Search PubMed⌕ Search

Biomedical subjects

K Satoh

Publications and source records attributed to K Satoh.

At least 703 records · Page 39Linked to original sources
PubMed1993

Age-related changes in the microvessels of the human stomach: an ultrastructural study.

The ultrastructure of microvessels in the gastric mucosa of patients with atrophic gastritis was investigated. In the gastric mucosa of atrophic gastritis, the endothelial cells of microvessels were irregularly swollen and subendothelial spaces were enlarged. The basement membrane underlying the endothelium was thickened. Degeneration of smooth-muscle cells was also evident in the media. These changes appear to correspond to sclerosis or aging of the microvessels. Such sclerotic changes in microvessels may initiate deterioration of the microenvironment in the gastric mucosa and may consequently affect metabolic activity of the gastric mucosal cells. Those sequences might induce degeneration or abnormal differentiation of mucosal cells. Such vascular changes may advance slowly and increase in intensity with advancing age. The final result would be the histologic changes associated with atrophic gastritis.

Aged↗
PubMed1993

Cardiovascular profile of Ro 40-5967, a new nondihydropyridine calcium antagonist, delineated in isolated, blood-perfused dog hearts.

Coronary and cardiac effects of Ro 40-5967 were compared in isolated, blood-perfused dog heart preparations. Intraarterial Ro 40-5967 increased blood flow in all preparations. In sinoatrial preparations, Ro 40-5967 decreased sinus rate and produced atrial stand-still when administered at high doses. In paced atrioventricular (AV) node preparations, Ro 40-5967 injected into the posterior septal artery (which perfuses the AV node) increased AV conduction time and at high doses produced second- or third-degree AV block. In the same preparations, Ro 40-5967 had little effect on AV conduction time, even at higher doses, when injected into the anterior septal artery (which perfuses the His-Purkinje ventricular system). In paced papillary muscle preparations, Ro 40-5967 reduced the force of contraction only at high doses. In spontaneously beating papillary muscle preparations, Ro 40-5967 decreased the force of contraction only at high doses and had no effect on the rate of automaticity even at higher doses. The dose that doubled blood flow was about one-fifth of the dose that produced a 15% decrease in sinus rate and also one-fifth of the dose that produced a 15% increase in AV conduction time. The dose that reduced the force of contraction by half was > 10 times the dose that doubled blood flow. The results indicate that the cardiovascular profile of Ro 40-5967 differs from those of verapamil and diltiazem but instead resembles that of dihydropyridine derivatives, which are classified as vasoselective calcium antagonists.

Animals↗
PubMed1993

Influences of pravastatin and simvastatin, HMG-CoA reductase inhibitors, on myocardial stunning in dogs.

We examined the effects of pravastatin and simvastatin, HMG-CoA reductase inhibitors, on stunned myocardium in vivo. Pravastatin and simvastatin were given orally 2 mg/kg for 3 weeks. After 3 weeks of administration, pentobarbital-anesthetized dogs were subjected to 15-min left anterior descending (LAD) coronary artery occlusion followed by 2-h reperfusion. Myocardial segment function was determined by sonomicrometry. The tissue energy and carbohydrate metabolites were determined in the 2-h-reperfused hearts. Administration of pravastatin and simvastatin for 3 weeks decreased serum cholesterol level and blood pressure (BP). Simvastatin resulted in a worsening of segment shortening in the reperfused myocardium as compared with control and pravastatin groups. The level of ATP in the simvastatin group was significantly lower as compared with that in the control group. The other metabolite levels were not significantly altered by either pravastatin or simvastatin. These results suggest that simvastatin enhances stunning of the myocardium in association with ATP reduction after reperfusion subsequent to ischemia.

Adenosine Triphosphate↗
PubMed1993

Limitation of stunning in dog myocardium by nucleoside and nucleotide mixture, OG-VI.

