Biomedical subjects

Y Ohta

Publications and source records attributed to Y Ohta.

At least 19 recordsLinked to original sources

PubMed1992

Dynamic structures of adrenocortical cytochrome P-450 in proteoliposomes and microsomes: protein rotation study.

Purified adrenocortical microsomal cytochromes P-45017 alpha,lyase and P-450C21 were reconstituted with and without NADPH-cytochrome P-450 reductase in phosphatidylcholine-phosphatidylethanolamine-phosphatidylserine vesicles at a lipid to P-450 ratio of 35 (w/w) by cholate dialysis procedures. Trypsinolysis revealed that a considerable part of each P-450 molecule is deeply embedded in the lipid bilayer, on the basis of the observation of no detectable digestion for P-45017 alpha,lyase and the proteolysis-resistant membrane-bound heavy fragments for P-450C21. Rotational diffusion was measured in proteoliposomes and adrenocortical microsomes by observing the decay of absorption anisotropy, r(t), after photolysis of the heme-CO complex. Analysis of r(t) was based on a "rotation-about-membrane normal" model. The absorption anisotropy decayed within 1-2 ms to a time-independent value r3. Coexistence of a mobile population with an average rotational relaxation time phi of 138-577 microseconds and immobile (phi > or = 20 ms) populations of cytochrome P-450 was observed in both phospholipid vesicles and microsomes. Different tilt angles of the heme plane from the membrane plane were determined in proteoliposomes to be either 47 degrees or 63 degrees for P-45017 alpha,lyase from [r3/r(0)]min = 0.04 and either 38 degrees or 78 degrees for P-450C21 from [r3/r(0)]min = 0.19, when these P-450s were completely mobilized by incubation with 730 mM NaCl. Very different interactions with the reductase have been observed for the two P-450s in proteoliposomes. In the presence of the reductase, the mobile population of cytochrome P-450C21 was increased significantly from 79% to 96% due to dissociation of P-450 oligomers.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Cortex↗

PubMed1992

Separation of hematopoietic stem cells into two populations and their characterization.

Two populations of hematopoietic stem cells (HSC) in mouse bone marrow (BM) are defined on the basis of the presence or absence of interleukin-3 (IL-3) receptor-associated antigen (IL-3RAA). HSC were purified by depletion of mature lymphoid-lineage cells followed by collection of the low-density fraction and sorting of wheat germ agglutinin-binding (WGA+) cells using a fluorescein-activated cell sorter. WGA+ cells were further separated into two populations (IL-3RAA+/WGA+ and IL-3RAA-/WGA+) by a monoclonal antibody (MoAb) against IL-3RAA. IL-3RAA+/WGA+ cells formed CFU-S on day 8; this population consisted mainly of cells in the cycling phase. IL-3RAA-/WGA+ cells form CFU-S on day 12; this population consisted mainly of dormant cells (cells in the G0 phase). When two populations obtained from C3H/HeN mice were injected into lethally irradiated (C57BL/6 x C3H/HeN)F1 mice, donor-derived cells in the peripheral blood (PB) appeared significantly earlier in mice injected with IL-3RAA+/WGA+ cells than in those injected with IL-3RAA-/WGA+ cells, whereas the reconstruction efficiency of IL-3RAA-/WGA+ cells had overtaken that of IL-3RAA+/WGA+ cells 6 weeks after injection. Long-term observation showed no significant difference between these two populations, however. The radioprotective ability (RPA) (30-day survival) of these two populations was therefore compared. The RPA of IL-3RAA-/WGA+ cells was significantly higher than that of IL-3RAA+/WGA+ cells. These findings therefore suggest that the former population is more primitive.

Animals↗

PubMed1992

[Experimental study of water jet angioplasty].

A newly invented angioplasty by using water jet energy was investigated for evaluating its safety and effectiveness in 3 dogs. The water jet was produced from a small tip nozzle (0.2 mm in diameter) of catheter by injecting 20 ml of diluted contrast medium. By using this method recanalization of femoral arterial occlusion produced by fresh thrombi was achieved in all 3 dogs. Post recanalization angiography showed no apparent small vessel occlusions. Injection apart more than 5 mm from the inner surface of human aorta provoked no apparent changes histopathologically. Water jet angioplasty may be useful in treating vascular occlusive disease.

