PubMed Health⌕ Search

Biomedical subjects

S Hosoda

Publications and source records attributed to S Hosoda.

At least 19 recordsLinked to original sources
PubMed1992

Cloning and characterization of gastrin receptor from ECL carcinoid tumor of Mastomys natalensis.

We report here the cDNA cloning of a putative gastrin receptor from enterochromaffin-like (ECL) carcinoid tumor of Mastomys natalensis. For this study, we used the polymerase chain reaction technique to amplify transmembrane domain sequences related to rat pancreatic cholecystokinin (CCK)-A receptor from the ECL tumor cDNA library. The amino acid sequence deduced from the cloned cDNA showed 85.7% and 49.0% identity to canine parietal cell gastrin receptor and rat pancreatic CCK-A receptor, respectively. Ligand binding studies using COS-7 cells transfected with the cDNA showed the same binding specificity for gastrin and CCK-8 as the gastrin receptor on the Mastomys carcinoid tumor membrane. Both gastrin and CCK-8 elevated free cytosolic calcium concentration in COS-7 cells expressing the cloned receptor. RNA blot analysis revealed the expression of the gastrin receptor in both Mastomys stomach and brain.

Amino Acid Sequence↗
PubMed1992

Echocardiographic findings and clinical features of left ventricular pseudoaneurysm after mitral valve replacement.

We studied the echocardiographic findings and clinical features of left ventricular pseudoaneurysm after mitral valve replacement. From December 1979 to March 1991, 1050 patients underwent mitral valve replacement at our institute, and eight patients (0.8%) had left ventricular pseudoaneurysm. In all eight patients, left ventricular pseudoaneurysm developed after the second mitral valve replacement. The incidence of left ventricular pseudoaneurysm among 253 patients who had had previous mitral valve surgery was 3.1%. Seven of the eight patients were still alive and were followed up from 5 to 136 months (mean, 57 months) after the development of left ventricular pseudoaneurysm; these patients had no complications. One patient died as a result of low cardiac output after mitral valve replacement in spite of repair of the left ventricular pseudoaneurysm. This patient had a long and wide myocardial laceration near the left ventricular pseudoaneurysm. In the other seven patients, transthoracic echocardiography demonstrated a large extraventricular cavity along the posterobasal left ventricle. In five of these patients, a turbulent flow in the neck of the left ventricular pseudoaneurysm was recorded both in systole and diastole by pulsed and color Doppler echocardiography. Transesophageal echocardiography clearly showed the narrow neck of the left ventricular pseudoaneurysm and an abnormal flow between the left ventricle and the left ventricular pseudoaneurysm. Generally, when left ventricular pseudoaneurysm develops after mitral valve replacement, surgical repair is the first choice of therapy. Our study demonstrated, however, that the development of left ventricular pseudoaneurysm was not always associated with a poor prognosis without surgical intervention.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

Accelerated purine nucleotide degradation by anaerobic but not by aerobic ergometer muscle exercise.

The exact conditions under which exercise causes purine nucleotide degradation are not well understood. We determined plasma hypoxanthine and uric acid levels serially in eight individuals during ergometer muscle exercise. When the load was increased gradually by 15 W/min, plasma hypoxanthine was elevated only after the status exceeded the anaerobic threshold (AT), as determined by analysis of expired gas. Nonstrenuous ergometer exercise, which kept the status continuously below the AT, induced neither blood lactic acid nor plasma hypoxanthine elevation. These results suggest that the AT is also the threshold for the acceleration of purine nucleotide degradation. Muscle exercise to a degree that does not exceed the AT does not cause major purine nucleotide degradation, and, therefore, is expected to be beneficial for patients with gout and/or hyperuricemia.

Adult↗
PubMed1992

Trisomy 4 in a case of acute lymphocytic leukemia (L1).

Trisomy 4 has been identified previously as a chromosome abnormality associated with acute nonlymphocytic leukemia (ANLL) with myelomonocytic lineage and in myelodysplastic syndromes (MDS). We report a case of acute lymphocytic leukemia (ALL) (French-American-British, FAB L1) in a 42-year-old Japanese man, with trisomy 4 as the sole chromosomal anomaly. Immunophenotypically, the leukemic blasts demonstrated reactivity with CD2, CD5, and CD7 and indicated on early stage of T cell.

Adult↗
PubMed1992

Carcinoid tumor of the middle ear containing serotonin and multiple peptide hormones. A case report and review of the pathology literature.

