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T Hashida

Publications and source records attributed to T Hashida.

At least 19 recordsLinked to original sources
PubMed2001

Isolation and characterization of the rat prolactin-releasing peptide gene: multiple TATA boxes in the promoter region.

The prolactin-releasing peptide (PrRP) gene is a novel bioactive peptide expressed in very restricted regions in the brain. To explore the molecular mechanism of PrRP gene expression, we cloned and characterized the gene and its promoter region. The gene spans approximately 2.4 kb and contains three exons and two introns. 3'RACE analysis showed that a polyadenylation signal 103 bp downstream from the stop codon was functional. Primer extension analysis indicated three transcriptional start sites (TSSs) 92, 199, and 325 bp upstream from the translational start site. Interestingly, in addition to the putative binding sites for SP1-1, AP-2, and Oct-2A, three characteristic TATA boxes were identified close to these TSSs. Transient transfection study using a series of deletion mutants revealed that the middle TATA box is important for the promoter activity. Furthermore, the cloned 1.6 kb promoter region was active only in neuron- and pituitary-derived cell lines, and the promoter region -1600 approximately -800 bp worked as a negative regulatory element. We demonstrated for the first time, the genomic organization and promoter function of the PrRP gene, and this knowledge will facilitate elucidation of transcriptional control of the PrRP gene.

3' Untranslated Regions↗
PubMed2001

Population pharmacokinetics of tacrolimus in adult recipients receiving living-donor liver transplantation.

OBJECTIVE: To characterize the pharmacokinetics of tacrolimus in adult recipients receiving living-donor liver transplantation (LDLT). METHODS: Thirty-five patients were given tacrolimus as 18- to 60-h intravenous infusions after surgery, followed by a 4-week course of oral dose therapy (at 0900 hours and 2100 hours). Blood samples were collected daily in the morning (0800 hours) beginning the day after surgery. Whole blood concentration data were evaluated by nonlinear mixed-effect modeling using the program NONMEM and were characterized using a one-compartment model. RESULTS: The clearance (CL, l h(-1)) was related to the grafted hepatic weight, postoperative days (POD), and hepatic and renal dysfunction. Interindividual variabilities in CL, volume of distribution (V), and bioavailability (F) were 57.4%. 39.7%, and 63.0%, respectively, and the correlation between individual CL and F was 0.776. Residual intraindividual variability was 2.9 ng ml(-1). Based on the estimated final parameters, a typical recipient of LDLT with grafted hepatic weight of 600 g and normal hepatic and renal function would have a CL of 0.737 l h(-1) on POD 0 and 1.14 l h(-1) on POD 30, V of 1.52 l kg(-1) and F of 6.8%. CONCLUSIONS: Nonlinear mixed-effect modeling was useful for analysis of pharmacokinetic characteristics of tacrolimus in LDLT patients. Immediately after surgery, patients receiving LDLT showed a smaller CL value than other transplant patients, and CL value increased with POD within 30 days after surgery. The estimated population pharmacokinetic parameters can be applied for a priori dosage calculations in adult patients with LDLT.

Adolescent↗
PubMed2001

Pharmacokinetic and prognostic significance of intestinal MDR1 expression in recipients of living-donor liver transplantation.

BACKGROUND: Living-donor liver transplantation (LDLT) and subsequent immunosuppressive therapy with tacrolimus have been cornerstones in the recovery of patients from end-stage liver failure, but there has been no critical dosage regimen for tacrolimus therapy, especially the initial dosage. In this study, we examined whether the absorptive barriers, multidrug resistance protein (MDR1), or cytochrome P450 IIIA4 (CYP3A4) are important pharmacokinetic factors for tacrolimus and are prognostic indicators for LDLT outcome. METHODS: We used competitive polymerase chain reaction to evaluate the messenger ribonucleic acid (mRNA) expression levels of MDRL And Cyp3A4 in mucosal cells of the upper jejunum from a part of the Rroux-en- Y limb for biliary reconstruction during LDLT of recipients (n = 48). The tacrolimus dosage was started at an oral dose of 0.075 mg/kg every 12 hours and adjusted on the basis of its whole-blood trough level by use of a semiautomated microparticle enzyme immunoassay. RESULTS: The mRNA expression level of MDR1 (r = -0.776), but not CYP3A4 (r = -0.094), was inversely related to the concentration/dose ratio of tacrolimus. High levels of MDR1, but not CYP3A4, were strongly associated with reductions in survival rates after LDLT with the Kaplan-Meier method and log-rank statistics (P =.020 and P =.135, respectively). With use of a Cox regression procedure, high levels of MDR1 (relative risk, 12.99; 95% confidence interval, 1.64-103.23), but not CYP3A4 (relative risk, 0.93; 95% confidence interval, 0.87-1.00) appeared to be a significant prognostic indicator for poor survival. CONCLUSIONS: Intestinal MDR1 is not only a good probe with which to predict the interindividual variation in tacrolimus pharmacokinetics after LDLT but also a powerful prognostic indicator for the outcome of LDLT.

