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M Ohta

Publications and source records attributed to M Ohta.

At least 631 records · Page 35Linked to original sources
PubMed1993

Isolation of rfb gene clusters directing the synthesis of O polysaccharides consisting of mannose homopolymers and serological analysis of lipopolysaccharides.

Four serotypes of two genera, Escherichia coli O8 and O9 and Klebsiella O3 and O5, produce the O polysaccharides consisting of mannose homopolymers. Previously, we reported the isolation and expression of E. coli O9 rfb in E. coli K-12 strains (Kido et al, J. Bacteriol., 171: 3629-3633, 1989). In this study, R' plasmids carrying his-rfb region of the other three strains were isolated and expressed in E. coli K-12 strain. Serological study of lipopolysaccharides (LPS) synthesized in E. coli K-12 strain was carried out. His-linked rfb genes from E. coli O9 and Klebsiella O3 directed the synthesis of O polysaccharides with the same antigenicity as those of the parental strains in E. coli K-12 strain. On the other hand, rfb genes from E. coli O8 and Klebsiella O5 directed the synthesis of O polysaccharides which were antigenically not identical but partially common to those of the parental strains. A rough strain derived from E. coli O8 synthesized LPS which showed the identical antigenicity as the wild strain when the his-rfb region of E. coli O8 was introduced. The results suggest that some genes located distantly from his are additionally required to complete the synthesis of O polysaccharides of E. coli O8 and Klebsiella O5.

Carbohydrate Conformation↗
PubMed1993

A case of squamous cell lung carcinoma with high concentration of parathyroid hormone-related peptide in serum and pleural effusion presenting hypercalcemia.

A 57-year-old man with lung squamous cell carcinoma revealed hypercalcemia, hypophosphoremia, elevation of nephrogenous cAMP and metabolic alkalosis. Serum parathyroid hormone (PTH) and 1,25(OH)2D3 concentrations were not elevated. These findings were consistent with those in humoral hypercalcemia of malignancy (HHM). PTH-related peptide (PTHrP) concentrations were determined using N- and C-terminal specific radioimmunoassays (PTHrP-N, PTHrP-C), and elevation of both PTHrP-N and PTHrP-C concentrations in the serum was noted (PTHrP-N, 27 pmol/liter (normal < 5); PTHrP-C, 1408 pmol/liter (normal < 50)). High concentration of PTHrP (946 pmol/liter for PTHrP-N and 5983 pmol/liter for PTHrP-C) was also found in the pleural fluid obtained at autopsy. Immunohistochemical study, using paraffin-embedded sections of the tumor tissue obtained at autopsy, revealed numerous PTHrP-positive cells and expression of PTHrP gene was confirmed by Northern blot analysis. These findings indicate that PTHrP, produced in the tumor tissue, was secreted into the blood stream, which caused HHM in the patient. Gel permeation chromatography of the serum and pleural fluid revealed several peaks of both PTHrP-N and PTHrP-C. Molecular forms of PTHrP-N were larger than those of PTHrP-C in the serum as well as pleural fluid. These findings indicate that multiple forms of PTHrP molecules are present in the serum and pleural fluid. Granulocytosis was also noted in the patient. However, granulocyte- and granulocyte macrophage-colony stimulating factor were not detected in the serum, and the mechanism of the granulocytosis in the patient was unclear.

Blotting, Northern↗
PubMed1993

Brefeldin A blocks the cytotoxicity of T cell receptor alpha/beta and gamma/delta cytotoxic T lymphocyte clones reacting against human autologous cancer cells.