A 69-year-old man complaining of longstanding hearing loss and mild otorrhea was found to have a mass obliterating the external auditory canal and polypous tympanic mucosa with accompanying absence of the tympanic membrane and ossicular chain. Tumors excised from the external auditory canal and tympanum showed histologic features essentially characteristic of a carcinoid tumor: a ribbon or festoon arrangement of tumor cells, formation of anastomosing cords and glandular spaces, presence of numerous argyrophilic as well as argentaffin secretory granules within many of the tumor cells, and ultrastructural evidence of neurosecretory granules in the tumor cell cytoplasm. Immunohistochemically, the tumor was found to contain not only neuronal marker substances such as neuron-specific enolase, S-100 protein and chromogranin A, but also serotonin and multiple peptide hormones such as pancreatic polypeptide, glucagon, cholecystokinin and leucine-enkephalin. A review of the pathology of 17 previous cases of carcinoid of the middle ear suggested that this type of carcinoid may have a variegated hormone profile among carcinoids of foregut origin, and hormonally may resemble ileal carcinoid arising from the midgut, although their histogenetic origins may differ, because of frequent production of serotonin.

Aged↗
PubMed1992

Background current in sino-atrial node cells of the rabbit heart.

1. The Ca2+ current, K+ current, hyperpolarization-activated current, Na(+)-K+ pump current and the Na(+)-Ca2+ exchange current were all blocked by appropriate blockers and the remaining time-independent currents were investigated in single pacemaker cells of the rabbit sino-atrial node using the whole-cell patch clamp technique. 2. Exchanging the bathing solution from Tris-hydroxymethyl-aminomethane hydrochloride (Tris) Na+ free to 150 mM-Na+ induced an inward current and the slope conductance of the current-voltage relationship increased from 0.45 +/- 0.18 to 0.87 +/- 0.33 nS (n = 71) at -50 mV. The remaining conductance in Tris Na(+)-free solution was essentially the same when Tris was substituted with tetraethylammonium (TEA) or N-methyl-D-glucamine (NMG). The current density of the Na(+)-dependent inward current obtained by subtracting the current in Tris Na(+)-free from that in 150 mM-Na+ solution was 0.73 +/- 0.21 pA/pF (n = 71) at -50 mV. We called this current the Na(+)-dependent background current. 3. The membrane conductance was reduced by lowering the temperature of the external solution from 36 to 23 degrees C. In Tris Na(+)-free solution, the temperature-sensitive component was outward at all potentials, whereas it showed a reversal potential at around -20 mV in 150 mM-Na+ solution. This reversal potential was interpreted as a sum of the Cs+ efflux and Na+ influx, by comparing the Na(+)-dependent inward currents obtained at 36 degrees C and those at 23 degrees C. 4. Divalent cations (2 mM-Ni2+, 1 mM-Ba2+ or 2 mM-Ca2+) reduced only the outward current in the Tris Na(+)-free solution, while in the 150 mM-Na+ solution, they reduced both the inward and outward components of the current which had a reversal potential of around -10 mV. 5. Amiloride depressed the membrane conductance in 150 mM-Na+, Cs+ or Rb+ external solution, though only at negative membrane potentials, which suggests amiloride has a voltage-dependent effect on the background current. 6. Removal of Cl- from the external solution or the addition of a Cl- channel blocker (4,4'-dinitrostilbene-2,2'-disulphonic acid disodium salt, DNDS) failed to affect the membrane conductance. 7. When the monovalent cation-dependent inward current was measured by subtracting the current in the Tris solution from those recorded in the various monovalent cation solutions, the current amplitude decreased in the order: Rb+ greater than K+ greater than Cs+ greater than Na+ greater than Li+, which suggests a poor cation selectivity of this current system.(ABSTRACT TRUNCATED AT 400 WORDS)

Amiloride↗
PubMed1992

The response to drug therapy in unstable angina on the basis of coronary angiography findings.

Among 366 unstable angina pectoris patients at our hospital, myocardial infarction was common (15.7%) in those with attacks of chest pain lasting for at least 20 min. There was also a high incidence (30.3%) when chest pain continued after the start of inpatient treatment. To investigate the etiology of unstable angina, coronary arteriography was performed in both the unstable and stable stages in these patients and the results were compared. The role of coronary spasm and coronary thrombosis in unstable angina was investigated, and the efficacy of continuous infusion of either diltiazem or isosorbide dinitrate as treatment for these patients was compared. Coronary arteriography in the unstable stage showed, no clear differences in the morphology of the stenotic site and the degree of stenosis between the patients with and without infarcts when urokinase or isosorbide dinitrate were injected into the coronary arteries. When drug treatment was effective, the angina was stabilized without any improvement in the degree of stenosis or the morphology of the involved coronary vessel. Thus, it was difficult to predict the response to treatment from coronary arteriography performed in the unstable stage. Diltiazem was more effective than isosorbide dinitrate, and it appears that some action other than coronary dilatation was involved in achieving the remission of unstable angina.

Angina, Unstable↗
PubMed1992

Evaluation of proarrhythmic effect of antiarrhythmic drugs on ventricular tachycardia associated with congestive heart failure.

