Search PubMed⌕ Search

Biomedical subjects

S Satoh

Publications and source records attributed to S Satoh.

At least 469 records · Page 26Linked to original sources
PubMed1994

[Cyclic thrombocytopenia associated with erythroid hypoplasia--a case].

We report the case of a 75-year-old woman with cyclic thrombocytopenia associated with erythroid hypoplasia. One platelet cycle lasted for about 28-30 days, with the platelet count fluctuating from 1.0 x 10(4)/microliter to 56.0 x 10(4)/microliter. Megakaryocyte count increased in the phase during which platelet count increased, and decreased in the phase during which platelet count decreased. Bone marrow colony formation was observed in serum-free agar, and megakaryocyte colony count was correlated with the platelet cycle. Platelet-associated immunoglobulin was in the normal range when platelet count increased, but increased when platelet count decreased. These findings suggest that the observed platelet count fluctuation was related to the production and destruction of platelet. Our patient also had erythroid hypoplasia, but her erythrocyte count did not fluctuate. This is the first reported case of cyclic thrombocytopenia and erythroid hypoplasia.

Aged↗
PubMed1994

Photopic electroretinogram implicit time in diabetic retinopathy.

Photopic electroretinograms (ERGs) elicited with red or white flashes of various intensities under a bright background light were recorded in 119 eyes of 77 diabetic patients and 19 normal control eyes. The implicit time and amplitude of photopic ERGs were analyzed in relation to the stage of diabetic retinopathy, ie, diabetic eyes without retinopathy, eyes with mild nonproliferative diabetic retinopathy (mild NPDR), moderate NPDR, preproliferative diabetic retinopathy (PPDR) and proliferative diabetic retinopathy (PDR). The implicit time was significantly delayed in eyes with moderate NPDR, PPDR and PDR relative to eyes with mild NPDR, eyes without retinopathy or normal eyes. The delay of implicit time significantly increased as the severity of retinopathy progressed from mild NPDR to PPDR. The amplitude was reduced in PPDR and PDR, while the correlation with the severity of retinopathy was not so significant as with the delay of implicit time. These findings suggest that the photopic ERG implicit time can be a good indicator for the objective evaluation of the severity of diabetic retinopathy ranging from mild NPDR to PPDR, where retinal laser photocoagulation should be considered.

Adult↗
PubMed1994

Identical blood pressure levels and slower heart rates among nurses during night work and day work.

To investigate the effects of shift work on circadian BP variation, ambulatory 24h BP monitoring was performed during the day shift and night shift on 17 normotensive nurses. On both shifts, BP and heart rate increased in the working phase and decreased during sleep. The mean 24h BP and heart rate were identical in the two shifts. During sleep, BP was lower and the heart rate was slower in the day shift (night sleep) perhaps because of deeper sleep than during daytime sleep associated with the night shift. During work, BP was identical but the heart rate was significantly slower during the night shift. These data suggest that the circadian BP variation is determined largely by the sleep-wakefulness cycle and that the heart rate is also influenced by the internal body clock.

Adult↗
PubMed1993

[Percutaneous transhepatic gastrostomy with CT guidance in patients with partial gastrectomy].

Percutaneous transhepatic gastrostomy was performed in two patients, one with partial gastrectomy and Billroth I anastomosis and one with esophageal reconstruction with subtotal stomach, in whom oral feeding was precluded. In both patients, percutaneous gastrostomy with fluoroscopic guidance was impossible since the gastric remnants were small, had a high subcostal position, and were overlain by the transverse colon, lung and left lobe of the liver. The only route available to avoid the overlying bowel and lung was the transhepatic approach. The gastric remnants were punctured with a 22-gauge PTC needle through the left lobe of the liver with CT guidance, and an 8 Fr. Cope-type catheter was fluoroscopically placed in the gastric remnant or the duodenum after tract dilatation over the guide wire. No complications occurred during or after the procedures, and the condition of both patients was greatly improved. Although gastrostomy in patients with partial gastrectomy is thought to be very difficult, percutaneous transhepatic gastrostomy with CT guidance is easy and may be safe since adhesion between the liver and gastric remnant can prevent massive hemorrhage or displacement of the catheters.

