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Biomedical subjects

T Kawada

Publications and source records attributed to T Kawada.

At least 199 records · Page 11Linked to original sources

Level of preadipocyte growth factor in rat adipose tissue which specifically permits the proliferation of preadipocytes is affected by restricted energy intake.

We previously reported the presence of a protein growth factor in rat adipose tissue which specifically permits the proliferation of 3T3-L1 and Ob1771 preadipocytes [Biochem. Biophys. Res. Commun. 1990;171:905-912, ref. 1] and which is hereinafter referred to as PAGF (preadipocyte growth factor). In this study, the effects of long-term restricted energy intake on the PAGF activity in rat epididymal and perirenal adipose tissue toward 3T3-L1 preadipocytes were investigated. When rats were subjected to restricted energy intake for three weeks, PAGF activity increased with energy intake. The body weight, epididymal and perirenal fat depot weights and glycerol 3-phosphate dehydrogenase activity also increased with the energy intake, whereas the lactate dehydrogenase activity remained almost constant in all energy intake groups. These results suggest that the PAGF in fat depots functions in response to energy intake and contributes to the de novo formation of adipocytes and the growth of adipose tissue. This factor may provide a useful tool for further elucidation of the relationship between energy storage in adipose tissue and adipose tissue development.

3T3-L1 Cells↗

Relationship between subjective sleep rating and objective sleep parameters: a case study.

The subjective sleep of a male subject was related to 22 objective polygraphic sleep parameters on 39 experimental nights. Subjective sleep was rated by the sleeper himself as "good," "moderate," or "poor" upon arising, for 10, 24, and 5 nights, respectively. Differences in the 22 sleep parameters for these three ratings were examined, and poor sleep showed a significant increase in stage W (waking), an elongation of sleep latency, a decrease in mean sleep depth during the night and 2 hr after going to bed, a decrease in integrated value of sleep depth during the night, an increase in the gradient and decrease in the intercept of regression line of sleep depth against time, and a shortening of total sleep time. The average delta wave percentage per epoch was greater for a subjective rating of "moderate" than for the other groups. Canonical discriminant analysis was conducted using 16 sleep parameters, and the overall correct identification rate of three subjective sleep ratings by the objective sleep parameters was 89.7%. Variables of the first or second axis with large standard coefficients were stages 1, 2, REM (rapid eye movement), integrated voltage of electromyogram, and sleep latency. From the above two sets of analyses, sleep latency was the most useful parameter for predicting subjective sleep.

Adult↗

Effect of some factors on sleep polygraphic parameters and subjective evaluations of sleep.

In this study a bedroom in a noisy area and one in a quiet area were used to investigate the effects of road traffic noise on sleep. Subjective sleep and objective sleep polygraphic parameters were obtained from subjects sleeping in each bedroom. Differences in these parameters at the two locations were compared. The experimental environment differed from those formerly used. The authors thus examined the influences on sleep of covariates in terms of subject differences, age differences, sex difference, differences in the order of experimental nights, set differences, and noise differences. From Spearman's rank correlation coefficient and two-way analysis of variance, subject and age differences were found to have greater effects on many sleep parameters than noise differences. Principal factor analysis was done for young and old subjects separately. The sixth factor was related to noise differences. The sleep parameter common to young and old subjects of the sixth factor was %REM.

Adult↗

Relationship between myoglobin contents and increases in cyclic GMP produced by glyceryl trinitrate and nitric oxide in rabbit aorta, right atrium and papillary muscle.

Effects of glyceryl trinitrate (GTN) and nitric oxide (NO) on the cardiac functions and myocardial cyclic GMP (cGMP) contents were examined in comparison with those in the aorta and correlated with myoglobin (an inhibitor of soluble guanylate cyclase) contents using the preparations isolated from the reserpinized rabbit. GTN (10(-10)-10(-4) mol/l) produced a dose-dependent relaxation in the aorta. However, this compound exerted no effect on the rate of the spontaneous beat of the right atrium and the contraction of the papillary muscle. A transient and significant increase in cGMP was observed in the aorta with GTN (3 x 10(-6) mol/l). Although the increase was also observed in the right atrium, it was much smaller. No definite change was observed in papillary muscle. Increases in cGMP produced by NO (3 x 10(-6) mol/l) were larger and significant in all tissues; (AUCcGMP(GTN)/AUCcGMP(NO)) ratio was 30.1 for the aorta, 65.0 for the right atrium and 16.3% for the papillary muscle. Although higher concentrations of NO were necessary in the right atrium and papillary muscle to induce increases in cGMP, no differences were noted in the three tissues as regards the maximum accumulation of this substance. Furthermore, kinetic analysis of NO-induced increases in tissue cGMP indicated no marked difference in the production rate among the three tissues, while the rate of elimination of cGMP was lower in the aorta than in the atrium or the papillary muscle. The increases in cGMP observed in these three tissues were inversely related to the contents of myoglobin in respective tissues.(ABSTRACT TRUNCATED AT 250 WORDS)

3',5'-Cyclic-GMP Phosphodiesterases↗

Hemangioma of the upper arm associated with massive hemorrhage in a neonate.

