Biomedical subjects

H Ohashi

Publications and source records attributed to H Ohashi.

At least 271 records · Page 15Linked to original sources

PubMed1995

Del(12)(p11.21p12.2) associated with an asphyxiating thoracic dystrophy or chondroectodermal dysplasia-like syndrome.

We describe a 5-year-old Japanese boy who has some radiographic findings characteristic of asphyxiating thoracic dystrophy (ATD)-chondroectodermal dysplasia with a de novo chromosome abnormality. He also has mild mental retardation, short stature, hypoplastic hair and skin, oligodontia, small thoracic cage, hypoplastic pelvis and cone-shaped epiphyses of hands. On cytogenetic studies he was found to have a de novo del(12)(p11.21p12.2). These results suggest that the locus of the gene associated with ATD-chondroectodermal dysplasia may be situated at 12p11.21p12.2.

Child, Preschool↗

PubMed1995

Recombinant human megakaryocyte growth and development factor (rHuMGDF), a ligand for c-Mpl, produces functional human platelets in vitro.

Platelet formation, occurring from bone marrow or lung megakaryocytes, has been difficult to study mechanistically. Recombinant human megakaryocyte growth and development factor (rHuMGDF), a recently described cytokine, has now been used to establish an in vitro system in which this important and little understood process occurs. CD34+ cells cultured with rHuMGDF develop into megakaryocytes which form long cytoplasmic extensions (proplatelets) that fragment into platelet-sized particles (in vitro platelets). Morphologically, in vitro and human plasma-derived platelets (control platelets) are virtually identical with respect to size, dense granule distribution and ultrastructural features. Functionally, in vitro and control platelets have similar aggregation and activation responses, and similarly incorporate mepacrine into dense granules. These findings suggest that rHuMGDF is sufficient to generate platelet-synthesizing megakaryocytes from CD34+ cells and provide an experimental setting in which the study of human platelet formation can be adequately performed.

Adenosine Diphosphate↗

PubMed1995

Up-regulation of integrin alpha 5 beta 1 expression by interleukin-6 in rabbit corneal epithelial cells.

Interleukin-6 (IL-6) has been shown to promote the attachment of rabbit corneal epithelial cells to fibronectin-coated substratum and ex vivo migration of the cells on the corneal stroma. To examine whether IL-6 promotes cell attachment through up-regulation of expression of integrin alpha 5 beta 1, i.e., the major cell surface fibronectin receptor, we quantified the levels of both alpha 5 and beta 1 subunit transcripts by reverse transcription-polymerase chain reaction in cultured rabbit corneal epithelial cells pretreated with various concentrations of IL-6. The levels of both alpha 5 and beta 1 mRNAs were dose-dependently elevated by IL-6, attaining 1.5- and 1.8-fold increases, respectively, at 10 ng/ml. The stimulatory effect of IL-6 was transient; the levels of both subunit mRNAs reached a maximum 1 h after the addition of IL-6 and returned to the basal levels after 6 h. The IL-6-induced up-regulation of integrin alpha 5 and beta 1 mRNAs was also confirmed by Northern blot analysis. These results indicate that the increased attachment of corneal epithelial cells to fibronectin and enhanced ex vivo migration on corneal stroma by IL-6 is, at least in part, due to the temporal up-regulation of integrin alpha 5 beta 1 expression in corneal epithelial cells.

Amino Acid Sequence↗

PubMed1995

Frequency of a 22q11 deletion in patients with conotruncal cardiac malformations: a prospective study.

