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Biomedical subjects

Y Satoh

Publications and source records attributed to Y Satoh.

At least 253 records · Page 14Linked to original sources
PubMed1995

Physical and gene organization of mitochondrial DNA from the fertile cytoplasm of sugarbeet (Beta vulgaris L.).

We have constructed a complete physical map of the mitochondrial genome from the male-fertile cytoplasm of sugarbeet. The entire sequence complexity can be represented on a single circular master chromosome of 358 kb. This master chromosome contains three copies of one recombinationally active repeat sequence, with two copies in direct orientation and the other in inverted orientation. The positions of the rRNA genes and of 23 polypeptide genes, determined by filter hybridization, are scattered throughout the genome, with triplicate rrn26 genes located partially or entirely within the recombination-repeat elements. Three ribosomal-protein genes (rps1A, rps14 and rps19) were found to be absent from sugarbeet mtDNA. Our results also reveal that at least six regions homologous with cDNA are dispersed in the mitochondrial genome.

Chromosome Mapping↗
PubMed1995

G-protein activation enhances Ca(2+)-dependent lipid secretion of the rat harderian gland.

We studied the secretory mechanism of the Harderian gland of rats. After perfusion with HEPES-buffered Ringer's solution containing NaF (10 mM) with AlCl3 (10 microM), a G-protein activator, the glandular cells of the Harderian gland showed massive exocytosis and apocrine-like protrusions on the luminal surface. Some of the secretory vacuoles aggregated within the cytoplasm, and large vacuoles were formed. Contraction of the myoepithelial cells covering the glandular endpieces caused a narrowing of the glandular lumina, which contained cytoplasmic fragments, and deformation of the basal contour of the glandular end-pieces. The basal regions of the glandular cells also bulged between the myoepithelial cells. Secretory vacuoles were also discharged to the lateral cell surface, and the intercellular spaces were dilated. The enhanced secretory activities of the glandular cells and the contraction of the myoepithelial cells were similar to those in rats stimulated with 10 microM carbachol (CCh). However, dilatation of the endoplasmic reticulum in glandular cells (type A cells), which leads to the formation of small vesicles, was observed in those glands stimulated by NaF+AlCl3, but not in those stimulated by CCh. Removal of Ca2+ from the perfusing HR or addition of EDTA (0.5 mM) diminished and inhibited NaF+AlCl3- or CCh-enhanced secretory activity of the glandular cells and also allayed the deformation of glandular cells caused by myoepithelial cell contraction. The present results demonstrate the involvement of G-proteins and Ca(2+)-influx in the lipid secretion of glandular cells and in the contraction of myoepithelial cells of the Harderian gland in rats.

Aluminum Chloride↗
PubMed1995

Carbamylcholine- and catecholamine-induced intracellular calcium dynamics of epithelial cells in mouse ileal crypts.

BACKGROUND/AIMS: The intestinal epithelium is composed of various cells, and the enteric nervous system, which controls the epithelial functions, has different neurotransmitters and/or modulators. The aim of this study was to show whether the responses of intestinal epithelial cells to different neurotransmitters are elicited throughout the entire epithelium or are restricted to a certain cell. METHODS: The spatiotemporal dynamics of cytosolic calcium ion ([Ca2+]c) were measured by digital imaging analysis in isolated crypts of mouse ileum loaded with [1-[2-(5'-carboxyoxazol-2'-yl)-6-amino-benzofuran-5- oxy]-2-(2'-amino-5'-methylphenoxy)-ethane-N,N,N',N'-tetraacetic acid] pentakis (acetoxylmethyl) ester. Thereafter, the crypt cells were identified morphologically. RESULTS: Carbamylcholine elicited [Ca2+]c dynamics in Paneth cells, showing a biphasic increase, but neither cholecystokinin octapeptide nor nicotine had any effect on the [Ca2+]c of the crypt cells including the Paneth cells. Adrenaline and noradrenaline, but not isoproterenol, induced a transient elevation of [Ca2+]c of some enterochromaffin cells. Increases in the [Ca2+]c of most crypt cells were elicited by thapsigargin. Propagation of a [Ca2+]c wave in the crypts was not evident. CONCLUSIONS: Increases in [Ca2+]c can be induced by carbamylcholine in Paneth cells and catecholamines in some enterochromaffin cells. The digital imaging analysis showed the heterogeneity of the responses of intestinal crypt cells to different transmitters.