The usefulness and limitations of antiarrhythmic drugs in ventricular tachycardias (VT) associated with congestive heart failure remain uncertain. The purpose of this study is to evaluate the proarrhythmic effects of antiarrhythmic drugs in patients with refractory VT associated with left ventricular dysfunction using electrophysiologic study (EPS). Twenty-four patients with left ventricular dysfunction, defined by left ventricular ejection fraction (LVEF) lower than 40% using left ventriculography, were studied. The average LVEF was 29.5%. As for underlying heart disease, 14 had old myocardial infarction, 8 cases had dilated cardiomyopathy and 2 had aortic regurgitation. As a control to this group, 23 cases with underlying heart disease and LVEF higher than 40%, and 27 cases with no obvious heart disease were studied. We considered a drug to have proarrhythmic effects if 1) it decreased by one the number of stimuli needed to induce VT, 2) induced non-sustained VT in the control study which changed to induced sustained VT, 3) the sustained VT or ventricular fibrillation was newly induced, or 4) the induced sustained VT which was stopped by pacing in the control study changed to induced VT which could not be terminated by pacing and required DC shock. Proarrhythmic effects were recognized in 17 of 24 cases with left ventricular dysfunction. Of the 67 drug trials, proarrythmic effects were seen in 26. Proarrhythmias were observed in 9 of 23 cases (39.1%) with organic heart disease associated with LVEF higher than 40%. In 12 of 69 drug trials (17.4%) proarrhythmias were observed. Of 27 cases with no obvious heart disease 10 cases (37%) had proarrhythmias. In 14 of 130 drug trials (10.8%), proarrhythmias were recognized.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Effect of pectin on formyl methionyl-leucyl-phenylalanine (FMLP)-injured intestinal mucosa of rat.

(1) We investigated the trophic effect of pectin on the intestinal mucosa injured by formyl methionyl-leucyl-phenylalanine (FMLP), a chemoattractant produced by the intestinal bacterial flora. (2) We first demonstrated that oral administration of FMLP for 7 days reduced the disaccharidase activities and increased the permeability, measured by fluorescein-isothiocyanate-conjugated dextran, of rat small intestine. (3) After 7 days of FMLP administration, rats were divided into fiber-free group which was given liquid elemental diet (Elental) and the pectin group which was given Elental supplemented with 2.5% pectin. (4) After 3 days of feeding (Day 3), the maltase activities of the pectin group was significantly greater than that of the fiber-free group and than that of the initial level just after the 1 week administration of FMLP. At Day 7, there was no difference of maltase activity between the two groups. The sucrase activity of the pectin group was also significantly greater than that of fiber-free group at Day 3. (5) Plasma enteroglucagon was significantly increased in the pectin group. We conclude that pectin-supplemented diet promoted the recovery of disaccharidase activities in the FMLP-injured intestinal mucosa which may be mediated by enteroglucagon.

Animals↗
PubMed1992

[Aplastic anemia successfully treated with erythropoietin and rhG-CSF].

A 32 year-old female admitted to our hospital with pancytopenia. The hematological data on admission were: RBC: 247 x 10(4)/microliters, Hb: 8.8 g/dl, Plts: 13,000/microliters, WBC: 2,500/microliters. Bone marrow aspirate and biopsied specimen showed marked hypocellularity without infiltration of abnormal cells. A diagnosis of aplastic anemia was made. Neither high-dose methyl-prednisolone pulse therapy nor anti-lymphocyte globulin were effective. With combination of oxymetholone (30 mg/day), recombinant erythropoietin (rHuEpo; 12,000 U/day, three times a week) and recombinant granulocyte-colony simulating factor (rHuG-CSF; 33 micrograms/day) for 3 months, remarkable improvements of hematological data were obtained. Her hemoglobin level reached 11.4 g/dl, and platelets count 49,000/microliters. However, 4 weeks after the withdrawal of erythropoietin and G-CSF administrations, her platelet count fell to 12,000/microliters. It was suggested that combination therapy with erythropoietin and G-CSF were effective for aplastic anemia.

Adult↗
PubMed1992

[Experimental study of the mechanism of auranofin-induced diarrhea].

To clarify the kinetics of cell membrane and intracellular mediators in the process of auranofin (AF)-induced diarrhea, we perfused electrolyte solution containing the oral gold preparation AF, which is a treatment for rheumatoid arthritis, through the rat jejunum, and studied net water and electrolyte transport, Na+, K(+)-ATPase activity, and c-AMP and c-GMP concentrations in the jejunal mucosa. In addition, change in Ca+ concentration in isolated intestinal cells was evaluated using fura-2-acetoxyl-methyl ester. AF significantly suppressed water and electrolyte transport. Mucosal secretion was increased due to elevation of the intracellular Ca+ concentration early in the perfusion period, then due to reduction in the Na+, K(+)-ATPase activity, and increase in the c-AMP concentration late in the perfusion period. Therefore, these cell membranes and intracellular mediators are considered to be involved in the mechanism of AF-induced diarrhea.

Animals↗