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Biomedical subjects

M Shibata

Publications and source records attributed to M Shibata.

At least 325 records · Page 18Linked to original sources
PubMed1996

[Study on the specificity of a monoclonal antibody against recombinant envelope proteins of a human endogenous retrovirus, ERV3].

Human endogenous retroviruses (HERVs) and its related sequences have been known to occupy about 1% on human genome, and the expression of messenger RNA has been demonstrated by many investigators including our laboratory. However, only few papers have been indicated they are translated in proteins. Either physiological roles in man or pathogenic roles in diseases are still unknown at present. In this study, to investigate the protein expression of one copy type HERV, ERV3 and its pathogenicity, a recombinant protein to ERV3 env region was produced using E. coli expression system, and a monoclonal antibody to the recombinant protein was prepared. The monoclonal antibody evidenced the translation of ERV3, and 170 and 180 kilodaltons of proteins were detected in normal placentas and adrenal glands by Western blot. Natural antibodies to the products of ERV3 env region with high reactivities were detected in sera from some patients with systemic lupus erythematosus (SLE) compared with normal population and patients with rheumatoid arthritis (RA). The result suggests that ERV3 products may play as one of autoantigens in patients with SLE. The recombinant protein and monoclonal antibody described here may be useful to study the role of ERV3 in vivo and the etiologic relation of HERVs to autoimmune diseases.

Animals↗
PubMed1996

[Arrhythmias in ischemic heart disease].

In ischemic heart disease the degree and the size of myocardial damage by ischemia will change with time, and the mechanism of arrhythmias will change combining multiple factors for arrhythmias complicatedly. So we should cure the patients taking their condition of illness into account. We explain the diagnosis, complication, treatment, and prognosis of ischemic heart disease.

Arrhythmias, Cardiac↗
PubMed1996

[Clinical significance of anti-centromere antibody and anti-CENP-B antibody in sera of patients with primary biliary cirrhosis].

Anti-centromere antibody (ACA) have been recognized in sera of patients with primary biliary cirrhosis (PBC) and CREST syndrome. The major reactive antigen of ACA have been identified as CENP-B (80kDa). Using an indirect immunofluorescence (IIF) method and ELISA method, we detected ACA and anti-CENP-B antibody in patients with PBC and various liver diseases and collagen diseases. We tested sera of 44 patients with PBC, 8 patients with autoimmune hepatitis (AIH), 51 patients with chronic hepatitis B (CH-B), 312 patients with chronic hepatitis C(CH-C), 12 patients with progressive systemic sclerosis (PSS), 10 patients with systemic lupus erythematosus (SLE), 10 patients with rheumatoid arthritis (RA), and 30 with healthy subjects (HS). ACA was detected by IIF technique, using HEp-2 cell and fluoro-CENTRO slides (MBL) as substrates. Anti-CENP-B antibody was detected by ELISA method using recombinant CENP-B (MBL) as the antigen. ACA was detected in sera of 12 (27%) patients with PBC, two (25%) patients with AIH, five (2%) patients with CH-C, nine (75%) patients with PSS, and one (10%) patients with RA. ACA was not detected in sera of patients with CH-B and SLE and in HS. The results of IIF test for ACA, using HEp -2 cells and fluoro-CENTRO slides, were completely agreed. Anti-CENP-B antibody was detected in 28(97%) out of 29 patients sera positive for ACA. The titers of ACA and anti-CENP-B antibody did not show a correlation (r = 0.24). Out of 12 sera, in which, the titers of anti-CENP-B antibody was over 400. Among them, eight were patients with PBC and four were PSS. Later, out of four patients with PSS, three (75%) were found to be positive for anti-mitochondrial antibody. Out of five patients, in which the titer of anti-CENP-B antibody showed over 800, all were patients with PBC. The titers of ACA have no relationship with PBC. However, the titers of anti-CENP-B antibody have closed relationship with PBC. The reason why the titers of ACA and anti-CENP-B antibody were not correlated is unknown. We consider anti-CENP-B antibody is a new marker of a subset of PBC, because almost all the patients were PBC when this antibody showed over 400.