Animals↗
PubMed1995

Extrapancreatic effects of sulfonylureas--a comparison between glimepiride and conventional sulfonylureas.

The contribution of extrapancreatic effects of sulfonylureas to the blood glucose-decreasing activity was reevaluated in vivo and in vitro with several conventional sulfonylureas and with the new one glimepiride. In vivo, in dogs, after single approximately equipotent blood glucose-decreasing doses, the sulfonylureas were tested for a ranking in the ratios of mean plasma insulin-increasing and blood glucose-decreasing activity. Studies were also performed in hyperglycemic hyperinsulinemic KK-Ay mice under once daily treatment for 8 weeks. In vitro, glimepiride and glibenclamide were tested for the ranking of their extrapancreatic activity with respect to the stimulation of glucose transport and glucose metabolizing processes in normal and insulin-resistant fat cells as well as in the isolated diaphragm. Furthermore, in vitro studies were performed, especially with glimepiride, in order to characterize the molecular mechanism for the extrapancreatic activity. The dog studies revealed a marked ranking in the ratios of plasma insulin-increasing and blood glucose-decreasing activity between the different sulfonylureas (glimepiride < glipizide < gliclazide < glibenclamide). In the hyperglycemic hyperinsulinemic KK-Ay mice, glimepiride reduced blood glucose by 40%, plasma insulin by 50% and HBA1c by 33%, whereas glibenclamide and gliclazide had no effect on these parameters. In vitro, glimepiride and glibenclamide had extrapancreatic effects within the lower microM range, with glimepiride exhibiting 2-3-fold lower ED50 values than glibenclamide. In the absence of insulin, both stimulated glucose transport--up to 60% of the maximum insulin response in the rat diaphragm and up to 35% in 3T3 adipocytes. Glycogenesis was stimulated in the rat diaphragm--up to 55% of the maximum insulin effect; lipogenesis in 3T3 adipocytes--up to 40%. The studies on the molecular mechanism of extrapancreatic activity with rat adipocytes and diaphragm suggest that these direct insulin-mimetic effects rely on the induction of GLUT4 translocation from internal stores to the plasma membrane and on the activation of the key metabolic enzymes, glycogen synthase and glycerol-3-phosphate acyltransferase. These processes occur within the same drug concentration range and with the same ranking between glimepiride and glibenclamide as observed for glucose utilization and transport. The direct effects of sulfonylureas may ultimately be regulated by a glycosyl-phosphatidylinositol-specific phospholipase C, shown to be activated by glimepiride in rat adipocytes. Lipolytic cleavage products thereby generated from glycolipidic structures may in turn stimulate specific protein phosphatases which activate key regulatory proteins/enzymes of glucose and lipid metabolism.(ABSTRACT TRUNCATED AT 400 WORDS)

Adipocytes↗
PubMed1995

Ultrasound-guided microwave thermotherapy on a VX-2 carcinoma implanted in rabbit kidney.

A temperature greater than 60 degrees C was maintained for 60 s within a 5-mm radius of a microwave electrode implanted in a rabbit kidney using 2450 MHz at 100 W for 30 s. Histological examination revealed complete coagulation necrosis in that area. VX-2 cells were inoculated into the kidneys of 10 rabbits. One week later, five rabbits received ultrasound-guided microwave thermotherapy, and the remaining five rabbits received no treatment. All rabbits with microwave thermotherapy had a complete response to treatment while all rabbits without therapy died of cancer within 6 weeks of the VX-2 implantation. These results indicate that ultrasound-guided microwave thermotherapy has the potential of being a nephron-salvaging treatment for small renal tumors.

