Biomedical subjects
H Ohashi
Publications and source records attributed to H Ohashi.
[Fetal radiation syndrome].
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[Fetal thalidomide syndrome].
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Angiographic assessment of surgical reconstructions for left ventricular asynergy with indices of abnormally contracting segments.
BACKGROUND: In surgical reconstruction for left ventricular asynergy after myocardial infarction, the conventional linear closure technique second to simple resection and endoventricular circular patch plasty, which is the so-called Dor technique, are commonly utilized. We assessed these techniques using an abnormally contracting segment (ACS) in the left ventriculogram. METHODS: We reviewed 10 and 15 patients who underwent the linear technique (group L) and the Dor technique (group D), respectively. %ACS was determined as the percent ratio of both akinetic and dyskinetic chords among the total chords in the centerline method of regional wall motion analysis. A difference between preoperative and postoperative ejection fraction (EF) was generated by preoperative EF and this percentage ratio was determined as %EF. RESULTS: Postoperative EF improved from 31% to 41% in group L and from 33% to 49% in group D (p<0.05). Postoperative EF in group D was higher than in group L (p<0.05). %ACS decreased from 41% to 34% in group L and from 41% to 19% in group D (p<0.05). Postoperative %ACS was lower in group D than in group L (p<0.05). The significant correlation between preoperative %ACS and %EF was negative in group L and positive in group D (p<0.05). CONCLUSIONS: The Dor technique is more effective for the postoperative systolic function than the linear technique because more extensive reduction in %ACS is possible with the Dor technique than with the linear technique. Dor technique becomes more crucial to the postoperative systolic function as the preoperative %ACS becomes larger.
Standard growth curves for Japanese patients with Prader-Willi syndrome.
We constructed the standard growth (length/height and weight) curves for Japanese individuals with Prader-Willi syndrome (PWS). Crude height and weight data were collected from 153 males and 99 females with the syndrome, and the collected data were arranged by a mathematical method to construct the curves. Height growth patterns were quite different between PWS and normal children. Mean height of individuals with the syndrome by puberty is -2 SD for normal children, and it drops off far below -2 SD value after puberty. Final mean height is 141.2 +/- 4.8 cm for females (n = 13) and 147.7 +/- 7.7 cm for males (n = 17), showing 15.8 and 21.9 cm below the average height for normal Japanese girls and boys, respectively. Thus, the degree of shortness is more pronounced in male than in female patients. There was no difference in height between those with chromosome 15q deletion and those without. Mean weight at birth of girls (n = 88) and boys (n = 131) were 2.70 +/- 0.45 Kg and 2.62 +/- 0.47 Kg, respectively. These values were smaller than those for normal neonates (P < 0.05, t-test). The weight of PWS children was under the mean value for normal infants by age 2 years, but gradually increase above the mean values for normal children around ages 2-4 years. Overweight in both males and females becomes obvious during prepuberty. Growth patterns are not different between Japanese and Caucasian children with the syndrome. Short stature is more prominent in boys of both ethnic groups, whereas the degree of overweight appears much more severe in Caucasians.
Direct radiolabeling by [3H]quisqualic acid of group I metabotropic glutamate receptor in rat brain synaptic membranes.
[3H]Quisqualic acid (QA) was synthesized and used to label metabotropic glutamate receptor (mGluR) in rat brain synaptic membranes in the presence of three different ionotropic glutamate receptor agonists at respective saturating concentrations. Of several mGluR agonists tested, group I agonists were more potent in displacing [3H]QA binding than group II and group III agonists in the presence of the three ionotropic agonists. [3H]QA binding was markedly inhibited by guanine nucleotide analogues in a concentration-dependent manner at a concentration range of 10 nM to 1 mM. Scatchard analysis revealed that [3H]QA binding consisted of a single component with a K(d) of 50.9+/-5.3 nM and a B(max) of 431. 6+/-18.3 fmol/mg protein. These results suggest that [3H]QA indeed labels group I mGluR functionally coupled to GTP binding protein in rat brain synaptic membranes when determined under the experimental conditions employed.
