Biomedical subjects

H Ohno

Publications and source records attributed to H Ohno.

At least 181 records · Page 10Linked to original sources

PubMed1998

Corrosion of three experimental AgMn-based casting alloys.

OBJECTIVE: Alloys based on AgMn are being evaluated in our laboratory for their possible use as an alternative to Type III dental alloys. They respond to heat treatment and develop hardness values comparable to that of Type III alloys. The objective of the present research was to evaluate their corrosion characteristics. METHODS: The three experimental silver-based alloys of the following composition (at%): (1) 63Ag37Mn, (2) 60Ag35Mn5Au and (3) 60Ag35Mn5Pd, were tested in their peak-hardened condition. Following 0.5 h open-circuit potential (OCP) measurement of each alloy in a phosphated buffer saline (PBS) solution, its current-potential profile was generated by the cyclic voltammetry technique within -1300 and +200 mV (SCE) at 1 mV s-1. In a separate test, the OCP of each alloy was monitored over a 24 h period. RESULTS: Each of the three alloys showed ennoblement of their OCP over time due to dissolution of Mn and consequent enrichment with Ag (Au or Pd). At 24 h, the two ternary alloys were the most noble followed by the binary alloy. With respect to the cyclic voltammetry, oxidation of Ag was noted during forward scans at around 0 mV. The reverse scan was associated with a reduction current peak between -37 and -128 mV. The values for this peak, which is a measure of Ag oxidation, were highest (11.5 mA cm-2) for the binary alloy followed by the Au- (2.9 mA cm-2) and Pd-containing (0.04 mA cm-2) alloys, respectively. This indicates that, for equivalent concentration, Pd is more effective in reducing Ag corrosion than Au. SIGNIFICANCE: Alloys based on the AgMn system are as hard as Type III dental alloys. Information on the corrosion characteristics of the AgMn-based alloys presented here is of value in further development of this alloy system.

Corrosion↗

PubMed1998

Detection of t(8;14)(q24;q32) by polymerase chain reaction for long DNA targets: a report of two patients with B-cell non-Hodgkin's lymphoma.

We developed a novel technique for long-distance polymerase chain reaction (LD-PCR) to detect t(8;14)(q24;q32). LD-PCR can amplify up to 12 kb of DNA encompassing the c-MYC and constant regions of the immunoglobulin heavy chain gene. In this report, we present two patients with B-cell non-Hodgkin's lymphoma. Clinical materials obtained from these patients were examined by LD-PCR. One patient had small noncleaved cell lymphoma (case 1) and the other had diffuse large cell lymphoma (case 2). Both patients showed central nervous system involvement. LD-PCR using appropriate primer pairs and a newly available Taq polymerase for longer product synthesis detected a 9.6 kb (case 1) and a 2.4 kb (case 2) c-MYC/C gamma fusion product indicative of t(8;14) in all materials in which lymphoma cells were shown positive by microscopic examination. LD-PCR provides an advantage in rapid detection of lymphoma cells carrying t(8;14).

Adolescent↗

PubMed1998

A case of primary splenic large cell lymphoma with a t(9;14)(p13;q32).

t(9;14)(p13;q32), a subtype of 14q32 translocation, plays an essential role in the development of lymphoplasmacytoid lymphoma. t(9;14)(p13;q32) Causes juxtaposition of the PAX-5 gene on 9p13 and the IgH gene on 14q32, leading to the deregulation of the PAX-5 gene. We report a case of primary splenic lymphoma with a t(9;14). The histological diagnosis was diffuse large B-cell lymphoma without plasmacytoid differentiation. The lymphoma cells showed a complex karyotype including a t(9;14). Southern blot analysis localized the breakpoint of the PAX-5 gene within a couple of kb regions upstream of the exon 1A, although the involvement of the PAX-5 gene with the immunoglobulin heavy chain gene could not be confirmed.

Chromosomes, Human, Pair 14↗

PubMed1998

Expression of the PAX5/BSAP transcription factor in haematological tumour cells and further molecular characterization of the t(9;14)(p13;q32) translocation in B-cell non-Hodgkin's lymphoma.