Adolescent↗
PubMed2001

Human immunodeficiency virus type 1 Tat binding protein-1 is a transcriptional coactivator specific for TR.

The DNA-binding domain of nuclear hormone receptors functions as an interaction interface for other transcription factors. Using the DNA-binding domain of TRbeta1 as bait in the yeast two-hybrid system, we cloned the Tat binding protein-1 that was originally isolated as a protein binding to the human immunodeficiency virus type 1 Tat transactivator. Tat binding protein-1 has subsequently been identified as a member of the ATPase family and a component of the 26S proteasome. Tat binding protein-1 interacted with the DNA-binding domain but not with the ligand binding domain of TR in vivo and in vitro. TR bound to the amino-terminal portion of Tat binding protein-1 that contains a leucine zipper-like structure. In mammalian cells, Tat binding protein-1 potentiated the ligand-dependent transactivation by TRbeta1 and TRalpha1 via thyroid hormone response elements. Both the intact DNA-binding domain and activation function-2 of the TR were required for the transcriptional enhancement in the presence of Tat binding protein-1. Tat binding protein-1 did not augment the transactivation function of the RAR, RXR, PPARgamma, or ER. The intrinsic activation domain in Tat binding protein-1 resided within the carboxyl-terminal conserved ATPase domain, and a mutation of a putative ATP binding motif but not a helicase motif in the carboxyl-terminal conserved ATPase domain abolished the activation function. Tat binding protein-1 synergistically activated the TR-mediated transcription with the steroid receptor coactivator 1, p120, and cAMP response element-binding protein, although Tat binding protein-1 did not directly interact with these coactivators in vitro. In contrast, the N-terminal portion of Tat binding protein-1 directly interacted in vitro and in vivo with the TR-interacting protein 1 possessing an ATPase activity that interacts with the activation function-2 of liganded TR. Collectively, Tat binding protein-1 might function as a novel DNA-binding domain-binding transcriptional coactivator specific for the TR probably in cooperation with other activation function-2-interacting cofactors such as TR-interacting protein 1.

ATPases Associated with Diverse Cellular Activitie↗
PubMed2001

[Therapeutic drug monitoring of immunosuppresants].

The pharmacokinetics and pharmacodynamics of tacrolimus were evaluated in the pediatric recipients of living-related liver transplant. The mean clearance for tacrolimus was estimated with large interindividual variability and was shown to change as a function of days after operation. The therapeutic blood concentration of tacrolimus ranges were concerned from nearly 10 to 20 ng/ml. We have examined whether the expression levels of the intestinal absorptive barriers, MDR1 gene product P-glycoprotein and cytochrome P450 IIIA4(CYP3A4), correlate with the trough levels of orally administered tacrolimus in a recipient of small bowel transplant for 4 months. Both the MDR1 and CYP3A4 mRNA levels changed markedly through out this period. The tacrolimus concentration/dose ratio correlated well with the mRNA expression level of MDR1, but not CYP3A4. Intestinal P-glycoprotein rather than CYP3A4 is a good probe to predict the intraindividual variation in the tacrolimus pharmacokinetics.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2000

Detection of clonotypic IGH and TCR rearrangements in the neonatal blood spots of infants and children with B-cell precursor acute lymphoblastic leukemia.

An attractive hypothesis is that in utero exposure of hematopoietic cells to oncogenic agents can induce molecular changes leading to overt acute lymphoblastic leukemia (ALL) in infants and perhaps older children as well. Although supported by studies of identical infant twins with concordant leukemia, and of nontwined patients with MLL gene rearrangements, this concept has not been extended to the larger population of B-lineage ALL patients who lack unique nonconstitutive mutations or abnormally rearranged genes. We therefore sought to demonstrate a prenatal origin for 7 cases of B-cell precursor ALL (either CD10(+) or CD10(-)) that had been diagnosed in infants and children 14 days to 9 years of age. Using a polymerase chain reaction-based assay, we identified the same clonotypic immunoglobulin heavy-chain complementarity determining region or T-cell receptor V(D)2-D(D)3 sequences in the neonatal blood spots (Guthrie card) and leukemic cell DNAs of 2 infants with CD10(-) ALL and 2 of the 5 older patients with CD10(+) ALL. Nucleotide sequencing showed a paucity of N or P regions and shortened D germ line and conserved J sequences, indicative of cells arising from fetal hematopoiesis. Our findings strongly suggest a prenatal origin for some cases of B-cell precursor ALL lacking specific clonotypic abnormalities.