A rare case of an ulcerated hemangioma of the upper arm in a neonate is described herein. Resection of the huge hemangioma, which occupied the axilla and extended down the entire length of the upper arm, was necessary due to massive hemorrhage from the ulcer and progressive heart failure caused by the arteriovenous fistula in the hemangioma. After complete resection of the hemangioma, extensive defects of the skin and subcutaneous tissue were replaced by a skin flap closure technique which involved considerable difficulty. However, the arm gradually recovered its size and function with good wound healing. The present case illustrates that rapid surgical intervention may be required to prevent clinical deterioration in such cases.

Arm↗

Time-course of recovery of atrial contraction after cardioversion of chronic atrial fibrillation.

We aimed to study the time-course of recovery of atrial contraction after cardioversion of chronic atrial fibrillation (duration of more than 3 months) to sinus rhythm. Using M-mode, two-dimensional and pulsed Doppler echocardiography, we determined left atrial (LA) and ventricular (LV) dimensions, peak velocities, and velocity-time integrals of early and atrial filling velocity-time profiles in both LV and right ventricular (RV) inflows (peak E and peak A, Ea and Aa). Results of the LA and LV functions in seven elderly patients (an initial study group) were as follows. The extent of the LA dimensional reduction resulting from atrial contraction was significantly increased up to 5-8 weeks compared with values 0-1 day after cardioversion [from 1.3 +/- 0.8 (mean +/- SD) mm to 3.9 +/- 1.1, P < 0.01]. In conjunction with the progressive increase in peak A, the ratio of peak E to peak A (peak E/A) was significantly decreased and reached a plateau at 5-8 weeks (from 1.93 +/- 0.59 to 0.67 +/- 0.11, P < 0.01). LV fractional shortening was increased significantly 5-8 weeks after cardioversion (from 0.20 +/- 0.06 to 0.29 +/- 0.05, P < 0.01). Since a large part of the improvement in LA contraction was expected to occur in an early stage after cardioversion, we studied eight additional patients more frequently in the early stage (an additional study group). Furthermore, we studied the time course of LA and right atrial (RA) contractions.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

Usefulness of sodium chloride as a nondiffusible indicator in the measurement of extravascular lung thermal volume in dogs.

The authors examined the usefulness of sodium chloride as a nondiffusible indicator during the first passage through dogs' lungs, before and after increased-permeability pulmonary oedema produced by an intravenous injection of alloxan. With an injection of a mixture of ice-cold 3 per cent sodium chloride and indocyanine green dye (a nondiffusible reference indicator), the authors simultaneously recorded three dilution curves from the aortic root: dye dilution, thermal and blood electrical conductivity dilution curves in six dogs. The mean transit time of sodium chloride in the conductivity dilution curve was significantly different from, but fairly equal to, that of indocyanine green dye (6.2 +/- 1.4 s (mean +/- SD) against 6.5 +/- 1.4 s (p < 0.01) in the baseline period, and 7.6 +/- 1.9 s against 8.4 +/- 2.1 s (p < 0.01) in the oedema period, respectively). The calculated extravascular lung thermal volume with the thermal and conductivity dilution method (Y, ml kg-1) correlated well with the gravimetrically determined extravascular lung mass in a total of 12 dogs, including six other dogs without intervention (x, g kg-1) (y = 0.72 x +3.03, r = 0.96). The authors conclude that sodium chloride is useful as a nondiffusible indicator in the first passage through the lungs, and that the thermal and conductivity dilution method is also useful for measuring extravascular lung water mass.

Animals↗

Sulfite suppresses transducer function of the carotid sinus baroreceptor.