Aged↗
PubMed1993

Thrombospondin as an agglutinin of platelets.

To study a hypothesis that thrombospondin (TSP) might function as an agglutinin in platelet aggregation, we designed two experiments. First, we prepared fibrinogen-coated agarose beads (fbg-beads) as a model of platelets, and subjected them to aggregometry using TSP as an inducer. TSP induced agglutination of fbg-beads in a dose-dependent manner. Calcium (Ca) and Magnesium (Mg) were necessary for the agglutination, and the aggregability was dependent on the concentration of Ca. These results confirmed the function of TSP as an agglutinin, suggesting some characteristics of the fbg-TSP interaction as well. Secondly, a variety of platelets were subjected to TSP-induced aggregation assay. Both gel-filtrated and washed-platelets were aggregated by TSP in a dose dependent manner and dissociated with EDTA. The same aggregation was observed in formalin-fixed platelets. Both Ca and Mg were required for the aggregation, and the maximum aggregation rate was dependent on the Ca concentration. Ca seemed to regulate the capacity as well as the affinity of the binding sites for TSP on platelets. Fibrinogen and some aminosugars inhibited the aggregation. These data suggest TSP may function as an agglutinin of platelets, and Ca may regulate the interaction between platelets and TSP. As one of the candidates for the receptor for TSP on platelet, fbg-GPIIb/IIIa was suggested because of the similarity between fbg-beads and platelets aggregation induced by TSP, and the Ca-dependency in both the GPIIb/IIIa induction and the TSP-induced platelet aggregation.

Agglutinins↗
PubMed1993

Inhibition of internalization of glucose transporters and IGF-II receptors. Mechanism of action of MHC class I-derived peptides which augment the insulin response in rat adipose cells.

Peptides from the alpha 1 domain of the major histocompatibility complex class I antigen (MHC class I), e.g. Dk-(61-85) and Dk-(62-85), have been shown previously to augment glucose uptake in insulin-stimulated cells and to inhibit insulin receptor internalization (Stagsted, J., Reaven, G. M., Hansen, T., Goldstein, A., and Olsson, L. (1990) Cell 62, 297-307). We now report that these peptides inhibit by 80-100% the internalization of glucose transporters (GLUT4) and insulin-like growth factor II (IGF-II) receptors in insulin-stimulated cells and correspondingly double insulin-stimulated glucose transport activity and the number of GLUT4 and IGF-II receptors on the cell surface. In addition, the peptides enhance the apparent affinity about 3-fold of IGF-II binding to its receptor. It is concluded that the effects of the peptides on glucose transport and IGF-II binding are a consequence of the peptide-mediated inhibition of internalization of GLUT4 and IGF-II receptor. The active peptides are derived from the alpha 1 domain of a MHC class I molecule, suggesting that the latter is involved in regulation of internalization of cell surface integral membrane proteins such as the GLUT4 and IGF-II and insulin receptors.

3-O-Methylglucose↗
PubMed1993

Effects of nifedipine and TMB-8 on renal vasoconstriction induced by hypertonic saline in dogs.

Intrarenal arterial infusion of hypertonic saline (+30 mEq/l NaCl in renal plasma) reduced renal blood flow and glomerular filtration rate with little change in filtration fraction in anesthetized dogs. The blood flow and the filtration rate responses were suppressed during infusion of nifedipine (0.1 microgram/kg per min). TMB-8 (50 micrograms/kg per min) also suppressed the blood flow response but not the filtration rate response. These results suggest that preglomerular vasoconstriction during hypertonic saline infusion requires Ca2+ influx via voltage-dependent Ca2+ channels and that hypertonic saline slightly contracts postglomerular vessels by activating a TMB-8-sensitive Ca2+ movement pathway.