Novel and recurrent EBP mutations in X-linked dominant chondrodysplasia punctata.
Chondrodysplasia punctata (CDP) is a heterogeneous group of skeletal dysplasias characterized by stippled epiphyses. A subtype of CDP, X-linked dominant chondrodysplasia punctata (CDPX2), known also as Conradi-Hünermann-Happle syndrome, is a rare skeletal dysplasia characterized by short stature, craniofacial defects, cataracts, ichthyosis, coarse hair, and alopecia. The cause of CDPX2 was unknown until recent identification of mutations in the gene encoding Delta(8),Delta(7) sterol isomerase emopamil-binding protein (EBP). Twelve different EBP mutations have been reported in 14 patients with CDPX2 or unclassified CDP, but with no evidence of correlation between phenotype and nature of the mutation. To characterize additional mutations and investigate possible phenotype-genotype correlation, we sequenced the entire EBP gene in 8 Japanese individuals with CDP; 5 of them presented with a CDPX2 phenotypes. We found EBP mutations in all 5 CDPX2 individuals, but none in non-CDPX2 individuals. Three of these CDPX2 individuals carried novel nonsense mutations in EBPand the other two, separate missense mutations that had been reported also in different ethnic groups. Our results, combined with previous information, suggest all EBP mutations that produce truncated proteins result in typical CDPX2, whereas the phenotypes resulted from missense mutations are not always typical for CDPX2. Patients with nonsense mutations showed abnormal sterol profiles consistent with a defect in Delta(8), Delta(7) sterol isomerase. X-inactivation patterns of the patients showed no skewing, an observation that supports the assumption that inactivation of the EBP gene occurs at random in affected individuals.
Neurotensin-induced Cl(-) current in guinea-pig dorsal root ganglion cells.
In guinea-pig dorsal root ganglion cells held under voltage-clamp at -80 mV, neurotensin elicited an inward current (I(NT)) whose amplitude increased with increasing neurotensin concentration (40-4000 nM). The effect was blocked by a nonpeptide neurotensin antagonist. I(NT) occurred in the absence of the extracellular Na(+), but not in the absence of the intracellular Cl(-), and it was outward directed by reversing the driving force for Cl(-). I(NT), like the gamma-amino-butyric acid (GABA)-induced Cl(-) current (I(GABA)), remained little changed after virtual elimination of cytosolic free-ionized Ca(2+) or after treatment with a Ca(2+)-activated Cl(-) channel blocker, but, in contrast to I(GABA) it was resistant to the I(GABA) blocker picrotoxin, slower in time course and more easily desensitized when repeatedly elicited. I(NT) and I(GABA) were additive to each other. AG-protein inhibitor markedly reduced I(NT), and a G-protein activator produced an inward current during which no current could be elicited by neurotensin. These results show that neurotensin exerts an effect to activate Ca(2+)-insensitive Cl(-) channels distinct from those activated by GABA in guinea-pig dorsal root ganglion cells, and the effect may arise through a G-protein-dependent mechanism.
Rabies virus infection prevents the modulation by alpha(2)-adrenoceptors, but not muscarinic receptors, of Ca(2+) channels in NG108-15 cells.
In mouse neuroblastoma x rat glioma hybrid (NG108-15) cells, we examined whether rabies virus infection affects the voltage-dependent Ca(2+) current (I(Ca)) and agonist-induced I(Ca) inhibition. The viral infection had little effect on the current-voltage relationship for peak I(Ca) or on the late I(Ca) that remained at the end of a 200-ms step depolarization. Noradrenaline and carbachol, via alpha(2)-adrenoceptors and muscarinic receptors, respectively, reduced I(Ca) concentration dependently. The maximum effect of noradrenaline was attained at 10 microM with 19.4+/-1.8% inhibition of I(Ca), which was significantly decreased to 9.9+/-1.3% after viral infection. The decrease was not reversed with 100 microM noradrenaline, suggesting that it does not result from a decrease in agonist sensitivity of cells. The maximum effect of carbachol (300 microM; 27.7+/-2.9% inhibition) remained unchanged, despite carbachol sharing intracellular signaling pathways with noradrenaline. These results indicate that in NG108-15 cells, rabies virus infection does not alter the functional expression of voltage-dependent Ca(2+) channels, but it attenuates the alpha(2)-adrenoceptor-mediated I(Ca) inhibition, possibly through some change at the receptor level.
