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Biomedical subjects

S Satoh

Publications and source records attributed to S Satoh.

At least 397 records · Page 22Linked to original sources
PubMed1995

Factors influencing the intestinal phase of pancreatic exocrine secretion in the turkey.

The present study was done to investigate the factors regulating the intestinal phase of exocrine pancreatic secretion in the turkey. The intestine of turkeys equipped with pancreatic fistulas was perfused with peptone solution, fat emulsion and hydrochloric acid (HCl), and pancreatic flow and protein output were measured. Neither peptone solution nor fat emulsion had any effects on pancreatic secretion. HCl enhanced the flow rate of pancreatic juice but not protein output. To clarify the neural mechanism of this phenomenon, the vagal postganglionic blocker atropine was continuously infused and pancreatic secretion in response to intestinal HCl was measured. Atropine completely suppressed both pancreatic flow and protein output. It is suggested that the avian intestinal phase of pancreatic secretion is mainly controlled by cholinergic action though HCl stimulation.

Animals↗
PubMed1995

Effects of selective vagotomy on circadian rhythms of plasma glucose, insulin and food intake in control and ventromedial hypothalamic (VMH) lesioned rats.

Effects of hepatic and celiac vagotomy on circadian rhythms of plasma glucose, insulin, and food intake were examined in sham-operated (control) and ventromedial hypothalamic (VMH) lesioned rats. Rats were acclimated to the condition with a 12-hour light-dark cycle for 1 week before surgery. One week after VMH lesions, control and VMH lesioned rats were divided into three groups: sham vagotomy, hepatic vagotomy, and celiac vagotomy. Three days after vagotomy, food intake was measured at 6-hour intervals. Seven days after vagotomy, plasma glucose and insulin were measured at the midpoint of each feeding period. In control rats, hepatic vagotomy destroyed circadian rhythms of plasma glucose and insulin probably due to removal of afferent function. In VMH lesioned rats, celiac vagotomy destroyed circadian rhythm of food intake due to the reduction of plasma insulin by removal of efferent function without affecting the loss of circadian rhythms of plasma glucose and insulin.

Afferent Pathways↗
PubMed1995

Antenatal sonographic detection of the proximal esophageal segment: specific evidence for congenital esophageal atresia.

To determine the biologic significance of a transient anechoic area observed in the midline of the fetal neck when attempting an antenatal ultrasound diagnosis of congenital esophageal atresia (CEA), a prospective study was made in 10 cases presenting both polyhydramnios and an unusually small stomach size due to a decrease in fetal stomach fluid. There were 8 cases indicating a transient anechoic area in the fetal neck, all of which were diagnosed as having CEA postnatally by plain roentgenogram, neonatal surgery, or autopsy findings. The remaining 2 cases had no CEA; one had Nager's syndrome and the other, a disorder involving neuronal migration in the central nervous system. These results suggest that an anechoic area in the middle of the fetal neck can be used as an indication of CEA and also for differentiating this condition from diseases with possible swallowing impairment.

Esophageal Atresia↗
PubMed1995

Expression of connexin 32 gap junction protein in the kidneys during fetal development of the hamster (Mesocricetus auratus).

The expression of gap junction protein was examined immunohistochemically using affinity-purified antibody against rat liver gap junction protein, connexin 32 (Cx32), in the kidneys of fetal (gestation days 13-16) and adult Syrian golden hamsters. Phalloidin histochemical staining, PNA- and RCA I-lectin staining, NCAM immunostaining, and alkaline phosphatase and Na(+)-K(+)-ATPase enzyme-histochemical staining were performed in combination with Cx32 immunostaining. The kidney sections were observed with a confocal scanning laser microscope. By gestation day 13, Cx32 immunoreactivity was observed in the differentiating tubules. The Cx32 staining was localized on the lateral cell membrane of the cells lining the developing proximal tubules, while the S-shaped bodies, developing distal tubules, and collecting tubules showed no positive immunostaining. As the kidney developed, the density of Cx32 immunoreactivity increased. As the gap junction provides pathways for cell-cell communication, the development of Cx32 expression may imply that this structure plays an important role in renal tubule development. Confocal scanning laser microscopy provided a clear image of the fluorescence-labeled cell structures, free from out-of-focus blur. Using the same sections, stereoscopic images were easily reconstructed from serial optical sections, and were helpful in understanding the spatial distribution of Cx32 expression in the developing fetal proximal tubules.

Animals↗
PubMed1995

Expression rate of cytokine mRNA in the liver of chronic hepatitis C: comparison with chronic hepatitis B.