BACKGROUND: OG-VI is a nucleoside-nucleotide solution composed of 30 mM inosine, 30 mM cytidine, 30 mM sodium 5'-guanylate, 22.5 mM uridine, and 7.4 mM thymidine. It is expected to enhance the efficacy of intravenous hyperalimentation in surgically stressed patients. One of the main causes of ischemic myocardial damage is loss of adenine nucleotides from heart cells. The aim of the present study, therefore, was to examine the effect of OG-VI on myocardial mechanical function and energy metabolism in stunned myocardium. METHODS: Pentobarbital-anesthetized dogs were subjected to 20 min ligation of the left anterior descending (LAD) coronary artery, followed by reperfusion for 30 min. OG-VI at 0.1 or 0.2 ml/kg/min or saline was infused from the left femoral vein throughout the experiment. The tissue levels of high-energy phosphates in the hearts were determined after 30 min reperfusion. RESULTS: LAD flow, first derivative of left ventricular pressure (LVdp/dt), and segment function were increased by OG-VI in a dose-dependent manner. OG-VI infusion resulted in a significant improvement in LVdP/dt and segment shortening in the ischemic/reperfused myocardium compared with saline infusion. The levels of segment shortening with saline, 0.1, and 0.2 ml/kg/min OG-VI after reperfusion for 30 min were -0.3, 75, and 82% of the preligation levels, respectively. The tissue level of adenosine triphosphate (ATP) after reperfusion in OG-VI-infused animals was significantly higher than that in saline-infused animals. CONCLUSION: OG-VI has a positive inotropic action, and its infusion results in a marked cardioprotective effect in stunned myocardium associated with the restoration of tissue ATP level.

Animals↗
PubMed1993

Functional brain imaging of a catatonic type of schizophrenia: PET and SPECT studies.

A brain imaging study was conducted in the case of a catatonic type of schizophrenia (DSM-IIIR) by applying (i) positron emission tomography (PET) and (ii) single photon emission computed tomography (SPECT). A PET study using [18F]-2-fluoro-2-deoxy-D-glucose revealed a lower glucose utilization in the dorsal frontal and parietal lobes of both cerebral hemispheres. Correlative SPECT studies using [123I]-iodoamphetamine showed a diminished regional cerebral blood flow in similar regions of the cerebral hemisphere. A three-dimensional volume rendering method of the SPECT images (TITAN) identified the dorsal region of the fronto-parietal lobe as the most severely affected region. These patterns of deficits implicated the role of the dorsal frontal and parietal lobes in the pathogenesis of catatonic syndromes.

Activities of Daily Living↗
PubMed1993

Platelet-activating factor acetylhydrolase in red cell membranes. Does decreased activity impair erythrocyte deformability in ischemic stroke patients?

BACKGROUND AND PURPOSE: Platelet-activating factor acetylhydrolase hydrolyzes platelet-activating factor (1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine). It also hydrolyzes oxidized derivatives of phosphatidylcholine that have a short-chain acyl residue at the sn-2 position. This enzyme may act mainly in the degradation of oxidized phospholipids and may play a role in maintaining erythrocyte deformability. Therefore, we assessed the activity of red cell membrane platelet-activating factor acetylhydrolase in patients with ischemic stroke and studied the relation of the enzyme activity to red cell deformability. METHODS: Enzyme activity was measured in the detergent extract of red cell membranes from 38 patients with cerebral thrombosis and 38 age-matched healthy volunteers. Red cell filterability, an index of red cell deformability, was also measured. RESULTS: The enzyme activity in patients and control subjects was 100 +/- 74 and 148 +/- 128 nmol/g protein per minute (2.68 +/- 2.11 and 3.79 +/- 2.46 pmol/10(9) cells per minute) (mean +/- SD), respectively, and the difference was significant (p < 0.05 by the Mann-Whitney U test, two-sided test). Enzyme activity was correlated positively with red cell filterability in the patients (n = 20, r = 0.565, p < 0.01). CONCLUSIONS: Red blood cells from stroke patients have lower levels of platelet-activating factor acetylhydrolase activity when compared with those from healthy subjects. This may result in the accumulation of oxidized lipids in the cell membrane and lead to impaired red cell deformability in patients with cerebral thrombosis.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗
PubMed1993

Low shear stress can initiate von Willebrand factor-dependent platelet aggregation in patients with type IIB and platelet-type von Willebrand disease.

