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T Ohmura

Publications and source records attributed to T Ohmura.

At least 19 recordsLinked to original sources
PubMed2006

Plasma level of a 5-fluorouracil metabolite, fluoro-beta-alanine correlates with dihydropyrimidine dehydrogenase activity of peripheral blood mononuclear cells in 5-fluorouracil treated patients.

5-fluorouracil (5-FU) is mostly metabolized after administration, and the metabolizing enzyme, dihydropyrimidine dehydrogenase (DPD), seems to be the rate-limiting factor. However, there are few reports on the final metabolite, fluoro-beta-alanine (FBAL). We report here the results of determination of the FBAL level in 5-FU treated patients and the correlation between the FBAL level and the DPD activity in peripheral blood mononuclear cells (PBMCs). Blood samples were collected from 20 patients, who had received continuous intravenous infusion (CIV) of 5-FU (320 mg/m2/24 hr) after resection of colorectal cancer, and the FBAL level was determined by high performance liquid chromatography (HPLC), after derivatizing into o-phthalaldehyde (OPA) and detecting fluorescence. DPD activity was measured in cytosol prepared from PBMCs using HPLC radioassay. The average FBAL plasma level during CIV of 5-FU was 911.0 ng/ml (521.0 to approximately 1834.6 ng/ml) and that of DPD activity in PBMCs was 282.6 pmol/min/mg-protein (145.0 to approximately 568.0 pmol/min/mg-protein). There was a significant correlation between the FBAL level and the DPD activity (r=0.805, p<0.0001). FBAL level in plasma may be useful in predicting the DPD activity in PBMCs, however, further studies are required considering the small number of cases in this study.

Aged↗
PubMed2003

Identification of the region in Escherichia coli DnaA protein required for specific recognition of the DnaA box.

DnaA protein binds specifically to a 9-base- pair motif called the DnaA box. Domain IV comprises 94 amino acid residues and is required for DNA binding. Using nuclear magnetic resonance analysis, we investigated the interaction between DnaA domain IV and both a DnaA box and a non-specific oligonucleotide that has a reduced affinity for DnaA. The 1H-15N HSQC spectrum of DnaA domain IV showed prominent chemical shift perturbations on six residues (Arg399, Ala404, Leu422, Asp433, Thr435 and Thr436) in the presence of the DnaA box. Through homology modeling, we located all of these residues on one side surface of the DnaA domain IV molecule. Moreover, we compared the chemical shift perturbation of the 1H-15N HSQC spectrum in the presence of the DnaA box with that in the presence of a non-specific oligonucleotide, and the results suggested that Leu422 imparts specificity in binding with the DnaA box.

Amino Acid Sequence↗
PubMed2003

Start-up of full-scale anaerobic digesters treating municipal solid waste.

Raising organic loading rate, and the behavior of dissolved CODcr (D-CODcr), VFA and specific methanogen activity, were investigated through a laboratory experiment for the start-up of a sludge recycling center. Moreover, application for MPN-PCR methods using a gene as a direct technique to measure the quantity of methanogen was attempted. It was recognized that specific methanogen activity depends on the quantity of methanogen, and that gas production does not reflect the condition of methane fermentation. The methane fermentation condition was checked through the specific methanogen activity and analysis of D-CODcr. The target organic loading rate was reached in the short period of about 30 days, and rapid start-up was successfully attained for a full-scale anaerobic digester.

Bacteria, Anaerobic↗
PubMed2002

Relationship between head orientation and torsional eye movements in goldfish during linear acceleration.

We analyzed torsional eye movements of normal goldfish during sinusoidal linear acceleration, altering the orientation of the fish on the linear accelerator in the yaw plane over a range of 90 degrees and in the pitch plane up to 30 degrees. We video-recorded changes of torsional eye movements associated with a body rotation in the yaw and pitch plane and analyzed them frame by frame. In normal fish, we observed clear torsional eye movements for stimuli of 0.1 G linear accelerations along the body axis in the horizontal position. Torsion occurred in the opposite direction of resultant force produced by linear acceleration and gravity. Though the amplitude of these compensatory responses increased with increasing magnitude of acceleration up to 0.5 G, the torsion angle did not fully compensate the angle calculated from gravity and linear acceleration. Furthermore, the torsion angle decreased as the longitudinal body axis deviated from the direction of linear acceleration. For the body axis perpendicular to the direction of acceleration, torsional eye movement was still observed. When we tilted the fish in the pitch plane, compensatory eye torsion occurred. The response amplitude to acceleration decreased for both head-up and head-down up to 30 degrees. These results suggested the existence of specific connections between the otolith organ and ocular muscles.

