning: adenosine receptor involvement during ischemia and reperfusion.

Adenosine-enhanced ischemic preconditioning (APC) extends the cardioprotection of ischemic preconditioning (IPC) by both significantly decreasing myocardial infarct size and significantly enhancing postischemic functional recovery. In this study, the role of adenosine receptors during ischemia-reperfusion was determined. Rabbit hearts (n = 92) were used for Langendorff perfusion. Control hearts were perfused for 180 min, global ischemia hearts received 30-min ischemia and 120-min reperfusion, and IPC hearts received 5-min ischemia and 5-min reperfusion before ischemia. APC hearts received a bolus injection of adenosine coincident with IPC. Adenosine receptor (A(1), A(2), and A(3)) antagonists were used with APC before ischemia and/or during reperfusion. GR-69019X (A(1)/A(3)) and MRS-1191/MRS-1220 (A(3)) significantly increased infarct size in APC hearts when administered before ischemia and significantly decreased functional recovery when administered during both ischemia and reperfusion (P < 0.05 vs. APC). DPCPX (A(1)) administered either before ischemia and/or during reperfusion had no effect on APC cardioprotection. APC-enhanced infarct size reduction is modulated by adenosine receptors primarily during ischemia, whereas APC-enhanced postischemic functional recovery is modulated by adenosine receptors during both ischemia and reperfusion.

Adenosine↗

PubMed2001

Cryopreservation and transport of mouse spermatozoa at -79 degrees C.

In the present study, 2 experiments were carried out. In experiment 1, mouse spermatozoa were frozen and stored in an ultra-low temperature freezer maintained at -79 degrees C, from 1 week to 8 months. In vitro fertilization rates of the frozen-thawed sperm after 1 week and 4 months of storage were high at 71 and 71%, respectively. These values did not differ significantly from the value (73%) of the control stored at -196 degrees C. In contrast, the 8-month storage rate was significantly lower at 51%. In experiment 2, frozen spermatozoa were transported in a Styrofoam box packed in dry ice from Hokkaido to Tokyo. In vitro fertilization rate of frozen-thawed sperm after transport at -79 degrees C was high at 88%, which was not significantly different from that (84%) of the transported control at -190 degrees C. After transferring two-cell embryos derived from frozen spermatozoa to recipients, 37-62% of the embryos developed into offspring in both experiments. These results indicate that mouse spermatozoa can survive cryopreservation in an ultra-low temperature freezer (-79 degrees C) for up to 4 months and transport at -79 degrees C.

Animals↗

PubMed2000

Targeted disruption of Na+/Ca2+ exchanger gene leads to cardiomyocyte apoptosis and defects in heartbeat.

Ca(2+), which enters cardiac myocytes through voltage-dependent Ca(2+) channels during excitation, is extruded from myocytes primarily by the Na(+)/Ca(2+) exchanger (NCX1) during relaxation. The increase in intracellular Ca(2+) concentration in myocytes by digitalis treatment and after ischemia/reperfusion is also thought to result from the reverse mode of the Na(+)/Ca(2+) exchange mechanism. However, the precise roles of the NCX1 are still unclear because of the lack of its specific inhibitors. We generated Ncx1-deficient mice by gene targeting to determine the in vivo function of the exchanger. Homozygous Ncx1-deficient mice died between embryonic days 9 and 10. Their hearts did not beat, and cardiac myocytes showed apoptosis. No forward mode or reverse mode of the Na(+)/Ca(2+) exchange activity was detected in null mutant hearts. The Na(+)-dependent Ca(2+) exchange activity as well as protein content of NCX1 were decreased by approximately 50% in the heart, kidney, aorta, and smooth muscle cells of the heterozygous mice, and tension development of the aortic ring in Na(+)-free solution was markedly impaired in heterozygous mice. These findings suggest that NCX1 is required for heartbeats and survival of cardiac myocytes in embryos and plays critical roles in Na(+)-dependent Ca(2+) handling in the heart and aorta.

Animals↗

PubMed2000

A novel glucokinase regulator in pancreatic beta cells: precursor of propionyl-CoA carboxylase beta subunit interacts with glucokinase and augments its activity.

A glucokinase regulatory protein has been reported to exist in the liver, which suppresses enzyme activity in a complex with fructose 6-phosphate, whereas no corresponding protein has been found in pancreatic beta cells. To search for such a protein in pancreatic beta cells, we screened for a cDNA library of the HIT-T15 cell line with the cDNA of glucokinase from rat islet by the yeast two hybrid system. We detected a cDNA encoding the precursor of propionyl-CoA carboxylase beta subunit (pbetaPCCase), and glutathione S-transferase pull-down assay illustrated that pbetaPCCase interacted with recombinant rat islet glucokinase and with glucokinase in rat liver and islet extracts. Functional analysis indicated that pbetaPCCase decreased the K(m) value of recombinant islet glucokinase for glucose by 18% and increased V(max) value by 23%. We concluded that pbetaPCCase might be a novel activator of glucokinase in pancreatic beta cells.

Animals↗

PubMed2000

Anti-stunning and anti-infarct effects of adenosine-enhanced ischemic preconditioning.

