Biomedical subjects

Hitoshi Sato

Publications and source records attributed to Hitoshi Sato.

64 records · Page 4Linked to original sources

PubMed2002

Uptake across the blood-brain barrier and tissue distribution of enterostatin after peripheral administration in rats.

Enterostatin, the N-terminal activation pentapeptide of procolipase that is produced by the pancreas, reduces food intake from high-fat diet when injected either peripherally or centrally to rats. We investigated uptake across the blood-brain barrier (BBB) and tissue distribution of enterostatin by giving radioactive-labeled enterostatin (3H-VPDPR) intravenously. Low levels of 3H-VPDPR were detected in many areas of the brain, with greatest radioactivity in the frontal cortex, hippocampus and cerebellum. Radioactivity was found in the plasma and all tissues, with the highest amount detected in the pancreas.

Animals↗

PubMed2002

The ketogenic diet upregulates expression of the gene encoding the key ketogenic enzyme mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase in rat brain.

The ketogenic diet is a clinically and experimentally effective anti-epileptic treatment whose molecular mechanism(s) of action remain to be elucidated. As a first step in defining its effects on regulation of fatty acid oxidation and ketogenesis at the genetic level, we have administered to rats: (1) a calorie-restricted ketogenic diet (KCR); (2) a calorie-restricted normal diet (NCR); or (3) a normal diet ad libitum (NAL). We have used RNase protection to co-assay diet-induced changes in abundance of the mRNA encoding the critical enzyme of ketogenesis from acetyl-CoA namely mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase (mHS) in liver and brain, together with mRNAs encoding three other key enzymes of fatty acid oxidation. We demonstrate that NCR-fed rats exhibit a significant 2-fold increase in liver mHS mRNA compared to NAL-fed rats, and that KCR-fed rats exhibit a significant 2-fold increase in both liver and brain mHS mRNA compared to NAL-fed rats. Our results demonstrate, for the first time, the effect of a ketogenic diet on gene expression in brain, and suggest possible anti-epileptic mechanisms for future investigation.

Acyl Coenzyme A↗

PubMed2002

Measuring the external exposure dose in the contaminated area near the Chernobyl nuclear power station using the thermoluminescence of quartz in bricks.

We collected bricks from buildings in the heavily contaminated evacuated area of Belarus in a 30-km zone around the Chernobyl nuclear power station and the Gomel-Bryansk area of 150-250 km from Chernobyl and estimated the cumulative radiation dose caused by the reactor accident by measuring the thermoluminescence (TL) of the bricks. The annual dose at each location was measured using glass dosimeters and thermoluminescence dosimeters (TLD). The dose rate was measured using an energy-compensated NaI scintillation survey meter. The soil contamination near the location of each brick was measured using a germanium semiconductor detector. The main purpose of the project was to extrapolate the relation between the cumulative external dose and the present dose rate or contamination level to the lower contaminated areas. The results of the glass dosimeter, TLD, and survey meter determinations were almost identical. For a determination of the annual dose higher than 10 mGy y(-1), the cumulative dose by TL (TL dose) was roughly proportional to the annual dose and about 1.5 times larger than the cumulative dose calculated from the annual dose and 137Cs half life. The difference is expected due to the contribution of short-lived nuclides immediately after the accident or localized heavy contamination of the ground surface with 137Cs that migrated afterwards. For annual dose smaller than 10 mGy y(-1), the proportionality was not observed and most of the locations facing indoors showed TL doses very much larger than that expected from the proportionality. The cumulative dose outdoors by TL was also roughly proportional to the regional 137Cs contamination level and the proportional constant is about 10(-1) mGy per GBq km(-2), and is about 250 times larger than the present annual internal dose derived from published results. The correlation between the present dose rate where the brick was sampled and the average 137Cs concentration in the ground soil near the point is not clear, possibly because of the large spatial fluctuation in the 137Cs concentration in the soil.

Cesium Radioisotopes↗

PubMed2002

Varicella-zoster virus (VZV) ORF17 protein induces RNA cleavage and is critical for replication of VZV at 37 degrees C but not 33 degrees C.