Acceleration↗
PubMed2001

A congenital dermal sinus presenting the muscle fasciculation and hypertrophy.

OBJECTIVE: To report unique and unknown clinical features of muscle fasciculation and muscle hypertrophy in a case of congenital dermal sinus. PATIENTS: A 16-year-old girl presented with continuous fasciculation, often cramp, and hypertrophy of the left calf muscle. The radiography showed spina bifida of L4, L5 and S1. MRI revealed dermal sinus tract from the skin dimple of the back to the dura mater, and connected to the intradural inclusion tumor. At surgery the inclusion tumor contained many short hairs, and the cauda equina were severely adherent. Microdissection of the tumor and the adhesion was performed. At 2 years after surgery fasciculation decreased but continued; however, painful cramps of the calf muscle do not occur. CONCLUSIONS: Short hairs of dermoid and the adherence might be irritative to the cauda equina. The hyperactivity of the stimulated motor neuron may cause the muscle fasciculation leading to hypertrophy of the calf muscle.

Adolescent↗
PubMed2001

Distal cement mantle thickness with a triangular distal centralizer inserted into the stem tip in cemented total hip arthroplasty.

Fifty-seven hips undergoing a primary cemented total hip arthroplasty with use of a triangular distal centralizer inserted into the stem tip were investigated, with a special focus on distal cement mantle thickness. The subjects were 43 women and 3 men. When evaluated on conventional anteroposterior and lateral radiographs, the relative incidence of thin cement mantles in zones 3 or 5 owing to the distal centralizer was 15.8% (9 hips). Unsatisfactory findings were that the distal centralizer and distal part of the stem shifted to the cortex in 7 hips and bent or failed at the inserted site in 2 hips. There is risk of generating a thin cement mantle with use of the triangular centralizer and its insertion into the stem tip.

Adult↗
PubMed2001

Tolerance of point substitution of methionine for isoleucine in hen egg white lysozyme.

X-ray structure determination of proteins by using the multiple-wavelength anomalous dispersion method targeting selenomethionine is now widely employed. Isoleucine was examined for the second choice of the substitution of methionine next to leucine. We performed a systematic mutational study of the substitutions of methionine for isoleucine. All mutated lysozymes were less stable than the wild-type by about 1 kcal/mol and it is suggested that this instability was caused by the change in residual hydrophobicity from isoleucine to methionine. The X-ray structures of all mutant lysozymes were very similar to that of the wild-type. In addition, both the accessible surface areas and the conformation of the side chain of methionine in all mutant lysozymes were similar to those of the side chain at the respective isoleucine in the wild-type. Therefore, it is suggested that the mutation from isoleucine to methionine in a protein can be considered as a "safe" substitution.

Amino Acid Substitution↗
PubMed2001

Stabilization of hen egg white lysozyme by a cavity-filling mutation.

Stabilization of a protein using cavity-filling strategy has hardly been successful because of unfavorable van der Waals contacts. We succeeded in stabilizing lysozymes by cavity-filling mutations. The mutations were checked by a simple energy minimization in advance. It was shown clearly that the sum of free energy change caused by the hydrophobicity and the cavity size was correlated very well with protein stability. We also considered the aromatic-aromatic interaction. It is reconfirmed that the cavity-filling mutation in a hydrophobic core is a very useful method to stabilize a protein when the mutation candidate is selected carefully.

Animals↗
PubMed2001

Detection of hypermethylation of the p16(INK4A) gene promoter in chronic hepatitis and cirrhosis associated with hepatitis B or C virus.

BACKGROUND/AIM: Inactivation of the p16(INK4A) (p16) tumour suppressor gene by promoter region hypermethylation has been demonstrated not only in many types of tumours, including hepatocellular carcinoma (HCC), but also in early preneoplastic lesions in the lung, colon, oesophagus, and pancreas. The aim of this study was to examine the methylation status of the p16 promoter in pre- and/or non-neoplastic liver diseases. PATIENTS/SUBJECTS/METHODS: The methylation status of p16 was evaluated in 22 HCC, 17 cirrhosis, 17 chronic hepatitis, nine primary biliary cirrhosis (PBC), eight autoimmune hepatitis, seven drug induced liver disease, six fatty liver, and three normal liver tissues using methylation specific polymerase chain reaction (MSP). p16 protein expression was also examined by immunohistochemical staining. RESULTS: Methylation of the p16 promoter was detected in HCC (72.7%, 16/22) and also in cirrhosis (29.4%, 5/17) and chronic hepatitis (23.5%, 4/17), all of which were positive for hepatitis B or C virus infections. Methylation was not detected in any of the other samples. All methylation positive HCC, cirrhosis, and chronic hepatitis samples showed loss of p16 expression, and a significant correlation was found between methylation and loss of expression. Analysis of serial samples from individual patients with methylation positive HCC revealed that loss of p16 expression with promoter methylation occurred in 18 of 20 patients at the stage of chronic hepatitis without clinically detectable carcinoma. CONCLUSIONS: Our results suggest that methylation of the p16 promoter and the resulting loss of p16 protein expression are early events in a subset of hepatocarcinogenesis and that their detection is useful in the follow up of patients with a high risk of developing HCC, such as those with hepatitis B or C viral infections.

