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Biomedical subjects

M Ohno

Publications and source records attributed to M Ohno.

At least 271 records · Page 15Linked to original sources
PubMed1994

Intrahippocampal administration of the NO synthase inhibitor L-NAME prevents working memory deficits in rats exposed to transient cerebral ischemia.

A 5-min period of cerebral ischemia increased the number of errors in a working memory task with three-panel runway paradigm, while it had no effect on reference memory errors. The nitric oxide (NO) synthase inhibitor, NG-nitro-L-arginine methyl ester (L-NAME), infused into the bilateral dorsal hippocampus at 100 micrograms/side immediately after blood flow reperfusion, significantly reduced the increase in working memory errors expected to occur 24 h after 5 min of ischemia. Intrahippocampal administration of the inactive isomer D-NAME at 100 micrograms/side immediately after reperfusion had no effect on the increase in working memory errors in the ischemic rats. These findings suggest that the mechanism mediated by hippocampal NO synthesis during the early reperfusion phase contributes to the postischemic impairment of working memory.

Amino Acid Oxidoreductases↗
PubMed1994

Effect of cadmium (CdCl2) on cell proliferation and production of EDRF (endothelium-derived relaxing factor) by cultured human umbilical arterial endothelial cells.

The effect of cadmium chloride (CdCl2) on cell proliferation and EDRF (endothelium-derived relaxing factor) production by cultured human umbilical arterial endothelial cells (HUAECs) was investigated. The viability of HUAECs decreased dose-dependently after the addition of Cd (cadmium chloride). Morphologic examination by phase contrast microscopy revealed severe damaging effects of Cd at higher concentrations. The cytotoxic effect of Cd on DNA synthesis was also concentration-dependent. The effect of Cd on EDRF production by indomethacin-treated HUAECs was assessed by its anti-platelet aggregatory effect. Platelet aggregation studies were carried out in cuvettes lined with HUAECs using an aggregometer. The anti-platelet aggregatory effect was decreased dose-dependently by pretreatment with Cd. These findings suggest that HUAECs are susceptible to concentration-dependent Cd cytotoxicity, and that Cd can inhibit the production of EDRF by HUAECs.

Cadmium↗
PubMed1994

Purification and characterization of a coagulant enzyme, okinaxobin II, from Trimeresurus okinavensis (himehabu snake) venom which release fibrinopeptides A and B.

A coagulant enzyme, okinaxobin I, which was purified from Trimeresurus okinavenis (himehabu snake) venom, released specifically fibrinopeptide B from fibrinogen to form fibrin clots. In the present study, its isozyme denoted as okinaxobin II has been purified to homogeneity from the same venom by chromatographies on Sephadex G-100, CM-Toyopearl 650M, and FPLC Mono-Q columns. Differently from okinaxobin I, okinaxobin II specifically cleaved fibrinopeptides A and B from fibrinogen similarly as found for alpha-thrombin. The enzyme acted on fibrinogen with specific activity of 42 NIH units/mg at optimum pH of 8.0. Okinaxobin II was a monomeric glycoprotein with a mol. wt of 37,500 on SDS-PAGE, which was reduced to 29,500 after treatment with N-glycanase. Okinaxobin II was much more basic (pI = 8.1) than okinaxobin I (pI = 5.4). The N-terminal sequence was highly similar to those of okinaxobin I and some other snake venom coagulant enzymes such as flavoxobin (Trimeresurus flavoviridis), batroxobin (Bothrops atrox and Bothrops moojeni), and catroxobin (Crotalus atrox). Okinaxobin II hydrolyzed tosyl-L-arginine methyl ester and benzoyl-L-arginine p-nitroanilide. The esterase activity was strongly inhibited by diisopropylfluorophosphate and to a lesser extent by tosyl-L-lysine chloromethyl ketone, indicating that the enzyme is a serine protease like alpha-thrombin. In terms of amino acid composition, okinaxobin II was similar to okinaxobin I and dissimilar to alpha-thrombin.

Amino Acid Sequence↗
PubMed1994

The DNA diagnosis for bulbospinal muscular atrophy.

We showed the analysis of the androgen receptor gene in 6 patients with bulbospinal muscular atrophy (BSMA). Four of them had typical manifestations of Kennedy's disease, while the other 2 patients did not show androgen insensitive signs such as gynecomastia or testicular atrophy. Enlarged CAG repeats were found in 4 patients with typical Kennedy's disease and 1 patient without androgen insensitive signs. This fact suggests that the DNA diagnosis by analysis of the androgen receptor gene is very useful to distinguish Kennedy's disease from other forms of BSMA.

