Search PubMed⌕ Search

Biomedical subjects

M Ohta

Publications and source records attributed to M Ohta.

At least 181 records · Page 10Linked to original sources
PubMed2000

Clinical and analytical evaluation of an enzyme immunoassay for myelin basic protein in cerebrospinal fluid.

BACKGROUND: RIA of myelin basic protein (MBP) in cerebrospinal fluid (CSF) is commonly used as a biochemical marker of demyelination in patients with multiple sclerosis (MS). Our aim was to develop a sufficiently sensitive ELISA for MBP and evaluate it clinically in patients with MS. METHODS: The ELISA used anti-bovine MBP antibody coated on plates and biotinylated anti-MBP antibody. The bound antibody complex was quantified with streptavidin-horseradish peroxidase. MBP was determined in CSF from 84 MS patients and 55 patients with other neurological diseases. RESULTS: The respective within- and between-assay CVs were 4.7% and 7.2% at 200 ng/L, and 6. 3% and 8.8% at 2000 ng/L. The detection limit was 30 ng/L. Most of the MS patients with acute exacerbations had markedly increased MBP in the CSF. Longitudinal studies of six MS patients with recurrent exacerbation confirmed this observation. MBP concentrations from 78 MS patients, as tested with our ELISA, correlated well with those obtained by RIA (r = 0.9; P: <0.01), but the detection limit of the ELISA was much lower than that of the RIA. CONCLUSIONS: This convenient ELISA with higher sensitivity than the existing assays is a suitable routine assay that provides a diagnostic indicator of myelin breakdown in the central nervous system; moreover, it is an excellent indicator of MS disease activity.

Adolescent↗
PubMed2000

[Tracheopulmonary-subcutaneous fistula associated with anaerobic subcutaneous abscess on mechanical ventilator support in a patient with Duchenne muscular dystrophy].

A 29-year-old Japanese man with Duchenne muscular dystrophy was placed on a mechanical ventilator support at 23 years of age and admitted to our hospital at 25 years of age. He had severe neck contracture deviated to the left side which resulted in dysphagia and microaspiration. At 29 years of age, he developed left lobar pneumonia accompanied by slight fever, back pain and a foul odor from the patient's sputum. Although the patient received broad spectrum antibiotics, pneumonia disseminated to the right lung. A week later, chest computed tomography was conducted which revealed tracheopulmonary-subcutaneous fistula, and a massive subcutaneous abscess with free air production. Drainage from the subcutaneous abscess was done through a chest tube; however, respiratory hypercapnia was not corrected and the patient died. From the culture of drained fluid, anaerobic bacteria including peptostreptococcus sp. were detected. This tracheopulmonary-subcutaneous fistula was thought to be caused by chronic microaspiration of mouth anaerobes, mechanical injury of the trachea under long term ventilator support, and decreased deep back muscle bulk with substitution of adipose tissue around the chest.

Abscess↗
PubMed2000

[Stress fracture].

Explore the source record for details and available documents.

Arthritis, Rheumatoid↗
PubMed2000

[Anesthetic management of two patients with polymyositis].

We report anesthetic experience of two patients suffering from polymyositis. The first case is a 56 year old woman who underwent tympanoplasty for cholesteatoma of the middle ear. Anesthesia was induced with thiopental and deepened with oxygen-nitrous oxide and sevoflurane. No muscle relaxant was used for endotracheal intubation and for maintaining anesthesia. Another is a 61 year old man who underwent open reduction and internal fixation for condyle fracture of the tibia. Epidural catheter was inserted at L 3-L 4. Epidural blockade was established with 2% mepivacaine, and sedation was achieved by intravenous midazolam. Concerning the anesthetic management of a patient with polymyositis, there are some informations on the appropriate use of muscle relaxants. It is generally believed that the patient is sensitive to nondepolarizing muscle relaxants and the use of antagonist drug (reversal) may cause muscle weakness, severe dysrhythmia, et al. Therefore we think it is appropriate to manage such a patient without muscle relaxants.