We studied the effector mechanism of T cell receptor (TCR) alpha/beta- and gamma/delta-type cytotoxic T lymphocyte (CTL) clones that react with human autologous tumor cells. Treatment of tumor cells with a fungal antibacterial reagent, brefeldin A (BFA), resulted in the inhibition of cytotoxicity of an autologous tumor (HST-2)-specific CD8+ TCR alpha/beta-type CTL, TcHST-2. Other anti-metabolites such as chloroquine, cycloheximide and colchicine did not affect the cytotoxicity. The cell-surface antigen expression, including MHC class I molecules, was not influenced by BFA treatment. Furthermore, BFA did not influence the cytotoxicity of lymphokine-activated killer cells and natural killer cells. Since BFA blocks the transport of peptides from endoplasmic reticulum to the Golgi apparatus, the above data suggest that BFA could affect washing out of the peptide fragments from the MHC class I groove. Consequently, target tumor cells were protected from killing by CTL. Moreover, we obtained a CD4-, 8-, TCR gamma/delta-type (V delta 1+) CTL clone, TcHOT, that reacts against an autologous ovarial carcinoma, HOT. BFA could also inhibit this cytotoxicity, and it is likely that different presenting molecules other than MHC class I proteins participate in the cytotoxicity of this TCR gamma/delta-type CTL. These studies suggest that both TCR alpha/beta- and gamma/delta-type CTL may require antigenic peptides that are most likely derived from the BFA-sensitive, intracellular endogenous target proteins.

Brefeldin A↗
PubMed1993

Characterization of OM-B monoclonal antibody-defined antigen associated with mucinous type human ovarian tumor.

Partial characterization of the OM-B antigen associated with mucinous-type ovarian tumors was conducted. This antigen was defined by OM-B monoclonal antibody, which was raised against a mucinous-type ovarian tumor, and was present in all the mucinous-type tumors tested, but only a fraction of serous-type tumors. The OM-B crude antigen preparation fractionated from cystic fluids had a density of 1.40-1.43 g/ml, with a high neutral sugar content. Molecular mass (M(r)) estimated by gel filtration was more than 2,000,000. Trypsinization of the antigen preparation under appropriate conditions resulted in two major bands and one minor band with molecular sizes of less than M(r) 250,000, as detected by immunoblotting. Immunoaffinity chromatography was then conducted and the amino acid composition of the purified product was determined; the high contents of serine, threonine and proline are characteristic of a mucin. Binding inhibition enzyme-linked immunosorbent assay was developed to measure OM-B antigen activity in cystic fluids and sera from patients with mucinous-type tumors. The antigen was easily detected in most cystic fluids, but not in sera, suggesting that improvement in the sensitivity of this assay is necessary before its utilization for serum diagnosis will be feasible.

Antibodies, Monoclonal↗
PubMed1993

Taurine conjugate of ursodeoxycholate plays a major role in the hepatoprotective effect against cholestasis induced by taurochenodeoxycholate in rats.

Rats which were taurine-deprived through beta-alanine administration and untreated rats were used to elucidate the mechanism of hepatoprotective effects of ursodeoxycholate (UDC). Animals were infused with taurochenodeoxycholate (TCDC, 0.4 mumol.min-1.100 g-1) alone or in combination with tauroursodeoxycholate (TUDC), or with UDC (both 0.6 mumol.min-1.100 g-1) for 2 h. Ursodeoxycholate as well as TUDC prevented severe cholestasis and liver damage induced by TCDC infusion in both untreated and taurine-deprived rat groups. In untreated rats, however, UDC was less effective in hepatoprotection than TUDC as indicated by sequential changes in biliary LDH output during the period of 30 to 120 min (P < 0.05). In rats receiving UDC and TCDC, total biliary output of LDH for 2 h was significantly higher in taurine-deprived rats than that in the control (73.40 +/- 10.10 vs 41.14 +/- 12.56: P < 0.05), suggesting that the difference became greater upon taurine deprivation. In contrast, in rats receiving TUDC and TCDC, the protective effect was comparable for the taurine-deprived and untreated rats. When the animals were infused with UDC and TCDC, taurine-deprived rats exhibited a biliary excretion rate for TUDC half that of control rats (P < 0.05). Furthermore, a highly significant correlation was observed between the biliary excretion rate of TUDC and biliary output of LDH (r = -0.886, P < 0.0001). These results suggest that UDC conjugates, especially TUDC, and not UDC may play a major role in the prevention of cholestasis and liver cell damage caused by TCDC infusion.

Alkaline Phosphatase↗
PubMed1993

Establishment and characterization of a monoclonal antibody recognizing the Dewar isomers of (6-4)photoproducts.

