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Biomedical subjects

T Sakamoto

Publications and source records attributed to T Sakamoto.

At least 559 records · Page 31Linked to original sources
PubMed1996

[Electron microscopic histochemical studies on the localization of hyaluronic acid in Wharton's jelly of the human umbilical cord].

The mode and distribution of hyaluronic acid in Wharton's jelly of the human umbilical cord was studied by the electron microscopic histochemical technique. By means of ruthenium red (RR) staining, RR-positive material was observed as granules approximately 30nm in diameter in the fibroblast of Wharton's jelly. Around the fibroblast, it was observed as fibril structures on the cell surface or as granules approximately 13nm in diameter in the basement membrane-like structure around the cell. In the extracellular matrix, it was observed as granules or amorphous materials on collagen fibrils. Only the 30nm granules in RR positive structures disappeared due to amylase digestion. The other structures were digested by Streptomyces hyaluronidase. On the basis of the above findings, it was concluded that hyaluronic acid is formed as hydrated gel around the fibroblast and collagen fibrils in Wharton's jelly of the human umbilical cord. These results suggest that its structure is one of the factors in maintaining the elastic aptitude of the umbilical cord, to protect from any pressure, such as fetal movement, etc., in the uterine cavity.

Extracellular Matrix↗
PubMed1996

[Clinical effects of urokinase and sodium ozagrel in patients with acute symptomatic lacunar infarction].

The clinical effects were compared between a thrombolytic agent (urokinase) and a thromboxane synthetase inhibitor (sodium ozagrel) in patients with acute lacunar infarction. All patients had some degree of neurological deficits, which corresponded to the lesions on computerized tomography or magnetic resonance imaging. Urokinase of 420,000 units was given over two days in 11 patients, 160 mg/day of sodium ozagrel was administered for two weeks in 23 patients. The study was followed up to one month after the onset. Urokinase treatment improved motor paresis in 45.5-62.5% of the patients, sodium ozagrel in 68.4-86.7%. Using the combined score of motor paresis and conscious disorder, urokinase group revealed 44.4-45.5% improvement, but sodium ozagrel group 81.0-89.5% (p < 0.05). The rates of suppressive effect in progressing stroke and complete recovery were higher in sodium ozagrel group. Sodium ozagrel was clinically more efficient than urokinase in patients with lacunar infarction.

Acute Disease↗
PubMed1996

[Inhibitory effect of vitamin E succinate on the proliferation of cultured bovine choroidal endothelial cells].

We report the effect of vitamin E succinate (VE succinate) on the proliferation of cultured bovine choroidal endothelial cells (BCECs). BCECs were incubated with a medium containing vitamin E (VE) or one of the VE derivatives gamma-tocopherol, VE phosphate, VE succinate, VE nicotinate, VE acetate, or trolox, at a concentration of 10 microM. The proliferation of BCECs was assessed by 3H-thymidine uptake and cell counting. Especially in VE and VE succinate, the proliferation assay was performed on BCECs at two different stages, that is, the proliferating stage and the quiescent stage. The effect of protein kinase C (PKC) stimulator phorbol ester (PMA) on the VE succinate-induced inhibition of BCEC proliferation was also examined. VE succinate was found to significantly inhibit BCEC proliferation at a concentration of 10 microM or greater both by 3H-thymidine uptake assay and by cell counting. This inhibitory effect was not noted in other VE derivatives. The inhibitory effect was the most prominent in the proliferating BCECs and co culture of PMA. VE succinate inhibits the proliferation of cultured BCECs and PKC is involved in this action at least in part.

Animals↗
PubMed1996

[Mitral reconstruction in patients with infective endocarditis].

