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Biomedical subjects

M Ohmura

Publications and source records attributed to M Ohmura.

At least 19 recordsLinked to original sources
PubMed1992

Investigation of the external aperture of the vestibular aqueduct in Menière's disease by three-dimensional image analysis.

The width of the external aperture of the vestibular aqueduct was measured in patients with Meniere's disease using three-dimensional images. The width of the aperture on the affected side was significantly smaller compared with that in normal ears or ears with chronic otitis media. Also, the width of the aperture on the opposite (healthy) side in unilateral Meniere's disease was significantly smaller than in these two other groups. These findings suggest that the aqueduct is incompletely developed in patients with Meniere's disease and that this may be related to the pathogenesis of this condition. Also, in unilateral Meniere's disease the opposite ear runs a high risk of eventually developing the disease.

Adolescent↗
PubMed1992

[Screening for ovarian cancer].

In recent years, ovarian cancer has been increasing in Japan. However, a mass-screening system for ovarian cancer is not yet established. For this reason, detection of early ovarian cancer is very difficult. 1. Due to the low frequency of ovarian cancer detection, a mass-screening system is not cost-effective. 2. There is no accurate method for the detection of ovarian cancer, as with cytology or colposcopy for the detection of uterine cancer. We describe some methods for the detection of ovarian cancer by mass screening, and point out some problems. Tumor marker is not always useful because of its low sensitivity for early ovarian cancer. It is most important to determine whether or not an ovarian tumor is present. We attempted to detect ovarian tumors at the time of uterine cancer mass screening by ultrasonography (transvaginal proof). Three early ovarian cancers were detected in 10,294 women.

Adult↗
PubMed1991

Kinetic and stereochemical characterization of hamster liver 3 alpha-hydroxysteroid dehydrogenase and 3 alpha(17 beta)-hydroxysteroid dehydrogenase.

The kinetic mechanism of NADP(+)-dependent 3 alpha-hydroxysteroid dehydrogenase and NAD(+)-dependent 3 alpha(17 beta)-hydroxysteroid dehydrogenase, purified from hamster liver cytosol, was studied in both directions. For 3 alpha-hydroxysteroid dehydrogenase, the initial velocity and product inhibition studies indicated that the enzyme reaction sequence is ordered with NADP+ binding to the free enzyme and NADPH being the last product to be released. Inhibition patterns by Cibacron blue and hexestrol, and binding studies of coenzyme and substrate are also consistent with an ordered bi bi mechanism. For 3 alpha(17 beta)-hydroxysteroid dehydrogenase, the steady-state kinetic measurements and substrate binding studies suggest a random binding pattern of the substrates and an ordered release of product; NADH is released last. However, the two enzymes transferred the pro-R-hydrogen atom of NAD(P)H to the carbonyl substrate.

17-Hydroxysteroid Dehydrogenases↗
PubMed1991

Observation of the external aperture of the vestibular aqueduct using three-dimensional surface reconstruction imaging.

Observation of the external aperture of the vestibular aqueduct was hitherto possible only in cadavers or dry temporal bones; however, by applying three-dimensional surface reconstruction imaging, it is now possible to observe solid-looking images of this structure in living humans. When the width of the external aperture of the vestibular aqueduct was measured in 58 people, it was found to be significantly narrower in the affected ears of patients with Meniere's disease than in normal ears.

Chronic Disease↗
PubMed1991

Comparative studies on distribution and fine morphology of the intestinal Peyer's patches in Mongolian gerbils (Meriones unguiculatus) and mice.

The intestinal Peyer's patches (PP) were significantly different in distribution and fine morphology between Mongolian gerbils and mice. The PP of gerbils were evenly distributed from the duodenum to ileum, whereas the PP of mice were more densely distributed in the lower ileum than other parts of the intestine. In gerbils, each PP had a much greater number of lymphoid follicles than in mice, although the total number of PP was smaller. Electron microscopy revealed that the PP dome of gerbils was covered with two types of epithelial cells, one with shorter microvilli and the other with longer ones, whereas the epithelial cells of the murine PP dome was uniform-shaped with numerous medium-sized microvilli. Some dome absorptive cells of gerbils were morphologically similar to poorly differentiated crypt cells of mice, suggesting to be immature M cells.

Animals↗
PubMed1990

Demonstration of 3 alpha(17 beta)-hydroxysteroid dehydrogenase distinct from 3 alpha-hydroxysteroid dehydrogenase in hamster liver.

