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Biomedical subjects

T Ishihara

Publications and source records attributed to T Ishihara.

At least 361 records · Page 20Linked to original sources
PubMed1993

Detection of tracheal stenosis by frequency analysis of tracheal sounds.

To develop a simple noninvasive method for detecting tracheal stenosis, tracheal sounds were analyzed using fast-Fourier transform. The subjects were all female and included 5 normal volunteers and 13 patients with tracheal stenosis mostly secondary to thyroid cancer (11 extrathoracic and 2 intrathoracic lesions). Tracheal sounds were recorded during spontaneous breathing and were digitized with an analog-to-digital converter. Pulmonary functions, including forced expiratory volume in 1 s (FEV1) expressed as percentage of vital capacity, peak expiratory flow rate (PEFR), the ratio of FEV1 to PEFR (Empey's index), and the ratio of expiratory to inspiratory flow rates at 50% vital capacity, were measured. A computed tomography scan was used to obtain the tracheal minimum cross-sectional area. Whereas PEFR demonstrated a weak correlation with the stenotic area, FEV1%, Empey's index, and the ratio of expiratory to inspiratory flow rates at 50% vital capacity did not. The power of the fast-Fourier transform spectrum of normal tracheal sounds decreased as the frequency increased up to 500 Hz. A small spectral peak was observed at approximately 1 kHz. Patients with significant tracheal stenosis demonstrated an increase in the peak spectral power at approximately 1 kHz and in the mean spectral power from 600 to 1,300 Hz in their tracheal sounds. In patients with extrathoracic lesions, the peak and mean spectral powers correlated well with the area of the stenosis as defined by computed tomography scan. In patients with intrathoracic lesions, abnormalities in the pulmonary functions as well as tracheal sound spectra appeared more evident despite milder stenoses.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Growth hormone (GH) secretion from human lymphocytes is up-regulated by GH, but not affected by insulin-like growth factor-I.

Regulation of GH secretion from phytohemagglutinin (PHA)-stimulated lymphocytes was investigated in six normal subjects. Peripheral blood mononuclear cells were incubated with PHA (10 micrograms/mL) in the presence of various amounts of recombinant human GH (0-100 ng/L) and/or recombinant human insulin-like growth factor-I (0-1000 micrograms/L), and the secreted GH was measured by a highly sensitive enzyme immunoassay. PHA-stimulated lymphocytes secreted immunoreactive GH in all subjects (13.6 +/- 2.4 ng/L). Exogenous GH up-regulated the GH secretion in a dose-dependent manner, while IGF-I did not affect either basal GH secretion or the up-regulation by exogenous GH. These findings suggest a difference in the regulation of GH secretion between endocrine and immune systems.

Adult↗
PubMed1993

Effects of exercise and pacing loads on myocardial amino acid balance in patients with normal and stenotic coronary arteries, with special reference to branched chain amino acids.

Arterial and coronary sinus differences (A-S) of alanine, glutamate, isoleucine, leucine, valine and phenylalanine were measured in 7 control subjects and 12 patients with coronary artery disease (CAD) at rest and during exercise, and in 8 controls and 21 CAD patients at rest and during pacing. Lactate, great cardiac vein flow and oxygen were also measured. However, none of these parameters distinguished CAD from controls. Changes in alanine and glutamate during each load were, for the most part, consistent with previous studies, i.e., a greater release of alanine and uptake of glutamate was observed in the ischemic group. A-S of isoleucine, leucine and valine showed significant positive correlation to that of alanine (r = 0.59, r = 0.89, r = 0.77, respectively, during exercise, and r = 0.57, r = 0.65, r = 0.72, respectively, during pacing). A-S of isoleucine, leucine and valine showed significant positive correlations to each arterial concentration during exercise (r = 0.54, r = 0.62, r = 0.63, respectively), but not during pacing. Although none of the uptakes of the branched chain amino acids (BCAA) were significant, the mean A-S of each BCAA was positive at rest in both controls and CAD, and declined during each load. A-S of leucine was significantly smaller in CAD than in controls during exercise (0.7 +/- 7.0 vs 6.8 +/- 4.1 mumol/l, p < 0.05) and those of leucine and valine were significantly smaller in CAD patients with ischemic electrocardiographic change than in those without electrocardiographic change during pacing (0.1 +/- 5.9 vs 6.1 +/- 5.5, p < 0.05; -3.1 +/- 10.1 vs 9.9 +/- 6.8 mumol/l, p < 0.01, respectively). These results suggest that BCAA, especially leucine and valine, tend to be taken up by human myocardium physiologically and show characteristic changes under myocardial stress similar to those seen with alanine and glutamate.

