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Biomedical subjects

M Okamoto

Publications and source records attributed to M Okamoto.

At least 757 records · Page 42Linked to original sources
PubMed1990

[A study of voice mutation and physical growth--a longitudinal observation].

Past studies on the relationship between mutational voice change and body growth were generally made on grouped subjects and no exact longitudinal observation was performed. In the present report, a longitudinal study was made on 100 young male students in their puberty, in which voice recordings and measurements of physical parameters including body height and weight were performed twice for each subject with yearly interval. Information on subjective evaluation of voice abnormality was also obtained from each subject. The recorded voice samples were subjected to subsequent analysis for obtaining fundamental frequency (F0) and formant values. The following results were obtained. 1. A negative correlation in the rate of change was observed between F0 and physical parameters such as body height and weight, and sitting height. 2. It was suggested that the mutational period consisted of the rapid and slow phases. The rate of growth in body height and sitting height was more significant in the rapid phase. 3. Subjective voice abnormality and physical growths such as the development of the laryngeal prominence were often noted even before the rapid phase. After the rapid phase was over, all the cases showed secondary sexual characteristics including the laryngeal prominence. 4. Before and during the rapid phase, there was a tendency for the values of F1 and F2 to increase, while that of F3 to decrease. After the rapid phases was over, there was a trend that F1 and F2 increased, while F3 remained unchanged.

Adolescent↗
PubMed1990

[Effects of speaking tube in patients with dysacousis].

Comparative study was made between the conventional speaking tube and the modern electric hearing aid. The results revealed that the conventional speaking tube was inferior to the electric hearing aid in terms of specificity to various frequencies, advantages and understanding of singular syllables, but almost equal to the latter in terms of understandings of three syllables. Actual comparison by listening with both revealed a face that the speaking tube was more acceptable than the hearing aid in terms of naturalness of voice heard with it. It was assumed that the advantages of the speaking tube like this may be attributable to the less sense closure of eyes as it had an open end and consequently to the better hearing through the speaking tube, which may have made better understandable conversation.

Evaluation Studies as Topic↗
PubMed1990

[A study on tolerance to denopamine, oral beta 1-agonist].

To investigate whether effects of denopamine become weaker or not. Initial single dose (10 mg) effects, single dose effects after long-term treatment (30 mg per day, about 40 days), and chronic effects were studied by Doppler and echocardiography in 23 patients with heart failure (NYHA II-III). 1) Chronic effects: Blood pressure and heart rates didn't change significantly whether they were measured before or after long-term treatment. But left ventricular end-diastolic dimension decreased from 54.6 +/- 10.2 to 53.3 +/- 10.1 mm (p less than 0.01). Percent fractional shortening (%FS) increased from 22.6 +/- 7.8 to 25.3 +/- 8.6% (p less than 0.05). Mean velocity of circumferential fiber shortening (mVCF) tended to increase, and cardiac index (CI) increased from 2.71 +/- 0.47 to 2.98 +/- 0.57 l/min/m2 (p less than 0.01). 2) Initial single dose effects: Blood pressure and heart rates increased significantly. %FS increased from 25.0 +/- 7.7 to 25.9 +/- 7.8% (p less than 0.05), mVCF increased from 0.94 +/- 0.26 to 1.03 +/- 0.28 cir/sec (p less than 0.01), and CI increased from 2.81 +/- 0.49 to 3.09 +/- 0.49 l/min/m2 (p less than 0.01). 3) Single dose effects after long-term treatment: Blood pressure and heart rates increased significantly. %FS tended to increase, mVCF increased from 1.02 +/- 0.27 to 1.09 +/- 0.30 cir/sec (p less than 0.05), and CI increased from 3.05 +/- 0.62 to 3.37 +/- 0.54 l/min/m2 (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1990

Development of a biochemical switching device: mathematical model.