Between June 1992 and October 1993, 5 patients with infective endocarditis in native mitral valve underwent open heart surgery. The patients ranged in age from 51 to 64 years and were all males. According to NYHA functional classification, 4 patients were class II and one was class III. Surgery was indicated because of hemodynamic deterioration (2 pts), echocardiographic mobile vegetation with or without previous emboli (2 pts) and both condition (1 pt). Before surgery the patients were afebrile and had negative serum CRP and negative blood cultures for at least one week after adequate medical treatment. The leaflet lesions found in the 5 patients were vegetation (2 pts), perforation (1 pt), calcification (1 pt) and thickening (2 pts). The chordal lesions found were rupture (5 pts) and thickening (1 pt). The infective lesions did not extend to the annulus. The mitral leaflets, including all apparently infectious lesions, were resected in a V-shaped fashion and then valve reconstruction was performed. The resected parts were sutured together with anchoring chordae. The annuloplasty with Teflon-tapes was also added. Postoperatively, all 5 patients showed a dramatic improvement in hemodynamics and endocarditis did not recur during 22 to 38 months of follow-up. The patients who received the repair did not require Warfarin. This study shows that mitral valve repair is an acceptable operation in patients with infective endocarditis, giving the patients better quality of life than mitral valve replacement when (1) infectious lesion are limited to mitral leaflet and chordae, (2) there is no severe calcification of the mitral valve, (3) the infection is healed by the adequate antibiotic therapy.

Endocarditis, Bacterial↗
PubMed1996

[Anesthetic management for a patient with pheochromocytoma using magnesium sulfate and epidural block].

A 54-year-old woman with pheochromocytoma was anesthetized using magnesium sulfate infusion. Anesthesia was induced with thiopental and fentanyl, and maintained with 0.5% sevoflurane in nitrous oxide/oxygen and 60 mg.hr-1 of epidurally infused lidocaine. Muscle relaxation was achieved with intermittent administration of vecuronium under neuromuscular monitoring. Magnesium 2 g was infused prior to the tracheal intubation and followed by continuous infusion of 2 g.hr-1. These anesthetic techniques made hemodynamic state stable, and no additional vasoactive agents were needed. However, the infusion rate of magnesium was reduced to a half because of PQ interval prolongation. Magnesium is believed to be useful for anesthetic management for patients with pheochromocytoma, but the proper dose and the way of administration should be further investigated for their safe clinical use.

Adrenal Gland Neoplasms↗
PubMed1996

Two survival cases of alcoholic lactic acidosis complicated with diabetes mellitus and alcoholic liver disease.

We have experienced two patients with alcoholic lactic acidosis complicated with liver disease and diabetes mellitus who were successfully treated. They developed hypoglycemia, dehydration, lactic acidosis, and renal failure after drinking a large volume of alcohol without eating for 1 week before onset. Acidosis was thought to be directly related to excessive alcoholic intake, because it was no associated with severe liver failure and rhabdomyolysis. During monitoring of respiratory and circulatory functions, a rapid infusion of fluids adjusting to water and electrolyte imbalance was performed. A mixture of physiological saline and 5% glucose solution was thought to be effective in these cases. Patients recovered from renal failure and lactic acidosis without hemodialysis. Our experience will hopefully provide a key to successful treatment of fatal alcoholic lactic acidosis.

Acidosis, Lactic↗
PubMed1996

Progressive zonal outer retinitis.

A 27-year-old woman with uniocular progressive zonal outer retinitis was examined. The retinitis area was curvilinear and gray, with zonal opacification. It enlarged centrifugally and concentrically, with narrowing of the zonal opacification. Results of perimetry and electroretinography showed that the outer retina was primarily affected. Damage was more severe in the photoreceptor cones than in the rods. Peripheral retinal phlebitis was seen on fluorescein angiography. Intraretinal pigment migration with retinal pigment epithelial atrophy occurred in the macula as sequelae.

Adult↗
PubMed1996

Effect of hyperthermia on proliferation and deviation of carcinoembryonic antigen and squamous cell carcinoma-related antigen of human esophageal carcinoma cells in culture.