Adult↗
PubMed1993

[Effects of carperitide (alpha-human atrial natriuretic peptide) on acute congestive heart failure in dogs].

Effects of carperitide (alpha-human atrial natriuretic peptide) on hemodynamics and renal function in dogs with congestive heart failure (CHF) produced by volume expansion and ligation of the left anterior descending coronary artery were compared with those of various anti-heart failure agents (cardiotonic, vasodilator and diuretic). Carperitide (0.1-1 microgram/kg/min) dose-dependently decreased the elevated left ventricular end-diastolic pressure (LVEDP). No significant changes in cardiac contractility (LV dP/dtmax) and heart rate (HR) were noted, although cardiac output (CO) tended to reduce during the infusion of carperitide. Nitroglycerin (NG; 3 micrograms/kg/min) and furosemide (1 mg/kg) also decreased LVEDP, but the potency was less than that of carperitide. Sodium nitroprusside (SNP; 10 micrograms/kg/min) and dobutamine (10 micrograms/kg/min) caused a reduction in LVEDP and increased CO with an increase in HR. Hydralazine (H; 100 micrograms/kg/min) increased CO without reduction in LVEDP and induced a pronounced increase in HR. Double product (systolic blood pressure x HR), an index of myocardial oxygen consumption, was significantly reduced by carperitide, but significantly increased by DB and H. Carperitide, unlike NG, SNP, H and DB, increased urine volume and urinary electrolyte excretion. These results suggest that carperitide will be an useful therapeutic agent for the treatment of CHF.

Animals↗
PubMed1993

[Effect of carperitide (alpha-human atrial natriuretic polypeptide) on the cardiovascular system in experimental animals].

The cardiovascular and diuretic actions of carperitide were studied in experimental animals. Carperitide relaxed various canine arteries and veins that were contracted by high K+ or norepinephrine. Carperitide stimulated particulate guanylate cyclase from rat thoracic aortas. Carperitide had almost no effect on coronary perfusion pressure or heart rate, but caused a slight decrease in contractile force in isolated guinea pig hearts. Carperitide tended to decrease isoproterenol-induced renin release from isolated rat kidney slices and elicited decreases in angiotensin II-induced aldosterone release from bovine zona glomerulosa cells. Intravenous injection of carperitide elicited decreases in arterial blood pressure and total peripheral resistance in the anesthetized and conscious dogs. Carperitide also elicited transient increases in cardiac output and coronary blood flow followed by slight decreases in them. Intravenous infusion of carperitide elicited decreases in pulmonary capillary wedge pressure, pulmonary pressure and right atrial pressure in association with elevating plasma carperitide (ANP like immuno-reactivity) level in dogs with heart failure induced by coronary artery occlusion and saline loading. These results suggest that carperitide decreases both preload and afterload and can improve the untoward hemodynamic alterations in animals with acute experimental heart failure.

Animals↗
PubMed1993

A case of late-onset congenital adrenal hyperplasia due to partial 3 beta-hydroxysteroid dehydrogenase deficiency.

