Search PubMed⌕ Search

Biomedical subjects

H Ohno

Publications and source records attributed to H Ohno.

At least 343 records · Page 19Linked to original sources
PubMed1994

Effects of titanium nitride coatings on surface and corrosion characteristics of Ni-Ti alloy.

The structure of a titanium nitride film coated by arc ion plating on a Ni-50Ti shape memory alloy was characterized by X-ray photoelectron spectroscopy (XPS). The corrosion behavior of the titanium nitride-coated Ni-50Ti alloy was examined in 0.9% NaCl solution by potentiodynamic polarization measurements and a polarization resistance method. XPS spectra showed that the titanium nitride film consisted of three layers, a top layer of TiO2, a middle layer of TiNx (x > 1), and an inner layer of TiN. The passive current density for the titanium nitride-coated alloy was approximately two orders of magnitude lower than that of the polished alloy in the potential range from the free corrosion potential to +500 mV (vs. Ag/AgCl). Pitting corrosion associated with breakdown of the coated film occurred above this potential. The polarization resistance data also indicated that the corrosion rate of the titanium nitride-coated alloy at the free corrosion potential (+50-+100 mV) was more than one order of magnitude lower than that for the polished alloy.

Corrosion↗
PubMed1994

A novel angiogenesis model using interstitial cells derived from skeletal muscle.

A novel angiogenesis model using co-culture of endothelial and interstitial cells was developed, in which bovine capillary endothelial cells (BCEC) formed capillary-like structure on the monolayer of interstitial cells (like smooth muscle cells) isolated from rat skeletal muscle. The capillary formation of BCEC occurred even under serum-free conditions. Insulin stimulated the capillary growth under serum-free condition, but not BCEC growth in the single culture system. These results suggested that the insulin effect on the capillary growth was brought about indirectly through the interstitial cells, and that this co-culture system may be useful for the study of angiogenesis (especially in skeletal muscle).

Animals↗
PubMed1994

[Rapid identification of mycobacteria by combined method of polymerase chain reaction and the gen-probe DNA hybridization system].

We developed the rapid detection and identification method of mycobacteria, involving amplification of mycobacterial 16S rRNA gene by nested PCR and identification of M. tuberculosis complex or M. avium-intracellulare complex (MAC) by hybridization protection assay (HPA) using the acridinium-ester (AE) labeled DNA probe. The specificity of the nested PCR combined with DNA probe test was excellent in terms of detection of mycobacterial organisms and identification of M. tuberculosis or MAC. The detection limits of the present method were 10 fg DNA for M. tuberculosis, and 100 fg DNA for MAC, respectively. We further investigated on the optimum temperature for hybridization in HPA with AE labeled DNA probe because there was the difference in the mode of DNA-RNA hybridization from that of DNA-DNA hybridization. In our method, the optimum temperature of hybridization was estimated as 55 +/- 1 degrees C. In preliminary experiments on two clinical cases, we practically detected and identified M. tuberculosis and MAC in clinical specimens, such as sputa, by using this newly devised method. We concluded that this method is useful for rapid detection and identification of M. tuberculosis and MAC in clinical specimens.

Adult↗
PubMed1994

[Evaluation for rapid detection of rifampicin-resistant mycobacterium tuberculosis by polymerase chain reaction-single strand conformation polymorphism].

We evaluated usefulness of the rapid diagnostic method for detection of rifampicin (RFP)-resistant Mycobacterium tuberculosis, which was based on polymerase chain reaction. The MICs of RFP were measured for 38 clinical isolates of Mycobacterium tuberculosis which were suspected to be RFP-resistant organisms, and 12 strains were found to be resistant to RFP. The PCR primers used were the same as those reported by Telenti et al, which were targeting the RNA polymerase beta subunit gene (rpoB). We confirmed that this gene was possessed by all the strains tested. Eight strains out of the 12 strains with RFP-resistant phenotype were demonstrated to have a point mutation or some alterationin the rpoB gene on the basis of PCR-single strand conformation polymorphism (SSCP). Thus, the sensitivity of our method was calculated as 67%. In addition, we could not detect any alterations in the rpoB gene by all RFP-susceptible strains. These results indicated that rapid detection of the RFP-resistant Mycobacterium tuberculosis was possible directly from clinical specimens by using PCR-SSCP technique.

Base Sequence↗
PubMed1994

Is heat acclimation able to increase whole-body sensitivity to insulin?