The PAX5 gene encodes the BSAP (B-cell-specific activator protein) which is a key regulator of B-cell development and differentiation. A recurring translocation t(9;14)(p13;q32) in non-Hodgkin's lymphoma moves the PAX5 on 9p13 within close proximity of the immunoglobulin heavy chain gene (IGH). KIS-1 cell line was established from a patient with diffuse large cell lymphoma of B-cell type carrying t(9;14). We analysed PAX5/BSAP expression by Northern and Western blotting in a panel of haematological tumour cell lines with other chromosome abnormalities in comparison with that of KIS-1. PAX5 mRNA and BSAP expression were detected in all B-cell lines tested, and the high level in KIS-1 was confirmed. However, a diffuse large B-cell lymphoma cell line and an acute B-lymphoid/myeloid leukaemia cell line expressed the PAX5/BSAP at levels comparable with KIS-1. PAX5 transcripts were readily detectable in clinical materials with a wide variety of B-cell neoplasms by reverse transcriptase-mediated polymerase chain reaction (PCR). Thus, PAX5/BSAP activation in haematological tumour cells is not necessarily associated with t(9;14). Although binding sites for BSAP have been identified in the promoters of CD19, this study failed to find clear correlation between the level of PAX5/BSAP expression and that of CD19. In contrast to KIS-1 in which the E mu enhancer of IGH was juxtaposed to PAX5, cloning of t(9; 14) from another case by long-distance PCR revealed that the PAX5 promoter was linked to a Cgamma constant region in divergent orientation, suggesting that the mechanism of PAX5 activation through recombination with IGH varies among individual cases. Breakpoints on 9p13 of the two translocations were clustered upstream of PAX5, leaving the PAX5 coding region intact.

Base Sequence↗

PubMed1998

An increase in basal glucocorticoid concentration with age induces suppressor macrophages with high-density Fc gamma RII/III.

Ageing is usually accompanied by a decline in immune and neuroendocrine functions. To elucidate the mechanisms underlying age-related immunosuppression, the functions and surface phenotypes of peritoneal cells in the monocyte/macrophage lineage from old mice were investigated. The role of glucocorticoids (GC) in the immunomodulation was also examined. Proliferative responses of spleen cells from control mice stimulated with concanavalin A (Con A) were significantly suppressed by adding peritoneal exudate cells from old mice. Flow cytometry analysis revealed that the proportion of MAC-1+ cells with a high density of type II or type III receptor for the Fc portion of IgG (Fc gamma RII/IIIbright cells) was increased markedly in the periotoneal exudate cells from old mice. The prominent suppressor activity for Con A responses of control spleen cells was found in the Fc gamma RII/IIIbright cells, whereas MAC-1+ cells with a low density of Fc gamma RII/III (Fc gamma RII/IIIdull cells) did not suppress the Con A responses. On the other hand, both the basal corticosterone concentrations in serum and the mRNA expression for GC receptor in peritoneal exudate cells increased significantly in old mice. Furthermore, the proportion of Fc gamma RII/IIIbright cells in peritoneal exudate cells from old mice was normalized on administration of the GC antagonist RU 38,486 (mifepristone). These results suggest that the increase in basal corticosterone concentrations in old mice induces the generation of Fc gamma RII/IIIbright suppressor cells, possibly leading to the immune-suppressive state.

Aging↗

PubMed1998

Relationship between antimycobacterial activities of rifampicin, rifabutin and KRM-1648 and rpoB mutations of Mycobacterium tuberculosis.

We compared the in-vitro antimycobacterial activities of rifabutin and KRM-1648, two rifamycin derivatives, with that of rifampicin against 163 strains of Mycobacterium tuberculosis. We also evaluated the correlation between the level of resistance to rifampicin, rifabutin and KRM-1648 and genetic alterations in the rpoB gene. All 82 strains susceptible to rifampicin or resistant to rifampicin with MICs < or = 16 mg/L were susceptible to rifabutin and KRM-1648 with MICs < or = 1 mg/L. Seventy-six of 81 strains resistant to rifampicin with MICs > or = 32 mg/L were resistant to both rifabutin and KRM-1648, but with lower MICs than those of rifampicin. KRM-1648 showed more potent antimycobacterial activity than rifabutin against organisms with low MICs (< or = 1 mg/L), while rifabutin was more active than KRM-1648 against organisms with high MICs (> or = 2 mg/L). A total of 96 genetic alterations around the 69 bp core region of the rpoB gene were detected in 92 strains. Alterations at codons 515, 521 and 533 in the rpoB gene did not influence the susceptibility to rifampicin, rifabutin and KRM-1648. Point mutations at codons 516 and 529, deletion at codon 518 and insertion at codon 514 influenced the susceptibility to rifampicin but not that to rifabutin or KRM-1648. With the exception of one strain, all alterations at codon 513 and 531 correlated with resistance to the three test drugs. The resistant phenotype of strains with an alteration at codon 526 depended on the type of amino acid substitution. Our results suggest that analysis of genetic alterations in the rpoB gene might be useful not only for predicting rifampicin susceptibility, but also for deciding when to use rifabutin for treating tuberculosis. Further studies may be required to determine the usefulness of KRM-1648.