Recent molecular studies have revealed that a 22q11 deletion is frequently detected in DiGeorge syndrome (DGS), velo-cardio-facial syndrome (VCFS), and conotruncal anomaly face syndrome (CTAFS). As one of the major clinical manifestations in these three syndrome is conotruncal cardiac malformation, we prospectively studied the frequency of a 22q11 deletion in a group of patients with conotruncal cardiac malformation. Fluorescence in situ hybridization (FISH) analyses using N25 (D22S75) DiGeorge Chromosome Region probe were performed on 64 patients with conotruncal cardiac malformation, who visited our clinic from October 1993 to January 1994. Of the 64 patients studied, a 22q11 deletion was detected in 5 patients (7.8%): 3 out of 30 patients with tetralogy of Fallot, one of three with interruption of the aortic arch, and one hemitruncus patient. No deletion was found in 16 patients with complete transposition of the great arteries, 8 with double outlet right ventricle and 2 with aortopulmonary window. In these five patients with 22q11 deletion, patient 1 was clinically diagnosed as having DGS, patients 2 and 3 had CTAFS, and patient 4 had VCFS. Patient 5 could not be dysmorphologically evaluated. It was noteworthy that all patients with a 22q11 deletion, except a non-evaluated patient, had some symptoms DGS, CTAFS or VCFS, and that we failed to identify a non-syndromic 22q11 deletion positive patients in the present series' of 64 patients. Conclusion. This study suggests that it is advisable to bear 22q11 deletion in mind when a patient with conotruncal cardiac anomalies has some other features of DGS, VCFS or CTAFS.

Abnormalities, Multiple↗

PubMed1995

The production of recombinant human erythropoietin.

Erythropoietin (EPO) is the glycoprotein hormone that promotes differentiation of erythroid progenitor cells in bone marrow. The normal kidney produces EPO to maintain erythrocyte for oxygen supply. This hormone activity was found in the serum of anemic animals in the 1890s. Renal failure results in severe anemia because of reduced EPO production, therefore anemia patients expected EPO treatment for long time. However, this was difficult due to the limited amount of EPO. Many researchers have tried to isolate EPO since the 1950s. Finally Miyake and Goldwasser purified highly active EPO from the urine of aplastic anemia patients. Since then, the characteristics and structural information from the purified material accelerated the cloning of the EPO gene. Mammalian cells were essential to produce EPO, because EPO contains 40% carbohydrate that plays some important roles in its activity, stability and biosynthesis. In 1984, two groups succeeded in cloning the EPO gene and expressing this gene in mammalian cells. Recombinant human EPO is currently available for anemia treatment. In this paper, we review production in mammalian cells, molecular characterization, especially carbohydrate moieties, and clinical applications of recombinant EPO.

Amino Acid Sequence↗

PubMed1995

Mutations in FGFR1 and FGFR2 cause familial and sporadic Pfeiffer syndrome.

Pfeiffer syndrome (PS) is an autosomal dominant skeletal disorder which affects the bones of the skull, hands and feet. Previously, we have mapped PS in a subset of families to chromosome 8cen by linkage analysis and demonstrated a common mutation in the fibroblast growth factor receptor-1 (FGFR1) gene in the linked families. Here we report a second locus for PS on chromosome 10q25, and present evidence that mutations in the fibroblast growth factor receptor-2 (FGFR2) gene on 10q25 cause PS in an additional subset of familial and sporadic cases. Three different point mutations in FGFR2, which alter the same acceptor splice site of exon B, were observed in both sporadic and familial PS. In addition, a T to C transition in exon B predicting a cysteine to arginine substitution was identified in three sporadic PS individuals. Interestingly, this T to C change is identical to a mutation in FGFR2 previously reported in Crouzon syndrome, a phenotypically similar disorder but one lacking the hand and foot anomalies seen in PS. Our results highlight the genetic heterogeneity in PS and suggest that the molecular data will be an important complement to the clinical phenotype in defining craniosynostosis syndromes.

Abnormalities, Multiple↗

PubMed1995

Purification and characterization of rat brain transglutaminase.

