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H Ohno

Publications and source records attributed to H Ohno.

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

MT neurons in the macaque exhibited two types of bimodal direction tuning as predicted by a model for visual motion detection.

We previously proposed a model for detecting local image velocity on the magnocellular visual pathway (Kawakami & Okamoto (1996) Vision Research, 36, 117-147). The model detects visual motion in two stages using the hierarchical network that includes component and pattern cells in area MT. To validate the model, we predicted two types of bimodal direction tuning for MT neurons. The first type is characteristic of component cells. The tuning is bimodal when stimulated with high-speed spots, but unimodal for low-speed spots or for bars. The interval between the two peaks widens as the spot's speed increases. The second type is characteristic of pattern cells. The tuning is bimodal when stimulated with low-speed bars, but unimodal for high-speed bars or for spots. The interval widens as the bar's speed decreases. To confirm this prediction, we studied the change of direction tuning curves for moving spots and bars in area MT of macaque monkeys. Out of 35 neurons measured at various speeds, six component cells and four pattern cells revealed the predicted bimodal tunings. This result provided neurophysiological support for the validity of the model. We believe ours is the first systematic study that records the two types of bimodality in MT neurons.

Animals↗
PubMed1999

Investigation of albumin-synthesizing ability in rat cirrhotic liver-derived hepatocytes using primary hepatocyte culture.

BACKGROUND/AIMS: In cirrhosis, despite a decrease in the total number of hepatocytes, a normal serum albumin level is maintained during the compensatory stage of the disease in many cases. Therefore, to elucidate the mechanism in hepatocytes related to the regulation of the serum albumin level, the albumin-synthesizing ability of individual hepatocytes was investigated in cirrhotic rats. METHODS: Cirrhotic rats were prepared by oral administration of furfural to male Wistar rats for 20 weeks. Albumin-synthesizing abilities of liver and of isolated hepatocyte culture were evaluated by measuring the albumin concentration in blood and culture supernatant. Expressions of albumin mRNA were compared using Northern blotting. Furthermore, transcriptional activity of the albumin gene was measured using the promoter domain of the gene. RESULTS: The total number of hepatocytes in rat cirrhotic liver was significantly decreased compared to that in normal rat liver. However, there were no significant differences in levels of serum albumin or albumin mRNA expression between cirrhotic and normal liver. In primary hepatocyte culture, albumin mRNA expression, the amount of albumin secretion and the albumin promoter activity were clearly enhanced in cirrhotic hepatocytes compared to normal hepatocytes. CONCLUSION: Although the total number of hepatocytes was decreased in the rat cirrhosis models used in this study, the serum albumin level was maintained and albumin-synthesizing ability was enhanced at the transcriptional level in the individual hepatocytes. These results suggest that the maintenance of serum albumin levels in compensated cirrhosis may be due to enhanced albumin synthesis by the hepatocytes.

Animals↗
PubMed1999

The effect of exercise training on oxidative damage of lipids, proteins, and DNA in rat skeletal muscle: evidence for beneficial outcomes.

Moderate daily exercise is known to be beneficial to health, reducing risks of a number of age-related disorders. Molecular mechanisms that bring about these effects are not clear. In contrast, it has been claimed that some types of prolonged physical exertion are detrimental to health because active oxygen species are generated excessively by enhanced oxygen consumption. Using two age groups of rats, young (4 week) and middle aged (14 months), we investigated the effects of long-term swimming training on the oxidative status of phospholipids, proteins, and DNA. The concentration of thiobarbituric acid reactive substances and 4-hydroxynonenal protein adducts did not differ in the gastrocnemius muscle between exercised and nonexercised animals in the two age groups. The extent of carbonylation in a protein of molecular weight around 29 KDa and the amount of 8-hydroxydeoxyguanosine in nuclear DNA were smaller (p<.05) in the exercised rats than in the sedentary animals. Activities of DT-diaphorase (C1: 29.3+/-1.9; C2: 36.1+/-2.6; E1: 27.2+/-1.3; C2: 33.4+/-2.9 nmol/mg protein) and proteasome, a major proteolytic enzyme for oxidatively modified proteins were significantly higher in the exercised animals of both age groups (p<.05). The adaptive response against oxidative stress induced by moderate endurance exercise constitutes a beneficial effect of exercise.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed1999

K-ras codon 12 and p53 mutations in biopsy specimens and bile from biliary tract cancers.