Animals↗

PubMed1992

Comparative study of sexual dimorphism of the innominate bone in rodents and amphibians.

Sexual dimorphism in the shape of the innominate bone was demonstrated in the rat, mouse, Chinese hamster (Cricetulus griseus), frog (Ranna nigromaculata), and newt (Cynops pyrrhogaster) with a computer-assisted morphometric technique. In the rat, mouse, and hamster, ratios of ischium and pubis widths to the innominate bone length (INL) were larger in the males than in the females; however, the ratio of pubis length to INL was larger in the females than in the males. In the frog, the ratio of distance between the upper edge of the acetabulum and the lower edge of the pubis to INL was larger in males than in females. In the newt, ratios of width of ischiopubis and the longitudinal length of the ischiopubis to INL were larger in females than in males.

Animals↗

PubMed1992

In situ detection of oxidative stress in rat hepatocytes.

In rat hepatocytes in primary culture incubated with nitro blue tetrazolium, formazan content was increased by addition of t-butyl hydroperoxide, a potent oxidant, in a dose-related manner, but not by addition of valinomycin, which kills hepatocytes through mitochondrial damage. This increment after t-butyl hydroperoxide addition was not seen in hepatocytes preincubated with deferoxamine mesylate, a ferric iron chelator which inhibits radical formation. Liver perfusion with nitro blue tetrazolium and t-butyl hydroperoxide in rats produced formazan deposition faintly on the surface of hepatocytes throughout the liver and prominently in the cytoplasm of some hepatocytes, which was attenuated when performed following deferoxamine mesylate perfusion. When liver perfusion with nitro blue tetrazolium was performed in carbon tetrachloride-intoxicated rats, formazan deposition appeared diffusely in hepatocytes in the centrilobular areas. Similar deposition was also observed on the surface and in the cytoplasm of hepatocytes in the periportal and mid-zonal areas in rats undergoing post-ischaemic reperfusion. Liver perfusion with nitro blue tetrazolium can detect in situ oxidative stress in hepatocytes and may be a useful tool for studying the role of lipid peroxidation in rat liver injury.

Animals↗

PubMed1992

Presynaptic A1-purinoceptor-mediated inhibitory effects of adenosine and its stable analogues on the mouse hemidiaphragm preparation.

1. The effect of adenosine or its stable analogues (2-chloroadenosine, CADO; 5'-N-ethylcarboxamidoadenosine, NECA; and N6-cyclopentyladenosine, CPA) on the release of [3H]-acetylcholine ([3H]-ACh), and on the development of force of contraction evoked by electrical stimulation of the nerve, were studied in the mouse phrenic nerve-hemidiaphragm preparation. Evidence was obtained that the release of ACh is subject to presynaptic modulation through presynaptic A1(P1)-purinoceptors. 2. Adenosine or its stable analogues (CADO, NECA, CPA) inhibited, in a concentration-dependent manner, both the release of ACh and the force of the indirectly elicited contraction of hemidiaphragm preparation, provided in the latter case that the margin of safety was reduced by (+)-tubocurarine or magnesium. The order of potency in reducing ACh release was CPA greater than NECA greater than CADO greater than adenosine with IC50 values of 0.08 +/- 0.01, 0.74 +/- 0.05, 9.05 +/- 0.20, and 410.2 +/- 42.5 mumol/l, respectively. The order of potency in reducing twitch tension was CPA greater than NECA greater than CADO greater than adenosine with IC50 values of 0.11 +/- 0.02, 0.48 +/- 0.03, 2.07 +/- 0.49, and 240.4 +/- 20.0 mumol/l, respectively. 3. 8-Phenyltheophylline (8-PT) antagonized the inhibitory effects of the adenosine receptor agonists on ACh release and twitch tension.(ABSTRACT TRUNCATED AT 250 WORDS)

2-Chloroadenosine↗

PubMed1992

Estimation of IgG subclasses of anti-HCV (C100-3) in non-A, non-B fulminant, acute and chronic hepatitis and it's significance.