Animals↗
PubMed1993

Use of bismannose photolabel to elucidate insulin-regulated GLUT4 subcellular trafficking kinetics in rat adipose cells. Evidence that exocytosis is a critical site of hormone action.

The subcellular trafficking of tracer-tagged GLUT4 between the plasma membranes and low-density microsomes of rat adipose cells has been studied. Cell-surface GLUT4 have been initially tracer-tagged in the insulin-stimulated state with the [3H]bismanose photolabel 2-N-4-(1-azi-2,2,2-trifluoroethyl)benzoyl-1,3-bis-(D-mannos- 4-yloxy)-2- propylamine. The half-time for internalization of tracer-tagged GLUT4 when insulin is removed by collagenase treatment is similar to that observed for the decrease in immunodetectable GLUT4 in the plasma membranes and the decrease in glucose transport activity in the intact cells. In contrast, internalization of tracer-tagged GLUT4 also occurs when cells are maintained in the continuous presence of insulin even though the plasma membrane level of immunodetectable GLUT4 and glucose transport activity in the intact cells are unaltered. These data show, for the first time, that insulin has little, if any, effect on the rate constant for GLUT4 endocytosis, but instead, primarily increases the rate constant for exocytosis. Tracer-tagged GLUT4 that is returned to the low-density microsomes can be restimulated with fresh insulin to recycle to the plasma membranes and to a steady-state distribution level that is the same as that observed in cells that are maintained in the continuous presence of insulin. These data suggest that the cells' entire complement of GLUT4 is involved in the recycling process. Following insulin stimulation of adipose cells initially in the basal state, the increase in immunodetectable GLUT4 in the plasma membranes precedes the increase in accessibility of GLUT4 to exofacial 2-N-4-(1-azi-2,2,2-trifluoroethyl)benzoyl-1,3-bis(D-mannos-4 -yloxy)-2- propylamine photolabeling, and this in turn precedes the increase in cellular glucose transport activity. Such time course data suggest that there may be plasma membrane intermediate states in the GLUT4 trafficking pathway. The kinetic properties of GLUT4 translocation and its recycling have been interpreted in terms of a subcellular trafficking model that identifies exocytosis, possibly involving-hypothetical "docking" and "fusion" steps, as the critical site of hormone action.

3-O-Methylglucose↗
PubMed1993

Ras proteins increase Ca(2+)-responsiveness of smooth muscle contraction.

G-proteins may be involved in receptor-mediated Ca(2+)-sensitization of smooth muscle contraction, but the responsible G-proteins are not yet known. Here we show that in beta-escin skinned mesenteric microarteries, H-ras p21 proteins, preactivated with GTP or GTP gamma S, increase force at constant submaximal Ca2+ (pCa 6.3) concentration dependently. The GTP-bound form of the wild-type H-ras p21 and the oncogenic mutant (p21[G12V]) were equally effective. The nucleotide-free and the inactive GDP-bound form of ras p21 had no effect on force. The tryosine kinase inhibitor, tryphostin, partially reversed the effect of the ras proteins in the GTP-bound form on force. Thus, ras proteins mimic the Ca(2+)-sensitizing effect of GTP gamma S and vasoconstrictors in mesenteric microarteries which may involve tyrosine phosphorylation.

Animals↗
PubMed1993

Purification and molecular cloning of mouse renal dipeptidase.

Mouse renal dipeptidase (mouseRDP, EC 3.4.13.11) was purified from the membrane fraction of kidney. The molecular mass of the enzyme was 115 kDa by size-exclusion HPLC and SDS-PAGE under non-reduced conditions and 58 kDa by SDS-PAGE under reduced conditions. The mouseRDP cDNA fragment was amplified from mouse kidney total RNA by reverse transcription-polymerase ŏffin reaction (RT-PCR). The mouseRDP cDNA was isolated from a kidney cDNA library using the probe. The primary structure of mouseRDP deduced from the cDNA showed a high homology with renal dipeptidase from various mammals, except for the amino-terminal and carboxy-terminal domains. Recombinant mouseRDP obtained from transfected mouse L929 cells containing the expression plasmids has the same Km value and molecular mass as native mouse renal dipeptidase. From Northern blotting analysis, expression of the mouseRDP gene was recognized in both kidney and liver.