Base Sequence↗
PubMed2000

Expression of thyrotropin-releasing hormone (TRH) receptor subtype 1 in mouse pancreatic islets and HIT-T15, an insulin-secreting clonal beta cell line.

Thyrotropin-releasing hormone (TRH), originally isolated as a hypothalamic hormone, has been reported to be present and released from the pancreatic beta cells, affecting pancreatic functions. However, it still remains unclear whether TRH receptor is expressed in the pancreas. In the present study, we characterized TRH receptors (TRHR) in mouse pancreatic islets and HIT-T15 cells, a hamster clonal beta cell line. RT-PCR study showed significant expression of TRHR subtype 1 (TRHR1) mRNA in both mouse pancreatic islets and HIT-T15 (HIT) cells. In contrast, there was no expression of TRHR2 mRNA, a novel subtype of TRHR which is expressed predominantly in the central nervous system. Sequencing analysis demonstrated that TRHR1 of the islets was identical to that in the pituitary, and cloned hamster TRHR1 shared 93.3 % homology with that of the mouse at the nucleic acid level. Northern blot analysis of TRHR 1 mRNA in HIT-T15 cells showed a single strong hybridization signal approximately 3.7 kb in length. Furthermore, Scatchard plot analysis in HIT-T15 cells revealed that the Kd value for MeTRH was 0.63 nM. Significant elevation of intracellular calcium concentration was observed in response to as little as 10 nM TRH , and this was not affected by removal of extracellular calcium. This is the first description indicating the presence of functional TRH receptor subtype 1 in the pancreatic beta cells, and our observations suggested the regulation of pancreatic function by TRH through autocrine or paracrine mechanisms.

Amino Acid Sequence↗
PubMed2000

Effect of intestinal P-glycoprotein on daily tacrolimus trough level in a living-donor small bowel recipient.

We have examined whether the expression levels of the intestinal absorptive barriers, MDR1 gene product P-glycoprotein and cytochrome P450 IIIA4 (CYP3A4), correlate with the trough levels of orally administered tacrolimus in a recipient of small bowel transplant for 4 months. By using a competitive polymerase chain reaction, the expression of MDR1 messenger RNA (mRNA) and CYP3A4 mRNA by intestinal cells in a part of the mucosa biopsy specimen was evaluated. The average mRNA expression levels of MDR1 and CYP3A4 were 8.6 and 39.6 amol/microg total RNA, respectively. Both the MDR1 and CYP3A4 mRNA levels changed markedly throughout this period. The tacrolimus concentration/dose ratio correlated well with the mRNA expression level of MDR1, but not CYP3A4. These results suggested that intestinal P-glycoprotein rather than CYP3A4 is a good probe to predict the intraindividual variation in the tacrolimus pharmacokinetics during immunosuppressant therapy after small bowel transplantation.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2000

Outcome of clonal hemophagocytic lymphohistiocytosis: analysis of 32 cases.

We studied the impact of clonality, determined by analysis of Epstein-Barr virus genome termini, T-cell receptor genes and clonal chromosomal abnormality, on the clinical outcome in 32 patients with hemophagocytic lymphohistiocytosis (HLH). Of the cases studied, 23 cases were EBV-clonal, 15 cases were TCR-clonal and 7 cases were cytogenetically clonal. Thirty patients were treated with immuno-chemotherapy and/or multiagents' chemotherapy and 4 received bone marrow transplantation. All 7 cases, in which cytogenetically abnormal clones were identified, were fatal (3-year survival by Kaplan-Meier analysis; 14%, 95%CI: 0-40%). None of these 7 cases received bone marrow transplantation. On the other hand, the 3-year survival of 23 clonal EBV-positive HLH cases including 4 cytogenetically abnormal cases was 64 % (95%CI: 42-84%), while that of 15 TCR-clonal cases was 53% (95%CI: 26-78%). Our observations suggest that cytogenetically abnormal cases are at extremely high risk, requiring intensive immuno-chemotherapy followed by prompt and timely allogeneic bone marrow transplantation.

Adolescent↗
PubMed2000

Management of severe neutropenia with cyclosporin during initial treatment of Epstein-Barr virus-related hemophagocytic lymphohistiocytosis.

