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H Ohashi

Publications and source records attributed to H Ohashi.

At least 145 records · Page 8Linked to original sources
PubMed1999

Cartilaginous differentiation in the joint capsule.

The proliferation and differentiation of cells are greatly influenced by their environment. Many growth factors and cytokines are reported to be environmental factors that affect the proliferation and differentiation of cells. Mechanical stress is also considered to influence these physiological reactions. The joint capsule, which is a part of the joint tissue, plays a very important role in the stability of the joint and in maintaining the intracapsular phenomenon. In patients with dislocated hip arthropathy, this capsule is involved in the weightbearing function by forming a sliding surface between the capsule and the femoral head articular cartilage. The surface of the tissue macroscopically shows cartilaginous change, which indicates cartilaginous differentiation caused by mechanical stress. We examined the cartilage-specific proteoglycan component, which is composed of cartilaginou matrix at the differentiation site. We investigated proteoglycan production, molecular size, and the gene expression of cartilaginous substrate. At the inner layer of the weightbearing area of the joint capsule, proteoglycan production was significantly higher than that of other noncartilaginous tissue. We also identified the gene expression of cartilaginous proteoglycan using the reverse transcription polymerase chain reaction (RT-PCR) method.

Aggrecans↗
PubMed1999

Radial-sequence magnetic resonance imaging in evaluation of acetabular labrum.

We investigated the usefulness of a radial-sequence magnetic resonance imaging (MRI) technique in the visualization of the acetabular labrum, which surrounds the acetabulum. In 22 hip joints of 12 volunteers, T2-weighted images were obtained on 24 radial planes of the acetabular rim, set at 15 degrees -intervals, using the small tip angle gradient echo method. We examined 7 planes in the weight-bearing portion. The acetabular labrum in the weight-bearing portion was depicted in good contrast to the surrounding tissues. The shape of the labrum differed among individuals and also in the anterior and posterior portions of the labrum. The signal intensity of the labrum was low or partially moderate. There was a high signal intensity band on the base of the acetabular labrum in several portions, which should be carefully interpreted to avoid confusion with abnormality. We concluded that radial-sequence MRI could be a useful technique for evaluation of the condition of the acetabular labrum in the weight-bearing portion.

Acetabulum↗
PubMed1999

Four novel mutations of the Fanconi anemia group A gene (FAA) in Japanese patients.

Fanconi anemia (FA) is an autosomal recessive disorder characterized by pancytopenia, predisposition to cancers, and a diverse variety of congenital malformations. At least eight complementation groups, A through H, have been described. Recently, the FA-A gene (FAA) has been isolated, and a large number of distinct mutations reported in ethnically diverse FA-A patients. Here, we report on the mutation analysis of five FA patients by single-strand conformation polymorphism. Out of five patients, at least three were found to have mutations in the FAA gene. The first patient was a compound heterozygote with a 1-bp deletion and a single-base substitution. The second patient had a heterozygous 2-bp deletion, which introduces a premature termination codon, and the third patient had a heterozygous splice donor site mutation in intron 27.

Base Sequence↗
PubMed1999

Thrombopoietin induces an SH2-containing protein, CIS1, which binds to Mpl: involvement of the ubiquitin proteosome pathway.

The interaction of thrombopoietin (TPO) with its receptor, Mpl, triggers growth and differentiation of megakaryocytes and their progenitors. The Mpl cytoplasmic domain controls this process through src homology 2 (SH2)-containing target molecules and their receptor docking sites. A novel cytokine inducible SH2-containing protein, CIS1, has been isolated. CIS1 is induced by interleukin-2 (IL-2), IL-3, GM-CSF, and erythropoietin (EPO), but not by IL-6, granulocyte colony-stimulating factor (G-CSF), or stem cell factor. To investigate the functional domains of Mpl for induction of CIS1, we examined FDCP-2 cell lines expressing seven carboxyl truncations of the human Mpl cytoplasmic domain. We found that the box1 and box2 regions of Mpl were necessary for induction of CIS1 after TPO stimulation. CIS1 was degraded very quickly and was found to be involved in the ubiquitin-proteosome pathway. A 4-hour depletion of TPO almost completely eliminated CIS1 protein; within 1 hour after TPO stimulation, CIS1 protein reappeared as 37- and 32-kDa proteins in the wild type Mpl-expressing FDCP-2 cells. Further, CIS1 was stably associated with tyrosine-phosphorylated Mpl. The SH2 domains of CIS1, constructed as glutathione S-transferase fusion protein, bound to activated Mpl in vitro. These results suggest that CIS1 may be an important signaling component downstream of Mpl and may regulate the proliferation and differentiation of hematopoietic cells.