Amino Acid Sequence↗

PubMed1998

Two cases of unilateral axillary Paget's disease.

We herein report two cases of unilateral axillary Paget's disease. Extramammary Paget's disease commonly occurs in the anogenital area. Unilateral axillary occurrence is relatively rare. One defect was reconstructed with a pedicled scapular flap, and the other was reconstructed with split-skin graft after excision of the tumor. No recurrence was seen in either patient three years postoperatively. However, although the patient who had been reconstructed with a pedicled flap recovered uneventfully, the other patient, who had been reconstructed with a split-skin graft, suffered from axillary contracture due to the shrinkage of the grafted skin after surgery. A skin graft requires fixation for a long period to prevent shrinkage, which causes axillary contracture. Therefore, from the viewpoint of quality of life, reconstruction using flaps is recommended for axillary lesions.

Aged↗

PubMed1998

Erythropoietin-producing renal cell carcinoma arising from acquired cystic disease of the kidney.

A 49-year-old woman had been on hemodialysis for 18 years. She presented with left back pain and macrohematuria. Radiologic studies demonstrated a left renal tumor with acquired cystic disease of the kidney. Her serum erythropoietin (EPO) level was 78.4 U/L despite no history of EPO supplementation. Left radical nephrectomy was performed. Pathologic examination revealed EPO-producing renal cell carcinoma. After surgery, the patient's serum EPO level decreased markedly to 15.1 U/L. The measurement of serum EPO levels may be useful for detecting and monitoring a recurrence of renal cell carcinoma with acquired cystic disease of the kidney in patients on long-term hemodialysis.

Carcinoma, Renal Cell↗

PubMed1998

Endurance training alters antioxidant enzyme gene expression in rat skeletal muscle.

The effects of endurance training on gene expression of superoxide dismutase (SOD) and glutathione peroxidase (GPX) were investigated in type 2a and 2b skeletal muscles, as well as heart and liver, in the rat. Female Sprague-Dawley rats (4 months old, 300-320 g) were randomly divided into a trained (T, n = 11) and a control (C, n = 10) group and were pair fed a diet consisting of 66% cornstarch and 34% basal diet that contained all essential nutrients. Training was conducted on a treadmill at 25 m x min(-1), 10% grade for 2 h per day, 5 days per week for 10 weeks, resulting in a 79% (p < 0.01) increase in citrate synthase activity in the deep portion of vastus lateralis muscle (DVL, type 2a). Cu-Zn SOD activity was 35% higher (p < 0.01) in DVL of T versus C rats, and Cu-Zn SOD mRNA abundance showed a 125% increase with training (p < 0.05). Cu-Zn SOD protein content was not altered in DVL, but increased significantly (p < 0.05) in the superficial portion of vastus lateralis (type 2b) with training. Trained rats showed a 66% higher (p < 0.05) Mn SOD protein content in DVL, but Mn SOD activity and mRNA abundance were not affected. Training also significantly increased GPX activity by 62% (p < 0.05), without changing its mRNA abundance, in the DVL. Heart and liver showed a 112 and 58% increase (p < 0.01) in Cu-Zn SOD mRNA abundance with training, respectively, but no other training adaptation was detected. These data indicate that endurance training can promote gene expression of muscle antioxidant enzymes in a fiber-specific manner. Training appears to upregulate Cu-Zn SOD mRNA abundance in a number of aerobic tissues, whereas Mn SOD and GPX induction observed in DVL may occur at the post-transcriptional levels.

Animals↗

PubMed1998

Tissue distribution of immunoreactive mouse extracellular superoxide dismutase.

Protein content and mRNA expression of extracellular superoxide dismutase (EC-SOD) were investigated in 16 mouse tissues. We developed a double-antibody sandwich ELISA using the affinity-purified IgG against native mouse EC-SOD. EC-SOD could be detected in all of the tissues examined (lung, kidney, testis, brown fat, liver, adrenal gland, pancreas, colon, white fat, thymus, stomach, spleen, heart, skeletal muscle, ileum, and brain, in decreasing order of content measured as microg/g wet tissue). Lung showed a markedly higher value of EC-SOD than other tissues. Interestingly, white fat had a high content of EC-SOD in terms of micrograms per milligram protein, which corresponded to that of lung. Kidney showed the strongest expression of EC-SOD mRNA. Relatively strong expression of the mRNA was observed in lung, white fat, adrenal gland, brown fat, and testis. Heart and brain showed only weak signals, and no such expression could be detected in either digestive organs or skeletal muscle. Immunohistochemically, EC-SOD was localized mainly to connective tissues and vascular walls in the tissues examined. Deep staining in the cytosol was observed in the cortical tubular cells of kidney. These results suggest that EC-SOD is distributed systemically in mice and that the physiological importance of this enzyme may be a compensatory adaptation to oxidative stress, particularly in lung and kidney.