Transglutaminase (TGase) catalyzes an acyl-transfer reaction between peptidyl glutamine residues and primary amines including the epsilon-amino group of lysine residues in protein. TGase in the neuronal system has been suggested to be involved in neurotransmitter release, long-term potentiation, and so forth. In order to study the mammalian brain TGase at the molecular level, TGase was purified to apparent homogeneity from Sprague-Dawley rat brain, using DEAE ion exchange, and heparin and alpha-casein affinity column chromatographies. The brain TGase was concentrated 11,400-fold and had a specific activity of 11,000 nmol/h/mg protein. The purified protein migrated on SDS-PAGE to a position corresponding to a molecular size of approximately 75 kDa. The brain TGase activity was Ca(2+)-dependent (EC50 approximately 0.28 mM), and its Km values for putrescine and N,N-dimethylcasein were 0.26 and 0.065 mM, respectively. GTP inhibited the brain enzyme activity 100-fold more potently than ATP did, and the enzyme was photolabeled with [alpha-32P]8-azido-GTP, suggesting that the brain TGase is a member of the GTP-binding protein family. Monoiodo-acetate and cystamine potently inhibited the enzyme activity, suggesting that cysteine residue(s) are essential for brain TGase. Zn2+ inhibited the enzyme, while Mg2+ was not inhibitory. The rat brain TGase reacted only weakly with monoclonal and polyclonal antibodies against tissue-type TGase such as guinea pig liver TGase and human red blood cell TGase, while it did not react with antibodies against non-tissue types of TGase, namely human epidermal TGase and human coagulation factor XIIIa. The results suggest that rat brain TGase shares major characteristics with tissue-type TGase, but is nevertheless distinct from tissue-type TGase.

Affinity Labels↗

PubMed1995

Megakaryocyte growth and development factor. Analyses of in vitro effects on human megakaryopoiesis and endogenous serum levels during chemotherapy-induced thrombocytopenia.

The present study shows that recombinant human megakaryocyte growth and development factor (r-HuMGDF) behaves both as a megakaryocyte colony stimulating factor and as a differentiation factor in human progenitor cell cultures. Megakaryocyte colony formation induced with r-HuMGDF is synergistically affected by stem cell factor but not by interleukin 3. Megakaryocytes stimulated with r-HuMGDF demonstrate progressive cytoplasmic and nuclear maturation. Measurable levels of megakaryocyte growth and development factor in serum from patients undergoing myeloablative therapy and transplantation are shown to be elaborated in response to thrombocytopenic stress. These data support the concept that megakaryocyte growth and development factor is a physiologically regulated cytokine that is capable of supporting several aspects of megakaryopoiesis.

Adult↗

PubMed1995

Possible involvement of a small G-protein sensitive to exoenzyme C3 of Clostridium botulinum in the regulation of myofilament Ca2+ sensitivity in beta-escin skinned smooth muscle of guinea pig ileum.

The effects of exoenzyme C3 of Clostridium botulinum on Ca(2+)- and drug-induced tension developments were investigated in beta-escin skinned smooth muscle of guinea pig ileum to test the involvement of a small G-protein in the regulation of myofilament Ca2+ sensitivity. C3 is known to ADP-ribosylate the rho p21 family of small G-proteins. Treatment with C3 (0.35 microgram/ml, for 30 min) shifted the pCa-tension curve rightward along the Ca2+ concentration axis, indicating a decrease in Ca2+ sensitivity of the contractile elements. The inhibitory effect of C3 was not preserved after treatment with GDP beta S (1 mM), an antagonist of GTP for the binding to G-proteins. Stimulation of muscarinic receptors with carbachol (CCh, 100 microM) shifted the pCa-tension curve leftward, indicating Ca2+ sensitization of tension development. The Ca(2+)-sensitizing effect of CCh was not observed after C3 treatment. When GTP gamma S (10 microM), an activator of G-proteins, was applied at a plateau of tension development produced by a moderate concentration of Ca2+, further increase in tension was elicited and the effect of GTP gamma S was inhibited by C3 treatment. The results suggest the possible involvement of a rho p21-like small G-protein in the regulation of Ca2+ sensitivity of smooth muscle myofilaments.

Animals↗

PubMed1995

Ras amplification in BHK-21 cells produces a host cell line for further rapid establishment of recombinant protein hyper-producing cell lines.

To rapidly establish recombinant protein hyper-producing cell lines we introduced a reporter plasmid into BHK-21 cells that had been 'primed' by transfection and amplification of the ras oncogene. The reporter plasmid used carries the human interleukin-6 (hIL-6) gene which is under control of the human cytomegalovirus immediate early promoter. The primed BHK cell lines were shown to produce many stable hIL-6 hyper-producing cells achieving about 15 times higher productivity than the control BHK-21 cells.