Varicella-zoster virus (VZV) open reading frame 17 (ORF17) is homologous to herpes simplex virus (HSV) UL41, which encodes the viral host shutoff protein (vhs). HSV vhs induces degradation of mRNA and rapid shutoff of host protein synthesis. An antibody to ORF17 protein detected a 46-kDa protein in VZV-infected cells. While HSV vhs is located in virions, VZV ORF17 protein was not detectable in virions. ORF17 protein induced RNA cleavage, but to a substantially lesser extent than HSV-1 vhs. Expression of ORF17 protein did not inhibit expression from a beta-galactosidase reporter plasmid, while HSV type 1 vhs abolished reporter expression. Two VZV ORF17 deletion mutants were constructed to examine the role of ORF17 in virus replication. While the ORF17 VZV mutants grew to peak titers that were similar to those of the parental virus at 33 degrees C, the ORF17 mutants grew to 20- to 35-fold-lower titers than parental virus at 37 degrees C. ORF62 protein was distributed in a different pattern in the nuclei and cytoplasm of cells infected with an ORF17 deletion mutant at 37 degrees C compared to 33 degrees C. Inoculation of cotton rats with the ORF17 deletion mutant resulted in a level of latent infection similar to that produced by inoculation with the parental virus. The importance of ORF17 protein for viral replication at 37 degrees C but not at 33 degrees C suggests that this protein may facilitate the growth of virus in certain tissues in vivo.

Animals↗

PubMed2002

Varicella-zoster virus open reading frame 2 encodes a membrane phosphoprotein that is dispensable for viral replication and for establishment of latency.

Varicella-zoster virus (VZV) encodes six genes that do not have homologs in herpes simplex virus. One of these genes, VZV open reading frame 2 (ORF2), was expressed as a 31-kDa phosphoprotein in the membranes of infected cells. Unlike equine and bovine herpesvirus type 1 ORF2 homologs that are associated with virions, VZV virions contained no detectable ORF2 protein. The ORF2 deletion mutant established a latent infection in cotton rats at a frequency and with a number of VZV genomes similar to that of the parental virus. ORF63 transcripts, a hallmark of latent infection, were present in ganglia latently infected with both the ORF2 deletion mutant and parental VZV. Thus, ORF2 is the first VZV gene shown to be dispensable for establishment of latent infection in an animal model.

Animals↗

PubMed2002

Predictive value of the adipocyte-derived plasma protein adiponectin for restenosis after elective coronary stenting.

The purpose of this study was to test the hypothesis that plasma levels of adiponectin can predict angiographic in-stent restenosis after coronary stenting. We prospectively examined adiponectin levels in 127 consecutive patients undergoing elective coronary stenting. Restenosis was defined as more than 50% stenosis at follow-up study by quantitative coronary angiography. There were no significant differences in the clinical characteristics or angiographical findings between the groups with restenosis and no restenosis. The levels of adiponectin did not differ between the restenosis group and the no restenosis group (5.7 +/- 2.8 vs 5.9 +/- 3.6 microg/mL, p = 0.72). The plasma levels of adiponectin were not related with the late loss index after coronary stenting (r = 0.01, p = 0.89). The levels of adiponectin were significantly lower in men than in women (5.5 +/- 3.2 vs 8.8 +/- 3.7 microg/ mL, p < 0.001), and negatively correlated with body mass index (r = -0.21, p = 0.01). We analyzed adiponectin levels in male, female, obese, non-obese, diabetes, and non-diabetes patients, however, there were no significant differences between the restenosis group and no restenosis group. This study has demonstrated that the measurement of adiponectin could not predict angiographic restenosis after elective coronary stenting, whereas the plasma levels of adiponectin were associated with some coronary risk factors in patients with coronary artery disease.

Adiponectin↗

PubMed2002

[Refraction-contrast bone imaging using synchrotron radiation].