Arthritis, Rheumatoid↗
PubMed1996

Hepatic hemorrhage in malignant rheumatoid arthritis.

Intrahepatic hemorrhage is a serious and life-threatening complication in liver disease. We describe a patient who had two episodes of intrahepatic hemorrhage after having malignant rheumatoid arthritis for 8 yr. Abdominal CT scans revealed a large intrahepatic, subcapsular hematoma. Arteriography demonstrated irregularity, caliber change, and pseudoaneurysms of the right hepatic artery, suggesting vasculitis as a cause of the bleeding. The hemorrhage was first treated with transcatheter arterial embolization, which failed to exert long term control, but arterial infusion of a large dose of prednisolone when the hemorrhage appeared was successful in managing it.

Adult↗
PubMed1996

[Hypertrophic obstructive cardiomyopathy with ruptured chordae tendineae: a case report].

A 61-year-old man with hypertrophic obstructive cardiomyopathy and ruptured chordae tendineae but subsequent disappearance of the obstruction received mitral valve replacement 4 years after the diagnosis of ruptured chordae tendineae. Chordal rupture should be recognized as one of the important causes of mitral regurgitation in patients with hypertrophic obstructive cardiomyopathy.

Cardiomyopathy, Hypertrophic↗
PubMed1996

[A new embedding material for morphometry: Shiojirin E-10].

For morphometric studies, sections have been stained with the Luxol fast blue-PAS-Hematoxylin (LPH) staining method after secondary fixation with chromic acid followed by embedding in Celloidin to measure the area of nerve cells or axons with the help of an image analyzer and a microscope. However, the manufacture of Celloidin has been suspended in Japan. Therefore, we studied the use of Shiojirin E-10 (10% nitrocellulose ether alcohol solution) as a substitute embedding material, and compared it with Celloidin from the viewpoint of tissue shrinkage and staining characteristics. Regarding the shrinkage ratio of LPH-stained sections of human cauda equina, there was no practical difference in the axonal areas (p < 0.01) between Celloidin sections (4.31 +/- 2.55 microns2) and Shiojirin E-10 sections (4.14 +/- 2.20 microns2). Regarding staining characteristics, we introduced a hue analysis method using computerized digital signals converted from pictures of stained sections taken by a videocamera. For the evaluation of hue, we examined the H-E sections of mouse liver and kidney, and the LPH sections of the human cauda equina. The hematoxylin hues of the H-E sections were 295 degrees for Celloidin and 294 degrees for Shiojirin E-10. Eosin hues of the E-E sections were 320 degrees for both embedding material. The axonal hues of the LPH stain were 254 degrees for Celloidin and 251 degrees for Shiojirin E-10. Myelin sheath hues were 224 degrees for both embedding material. According to our results, Shiojirin E-10 can be substituted for Celloidin from the qualitative and quantitative viewpoints in the morphologic studies.

Animals↗
PubMed1995

Chemoprevention by dehydroepiandrosterone and indomethacin in a rat multiorgan carcinogenesis model.

The chemopreventive efficacy of dehydroepiandrosterone (DHEA) and indomethacin (IM) alone or in combination was investigated in a rat multiorgan carcinogenesis model. These two chemicals were selected as chemopreventive agents with different functions. Animals were sequentially given five carcinogens with different organ target sites in the first 4-week initiation period. One week after its completion, the rats received 0.3% DHEA in the diet, 20 ppm IM in the drinking water, or 0.3% DHEA + 20 ppm IM until experimental week 28. DHEA enhanced hepatocarcinogenesis, but concurrent treatment with IM suppressed tumor development as compared to the DHEA group. DHEA inhibited tumor development in the thyroid, with a similar tendency observed for the small intestine. In addition, treatment with this hormone decreased occurrences of preneoplasias in the urinary bladder and seminal vesicles. Treatment with IM clearly suppressed development of preneoplasias or neoplasias in the lung and small and large intestines. In the urinary bladder, treatment with IM tended to decrease preneoplastic lesion development. Analysis of multiplicity of total tumors of any category revealed comparable values for DHEA and control groups, while the IM group showed a significant reduction. IM in combination with DHEA caused suppression as compared to DHEA alone. In a separate 8-week experiment, DHEA or IM were administered for 4 weeks after prior carcinogen application, and biochemical responses in the target organs were investigated. DHEA increased glucose-6-phosphate dehydrogenase levels in the liver but caused a decrease in the small intestine. In addition, DHEA decreased serum T4 but not T3. IM decreased prostaglandin E2 content in the small intestine. In conclusion, although DHEA or IM exert significant chemopreventive effects in multiorgans with the exception of the DHEA-treated liver case, treatment in combination did not result in amplification of their beneficial influence. Our results suggest the possible application of IM for chemoprevention in high-risk individuals, but the question of effects of DHEA in the liver must be answered before this hormone can be considered for use in humans.