This study was carried out to test the hypothesis that, in chronic hepatitis (CH), inflammatory processes, including viral replication, host immune response, and hepatocyte destruction, are regulated by a cytokine network in the liver. Expression of the mRNA of the cytokines IL1-beta, IL2, IL4, IL5, IL6, TNF-alpha, and IFN-gamma, the lymphocyte markers CD4 and CD8, and the HLA class I molecule, beta 2-microglobulin (B2MG) in the liver tissue of 20 CH(C) cases and 9 CH(B) patients was investigated by the reverse transcription polymerase chain reaction (RT-PCR) method. TNF-alpha, CD4, and B2MG mRNA were detected in 100% of cases of in both CH(B) and CH(C). The expression rates of IL1-beta, IL2, IL4, IFN-gamma, and CD8 mRNA were 80%, 40%, 25%, 40%, and 80% in CH(C) and 88.9%, 44.5%, 30%, 55.6%, and 100% in CH(B). IL6 mRNA was detected only in CH(B), in 22.2% of cases, IL5 mRNA was not detected in either CH(B) or CH(C). IL2, IL4, and IFN-gamma mRNA were expressed significantly more frequently in patients who had high serum ALT and a high histological activity index (HAI) score. There was no difference in cytokine expression between CH(B) and CH(C), except in IL6, suggesting the existence of a common immunopathogenesis for CH(B) and CH(C). In chronic viral hepatitis, IL1-beta and TNF-alpha appear to play a major role in immune responses and IL2, IL4, and IFN-gamma seem to be associated with increased cytotoxic T cell response.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Predominance of the mutation at 1138 of the cDNA for the fibroblast growth factor receptor 3 in Japanese patients with achondroplasia.

Fibroblast growth factor receptor 3 (FGFR3) has recently been identified as a putative gene for achondroplasia. Since a guanine to adenine mutation at 1138 of the cDNA for FGFR3 had been identified in most of the patients in Western population, we examined 13 Japanese patients to see if they also share the same mutation. Specific endonuclease digestion of the amplified coding sequence for the transmembrane domain of the FGFR3 revealed that the 12 patients have the G to A change at 1138, while the other had the G to C substitution at the same point, both of which result in G380A substitution. As far as we studied, the homogeneity of the point mutation at 1138 is also authentic to Japanese patient as well as Western patients.

Achondroplasia↗
PubMed1995

Breech presentation: is there a difference in eye movement patterns compared with cephalic presentation in the human fetus at term?

OBJECTIVE: Our purpose was to characterize eye movement patterns in the human fetus at term persisting in breech presentation. STUDY DESIGN: Studied were 11 fetuses in breech presentation and 12 in cephalic presentation at 36 to 41 weeks' gestation, of which the presentation remained unchanged from 32 weeks' gestation until delivery. With real-time ultrasonography we analyzed three measurements by means of the Mann-Whitney rank-sum test: (1) duration of eye-movement and no-eye-movement periods, (2) frequency of eye movements, and (3) proportion of horizontal, vertical, and oblique eye movements. RESULTS: There were significant differences in the eye movement directions between breech and cephalic fetuses: horizontal (median 70.3% vs 80.2%), vertical (17.4% vs 11.0%), and oblique (13.1% vs 9.1%), respectively. No differences were noted in the duration of eye-movement and no-eye-movement periods or in the frequency of eye movements. CONCLUSION: Eye movement pattern, in direction, of term fetuses persisting in breech presentation run on a different in-utero developmental course of neural control from those in cephalic fetuses.

Breech Presentation↗
PubMed1995

A novel apparatus that permits multiple routes for infusions and body-fluid collections in a freely-moving animal.

A novel apparatus is described for simultaneous performance of multi-channel infusions/body-fluid collections and multichannel electrical recordings/stimulations in a freely behaving animals. This apparatus consists of a cylindrical cage and other devices described below. Electrical contacts are achieved via a slip-ring commutator. A rotation detector detects the turning of the animal in the cage, and a controller rotates the floor under the animal in the opposite direction by means of a stepping motor. Thus, excessive twisting of the fluid tubing between the animal and experimental equipment is released by rotation of the floor. Floor rotation starts when the animal turns in either direction and exceeds a present number of rotations. When the turning exceeds certain rates, the floor is rotated with higher angular velocities. This floor rotation little affected sleep-wake activities, brain temperature, food and water intake, and general behavior of the rat. Thus, multi-channel fluid routes have been realized; and by excluding the swivel apparatus from the fluid lines, advantages such as no fluid leakage at the swivel, no extra dead volume, and low torque to rotate the device have been gained.

Animals↗
PubMed1995

Cromakalim suppresses hypertonic saline-induced renal vasoconstriction in anaesthetized dogs.