Animals↗
PubMed1999

Determination of mechanical properties of impacted human morsellized cancellous allografts for revision joint arthroplasty.

This paper deals with the characterization of mechanical properties of impacted morsellized cancellous allograft (IMCA) produced by dynamic compaction of allograft femoral heads ground by commercially available bone mills, i.e. rotating rasp and reciprocating type bone mills. Various ranges and profiles of particle size in the graft aggregates were obtained using these bone mills, and the effect of number of compaction as well as the distribution of particle sizes on the mechanical properties of IMCA under quasistatic compression and shear loading conditions was discussed. The morsellized cancellous allograft prepared by the reciprocating type bone mill showed a broad distribution of particle sizes, and gave IMCA superior mechanical properties to the graft with a more uniform size distribution, or prepared by the rotating rasp type bone mills. The increase of number of compaction also improved the mechanical properties of IMCA in compression.

Journal Article↗
PubMed1999

Cloning of translocation breakpoints associated with Shwachman syndrome and identification of a candidate gene.

Shwachman syndrome is an autosomal-recessive disorder characterized by exocrine pancreatic insufficiency, bone-marrow dysfunction, and metaphyseal chondrodysplasia. A de novo balanced translocation was recently documented in a patient with this disease. Toward isolating the gene(s) responsible for Shwachman syndrome, we cloned and sequenced the translocation breakpoints in the DNA of this patient. The nucleotide sequences around the breakpoints contained neither repetitive elements nor motifs reported to be implicated in recombination events, although we did detect gains or losses of oligonucleotides at the translocation junctions. By large-scale genomic sequencing and in silico gene trapping, we identified two novel transcripts in the vicinity of the breakpoints that might represent candidate genes for Shwachman syndrome, one on chromosome 6 and the other on chromosome 12. The gene on chromosome 12 was actually disrupted by the translocation.

Amino Acid Sequence↗
PubMed1999

Modification of membrane currents in mouse neuroblastoma cells following infection with rabies virus.

1. The effect on membrane currents of infection of mouse neuroblastoma NA cells with rabies virus was studied by using the whole-cell patch clamp technique. 2. Three types of membrane currents, namely voltage-dependent Na+ current (I(Na)), delayed rectifier K+ current (I(K-DR)) and inward rectifier K+ current (I(K-IR)) were elicited in uninfected cells. 3. In cells 3 days after infection with the virus, no detectable change was observed in morphology and membrane capacitance, but I(Na) and I(K-IR) were significantly decreased in amplitude without any appreciable difference in the time course of current activation and inactivation. The voltage-dependence of I(Na) activation was significantly shifted in the positive direction along the voltage axis with a decreased slope. I(K-DR) remained almost unaltered after the viral infection. 4. The resting membrane potential, measured with a physiological K+ gradient across the cell membrane, was decreased (depolarized) after the viral infection. The depolarization was associated with the decreased amplitude of I(K-IR). 5. These results suggest that infection of mouse neuroblastoma NA cells with rabies virus causes reduction of functional expression of ion channels responsible for I(Na) and I(K-IR), and provide evidence for possible involvement of the change in membrane properties in the pathogenesis of rabies disease.

Animals↗
PubMed1999

Microtubule cytoskeleton involvement in muscarinic suppression of voltage-gated calcium channel current in guinea-pig ileal smooth muscle.

1. Effects of agents, which affect microtubule polymerization-depolymerization cycle, on Ba2+ current (IBa) flowing through voltage-gated Ca2+ channels and carbachol (CCh)-induced sustained suppression of IBa were examined in whole-cell voltage-clamped smooth muscle cells of guinea-pig ileum. 2. offchicine (100 microM) and vinblastine (100 microM), microtubule depolymerizers, increased the ampitude of IBa. Lumicolchicine (100 microM), an inactive analogue of colchicine, had no effect on IBa. 3. Taxol (1 - 100 microM), a microtubule polymerizer, decreased IBa in a concentration-dependent manner and accelerated the rate of inactivation of IBa. Baccatin III (100 microM), an inactive analogue of taxol, had no effect on IBa. 4. Colchicine (100 microM) and vinblastine (100 microM), but not lumicolchicine (100 microM), decreased or abolished the sustained component of CCh (10 microM)-induced IBa suppression. 5. Pretreatment with taxol (10 - 100 microM) resulted in a concentration-dependent decrease in IBa and the action of CCh on IBa. The inhibitory effects of taxol and CCh on IBa were not additive. 6. Colchicine (100 microM) or taxol (100 microM) had no effect on voltage-gated K+ channel current or CCh-induced non-selective cationic channel current. 7. These results suggest that polymerization of microtubules leads to suppression of Ca2+ channel activity, and that muscarinic sustained suppression of Ca2+ channel current is mediated by a signal transduction element which involves microtubule cytoskeleton.