The aim of the present study was to determine whether heat acclimation increases whole-body sensitivity to insulin. Male Wistar rats were kept at 34 degrees C for 2 weeks (HA group). Warm-acclimated rats (WA group) at 25 degrees C served as controls. The glucose infusion rate (GIR) was assessed as an index of in vivo insulin sensitivity, using a hyperinsulinemic euglycemic clamp technique. Moreover, the 125I-insulin binding capacity to purified insulin receptor preparations from m. gastrocnemius of rats after 1, 7, or 14 days of heat exposure was examined. Mean GIR values of HA group were slightly higher than those of WA group, but not significant. The great deviation of the HA group, however, appeared to exist. About half of HA rats showed markedly high GIR values (p < 0.01 vs. WA group). Mean GIR value of the remaining HA rats were significantly (p < 0.05) lower than those of the WA group. Likewise, the binding capacity to 125I-insulin was not significantly different among the periods of time of heat exposure, and the deviation went on increasing from 1 to 14 days. These results suggest that there is a wide individual difference between the changes in glucose metabolism under heat exposure. In view of such results, there appears to be a great need for further studies on the factors affecting the variation of insulin action.

Acclimatization↗
PubMed1994

Involvement of the BCL3 gene in two patients with chronic lymphocytic leukemia.

The t(14;19)(q32;q13) is a recurring translocation found in some patients with chronic lymphocytic leukemia (CLL), and the t(14;19) juxtaposes the BCL3 gene on chromosome 19 with the immunoglobulin heavy chain gene (IGH) locus on chromosome 14. Genomic DNAs from 49 patients with chronic B-cell leukemia and the related lymphomas were examined by Southern blot hybridization using 2 separate probes, named p alpha 1.4P and p alpha .5B, from the BCL3 gene locus. None of the 18 patients with leukemic manifestations of non-Hodgkin's lymphomas had detectable BCL3 rearrangements. Of 31 patients with CLL, 2 had the BCL3 rearrangements. A comigration study using the C alpha and C epsilon constant gene probe from IGH indicated that the t(14;19) translocation occurred in these 2 patients, and they were diagnosed with CLL/prolymphocytic (PL) according to the French-American-British (FAB) classification. Probes for the IGH locus revealed that leukemia cells of the 2 patients each were clonal, indicating that both small lymphocytes and prolymphocytoid cells found in the peripheral blood of one patient had the t(14;19), as well as a major population of the small lymphocytes in the peripheral blood of a second patient. It thus appears that tumor cells carrying the t(14;19) constitute a distinct disease entity in a group of chronic B-cell leukemia, that has a converting potential to more aggressive forms.

Aged↗
PubMed1994

[Primary spinal intramedullary malignant lymphoma: case report].

We report a case of primary spinal intramedullary malignant lymphoma. A 48-year-old man suffered from numbness and weakness of the left leg for 8 months. He was admitted to the hospital with progressive paraplegia and sudden onset of urinary retention. MRI revealed a low intensity mass on T1-weighted image with diffuse enhancement by Gd-DTPA in the thoracic spinal cord. An intramedullary spinal cord tumor was suspected and an urgent laminectomy (C7-Th5) was performed for decompression and confirmation. In the operation, the spinal cord was seen to be diffusely swollen, but no apparent tumor was identified either in color or consistency, and only biopsy was performed. The pathological diagnosis was malignant lymphoma (diffuse medium size-cell type). Investigations excluded the presence of lymphoma in other sites in the central nervous system and in the extraneural organs. We diagnosed a primary spinal intramedullary malignant lymphoma. Postoperative irradiation and chemotherapy were performed. After the irradiation with 16Gy to the tumor and 30Gy to the whole spinal axis, the tumor disappeared on MRI. One month later MRI demonstrated two markedly enhanced lesions in the right frontal lobe white mantle and the corpus callosum. He died of progressive respiratory disturbance 15 months after the beginning of his illness. Primary involvement of the spinal cord in malignant lymphoma is rare. Only 12 cases have been reported. The number of cases of malignant lymphoma in the central nervous system has gradually increased and it must be taken into consideration when diagnosing spinal cord tumors. We are looking forward to developing curative means including chemotherapy and radiotherapy.

Combined Modality Therapy↗
PubMed1994

Clinical aspects of B-cell malignancy involving the BCL1/PRAD1 locus.