Late-onset congenital adrenal hyperplasia due to 3 beta-hydroxysteroid dehydrogenase deficiency has been reported with increasing frequency, but only a few adult women have been found to have this disorder in Japan. We report a 26-year-old Japanese hirsute woman with partial 3 beta-hydroxysteroid dehydrogenase deficiency. The diagnosis was based on significantly increased ratios of 17-hydroxypregnenolone to 17-hydroxyprogesterone and of dehydroepiandrosterone to androstenedione after administration of ACTH. Hirsutism improved with the administration of dexamethasone (0.5 mg) every evening. Since routine assay of delta 5-steroid metabolites has become available, the incidence of this disorder will increase. Diagnostic effort should be attempted since the disorder is treatable with low-dose dexamethasone.

3-Hydroxysteroid Dehydrogenases↗
PubMed1993

Cowden's disease with pulmonary hamartoma.

A case of Cowden's disease is reported. A 38-year-old man was admitted to our hospital because of an abnormal left lung shadow on a chest radiograph. There were no symptoms, although the patient had multiple papules on the nose and pharynx mucosa. There were a few fibromas on the axillas and the inguinal regions. The patient had thyroid goiters, gastrointestinal polyposis, and a pulmonary hamartoma. The latter has not been reported previously in Cowden's disease.

Adult↗
PubMed1993

Superior vena cava syndrome due to Graves' disease.

We encountered a patient with Graves' disease showing superior vena cava (SVC) syndrome. The patient was a 72-year-old woman with diffuse nontoxic goiter (diagnosed as chronic thyroiditis); she developed Graves' disease during L-T4 administration. Radioiodine-131 therapy failed to give sufficient effect, and the intrathoracic goiter became enlarged in association with increases in thyroid stimulating antibody activities, followed by the development of SVC syndrome. The surgically excised thyroid gland was diffuse without any nodules. Microscopic findings revealed adenomatous hyperplasia. The present case, though extremely rare, seems important for the understanding of the mechanism of onset of SVC syndrome in relation to thyroid gland enlargement.

Aged↗
PubMed1993

[Gastric metastasis of primary lung cancer].

A 74-year-old man was admitted to Keio University Hospital because of an abnormal shadow in the right upper lung field on chest roentgenogram. Bronchoscopic examination revealed malignant cells, by which large cell carcinoma of the lung was diagnosed. Systemic survey for metastasis disclosed an ulcerated tumor on the greater curvature of the stomach. Endoscopic examination showed an elevated submucosal tumor suggesting submucosal metastasis of lung cancer to the stomach. A review of 473 autopsies of primary lung cancer at Keio University from 1958 to 1987 showed 16 cases with gastric metastasis (3.4%). Two of 16 cases were detected clinically. Gastric metastases were proven in 15.6% of autopsy cases of large cell carcinoma of the lung. Forty-three cases of primary lung cancer with gastric metastasis were reported in the Japanese literature from 1965 to 1990. Thirteen of these cases had large cell carcinoma.

Aged↗
PubMed1993

[Results of initial bacteriology of pulmonary tuberculosis among male NTT employees in the Tokyo area--annual transition and influence of fiberoptic bronchoscopy].

A study was made on the annual changes in the positive rate for acid-fast bacilli (AFB) at the initial bacteriological examination of newly detected pulmonary tuberculosis among male NTT (Nippon Telegraph and Telephone Corporation) employees in the Tokyo area during a period of 32 years from 1960 through 1991. The influence on the changes of recent introduction of fiberoptic bronchoscopy for obtaining the specimen was also analyzed, and the following results were obtained. 1. Results obtained by the conventional bacteriological method using expectorated sputum or aspirated gastric juice as the specimens. (1) The annual incidence of bacteriologically positive (smear and/or culture positive) cases constantly decreased and reached the lowest in 1981, then ceased to decline and remained at the level of 1981. (2) The annual ratio of AFB positive by smear and the ratio of smear and/or culture positive cases to the newly detected cases of pulmonary tuberculosis were constant during the entire observation period. (3) The ratio of AFB positive by smear to the newly detected cases annually increased but did not increase when the observation period was limited to within 1976 to 1991. 2. Results obtained by fiberoptic bronchoscopy in combination with conventional bacteriological methods. (1) Both the annual incidence of smear and/or culture positive cases and the ratio of these cases to the newly detected cases of pulmonary tuberculosis showed a tendency to increase in both the 80's and 90's.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

[Pharmacokinetic and clinical studies of S-1108 in the pediatric field].