Animals↗
PubMed1995

Pharmacokinetics and biologic activities of human native and asialointerferon-beta s.

Glycoproteins are metabolized through an asialoglycoprotein metabolic pathway in vivo. They are desialylated and taken up by the liver via an asialoglycoprotein receptor. Fibroblast-derived natural human interferon-beta is a glycoprotein having a single asparagine-linked sugar chain. Although natural human interferon-beta may also be metabolized through this pathway, there is very little information about the biologic features of human asialointerferon-beta. We evaluated the pharmacokinetics and biologic activities of human native and asialointerferon-beta s. After intravenous administration to rabbits, human asialointerferon-beta was cleared from the blood circulation faster than the human native interferon-beta. More asialoprotein was distributed to the liver than the native type, but it induced less 2'5'-oligoadenylate synthetase. The human asialointerferon-beta had less activity than the human native interferon-beta on cell growth inhibition and 2'5'-oligoadenylate synthetase induction in Hep-G2 and HuH6 human hepatoblastoma cells. Southern blotting using a hepatitis B virus-transfected HuH6 cell line, HB611, revealed that the inhibition of hepatitis B virus DNA replication by the asialoprotein was weaker than that by the native protein. The results showed that the different effects exerted by the human native and asialointerferon-beta s may be a result of recognition of the sugar chains by rabbit hepatocytes or by human hepatoblastoma cells. The results also suggested that the terminal sialic acid of the sugar chains in natural human interferon-beta significantly affects its pharmacokinetics and biologic activities.

2',5'-Oligoadenylate Synthetase↗
PubMed1995

Carbohydrate-dependent biological activities of glycosylated human interferon-beta on human hepatoblastoma cells in vitro.

To evaluate the relationship between the sugar chain structure and biological activity, fibroblast-derived glycosylated human interferon-beta, Chinese hamster ovary cell-derived glycosylated recombinant human interferon-beta and Escherichia coli-derived unglycosylated recombinant human interferon-beta were evaluated using human hepatoblastoma cells in vitro. Native fibroblast interferon-beta expressed more cell-growth inhibitory action, 2'5'-oligoadenylate synthetase induction, and the inhibition of hepatitis B virus DNA replication than its asialoform and two recombinant interferon-betas. These results showed that the sugar chain structure of human interferon-beta affects its biological activity on human hepatoblastoma cells.

2',5'-Oligoadenylate Synthetase↗
PubMed1995

Alterations of expression of the cytoskeleton after immortalization of human fibroblasts.

Human diploid fibroblasts (HDF) have a limited in vitro lifespan of population doubling level (PDL) 50-70. The molecular mechanism underlying cellular senescence and immortalization is not thoroughly understood. It has been reported that the cytoskeleton has diverse functions and may have a role in growth regulation through association with other cellular components. To shed light on the relationship between functions of the cytoskeleton and senescence or immortalization, we investigated the alterations in gene expression after immortalization and measured the amounts of mRNAs for talin, vinculin, alpha-actinin, tropomyosin 1 (TM1), vimentin, lamin A and C, and alpha-tubulin by slot blot and Northern blot analyses. We found that the mRNAs for vinculin and vimentin were reduced and the mRNA for lamin A was increased in immortalized cells. We also studied the cytoskeletal protein levels and their intracellular distributions by Western blot analysis and immunostaining. Most of the proteins studied behaved in a way similar to the mRNAs through senescence and immortalization. Vinculin, tropomyosins and vimentin showed their altered distributions in immortalized cells.

Cell Line↗
PubMed1995

Isolation of some immunosuppressive components from an ascomycete, Gelasinospora multiforis.