Anesthesia, Epidural↗
PubMed1999

Chloroplast ribonucleoproteins are associated with both mRNAs and intron-containing precursor tRNAs.

Tobacco chloroplasts possess five conserved ribonucleoproteins (cpRNPs). To elucidate the function of cpRNPs we analyzed their localization and target nucleic acid molecules in chloroplasts. Immunoprecipitation of the stromal extract and Northern analysis revealed that cpRNPs are associated in vivo with not only various species of chloroplast mRNAs but also intron-containing precursor (pre-) tRNAs. This observation strongly suggests that cpRNPs are involved in RNA processing, including mRNA stability and pre-tRNA splicing.

Blotting, Northern↗
PubMed1999

Changes in fructose-induced production of glucose in the rat liver following partial hepatectomy.

The fructose-induced production of glucose in the liver after partial hepatectomy (PH) was evaluated by using the liver-perfusion system. There was no significant difference in plasma glucose level between hepatectomized (HX) and sham-operated (SO) rats at 24 h after surgery, and, thereafter, almost similar levels were obtained in both groups. However, the level of serum free fatty acids (FFA) was significantly higher in HX rats than that in SO rats at 24 and 48 h after surgery. When both groups of rats were given fructose by gavage, the increment of plasma glucose was significantly larger in HX rats than in SO rats. Lactate infusion failed to increase the rate of glucose production in perfused livers of both HX and SO rats and there was no significant difference in the activity of hepatic phosphoenolpyruvate carboxykinase. By contrast, fructose infusion elicited a large increase in glucose production in the perfused livers of HX rats at 24 and 48 h after PH. The increase was closely associated with not the change in fructose 2,6-bisphosphate levels but the increment of the intracellular levels of citrate. Treatment of octanoate or oleate, which supplies acetyl-CoA via fatty acid oxidation, mimicked the fructose-induced increase in glucose production in SO rats with a concomitant increase in hepatic levels of citrate. These results suggest that the oxidation of FFA may play an important role in glucose production induced by fructose administration during the early phase of liver regeneration.

Acetyl Coenzyme A↗
PubMed1999

Role of multiple efflux pumps in Escherichia coli in indole expulsion.

Escherichia coli chromosome encodes several multidrug transporters. Despite their protective function against antibacterial agents, the specific physiological actions of these transporters are not fully understood. E. coli produces indole, a metabolite of tryptophan, under physiological conditions. Defined inactivation of the acrEF gene, the product of which is known as an energy-dependent multiple drug efflux pump, decreased indole excretion while reintroduction of the acrEF gene restored it. A DeltaacrEF mutant accumulated more intracellular indole than the parent. This mutant was more susceptible to the growth-inhibitory effect of indole than the parent. These results indicate that the AcrEF system plays a significant role in indole efflux.

Carrier Proteins↗
PubMed1999

Alterations in monoamines and GABA in the ventromedial and paraventricular nuclei of the hypothalamus following cold exposure: a reduction in noradrenaline induces hyperphagia.

A microdialysis technique for the in vivo assessment of the monoaminergic and GABAergic levels in the ventromedial (VMN) and paraventricular nuclei (PVN) of the hypothalamus was used in order to examine the activities of neurons that project to the hypothalamic regions and are implicated in the regulation of ingestive behavior and energy balance. Cold exposure increased food intake, as well as the circulating levels of glucose, noradrenaline (NA), 3,5,3'-triiodothyronine, and corticosterone. The dialysate concentrations of NA, dopamine (DA), serotonin (5-HT), and gamma-aminobutyric acid (GABA) in the VMN all decreased after exposure to cold. The changes in extracellular NA, DA, and GABA in the PVN under cold conditions were similar to those in the VMN. NA release in the VMN or PVN was decreased after local electrolytic lesions, which significantly increased food intake. Thus, low activities of noradrenergic axons of neurons terminating in the VMN and PVN may be a good mechanism to induce feeding behavior. Extracellular 5-HT in the PVN was significantly increased, along with a significant decrease in 5-hydroxyindoleacetic acid, in cold-exposed rats, suggesting that serotonergic fibers terminating in the PVM are more closely related to the increases in adrenocortical and thyroid hormone secretion than to food intake. The neuronal activities, indicating that a sympathetic tone is activated on stimulation of the VMN and/or PVN, may be changes in GABAergic and/or serotonergic neurons.