Animals↗
PubMed1995

ATP-sensitive K+ channels mediate regulation of substance P release via the prejunctional histamine H3 receptor.

Perfusion of histamine (10(-3) M) elicited a significant increase of immunoreactive substance P release in the subcutaneous perfusate in the rat hindpaw. The active L-enantiomer of cromakalim, lemakalim (50 micrograms/kg, i.v.), a selective K+ channel activator, significantly inhibited the immunoreactive substance P release. Glibenclamide (10 mg/kg, i.v.), an ATP-sensitive K+ channel blocker, abolished the response to lemakalim on the release of immunoreactive substance P. R(-)-alpha-methylhistamine (1 mg/kg, i.v.), a specific histamine H3 receptor agonist, significantly inhibited the release of immunoreactive substance P. Glibenclamide (10 mg/kg, i.v.) antagonized the inhibitory effect of R(-)-alpha-methylhistamine. Tetraethylammonium (10 mg/kg, i.p.), a K+ channel blocker, also reduced the inhibitory effect significantly. These results suggest that the inhibition of substance P release from sensory nerve endings via prejunctional histamine H3 receptors may be achieved by activating the ATP-sensitive K+ channel coupled to the histamine H3 receptor in the rat skin.

Adenosine Triphosphate↗
PubMed1995

Regulation of substance P release mediated via prejunctional histamine H3 receptors.

The involvement of the histamine H3 receptor in the regulation of substance P release in neurogenic inflammation was studied by using rat hindpaw skin. R-(-)-alpha-Methylhistamine, a specific histamine H3 receptor agonist, significantly inhibited the increased vascular permeability induced by antidromic electrical stimulation of the sciatic nerve in a dose-dependent manner at doses of 0.5-3 mg/kg (i.v.), and thioperamide (2 mg/kg i.p.), a specific histamine H3 receptor antagonist, prevented the inhibitory effect of R-(-)-alpha-methylhistamine. The antidromic stimulation also caused a significant increase in immunoreactive substance P release in the subcutaneous (s.c.) perfusate in the rat hindpaw. R-(-)-alpha-Methylhistamine (0.25-2 mg/kg) dose dependently inhibited the increase in release of immunoreactive substance P, and thioperamide (2 mg/mg i.p.) antagonized it. Perfusion of histamine (10(-3) M) elicited a significant increase of immunoreactive substance P release in the perfusate, which was reduced by R-(-)-alpha-methylhistamine and the antagonism of thioperamide was also observed. Histamine (in the presence of histamine H1 and H2 receptor antagonists) had an inhibitory effect on the electrically evoked release of immunoreactive substance P. These results strongly support the hypothesis that histamine regulates substance P release via prejunctional histamine H3 receptors that are located on peripheral endings of sensory nerves.

Animals↗
PubMed1995

Secondary structure in solution of two anti-HIV-1 hammerhead ribozymes as investigated by two-dimensional 1H 500 MHz NMR spectroscopy in water.