DNA↗
PubMed1994

Comparison of the binding of beta-cyclodextrin and alpha- and gamma-cyclodextrins with pullulanase from Klebsiella pneumoniae as studied by equilibrium and kinetic fluorometry.

The change in fluorescence spectra of crystalline pullulanase from Klebsiella pneumoniae caused by the addition of alpha-, beta-, and gamma-cyclodextrins and 6-O-alpha-glucosyl-alpha-cyclodextrin and 6-O-alpha-glucosyl-beta-cyclodextrin was investigated at 25 degrees C and pH 5.6. The fluorescence intensity at around 325 nm (excitation at 280 nm) was increased by the addition of all the cyclodextrins studied. The dissociation constant, Kd, of the enzyme-cyclodextrin complex was evaluated by fluorometric titration for each cyclodextrin, and was consistent with the inhibitor constant, Ki, obtained previously [Iwamoto et al. (1993) J. Biochem. 113, 93-96]. The Kd values of beta-cyclodextrin and 6-O-alpha-glucosyl-beta-cyclodextrin were approximately two orders of magnitude smaller than those of alpha- and gamma-cyclodextrins. Fluorescence titration of a cyclodextrin in the presence of another cyclodextrin revealed competition among alpha-, beta-, and gamma-cyclodextrins for binding with the enzyme, which indicates that the binding region of beta-cyclodextrin overlaps those of alpha- and gamma-cyclodextrins. On the other hand, with excitation at 295 nm, a fluorescence spectral change similar to that excited at 280 nm was observed for alpha- and gamma-cyclodextrins and 6-O-alpha-glucosyl-alpha-cyclodextrin, whereas beta-cyclodextrin and 6-O-alpha-glucosyl-beta-cyclodextrin did not show any such change. These results suggest that the binding site or the binding mode of beta-cyclodextrin is slightly different from those of alpha- and gamma-cyclodextrins.(ABSTRACT TRUNCATED AT 250 WORDS)

Bacterial Proteins↗
PubMed1994

Noninvasive, continuous blood pressure measurement by arterial tonometry during anesthesia in children.

BACKGROUND: The authors' previous study of arterial tonometry in children demonstrated poor agreement of tonometric blood pressure (TBP) measurements with intraarterial blood pressure (IBP) measurements. The aim of the current study is to evaluate the feasibility of TBP measurements in children aged 1-6 yr using a newly designed pediatric sensor housing, by comparing TBP values with values obtained by IBP measurements. METHODS: Thirty-four children (aged 1-6 yr, ASA physical status 1-2) were studied undergoing elective abdominal or urologic surgery under general anesthesia. A 22- or 24-G cannula was inserted into the right radial artery. A TBP sensor housing was positioned over the left radial artery. TBP and IBP were continuously monitored and data were periodically sampled during and after intubation, during surgery, and during the recovery period. RESULTS: TBP waveforms were similar to those of IBP. Limits of agreement (bias +/- 2 SD) were 12 and -13.3 mmHg for systolic, 11.6 and -10.4 mmHg for mean, and 13.2 and -10.8 mmHg for diastolic pressures for 3,400 paired points. Measurements could not be made in ten children because of insufficient pulse contour. CONCLUSIONS: When pulse contour is sufficient for analysis, TBP monitoring provides an apparently safe and accurate method for the continuous measurement of arterial blood pressure during anesthesia in children aged 1-6 yr.

Anesthesia↗
PubMed1994

Gene expression for tumor necrosis factor alpha and its production in gastric cancer patients.