There are many examples of enzymes that share substrates or cofactors in a cyclic manner. Techniques have been developed that use cyclic enzyme systems to assay quantitatively small amounts of biochemical substances (cofactor, substrate), however, only a few studies of the control of these systems have been published. The author previously showed with computer simulations that cyclic enzyme systems have the reliability of ON-OFF types of operation (McCulloch-Pitts' neuronic equation) and the applicability for a switching circuit in a biocomputer. The switching time was inevitably determined in accordance with the difference in amount between two inputs of the system. A unique switching mechanism of cyclic enzyme systems (basic switching element) and the effects of excitatory stimuli on switching properties of the integrated biochemical switching system are demonstrated.

Computer Simulation↗
PubMed1990

[Left atrial systolic time intervals: their relations to left atrial preload, afterload and acute left ventricular pressure loading].

Using pulsed Doppler echocardiography, the left atrial pre-ejection period (LAPEP) and left atrial ejection time (LAET) were studied in relation to left atrial loading and acute left ventricular pressure loading conditions in 17 patients with various heart diseases. LAPEP was defined as the time interval from the onset of a right atrial pacing pulse to the upstroke in the atrial contraction phase on the mitral flow velocity pattern; LAET was defined as the duration of left ventricular filling due to atrial contraction. 1. LAPEP did not correlate significantly with mean pulmonary capillary wedge pressure (mPCWP) indicating preload for the left atrium, nor with left ventricular end-diastolic pressure (LVEDP) indicating afterload for the left atrium. There were significant inverse correlations of LAET with mPCWP (r = -0.72) and with LVEDP (r = -0.75). 2. LAPEP, LAET and LAPEP/LAET correlated significantly with the ratio of the peak velocity in the atrial contraction phase and to that in the rapid filling phase (r = -0.62, -0.50 and -0.59, respectively). There was a significant inverse correlation of LAPEP/LAET with the left ventricular ejection fraction (r = -0.62). 3. When left ventricular systolic pressure became elevated by 25% of its basal value at a constant right atrial pacing rate, LAPEP decreased from 110 +/- 21 msec to 103 +/- 22 msec (p less than 0.05), LAET increased from 123 +/- 33 msec to 129 +/- 24 msec and LAPEP/LAET decreased from 0.95 +/- 0.37 to 0.84 +/- 0.32 (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

[Effects of verapamil and disopyramide phosphate on the termination, reinduction and long-term prevention of paroxysmal supraventricular tachycardia].

The efficacy of verapamil and disopyramide phosphate for the termination and prevention of paroxysmal supraventricular tachycardia (PSVT) were studied electrophysiologically in 32 patients with inducible sustained PSVT (17 patients received verapamil, 15 patients received disopyramide). Twelve patients had atrioventricular nodal tachycardia, 7 had concealed and 13 had overt Wolff-Parkinson-White syndrome. Intravenous verapamil (0.15 mg/kg) terminated the sustained PSVT in 15 of the 17 patients (88%) by production of AV block in 13 patients, VA block in one, and a ventricular premature beat in one. PSVT could not be induced in any of these 15 patients after they had received verapamil. In the remaining 2 patients, PSVT could not be terminated by the use of verapamil, but the cycle lengths of PSVT were lengthened. Long-term oral dosages of verapamil of 120-240 mg/day were administered in 13 of the 17 patients. All patients except two, whose PSVT was unable to be effected by intravenous verapamil, were well controlled: PSVT disappeared in 7 patients and decreased in 4. Intravenous disopyramide (1.5 mg/kg) terminated induced PSVT in 10 of the 15 patients (67%) by production of VA block. Although PSVT could not be reinitiated in 5 of these 10 patients, non-sustained PSVT was induced in 2 and sustained PSVT was induced in 3 after having received disopyramide. PSVT was induced in all of the 5 patients who failed to respond to disopyramide. The cycle lengths of PSVT after administration of disopyramide remained unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1990

[Hemodynamic responses to sublingual nifedipine during exercise and recovery in congestive heart failure].