Five new components, named multiforisins A, B, C, D, and E, with immunosuppressive activity were isolated from an Ascomycete, Gelasinospora multiforis. Multiforisin A, the main immunosuppressive principle of this fungus, was deduced to be 5-formyl-3-(hydroxymethyl)-4-methoxy-6-(1E-propenyl)-alpha-pyrone. Multiforisins B, C, D, and E were also deduced to be alpha-pyrone derivatives related to multiforisin A. The IC50 values of multiforisins A, B, C, D, E, and dihydro multiforisin A were evaluated against proliferation of mouse spleen lymphocytes stimulated with concanavalin A and lipopolysaccharide.

Ascomycota↗
PubMed1995

Relaxation effect of an audiovisual system on dental patients. Part 2. Palus-amplitude.

Dental care services include relaxation of patients to reduce their displeasure at and tension during treatment. For this purpose, it is common to use audio or audiovisual programs, that is, to let them listen to music or watch TV. However, the former utilizes only the auditory sense, and the latter is disadvantageous in that a TV set is a rather large-scale unit. In the present study, we determined the relaxation effect of an audiovisual instrument on dental patients. The instrument, which gives virtual vision, was composed of a lightweight eyeset of the snow goggle type that has a built-in TV screen, with earphone and accessories. The relaxation effect was determined using a polygraph.

Adult↗
PubMed1995

[Clinical evaluation of myasthenia gravis in elderly patients].

In Japan, elderly patients who develop myasthenia gravis (MG) are increasing in number. However, there are few clinical reports concerning this issue. We evaluated the clinical manifestations, inducing or exacerbating factors, complications, treatments and prognosis of systemic MG in 11 patients older than 60 years of age. Bulbar symptoms were more frequent in these patients compared with younger MG patients, and 6 out of 11 cases (54.5%) were mistakenly diagnosed as cerebrovascular disorders. Among inducing or exacerbating factors of MG were psychological problems inherently involved with the aged, physical factors, and inappropriate termination or rejection of medication. Increase in the level of anti-Ach-R antibodies was recognized in 10 out of 11 cases (90.9%). A high percentage of the patients had thymoma (36.4%) and thyroid diseases (45.5%): 3 with Hashimoto's thyroiditis (27.3%), 1 with thyroid ophthalmopathy associated with hyperthyroidism, and 1 with simple goiter. Others were accompanied by ischemic heart disease, prostatic hypertrophy or stomach cancer. We treated these patients with corticosteroids, immunoglobulin, radiation for thymoma, or thymectomy in addition to administration of anticholinesterase agents. Prognostically, we found that duration of illness before death was shorter in those with onset later than 70 years of age. Seven out of 11 (63.6%) patients died of either aspiration pneumonia (4 cases), complications of thymectomy, congestive pulmonary edema or stomach cancer. There were no deaths associated with myasthenic crisis.

Aged↗
PubMed1995

[Free rectus abdominis muscle perforating artery flaps for reconstruction of the head and neck defects].

During the past eight years, tissue defects of the head and neck region in a total of 45 patients were repaired with free rectus abdominis muscle perforating artery flaps. These flaps are subclassified into (1) reduced musculocutaneous flaps, (2) thin reduced musculocutaneous flaps, (3) paraumbilical perforator-based flaps, and (4) thin paraumbilical perforator-based flaps. The advantages of these flaps are as follows. Since the flaps involve no or only a small portion of the rectus abdominis muscle, (1) the muscle can be left intact on the abdominal wall, and (2) a thin flap can be easily created by simple defatting of the flap. These flaps overcome the major disadvantages of the conventional rectus abdominis musculocutaneous flap, i.e., bulkiness of the flap and frequent postoperative abdominal herniation. The territory of the thin flaps is within 10 cm around the perforator. These flaps are suitable for defects in the head and neck region, because simultaneous flap elevation is possible at the time of tumor resection. Paraumbilical perforator-based flaps are suitable for young females and elderly patients.

Aged↗
PubMed1995

[The preventive effect of indeloxazine hydrochloride to the sexual dysfunction caused by anti-androgenergic agent (allylestrenol)].