Animals↗
PubMed1999

Clonality analysis of refractory anemia with ring sideroblasts: simultaneous study of clonality and cytochemistry of bone marrow progenitors.

X chromosome inactivation and polymorphism of the human androgen receptor (HUMARA) gene has been applied for analyzing the clonality of blood cells. In the present study, the clonal relationship was investigated between peripheral blood polymorphonuclear cells (PMNCs) and marrow progenitor cells and the origin of ringed sideroblasts in patients with refractory anemia with ring sideroblasts (RARS) by polymerase chain reaction (PCR) of HUMARA gene. The X-inactivation patterns of circulating PMNCs and T lymphocytes as well as individual granulocyte colonies grown in vitro from bone marrow cells were analyzed. The development of ringed sideroblasts in erythroid colonies by iron staining and their X-inactivation pattern were also examined. All three RARS patients showed monoclonal PMNCs. In granulocyte colonies, however, two different X-inactivation patterns were observed in all patients, indicating that non-clonal progenitor cells remained in the bone marrow. All erythroid colonies consisted of ringed sideroblasts exclusively showed one pattern dominant in those of PMNCs. Our findings suggest that non-clonal progenitor cells persist in some RARS cases, that erythroid progenitors show mosaicism, and that ringed sideroblasts may be derived from an abnormal clone involved in the pathogenesis of this disease.

Aged↗
PubMed1999

Lipoprotein(a) as a risk factor for coronary artery disease in hemodialysis patients.

BACKGROUND: We studied whether lipoprotein(a) [Lp(a)] is an independent risk factor for coronary artery disease (CAD) in hemodialysis (HD) patients. METHODS: A serum concentration of Lp(a) was measured in 212 patients with chronic glomerulonephritis and 56 patients with diabetic nephropathy (a total of 268 patients). The causes of death during five years of follow-up were studied and classified into either cardiovascular or noncardiovascular events. RESULTS: The mortality of these 268 HD patients during the observation period was 26.1%. Seventy-eight percent were due to cardiovascular events. Those who died of cardiovascular events had significantly higher serum Lp(a) levels than those died of noncardiovascular events. The relative risk of death from CAD was 0.71 in HD patients with a Lp(a) concentration above 30 mg/dl. CONCLUSIONS: This study indicates that the serum Lp(a) levels are independent indicators of the future risk of death from CAD in HD patients.

Adult↗
PubMed1999

Visual impairment and REP-1 gene mutations in Japanese choroideremia patients.

Choroideremia (CHM), an X-linked recessive hereditary disease, is an intractable chorioretinal dystrophy. The rate of disease progression of CHM reportedly shows considerable variability. A number of mutations involving the gene that codes for Rab escort protein-1 (REP-1) have been detected in CHM patients. We have analyzed REP-1 gene mutations of Japanese CHM patients. The present study was designed to investigate the clinical variability and the genotype to phenotype relationship in 15 Japanese CHM patients referred to the Department of Ophthalmology of Juntendo University Hospital. The clinical investigation of visual acuity, visual field, color vision and refraction revealed inter-individual variability. Mutation analyses of the REP-1 gene revealed 10 types of mutations in 13 patients from 11 families, including an insertion, small deletions, nonsense mutations and an A to CC mutation. In 13 CHM patients with detectable REP-1 gene mutations, no relationship of genotype to phenotype was detected. At present, we consider the REP-1 genotype to be an unreliable prognostic factor for counseling of CHM patients. In two patients from one family, no mutations were detected in coding regions of the REP-1 gene. These patients may have intron mutations of the REP-1 gene, not detectable by the techniques employed in this study, or other causative genes. Both were observed to have somewhat slower disease progression than the other 13 patients. More advanced analyses are necessary to answer questions regarding the genotype-phenotype relationship in CHM patients.