To determine whether identification of subclasses of anti-HCV IgG would help distinguish between acute and fulminant hepatitis, we assayed serum IgG subclasses of anti-HCV (C100-3) in non-A, non-B hepatitis. Anti-HCV IgG was restricted to two subclasses in different diagnostic conditions; anti-HCV IgG1 and anti-HCV IgG3. Anti-HCV IgG1 was the main subclass in acute hepatitis (AH), and was positive in all the cases and only one case was positive for anti-HCV IgG3. Anti-HCV IgG3 was the dominant subclass in fulminant hepatitis (FH). Out of the total 12 cases of FH, who were positive for either anti-HCV IgG or for any of it's subclasses, in 10 cases (83%), anti-HCV IgG3 had higher optical density (OD) values than anti-HCV IgG1 and in 6 cases (50%) was the only subclass of anti-HCV IgG being positive. In 5 cases with FH, anti-HCV IgG3 became positive even when anti-HCV IgG was negative. These findings from the basis of a new observation and are likely to be helpful in the diagnosis of non-A, non-B fulminant hepatitis.

Acute Disease↗

PubMed1992

Hepatocyte membrane stabilization by prostaglandins E1 and E2: favorable effects on rat liver injury.

When prostaglandin (PG) E1 was continuously administered to rats from 24 hours before giving a dose of carbon tetrachloride, deranged serum glutamic pyruvic transaminase levels and prothrombin time were significantly reduced 12 hours after intoxication compared with controls. A similar effect of PGE1 was seen at 24 hours in D-galactosamine-intoxicated rats. Liver histology showed a comparable attenuation of injury in these rats. These results were consistent with reported effects of PGE2, suggesting that both prostaglandins may share a common pathway in protection against liver injury. When PGE1 or 16,16'-dimethyl PGE2 was added to the medium of primary cultured rat hepatocytes, lipid peroxidation-dependent killing of the cells by tert-butyl hydroperoxide was significantly attenuated without affecting the extent of malondialdehyde accumulation compared with controls. Both prostaglandins significantly reduced the extent of increased plasma membrane microviscosity of these cells assessed by 1-[4-(trimethyl-ammonio)phenyl]-6-phenyl-1,3,5-hexatriene. PGE1 and PGE2 may possess cytoprotective effects on liver parenchymal cells through stabilization of membrane microviscosity, which may contribute to protection against liver injury.

16,16-Dimethylprostaglandin E2↗

PubMed1992

Analysis of responses to endothelins in isolated porcine blood vessels by using a novel endothelin antagonist, BQ-153.

We examined the effects of a novel ETA-selective endothelin (ET) antagonist, BQ-153, on vascular responses to ET-1 and ET-3 in isolated porcine coronary and pulmonary blood vessels, to clarify the roles of ET receptor subtypes in the regulation of vascular smooth muscle tension. With endothelium-denuded vascular tissues, the concentration-contraction curve (CCC) for ET-1 appeared as a single sigmoidal shape for all types of tissue. The CCC for ET-1 was antagonized by BQ-153 (2 and 10 microM) in all tissues, but part of the contraction was resistant. The CCC for ET-3 usually consisted of two different phases with higher (first phase) and lower (second phase) sensitivities to the peptide. Only the second phase of CCC for ET-3 was completely inhibited by BQ-153 (2 microM) in all tissues, while the first phase was resistant. The BQ-153-resistant contractile phases of ET-1 and ET-3-induced vasoconstriction appeared to have similar sensitivity in all tissues, and the contractile activity varied with each type of tissue. With endothelium-intact materials, the potencies of ET-1 and ET-3 for endothelium-dependent vasorelaxation in pulmonary artery were almost equivalent. BQ-153 (10 microM) did not inhibit ET-induced vasorelaxation. These results indicate that ET-induced vasoconstriction is mediated not only through ETA but also through ETnonA (probably ETB), and that the relative proportions of the ET-receptor subtypes mediating contractions vary in different vascular areas. In addition, results showed that ET-induced endothelium-dependent vasorelaxation is mediated through ETB.

Animals↗

PubMed1992

Mesial temporal subdural electrode as a substitute for depth electrode.