Severe neutropenia (absolute neutrophil count <500/gl) is probably due to the combined effects of dysregulated cytokine production and chemotherapeutic agents, and is one of the risk factors in the initial treatment of patients with Epstein-Barr virus-related hemophagocytic lymphohistiocytosis (EBV-HLH). We report here 9 cases of neutropenic HLH, of which 8 were treated with cyclosporin (CSA, 2-6 mg/kg/day; continuous infusion, or 6 mg/kg/day; per os, for periods ranging from 9 days to >8 weeks) in the initial neutropenic phase during induction treatment using corticosteroids and etoposide. Five of the 6 cases, in which CSA treatment was started early (before the second week of induction), survived the critical period with recovery of neutrophil counts within a week. The remaining 3 cases, in which CSA was introduced later or not at all, died of infection. Based on these results, we recommend a prompt short-term CSA infusion during neutropenic episodes in the most common treatment regimen of etoposide and corticosteroids in patients with HLH. Improved neutrophil recovery as a result of CSA treatment makes it possible to continue immunochemotherapy safely and obtain improved patient outcomes.

Adolescent↗
PubMed1999

Abundance of cyclo (His-Pro)-like immunoreactivity in the brain of TRH-deficient mice.

Cyclo(His-Pro) or CHP was initially discovered as a metabolite of thyrotropin-releasing hormone (TRH) resulting from the action of the enzyme Pyroglutamyl aminopeptidase. Physiologic and pharmacologic studies that followed this initial discovery provided indirect evidence that all CHP may not be derived from TRH. However, the recent availability of a TRH-deficient mouse has made it possible to reinvestigate whether CHP is derived from TRH. In the present study, we examined distribution of CHP and TRH in TRH-deficient mice. Northern blot analysis confirmed the absence of preproTRH mRNA in both the hypothalamus and the cortex of TRH-deficient mice. Brains from the wild-type and TRH-deficient mice were dissected into 7 regions, and TRH and CHP concentrations were determined by specific radioimmunoassay (RIA) in each region. Whereas TRH was identified in all regions of the wild-type brain, with the highest concentration in the hypothalamus, no detectable TRH was observed in any region in the TRH-deficient mice. While CHP-like immunoreactivity (CHP-LI) was present in all regions in the wild-type brain, its concentration was reduced by approximately 50% in the hypothalamus and cerebral cortex of TRH-deficient mice, with no change in other brain regions. Furthermore, the CHP-LI present in the brain of TRH-deficient mice was immunologically and chromatographically identical to synthetic CHP. These findings strongly suggest that a portion of the CHP in the brain is derived from sources other than TRH.

Animals↗
PubMed1999

Regulation of the mouse preprothyrotropin-releasing hormone gene by retinoic acid receptor.

Retinoic acid (RA) has been reported to inhibit the secretion and synthesis of the pituitary TSH in vivo and in vitro. However, little is known about the influence of RA on the expression of the prepro-TRH gene. We therefore investigated whether the promoter activity of the mouse TRH gene is directly regulated by RA using a transient transfection assay into CV-1 cells. In the absence of cotransfected RA receptor (RAR), all-trans-RA did not affect the promoter activity. In contrast, the cotransfected RARalpha significantly stimulated promoter activity in the absence of ligand, and all-trans-RA reversed basal promoter activation. The cotransfected thyroid hormone receptor-beta (TRbeta), but not 9-cis-RA receptor (RXR), had an additive effect on the RAR-dependent stimulation. TR and RAR can similarly interact with the corepressor proteins, and the cotransfected nuclear receptor corepressor (N-CoR) has been demonstrated to augment the transcriptional stimulation of the TRH gene by unliganded TR. As observed with TR, the coexpression of a N-CoR variant significantly enhanced the ligand-independent stimulation by RAR. A mutant RAR (RAR403) lacking the C-terminal activation function-2 (AF-2) activation domain that was essential for ligand-induced corepressor release constitutively stimulated the promoter activity. The constitutive stimulation by RAR403 was augmented by the cotransfected N-CoR variant. A deletion analysis of the 5'-flanking region of the TRH gene revealed that the minimal promoter region for the regulation by RAR was -83 to +53, with a consensus half-site motif for the thyroid hormone response element at -57. In contrast to the strong binding of TR to the thyroid hormone response element half-site in gel retardation assays, no binding of RAR homodimer, RAR/ RXR heterodimer, or RAR/TR heterodimer was observed to the minimal promoter region. These results collectively suggest that RAR without heterodimerization with RXR and TR regulates transcription of the mouse TRH gene in cooperation with the corepressor, and that the DNA binding of RAR appeared to be unnecessary for regulation of the TRH gene promoter.