Animals↗
PubMed1999

Changes in hepatic nitrogen metabolism in isolated perfused liver during the development of thioacetamide-induced cirrhosis in rats.

Changes in hepatic nitrogen metabolism in isolated perfused liver were studied during the induction of experimental cirrhosis by thioacetamide in female Sprague-Dawley rats. Cirrhosis of the micronodular type developed during 12-week administration of thioacetamide. Despite an increase in food consumption for 4 weeks after the end of administration, the physiological changes characteristic of cirrhosis were maintained. The rate of urea excretion per unit liver weight was significantly decreased compared with pair-fed control rats both during and after thioacetamide treatment. During 4 weeks of thioacetamide treatment, the rate of urea production in perfused liver from a combination of 0.25 mM NH4Cl and 1 mM glutamine decreased slightly, without a decrease in the maximum rate of urea production from 10 mM NH4Cl. In cirrhotic rats, the rate of urea production in perfused liver from NH4Cl and/or glutamine decreased, with a decrease in the maximum rate of urea production. The Km of ureagenesis for NH3 was unchanged in cirrhotic livers. During 4 weeks of thioacetamide treatment, glutamate dehydrogenase activity decreased, but the thioacetamide-induced cirrhotic state had no effect on glutamate dehydrogenase or glutaminase activity. Glutamine synthetase activity was decreased in rats treated with thioacetamide for 4 or 12 weeks. These results are consistent with the hypothesis that the capacity for urea production from NH3 and amino acids is decreased in the development of cirrhosis.

Alanine Transaminase↗
PubMed1999

Analysis of carbohydrate heterogeneity in a glycoprotein using liquid chromatography/mass spectrometry and liquid chromatography with tandem mass spectrometry.

High-performance liquid chromatography with on-line electrospray ionization mass spectrometry (ESI-LC/MS) was investigated for the analysis of carbohydrate heterogeneity using RNase B as a model glycoprotein. Oligosaccharides released from RNase B with endoglycosidase H were reduced and separated on a graphitized carbon column (GCC). GCC-HPLC/MS in the positive-ion mode was successful in the identification of one Man5GlcNAc, three Man6GlcNAc, three Man7GlcNAc, three Man8GlcNAc, one Man9GlcNAc, and an oligosaccharide having six hexose units (Hex) and two N-acetylhexosamine units (HexNAc). The branch structures of the three Man7GlcNAc isomers were determined by liquid chromatography with tandem mass spectrometry (LC/MS/MS). LC/MS/MS analysis was shown to be useful for the detection and identification of a trace amount of Hex6HexNAc2 alditol as a hybrid-type oligosaccharide. Its structure was confirmed by the combination of LC/MS with enzymatic digestion using beta-galactosidase and N-acetyl-beta-glucosaminidase. The relative quantities of high-mannose-type oligosaccharides in RNase B detected by ESI-LC/MS are in reasonable agreement with those by UV, high-pH anion-exchange chromatography with pulsed amperometric detection, fluorophore-assisted carbohydrate electrophoresis. Our results indicate that LC/MS and LC/MS/MS can be utilized to elucidate the distribution of oligosaccharides and their structures, which differ in molecular weight, sugar sequence, and branch structure.

Animals↗
PubMed1999

Four critical aspartic acid residues potentially involved in the catalytic mechanism of Escherichia coli K-12 WaaR.