We established a monoclonal antibody (DEM-1) that recognizes UV-induced DNA damage other than cyclobutane pyrimidine dimers or (6-4)photoproducts. The binding of DEM-1 antibody to 254 nm UV-irradiated DNA increased with subsequent exposure to UV wavelengths longer than 310 nm, whereas that of the 64M-2 antibody specific for the (6-4)photoproduct decreased with this treatment. Furthermore, the increase in DEM-1 binding was inhibited by the presence of the 64M-2 antibody during the exposure. We concluded that the DEM-1 antibody specifically recognized the Dewar photoproduct, which is the isomeric form of the (6-4)photoproduct. The DEM-1 antibody, however, also bound to DNA irradiated with high fluences of 254 nm UV, suggesting that 254 nm UV could induce Dewar photoproducts without subsequent exposure to longer wavelengths of UV. Furthermore, an action spectral study demonstrated that 254 nm was the most efficient wavelength for Dewar photoproduct induction in the region from 254 to 365 nm, as well as cyclobutane dimers and (6-4)photoproducts, although the action spectrum values in the UV-B region were significantly higher compared with those for cyclobutane dimer and (6-4)photoproduct induction.

Animals↗
PubMed1993

Plasmid-mediated AmpC-type beta-lactamase isolated from Klebsiella pneumoniae confers resistance to broad-spectrum beta-lactams, including moxalactam.

Klebsiella pneumoniae NU2936 was isolated from a patient and was found to produce a plasmid-encoded beta-lactamase (MOX-1) which conferred resistance to broad spectrum beta-lactams, including moxalactam, flomoxef, ceftizoxime, cefotaxime, and ceftazidime. Resistance could be transferred from K. pneumoniae NU2936 to Escherichia coli CSH2 by conjugation with a transfer frequency of 5 x 10(-7). The structural gene of MOX-1 (blaMOX-1) was cloned and expressed in E. coli HB101. The MIC of moxalactam for E. coli HB101 producing MOX-1 was > 512 micrograms/ml. The apparent molecular mass and pI of this enzyme were calculated to be 38 kDa and 8.9, respectively. Hg2+ and Cu2+ failed to block enzyme activity, and the presence of EDTA in the reaction buffer did not reduce the enzyme activity. However, clavulanate and cloxacillin, serine beta-lactamase inhibitors, inhibited the enzyme activity competitively (Kis = 5.60 and 0.35 microM, respectively). The kinetic study of MOX-1 suggested that it effectively hydrolyzed broad-spectrum beta-lactams. A hybridization study confirmed that blaMOX-1 is encoded on a large resident plasmid (pRMOX1; 180 kb) of strain NU2936. By deletion analysis, the functional region was localized within a 1.2-kb region of the plasmid. By amino acid sequencing, 18 of 33 amino acid residues at the N terminus of MOX-1 were found to be identical to those of Pseudomonas aeruginosa AmpC. These findings suggest that MOX-1 is a plasmid-mediated AmpC-type beta-lactamase that provides enteric bacteria resistance to broad-spectrum beta-lactams, including moxalactam.

Amino Acid Sequence↗
PubMed1993

Enhancement of extracapsular polysaccharide synthesis in Klebsiella pneumoniae by RmpA2, which shows homology to NtrC and FixJ.