Animals↗
PubMed1998

Genomic organization and promoter function of the mouse uncoupling protein 2 (UCP2) gene.

We cloned and characterized the mouse uncoupling protein 2 (UCP2) gene and its promoter region. The gene spans approximately 6.3 kb and contains eight exons and seven introns. Two short exons are located in the 5' untranslated region, and each of the remaining exons encodes one of the transmembrane domains. 3'-RACE analysis showed that a polyadenylation signal 257 bp downstream from the stop codon was functional. Primer extension analysis indicated a single transcriptional start site 369 bp upstream from the translational start site. The promoter region lacks both TATA and CAAT boxes but is GC-rich. A construct containing 1250 bp of the promoter region showed significant activity in all 6 cell lines examined, and the region between -160 and -678 bp exhibited strong positive regulatory activity. These features of the UCP2 gene are different from those of the UCP1 gene and may contribute to its ubiquitous expression.

Amino Acid Sequence↗
PubMed1998

Effect of ultrahigh-dose methylcobalamin on compound muscle action potentials in amyotrophic lateral sclerosis: a double-blind controlled study.

To develop a symptomatic treatment for amyotrophic lateral sclerosis, we compared the effects of ultrahigh-dose and low-dose (25 and 0.5 mg/day, intramuscularly, for 14 days) methylcobalamin on averaged compound muscle action potential amplitudes (CMAPs) in a double-blind trial. No significant changes in CMAP amplitude were found in 12 patients who had the low-dose treatment at either 2 or 4 weeks after start of treatment. By contrast, 12 patients assigned to the ultrahigh-dose group demonstrated a significant increase at 4 weeks. This method may provide a clinically useful measure to improve or retard muscle wasting, if a larger extended trial fulfills its promise.

Action Potentials↗
PubMed1998

Effect of clarithromycin on renal excretion of digoxin: interaction with P-glycoprotein.

We present a digoxin-clarithromycin interaction in two patients in whom digoxin concentrations were unexpectedly increased. The ratio of renal digoxin clearance to creatinine clearance in one patient was lower during the concomitant administration of clarithromycin (0.64 and 0.73) than that after cessation of clarithromycin administration (1.30 +/- 0.20; mean +/- SD). Because P-glycoprotein could play an important role in the renal secretion of digoxin, we hypothesized that clarithromycin decreases renal digoxin excretion by inhibiting P-glycoprotein-mediated transport. Digoxin transport was evaluated with use of a kidney epithelial cell line, which expresses the human P-glycoprotein on the apical membrane by transfection with MDR1 complementary deoxyribonucleic acid. Clarithromycin inhibited the transcellular transport of digoxin from the basolateral to the apical side in a concentration-dependent manner and concomitantly increased the cellular accumulation of digoxin. These results suggest that clarithromycin may inhibit the P-glycoprotein-mediated tubular secretion of digoxin, and this interaction mechanism may contribute to an increase in the serum digoxin concentration.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1996

The evolution of immunosuppression with FK506 in pediatric living-related liver transplantation.

The effects of three FK506 induction regimens on pediatric living-related liver transplantation (LRLT) were studied retrospectively in terms of patient survival and adverse side effects. The patients consisted of 120 children, ranging from 3 to 210 months of age, who underwent a total of 122 LRLTs with a minimum follow-up of 6 months. Immunosuppression consisted of FK506 and low-dose steroids. FK506 was given in 3 ways: (1) high-dose intravenous (i.v.) induction, with FK506 begun at a dose of 0.15 mg/kg/day for the first 16 patients; (2) low-dose i.v. induction, with FK506 begun at a dose of 0.06 mg/kg/day for the next 45 patients; and (3) per os (p.o.) induction, with FK506 begun orally from the day prior to LRLT and continued postoperatively. Whole-blood trough levels of FK506 were monitored daily. Trough levels in the high induction group were often as high as 100 ng/ml compared with the level of 20 ng/ml in the p.o. induction group. Patient survivals were 75%, 89%, and 80% in the high-i.v. vs. low-i.v. vs. p.o. groups. The incidences of acute rejection were 12.5%, 22.2%, and 26.4%, and the incidences of viral infection were 56%, 38%, and 11% in the respective groups. Major adverse effects occurred with higher frequency in the high-i.v. induction group. Oral FK506 induction therapy at a dose of 0.15 mg/kg/day starting from the day before LRLT was safer and associated with a lower incidence of viral infection than therapy with i.v. FK506.

Administration, Oral↗