To evaluate whether it is useful for diagnosis to detect K-ras and p53 mutations in biopsy specimens and bile of biliary tract lesions, 12 cholangiocarcinomas (CC), eight cases of cholangitis, seven gallbladder carcinomas (GBC), seven gallbladder cholesterol polyps, four cases of adenomyomatosis of the gallbladder and five cases of cholecystitis were examined. K-ras and p53 mutations in bile were detected by a two-step polymerase chain reaction (PCR) and nested PCR-single-strand conformation polymorphism (SSCP) analysis. In addition, p53 protein expression in biopsy specimens from CC were examined by immunostaining. K-ras mutations at codon 12 were detected in 50% of CC and 57.1% of GBC in both biopsy specimens and bile. The incidence of p53 mutations was 33.3% in CC and 42.9% in GBC. p53 protein overexpression was observed in 60% CC biopsy specimens. In contrast, K-ras and p53 abnormalities were not detected in any non-neoplastic biliary tract lesion. K-ras and p53 mutations in biliary tract cancers showed the same mutation patterns in spite of differences in the collection methods used between bile and biopsy specimens or surgically resected tissue. Genetic analysis of K-ras and p53 mutations in biopsy specimens and bile may be useful for the diagnosis of biliary tract cancers, although it may be effectively limited to patients with advanced disease.

Base Sequence↗
PubMed1999

Upregulation of type I interferon receptor by IFN-gamma.

Type I interferon (IFN) receptor has a multichain structure composed of at least two distinct subunits, IFNAR-1 and IFNAR-2. In the present study, we demonstrated that IFN-gamma induced the expression of mRNA for IFNAR-1 and IFNAR-2 in a human hepatoma cell line, HepG2 cells. The induction was dose and time dependent. Because of this result, we examined the effect of combined treatment with type I IFN and IFN-gamma. The intracellular 2-5A-synthetase activity induced by combined treatment was significantly higher than that by type I IFN alone. This study suggests that combined treatment with type I IFN and IFN-gamma may be more effective than that of type I IFN alone and that the upregulation of type I IFN receptor may be one of the reasons. Our findings may have some relevance to the clinical use of IFN.

2',5'-Oligoadenylate Synthetase↗
PubMed1999

Relationship between genetic alteration of the rpsL gene and streptomycin susceptibility of Mycobacterium tuberculosis in Japan.

We have investigated the effect of genetic alterations in the rpsL gene on the MICs of streptomycin for Mycobacterium tuberculosis strains. Direct DNA sequencing showed a point mutation in 23/121 strains; in 18 strains the mutation was associated with an amino acid change. The MICs of streptomycin in 22 out of 23 point-mutated strains were > or = 256 mg/L. Restriction fragment length polymorphism (RFLP) analysis showed mutations at codon 43 in all 18 strains with point mutations in the same codon. Our results suggest that both RFLP and base sequencing analysis of the rpsL gene are useful for the rapid prediction of highly streptomycin-resistant strains of M. tuberculosis.

Deoxyribonucleases, Type II Site-Specific↗
PubMed1999

Fenestrated oculomotor nerve caused by meningioma around the cavernous sinus: a surgical pitfall in tumor removal: case report.

OBJECTIVE AND IMPORTANCE: The preservation of oculomotor nerves is one of the most significant issues regarding the resection of meningiomas around the cavernous sinus. CLINICAL PRESENTATION: We report the case of a patient whose oculomotor nerve was fenestrated, caused by a large meningioma around the cavernous sinus. The nerve function remained intact until surgery. INTERVENTION: During surgery, one trunk of the fenestrated nerve behind the tumor was sacrificed. The fenestrated shape of the nerve led us to the misjudgment that the preserved other trunk located along the upper margin of the tumor was the whole nerve. CONCLUSION: Although fenestrated oculomotor nerves may be rare, their possibility should be kept in mind during surgery around the cavernous sinus.

Aged↗
PubMed1999

Superoxide dismutase gene expression in skeletal muscle: fiber-specific adaptation to endurance training.

The effects of endurance training on the enzyme activity, protein content, and mRNA abundance of Mn and CuZn superoxide dismutase (SOD) were studied in various phenotypes of rat skeletal muscle. Female Sprague-Dawley rats were randomly divided into trained (T, n = 8) and untrained (U, n = 8) groups. Training, consisting of treadmill running at 27 m/min and 12% grade for 2 h/day, 5 days/wk for 10 wk, significantly increased citrate synthase activity (P < 0. 01) in the type I (soleus), type IIa (deep vastus lateralis, DVL), and mixed type II (plantaris) muscles but not in type IIb (superficial vastus lateralis, SVL) muscle. Mitochondrial (Mn) SOD activity was elevated by 80% (P < 0.05) with training in DVL. SVL and plantaris muscle in T rats showed 54 and 42% higher pooled immunoreactive Mn SOD protein content, respectively, than those in U rats. However, no change in Mn SOD mRNA level was found in any of the muscles. CuZn SOD activity, protein content, and mRNA level in general were not affected by training, except for a 160% increase in pooled CuZn SOD protein in SVL. Training also significantly increased glutathione peroxidase and catalase activities (P < 0.05), but only in DVL muscle. These data indicate that training adaptations of Mn SOD and other antioxidant enzymes occur primarily in type IIa fibers, probably as a result of enhanced free radical generation and modest antioxidant capacity. Differential training responses of mRNA, enzyme protein, and activity suggest that separate cellular signals may control pre- and posttranslational regulation of SOD.