We determined the complete nucleotide sequence of a 2.1-kb HindIII-EcoRI fragment that was cloned from a resident large plasmid of Klebsiella pneumoniae Chedid, a highly virulent and mucoviscous strain of the O1:K2 serotype. This fragment encoded an ability to enhance K2 capsular polysaccharide synthesis in K. pneumoniae, and a 636-bp open reading frame (rmpA2) was found. The 411-bp rmpA reported to be involved in the virulence and mucoid phenotypes of K. pneumoniae by Nassif et al. (Mol. Microbiol. 3:1349-1359, 1989) was a part of rmpA2. Eighty percent homology in nucleotide sequence was found between rmpA2 and rmpA in the corresponding regions. The central domain of the deduced amino acid sequence of RmpA2 showed considerable homology to the central domains of NtrC of K. pneumoniae and Escherichia coli, to which the sigma factor of RNA polymerase binds. The C-terminal domain of RmpA2 also demonstrated considerable homology with the putative helix-turn-helix motifs of LuxR of Vibrio fischeri and FixJ of Rhizobium meliloti. Moreover, RmpA2 also showed some homology in its N- and C-terminal regions to those of RcsA, a transcriptional activator for colanic acid synthesis in E. coli. On the other hand, a sequence upstream of rmpA2 was found to be highly homologous to insertion sequence 3 of members of the family Enterobacteriaceae. Southern hybridization analysis suggested that rmpA2 exists on the large plasmids of all mucoviscous virulent K2 strains but not on those of the slightly mucoviscous avirulent strains. Freeze substitution electron microscopy and fluorescent-antibody staining with anti-K2 serum revealed that K. pneumoniae Chedid has a dense and thick capsule (180 nm) with dense extracapsular substance, whereas K. pneumoniae K2-215, one of the slightly mucoviscous and avirulent strains, has a capsule which is looser and thinner (120 nm) than that of strain Chedid and no extracapsular substance. Introduction of rmpA2 into K2-215 as well as reference strains K. pneumoniae K9 and K72 resulted in a change of the colony phenotype to highly mucoviscous through abundant production of extracapsular substance which reacted with anti-K2, -K9, or -K72, respectively, as did their parental strains. From these results, it is suggested that RmpA2 belongs to the family of transcriptional regulators and confers a highly mucoviscous phenotype on cells of various serotypes of K. pneumoniae by enhancing extracapsular polysaccharide synthesis.

Amino Acid Sequence↗
PubMed1993

Adaptive changes in zonation for gluconeogenic capacity in liver lobules of cold-exposed rats.

The rate of gluconeogenesis from lactate increased in perfused livers after exposure of rats to cold for 5 days, and it returned to the control rate after 20 days [M. Shiota, T. Tanaka, and T. Sugano. Am. J. Physiol. 249 (Endocrinol. Metab. 12): E281-E286, 1985.]. The relationship between the increased gluconeogenic activity and its zonal distribution in liver lobules was studied in cold-exposed rats that had been starved for 24 h by examination of preparations enriched for periportal hepatocytes (PP-H) and for perivenous hepatocytes (PV-H), which had been isolated by the digitonin-collagenase perfusion technique. In the control group, the rate of gluconeogenesis from lactate or alanine was three times higher in PP-H than in PV-H. The rate of gluconeogenesis from these substrates in PP-H was not changed by exposure of rats to cold. The rates of PV-H increased to the level in PP-H after 5 days of exposure of rats to cold and then returned to the control rates after 20 days. The rate of gluconeogenesis from fructose was not altered in either preparation of cells by cold treatment of rats. The change in gluconeogenic capacity in PV-H caused by exposure of rats to cold was unrelated to changes in the activity of the malate-aspartate shuttle and of pyruvate kinase. The increased capacity in mitochondrial respiration was observed in both preparations of cells by cold treatment of rats for 5 days. The activity of phosphoenolpyruvate carboxykinase was higher in PP-H than in PV-H in the control group.(ABSTRACT TRUNCATED AT 250 WORDS)

Adaptation, Physiological↗
PubMed1993

Responses to catecholamines in perfused livers of hypothalamic-lesioned rats.

The responses of hepatic glycogenolysis to catecholamines in ventromedial hypothalamus (VMH)-lesioned male rats were examined in perfused livers. Seven days after bilateral electrical lesioning of the VMH, the livers were perfused. Isoproterenol, a beta-agonist, stimulated greater glucose production in VMH-lesioned rats than in controls (32.8 vs. 5.6 mumol glucose.h-1.g liver-1), while responses to phenylephrine, an alpha-agonist, decreased significantly compared with controls (44.4 vs. 69.8 mumol glucose.h-1.g liver-1). There were no significant differences in responses of livers to glucagon and vasopressin between control and VMH-lesioned rats. Adrenodemedullation showed the same effect on beta-responses as lesions in the VMH, but no effect on alpha-responses. Plasma epinephrine levels were not detectable with the high-performance liquid chromatography analysis in VMH-lesioned rats. The periodicity of plasma corticosterone levels was observed in both VMH-lesioned and control rats, although daytime increases in plasma corticosterone were blocked by VMH lesions. These results suggest that the lesions in the VMH cause changes in the levels of adrenergic receptor and that the increase in beta-responses is caused mostly by the reduction of plasma epinephrine.