To elucidate the hemodynamic responses to sublingual nifedipine administration during exercise and recovery in congestive heart failure, 16 patients with dilated cardiomyopathy (DCM) and 11 controls were studied using supine bicycle exercise testing. The cardiac index (CI) was measured at rest, at peak exercise and successively during recovery by the thermodilution method. The heart rate (HR), mean blood pressure (mBP) and mean pulmonary arterial pressure (mPAP) were measured every minute. The same exercise load and hemodynamic measurements were repeated about 30 min after the sublingual administration of 10 mg nifedipine. The recovery slope in each parameter was analyzed using an exponential function (Cp = C1ekt). The regression coefficient in each parameter was defined as a CI slope, an HR slope, an mBP slope and an mPAP slope. Before the administration of nifedipine, CI at peak exercise was lower, mPAP during recovery was persistently higher and the CI slope was more blunt in DCM patients, compared with those of the controls. With the administration of nifedipine, CI and HR increased or tended to increase, mBP decreased throughout the exercise and recovery, and mPAP decreased at rest, at peak exercise and one min after exercise in the controls. In DCM patients, however, the CI increased, mBP and mPAP decreased nearly throughout the exercise and recovery, while HR increased throughout the exercise and recovery, except at peak exercise. The CI, HR and mPAP slopes were blunted in the controls; whereas, each slope showed no change in DCM patients. These results suggest that sublingual nifedipine administration can reduce both the preload and afterload, and increase CI throughout exercise and recovery without significant alteration in the recovery course.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Sublingual↗
PubMed1990

[Clinical electrophysiological effects of nicorandil on the conduction system in humans].

The electrophysiological effects of nicorandil on the conduction system in humans were examined. Twelve patients with sick sinus syndrome (SSS), 3 patients with AV block and 3 subjects with normal conduction system were studied. The clinical electrophysiological effects were examined before, and 5 min after intravenous administration of nicorandil 2 mg over 3 min. Nicorandil increased heart rate in 6 patients and decreased it in 4. Wenckebach point was increased in 5 patients and decreased in 4. Maximum sinus node recovery time was prolonged in 4 of 12 patients with SSS, and shortened in 3 of them. It was unchanged in 6 patients without SSS. These changes were not statistically significant. There were no changes in PA, AH and HV intervals and refractory periods the atrium, the AV node and ventricle. Nicorandil had no depressant effects on the conduction system of humans. Thus, this drug can be used easily for the treatment of ischemic heart disease in patients with some conduction disturbances.

Coronary Disease↗
PubMed1990

[T cell blastogenesis in stored blood can induce GVHD in open heart surgery].

We studied T cell blastogenesis in stored blood during the preservation time within 7 days. Blood samples were obtained from 8 adults and stored at 4 degrees C immediately after donation with CPD (citrate-phosphate-dextrose) for 3,5 and 7 days. After each intervals, mitogenic responses of T cells from the samples in the presence of an optimal dose of PHA as a mitogen and MLR (mixed lymphocyte reaction) with lymphocytes prepared by 2000 rad radiation from other 10 donors as stimulating cells were investigated. The stimulation index (S.I.) of PHA as a responsibility of the stored blood was decreasing to 86.7 +/- 24.8%, 44.2 +/- 12.5% and 31.2 +/- 11.1% in proportion of that of fresh blood after 3, 5 and 7 days preservation. The S.I. of MLR were in the same way decreasing to 92.5 +/- 21.8%, 45.9 +/- 9.8% and 33.3 +/- 10.1% after that. These observations suggest that lymphocytes in stored blood within 7 days are able to induce GVHD (graft-versus-host disease) in open heart surgery of which immunological activity is thought to be decreased by extra-corporeal circulation. We concluded that the stored blood within 7 days should be irradiated to 1500 rad or more in order to prevent GVHD.

Adult↗
PubMed1990

Induction of bone formation in an adenoid cystic carcinoma of the maxillary sinus by adoptive immunotherapy involving intra-arterial injection of lymphokine-activated killer cells and recombinant interleukin-2 in combination with radiotherapy.

A patient with an adenoid cystic carcinoma of the maxillary sinus was treated by adoptive immunotherapy involving intra-arterial injection of lymphokine-activated killer cells (a total number of 7 x 10(7) cells) and recombinant interleukin-2 (a total dose of 2.75 x 10(7) units) in combination with radiotherapy (60Co; total irradiation dose of 5,000 rads). Consequently, it was found that bone formation was induced in the treated tumor, which was then replaced completely by lamellar bone tissue with myxomatous stroma. This finding indicates that the tumor cells composing certain adenoid cystic carcinoma can be converted into normal-appearing, bone-forming cells by current therapy and this differentiation phenomenon leads to cure of the tumor.