Adaptation, Biological↗
PubMed1999

Genomic structure and chromosome mapping of the genes encoding clathrin-associated adaptor medium chains mu1A (Ap1m1) and mu1B (Ap1m2).

The protein mu1B is a member of the medium chain family of the clathrin-associated adaptor complex and is expressed exclusively in epithelial cells. We determined the genomic structure of previously cloned murine genes for mu1B (Ap1m2) and its closely related homolog, mu1A (Ap1m1). Comparison of their genomic structures revealed that the positions of introns are identical between these two genes, except for the insertion of an additional intron in Ap1m1 (intron 4). By contrast, these structures are different from that of the more distantly related Ap2m1 gene encoding mu2. Taken together with the similarity of amino acid sequences among these genes, the data presented in this study suggest that Ap1m1/2 and Ap2m1 diverged long before the separation of Ap1m1 and Ap1m2, which most likely resulted from a relatively recent gene duplication. We also mapped AP1M2 to human chromosome 19p13.2 and Ap1m2 to the proximal region of mouse chromosome 9. The results are consistent with the fact that these regions are syntenic.

Adaptor Protein Complex 1↗
PubMed1999

Gold alloys for resin bonding including small amount base metals--structural changes of alloy surface by the high-temperature oxidation.

To achieve durable bonding with adhesive resin, the surface roughness and the kinds of oxides, respectively to increase mechanical retention to enhance the chemical affinity of adhesive monomer with the gold alloy, were regulated by high-temperature oxidation together with the addition of small amounts of base metals. Alloys containing 2 mass% of Ni, In, or Cr with Cu were oxidized at 800 degrees C for 20 min in air, pickled in thioglycolic acid, and subsequently oxidized at 500 degrees C for 10 min in air. The morphology of the internal oxidation zone changed markedly according to the added base metals. Although the internal oxide particle composed of only Cu2O was removed by pickling, NiO, In2O3, and chromium oxides could not removed and remained on the alloy surface. The surface roughness was increased by addition of Ni, In, or Cr. Applying the present method can control the roughness and chemical states on a gold alloy surface to increase its adhesive ability with adhesive resins.

Acrylic Resins↗
PubMed1999

Relationship between Af temperature and load changes in Ni-Ti orthodontic wire under different thermomechanical conditions.

Simple three point bending tests were performed on Ni-Ti wires with three different Af points (1 degree C, 13 degrees C and 34 degrees C) to clarify the relationship between Af temperature and load changes under constant deformation. Each wire was deformed at 37 degrees C and then thermal changes were imposed by temperatures of 2 degrees C or 60 degrees C. The load changes with thermal changes from 37 degrees C to 2 degrees C or 60 degrees C showed the same tendency on the wires with different Af points: In the loading stage, the load became lower than the initial level at 37 degrees C and in the unloading stage, the load became higher than the initial load. The largest load change in the unloading stage was measured with the 13 degrees C Af point wire. Care must be taken when handling Ni-Ti wire with an Af point of less than 1 degree C in order to prevent it from reaching the limit of critical stress of slip deformation when the temperature in the mouth rises to above 40 degrees C.

Compressive Strength↗
PubMed1999

[Laparoscopic radical nephrectomy for renal cell carcinoma--transperitoneal anterior approach].