The X-ray refraction-contrast imaging using synchrotron radiation with some X-ray energies is successfully performed at B120B2 of SPring-8. The refraction-contrast images of bone samples such as human dried proximal phalanx, wrist, upper cervical vertebrae and sella turcica, and as mouse proximal femur, using the synchrotron X-ray are always better in image contrast and resolution than those of the absorption-contrast images using the synchrotron X-ray and/or the conventional X-ray tube. There is much likeness in the image contrast and resolution of trabeculae bone in the human dried proximal phalanx between X-ray energy of 30 keV at sample-to-film distance of 1m and those of 40, 50 keV at those of 4,5m, respectively. High-energy refraction-constrast imaging with suitable sample-to-film distance could reduce the exposure dose in human imaging. In the refraction-contrast imaging of human wrist, upper cervical vertebrae, sella turcica and mouse proximal femur using the synchrotoron X-ray, we can obtain better image contrast and resolution to correctly extract morphological information for diagnosis corresponding to each of the clinical field than those of the absorption-contrast images.

Animals↗

PubMed2002

Heavy ion CT system based on measurement of residual range distribution.

The heavy ion CT system is proposed which is based on measurement of the residual range distribution by a fluoroscopy detector consisting of an intensifying screen and a CCD video camera. To investigate the fundamental performance of the proposed system, the spatial and density resolutions of the CT image were evaluated. The heavy ion beam 12C accelerated up to 400 MeV/u by HIMAC was used in this study. A series of projection images of two types of phantoms (PMMA pipes with several sizes and various kinds of rods with different electron densities) were experimentally taken for five values of range shifter thickness at each projection angle. From these images, the residual range distribution was obtained and used to reconstruct CT images of the relative stopping power which were obtained by the filtered back projection method with the Shepp-Logan filter after noise reduction processing by the median filter. As a result, the spatial resolution was found to be less than 2 mm and the relative density resolution around the density of water was less than 0.07.

Fluoroscopy↗

PubMed2001

Varicella-zoster virus gH:gL contains a structure reactive with the anti-human gamma chain of IgG near the glycosylation site.

Varicella-zoster virus (VZV) glycoproteins were purified from infected cells using monoclonal antibodies and gH:gL was found to react with antibodies to the gamma chain of human IgG (h-IgG), whereas gE:gI and gB did not. When gH:gL was captured by concanavalin A, it lost reactivity with the anti-h-IgG gamma chain (anti-h-gamma-IgG). gH:gL reacted with anti-h-gamma-IgG in an ELISA assay and gave a K:(d) value of 2.16x10(-7) M in a BIAcore assay. The K:(d) value of the human monoclonal antibody to gH (TI-57) used for the purification of gH:gL was 4.45x10(-10) M. Virus pretreated with anti-h-IgG was five times more resistant to neutralization with TI-57. Although the nature of the binding was not clear, gH:gL bound to anti-h-gamma-IgG. If this interaction results from immunological similarity between gH:gL and h-IgG, it may cause immune evasion in the pathogenesis of VZV infection.

Antibodies, Monoclonal↗

PubMedDate not supplied

Effect of artificial lung compliance on in vivo pulmonary system hemodynamics.

This study examined the effect of artificial lung compliance (C) on pulmonary system (PS) impedance and right ventricular function during in-series attachment of the MC3 Biolung in adult sheep. Compliances, C, of 0-20 ml/mm Hg were tested at the Biolung inlet. Results indicate the PS 0 harmonic input impedance modulus was not affected by C. The PS first harmonic input impedance modulus (Z1) was 10.9 +/- 3.2 mm Hg/(l/min) at C = 0 ml/mm Hg and minimized to 2.41 +/- 0.79 mm Hg/(l/min) at C > or = 0.5 ml/mm Hg. Cardiac output was 58% +/- 10% of its pre-Biolung attachment, baseline value at C = 0 ml/mm Hg and was maximized to an average of 75% +/- 11% at C > or = 0.5 ml/mm Hg. The left ventricular lateral-to-anteroposterior axis length ratio, which decreases with leftward septal shift, increased with C from 0.52 +/- 0.12 at C = 0 ml/mm Hg to 0.76 +/- 0.06 at C = 5 ml/mm Hg (p < 0.05), but decreased slightly with C at C > 5 ml/mm Hg. Therefore, the ideal C for right ventricular function is at least 0.5 ml/mm Hg and may be as high as 5 ml/mm Hg to minimize septal shift.

Animals↗