Haplotype-phenotype correlation in Fukuyama congenital muscular dystrophy.
In typical Fukuyama congenital muscular dystrophy (FCMD), peak motor function is usually only unassisted sitting or sliding on the buttocks, though a few patients are able to walk at some point. However, a few patients have a severe phenotype and never acquire head control. In addition, it is clinically difficult to differentiate this severe FCMD from Walker-Warburg syndrome (WWS) or from muscle-eye-brain disease (MEBD). In order to establish a genotype-phenotype correlation, we performed haplotype analysis using microsatellite markers closest to the FCMD gene (FCMD) in 56 Japanese FCMD families, including 35 families whose children were diagnosed as FCMD with the typical phenotype, 12 families with a mild phenotype, and 9 families with a severe phenotype. Of the 12 propositi with the mild phenotype, 8 could walk and the other 4 could stand with support; 10 cases were homozygous for the ancestral founder (A-F) haplotype whereas the other 2 were heterozygous for the haplotype. In the 9 severe cases, who had never acquired head control or the ability to sit without support, 3 had progressive hydrocephalus, 2 required a shunt operation, and 7 had ophthalmological abnormalities. Haplotype analysis showed that 8 of the 9 cases of the severe phenotype are heterozygous for the A-F haplotype, and the other one homozygous for the haplotype. We confirmed that at least one chromosome in each of the 56 FCMD patients has the A-F haplotype. The rate of heterozygosity for the A-F haplotypes was significantly higher in severe cases than in typical or mild cases (P < 0.005). Severe FCMD patients appeared to be compound heterozygotes for the founder mutation and another mutation. Thus, the present study yielded molecular genetic evidence of a broad clinical spectrum in FCMD.
Molecular cytogenetic analysis of eight inversion duplications of human chromosome 13q that each contain a neocentromere.
Neocentromeres are fully functional centromeres that have arisen in previously noncentromeric chromosomal locations on rearranged chromosomes. The formation of neocentromeres results in the mitotic stability of chromosomal fragments that do not contain endogenous centromeres and that would normally be lost. Here we describe a unique collection of eight independent patient-derived cell lines, each of which contains a neocentromere on a supernumerary inversion duplication of a portion of human chromosome 13q. Findings in these patients reveal insight into the clinical manifestations associated with polysomy for portions of chromosome 13q. The results of FISH and immunofluorescent analysis of the neocentromeres in these chromosomes confirm the lack of alpha-satellite DNA and the presence of CENtromere proteins (CENP)-C, -E, and hMAD2. The positions of the inversion breakpoints in these chromosomes have been placed onto the physical map of chromosome 13, by means of FISH mapping with cosmid probes. These cell lines define, within chromosome 13q, at least three distinct locations where neocentromeres have formed, with five independent neocentromeres in band 13q32, two in band 13q21, and one in band 13q31. The results of examination of the set of 40 neocentromere-containing chromosomes that have thus far been described, including the 8 neocentromere-containing chromosomes from chromosome 13q that are described in the present study, suggest that chromosome 13q has an increased propensity for neocentromere formation, relative to some other human chromosomes. These neocentromeres will provide the means for testing hypotheses about sequence requirements for human centromere formation.
Functional analysis of the C-terminal region of recombinant human thrombopoietin. C-terminal region of thrombopoietin is a "shuttle" peptide to help secretion.