Adipocytes↗

PubMed1998

Effects of SS320A, a new cysteine derivative, on the change in the number of goblet cells induced by isoproterenol in rat tracheal epithelium.

We examined the effects of SS320A ((-)-(R)-2-amino-3-(3-hydroxypropylthio)propionic acid), a new cysteine derivative, on the change in the number of goblet cells induced by isoproterenol in rat tracheal epithelium. Four types of goblet cells were characterized in tracheal epithelium according to their size and staining affinity with Alcian blue (AB) / periodic acid Schiff (PAS). When each rat was given a single daily injection of isoproterenol (0.05 mg/kg, i.p.) for 14 days, a significant increase was observed in AB/PAS-positive cells that were recognizable as goblet cells in tracheal epithelium. When SS320A (10-100 mg/kg, p.o.) or propranolol (1 mg/kg, s.c.) was administered before each injection of isoproterenol, the increase in the number of goblet cells induced by isoproterenol was significantly inhibited. There was no difference between male and female rats with regard to this inhibitory action. On the other hand, ambroxol, bromhexine, L-cysteine ethyl ester and S-carboxymethylcysteine (100 mg/kg, p.o., respectively), which are used as expectorants, had no inhibitory effects on the isoproterenol-induced change in the number of goblet cells. Four metabolites (M1-M4) of SS320A in rats also failed to inhibit the change induced by isoproterenol. These data suggest that SS320A itself may have a beneficial effect against mucus hypersecretion in chronic respiratory diseases.

Animals↗

PubMed1998

Detection of Mycobacterium tuberculosis in preserved tuberculous lymph nodes by polymerase chain reaction.

We evaluated the usefulness of three types of polymerase chain reaction (PCR) targeting 16S rRNA, protein antigen b and IS6110 in detecting Mycobacterium tuberculosis in preserved tuberculous lymph nodes. The detection limit of all PCR methods was 100 colony forming unit (CFU) of M. tuberculosis in tissue. The test samples included eight paraffin-embedded tuberculous lymph nodes containing microscopical epithelioid cell granuloma with caseous necrosis and Langhans giant cells. Although acid-fast stained organisms in lymph node tissue were not detected in any sample, all three types of PCR tests were positive in four of eight lymph nodes. Our results suggest that PCR is not only a rapid and sensitive diagnostic method for tuberculous lymphadenitis, but also clinically significant in retrospective study for detecting M. tuberculosis even in some preserved lymph node tissues without evidence of acid-fast stained organisms.

Antigens, Bacterial↗

PubMed1998

Thirteen-week repeated oral dose toxicity study of ecabapide, a gastroprokinetic drug, in dogs and rats.

Thirteen-week oral repeated dose toxicity of ecabapide, a gastroprokinetic drug, was investigated in dogs at dosage levels of 50, 175 or 600 mg/kg, and in rats at dosage levels of 25, 100, 400 or 1600 mg/kg. In dogs, vomiting, aqueous salivation, body weight gain inhibition, and hemolytic anemia, together with an increase in Heinz body formation, were observed at 175 and/or 600 mg/kg. Histological examination revealed enhanced hemosiderin deposition in the liver and spleen, retention of erythrocytes in the splenic sinus and enhanced erythropoiesis in bone marrow at 175 and/or 600 mg/kg. In the rat study, although increases in serum total protein, albumin and calcium, as well as increased liver and kidney weights, were observed at 400 and/or 1600 mg/kg, no obvious morphological changes were seen. The hemolytic anemia and an increased Heinz body formation were not observed in rats, indicating a species difference. On the basis of these results, the non-toxic dose of ecabapide was considered to be 50 mg/kg in dogs and 100 mg/kg in rats.

Administration, Oral↗

PubMed1998

Non-Hodgkin's lymphoma involving bilateral breasts.

We describe here two cases of diffuse large cell type non-Hodgkin's lymphoma affecting the bilateral breasts. The contralateral tumor in one case appeared 17 months after the first mastectomy, whereas the bilateral tumors occurred concurrently in the other patient who was pregnant and showed widespread dissemination at initial presentation. Lymphoma cells from both cases showed the mature B-cell immunophenotype and had rearrangements of the BCL6 gene. Both patients developed progressive disease despite chemo-radiotherapy and died of leukemic manifestations. There were no apparent pathological features of lymphomas of mucosa-associated lymphoid tissue origin.