Adaptor Proteins, Signal Transducing↗
PubMed1999

Effect of interleukin-3, interleukin 5 and hyaluronic acid on cultured eosinophils derived from human umbilical cord blood mononuclear cells.

BACKGROUND: Several studies have shown that cultured eosinophils can be generated from human umbilical cord blood mononuclear cells (UCMC) in the presence of interleukin (IL)-3 and IL-5 in vitro. Other reports have indicated that cellular adhesion to hyaluronic acid (HA) enhances the proliferation of cultured eosinophils derived from CD34+ cells purified from UCMC. The aim of this study was to obtain large numbers of mature eosinophils from UCMC using IL-3, IL-5 and HA, and to investigate their functions. METHODS: We examined several combinations of IL-3 and IL-5 and their effect on eosinophil development from UCMC in HA-coated on non-coated flasks. We also examined whether cultured eosinophils degranulated eosinophil-derived neurotoxin (EDN) induced by secretory immunoglobulin A conjugated to sepharose beads (sIgA-beads) and responded to eotaxin. RESULTS: Culture with HA-coated flasks for 35 days (in the presence of IL-3 and IL-5, with IL-3 omitted after day 14 of culture) caused a 11.2-fold augmentation in the proliferation of UCMC. On day 35 of the culture, 98% of cultured cells were eosinophils judging from May-Grünwald and Giemsa staining and transmission electron micrographs. The EDN content of the cultured eosinophils on day 35 was 156 ng/105 cells. Cultured eosinophils degranulated EDN induced by sIgA-beads and responded to eotaxin by chemotaxis and intracellular Ca2+ mobilization. CONCLUSION: We found a useful culture system to obtain large numbers of eosinophils derived from UCMC, which may facilitate the investigation of eosinophil function, since there was no significant difference in response to sIgA-beads and eotaxin between cultured and peripheral eosinophils.

Cell Degranulation↗
PubMed1999

Apoptosis and overexpression of bax protein and bax mRNA in smooth muscle cells within intimal hyperplasia of human radial arteries : analysis with arteriovenous fistulas used for hemodialysis.

There is a type of arteriosclerosis with remodeling of middle-size arteries in which intimal hyperplasia of smooth muscle cells (SMCs) plays the main role, and there are few macrophages, T lymphocytes, and foam cells. It is unknown whether apoptosis and the expression of Bax, an inducer of apoptosis, are increased according to the progression of this type of human arteriosclerosis, which is different from so-called atherosclerosis. Bax heterodimerizes with Bcl-2, an inhibitor of apoptosis, and the ratio of Bax to Bcl-2 determines cellular apoptosis or survival. Thus, we investigated apoptosis and the expressions of Bax, bax mRNA, and Bcl-2 in human arteriovenous (AV) fistulas used for hemodialysis, a representative of arteriosclerosis of the aforementioned type. The material was 20 radial arteries obtained from 20 patients with chronic renal failure undergoing AV shunt surgery. SMCs, macrophages, and T lymphocytes were immunohistochemically identified at the light microscopic (LM) level. Apoptosis was detected by in situ terminal deoxynucleotidyl transferase (TdT)-mediated digoxigenin-dUTP nick end labeling (TUNEL) at both the LM and electron microscopic (EM) level. Cell proliferating activity was estimated by proliferating cell nuclear antigen (PCNA). Bax and Bcl-2 were detected by immunohistochemistry and Western blot analysis. Expression of bax mRNA was detected by in situ hybridization. LM TUNEL-positive cells in both the intima and media were significantly increased according to the percent stenosis of the vessels. EM analysis revealed that ultrastructures of apoptotic SMCs were seen in both synthetic and contractile phenotypes. Their frequency of occurrence in the intima and media were greater in those vessels with >50% stenosis than in those with <50% stenosis (5.2+/-0.7% versus 1.0+/-0.3% in the intima and 2. 1+/-0.5% versus 0.2+/-0.1% in the media). The proportion of apoptotic SMCs with ruptured plasma membranes was greater than that of apoptotic SMCs with intact membranes in the intima of the former (4.1+/-0.6% versus 1.1+/-0.1%). Only those SMCs with apoptotic ultrastructures had TUNEL-positive nuclei with moderate or marked accumulation of immunogold particles at the EM level. However, ultrastructures of oncosis (primary necrosis) were not observed. Immunohistochemical analyses showed significant positive correlations between percent stenosis of vessels and the percentage of either PCNA-positive intimal cells or Bax-positive areas in the intima and media. Bcl-2-positive cells were not observed in the intima but mainly in the outer media. The percentage of Bcl-2-positive medial cells was definitely decreased at an early stage after formation of the AV fistula but did not change according to the duration of hemodialysis or the progression of arteriosclerosis. Western blot analysis of Bax or Bcl-2 and in situ hybridization of bax mRNA confirmed the immunohistochemical data. Thus, regulation of cellularity in intimal hyperplasia of SMCs in human arteriosclerosis with remodeling is mediated by proliferation and apoptosis but not oncosis. The apoptosis is probably induced by an increase in the Bax to Bcl-2 ratio.