Two hammerhead chimeric RNA/DNA ribozymes (HRz) were synthesized in pure form. Both were 30 nucleotides long, and the sequences were such that they could be targeted to cleave the HIV-1 gag RNA. Named HRz-W and HRz-M, the former had its invariable core region conserved, the latter had a uridine in the invariable region replaced by a guanine. Their secodary structures were determined by 2D NOESY 1H 500 MHz NMR spectroscopy in 90% water and 10% D2(0), following the imino protons. The data show that both HRz-M and HRz-W form identical secondary structures with stem regions consisting of continuous stacks of AT and GT pairs. An energy minimized computer model of this stem region is provided. The results suggest that the loss of catalytic activity that is known to result when an invariant core residue is replaced is not related to the secondary structure of the ribozymes in the absence of substrate.

Base Sequence↗
PubMed1995

Capillary-tissue arrangement in the skeletal muscle optimized for oxygen transport in all mammals.

The aim of this computer simulation study is to evaluate the efficiency of capillary networks in the skeletal muscle for oxygen (O2) delivery to tissue for all mammals. This was performed by: (1) employing Krogh's cylinder model for the capillary-tissue system and the minimum volume model for the vascular system, (2) allometrically assessing the muscle blood flow and O2 consumption rate (the main input data) in the resting and exercising states as power functions of body weight from the data reported for several mammals, and (3) calculating the cost-performance of the system from the ratio (maximum O2 uptake of tissue)/(minimum energy expenditure of blood flow supply), as a function of number of capillaries. The results obtained for body weights ranging from 100 g to 1000 kg revealed that for each body weight and metabolic state, the efficiency curve attains a peak at a specific optimum capillary number, and that the calculated values of total muscle mass, capillary density, and capillary flow-rate by using the optimum capillary number and tissue radius during exercise agree remarkably well with those actually measured in various animals. These findings suggest the validity of a working hypothesis that in all mammals, the capillary arrangement in the skeletal muscle is optimized for O2 delivery to tissue during exercise.

Animals↗
PubMed1995

A new fluorescence microscopy for tomographic observation of microcirculation by using dual-beam slit laser illumination.

By designing a new epi-illumination system with dual slit laser beams, we have developed a fluorescence microscope for tomographic observations of in vivo microcirculation. Two beams of an Argon ion laser were converted into thin slit beams of thickness 28 to 60 microns by optical lenses and were illuminated onto tissue to intersect at the focal plane of the objective. The fluorescent light emitted from a FITC tracer by this cross-illumination was picked up by the microscope through a filter, with no "out of focus" noise from the tracer above and below the crossing zone. The results of in vitro experiments by using glass micropipettes (20-80 microns i.d.) filled with FITC-dextran and skeletal muscle tissue certified uniform tracer excitation in the crossing zone and the augmentation of the beam thickness due to light scattering in the tissue to be 1.7 and 2.5 times at depths of 100 and 200 microns from the surface, respectively. In vivo tests in the rabbit tenuissimus muscle revealed that this system can realize microvasculature tomography, with adequate vertical zone selectivity and spatial resolution to reconstruct its three-dimensional mapping, and long-term monitoring of tracer leakage from a single capillary to the surrounding tissue, with sufficient quantitative reliability to determine the capillary permeability and its heterogeneity along the channel.

Animals↗
PubMed1995

Central mechanism of neural activation with cold acclimation of rats using Fos immunohistochemistry.

The expression of Fos protein in the rat diencephalon, brain stem, cerebellum, and spinal cord was investigated using immunohistochemistry during chronic cold exposure, in order to clarify the neural regions involved in the thermoregulatory responses and the central mechanism of neural activation with cold acclimation. Numerous Fos-positive cells were observed in many brain regions after cold exposure and changes in the number of Fos-positive cells were analyzed quantitatively. Fos-positive regions were classified into three groups on the basis of the expression period of Fos protein. The first group was where a significant number of Fos-positive cells were seen 3 h and 24 h after cold exposure, but not observed 14 days after exposure; the regions included the lateral septal nucleus (LS), parvocellular paraventricular hypothalamic nucleus (pPVN), posterior hypothalamic area (PH), supramammillary nucleus (SuM), locus coeruleus (LC), dorsal tegmental nucleus (DTg), vestibular nucleus (Ves), and nucleus of solitary tract (Sol). The second group was where a significant number of Fos-positive cells were found 3 h, 24 h and 14 days after cold exposure; the regions included the preoptic hypothalamic area (POA), paraventricular thalamic nucleus (PV), lateral preoptic area (LPO), zona incerta (ZI), subparafascicular thalamic nucleus (SPF), lateral dorsal central grey (CGLD), lateral ventral central grey (CGLV), microcellular tegmental nucleus (MiTg), lateral lemniscus nucleus (LL), dorsal parabrachial nucleus (DPB), and the cerebellum. The third group was where Fos-positive cells were more numerous 14 days after cold exposure than they were after 3 h and 24 h of exposure; these regions included the ventromedial hypothalamic nucleus (VMH) and the spinal cord. These results demonstrate that the numbers and regions of Fos-positive cells in the rat brains changed during chronic cold exposure, and such changes may reveal the cellular adaptation of the thermogenic responsive neurons in the rat brain to cold acclimation.