Animals↗

PubMed1995

E1A and ras oncogenes synergistically enhance recombinant protein production under control of the cytomegalovirus promoter in BHK-21 cells.

The amplified ras oncogene greatly enhanced the production of recombinant human interleukin-6 (hIL-6) under control of the cytomegalovirus immediate early promoter (CMV promoter) in BHK-21 cells. When the adenovirus E1A oncogene was further transfected into the above mentioned ras-amplified hIL-6 hyperproducing BHK cells, the transfectants had about 10 times higher productivity than non-transfectants. However, the E1A gene alone did not enhance productivity. These results implicate a ras and E1A synergistic ability that acts to enhance hIL-6 production.

Adenoviridae↗

PubMed1995

Treatment with triiodothyronine (T3) against multinodular goiter fails to prevent the onset of Graves' disease.

We report two cases who developed hyperthyroidism and positive thyroid stimulating antibody (TSAb) while they were treated with T[3] under the diagnosis of follicular adenoma of thyroid for four or eleven years, respectively. In both cases thyroid scintigraphy revealed an increased radioiodine uptake with multinodular defects. The uptake of 131I was not suppressed by the administration of T[3]. Histological examination showed encapsulated nodule surrounded by diffuse hyperplasia. TBII or TSAb appeared in accordance with increased plasma levels of T[3] and T[4]. In spite of suppressed TSH the appearance of TSAb and subsequent manifestations of Graves' disease suggested that T[3] failed to prevent the immune mechanism which was involved in the production of TSAb.

Journal Article↗

PubMed1995

[A case of Ebstein's anomaly treated by tricuspid valve replacement].

A 8-year-old girl with Ebstein's anomaly was operated on because of progressive heart failure caused by severe tricuspid regurgitation. At the operation, the tricuspid leaflets were found to be destroyed, and the annulus was very enlarged. The enlarged true tricuspid annulus was constricted using the DeVega method, and the tricuspid valve was replaced on the true annulus using a porcine valve. To avoid injury to the auriculoventricular bundle, the suture line was shifted to the false annulus at the portion close to the course of His' bundle. Postoperative course was uneventful in satisfactory condition. The role of valve replacement in the treatment of Ebstein's anomaly of the tricuspid valve is not only to improve valve formation, but also to secure the function of the right ventricle. It is ideal to replace the tricuspid valve on the true annulus provided that the injury to the His' bundle is safely avoided.

Child↗

PubMed1995

[Analysis of Fas and bcl-2 expression on peripheral blood lymphocytes from primary Sjögren's syndrome].

The Fas antigen is the major trigger for apoptosis. In MRL/lpr mice, defects in Fas expression lead to autoimmunity and lymphoid accumulation, same as in the Sjögren's syndrome (SS). Bcl-2 protein is able to repress a number of apoptotic death. Therefore, we examined both Fas antigen and bcl-2 expression in peripheral blood lymphocyte (PBL) from SS patients. The rate of Fas+CD4+ PBL was significantly elevated (p < 0.01) in SS patients (n = 11) compared to normal controls (n = 15). Both Fas+CD3+ and Fas+CD8+ cells from SS patients showed a tendency to increase, whereas Fas+B cell was not different between each group. The percentages of bcl-2+ lymphocytes in SS patients were no different compared to the normal control. This study suggests that the increased expression of Fas may result in enhanced susceptibility to apoptosis.

Animals↗

PubMed1995

Radiological changes of frontometaphyseal dysplasia in the neonate.

The radiological manifestation of frontometaphyseal dysplasia has been well elucidated in later childhood and adulthood, but it has not been thoroughly clarified in the neonate. Here we report the radiological features of a neonate with frontometaphyseal dysplasia. Most features, including twisted ribs, increased interpediculate distances of the lumbar spine, flared ilia, mildly flared and bowed long bones, and arachnodactyly with undermodeled short tubular bones, were reminiscent of those found in older children and adults. A previously undescribed abnormality was advanced ossification of the femoral and tibial epiphyses.

Abnormalities, Multiple↗

PubMed1995

Clinical effect of etidronate disodium (EHDP) on heterotopic ossification following total hip arthroplasty.