PURPOSE: To evaluate the usefulness of transperitoneal anterior approach in laparoscopic radical nephrectomy for patients with renal cell carcinoma. MATERIAL: Ten patients (Eight males and two females) with small renal cell carcinoma less than 7 cm in diameter were treated with laparoscopic radical nephrectomy between June 1997 and May 1999. Clinical stage was T1aN0M0 in 6 cases and T1bN0M0 in 4 cases. METHOD: Of the 10 patients, the initial four received preoperative embolization of the renal artery. Under general anesthesia laparoscopic radical nephrectomy via transperitoneal anterior approach was performed in all patients. This procedure facilitates initiated early access to the renal vessels as does open radical nephrectomy. The kidney was dissected en bloc with Gerota's fascia and delivered from the small skin incision without morcellation. RESULT: Two patients needed conversion to open surgery. The mean operating time of eight patients except for conversion cases was 247 minutes and the mean blood loss was 258 ml. There was no major complication associated with laparoscopic procedure. CONCLUSION: Transperitoneal anterior approach in laparoscopic radical nephrectomy is a suitable and useful procedure for the treatment of small renal cell carcinoma because it enables us to avoid possible tumor manipulation by early access to the renal vessels as open radical nephrectomy.

Adult↗
PubMed1999

t(9;14)(p13;q32) involving the PAX-5 gene: a unique subtype of 14q32 translocation in B cell non-Hodgkin's lymphoma.

Newly identified t(9;14)(p13;q32) is a subtype of the well-defined 14q32 translocation and is closely associated with lymphoplasmacytic lymphoma (Revised European-American Classification of Lymphoid Neoplasms). The analysis of the breakpoint of t(9;14) unraveled its molecular structure as being the recombination of the PAX-5 gene on 9p13 with IgH locus located on 14q32. The molecular event does not seem to cause structural alteration of the protein product of PAX-5 and, instead, its deregulation is most likely the essential outcome of this translocation. In vitro experiments have shown that the overexpression of PAX-5 resulted in enhanced proliferation of B cells, implicating its potential capacity for lymphomagenesis. PAX-5 is crucial during most developmental stages of B cells mainly through regulating the expression of a variety of genes. Therefore, elucidating the nature of the altered expression of these downstream genes as well as the PAX-5 gene itself would be indispensable in clarifying the precise mechanism of lymphomagenesis caused by t(9;14).

Animals↗
PubMed1999

[Itraconazole-induced hypokalemia in a patient with pulmonary aspergilloma].

An 80-year-old man was admitted to the hospital with a diagnosis of pulmonary aspergilloma. A new azole antifungal agent, D 0870, was administered to the patient for 7 days orally, and itraconazole (400 mg/day) was started on March 5, 1997. After 1 month of chemotherapy, facial and pretibial edema were observed and the patient's serum potassium concentration decreased to 2.5 mEq/l. A chest radiograph disclosed cardiomegaly with cardiac effusion and right pleural effusion on admission. The serum potassium concentration rose after the cessation of itraconazole therapy. The serum ITCZ concentration remained high for 2 weeks after admission. Although reports of hypopotassemia induced by ITCZ are rare, we concluded that blood concentrations should be monitored more carefully when treating pulmonary aspergilloma patients with high-dose regimens of ITCZ.

Aged↗
PubMed1999

[B cell acute lymphocytic leukemia with marked leukocytosis and t(3;15)(q27;q2?2)].

We report on a 16-year-old boy with B cell acute lymphocytic leukemia presenting marked leukocytosis (388,000/microliter) and resistance to multidrug chemotherapy. Karyotypical analysis revealed a novel t(3;15)(q27;q2?2) chromosomal abnormality. Because 3q27 is known to be a locus of the bcl-6 gene, which is frequently involved in B cell malignancies, molecular biological analyses were performed. Although no rearrangement was detected in 5 genes including bcl-6 on 3q27 and 2 genes on 15q2, reverse transcriptase-polymerase chain reaction procedures detected relatively strong mRNA expression of the bcl-6, smrp, dvl3, and tpml genes. These results indicate that immature leukemic cells with CD10 and CD34 positivity and rearrangement of the T cell receptor beta gene may coexist with relatively mature subpopulations that are positive for CD19 and CD20 surface markers, bcl-6 expression, and rearrangement of the gene for immunoglobulin kappa.

Adolescent↗
PubMed1999

[Factors for the onset of and the exacerbation of tuberculosis. 1. Activities in cytolysis and in apoptotic induction of mycobacteria on human THP-1 derived macrophage].

Cytolysis resulted in cell death was detected with propidium iodide, and apoptosis with Annexin V by using flow cytometry. The more vilurent strain in known murine infections showed the higher cytolytic activity. However in those mycobacterial strains that had the higher cytolytic activity on THP-1 cell, the lower level of apoptosis induction was observed. Addition of IFN-gamma or TNF-alpha to THP-1 derived macrophage did not effect on cytolytic activities nor apoptosis induction. Since mycobacteria with the higher cytolytic activity showed the lower apoptosis induction, it was suggested that apoptosis of human macrophage in mycobacterial infection is a beneficial phenomenon to the host.

Apoptosis↗