Escherichia coli K-12 WaaR is a non-processive alpha-1,2 glucosyltransferase, involved in the synthesis of the R-core of lipopolysaccharide. WaaR possesses the four conserved structural regions I, II, III and IV, each presumably involved in the mechanistic function in catalysis. Regions I and III contain the pair of strictly conserved Asp residues. Asp-129, 131 (region I) and 215, 217 (region III) of WaaR were individually converted to Asn by the site-directed mutagenesis of the waaR gene. All mutated enzymes were inactive, supporting the model for an alpha-glycosyl transfer reaction where the pair of strictly conserved aspartic acid residues in regions I and III play a critical role in the catalytic function.

Aspartic Acid↗
PubMed1999

Sequence analysis of genomic regions containing trinucleotide repeats isolated by a novel cloning method.

A method was developed for effective isolation of trinucleotide repeats from genomic DNA. This method is based on the DNA polymerase reaction, which is restricted with only two or three nucleotide substrates and primed by biotinylated oligonucleotide probes. Sequences are then isolated by a streptavidin biotin-trapping method. More than 80% of the clones from each library contained more than eight trinucleotide repeats. Sequence analysis showed that the characteristic dinucleotide flanking sequences usually confronting various trinucleotide repeats are not found in the vicinity of CAG repeats, suggesting that CAG repeats may have been generated through a mechanism different from that of other trinucleotide repeats.

Blood↗
PubMed1999

Characteristics of nitrogen metabolism in rats with thioacetamide-induced liver cirrhosis.

Female Sprague-Dawley rats were given 0.03% thioacetamide (TAA) in their drinking water daily for 4 or 12 weeks, and were then given normal water for 4 weeks after the end of a 12-week TAA treatment to investigate amino acid metabolism. In the malnourished precirrhotic stage (stage 1) and the malnourished cirrhotic stage (stage 2), the aromatic amino acids (AAA), Glu, Asp, Orn, Arg and Cit increased, and the branched-chain amino acids (BCAA) decreased slightly. Because these changes normalized in the well-nourished cirrhotic stage (stage 3), they might have resulted from impairment of hepatocytes and malnutrition. The net uptake of BCAA into the liver increased in stage 2, but the AAA uptake did not exceed that in normal controls. Portal venous plasma AAA increased to the same level as arterial plasma AAA. These results suggest that the decrease in BCAA was partially due to liver uptake and that the increase in AAA was induced by reduction of liver uptake and overproduction in extrahepatic tissues. The liver contents of BCAA and AAA were unchanged in all stages, so were fully utilized in the impaired liver. The increases in Glu, Asp, Orn and Cit might have resulted from overproduction in the liver, because these contents of the liver increased in stage 2. In conclusion, the changes in amino acid metabolism in rats with cirrhosis induced by TAA closely resemble those seen in human liver cirrhosis.

Amino Acids↗
PubMed1999

High sensitivity of the ultraviolet-induced p53 response in ultraviolet-sensitive syndrome, a photosensitive disorder with a putative defect in deoxyribonucleic acid repair of actively transcribed genes.