Adult↗
PubMed2001

Increase in doxorubicin cytotoxicity by inhibition of P-glycoprotein activity with lomerizine.

Acquired resistance to chemotherapy is a major problem during cancer treatment. One mechanism for drug resistance is overexpression of the MDR (multidrug resistance)1 gene encoding the transmembrane efflux pump, P-glycoprotein (P-gp). Calcium channel blockers such as verapamil, nifedipine and nicardipine have been shown to reverse cellular drug resistance by inhibiting P-gp drug efflux. This study evaluated whether a new calcium channel blocker, lomerizine, influenced doxorubicin (Dox) cytotoxicity and P-gp activity in a P-gp-expressing cell line compared to a non-expressing subline. Verapamil, and even more markedly, lomerizine, increased cellular uptake of calcein transported by P-gp in a P-gp-expressing erythroleukemia cell line, K562-Dox. Ten microM of lomerizine reduced the IC50 of doxorubicin in the K562-Dox from 60000 ng/ml to 800 ng/ml, whereas the IC50 of doxorubicin in the K562 subline was only marginally affected by these drugs. Lomerizine showed greater reduction in P-gp efflux than verapamil at an equimolar concentration. These results suggest that lomerizine has the clinical potential to reverse tumor MDR involving the efflux protein P-gp.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2001

Studies on the effects of microgravity on the ultrastructure and function of cultured mammalian cells.

Four cultures of monkey kidney cell line, JTC-12, were flown on the Spacelab-J (SL-J) mission during 8 days. The results of the present study showed that the space flight gave no essential effect on morphology, cell cycle, glucose consumption and urokinase production of the mammalian culture cell. However, the cell proliferation slightly decreased under microgravity. Moreover, the lack of gravity induced the trypsin-treated dissociated cells to keep floating in the culture medium. Therefore, the attachment of the cells onto the substratum was delayed, and that caused difficulties in subculturing the cells. The present research also offered some important information on techniques for establishment of cell cultures in space laboratories.

Animals↗
PubMed2000

Gastric varices with splenic vein occlusion treated by splenic arterial embolization.

A 53-year-old man was admitted to our hospital in August 1997 with enlarged gastric varices. Computed tomography (CT) showed splenic vein occlusion, gastric varices, and extra-gastric wall collateral veins. Color flow images of gastric varices were clearly visualized, and the velocity in the gastric varices was 19.6 cm/s via endoscopic color Doppler ultrasonography (ECDUS). The patient was diagnosed with gastric varices according to angiographic findings of splenic vein occlusion, and splenic arterial embolization was performed. Two weeks after the splenic arterial embolization, CT showed peripheral areas of low attenuation in the spleen, due to splenic infarction, with 70% of the spleen volume showing low attenuation. Eight months after the splenic arterial embolization, ECDUS revealed a decrease in gastric variceal color flow images, with the velocity in the gastric varices being 10.3 cm/s.

Chronic Disease↗
PubMed2000

High-level expression of recombinant human serum albumin from the methylotrophic yeast Pichia pastoris with minimal protease production and activation.

The methylotrophic yeast, Pichia pastoris, is widely used as a host strain for the production of a variety of heterologous proteins. We used P. pastoris for the production of recombinant human serum albumin (rHSA). In several runs of fed-batch fermentation, rapid degradation of rHSA was observed, coinciding with a sudden increase of protease activity in the culture broth. Monitoring the changes in the concentration of the medium components during fermentation suggested that this phenomenon was caused by nitrogen starvation. Increased initial concentrations of ammonia and phosphoric acid in the medium prevented the protease production during fermentation. Using this improved medium, stable production of rHSA of around 1.4 g/l was achieved. Although protease activity in the culture broth of the improved medium was not detected by the casein plate method at the end of fermentation, potential protease activity remained and could be activated by decreasing the pH of the culture broth, a high degradation rate of 660 mg HSA/l/h was observed at pH 4.3, but degradation did not occur above pH 5.9.

