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Biomedical subjects

T Hayashi

Publications and source records attributed to T Hayashi.

At least 37 records · Page 2Linked to original sources
PubMed2006

Protective role of protein C inhibitor in monocrotaline-induced pulmonary hypertension.

BACKGROUND: Protein C inhibitor (PCI) plays a role in multiple biological processes including fertilization, coagulation, fibrinolysis and kinin systems. OBJECTIVES: We hypothesized that PCI participates in the pathogenesis of pulmonary hypertension. To demonstrate this, we compared the development of pulmonary hypertension in mice overexpressing PCI in the lung with wild-type (WT) mice. Pulmonary hypertension was induced by s.c. injection of 600 mg kg-1 of monocrotaline weekly for 8 weeks. RESULTS: Right ventricular arterial pressure was significantly increased in monocrotaline-treated WT mice compared with that in monocrotaline-treated transgenic mice. Bronchoalveolar lavage fluid (BALF) levels of thrombin-antithrombin complex, monocyte chemoattractant protein-1 and platelet-derived growth factor, and the plasma level of tumor necrosis factor-alpha were significantly increased in monocrotaline-treated WT mice as compared with monocrotaline-treated PCI transgenic mice. Increased level of PCI-thrombin complex was detected in BALF from monocrotaline-treated PCI transgenic mice as compared with saline-treated PCI transgenic mice. CONCLUSIONS: This study showed that increased expression of PCI in the lung is protective against monocrotaline-induced pulmonary hypertension, suggesting a potential beneficial effect of PCI for the therapy of this disease.

Animals↗
PubMed2006

Disorder of the saliva melatonin circadian rhythm in patients with Meniere's disease.

OBJECTIVES: Stress is involved in the development of symptoms of Meniere's disease (MD). Stress-related disease has been reported to be associated with disorders in the circadian rhythm of melatonin (MEL) which regulates that rhythm. We therefore investigated MEL circadian rhythm of patients with MD. PATIENTS AND METHODS: A comparison of 13 MD patients was made with age-matched controls. Saliva samples were collected every 3 h. A statistical analysis of the circadian rhythm of saliva MEL was performed for a circadian rhythm by the fit of a 24- and 12-h composite cosine model. In addition, we assessed the stress and depression status of the two groups. RESULTS: The rhythmic amplitude of MEL in the MD group was significantly lower than that in the control group (P < 0.05). The acrophase in the MD group was significantly earlier than that in the control group (P < 0.05). MD patients had significantly higher stress score and depression score than control subjects (P < 0.05). The amplitude in MD patients had no significant correlation with their otologic clinical data. CONCLUSIONS: These results suggest that MD patients have a MEL deficiency, which is related to their stress and depression status rather than the otologic pathological status of MD.

Adult↗
PubMed2006

Assignment of 204 genes localized on HSA17 to a porcine RH (IMpRH) map to generate a dense comparative map between pig and human/mouse.

Bi- and uni-directional chromosome painting (ZOO-FISH) and gene mapping have revealed correspondences between human chromosome (HSA) 17 and porcine chromosome (SSC) 12 harboring economically important quantitative trait loci. In the present study, we have assigned 204 genes localized on HSA17 to SSC12 to generate a comprehensive comparative map between HSA17 and SSC12. Two hundred fifty-five primer pairs were designed using porcine sequences orthologous with human genes. Of the 255 primer pairs, 208 (81.6%) were used to assign the corresponding genes to porcine chromosomes using the INRA-Minnesota 7000-rad porcine x Chinese hamster whole genome radiation hybrid (IMpRH) panel. Two hundred three genes were integrated into the SSC12 IMpRH linkage maps; and one gene, PPARBP, was found to link to THRA1 located in SSC12 but not incorporated into the linkage maps. Three genes (GIT1, SLC25A11, and HT008) were suggested to link to SSC12 markers, and the remaining gene (RPL26) did not link to any genes/expressed sequence tags/markers registered, including those in the present study. A comparison of the gene orders among SSC12, HSA17, and mouse chromosome 11 indicates that intra-chromosomal rearrangements occurred frequently in this ancestral mammalian chromosome during speciation.