As a basic study of hyperthermia on malignant tumors, we investigated the kinetics of proliferative activity and the values of tumor markers carcinoembryonic antigen (CEA) and squamous cell carcinoma-related antigen (SCC) in a human esophageal carcinoma cell line, SGF-4, following a change of culture temperature. The temperature range allowing cultured SGF-4 cells to proliferate was from 37 degrees C to 40 degrees C. In an experiment examining the recovery of proliferative activity, no proliferative activity was observed after the cultured cells were exposed to 42 degrees C for 72 hours. The values of CEA and SCC as tumor markers were found to be increased in association with the cell damage due to the change of temperature. These markers could thus be useful as indicators for evaluations of hyperthermia therapy effectiveness.

Aged↗
PubMed1995

Monoclonal antibody against the polymorphic site distinguishes apolipoprotein E4 from other isoforms.

Apolipoprotein E4 has been confirmed as a genetic risk factor for Alzheimer's disease. Although several hypotheses have been advanced to explain how the inheritance of apolipoprotein E isoforms affects the rate of Alzheimer's disease expression, the mechanism whereby apolipoprotein E is involved in the pathogenesis of Alzheimer's disease is still uncertain. To clarify the way in which the apolipoprotein E4 isoform differs from the others, we generated a monoclonal antibody specifically reactive with the apolipoprotein E4 isoform. This antibody suggests that the polymorphic site is important in differentiating the ApoE4 isoform from others.

Alzheimer Disease↗
PubMed1995

Down-regulation of bcl-xs gene expression in rat thymocytes by dexamethasone.

In order to test a hypothesis that the expression of bcl-x gene promotes apoptosis by antagonizing the function of bcl-2 gene product, time course of the expression of bcl-x was investigated using the dexamethasone-treated rat thymocytes which were undergoing apoptosis. Unexpectedly, dexamethasone suppressed the expression of bcl-x in a dose- and time-dependent manner. Such decrease was detected even in the presence of cycloheximide, suggesting that the suppression is due to the genomic (primary) effect of dexamethasone. Since the expression of bcl-xL, as measured by a specific nucleotide probe, was not detected at a quantifiable level, the decrease was apparently attributed to that in bcl-xS. Our present observations propose a new role of the bcl-xS gene product, in which the bcl-x gene product may be necessary for survival of immature thymocytes rather than for their apoptosis.

Animals↗
PubMed1995

Soluble P-selectin is released into the coronary circulation after coronary spasm.

BACKGROUND: The glycoprotein P-selectin is an adhesion molecule involved in the property change of leukocytes at the initiation of the inflammatory process. The purpose of the present study was to determine whether acute myocardial ischemia induced by coronary spasm causes an acute inflammatory response in the coronary circulation. METHODS AND RESULTS: We examined plasma soluble P-selectin levels in the coronary sinus and the aortic root simultaneously in 16 patients with coronary spastic angina before and after left coronary artery spasm induced by intracoronary injection of acetylcholine and in 15 patients with stable exertional angina before and after acute myocardial ischemia induced by rapid atrial pacing. Ten control patients with chest pain but normal coronary arteries and no coronary spasm also received intracoronary acetylcholine. Plasma soluble P-selectin levels were increased significantly in the coronary sinus (32.8 +/- 3.6 to 52.8 +/- 5.9 ng/mL, P < .001) and in the aortic root (34.6 +/- 3.7 to 41.9 +/- 4.4 ng/mL, P < .05) after the attacks in the coronary spastic angina group but remained unchanged in the stable exertional angina group after the attacks and in the control group after the administration of acetylcholine. Furthermore, the coronary sinus-arterial difference of soluble P-selectin increased significantly after the attacks in the coronary spastic angina group (-1.8 +/- 2.2 to 10.9 +/- 2.7 ng/mL, P < .001). CONCLUSIONS: Our data indicate that soluble P-selectin is released into the coronary circulation after coronary artery spasm. We conclude that coronary artery spasm may induce the leukocyte adhesion in the coronary circulation and may lead to myocardial damage.

Acetylcholine↗
PubMed1995

Increased muscle sympathetic nerve activity after glucagon administration in man.