Adrenalectomy↗
PubMed1993

Effects of acute hypotensive hemorrhage on arginine vasopressin gene transcription in the rat brain.

To determine whether hypotensive hemorrhage has an effect on arginine vasopressin (AVP) gene expression, 16 ml/kg of arterial blood was drawn over 10 min in conscious unrestrained rats. Mean arterial blood pressure (MABP) and heart rate (HR) were measured, and the rats were decapitated before and 10 min, 1, 3, 6, 9, 12, and 24 h after the initiation of hemorrhage. The hypothalamic or cerebro-hypothalamic tissue was used to measure AVP mRNA by Northern blot analysis, and the trunk blood to measure plasma AVP, osmolality and hematocrit. Hemorrhage brought about rapid and transient decreases in MABP and HR accompanied by transient increases in plasma osmolality and AVP. Hematocrit decreased after the bleeding and reached a stable level 6 h after hemorrhage and thereafter. AVP mRNA was detected in the hypothalamus and not in the extrahypothalamic cerebral brain tissue under basal and posthemorrhage conditions. AVP mRNA in the cerebro-hypothalamic tissue increased by 1.8-fold at 6 h and 2.1-fold at 9 h after hemorrhage. These results indicate that AVP mRNA in the brain increases 6 h after increased AVP release in response to hypotensive hemorrhage.

Acute Disease↗
PubMed1993

[Dietary fiber intake and intake patterns among the general population in Aomori, calculated using modified Southgate and Prosky methods].

Based on the result of the Aomori Nutrition Survey, we have calculated daily dietary fiber (DF) intake using modified Southgate and Prosky methods. Result obtained were as follows: DF intake in Aomori was 23.7 +/- 8.4g by the modified Southgate method, and 22.2 +/- 8.5g by the modified Prosky method. As for supply sources of DF, 32.3% was from grains; 22.7%, vegetables; 15.6%, beans; and 7.8%, fruits calculated by the modified Southgate method, and 31.3%, vegetables; 19.0%, grains; 18.0%, beans; and 11.6%, fruits by the modified Prosky method. As to types of DF, intake of hemicellulose was 11.5 +/- 4.2g, cellulose 7.8 +/- 3.0g and lignin 4.4 +/- 2.3g. In the group with DF intake below 10.0g, DF came mainly from grains and fruits, while the group with DF intake above 30.0g took DF from various foods.

Adolescent↗
PubMed1993

Role of vagal nerves and atrial natriuretic hormone in vasopressin release and a diuresis under hypertonic volume expansion.

To assess whether increases in circulating atrial natriuretic hormone (ANH) in response to the plasma volume expansion, besides the volume receptor-mediated mechanisms, attenuate the arginine vasopressin (AVP) response to increased plasma osmolality and whether changes in plasma AVP and ANH affect renal solute excretion under hypertonic plasma volume expansion, hypertonic saline (0.95 mol/l saline) alone, hypertonic saline with 6% dextran (6D-HS) and hypertonic saline with 9% dextran (9D-HS) were administered into anesthetized dogs. In the control study, 0.15 mol/l NaCl alone was administered. Plasma AVP and ANH and cardiovascular and renal functions were determined. Hypertonic saline and 9D-HS also were administered into the vagotomized and sham operated dogs, and the same parameters were determined. Mean blood pressure and heart rate never changed in all the groups, but central venous pressure and plasma volume increased markedly in 6D-HS and 9D-HS groups. In the control and hypertonic saline groups, central venous pressure increased slightly but plasma volume never changed. Plasma AVP increased in the order of hypertonic saline, 6D-HS and 9D-HS, but plasma ANH increased in reverse order. Vagotomy restored the AVP response to 9D-HS to 75% of its response to hypertonic saline, with a marked rise in plasma ANH. Urine sodium and potassium excretion and urine flow increased in hypertonic saline, 6D-HS and 9D-HS groups, but these increases were comparable among the groups. In the control group, these parameters never changed. These results suggest that the volume receptor-mediated vagal neural and ANH responses to the plasma volume expansion may have an effect on the suppression of the AVP response to osmotic stimuli, and increased plasma ANH release never potentiated the natriuresis under the hypertonic plasma volume expansion.