BCL1/PRAD1 is the gene locus involved in the t(11;14)(q13;q32) translocation, which often occurs in a proposed subtype of non-Hodgkin's lymphoma of B-cell phenotype (B-NHL), named mantle cell lymphoma (MCL). When 67 Japanese patients with B-NHL were examined using two separate probes composed of the BCL1 MTC probe and the PRADI cDNA probe, rearrangement of BCL1/PRAD1 or overexpression of PRAD1 was detected in 11 patients. Among 13 patients with MCL, 8 had the abnormalities (61%) and the MTC probe detected the BCL1 rearrangement in 5 (38%). Five of the 6 MCL patients studied (83%) showed PRAD1 overexpression. These frequencies were compatible with those reported for Western patients. Although the remaining three with BCL1/PRAD1 abnormalities were diagnosed as having other histologies, 11 patients had advanced diseases, with dissemination to the extranodal sites. Except for one with diffuse large cell lymphoma, they had a slowly progressive disease, and none of the patients displayed clinical or pathological transformation. The tumor cells usually expressed CD5 and lacked CD10. The cells were completely uniform in the expression of IgM and/or IgD, and in the absence of C mu gene deletion. It thus appears that B-malignancies involving the BCL1/PRAD1 locus constitute a refined disease entity.

Adult↗
PubMed1993

Developmental and functional impairment of T cells in mice lacking CD3 zeta chains.

CD3 zeta is a component of the T cell antigen receptor (TCR) complex and is important for signal transduction. We have established mice selectively lacking CD3 zeta but able to express CD3 eta, a polypeptide produced from the same locus through alternative splicing, using the method of gene targeting in embryonic stem cells. In homozygous mutant mice, the numbers of thymocytes and peripheral T cells were greatly reduced and the expression levels of TCR on these cells were 5-fold lower than those on wild-type cells. By contrast, TCR gamma delta+ intestinal intraepithelial lymphocytes were not obviously affected by the mutation. T cells from homozygous mutants exhibited an impaired proliferative response. These results imply that CD3 zeta has a critical role in the development and signal transduction of T cells in vivo.

Animals↗
PubMed1993

Heinz body hemolytic anemia induced by DQ-2511, a new anti-ulcer drug, in dogs.

DQ-2511, a new anti-ulcer drug, was administered to beagle dogs for 4 weeks to investigate the mechanism whereby this drug induced hemolytic anemia and its reversibility in comparison with beta-acetylphenylhydrazine. Hemolytic anemia accompanied by an increase in the number of cells containing Heinz bodies that was preceded by a marked decrease in blood-reduced glutathione concentration was observed in dogs receiving 600 mg/kg of DQ-2511, but only a slight increase in the methemoglobin level was noted. beta-Acetylphenylhydrazine, however, caused hemolytic anemia accompanied by marked increases in both Heinz body-containing cells and methemoglobin concentration, but the blood-reduced glutathione concentration was not decreased consistently with the formation of Heinz bodies. Hemolytic anemia disappeared after a 4-week recovery period in the dogs that received DQ-2511. These results suggest that decreases in reduced glutathione in erythrocytes play an important role in the anemia and Heinz body formation induced by DQ-2511, but not by beta-acetylphenylhydrazine.

Administration, Oral↗
PubMed1993

Effect of endurance training on angiogenic activity in skeletal muscles.

The effect of endurance training on angiogenic activity in skeletal muscle was investigated using cell culture. The exercised rats were trained on a rodent treadmill, 5 days a week for 9 weeks. After the training program, a significant increase (7.8%) in mass was found in soleus muscle (MS), although we noted no apparent increase in gastrocnemius muscle and extensor digitorum longus muscle. The extracts from all the muscles (especially from the MS) of trained rats considerably increased the capillary growth in an in vitro angiogenesis model, in which microvascular fragments and myofibroblastic (Mf) cells isolated from lipid tissues were grown in co-culture. In addition, the extract from the MS of trained rats increased the DNA synthesis and growth of bovine capillary endothelial (BCE) cells, although the extract did not stimulate the growth of Mf cells. Moreover, the extract from the MS of trained rats notably enhanced the activity of plasminogen activator in the conditioned medium of BCE cells compared with that of sedentary rats. On the other hand, extracts from the MS of both sedentary and trained rats increased the synthesis of collagen by Mf cells and metalloproteinase activity in the conditioned medium of BCE cells to the same degree. These results suggest that endurance training increases the angiogenic activity in skeletal muscles.

Animals↗
PubMed1993

Hepatocellular carcinoma: the diagnostic difficulties of ultrasonography and analysis of risk factors in MHTS.

Thirty-nine cases of hepatocellular carcinoma (HCC) out of 55,135 examinees were examined. The diagnostic problems of ultrasonography (US) in detecting HCC and the risk value of 10 factors in HCC were discussed. We also propose the surveillance programs for HCC in Multiphasic Health Testing and Services (MHTS). US will be performed at 3-, or 6 monthly intervals in conjunction with AFP monitoring for the examinees over 50 males and over seventy females with liver dysfunction (GOT > 38 IU/ml) is recommended.

Adult↗
PubMed1993

Effect of running training on uncoupling protein mRNA expression in rat brown adipose tissue.