1. Intrarenal arterial infusion of hypertonic saline (HS) transiently increased and then gradually reduced renal blood flow (RBF) in anaesthetized dogs. Glomerular filtration rate (GFR) but not filtration fraction decreased at the end of the infusion. 2. In the presence of a potassium channel opener cromakalim (0.3 microgram/kg per min), HS infusion failed to reduce RBF; the initial increase in RBF was maintained throughout the infusion. Since cromakalim also prevented the decrease in GFR, HS infusion lowered filtration fraction. 3. The results suggest that cromakalim inhibits both pre-and postglomerular vasoconstriction induced by HS infusion.

Animals↗
PubMed1995

Effect of renal nerve denervation on tissue catecholamine content in spontaneously hypertensive rats.

1. To clarify the possible role of tissue catecholamines in the development of hypertension, we investigated the effect of bilateral renal denervation on the catecholamine contents of central and peripheral tissues in spontaneously hypertensive rats (SHR). 2. Norepinephrine (NE) content in renal cortex, renal medulla, and adrenal gland was higher in 7 week old SHR than age-matched Wistar-Kyoto rats (WKY). Dopamine (DA) content in the brainstem and hypothalamus was also higher in SHR, but NE and epinephrine (EPI) content in these areas were not different between strains. Similar differences in catecholamines were observed in 9 week old rats in which a sham operation of bilateral renal denervation was performed 2 weeks previously. 3. Bilateral renal denervation produced an almost complete reduction of NE content in the kidney in both strains and prevented the development of hypertension. DA content in the brainstem was also decreased by renal denervation in SHR but not in WKY. NE and EPI content in central tissues were not affected by renal denervation. 4. These results suggest that DA content in brainstem area, as well as NE content in the kidney, have a relationship in the development of hypertension in SHR.

Animals↗
PubMed1995

Clinical use of low porosity woven ultrafine polyester fiber grafts.

A woven fabric graft made of ultrafine polyester fibers (UFPF) (Toray Graft, water porosity: 100 ml/min/cm2:120 mm Hg H2O) was clinically applied in 81 cases (28 thoracic aortic aneurysms, 6 thoracoabdominal aortic aneurysms, 42 abdominal aortic aneurysms, and 5 atherosclerotic obstructions of the peripheral arteries). Eight patients died after surgery due to causes unrelated to the graft. The other 73 patients were in good condition after surgery. For operations requiring extracorporeal circulation, the graft was presealed with human albumin. For the abdominal aortic aneurysms, the graft was preclotted in situ with nonheparinized autoblood after the completion of the proximal anastomosis. It took about 2 min to complete the preclotting. A nonsealed graft was used for the reconstruction of peripheral arteries for the intraaortic balloon pumping procedure. The graft was easy to handle. There was no cut edge fraying problem with the graft in any direction of cutting. Even after presealing, the graft was soft and pliable enough to enable easy adaptation and anastomosis. Just after implantation, bleeding was minimal from the graft wall, anastomotic sites, and suture pores, and it stopped spontaneously. These clinical data showed that the woven UFPF graft exhibited both easy handling despite in spite of low porosity and safe application in the reconstruction of arterial systems even under totally heparinized conditions during extracorporeal circulation.

Aortic Aneurysm↗
PubMed1995

Hepatitis C virus-encoded nonstructural protein NS4A has versatile functions in viral protein processing.

A transient protein expression system in COS-1 cells was used to study the role of hepatitis C virus (HCV)-encoded NS4A protein on HCV nonstructural polyprotein processing. By analyzing the protein expression and processing of a deletion mutant polypeptide, NS delta 4A, which encodes the entire putative HCV nonstructural polyprotein except the region encoding NS4A, the versatile functions of NS4A were revealed. Most of the NS3 processed from NS delta 4A was localized in the cytosol fraction and was degraded promptly. Coproduction of NS4A stabilizes NS3 and assists in its localization in the membrane. NS4A was found to be indispensable for cleavage at the 4B/5A site but not essential for cleavage at the 5A/5B site in NS delta 4A. The functioning of NS4A as a cofactor for cleavage at the 4B/5A site was also observed when 30 amino acids around this site was used as a substrate and a serine proteinase domain of 167 amino acids, from Gly-1049 to Ser-1215, was used as an enzyme protein, suggesting that possible domains for the interaction of NS4A were in those regions of the enzyme protein (NS3) and/or the substrate protein. Two proteins, p58 and p56, were produced from NS5A. For the production of p58, equal or excess molar amounts of NS4A relative to NS delta 4A were required. Deletion analysis of NS4A revealed a minimum functional domain of NS4A of 10 amino acids, from Gly-1678 to Ile-1687.

Amino Acid Sequence↗
PubMed1995

Phosphorylation of hepatitis C virus-encoded nonstructural protein NS5A.