Acetyltransferases↗
PubMed2006

Assignment of 101 genes localized in HSA10 to a swine RH (IMpRH) map to generate a dense human-swine comparative map.

Economically important traits such as growth and backfat in pigs have been shown to be influenced by genes in swine chromosome (SSC) 10q12-->qter corresponding to human chromosome (HSA) 10p. However, since gene information in the swine chromosomal region was limited, we attempted to generate a dense comparative map between SSC10 and HSA10 by mapping the 115 genes of HSA10 to a swine RH map (IMpRH map). In the mapping ten genes were assigned to SSC10, 88 to SSC14, and one to SSC3. One gene was suggested to link to SSC3, and another to SSC9. The correspondences between HSA10 and SSC10 and between HSA10 and SSC14 were essentially consistent with the observations obtained from bi/uni-directional chromosome painting or other results. This study further indicated that a large number of intrachromosomal rearrangements occurred in the synteny-conserved regions following species separation.

Animals↗
PubMed2006

Regulated production of activin A and inhibin B throughout the cycle of the seminiferous epithelium in the rat.

Production and regulation of activin A and inhibin B during the cycle of the seminiferous epithelium were investigated in adult rats. Immunohistochemistry localised the activin beta(A)-subunit to the Sertoli cell cytoplasm, with much weaker expression in spermatocytes and spermatids. Both activin A and inhibin B, measured by ELISA were secreted by, seminiferous tubule fragments over 72 h in culture. Activin A was secreted in a cyclic manner with peak secretion from tubules isolated at stage VIII. Tubules collected during stage VI produced the least activin A. Inhibin B secretion was highest from stage IX-I tubules and lowest from stage VII tubules. Addition of interleukin-1beta (IL-1beta) had relatively little effect on activin A or inhibin B secretion in culture. In contrast, the peak secretion of activin A by stage VIII tubules was blocked by co-incubation with an excess of human recombinant IL-1 receptor antagonist, whereas inhibin B secretion increased slightly. Dibutyryl cAMP stimulated activin A secretion by late stage VII and VIII tubules and stimulated inhibin B across all stages. These data indicate that activin A and inhibin B are cyclically regulated within the seminiferous epithelium, with endogenous IL-1 (presumably IL-1alpha produced by the Sertoli cells), responsible for a peak of activin A production subsequent to sperm release at stage VIII. These data provide direct evidence that production of activin A and inhibin B by the Sertoli cell is locally modulated by IL-1alpha , in addition to FSH/cAMP, under the influence of the developing spermatogenic cells.

Activins↗
PubMed2006

Identification of quantitative trait loci affecting corpora lutea and number of teats in a Meishan x Duroc F2 resource population.

Understanding of the genetic control of female reproductive performance in pigs would offer the opportunity to utilize natural variation and improve selective breeding programs through marker-assisted selection. The Chinese Meishan is one of the most prolific pig breeds known, farrowing 3 to 5 more viable piglets per litter than Western breeds. This difference in prolificacy is attributed to the Meishan's superior prenatal survival. Our study utilized a 3-generation resource population, in which the founder grandparental animals were purebred Meishan and Duroc pigs, in a genome scan for QTL. Grandparent, F1, and F2 animals were genotyped for 180 microsatellite markers. Reproductive traits, including number of corpora lutea (number of animals = 234), number of fetuses per animal (n = 226), number of teats (n = 801), and total number born (n = 288), were recorded for F2 females. Genome-wide significance level thresholds of 1, 5, and 10% were calculated using a permutation approach. We identified 9 QTL for 3 traits at a 10% genome-wise significance level. Parametric interval mapping analysis indicated evidence of a 1% genome-wise significant QTL for corpora lutea on SSC 3. Nonparametric interval mapping for number of teats found 4 significant QTL on chromosomes SSC3 (P < 0.01), SSC7 (P < 0.01), SSC8 (P < 0.01), and SSC12 (P < 0.05). Partial imprinting of a QTL affecting teat number (P < 0.10) was detected on SSC8. Using the likelihood-ratio test for a categorical trait, 2 QTL for pin nipples were detected on SSC2 and SSC16 (P < 0.01). Fine mapping of the QTL regions will be required for their application to introgression programs and gene cloning.