Pharmacokinetic and clinical studies on S-1108, a new oral cephem antibiotic, were performed in the field pediatrics. The following results were obtained. 1) Antibacterial activities Antibacterial activities of S-1006, the active form of S-1108, were studied against clinically isolated strains of (Staphylococcus aureus (n = 5), Streptococcus pneumoniae (n = 6), Streptococcus pyogenes (n = 3), Haemophilus influenzae (n = 8), Branhamella catarrhalis (n = 5) and Haemophilus parainfluenzae (n = 2). MIC values ranged < or = 0.025-1.56 for GPC and < or = 0.025-0.78 microgram/ml for GNR. 2) Absorption and excretion Blood concentrations and urinary excretion rates of S-1108 were measured upon administration of S-1108 after meal at dose of 3 mg/kg (n = 4), 4 mg/kg (n = 1) and 6 mg/kg (n = 1). The peak blood concentrations of S-1006 at a dose of 3 mg/kg (n = 4), ranged from 0.57 to 1.82 micrograms/ml at 1, 2 and 4 hours after dosing. Mean pharmacokinetic parameters T1/2 and AUC were 1.29 +/- 0.69 hours and 4.47 +/- 2.25 micrograms.hr/ml, respectively. At a dose of 4 mg/kg and 6 mg/kg, peak concentrations were 1.79 and 1.27 micrograms/ml at 2 and 3 hours after treatment. T1/2 and AUC were 1.34 and 1.11 hours, and 8.19 and 5.65 micrograms.hr/ml, respectively. Urinary recovery rates ranged from 13.0 to 37.2% for the first 8 hours after administration. 3) Clinical studies Clinical efficacies were examined in 32 cases of various pediatric infections including 5 cases of acute pneumonia, 11 cases of bronchitis, 2 cases of scarlet fever, 8 cases of tonsillitis, 1 case of pharyngitis, 2 cases of otitis media and 3 cases of UTI. Clinical efficacy rate was 96.9% (31/32) and bacteriological eradication rate was 87.1% (27/31). There were no side effects and abnormal laboratory test values except 1 case (Eosino. 2-->10%) in the 32 cases.

Absorption↗
PubMed1993

[Treatment of common bile duct stones by peroral cholangioscopy].

Endoscopic papillotomy (EPT) has become a popular form of treatment in managing common bile duct stones. But it may fail in difficult cases such as large stones of over 20 mm, confluence stones, and impacted stones. Over the past 5 years, our success rate in clearing the bile duct by conventional endoscopic techniques (mechanical lithotripsy) was about 90 per cent. Recently, we have performed electrohydraulic lithotripsy or laser lithotripsy with peroral cholangioscopy in these difficult cases. Complete clearance of the duct was obtained in all 23 patients who underwent peroral cholangioscopic lithotripsy. No complication occurred. In conclusion, peroral endoscopic treatment of common bile duct stones should be safe and effective.

Aged↗
PubMed1993

[Bacteriological, pharmacokinetic and clinical studies of cefditoren pivoxil in the pediatric field].