Journal Article↗
PubMed2000

Early mutation of precore (A1896) region prior to core promoter region mutation leads to decrease of HBV replication and remission of hepatic inflammation.

To evaluate the relationship between mutations and clinical courses, we investigated precore (preC) and core promoter (CP) mutations and serum HBV DNA levels in HBe-antibody-positive HBV carriers. Fifty-six asymptomatic carriers (ASC), 29 patients with chronic hepatitis who showed normal ALT levels for more than two years (CH-ASC), 31 patients with chronic hepatitis (CH), and 32 patients with hepatocellular carcinoma (HCC) were studied. Almost all patients (99.2%) had mutations in either CP or preC. Mutation only in preC (A1896) was present in 52.2% with ASC, 25.0% with CH-ASC, 16.1% with CH, and 8.0% with HCC, and was significantly higher in ASC (P < 0.01). The patients with only preC mutation showed low HBV DNA levels in each clinical stage. The mutation of preC (A1896) prior to the mutation of CP might control the replication of HBV, which leads to the remission of hepatitis.

Adult↗
PubMed2000

Infrequent widespread microsatellite instability in hepatocellular carcinomas.

Widespread or high-frequency microsatellite instability (MSI) due to the defective DNA mismatch repair (MMR) occurs in the majority of hereditary non-polyposis colorectal cancer and a subset of sporadic malignant tumors. The incidence of MSI and underlying DNA MMR defects have been well characterized in gastrointestinal carcinogenesis, but not in hepatocarcinogenesis. To address the issue, we analyzed 55 Japanese hepatocellular carcinomas using several indicators of DNA MMR defects, such as microsatellite analysis, loss of heterozygosity (LOH) and mutation analysis of MMR genes, methylation of hMLH1 promoter, and frameshift mutations of mononucleotide repeat sequences within possible target genes. Mutation of beta2-microglobulin gene, which is presumably involved in MSI-positive tumor cell escape from immune surveillance was also examined. Some of these analyses were also carried out in 9 human liver cancer cell lines. None of the 3 quasi-monomorphic mononucleotide markers sensitive for MSI, BAT26, BAT25, and BAT34C4 presented shortened unstable alleles in any of the carcinoma, cirrhosis, chronic hepatitis tissues, or cell lines. LOH at MMR genes was infrequent (4.4 approximately 7.1%), and no mutations were detected. Neither hMLH1 hypermethylation nor frameshift mutation in the target genes was detected. No mutations were found in beta2-microglobulin. Widespread MSI due to the defective DNA MMR appears to play little if any part in Japanese hepatocarcinogenesis.

Adult↗
PubMed2000

[Clinical study of selective intra-arterial infusion chemotherapy using trans-radial arterial approach in 4 cases of advanced breast cancer].

We administered neoadjuvant chemotherapy by a selective intra-arterial infusion method using a trans-radial approach in patients with advanced breast cancer (stage III and stage IV). The trans-radial approach uses the arterial flow, based on the Seldinger technique. In this method, the radial artery is cannulated, and epirubucin is infused into the artery that carries blood from the subclavical artery to the breast. We have used this method in 4 cases thus far. Two of the patients received a single intra-arterial infusion of epirubicin. The other 2 patients were catheterized before they received chemotherapy by intra-arterial infusion. This technique decreased the pain or discomfort caused by the catheterizations during chemotherapy in all 4 cases. However, the currently available catheters are not always able to approach the artery flowing into the breast, thus the protocol will need to be refined.

Adenocarcinoma, Scirrhous↗
PubMed2000

Relationship of high-density lipoprotein cholesterol and red blood cell filterability: cross-sectional study of healthy subjects.

The deformability of red blood cells (RBCs) is an important rheologic factor in the maintenance of normal blood flow in the microcirculation. Contrary to the well-known relationship between hyperlipidemia and atherosclerosis, the relationship between RBC rheology and the serum lipid profile has remained controversial and obscure. Moreover, the correlation of high-density lipoprotein (HDL)-cholesterol and RBC deformability has not been fully understood. In the present cross-sectional study of 139 apparently healthy subjects, we investigated whole-cell deformability (filterability) of RBCs in relation to the lipid profile, using a nickel mesh filter with 3.2-microm pores. RBC filterability was independent of gender, age and serum levels of low-density lipoprotein (LDL)-cholesterol. The filterability was significantly proportional to the HDL-cholesterol values (r = 0.382, p < 0.01), whereas it was inversely proportional to the triglyceride levels (r = -0.259, p < 0.01). These findings may provide new insight into the role of HDL-cholesterol not only in preventing atherosclerotic progression but also in improving RBC filterability.

Adult↗