BACKGROUND: Adenosine-enhanced ischemic preconditioning (APC) extends the protection afforded by ischemic preconditioning (IPC) by both significantly decreasing infarct size and significantly enhancing post-ischemic functional recovery. In this study, the anti-infarct effects and the anti-stunning effects of APC in contributing to enhanced post-ischemic functional recovery were determined and compared with IPC. METHODS AND RESULTS: Sheep (n=96) were subjected to 15, 30, 45, or 60 minutes of regional ischemia and 120 minutes of reperfusion. IPC hearts received 5 minutes of regional ischemia and 5 minutes of reperfusion before ischemia/reperfusion. APC hearts received a bolus injection of adenosine coincident with IPC. Adenosine hearts (ADO) received a bolus injection of adenosine before ischemia/reperfusion. Regional ischemia (RI) hearts received no pretreatment. Infarct size/area at risk was determined by tetrazolium staining. Regional myocardial function was determined by sonomicrometry. Segment shortening after 15 minutes of ischemia in which no infarct was incurred was 32. 1+/-10.6% in RI, 70.6+/-8.5% in IPC, and 77.4+/-6.0% in APC hearts. Segment shortening after 30 minutes of ischemia was 60.7+/-6.3% in APC hearts (P:<0.05 versus RI, ADO, IPC) but was <37% in all other groups. Infarct size/area at risk after 30 and 60 minutes of ischemia was, respectively, 25.8+/-5.7% and 49.8+/-6.0% in RI, 12. 9+/-3.0% and 29.2+/-5.0% in ADO, 11.6+/-2.4% and 24.6+/-2.7% in IPC, and 5.1+/-1.6% and 12.4+/-2.0% in APC hearts (P:<0.05 versus RI, ADO, IPC). CONCLUSIONS: APC and IPC exhibit anti-infarct and anti-stunning effects in the ovine heart, but these effects are rapidly diminished with IPC. APC significantly extends these effects, providing for significantly enhanced infarct size reduction and post-ischemic functional recovery (P:<0.05 versus IPC).

Adenosine↗

PubMed2000

Isolation and characterization of a novel liver-specific gene, hepassocin, upregulated during liver regeneration.

By differential cDNA cloning coupled with Xenopus oocyte expression screening, we isolated a cDNA encoding a novel protein, termed 'hepassocin', the expression of which is upregulated in the regenerating rat liver. The cDNA contained a single open reading frame encoding a protein of 314 amino acids (ca. 34 kDa), including 24 amino acids of signal sequence. The protein expressed from the cDNA in Verots cells had activity to stimulate DNA synthesis in primary rat hepatocytes and was of 66 kDa or 34 kDa, under non-reducing or reducing conditions, respectively. Using an affinity column conjugated with the antibody raised against a peptide in a hydrophilic region, we purified hepassocin from the rat liver: it had a DNA synthesis-stimulating activity in hepatocytes. The hepassocin obtained here was 66 kDa, and the 34 kDa protein obtained under reducing conditions contained five cysteine residues, indicating that hepassocin is active as a homodimer. Northern blot analysis revealed that hepassocin mRNA (1.4 kb in length) occurred only in the liver, and in situ hybridization studies revealed its presence in parenchymal hepatocytes but not in endothelial cells. Furthermore, the expression of hepassocin mRNA was upregulated during compensatory hyperplasia after partial hepatectomy and regeneration after galactosamine treatment in the rat liver. These results suggest that hepassocin plays an important role in stimulating liver cell growth, through an autocrine mechanism.

Amino Acid Sequence↗

PubMed2000

Analysis of the role of egg integrins in sperm-egg binding and fusion.

Sperm-egg fusion is believed to be mediated via specific molecular interactions. Integrin alpha6beta1 is a strong candidate for a sperm receptor on the egg plasma membrane. However, the ability of the egg integrin alpha6beta1 to interact with molecules on intact sperm has not yet been proven. In this report, possible involvement of integrin alpha6beta1 in sperm-egg interactions was examined by biochemical and immunocytochemical analyses. To identify egg molecules that specifically interact with sperm, we first incubated sperm with biotin-labeled egg surface proteins. Under this condition, solubilized proteins from eggs inhibited sperm-egg fusion. Western blot analysis under reducing conditions indicated that a major-labeled band of 135 kDa bound to sperm. An immunodepletion experiment using the anti-integrin alpha6 antibody GoH3 indicated that the 135 kDa egg surface molecule that bound to sperm was the integrin alpha6 subunit. To investigate the potential involvement of integrin alpha6beta1 in sperm-egg fusion, we next examined the localization of integrin alpha6 and beta1 subunits before and after fertilization by confocal laser microscopy. At an early stage of sperm-egg fusion, the integrin alpha6 and beta1 subunits were accumulated at the sperm binding site. The frequency of cluster formation was closely related to that of sperm-egg fusion, indicating that integrin receptors are accumulated by sperm destined for fusion. Taken together, these results strongly suggest that the integrin alpha6beta1 is involved in sperm-egg binding leading to fusion via direct association of the integrin alpha6 with sperm.

Animals↗

PubMed2000

Expression of SAG-1 of Toxoplasma gondii in transgenic mice.

We describe the expression of SAG-1 cDNA in B6C3F1 mice by microinjecting a 3.3 kbp DNA fragment, consisting of the cytomegalovirus enhancer-chicken beta-actin hybrid promoter and SAG-1 into the pronucleus of a fertilized egg at the one-cell stage. Offspring derived from this microinjection were analyzed for the integration and functional expression of the SAG-1 transgene. Steady-state expressions of both the mRNA for SAG-1 and SAG-1 protein product were detected in the brain, thymus, spleen and liver. Approximately 50% of F1 and F2 progeny inherited the SAG-1 transgene from SAG-1 transgenic mice in Mendelian fashion. These results indicated that SAG-1 transgenic lines were established. Transgenic mice harboring the SAG-1 gene will contribute a critical tool of defining the molecular mechanisms of SAG-1 in pathogenesis and host immune response.

3T3 Cells↗