Biopsy↗
PubMed1990

[A hepatocellular carcinoma (HCC) with intrahepatic bile duct dilatation and right lobe atrophy following percutaneous ethanol injection therapy].

Reported is the case of a 67-year-old man with an HCC who was being treated by percutaneous ethanol injection therapy (PEIT). After a year, CT and ultrasonography demonstrated the dilatation of the intrahepatic bile duct and the atrophy of the right lobe. Endoscopic cholangiography also showed stenosis of the right hepatic duct. This severe complication and injury to the hepatic duct and portal vein was determined as having occurred because of treatment by PEIT.

Aged↗
PubMed1990

Binding activity and autophosphorylation of the insulin receptor from patients with myotonic dystrophy.

To clarify a mechanism of insulin resistance associated with myotonic dystrophy, we studied the insulin receptor by using three different types of cells--circulating erythrocytes, cultured skin fibroblasts, and Epstein-Barr virus(EBV)-transformed lymphocytes. In myotonic dystrophy, insulin binding to erythrocytes and fibroblasts was significantly decreased as a result of a reduction of the binding affinity. Insulin binding to EBV-transformed lymphocytes was normal. When the receptors were purified from fibroblasts with wheat germ agglutinin, we could not find a decrease in the binding affinity seen in the intact cells. No difference was observed in the magnitude of basal and insulin-stimulated autophosphorylation of insulin receptors from EBV-transformed lymphocytes between the control and myotonic dystrophy. Southern blot analysis of the insulin receptor gene revealed no restriction fragment length polymorphism associated with myotonic dystrophy. These findings suggest that there is no primary defect of the insulin receptor per se in terms of insulin binding and autophosphorylation in myotonic dystrophy. The reduction of the insulin binding to erythrocytes and fibroblasts may be caused by the plasma membrane abnormality that affects the binding affinity of the receptor.

Adult↗
PubMed1990

[Alternating non-cross resistant multi-drug chemotherapy against malignant lymphoma (CAMBO-VIP)--consideration of the dose intensity].

Dose intensity defined as the amount of drug used per unit time, expressed as mg/m2/week, was reported to be a significant determinant of antitumor activity of single or combined drugs in cancer chemotherapy. We formulated a 12 week high dose intensity chemotherapy (CAMBO-VIP) for the treatment of advanced non Hodgkin's lymphoma with aggressive histology. The treatment consists of weekly alternate administration of myelosuppressive and non-myelosuppressive agents. Doxorubicin was administered every other week in combination with either cyclophosphamide, etoposide or ifosfamide. On the weeks in between, non-myelosuppressive vincristine was given with either methotrexate with leucovorin rescue or bleomycin. Prednisolone was given for the first and the last 4 weeks. Dose reduction and treatment delay were kept minimal for the purpose not lowering dose intensity. As of February 1990, 32 patients (pts), median age 52, entered the study, 29 of whom completed the treatment. There were 3 incomplete cases, in which 2 were due to interruption of the treatment at 5 and 6 weeks, respectively and 1 due to a half dose given because of the old age. CR was obtained in 29 pts (90.6%). Relapse occurred in 3 (10.4%) with the median follow-up of 12 months. Two year disease-free survival (DFS) was estimated to be 76.0% for all the patients and 83.9% for CR patients. Toxicity of CAMBO-VIP was moderate with no chemotherapeutic death. Myelosuppression was severe but of short duration, requiring virtually no dose reduction. Treatment delay was 3 days, median, and maximally 28 days. The average actual dose intensity calculated from given amount of drugs and treatment duration was as high as 90% of the protocol dose intensity. Dose intensity of CAMBO-VIP protocol is highest, equaling to that of MACOP-B, among representative series of reported lymphoma protocols. A highly significant correlation was observed between 9 drug relative dose intensity and DFS of the patients treated with each protocol. Significance of dose intensity as an independent prognostic factor, however, should be determined, by a prospective carefully designed stratified randomized studies.

Aged↗