NAD(+)-linked and NADP(+)-linked 3 alpha-hydroxysteroid dehydrogenases were purified to homogeneity from hamster liver cytosol. The two monomeric enzymes, although having similar molecular masses of 38,000, differed from each other in pI values, activation energy and heat stability. The two proteins also gave different fragmentation patterns by gel electrophoresis after digestion with protease. The NADP(+)-linked enzyme catalysed the oxidoreduction of various 3 alpha-hydroxysteroids, whereas the NAD(+)-linked enzyme oxidized the 3 alpha-hydroxy group of pregnanes and some bile acids, and the 17 beta-hydroxy group of testosterone and androstanes. The thermal stabilities of the 3 alpha- and 17 beta-hydroxysteroid dehydrogenase activities of the NAD(+)-linked enzyme were identical, and the two enzyme activities were inhibited by mixing 17 beta- and 3 alpha-hydroxysteroid substrates, respectively. Medroxyprogesterone acetate, hexoestrol and 3 beta-hydroxysteroids competitively inhibited 3 alpha- and 17 beta-hydroxysteroid dehydrogenase activities of the enzyme. These results show that hamster liver contains a 3 alpha(17 beta)-hydroxysteroid dehydrogenase structurally and functionally distinct from 3 alpha-hydroxysteroid dehydrogenase.

17-Hydroxysteroid Dehydrogenases↗
PubMed1990

Differences in endocochlear potentials in response to anoxia in maturing and mature guinea pigs.

Endocochlear potential (EP) responses to anoxia in immature and mature guinea pigs were compared. The EP decreased much more slowly after anoxia in guinea-pig embryos than in neonates. In many of the embryos, the EP failed to reach any negative voltage. These findings show that the development of the negative component of the EP is a function of the maturation of its positive component.

Action Potentials↗
PubMed1990

[Analysis of scintigrams using fuzzy theory].

Textural features for phantom images were extracted. Texture parameters which represent RI distribution--skew, energy, entropy and angular second moment were used. But, it was difficult to analyse the images using discriminant analysis for textural features, because textural features had statistical noise. Therefore fuzzy reasoning was adapted to analyse the images. Textural features for six kinds of images were showed using membership function. The possibility to the image was evaluated using the value of membership function on each images. Fuzzy reasoning could be done easily using max-min composition formula. The reasoning was found more suitable to analyse the images than discriminant analysis and will be considered useful for analysis of clinical scintigrams.

Algorithms↗
PubMed1990

[Report of a case--adenoma of the middle ear].

A 44-year-old female with adenoma of the middle ear was reported. Her chief complaint was hearing loss in the right ear. A white mass inside the right external auditory canal was observed. Audiometry revealed a combined deafness with the average hearing of 38.3 dB for the speech frequencies. The study by high resolution X-ray CT revealed a density area as like as a soft mass in the tympanic cavity. A tumor existing mainly in the hypotympanum was surgically removed and modified type III tympanoplasty by interposing the malleus head as an autograft as a columella was done. Postoperative course was good and the average hearing improved slightly to 30 dB. Histopathological study with stains of HE, PAS, mucicarmin, colloid iron, NSE and S-100 protein showed adenoma of the middle ear.

Adenoma↗
PubMed1990

[A simple method of extracorporeal membrane oxygenation (ECMO)--3. The effects of pumpless ECMO (arterio-venous shunt) on arterial blood gas measured for 24 hours].

In eight anesthetized mongrel dogs, the pumpless ECMO applied between the femoral artery and vein was performed under the condition of hypoventilation for 24 hours. The methods were same as the first and second reports, except the pumpless ECMO was used. The abnormal parameters in the cardiovascular and respiratory system (blood gas analysis and end expiratory gas analysis), induced by hypoventilation, recovered to almost normal ranges, by operation of the pumpless ECMO for 24 hours. The pumpless ECMO might have such advantages over ECMO with pump as the less destruction of blood cell, easy performance and simple apparatus. In conclusion, pumpless ECMO using arterio-venous shunt may be applied clinically on respiratory distress conditions.

Animals↗
PubMed1990

[A behavioral dental science research concerning prevention of dental fear. A report on the surveys of dental fear in four countries Japan, Indonesia, Brazil and Argentina].

We conducted a behavioral scientific research from the point of view of dental fear prevention. This time, the writers carried out the surveys with the goal of understanding and making clear the realities concerning dental anxiety in the four countries: Japan, Indonesia, Brazil and Argentina. The subjects were 728 dental students from the four countries, and the surveys consisted of 25 multiple choice questions which were divided into three major areas. The first area consisted of preliminary questions such as chief complaints and treatment experiences, the second area dealt with the reactions and physical responses on receiving dental treatment and the third area was on the different levels of anxiety shown during treatment expressed through feelings and reactions. We concluded as follows: 1. In Japan, 77% of the subjects reported having at least a little fear and this percentage was higher than those of other countries (45-65%). But in all countries, 4-7% of subjects reported having extreme dental fear. 2. In Japan and Brazil, women reported the higher fear than men. In Indonesia and Argentina, these results were the opposite. 3. According to canonical correlation analysis, a significant correlation between the level of physical reactions and the degree of dental anxiety was found in all countries. 4. In the high fear group, dental anxiety increased by psychological stress before treatment and the expressions of physical reactions were stronger than in the low fear group.