Amino Acid Sequence↗
PubMed1993

Cloning and structural analysis of genomic DNA for human renal dipeptidase.

A genomic DNA for human renal dipeptidase was isolated from a human genomic library using probes for human renal dipeptidase cDNA. The human renal dipeptidase gene, containing ten exons and nine introns, had a total length of approx. 6 kbp. The DNA sequence of these exons was slightly different from that of the human renal dipeptidase cDNA reported by Adachi et al. [1]. From the results of a comparison of the deduced amino acid sequence of each exon with various mammalian renal dipeptidases, the fourth exon was found to be highly conserved (90%).

Amino Acid Sequence↗
PubMed1993

Tyrosine kinase inhibitors suppress agonist-induced contraction in smooth muscle.

Because tyrosine kinases participate in diverse signalling pathways, we suspected that these enzymes might also participate in regulation of signal transduction in smooth muscle. Therefore, we studied the effects of geldanomycin, tyrphostin, and genistein, three structurally unrelated tyrosine kinase inhibitors, on receptor-mediated and depolarization-mediated contraction in three different types of smooth muscle. Contraction elicited by stimulation of muscarinic receptors with carbachol, or by stimulation of alpha-adrenergic receptors with norepinephrine or phenylephrine were markedly (> 80%) and reversibly inhibited by tyrosine-kinase inhibitors. In contrast, only slight inhibition (20%) occurred in contractions elicited by K(+)-induced depolorization. Moreover, tyrphostin did not inhibit direct Ca(2+)-mediated activation of the contractile apparatus in preparations permeabilized with beta-escin. These results suggest the novel hypothesis that tyrosine kinases participate in regulation of signal transduction that is associated with receptor-mediated contraction of smooth muscle.

Animals↗
PubMed1993

Insulinomimetic effect on glucose transport by epidermal growth factor when combined with a major histocompatibility complex class I-derived peptide.

Peptides derived from the alpha 1-region of the murine H-2Dk molecule enhance glucose uptake in rat adipose cells above the maximum obtained with insulin stimulation alone (Stagsted, J., Reaven, G. M., Hansen, T., Goldstein, A., and Olsson, L. (1990) Cell 62, 297-307). We now describe that epidermal growth factor (EGF) in combination with the same peptides, Dk-(61-85) and Dk-(62-85), stimulates cellular glucose uptake 5-7 times over the basal level, i.e. to 30-50% of the maximal insulin effect. EGF alone increased glucose uptake by only approximately 50% above basal and the peptide alone by 100% above basal. Maximal effect of EGF and peptide was reached in 10-20 min with 30 microM peptide (EC50 10-15 microM) and 50 nM EGF (EC50 1-2 nM). The effect of EGF and peptide on glucose uptake was additive to that of insulin and peptide until the maximal level attained with insulin and peptide was reached. The combined effect of EGF plus peptide on glucose transport was associated with a recruitment of GLUT4 molecules to the plasma membrane. However, the phosphatidylinositol (PI) kinase which is activated by insulin was not activated by EGF plus peptide. Thus, the effect of EGF plus peptide on glucose uptake seems independent of the activity status of the insulin receptor. 125I-Labeled EGF bound specifically to rat adipose cells with an apparent affinity of approximately 2 nM and Bmax approximately 5 x 10(3). However, the major histocompatibility complex (MHC) peptides did not affect EGF-stimulated internalization of EGF receptor, in contrast to their effect on the insulin receptors. Transforming growth factor alpha had an effect similar to EGF on glucose uptake. Three other peptides derived from other parts of murine MHC class I had no effect on glucose uptake in combination with EGF. Thus, EGF in combination with certain MHC class I-derived peptides is insulinomimetic concerning glucose transport and this effect is independent of the insulin receptor activity.