Muscle sympathetic nerve activity (MSNA) after glucagon administration was quantitatively measured in five healthy male volunteers (age: 20-28 years old). After an overnight fasting, 1 mg glucagon dissolved in a 1-ml vehicle was injected i.v. as a bolus. MSNA, ECG and blood pressure were simultaneously recorded 15 min before and after the injection. MSNA (bursts/min), heart rate (HR), and systolic and diastolic blood pressures (dBP and sBP) were significantly increased at 2-3 min after glucagon injection. Their means and standard deviations of control for 15 min vs. 3 min after the injection were in the five subjects; MSNA, 10 +/- 6 vs. 30 +/- 10 bursts/min, HR, 61 +/- 10 vs. 76 +/- 8 beats/min, dBP, 66 +/- 9 vs. 91 +/- 9 mmHg and sBP, 122 +/- 12 vs. 152 +/- 11 mmHg. These results suggest that glucagon has a direct facilitatory effect on the central sympathetic nervous system.

Adult↗
PubMed1995

The induction of cell differentiation and polarity of tracheal epithelium cultured on the amniotic membrane.

We have developed a culture system of guinea pig tracheal epithelial cells using the epithelium-denuded human amnion as a source of basement membrane. Culture medium fluid over the epithelial cells was replaced by air after 7-day immersion culture and thereafter maintained for 2 weeks. Electron microscopical observations revealed that the height of epithelial cells and the ratio of ciliated epithelial cells looked like that of normal guinea pigs epithelium growth in 2 weeks after the air interface, but that no goblet cells could be found. In order to study cell polarity, we measured endothelin-1 levels in the media of apical and basal sides of the epithelial cell monolayer by means of the enzyme-linked immunosorbent assay. The endothelin-1 content of the submucosal side was over 30 times higher than that of the apical side. These findings suggest that ET-1 would be mainly released from airway epithelial cells toward the submucosal side.

Amnion↗
PubMed1995

An effect of somatostatin on neurotensin secretion.

A somatostatin analog (SMS201-995) was administered subcutaneously to six totally pancreatectomized (TP) patients at five dose levels from 0 microgram/kg (control) to 2.5 micrograms/kg before ingestion of a liquid test meal, and plasma levels of neurotensin (NT) were measured. There were no significant differences in basal levels of NT between the doses of somatostatin. The NT levels were significantly elevated after ingestion of the test meal in the normal controls (n = 14). In the TP patients postprandial hypersecretion of NT was observed. The hypersecretion of NT in the patients was suppressed by SMS201-995 dose-dependently.

Adult↗
PubMed1995

Characterization of high-density apolipoprotein particles A-I and A-I:A-II isolated from humans with cholesteryl ester transfer protein deficiency.

The cholesteryl ester transfer protein (CETP) plays an important role in metabolism of high-density lipoprotein and reverse cholesterol transport in humans. The two major classes of high-density lipoprotein particles are those containing apolipoprotein A-I (LpA-I) and those containing both apoA-I and apoA-II (LpA-I:A-II). We isolated and characterized the apoA-I-containing lipoprotein particles from three subjects with homozygous CETP deficiency (CETP-D) and compared the results with those from normolipidemic control subjects. Plasma concentrations of apoA-I in both LpA-I and LpA-I:A-II were significantly elevated in CETP-D subjects. Both LpA-I and LpA-I:A-II from these subjects were larger and contained more cholesteryl ester per particle than control particles. In CETP-D, subpopulations of LpA-I and LpA-I:A-II with an unusually large size (Stokes diameters 13.8 nm and 12.6 nm, respectively) not detected in normal subjects were isolated. The molar ratio of apoA-I to apoA-II in LpA-I:A-II isolated from CETP-D subjects was higher (mean 2.4) than those of controls (mean 1.4). ApoE was primarily associated with LpA-I:A-II in CETP-D subjects. A subclass of LpA-I with pre-beta migration on agarose electrophoresis was increased in CETP-D subjects. Both LpA-I and LpA-I:A-II from CETP-D subjects bound with higher affinity but less capacity to HepG2 cells compared with control particles, and were internalized to a lesser extent than control particles. These data suggest that the absence of CETP in humans significantly affects the plasma concentration, size, composition, and cellular interaction of both major classes of apoA-I-containing lipoprotein particles.

Adult↗