Previously, we reported a new category of photosensitive disorder named ultraviolet-sensitive syndrome (UVs S) [T. Itoh, T. Fujiwara, T. Ono, M. Yamaizumi, UVs syndrome, a new general category of photosensitive disorder with defective DNA repair, is distinct from xeroderma pigmentosum variant and rodent complementation group 1, Am. J. Hum. Genet. 56 (1995) 1267-1276.]. Cells derived from these patients show impaired recovery of RNA synthesis (RRS) after UV-irradiation irrespective of having a normal level of unscheduled DNA synthesis (UDS). These characteristics are reminiscent of Cockayne syndrome (CS) cells. By comparing sensitivity of the UV-induced p53 response in cells with different types of defects in nucleotide excision repair, we hypothesized that the UV-induced p53 response is triggered by inhibition of RNA synthesis [M. Yamaizumi, T. Sugano, UV-induced nuclear accumulation of p53 is evoked through DNA damage of actively transcribed genes independent of the cell cycle, Oncogene 9 (1994) 2775-2784.]. To test this hypothesis, we determined sensitivity of the p53 response in UVs S cells by immunostaining, Western blotting, and FACScan analysis. Maximal nuclear accumulation of p53 in the UVs S cells was observed with a one-third UV dose required for that in normal cells, while almost identical p53 responses were observed in UVs S and normal cells following treatment with heat or alpha-amanitin. Recovery of RNA synthesis after a low dose of UV-irradiation was impaired in UVs S cells to the same extent as seen in CS cells. These results provide further evidence to support our previous hypothesis regarding the mechanism of the p53 response induced by DNA damage.

Amanitins↗
PubMed1999

Analysis of postoperative complications after esophagectomy for esophageal cancer in patients receiving neoadjuvant therapy.

Postoperative complications were investigated in 72 patients who received neoadjuvant therapy with esophagectomy. Preoperative chemotherapy consisted of 5-fluorouracil (700 mg/m2/day, on days 1 to 5), cisplatinum (70 mg/m2/day, on day 1) and leucovorin (20 mg/m2/day, on days 1 to 5). Preoperative chemoradiotherapy consisted of cisplatinum combined chemotherapy and radiotherapy (total dosage of 30-70 Gy). The incidence of postoperative pneumonia (16%) and anastomotic leakage (24%) in the preoperative chemotherapy group was slightly higher than that in the control group (n = 506), and mortality (6.0%) after esophagectomy in the preoperative chemotherapy group was higher than that (2.4%) of the control group. Postoperative morbidity and mortality were observed more frequently in patients who received two cycles of the chemotherapy than those receiving only one cycle. Postoperative complications occurred more frequently in patients suffering high grade toxicities due to the preoperative chemotherapy. The highest preoperative serum creatinine value correlated to that of postoperative period (r = 0.6494). The use of the preoperative chemoradiotherapy with a total exposure dosage of 60 Gy or more significantly increased the postoperative pneumonia rate (67%; p < 0.05) compared to the group receiving 40 Gy or less. The mortality rate (33%) also increased. The second cycle of the preoperative chemotherapy should be cancelled if patients suffer high grade toxicities during or after the first cycle, and the total exposure dosage of the preoperative chemoradiotherapy should be limited to 40 Gy or less.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1999

Genetic contribution of the BAT2 gene microsatellite polymorphism to the age-at-onset of insulin-dependent diabetes mellitus.

The BAT2 gene lies within the class III region of the major histocompatibility complex. We investigated the frequency of the BAT2 microsatellite alleles (BAT2) in 74 young-onset insulin-dependent diabetes mellitus (IDDM) patients, 51 adult-onset IDDM patients, and 85 normal control subjects, and assessed the associations among these BAT2 alleles, TNFa microsatellite alleles (TNFa), and HLA-DRB1 alleles. The frequency of the BAT2.9 allele was significantly increased in the young-onset IDDM patients (12.8 vs 4.1%, Pc=0.04896), whereas the frequency of BAT2.12 allele was significantly decreased in young-onset IDDM patients (0.0 vs 11.8%, Pc=0.00002) compared with control subjects. The BAT2.9 allele was strongly associated with TNFa9 in the young-onset IDDM patients, although no association was found between the BAT2.9 and HLA-DRB1 alleles. The BAT2.12 allele was strongly associated with TNFa13, and with DRB1*1502 in control subjects. These results suggest that the BAT2 microsatellite polymorphism is associated with the age-at-onset of IDDM and possibly with the inflammatory process of pancreatic beta-cell destruction during the development of IDDM. However, this association is not independent of TNFa polymorphisms.

Adolescent↗