Argentina↗
PubMed1989

Functional difference in monoamine transmitters in the behaviorally abnormal mouse mutant (wriggle mouse sagami).

A mutant mouse (wriggle mouse sagami, WMS) with neurological disorders was found in a colony of the BALB/c strain. The clinical signs included tremor, dystonia and involuntary movements. The concentrations of the neurotransmitter substances, noradrenaline (NA), dopamine (DA), 5-hydroxytryptamine (5-HT) and acetylcholine (ACh), were measured simultaneously with their metabolites in dissected brain regions by high-performance liquid chromatography with electrochemical detection. The turnover of 5-HT was significantly higher in the cerebral cortex, hippocampus, hypothalamus, midbrain and pons-medulla of WMS than of the genetic control, BALB/c. The intrastriatal DA and its metabolites, 3,4-dihydroxyphenylacetic acid and homovanillic acid were increased. However, there was no evidence to suggest an increase in turnover rate of this neurotransmitter. An increase in concentration of and decrease in turnover rate of NA were observed in the cerebellum of this mutant. These findings suggest that multiple disturbance of the neurotransmitter system was largely responsible for the manifestation of the clinical signs of WMS.

Acetylcholine↗
PubMed1989

[Development of a J-shaped sheath and its usefulness for angiography].

We developed a new sheath for selective trans-brachial and trans-femoral arteriography. This sheath has a J-shaped tip and can be inserted by the conventional Seldinger method using a linear dilator. This sheath was particularly useful for abdominal angiography via the brachial artery and pelvic arteriography via the femoral artery.

Angiography↗
PubMed1989

Separation and properties of multiple forms of dihydrodiol dehydrogenase from hamster liver.

1. Five multiple forms of dihydrodiol dehydrogenase (EC 1.3.1.20) with similar molecular weights of around 35,000 were purified from hamster liver cytosol. 2. All the enzymes oxidized trans-dihydrodiols of benzene and naphthalene and reduced various carbonyl compounds, but showed clear differences in specificities for other alcohols and cofactors, and in inhibitor sensitivity. 3. Two NADP+-dependent enzymes were immunologically identified with aldehyde reductase (EC 1.1.1.2) and 3 alpha-hydroxytsteroid dehydrogenase (EC 1.1.1.50). 4. The other enzymes with dual cofactor specificity oxidized xenobiotic alicyclic alcohols, and one of them was active on 3 alpha- and 17 beta-hydroxysteroids with NAD+ as a preferable cofactor.

Alcohol Oxidoreductases↗
PubMed1989

Enzymatic and chemical stability of 2',3'-dideoxy-2',3'-didehydropyrimidine nucleosides: potential anti-acquired immunodeficiency syndrome agents.

The enzymatic and chemical stability of three 2',3'-dideoxy-2',3'-didehydropyrimidine nucleosides has been studied. Chemical degradtion of the analogues was measured in the pH range of 1.0-9.0. 2',3'-Dideoxy-2',3'-didehydrocytidine (DDCN) degraded rapidly under acidic conditions, but the chemical stability was greater under basic conditions. The chemical degradation of 2',3'-dideoxy-2',3'-didehydrouridine (DDUN) and 2',3'-dideoxy-2',3'-didehydrothymidine (DDTN) was not pH dependent and was faster than that of cytarabine. Enzymatic degradation of DDCN, DDUN and DDTN was not observed in human plasma, though cytarabine was degraded enzymatically under the same conditions. DDCN was also not degraded in the presence of mouse kidney cytidine deaminase.

Acquired Immunodeficiency Syndrome↗
PubMed1989

[The clinical application of oxygen saturation pulse oximeter in otolaryngological field].

Recently, we had opportunity to use an oxygen saturation pulse oximeter (minolta pulsox-7) which is a compact, light-weight device and allows continuous, percutaneous easy determination of arterial blood oxygen saturation. We obtained the following results from clinical application of this device in the field of otorhinolaryngology. 1. There was a high coefficient of correlation (0.899) between the values of oxygen saturation determined with a Minolta Pulsox-7 and an arterial blood gas analyzer. 2. This instrument was simple to handle and was clinically applicable, and seems to be highly useful for a) timing of tracheostomy, b) objective evaluation of dyspnea, c) monitor of nasal surgery under local anesthesia.

Adult↗