Thrombopoietin (TPO) is a cytokine that primarily stimulates megakaryocytopoiesis and thrombopoiesis. TPO has a unique C-terminal tail peptide of about 160 amino acids that consists mostly of hydrophilic residues and contains six N-linked sugar chains. In order to investigate the biological function of the C-terminal domain, two series of mutations were performed. One is systematic truncation from the C terminus. Another is elimination of N-glycosylation sites in the C-terminal domain by Asn to Gln mutations. After the mutant proteins were expressed by mammalian cells, it was found that the elimination of the N-linked sugar sites did not affect the biological activity, whereas truncation of the C-terminal domain resulted in elevation of in vitro activity up to 4-fold. The C-terminal peptide itself was found to inhibit the in vitro activity. Moreover, both the C-terminal truncation and the elimination of the N-glycosylation sites decreased the secretion level progressively down to (1)/(10) that of wild type, and the amount of the mutant left in the cell increased. The N-glycosylation in the C-terminal region was found to be important for secretion of TPO. Among six N-glycosylation sites in the C-terminal region, two locations, Asn-213 and Asn-234, were found to be critical for secretion, and two other locations, Asn-319 and Asn-327, did not affect the secretion.
PEBP2alphaA/CBFA1 mutations in Japanese cleidocranial dysplasia patients.
Cleidocranial dysplasia (CCD) is an autosomal dominant human bone disease whose genetic locus has been located on chromosome 6p21, where the PEBP2alphaA/CBFA1 gene essential for osteogenesis also maps. Previously, several heterozygous mutations in PEBP2alphaA/CBFA1 were found in CCD patients. In this study, we identified six different types of mutations in PEBP2alphaA/CBFA1 in Japanese CCD patients. Four cases were similar to those reported previously: two were nonsense mutations in the Runt domain, one was a hemizygous deletion, and the other was a missense mutation in the Runt domain which abolished the DNA-binding activity of Runx2/PEBP2alphaA/CBFA1. The remaining two mutations were novel: one had a heterozygous gt-to-tt mutation at the splice donor site (gt) between the exon3-intron junction, which resulted in abnormal exon3 skipping, and the other had a mutation in exon7, which led to the introduction of a translational stop codon in the middle of the transactivation domain. Thus, defects in either the DNA-binding domain or transactivation domain of Runx2/PEBP2alphaA/CBFA1 can cause CCD. The results not only provide a strong genetic evidence that mutations involving in PEBP2alphaA/CBFA1 contribute to CCD, but also provide a useful tool to study how Runx2/PEBP2alphaA/CBFA1 plays its pivotal role during osteoblastic differentiation.
A soluble transforming growth factor beta receptor expressed in muscle prevents liver fibrogenesis and dysfunction in rats.
We demonstrated that local expression of a dominant-negative type II TGF-beta receptor prevents live fibrogenesis and dysfunction in dimethylnitrosamine-treated rats. Using the same model, we have now tested whether a soluble TGF-beta receptor expressed in skeletal muscle can effectively suppress TGF-beta signaling in a remote organ (the liver). We constructed an adenovirus expressing an entire ectodomain of human TGF-beta type II receptor fused to the Fc portion of human IgG (AdTbeta-ExR). This soluble receptor secreted from AdTbeta-ExR-infected cells bound TGF-beta and blocked TGF-beta-signaling in vitro. After intramuscular injection of AdTbeta-ExR in rats, the soluble receptor protein was detectable in the blood for at least 3 weeks. When such rats were treated with dimethylnitrosamine, liver fibrosis was markedly attenuated without apparent systemic or local side effects. The hepatic hydroxyproline content was reduced to a level indistinguishable from that achieved by local expression of the dominant-negative TGF-beta receptor. Since a qualitatively and quantitatively similar suppression was achieved by the two methods, it may be concluded that the new strategy can achieve a complete inhibition of TGF-beta signaling under pathophysiological conditions in vivo. This strategy should facilitate clarification of the role of TGF-beta in vivo in various organs where direct gene transfer seems to be difficult.