Adult↗
PubMed1999

Skeletal features and growth patterns in 14 patients with haploinsufficiency of SHOX: implications for the development of Turner syndrome.

We report on clinical features in 14 Japanese patients (4 males and 10 females) with partial monosomy of the short arm pseudoautosomal region involving SHOX (n = 11) or total monosomy of the pseudoautosomal region with no involvement of disease genes on the sex-differential regions (n = 3). Skeletal assessment showed that three patients had no discernible skeletal abnormalities, one patient exhibited short 4th metacarpals and borderline cubitus valgus, and the remaining 10 patients had Madelung deformity and/or mesomelia characteristic of Léri-Weill dyschondrosteosis (LWD), together with short 4th metacarpals and/or cubitus valgus. Skeletal lesions were more severe in females and became obvious with age. Growth evaluation revealed that patients without LWD grew along by the -2 SD growth curve before puberty and showed a normal or exaggerated pubertal growth spurt, whereas those with LWD grew along by the standard growth curves before puberty but exhibited an attenuated pubertal growth spurt and resultant short stature. Maturational assessment indicated a tendency of relatively early maturation in patients with LWD. There was no correlation between the clinical phenotype and the deletion size. These findings suggest that haploinsufficiency of SHOX causes not only short stature but also Turner skeletal anomalies (such as short 4th metacarpals, cubitus valgus, and LWD) and that growth pattern is primarily dependent on the presence or absence of LWD. Because skeletal lesions have occurred in a female-dominant and age-influenced fashion, it is inferred that estrogens exert a maturational effect on skeletal tissues that are susceptible to premature fusion of growth plates because of haploinsufficiency of SHOX, facilitating the development of skeletal lesions.

Adolescent↗
PubMed1999

Evaluation of PCR as a means of identification of Pasteurella pneumotropica.

A polymerase chain reaction with new primers (new PCR) designed from Pasteurella pneumotropica 16S rDNA as an identification system for this organism was compared with the PCR reported by Wang et al. (Wang's PCR) by using 15 bacterial reference species and 70 clinical isolates with the conventional identification system. For the 15 reference strains, both PCRs were identical. For the 70 clinical isolates, the new PCR and Wang's PCR showed consistency with the conventional system in 62.9% (44/70) and 51.4% (36/70), respectively. Twenty-six isolates were inconsistent with the conventional system and the new PCR with respect to morphology and serology. These findings suggested that the new PCR was more sensitive than Wang's PCR, and the new PCR in combination with morphology and serology is useful for P. pneumotropica identification.

Animals↗
PubMed1999

[Coronary artery bypass surgery in octogenarian].

Between May 1992 and December 1997, 14 parents aged 80 or older underwent CABG with cardiopulmonary bypass. (Group A: mean age 82.1 +/- 1.73). This group was compared with 127 patients aged 70s. (Group B: mean 73.3 +/- 0.70). Left main trunk stenosis was more frequent in group A (p < 0.05), and number of patient who had old myocardial infarction was also frequent (p < 0.05). Emergency operation and preoperative use of intra aortic balloon pump was frequent in group A (p < 0.05). While there was no significant change in the number of graft per patient and used number of internal thoracic artery between the two groups, postoperative complications such as atrial arrhythmia and respiratory failure was appeared more frequently in group A (p < 0.05). The hospital mortality did not differ between the groups (21.4% for group A and 14.2% for group B). In group A, 11 patients are alive without recurrence of angina. In conclusion, while there is many problems pre and post operative term, CABG in over 80 years patients of age was satisfactory result, so we should not exclude octogenarian because of age alone.

Aged↗