3-O-Methylglucose↗
PubMed1993

Renal effects of manidipine hydrochloride. A new calcium antagonist in hypertensive patients.

The renal effects of manidipine hydrochloride were investigated in ten hospitalised patients with mild-to-moderate essential hypertension. After a one-week placebo period, manidipine was given for 1 week in a dose rising from 5 mg to 10 mg or 20 mg daily to normalise the mean blood pressure measured after 2 h. Blood pressure had decreased from 171/101 to 147/86 mm Hg at the end of manidipine treatment. The pulse rate was unaltered. Renal vascular resistance decreased from 1.90 to 1.33 dyn.s.cm-5/1.48 m2 x 10(4), and renal blood flow and glomerular filtration rate increased from 522 to 662 ml.min-1 x 1.48 m-2 and from 81 to 93 ml.min-1 x 1.48 m-2, respectively, in spite of a fall in renal perfusion pressure. Manidipine reduced the filtration fraction from 0.260 to 0.243, suggesting a preferential reduction in efferent arteriolar resistance. The fractional excretion of sodium and potassium did not change. Manidipine did not produce any significant alteration in plasma renin activity or in the plasma aldosterone concentration. The results indicate that manidipine has favourable renal effects and a concomitant hypotensive action in patients with mild-to-moderate essential hypertension.

Adult↗
PubMed1993

Early and delayed SPECT images of extracerebral fluid collection in infants using 123I-N-isopropyl-p-iodoamphetamine.

Cerebral blood flow in seven infants with extracerebral fluid collections was investigated using single photon emission computed tomography (SPECT) with 123I-N-isopropyl-p-iodoamphetamine. Early and delayed SPECT imaging was carried out. Areas of hypoperfusion were observed in five cases. The watershed zone of the major cerebral arteries or the territory of the anterior cerebral arteries were common areas of low perfusion. The hypoperfusion area was redistributed in two cases with intracranial hypertension. Subduroperitoneal shunts produced improvement of clinical symptoms in these cases. Hypoperfusion without redistribution was observed in three patients. In these areas, permanent tissue damage caused by a primary disease existed. Normal circulation patterns were observed in two patients. They showed normal development and follow-up CT revealed a decrease in the size of the extracerebral fluid collection. Measurement of regional cerebral blood flow may be helpful in considering surgical indications and in following up extracerebral fluid collection in infants.

Asphyxia Neonatorum↗
PubMed1993

A case of schizophrenia with a dicentric Y chromosome.

A case of DSM-III-R schizophrenia with a dicentric Y chromosome (46,X,dic(Y)(q11)) is reported. Structural chromosome abnormalities such as this case may provide clues to finding regions of the genome etiologically involved in schizophrenia.

Chromosome Banding↗
PubMed1993

Autologous vein supported with a biodegradable prosthesis for arterial grafting.

To evaluate the potential of a supporting, compliant, biodegradable prosthesis to function as a temporary protective scaffold for autologous vein grafts in the arterial circulation, we implanted vein grafts into the carotid arteries of rabbits, either with (composite grafts) or without (control grafts) such a supporting prosthesis, and evaluated them up to 6 weeks. The control vein grafts showed edema and severe medial disruption with infiltration of polymorphonuclear cells on day 1. Over the study, irregular fibrocyte formation resulted in the formation of a fibrotic vein wall. In contrast, the composite vein grafts showed preservation of smooth muscle cell layers and elastic laminae with a minor inflammatory response. Regular proliferation of fibroblasts, which in some areas were circularly oriented, was observed. We conclude that a supporting, compliant, biodegradable prosthesis can function as a protective scaffold for vein grafts in the arterial circulation, thus reducing damage to the vein graft wall and allowing gradual arterialization.

Animals↗