Bacteriological, pharmacokinetic and clinical studies on cefditoren pivoxil (CDTR-PI, ME 1207) in granules, a new oral cephalosporin, were performed in the field of pediatrics. The results are summarized below. 1. Antibacterial activities: Antibacterial activities of CDTR were studied against Staphylococcus aureus, Streptococcus pneumoniae, Streptococcus pyogenes, Haemophilus influenzae, Haemophilus parainfluenzae and Branhamella catarrhalis in comparison with those of cefteram (CFTM), cefixime (CFIX), cefaclor (CCL), cefpodoxime (CPDX) and cefotiam (CTM). MIC80's of CDTR against S. aureus, S. pneumoniae, S. pyogenes, H. influenzae, H. parainfluenzae and B. catarrhalis were 1.56, 0.39, < or = 0.025, < or = 0.025, 0.05 and 0.20 micrograms/ml, respectively. These results showed that CDTR has high antibacterial activities against these organisms. 2. Absorption and excretion: Serum concentrations and urinary recovery rates of CDTR-PI (administered in granules) were determined. Upon single oral doses of 3 mg/kg and 6 mg/kg, the peak serum concentrations were 0.5-2.45 micrograms/ml at 2 to 4 hours and 1.79-4.05 micrograms/ml at 1 to 4 hours, respectively, and T 1/2 was 1.07-9.67 hours and 0.99-3.00 hours, respectively. At 8 hours after dosing, serum concentrations were 0-0.87 micrograms/ml with a dose of 3 mg/kg and 0.27-0.73 micrograms/ml with 6 mg/kg. These values indicated that the drug has a dose-dependent pharmacokinetic behavior. Urinary recovery rates in the first 8 hours were 12.9-34.2% with a dose of 3 mg/kg and 11.8-26.9% with 6 mg/kg. 3. Clinical study: Clinical efficacies were examined in a total of 81 cases consisting of 20 cases of acute bronchitis, 13 of acute pneumonia, 21 of tonsillitis, 5 of pharyngitis, 7 of scarlet fever, 2 each of impetigo, otitis media and purulent cervical lymphadenitis, 1 of pertussis and 8 of UTI. The clinical efficacy rate was 97.5% (79/81), and bacteriological eradication rate was 100% (76/76). As for side effects, 2 cases of watery stools and 1 case of minor elevation of GPT were observed.

Administration, Oral↗
PubMed1993

[A combination chemotherapy of carboplatin and etoposide for malignant fibrous histiocytoma with marked effect on the metastatic lung region].

For metastatic lung region, a 82-year-old woman with malignant fibrous histiocytoma was successfully treated with combination chemotherapy of Carboplatin and Etoposide. First, the tumor appeared on her right thigh, and we operated on August 1991. However, at the same time, a metastatic lung region was also noticed. Over a year, it worsened. We gave her 350 mg Carboplatin once a week and 100 mg Etoposide 3 times a week. After 3 weeks' treatment, we stopped treatment because of sudden granulocytopenia and thrombocytopenia. But to our surprise, the metastatic lung region almost disappeared 2 months after therapy. Considering the difficulty of medical treatment for malignant fibrous histiocytoma, this case suggests that combination chemotherapy of Carboplatin and Etoposide is valuable. However, due care must be taken for side effects such as granulocytopenia and thrombocytopenia.

Aged↗
PubMed1992

(6R)-5,6,7,8-tetrahydro-L-biopterin modulates nitric oxide-associated soluble guanylate cyclase activity in the rat cerebellum.

(6R)-5,6,7,8-Tetrahydro-L-biopterin (R-THBP) is a cofactor not only for aromatic amino acid hydroxylases in mammalian tissues but also for nitric oxide synthase (NOS) induced by endotoxins or cytokines in some kinds of cells. Recently it has been reported that nitric oxide (NO) has biological activity in endothelium and in brain as well. NO activates soluble guanylate cyclase (sGC). Superoxide reacts with NO easily and shortens the half-life of NO actions. We found, in a study using rat cerebellar cytosol fraction, that R-THBP itself did not directly activate sGC, but activated sGC at concentrations ranging from 0.1 to 10 microM only under NO generating conditions of activated NOS and in the presence of sodium nitroprusside. In addition, R-THBP (1 microM) did not alter the NOS activity, which was determined by L-citrulline formation. These results suggest that R-THBP may regulate sGC activity associated with NO formation in the central nervous system.

Animals↗