Anti-androgenergic agents are usually used for patients with benign prostatic hypertrophy (BPH). However steroidal anti-androgenergic agents tend to suppress the sexual function. This side effect is very significant in middle-aged men. Therefore we studied the preventive effect of indeloxazine hydrochloride (INDX), which induces an increase of the dopamine level in the brain, on the sexual dysfunction induced by an anti-androgenergic agent (allylestrenol: ALE). Thirty-six patients with BPH were classified into two groups, one used ALE only, and the other ALE with INDX. For the subjective evaluation of the sexual function, a self assessment questionnaire method was employed before and after administration. We especially studied 3 questions, "morning erection", "erectile capacity" and "frequency of sex". For the objective evaluation of the sexual function, nocturnal penile tumescence (NPT) was measured using an erectometer. NPT occurs in healthy males as a physiological phenomenon and it shows the erectile capacity objectively. The levels of LH, total testosterone and free testosterone were also determined. In the ALE only group, sexual dysfunction was found subjectively and objectively, but in the ALE with INDX group, it was not found. Levels of LH, total testosterone and free testosterone were decreased in the both groups. There was no significant difference between the two groups. We hypothesized that the sexual dysfunction due to ALE is related with not only to the decrease of androgen, but also to suppression of the central nervous system; for example, the suppression of the area of the brain mediating sexual behavior.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1995

[Pelvioureteral function after ureterotomy--experimental study simulating endopyeloureterotomy].

BACKGROUND: Endopyeloureterotomy has been established as a valuable procedure for ureteropelvic junction or upper ureteral stenosis. In order to evaluate ureteropelvic function after endopyeloureterotomy, I examined electromyographic change in ureteral peristalsis, measured urine bolue volume, and monitored ureteral compliance in dogs following ureterotomy. METHODS: Twelve adult mongrel dogs were anesthetized with pentobarbital, and the upper part of the left ureters was incised longitudinally for a distance of 2 cm. After the incision of the left ureter, a polyurethane splint was inserted through the kidney to the lower part of the ureter and left for four weeks. At 5 (n = 4), 12 (n = 4), and 24 (n = 4) weeks after the operation, electromyography in ureteral peristalsis, urine bolue volume, and ureteral compliance at the incised part of the ureter were investigated. During the measurement of peristaltic frequency and urine bolus volume, saline was infused to the renal pelvis at a constant rate through a nephrostomy. I also investigated these factors in 4 dogs without ureterotomy and defined this group as control. RESULTS: When the infusion rate increased, ureteral peristaltic frequency and/or urine bolus volume gradually increased in the groups of 12, 24 weeks and control group after the operation; in the group of 5 weeks, ureteral peristaltic frequency and bolus volume had not increased significantly. Peristaltic velocity at the incised area decreased significantly at 5 weeks and 12 weeks following the operation compared to the velocity in the control group, but recovered at 24 weeks. Ureteral compliance decreased significantly at 5 weeks compared to that in the incised area of control dog ureter, but increased gradually and recovered at 12 weeks. In the incised ureter the defect was healed with granulation tissue within 5 weeks, and covered by smooth muscle within 12 weeks. CONCLUSION: These results indicate that ureterotomy had harmful effects on ureteral peristalsis 5 weeks following surgery, but that ureteral function generally returned at 12 weeks, and recovered completely at 24 weeks. It was supposed that endopyeloureterotomy would improve ureteral function in patients with ureteropelvic junction and upper ureteral stenosis.

Animals↗
PubMed1995

Spurious hyperfixation of hexamethylpropyleneamine oxime in acute embolic stroke.

A 71-year-old man with atrial fibrillation suddenly had an embolism in the right middle cerebral artery. Single-photon emission CT was performed 4 hours after the onset of stroke and revealed markedly elevated 99mTc-hexamethylpropyleneamine oxime (HMPAO) uptake in the right frontotemporoparietal region. This area of HMPAO hyperfixation corresponded to the area of infarction, as determined by CT and MR. Our findings showed that HMPAO single-photon emission CT overestimated reflow hyperemia after reperfusion in the acute stage of embolic stroke, as it does in the subacute stage.

Acute Disease↗