Platelets exposed to shear stress aggregate in the absence of exogenously added agonists, utilizing distinct platelet membrane receptors and ligands depending upon the level of shear stress applied. Using a modified cone and plate type viscometer, we previously demonstrated that, under low shear stress (18 dyn/cm2), aggregation is mediated by platelet membrane glycoprotein (GP) IIb-IIIa and fibrinogen, whereas aggregation induced by high shear stress (108 dyn/cm2) requires the binding of von Willebrand factor (vWF) to both GPIb-IX and GPIIb-IIIa (Ikeda, Y., M. Handa, K. Kawano, T. Kamata, M. Murata, Y. Araki, H. Anbo, Y. Kawai, K. Watanabe, I. Itagaki, et al. 1991. J. Clin. Invest. 87:1234-1240). Here we report that vWF-dependent aggregation occurs under low shear stress in citrated platelet-rich plasma (PRP) from two types of congenital bleeding disorders, platelet-type von Willebrand disease (vWD) and type IIB vWD, in both of which ristocetin-induced aggregation is known to be heightened. Aggregation induced by low shear stress was enhanced in both types of disorders compared to normal controls, and the enhancement was completely abolished by anti-vWF monoclonal antibody NMC-4, which blocks the GPIb-binding site on vWF. Under high shear stress, the extent of maximal aggregation was not different between controls and the patient groups although maximal aggregation was reached much more quickly in the latter. When citrated PRP was exposed to a gradient of shear stress (6 to 108 dyn/cm2 over a 5-min period), vWF-dependent aggregation, as judged from the inhibitory effect of NMC-4, first occurred at 14 dyn/cm2 in platelet-type vWD and at 10-12 dyn/cm2 in type IIB vWD, as compared with more than 81 +/- 20.1 dyn/cm2 in control platelets. These results suggest that an abnormality in either vWF or GPIb-IX triggers the aggregation-inducing interaction of the two molecules under low shear stress, which might explain the intravascular platelet clumping, that presumably underlies the thrombocytopenia observed in these bleeding disorders.

Humans↗
PubMed1993

Difference in laminin expression between high and low metastatic cell clones derived from murine Lewis lung carcinoma.

We investigated the expression of laminin in two cell lines with different metastatic potentials established from murine Lewis lung carcinoma. Immunostaining of the cells with anti-laminin antibody and Northern blot analysis of laminin mRNA demonstrated that the high metastatic clone expressed less laminin than the low metastatic one. In contrast, expressions of 67 kDa-laminin receptor were at similar levels between these two lines. These findings show the possibility that endogenous laminin may contribute to the difference in metastatic properties in the murine Lewis lung carcinoma cell lines examined.

Animals↗
PubMed1993

Improvement of cardiac performance by pimobendan, a new cardiotonic drug, in the experimental failing dog heart.

The cardiotonic effect of pimobendan was studied in 6 dog heart-lung preparations in which cardiac function had been severely depressed by pentobarbital. Pimobendan in doses of 1-10 mg improved cardiac function in a dose-dependent manner and at 10 mg improved it beyond the control. These doses of pimobendan, however, produced neither a significant increase in heart rate nor arrhythmias. The results indicate that the drug may be of use in the treatment of heart failure.

Animals↗
PubMed1993

Kidney diseases among the elderly--a clinicopathological analysis of 247 elderly patients.

We describe the clinicopathological features of 247 patients over the age of 60 with renal disorders. We acceded the histological classification of WHO recommendation, except for IgA nephropathy as primary glomerulonephritis. All nephrotic patients other than those with diabetic glomerulosclerosis (DGS) or amyloidosis were treated with steroids and/or immunosuppressants. Clinical data showed 88 patients with nephrotic syndrome. The histological study revealed that 142 patients had primary renal diseases and 105 patients had secondary renal diseases. Of 88 nephrotic patients, 35 were membranous nephropathy (MN) and 9 were minimal change nephrotic syndrome (MCNS). In secondary nephrosis, amyloidosis and DGS were diagnosed in 9 and 7 patients, respectively. A good response to therapy was obtained in MN (89%) and MCNS (78%). However, nephrotic patients with mesangial proliferative glomerulonephritis, amyloidosis, or DGS had unfavorable outcomes. Histological observations are useful aids in estimating the prognosis and therapy selection for renal disorders even in elderly patients.

Age Factors↗
PubMed1993

[Pontine control of the internal urethral sphincter activity on decerebrate dogs].