Two proteins, a 56-kDa protein (p56) and a 58-kDa protein (p58), are produced from the hepatitis C virus (HCV) nonstructural region 5A (NS5A). Recently, we found that both proteins are phosphorylated at serine residues and that p58 is a hyperphosphorylated form of p56. Furthermore, hyper-phosphorylation depends on the production of an intact form of the HCV NS4A protein. To clarify the nature of NS5A phosphorylation, pulse-chase analysis was performed with a transient protein production system in cultured cells. The study indicated that basal and hyperphosphorylation of NS5A occurred after proteolytic production of NS5A was complete. In an attempt to identify the location of the hyperphosphorylation sites in p58, proteins with sequential deletions from the C-terminal region of NS5A and with mutations of possible phosphorylated serine residues to a neutral amino acid, alanine, were constructed. The deleted or mutated proteins were then tested for hyperphosphorylation in the presence of the NS4A product. Here, we report that serine residues 2197, 2201, and/or 2204 are important for hyper-phosphorylation. Important sites for basal phosphorylation were identified in the region from residues 2200 to 2250 and in the C-terminal region of the NS5A product. A subcellular localization study showed that most of the NS5A products were localized in the nuclear periplasmic membrane fraction.

Amino Acid Sequence↗
PubMed1995

The N-terminal region of hepatitis C virus nonstructural protein 3 (NS3) is essential for stable complex formation with NS4A.

Hepatitis C virus proteins are produced by proteolytic processing of the viral precursor polyprotein that is encoded in the largest open reading frame of the viral genome. Processing of the nonstructural viral polyprotein requires the viral serine-type proteinase present in nonstructural protein 3 (NS3). The cleavage of the junction between NS4B and NS5A is mediated by NS3 only when NS4A is present. NS4A is thought to be a cofactor that enhances the cleavage efficiency of NS3 in hepatitis C virus protein-producing cells. Stable NS3-NS4A complex formation required the N-terminal 22 amino acid residues of NS3. This interaction contributed to stabilization of the NS3 product as well as increased the efficiency of cleavage at the NS4B/5A site. The N-terminal 22 amino acid residues fused to Escherichia coli dihydrofolate reductase also formed a stable complex with NS4A. NS3 derivatives which lacked the N-terminal 22 amino acid residues showed drastically reduced cleavage activity at the NS4B/5A site even in the presence of NS4A. These data suggested that the interaction with NS4A through the 22 amino acid residues of NS3 is primarily important for the NS4A-dependent processing of the NS4B/5A site by NS3.

Base Sequence↗
PubMed1995

Quantitative immunoelectron microscopic analysis of the localization and induction of 25-hydroxyvitamin D3 24-hydroxylase in rat kidney.

25-Hydroxyvitamin D3 24(R)-hydroxylase (24-hydroxylase) is involved in the metabolism and regulation of vitamin D3 and is markedly induced by administration of vitamin D3. We detected this enzyme by electron microscopy and an immunogold technique along nephrons of normal and vitamin D3-administered rats. After the rats were administered vitamin D3, 50,000 IU/day for 1 week, they were perfusion-fixed with a paraformaldehyde solution. The fixed kidneys were then removed and embedded in LR White resin. Ultrathin sections were prepared and labeled by the immunogold technique using a mouse anti-rat 25-hydroxyvitamin D3 24-hydroxylase monoclonal antibody. We counted the number of gold particles bound per micron 2 of the mitochondria (particle density) of the tubule epithelial cells along the nephrons. In normal and vitamin D3-administered rats, gold particles were observed in the mitochondria of epithelial cells along the tubules. In normal rats, gold labeling for 24-hydroxylase was statistically significant (p < 0.05), in the S1-S2 segments, the S3 segment of the proximal tubules, and in the distal convoluted tubules. In the rats administered vitamin D3, the particle density increased significantly (p < 0.05) by about 12-fold in the S1-S2 segments of the proximal tubules, whereas it increased less markedly in other parts of the nephron. The marked induction of the S1-S2 segments of the proximal tubules suggests that these segments play an important role in the regulation of vitamin D3 metabolism.

Animals↗
PubMed1995

Quantitative cryoimmunogold electron microscopic studies on induction of serine: pyruvate aminotransferase in rat liver mitochondria by administration of glucagon.

Induction of mitochondrial serine: pyruvate aminotransferase (SPT) in rat liver by administration of glucagon was studied quantitatively by immunoblot analysis and cryoimmunogold electron microscopy. Immunoblot analysis revealed that two daily injections of glucagon produced marked increase of SPT protein mass to a level as much as 18 times that of the untreated rat. Cryoimmunogold electron microscopic analysis showed that the labeling density of the mitochondria increased in a parallel manner. Thus the induction of SPT analyzed by two methods showed an excellent correlation with a relative correlation coefficient of 0.98, indicating that the induction of SPT can be analyzed quantitatively by immunogold electron microscopy on cryoultrathin sections.

Animals↗