Alleles↗
PubMed2005

Cisplatin-incorporating polymeric micelles (NC-6004) can reduce nephrotoxicity and neurotoxicity of cisplatin in rats.

In spite of the clinical usefulness of cisplatin (CDDP), there are many occasions in which it is difficult to continue the administration of CDDP due to its nephrotoxicity and neurotoxicity. We examined the incorporation of CDDP into polymeric micelles to see if this allowed the resolution of these disadvantages. Cisplatin was incorporated into polymeric micelles through the polymer-metal complex formation between polyethylene glycol poly(glutamic acid) block copolymers and CDDP (NC-6004). The pharmacokinetics, pharmacodynamics, and toxicity studies of CDDP and NC-6004 were conducted in rats or mice. The particle size of NC-6004 was approximately 30 nm, with a narrow size distribution. In rats, the area under the curve and total body clearance values for NC-6004 were 65-fold and one-nineteenth the values for CDDP (P<0.001 and 0.01, respectively). In MKN-45-implanted mice, NC-6004 tended to show antitumour activity, which was comparable to or greater than that of CDDP. Histopathological and biochemical studies revealed that NC-6004 significantly inhibited the nephrotoxicity of CDDP. On the other hand, blood biochemistry revealed transient hepatotoxicity on day 7 after the administration of NC-6004. Furthermore, rats given CDDP showed a significant delay (P<0.05) in sensory nerve conduction velocity in their hind paws as compared with rats given NC-6004. Electron microscopy in rats given CDDP indicated the degeneration of the sciatic nerve, but these findings were not seen in rats given NC-6004. These results were presumably attributable to the significantly reduced accumulation of platinum in nerve tissue when NC-6004 was administered (P<0.05). NC-6004 preserved the antitumour activity of CDDP and reduced its nephrotoxicity and neurotoxicity, which would therefore seem to suggest that NC-6004 could allow the long-term administration of CDDP where caution against hepatic dysfunction must be exercised.

Animals↗
PubMed2005

Comparative characterization study of microporous carbons by HRTEM image analysis and gas adsorption.

The present work presents a useful comparison of micropore size distributions (MPSDs) obtained from gas adsorption and image analysis of high-resolution transmission electron micrographs. It is shown that the MPSD obtained for a chemical activated carbon is concordant with that obtained from CO2 adsorption. In addition, this technique has allowed us to obtain the MPSD of a carbon molecular sieve (CMS) prepared in our laboratory by a copyrolysis process, which could only be characterized by CO2 adsorption at 273 K (not by N2 adsorption at 77 K due to diffusional problems). The MPSD obtained by high-resolution transmission electron microscopy (HRTEM) for the CMS is wider than that obtained by CO2 adsorption, suggesting that HRTEM is detecting the closed porosity existing in this sample, which is not accessible to gas adsorption. The existence of closed porosity in the CMS is explained considering the preparation method used. Thus, HRTEM combined with image analysis seems to be useful for structural analysis of narrow micropores including closed porosity.

Journal Article↗
PubMed2005

Electrical pump-and-probe study of spin singlet-triplet relaxation in a quantum dot.

Spin relaxation from a triplet excited state to a singlet ground state in a semiconductor quantum dot is studied by employing an electrical pump-and-probe method. Spin relaxation occurs via co-tunneling when the tunneling rate is relatively large, confirmed by a characteristic square dependence of the relaxation rate on the tunneling rate. When co-tunneling is suppressed by reducing the tunneling rate, the intrinsic spin relaxation is dominated by spin-orbit interaction. We discuss a selection rule of the spin-orbit interaction based on the observed double-exponential decay of the triplet state.

Journal Article↗
PubMed2005

Elevation of both cyclooxygenase-2 and prostaglandin E2 receptor EP3 expressions in rat placenta after uterine artery ischemia-reperfusion.