As a substitute for depth electrodes, mesial temporal subdural electrodes were devised. This electrode has a slender trapezoid shape and is easily introduced to the inner uppermost portion of the parahippocampal gyrus. Our results have shown that mesial temporal electrodes can detect not only interictal spikes but also subclinical and clinical seizure discharges from the mesiolimbic structures, and they have excellent capability for lateralization of the mesial temporal epileptic focus. If mesial temporal subdural strips are used in combination with lateral temporal subdural grids, comprehensive understanding of the focus distribution throughout the temporal lobes will be possible without using depth electrodes.

Adolescent↗

PubMed1992

Experience of a small PACS in Tottori University Hospital.

Picture archiving and communications systems (PACS) are expected to become feasible as the way of total radiologic image management. As the first step towards computerized image management, we installed an experimental small PACS with a digital optical archive for magnetic resonance and digitized radiographic film images. During the first 10 months of operation, problems were caused by the frequent mechanical troubles on the acquisition devices, impractical schemes for transmission, and troublesome retrieval and display of images. Although some of them have been solved by the improvements of both hardware and software, the mechanical instability of the digitizer and the inadequate operating procedure of the workstation still remain. As to the characteristics of PACS, the capability of access to every achieved radiologic image is the great advantage for us because the image integration has been impossible in the form of radiographic films for the traditional image management system of our hospital. However, the complicated image display procedure with high overheads is far from ideal for radiologists. The efficiency of image display must be increased to the level of a conventional film viewing system. Furthermore, research is needed on the small PACS to get consensus for the acceptance of a more widely implemented system.

Computer Systems↗

PubMed1992

Gut-derived substances in activation of hepatic macrophages after partial hepatectomy in rats.

When liver perfusion with nitro blue tetrazolium and phorbol myristate acetate was performed in rats 24 h after two-thirds liver resection, there were marked deposits of formazan converted from nitro blue tetrazolium in hepatic macrophages throughout the liver, indicating macrophage activity. The extent of the deposits was significantly reduced when perfusion was performed following oral administration of polymyxin B sulfate, a non-absorbable bacteriocidal agent against gram-negative bacilli which can also bind endotoxin lipopolysaccharides. Polymyxin B sulfate administration also attenuated the derangements of SGPT and the histological liver injury provoked by endotoxin administration after partial hepatectomy. These results suggests that gut-derived substances sensitive to polymyxin B sulfate may contribute to activation of hepatic macrophages after partial hepatectomy in rats.

Animals↗

PubMed1992

Epidemiological studies of schizophrenia in Japan.

This article examines epidemiological studies of schizophrenia in Japan. It is divided into three major sections: (1) methodological problems associated with epidemiological studies; (2) an overview of the history of epidemiology in Japan; and (3) an epidemiological study on incidence rates in Nagasaki, which was conducted as part of the World Health Organization Collaborative Study on Determinants of Outcome of Severe Mental Disorders. In general, although some differences in schizophrenic subtypes have been found, prevalence and incidence rates of schizophrenia in Japan are not significantly different from those reported in other countries.

Cohort Studies↗

PubMed1992

Lichen planus annularis: an immunohistochemical study.

Lichen planus annularis is a relatively rare skin manifestation of lichen planus. The mechanisms in the formation of annular lesions are not fully understood. We reported here a 57-year-old female with this disease. The eruption initially occurred as lichen-papules, then enlarged (bean-sized, umbilicated small plaques), and finally developed annular manifestations. We performed immunohistochemical examinations of specimens taken from different types of eruptions. In all specimens, HLA-DR was expressed in the focal keratinocytes adjacent to the dermal HLA-DR positive cell infiltration. Both in the initial papule and in the final annular lesion, expression of ICAM-1 was present only in the keratinocytes above the dermal cell infiltration, similar to HLA-DR. It is of interest that, in the umbilicated small plaques, the peripheral epidermis other than the central site extensively reacted to ICAM-1. LFA-1 expression was most prominent in the mononuclear cells impinging on the dermo-epidermal junction in all specimens. In addition, in the periphery of the umbilicated small plaques, which showed no bandlike dense cell infiltration nor degeneration of basement membrane, TNF-alpha, but not LFA-1, was positive in the infiltrated cells of the upper dermis. These results suggest that expressions of ICAM-1 and TNF-alpha in the peripheral keratinocytes and dermal infiltrated cells are important molecular events in the mechanisms of formation of the annular lesions.