To determine the gene expression for tumor necrosis factor (TNF) alpha and its main site of production in gastric cancer patients, serum levels in the peripheral venous blood of 50 patients and the portal blood from 15 of these 50 patients were measured by enzyme-linked immunosorbent assay (ELISA). TNF gene expression in the peripheral blood mononuclear cells (PBMC) and in the surgically resected tissues was then studied in 16 patients by reverse transcription-polymerase chain reaction (RT-PCR) assay. Whereas TNF mRNA expression was detected in the PBMC from 13 of 16 gastric cancer patients (81.3%), it was detected in only one tumor tissue (6.3%). Preoperatively, TNF was detected in the serum from 13 of 50 patients (26.0%). In the portal blood sampled immediately after laparotomy, TNF was positive in 4 of 15 patients (26.7%). TNF gene expression was much more frequently detected in PBMC than in other resected tissues, and its expression was higher than in the serum. Various clinicopathological factors for gastric cancer were not related to the preoperative detection of TNF in the serum. It appears that TNF is produced mainly in PBMC but not in the cancer regions or the regional lymph nodes of gastric cancer patients. It is suggested that TNF is not always secreted even when TNF mRNA is expressed, and its preoperative production is not related to tumor progression.

Base Sequence↗
PubMed1994

Identification of a putative RNA helicase (HRH1), a human homolog of yeast Prp22.

In the budding yeast Saccharomyces cerevisiae, a number of PRP genes known to be involved in pre-mRNA processing have been genetically identified and cloned. Three PRP genes (PRP2, PRP16, and PRP22) were shown to encode putative RNA helicases of the family of proteins with DEAH boxes. However, any such splicing factor containing the helicase motifs in vertebrates has not been identified. To identify human homologs of this family, we designed PCR primers corresponding to the highly conserved region of the DEAH box protein family and successfully amplified five cDNA fragments, using HeLa poly(A)+ RNA as a substrate. One fragment, designated HRH1 (human RNA helicase 1), is highly homologous to Prp22, which was previously shown to be involved in the release of spliced mRNAs from the spliceosomes. Expression of HRH1 in a S. cerevisiae prp22 mutant can partially rescue its temperature-sensitive phenotype. These results strongly suggest that HRH1 is a functional human homolog of the yeast Prp22 protein. Interestingly, HRH1 but not Prp22 contains an arginine- and serine-rich domain (RS domain) which is characteristic of some splicing factors, such as members of the SR protein family. We could show that HRH1 can interact in vitro and in the yeast two-hybrid system with members of the SR protein family through its RS domain. We speculate that HRH1 might be targeted to the spliceosome through this interaction.

Amino Acid Sequence↗
PubMed1994

Mechanism of altered patterns of left ventricular filling during the development of congestive heart failure.

BACKGROUND: The mechanism of the alterations in the pattern of left ventricular (LV) filling during the development of congestive heart failure (CHF) is not fully understood. METHODS AND RESULTS: We studied six conscious dogs instrumented to measure LV and left atrial (LA) pressures and LV volume as CHF was induced by rapid pacing. Diastolic filling dynamics were serially measured over 4 weeks during normal sinus rhythm. Four days after we initiated pacing, the peak early diastolic filing rate decreased from 108 +/- 24 to 88 +/- 27 mL/s (P < .05) as the maximal early diastolic LA-LV pressure gradient decreased associated with a slowing of the rate of LV relaxation. Subsequently, the peak early filling rate progressively increased, returning to control at 1 week, and by the fourth week, it had increased to 168 +/- 39 mL/s (P < .05). These changes in early filling rates occurred as the maximal early diastolic LA-LV pressure gradient increased in association with a progressive increase in LV pressure despite further progressive slowing of the rate of LV relaxation. Throughout the development of CHF, peak early filling rate and the maximal LA-LV pressure gradient correlated (r = .99, P < .001). The early filling deceleration rate increased and deceleration time progressively decreased over the 4 weeks as LV stiffness and net LA plus LV stiffness increased (P < .05). As predicted by a theoretical analysis, the deceleration time was linearly related to the reciprocal of the square root of LV stiffness (r = .94, P < .01). CONCLUSIONS: Early in CHF, slowing of LV relaxation reduces the maximal early diastolic LA-LV pressure gradient, decreasing the peak early filling rate. As CHF progresses, this is overcome by an increase in LA pressure that augments the early diastolic LA-LV pressure gradient, increasing peak early filling rate. Increasing LV stiffness during the development of CHF progressively shortens the early filling deceleration time and augments the early filling deceleration rate. These observations suggest that the early filling deceleration time reflects LV stiffness.

Animals↗
PubMed1994

[The active conformation of teleocidins: design and synthesis of new active molecules].