Intrauterine growth restriction (IUGR) has a multifactorial pathogenesis and is an important cause of perinatal mortality. The relationship between fetal weight and placental blood flow in an animal model of IUGR has been investigated, showing that fetal growth is regulated by placental blood flow. The aim of the present study was to determine whether ischemia-reperfusion (I/R) injury stimulates the prostaglandin E2 (PGE2) system or the vascular endothelial growth factor (VEGF) system in the placenta of a rat IUGR model. COX-2 is reported to be involved in ischemic damage in many organs. There are 4 types of PGE2 receptor (EP1, EP2, EP3 and EP4). It is well known that EP1 and EP3 is associated with vasoconstriction. In the present study, vessels were occluded in the right uterine horn on day 17 of pregnancy in rats, and the clamps were removed after 30 min of ischemia. At 24h, 48 h, and 5 days after I/R injury, the live fetuses and placentas were obtained by cesarean section. This study revealed that I/R injury caused IUGR 5 days after the treatment. COX-2 expression and EP3 receptor expression were significantly elevated at 24h after I/R injury, but VEGF mRNA expression was not altered in the placenta from the ischemic horn compared with the non-ischemic horn. These results suggested that induction of the COX-2-EP3 system in the placenta may be one of the causes of IUGR induced by uterine ischemia, because the EP3 receptor and PGE2 are well known to mediate vasoconstriction in many organs.

Animals↗
PubMed2005

Fluorination of double-walled carbon nanotubes.

Fluorine atoms are selectively attached to the sidewall of the outer shell of DWNTs without disrupting the double-layered morphology; the stoichiometry of the fluorinated DWNTs is CF(0.30).

Journal Article↗
PubMed2005

Nanotechnology: 'buckypaper' from coaxial nanotubes.

Double-walled carbon nanotubes are needed in a pure, highly crystalline form before features such as their electronic properties, thermal transport and mechanical behaviour can be investigated. Here we fabricate a paper-like material that consists of hexagonally packed bundles of clean, coaxial carbon nanotubes whose double walls vary little in diameter; it is prepared in high yields using chemical-vapour deposition with a conditioning catalyst and two-step purification. Our results will enable investigation of the physical properties of double-walled carbon nanotubes, which are predicted to be superior to those of both their single- and multiwalled relatives.

Journal Article↗
PubMed2005

Type IX collagen is crucial for normal hearing.

cDNA microarray analysis indicated that COL9A1 and COL9A3 are highly expressed in the human inner ear, suggesting that type IX collagen has a crucial functional role in the inner ear. This study further confirmed, by means of real-time PCR, the presence of collagen type IX genes in the mouse inner ear. Immunocytochemical analysis also revealed that type IX collagen is distributed in the tectorial membrane, where it co-localizes with type II collagen, indicating that type IX collagen may contribute to the three-dimensional integrated structure of type II collagen molecules. Mice with targeted disruption of the col9a1 gene were shown through assessment by auditory brain stem response to have hearing loss, suggesting an important role of type IX collagen in maintaining normal hearing. At the light microscopic level, the tectorial membrane of knock-out mice was found to be abnormal in shape, and electron microscopy confirmed disturbance of organization of the collagen fibrils. An antibody against type II collagen failed to detect type II collagen in the tectorial membrane of type IX collagen knock-out mice, suggesting that a lack of type IX collagen may affect the three-dimensional structure of type II collagen molecules. These findings indicate that genes encoding each chain of type IX collagen may fulfill an important function associated with the tectorial membrane in the auditory system.

Animals↗
PubMed2005

Modification of ovary stock solution with magnesium and raffinose improves the developmental competence of oocytes after long preservation.