The present study was performed to investigate the pontine control of the internal urethral sphincter (IUS) activity using 13 supracolicular decerebrate female dogs. The lower urinary tract function was evaluated by measuring the bladder and the IUS pressure and the external urethral sphincter (EUS) EMG. Bilateral ureters were cannulated and urine was drained extracorporeally. The bladder neck was ligated to induce a isovolumetric bladder contraction, and the urethra was separated from the bladder to evaluate the function of the bladder and the urethra separately. Electrical stimulation (ES) (0.3 m sec. pulse, 50 Hz, 10-100 microA, 3 sec.) in the pontine micturition center (PMC) was carried out using a microelectrode (10-30 microns in tip diameter). The sympathetic chains, hypogastric nerves and pelvic nerves were identified for preparing the nerve transection. 1) ES in the PMC evoked a bladder contraction and a relaxation of the IUS and EUS. This response was similar to the micturition reflex induced by slow filling of the bladder with saline. 2) The threshold intensity for evoking the IUS pressure drop (i.e. IUS relaxation) was equal to or lower than that for the bladder contraction. The latencies from the ES in the PMC to the IUS relaxation and to the bladder contraction were 0.24 +/- 0.14 sec. (mean +/- S.D.) and 0.42 +/- 0.08 sec., respectively. 3) ES in the PMC evoked the IUS relaxation even when the bladder was empty. 4) Transection of the sympathetic chains had no influence on the IUS relaxation by ES in the PMC. Transection of the hypogastric nerves not only decreased the urethral resting pressure but also reduced the urethral pressure drop by ES. Transection of the pelvic nerves abolished the IUS relaxation as well as the bladder contraction by ES. 5) Phentolamine decreased the urethral pressure between ESs and reduced the degree of the urethral pressure drop to the ES. Phenylephrine increased not only the urethral pressure between ESs but also the degree of the pressure drop by the ES. Propranolol and atropine die not affect the urethral pressure changes to the ESs. Hexamethonium abolished the urethral responses. These results indicate that the PMC regulates the IUS activity as well as the bladder activity. These results also suggest that the excitation of the PMC produces the IUS relaxation through the pelvic nerve pathway as well as the hypogastric nerve pathway. The IUS relaxation through the pelvic nerve pathway is mediated by non-adrenergic and non-cholinergic mechanisms.

Animals↗
PubMed1993

Penetration of cefpirome into sputum in chronic respiratory infections: comparison of administration of 0.5 g and 1.0 g in the same patient.

This study evaluated the sputum penetration of cefpirome following slow intravenous infusion of 0.5 and 1.0 g using a comparative cross-over design to reduce variability. Five patients with chronic respiratory tract infections were randomized to receive either 0.5 g followed by 1.0 g, or by 1.0 g followed by 0.5 g cefpirome, by slow intravenous infusion over 1 h, with a 24-h wash-out period between each treatment. With the exception of one patient, sputum concentration correlated well with plasma concentration. Higher sputum levels of cefpirome were achieved following the higher dose.

Adult↗
PubMed1993

Effect of medication with pravastatin sodium on hemorheological parameters in patients with hyperlipoproteinemia.

Pravastatin sodium, a newly developed potent synthesis inhibitor of HMG-CoA (beta-hydroxy-beta-methylglutaryl-cocarboxylase-A) reductase (Sankyo Co., Ltd., Japan) was medicated, 10 approximately 15 mg/day (mean: 11.1 mg/day) for 10.2 weeks in mean, in 14 patients with primary hyperlipoproteinemia of more than 230 mg/dl of serum cholesterol levels (mean age: 56.9 y.o.). The values of serum cholesterol decreased (from 242 +/- 12 to 207 +/- 22; mg/dl), and of high density lipoprotein (HDL) increased (from 42.3 +/- 8.8 to 45.3 +/- 9.2; mg/dl) significantly (p < 0.05, respectively) 10.2 weeks in mean after medication with pravastatin sodium. The whole blood viscosity, at every shear rate examined, corrected blood viscosity, for the standard hematocrit level of 45%, and plasma fibrinogen decreased significantly (p < 0.05, respectively) at the same time, without showing significant differences any more 10.2 weeks in mean after medication with those in 14 elderly normal subjects (mean age: 56.7 y.o.), which suggested that the hemorheological parameters in patients with primary hyperlipoproteinemia had improved significantly by medication with pravastatin sodium.

Cholesterol↗
PubMed1993

[Gonadotropin receptor system and its signal transduction pathway].

Recent advances in genetic studies have elucidated structure of gonadotropin receptors. This transmembrane receptor contains seven transmembrane domains and induces multiple biological changes in granulosa/theca cells resulting in follicular maturation in women. The signal transduction involves G protein mediated systems, cAMP mediated systems and phospholipase C systems. This paper reviews recent advances in gonadotropin receptor system and its signal transduction pathway.

Amino Acid Sequence↗