Adaptation, Physiological↗
PubMed1995

Differences in Fos expression in the rat brains between cold and warm ambient exposures.

Fos expression in the rat diencephalon, brain stem, cerebellum, and spinal cord was examined after warm (33 degrees C) and cold (10 degrees C) ambient exposures. Fos expression was examined with use of immunohistochemical method and the number of Fos-positive neurons in each nucleus was quantitatively analyzed. When rats were exposed to cold ambient, significant number of Fos-positive neurons was found in the lateral septal nucleus (LS), preoptic hypothalamic area (POA), parvocellular paraventricular hypothalamic nucleus (pPVN), lateral preoptic area (LPO), zona incerta (ZI), paraventricular thalamic nucleus (PV), ventromedial hypothalamic nucleus (VMH), subparafascicular thalamic nucleus (SPF), posterior hypothalamic area (PH), supramammillary nucleus (SuM), microcellular tegmental nucleus (MiTg), lateral lemniscus nucleus (LL), lateral dorsal central grey (CGLD), lateral ventral central grey (CGLV), dorsal parabrachial nucleus (DPB), locus coeruleus (LC), dorsal tegmental nucleus (DTg), vestibular nucleus (Ves), nucleus of solitary tract (Sol), spinal cord, and cerebellum. When animals were exposed to warm ambient, the numbers of Fos-positive neurons in the LS, POA, PV, LPO, and SuM were significantly increased to be equal to those of cold ambient. However, after warm ambient exposure the numbers of Fos-positive neurons in the DPB and spinal cord were increased but less than those of cold ambient, and those in the pPVN, VMH, ZI, SPF, PH, CGLD, CGLV, MiTg, LL, LC, DTg, Ves, Sol, and cerebellum were not significantly increased as compared with those of control or cold ambient. Abdominal temperature was not changed during cold ambient exposure, but the temperature was significantly increased during warm ambient exposure.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Relationship between the phasic period of interdigestive migrating contraction and the systemic bioavailability of acetaminophen in dogs.

The relationships of the phasic period of interdigestive migrating contraction to gastrointestinal (GI) transit of drugs and their oral absorption were investigated in mongrel dogs by simultaneous oral dosing of acetaminophen (AAP) and salicylazosulfapyridine (SASP) at the starting points of the phase I and phase III periods of gastric contractions. Strain-gauge force transducers were surgically sutured onto the serosa of the GI tracts in the dogs to measure the interdigestive migrating contractions. The mean absorption time of AAP and the time for the first appearance of sulfapyridine (a bacterial metabolite of SASP in the colon) in plasma were used as the indices of gastric emptying time (GET) and small intestinal transit time (SITT), respectively. In individual dogs, the GET and the SITT at phase I showed a clear delay in comparison with those at phase III. For AAP used as a marker compound here, the systemic bioavailability after oral dosing to intact beagle dogs at doses of 3, 10, and 20 mg/kg was about 55, 63, and 79%, suggesting that AAP undergoes a non-linear hepatic clearance. At a dose of AAP 20 mg/kg, the systemic bioavailability of AAP was 100% in the case of dosing at phase III, but was reduced by half when dosing at phase I. These results indicate that, in oral dosing, the transit of drugs through the GI tract was clearly affected by the phases of gastric contractions.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetaminophen↗