Antigens, CD↗

PubMed1992

Myelin gangliosides of human peripheral nervous system: an enrichment of GM1 in the motor nerve myelin isolated from cauda equina.

Myelins of the PNS were isolated from human motor and sensory nerves of cauda equina, and their ganglioside compositions were compared. The predominant ganglioside in the human PNS myelins, both from motor and sensory nerves, was LM1 (sialosylneolactotetraosylceramide). Sialosyl-nLc6Cer and disialosyl-nLc4Cer, GD3, GM3, and GD1b were detected as common components of the two nerve myelins. Furthermore, it was revealed that the motor nerve myelin contained GM1 (about 15% of total gangliosides), whereas sensory nerve myelin contained only a trace amount of GM1 (less than 5%), by TLC analyses together with TLC immunostaining using anti-GM1 antibody. As for the disialoganglioside fraction, the content of GD1a, as well as that of GM1, differed in motor and sensory nerves. Thus, the different contents of the ganglioseries gangliosides in human motor and sensory nerve myelins were demonstrated.

Cauda Equina↗

PubMed1992

Ecological structure and incidence rates of schizophrenia in Nagasaki City.

The purpose of this study was to investigate the relationship between incidence rates of schizophrenia and residential features in Nagasaki City, Japan. Social features of residents in 259 areas in the Nagasaki City ecological structure were determined using the results of the 1980 national census. Six residential factors--employment status, occupational and academic career, household status, length of residence, housing tenure and young male predominance--were selected as factors that clearly reflect residential differentiation of residents. Contrary to the findings of many other studies conducted in Western cities, no statistically significant differences were observed, although it seemed that incidence rates were comparatively higher in the lower social classes. These results possibly reflect differences in cultural and social values and structures.

Adult↗

PubMed1992

Binding of mutagenic pyrolyzates to fractions of intestinal bacterial cells.

The binding of mutagenic pyrolyzates to cell fractions from some gram-negative intestinal bacteria and to thermally treated bacterial cells was investigated. 3-Amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1) and 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2) were effectively bound by several of the bacterial cells. The cell wall skeletons of all bacteria effectively bound Trp-P-1 and Trp-P-2. Their cytoplasmic fractions retained Trp-P-1 and Trp-P-2, but to a lesser extent than the cell wall skeletons. 2-Amino-3-methylimidazo[4,5-f]quinoline (IQ) was not found in their cytoplasmic fractions. These cell wall skeletons also bound 2-amino-6-methyldipyrido[1,2-a:3',2'-d]imidazole (Glu-P-1), 2-amino-5-phenylpyridine (Phe-P-1), IQ, 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ), and 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQX). The amount of each mutagen bound differed with the type of mutagen and the bacterial strain used. The outer membrane of Escherichia coli IFO 14249 showed binding of about 123.7 micrograms/mg of Trp-P-2, and its cytoplasmic membrane bound 57.14 micrograms/mg. Trp-P-2 bound to the bacterial cells was extracted with ammonia (5%), methanol, and ethanol but not with water.

Bacteroides fragilis↗

PubMed1992

Intestinal anisakiasis: US in diagnosis.

Eighteen consecutive patients with intestinal anisakiasis were studied with high-resolution ultrasound (US) and barium studies. US showed markedly thickened bowel loops associated with luminal narrowing, swelling of Kerckring folds, and decreased peristalsis. A small amount of ascitic fluid around the bowel loops was found, and cytologic examinations of the ascites revealed a dense infiltration of eosinophils. Barium studies demonstrated segmental mucosal edema of the small intestine: The most common site was the distal ileum, and the mean length of the edematous lesion was 19 cm. All patients underwent treatment of symptoms without laparotomy, and their symptoms disappeared by the eighth day after onset. Patients with acute abdominal symptoms should be asked about the intake of raw or undercooked fish. If the above US features are found, the diagnosis of intestinal anisakiasis must be seriously considered to avoid unnecessary surgical treatment.

Adult↗