Animals↗
PubMed1993

Sclerosing peritonitis associated with keratoconjunctivitis sicca, pleurisy, and secretory otitis media.

A male case of sclerosing peritonitis of unknown cause, associated with keratoconjunctivitis sicca, pleurisy, and secretory otitis media, is presented. These unusual complications are very similar to the adverse reactions to the beta-adrenergic blocking agent, practolol, which is known to cause sclerosing peritonitis. This similarity suggests an etiological association between the sclerosing peritonitis of this case and that caused by practolol. The sclerosing peritonitis of this case may be considered to occur as part of some systemic disorder, and thus casts doubt on the hitherto accepted hypothesis that sclerosing peritonitis results from infectious peritonitis.

Humans↗
PubMed1993

Experimental murine model for autoimmune myocarditis using Klebsiella pneumoniae O3 lipopolysaccharide as a potent immunological adjuvant.

Experimental autoimmune myocarditis could be produced in mice by repeated injection of syngeneic heart extract together with Klebsiella pneumoniae O3 lipopolysaccharide (KO3 LPS) as a powerful adjuvant. Histological changes in the cardiac lesions were characterized by infiltration with mononuclear cells in the myocardium, degeneration and loss of myocardial fibers, and replacement of granulation tissues. No such cardiac lesions were produced in mice receiving injections of heart extract alone or KO3 LPS alone. Development of the autoantibody and the delayed type-hypersensitivity (DTH) against syngeneic heart extract was found in mice immunized repeatedly with the mixture of heart extract and KO3 LPS. Moreover, definite cardiac lesions were produced in normal recipient mice by transfer of sensitized spleen cells from hyperimmunized mice. Therefore, it was suggested that those cardiac lesions were caused by the autoimmune mechanism. Our methodology provided a new experimental murine model for autoimmune myocarditis.

Adjuvants, Immunologic↗
PubMed1993

Research note: effect of tu-chung leaf (Eucommia ulmoides) on egg production performance, egg quality, and fat metabolism in laying hens at a late production stage.

The effects of tu-chung leaf (Eucommia ulmoides) supplementation on egg production performance, egg quality, and fat metabolism were investigated in laying hens at a late production stage. White Leghorn laying hens at 20 mo of age were provided ad libitum access to a practical diet with or without tu-chung leaf supplement for 3 mo. During the experimental period, egg production rate, egg weight, and feed intake were recorded every day. Egg samples from the last 3 days were collected to measure Haugh units and cholesterol concentration in the egg yolk. Plasma cholesterol concentration and abdominal fat weight were also determined. The results showed that no significant improvement in egg production was observed with tu-chung leaf addition. No significant effect of tu-chung was observed on Haugh units, plasma cholesterol, or egg yolk cholesterol, whereas abdominal fat weight was greater in hens fed the tu-chung diet than in those given the unsupplemented control diet. It was concluded that the beneficial effects of tu-chung leaf supplementation on egg production performance and egg quality were ambiguous and of little practical significance.

Animals↗
PubMed1993

[Studies on the quality of enzyme preparations (XII)--lysozyme preparations].

This paper was described the results of the weight variation test and the assay for the potency of the commercially available lysozyme preparations (samples: 13 kinds of granules, in which 10 kinds are granules (folded)) collected for the legal sampling inspection in 1992. The potencies of 10 samples were found to be within the range of permissible content, when the all samples extracted with phosphate buffer were determined by the method described in Japanese Standards of Pharmaceutical Ingredients. However, the potencies of 3 samples were not more than 65% of the labeled potencies. These low potency samples showed the potencies of 98-106%, when 0.4M sodium chloride solution or 0.1N hydrochloric acid was used instead of phosphate buffer for enzyme extraction. The weight variation test showed all preparations to be within the permissible JP XII deviation range (10%) for "granules (folded)".

Dosage Forms↗