During ovary storage oocytes lose some of their developmental competence. In the present study, we maintained storage solutions of phosphate-buffered saline (PBS) at various temperatures (20 or 35 degrees C) or supplemented them with magnesium (Mg), raffinose and sucrose. Subsequently, we examined the kinetics of electrolytes in the follicular fluid (FF) during the ovary storage period (9 h), the survival rate of granulosa cells in the follicles, and the developmental competence of oocytes after the storage. Lowering the temperature from 35 to 20 degrees C increased the total cell number of blastocysts that developed at 7 days after in vitro maturation and in vitro fertilization of oocytes. In stock solution with supplements of 15 mM Mg or a combination of 5 mM Mg and 10 mM raffinose or sucrose, a significantly higher number of oocytes developed into blastocysts with a large number of cells in each blastocyst, and a significantly higher number of living granulosa cells were obtained as compared with stock solutions without any supplements. During ovary storage, the concentrations of potassium and chloride in the FF were increased, and the addition of Mg to the stock solution increased the concentration of Mg in the FF. Germinal vesicle breakdown in oocytes that were collected from ovaries stored in the solution supplemented with 15 mM Mg or a combination of 5 mM Mg and 10 mM of raffinose occurred at a slower rate than that in oocytes collected from ovaries stored in PBS alone. On the other hand, the oocytes collected from ovaries stored in the solution supplemented with 15 mM Mg or a combination of 5 mM Mg and 10 mM raffinose reached the metaphase II (MII) stage more rapidly than the oocytes collected from ovaries stored in the PBS alone. In conclusion, the modification of stock solution by the addition of Mg and raffinose improved the developmental competence of oocytes obtained from ovaries preserved for a long period.

Animals↗
PubMed2005

Reduced-intensity stem-cell transplantation for adult acute lymphoblastic leukemia: a retrospective study of 33 patients.

Efficacy of reduced-intensity stem-cell transplantation (RIST) for acute lymphoblastic leukemia (ALL) was investigated in 33 patients (median age, 55 years). RIST sources comprised 20 HLA-identical related donors, five HLA-mismatched related, and eight unrelated donors. Six patients had undergone previous transplantation. Disease status at RIST was first remission (n=13), second remission (n=6), and induction failure or relapse (n=14). All patients tolerated preparatory regimens and achieved neutrophil engraftment (median, day 12.5). Acute and chronic graft-versus-host disease (GVHD) developed in 45 and 64%, respectively. Six patients received donor lymphocyte infusion (DLI), for prophylaxis (n=1) or treatment of recurrent ALL (n=5). Nine patients died of transplant-related mortality, with six deaths due to GVHD. The median follow-up of surviving patients was 11.6 months (range, 3.5-37.3 months). The 1-year relapse-free and overall survival rates were 29.8 and 39.6%, respectively. Of the 14 patients transplanted in relapse, five remained relapse free for longer than 6 months. Cumulative rates of progression and progression-free mortality at 3 years were 50.9 and 30.4%, respectively. These findings suggest the presence of a graft-versus-leukemia effect for ALL. RIST for ALL is worth considering for further evaluation.

Adolescent↗
PubMed2005

Bayesian mapping of QTL in outbred F2 families allowing inference about whether F0 grandparents are homozygous or heterozygous at QTL.

In this paper, we propose a new Bayesian method for QTL analysis in outbred F2 families based on Markov chain Monte Carlo (MCMC) estimation allowing inference about whether each of F0 founders (grandparents) is homozygous or heterozygous at QTL. This, in turn, allows us to select a model accurately explaining observations of phenotypes for F2 individuals. The proposed method performs the fitting a statistical model of the two possible QTL states in each F0 grandparent, that is, homozygous and heterozygous at QTL, and gives a posterior distribution for the QTL states in each F0 grandparent. We confine ourselves to the discrimination of two QTL states, homozygous or heterozygous, for each of the F0 grandparents without taking into consideration whether common alleles are shared by F0 grandparents. The statistical model includes allelic effects and dominance effects for each QTL. The number of parameters representing allelic effects and dominance effects is therefore changed depending on the QTL states. A Reversible Jump MCMC technique is used for transition between the models of different dimensions. The effectiveness of the proposed method was investigated using simulation experiments. It was practicable to estimate the QTL states of F0 grandparents as well as the number, the locations and the effects of QTL segregating in an outbred F2 family.

Alleles↗