We investigated the status of the development of heterotopic ossification and compared the frequency of heterotopic ossification in the EHDP group with that in the untreated (control) group to evaluate the efficacy and safety of EHDP. Seventy-seven patients who had undergone total hip arthroplasty or femoral head prosthesis for the treatment of osteoarthritis and femoral neck fracture were enrolled in the study. Heterotopic ossification surrounding the hip joint was evaluated according to the roentgenographic classification. In the control group, heterotopic ossification was found in 10 patients (20%) during the period, while in the EHDP group, it was found in one patient (3.7%) during the treatment period after the operation. Gastrointestinal disorder, in one case only was a side effect observed during EHDP treatment. It was revealed that EHDP inhibits heterotopic ossification following total hip replacement in patients with osteoarthritis.

Adult↗

PubMed1994

Multiple proline substitutions cumulatively thermostabilize Bacillus cereus ATCC7064 oligo-1,6-glucosidase. Irrefragable proof supporting the proline rule.

Nine residues of Bacillus cereus ATCC7064 oligo-1,6-glucosidase were replaced stepwise with proline residues. Of the nine residues, Lys121, Glu208 and Glu290 were at second sites of beta turns; Asn109, Glu175 and Thr261 were at N-caps of alpha helices; Glu216, Glu270 and Glu378 were in coils within loops. The replacements were carried out in the order, Lys121-->Pro, Glu175-->Pro, Glu290-->Pro, Glu208-->Pro, Glu270-->Pro, Glu378-->Pro, Thr261-->Pro, Glu216-->Pro and Asn109-->Pro. The resultant nine active mutant enzymes contained 1-9 more proline residues than B. cereus oligo-1,6-glucosidase. The thermostability of these mutants was additively enhanced with the increase in the number of proline residues introduced. The increase in the thermostability was most remarkable when proline residues were introduced at second sites of beta turns or at N-caps of alpha helices. The above results afforded irrefragable proof for the proline rule as an effective principle for increasing protein thermostability [Suzuki, Y., Oishi, K., Nakano, H. & Nagayama, T. (1987) Appl. Microbiol. Biotechnol. 26, 546-551].

Amino Acid Sequence↗

PubMed1994

Ca2+ inhibition of inositol trisphosphate-induced Ca2+ release in single smooth muscle cells of guinea-pig small intestine.

1. Single smooth muscle cells from the longitudinal muscle layer of guinea-pig small intestine were voltage clamped using patch pipettes in the whole-cell mode. 2. When D-myo-inositol 1,4,5-trisphosphate (InsP3) was released at intervals, by photolysis of 'caged' InsP3 within the cell, increases in [Ca2+]i in many cells, as judged from Ca(2+)-activated K(+)-current, were all-or-none; release of InsP3 before a critical interval had elapsed, which was quite stable for an individual cell, resulted in no response. After Ca(2+)-induced Ca2+ release had been evoked by depolarization, the InsP3 response was inhibited. Oscillations in [Ca2+]i evoked by muscarinic receptor activation were unaffected by Ruthenium Red; during these oscillations exogenous InsP3 was not effective close to, or shortly after, peak [Ca2+]i but was effective at other times. 3. Reproducible release of Ca2+ and elevation of [Ca2+]i could be produced by brief (up to 0.5 s) pressure applications of 10 mM caffeine at intervals of 10 s or greater but caffeine itself rarely evoked oscillations in [Ca2+]i. Responses to flash release of InsP3 were reduced after caffeine-induced responses and recovery of caffeine-induced Ca2+ release was faster than recovery of InsP3-induced Ca2+ release. 4. The results support the idea that InsP3-induced Ca(2+)-store release can be inhibited by a certain level of [Ca2+]i at a time when Ca2+ stores have refilled and can be released by caffeine; they also support the suggestion that during oscillations of [Ca2+]i evoked by muscarinic receptor activation, Ca2+ inhibition of InsP3-induced Ca2+ release at some critical level of [Ca2+]i allows Ca2+ stores to refill and leads to a fall in [Ca2+]i so contributing to the oscillations which are observed.

Animals↗