The effect was investigated of endurance training on the expression of uncoupling protein (UCP) mRNA in brown adipose tissue (BAT) of rats. The exercised rats were trained on a rodent treadmill for 5 days per week and a total of 9 weeks. After the training programme, a marked decrease in BAT mass was found in terms of weight or weight per unit body weight; there was a corresponding decrease in DNA content and a downward trend in RNA and glycogen levels. The UCP mRNA was present at a markedly decreased level in BAT of trained animals. In consideration of the reduced levels of mRNAs for hormone-sensitive lipase and acyl-CoA synthetase, the brown adipose tissue investigated appeared to be in a relatively atrophied and thermogenically quiescent state.

Adipose Tissue, Brown↗
PubMed1993

Conditions required for myelopoiesis in murine spleen.

While the spleen is an active site for myelopoiesis during the late embryonal and perinatal stages, the activity is gradually lost later. However, myelopoiesis in the adult spleen can be reactivated by irradiation or various stimulants. In this study we investigated factors which determine the myelopoiesis-supporting activity in the adult spleen. To address this question, we used scid mouse because virtually no lymphocytes, which might compete in the splenic microenvironment with hematopoietic progenitors, are present there. The results demonstrated: 1. Even in scid mouse, the myelopoiesis-supporting activity in the spleen is lost within a week after birth as in normal mice. 2. While myelopoiesis does not occur in the spleen of unstimulated scid mouse by bone marrow transfer alone, myelopoiesis in the spleen is reactivated by irradiation or lipopolysaccharide (LPS) application. 3. Myelopoiesis in the spleen induced by irradiation is dependent on c-kit and its ligand steel factor (SLF), because it was suppressed completely by the monoclonal antibody (mAb) against c-kit. 4. The expression of SLF transcripts in the spleen was enhanced after irradiation. These results suggest that the factor which determines myelopoietic activity in the spleen resides primarily in the status of the splenic microenvironment.

Animals↗
PubMed1993

Superoxide dismutase with prolonged in vivo half-life inhibits intravascular hemolysis and renal injury in burned rats.

Although superoxide radicals and related metabolites have been postulated to underlie the pathogenesis of burn injury, critical evidence supporting this hypothesis is lacking. To test whether superoxide radicals play critical roles in burn injury, the effect of a superoxide dismutase (SOD) derivative (SM-SOD) was tested on intravascular hemolysis and renal tubular injury in rats subjected to burn shock. Within 3 hours after a given full-thickness burn of approximately 24% of body surface area, plasma levels of lipid peroxides increased significantly with concomitant increase in intravascular hemolysis. Histological examination showed a marked deposition of hemoglobin-like casts in renal tubules of the burned rats. Intravenous administration of SM-SOD (10 mg/kg) 30 minutes before the burn injury significantly inhibited the increase of plasma lipid peroxides and the occurrence of intravascular hemolysis. SM-SOD also inhibited the deposition of casts in renal tubules. These results indicate that superoxide radicals play critical roles in the pathogenesis of intravascular hemolysis and renal damage induced by burn injury.

Animals↗
PubMed1993

TCR isoform containing the Fc receptor gamma chain exhibits structural and functional differences from isoform containing CD3 zeta.

The structure and function of the TCR-CD3 complex containing a homodimer of the gamma chain of the high affinity receptor for IgE (FcR gamma) (FcR gamma+ TCR) was investigated by transfecting the FcR gamma gene into a CD3 zeta-, CD3 eta-, FcR gamma- T cell line. Introduction of FcR gamma, as well as CD3 zeta, induced a high expression of the TCR-CD3 complex on the cell surface. Transfected FcR gamma formed a homodimer and associated firmly with the TCR alpha beta dimer but only weakly with the CD3 gamma delta epsilon. Stimulation of both FcR gamma and CD3 zeta transfectants by antibodies against TCR or CD3 induced accumulation of inositol phosphates, the Ca2+ response, IL-2 production, and growth inhibition. On the other hand, antigen stimulation of transfectants expressing FcR gamma as well as CD3 zeta induced IL-2 production, but only the latter exhibited the antigen-induced growth inhibition. In vitro kinase assay suggested that the CD3 zeta dimer but not the FcR gamma dimer associates with the Fyn kinase. These results indicate that the FcR gamma homodimer is able to form a functional TCR complex but that the mode of assembly and the signaling function of FcR gamma+ TCR, including its association with tyrosine kinase(s), may differ from the TCR-CD3 complex containing CD3 zeta homodimers (zeta+ TCR). This provides an example which illustrates that different TCR isoforms mediate distinct signals and functions.

Animals↗