This review deals with structure-activity relationships, conformational analysis of teleocidins and creation of new active compounds for the determination of active conformation of teleocidins. Phorbol esters containing 12-O-tetradecanoylphorbol-13-acetate (TPA) and teleocidins which are classified as TPA-type tumor promoters exhibit potent tumor-promoting activity as well as many important biological activities connected with cell prolification and cell differentiation. Teleocidins are known to exist in an equilibrium between two conformational states in solution, the twist and the sofa forms. The low energy barrier between the two conformers makes it difficult to identify the mode of interaction of these promoters with common macromolecular targets. Design and synthesis of molecules having a new skeleton (benzolactams) and producing two conformations of teleocidins solve the problem. Benzolactams become the simplest molecule reproducing the conformation and activity of teleocidin, and will be a useful tool for the study of tumor-promotion and cell differentiation.

Animals↗
PubMed1994

Exercise-induced ST-segment elevation and hemodynamic responses one month after myocardial infarction.

Changes in hemodynamics and plasma norepinephrine levels during supine bicycle exercise after myocardial infarction were measured to investigate the mechanism of exercise-induced ST-segment elevation. Seventy-eight patients were divided into groups which showed either ST elevation (STE), ST depression (STD), or no ST changes (STU). Most of the STE group had anterior myocardial infarction (90.6%) and single-vessel disease (76.7%). The STE group achieved a significantly higher workload (119.5 +/- 4.0 watts, mean +/- SEM) than the STD group (82.3 +/- 2.8, p < 0.01). Heart rate and cardiac output at maximal workload were significantly higher in the STE group (136.6 +/- 3.4 beats/min, 7.44 +/- 0.28 l/min/m2) than in the STD group (110.0 +/- 3.9, 4.83 +/- 0.36, p < 0.01). Pulmonary artery pressures were less elevated in STE than STD patients. Plasma norepinephrine levels increased significantly at maximal workload in STE patients, as compared to the other groups. In conclusion, the STE group achieved a higher exercise level associated with augmented sympathetic activity, which may be a possible mechanism of exercise-induced ST elevation after myocardial infarction.

Cardiac Output↗
PubMed1994

Polymorphisms of Trimeresurus flavoviridis venom gland phospholipase A2 isozyme genes.

Trimeresurus flavoviridis venom gland phospholipase A2 (PLA2) genes pgPLA 1a and pgPLA 2a encode Asp-49-PLA2 and genes pgPLA 1b and pgPLA 2b encode an isozyme of Asp-49-PLA2. Polymorphisms were found in pairs of pgPLA 1a and pgPLA 2a and of pgPLA 1b and pgPLA 2b for individuals of T. flavoviridis. The occurrence of both homozygotes and heterozygotes was demonstrated.

Animals↗
PubMed1994

Metabolism and pharmacokinetics of dihydrocodeine in dog.

1. The metabolism and pharmacokinetics of dihydrocodeine have been studied in dog. Urinary metabolites after oral administration of dihydrocodeine were identified using hplc with diode-array and ms. 2. In urine, dihydronorcodeine, dihydromorphine and dihydrocodeine glucuronide were identified in comparison with their authentic standards, and dihydronorcodeine 6-glucuronide also appeared to be excreted as a metabolite. 3. The major urinary metabolite was dihydrocodeine glucuronide, recovered as 49% of the dose, and other metabolites were found to be 0.1-3%, 24 h after 3 mg/kg oral administration of dihydrocodeine. Plasma concentrations of unchanged dihydrocodeine were significantly lower after oral rather than intramuscular administration; the maximum concentrations were 40 and 549 ng/ml after oral and intramuscular administration, respectively. This suggests that dihydrocodeine was metabolized via a hepatic first-pass effect after oral administration. 4. Overall, our results indicate that the metabolic pathways of dihydrocodeine in dog were similar to that of codeine metabolism in animals and man.

Administration, Oral↗
PubMed1994

[Identification of Mycobacterium avium and Mycobacterium intracellulare using DNA probe test, and their ratio in Niigata area].

Using Gen-Probe test, both the Mycobacterium avium and Mycobacterium intracellulare strains were identified in the 76 disease-associated Mycobacterium-avium complex (MAC) strains isolated in the NIIGATA area. The following results were obtained: 1) Fifty-four MAC strains (71.1%) reacted with M. avium-probe and 22 strains (28.9%) reacted with M. intracellulare-probe. 2) There were no significant differences between the ratio of two strains before and after 1991. 3) The ratio of female cases with M. avium was significantly higher (22/32) in the later period (after 1991) than in the former period (9/22).

DNA Probes↗