Adult↗

PubMed1998

Polymerase chain reaction amplification of long DNA targets: application to analysis of chromosomal translocations in human B-cell tumors (review).

Chromosomal translocations in human leukemias generate fusion transcripts containing messages from two genes involved in the translocation, and these have been the targets for reverse transcriptase-mediated polymerase chain reaction (PCR). In contrast, many of the translocations in B-cell tumors involve immunoglobulin gene (IG) loci, and coding regions of the oncogenes on partner chromosomes are not interrupted by the translocation. Therefore, targets for PCR amplification are single-copy oncogene/IG fusion sequences within the complex genomic DNA. We present here a novel strategy for detection of translocations in B-cell tumors on the basis of long-distance (LD-) PCR that is capable of amplifying up to 30 kb of DNA. LD-PCR is a general method using primer pairs designed for distinctive regions of IG and oncogenes involved in translocations, and amplifying long DNA fragments encompassing the oncogene/IG junction. LD-PCR is capable of detecting virtually all the important translocations in B-cell tumors, including t(8;14)(q24;q32), t(14;18)(q32;q21), t(3;14)(q27;q32) and its variants. We show here that LD-PCR can substitute for time-consuming Southern blot hybridization in the rapid detection of these translocations. Furthermore, as amplified fragments obtained by LD-PCR contained exons and flanking sequences of the oncogenes and IGs, restriction analysis and nucleotide sequencing of the products refined the characteristics of translocations.

Chromosome Mapping↗

PubMed1998

Adhesion of adhesive resin to dental precious metal alloys. Part I. New precious metal alloys with base metals for resin bonding.

New dental precious metal alloys for resin bonding without alloy surface modification were developed by adding base metals (In, Zn, or Sn). Before this, binary alloys of Au, Ag, Cu, or Pd containing In, Zn, or Sn were studied for water durability and bonding strength with 4-META resin. The adhesion ability of the binary alloys was improved by adding In equivalent to 15% of Au content, Zn equivalent to 20% of Ag content, and In, Zn, or Sn equivalent to 5% of Cu content. There was no addition effect of the base metals on Pd, however 15% of In addition improved adhesion with Pd-based alloys containing equi-atomic % of Cu and Pd. The alloy surfaces were analyzed by XPS and showed that oxides such as In2O3, ZnO, or SnO play an important role in improving the adhesive ability of the alloys.

Acrylic Resins↗

PubMed1998

Adhesion of adhesive resin to dental precious metal alloys. Part II. The relationship between surface structure of Au-In alloys and adhesive ability with 4-META resin.

Adhesion of 4-META to Au-In alloy was improved by adding In equivalent to .15% of Au content. On the basis of the results of Au-In alloys analyzed by XPS, the present study investigated the reason why adhesion of the Au-In alloy was improved. The O 1s spectrum could be separated into three oxygen chemical states, In2O3, chemisorbed H2O, and physisorbed H2O. The amount of chemisorbed H2O decreased remarkably with increasing amount of In. It is considered that the poor adhesive ability of the pure gold and alloys containing only small amounts of In was due to the chemisorbed H2O molecules and insufficient indium oxide on the alloy surface. It was established that excellent adhesion requires an oxide with chemical affinity for 4-META to cover at least 50% of the alloy surface.

Acrylic Resins↗

PubMed1998

Effect of Cr and Cu addition on corrosion behavior of Ni-Ti alloys.

The corrosion behavior of three Ni-Ti alloys with compositions as commercial super-elastic orthodontic wires was investigated using polished plate specimens. Corrosion resistance was estimated by potentiodynamic polarization measurement in 0.9% NaCl and 1% lactic acid solutions and analysis of released metals by atomic absorption spectrophotometry. The influence of Cr and Cu addition on the structure of the surface oxide film was examined by X-ray photoelectron spectroscopy (XPS). Addition of 0.19 at% Cr had little effect on the structure of the oxide films and the corrosion resistance of the Ni-Ti alloys. For Ni-Ti-5Cu-0.3Cr alloy, the metallic Cu was enriched at the alloy/oxide film interface, resulting in increased susceptibility to pitting corrosion above +1000 mV. However, the passive current density and the amount of released Ni were not significantly increased by the addition of Cu. The study showed that small amounts of Cr and Cu added to change the super-elastic characteristics do not change the corrosion resistance of the Ni-Ti alloy freely immersed in simulated physiological environments.

Chromium↗