The purpose of this study was to examine the effect of sodium metabisulfite (MBS) solution on the transducer function of the carotid sinus baroreceptor. In anesthetized dogs with vagotomy, we vascularly isolated the carotid bifurcation to load a pressure on the carotid sinus baroreceptor. As the pressure load, we used a slow ramp increase (0.7 mmHg/s) in intracarotid sinus pressure (ICSP). The response of carotid sinus nerve activity (CSNA) to the slow ramp increase in ICSP was suppressed when the isolated carotid sinus was filled with the MBS solution of 10(-2) M. This suppressive effect of MBS solution on the response of CSNA was reversible. The MBS solution had no effect on the pressure-volume relationship of the arterial wall of the isolated carotid sinus and on the impulse conduction of carotid sinus nerve. This suppressive effect of the MBS solution of 10(-2) M was weakened by introducing oxygen gas into the solution to lose the total sulfite anions in the solution. These results suggest that: (1) the MBS solution reversibly suppresses the transducer function of the carotid sinus baroreceptor; (2) the target construction of the carotid sinus region that was affected by the MBS solution might be the carotid sinus baroreceptor nerve terminal where ICSP was transduced into carotid sinus nerve firing; and (3) the suppressive effect might be provoked by the sulfite anions in the MBS solution.

Animals↗

Correction for apparent prolongation of mean transit time resulting from response time in a thermodilution system.

We investigated a method of correcting an apparent prolongation in the measured mean transit time (MTT), resulting from the response time of the thermodilution system. We measured the mean response times (MRT) for five commercially available thermistor-tipped catheters by recording their step function response curves. MRT is the sum of the time from the point of step change to the point of the first detection of change in temperature (latency time) plus the time from the first detection to the point of 63.2% of full response (time constant). By using a flow loop model filled with saline through a mixing chamber, we recorded pairs of thermodilution curves simultaneously with pairs of catheters, and studied the influence of MRT on MTT over the constant flow rates of 1-6 L/min. The difference in MRT's (delta MRT, second) between a pair of thermodilution systems correlated with the difference in MTT's (delta MTT, second) between a corresponding pair of thermodilution curves, yielding an equation: delta MTT = 1.07 delta MRT = 0.04 (n = 72, r = 0.95), delta MTT/delta MRT = 1.02 +/- 0.18 (mean +/- SD). We conclude that an apparent prolongation of MTT due to response time is removable by subtracting MRT from measured MTT.

Bias↗

Factor structure of Zung self-rating depression scale for workers.

The Zung self-rating depression scale (SDS) was applied to workers of a railway company. A total of 1,784 night-shift workers responded to the questionnaire and 1,394 daytime workers were set as the control group. The average age of the subjects was 39.9. The SDS index decreased with age. A factor analysis was conducted and two factors were obtained having an initial eigen value over 2.0. Factor 1 was the group of 8 positive items, accounting for 18.2%. Factor 2 was the group of 8 depressive items, accounting for 18.1%. Four items including "loss of weight," "constipation," "good appetite," and "partner coping" did not construct a distinct factor. The factor structure of SDS items of the night-shift workers was similar to those of the control group.

Adult↗

In vitro effects of the new calcium antagonist lacidipine.

The effects of lacidipine (LC), a new dihydropyridine calcium antagonist, were studied in comparison with those of nifedipine (NF) in isolated arteries of the dog (DG-AR) and isolated aorta (GP-AO), left and right atria (GP-LA, GP-RA) and ventricular papillary muscles (GP-PM) of the guinea pig. In DG-AR precontracted with high K+, LC and NF produced a concentration-dependent relaxation. The relaxant effect of LC was most potent in the basilar artery. The calcium antagonistic effects of LC was 8.7 and 2.1 times more potent than those of NF, in GP-AO and GP-LA, respectively. Thus, LC was about 4 times more selective towards vascular smooth muscles than NF. The negative chronotropic effects in GP-RA and the negative inotropic effect in GP-PM of NF were more pronounced than those of LC. NF was more potent in inhibiting the action potential of GP-PM than LC both in normal polarized and depolarized conditions. The effects of LC were long-lasting. These results suggest that LC is a potent, highly vascular-selective calcium antagonist with little cardiodepressant effects and as such may be suitable for the treatment of hypertension.

Animals↗

[Changes in the hypnograms of subjects exposed to repeated truck-passing sounds of 45, 50 and 55 dB (A)].

The effects of traffic noise on sleep were evaluated in an experimental room using recorded truck-passing sounds. Peak sound levels were 45, 50, 55 dB (A) at a frequency of one per hour. The background noise of the exposure night was Leq 32.4 dB (A). The subjects were five male students 22 to 23 years old. The sleep stage of each epoch with a 20-second duration was judged visually based on the criteria of a standardized sleep EEG atlas. Data for 10 noise-exposed nights and the same number of control nights were analyzed excluding the first-night data. The sleep parameters used were total sleep time (TST), each sleep stage in minutes, % of sleep stage against TST, sleep efficiency, sleep latency, REM latency, REM cycle, REM duration, waking from sleep, number of stage shifts and subjective sleep as judged by the OSA sleep inventory. The Mann-Whitney test was used for statistical analysis. TST, each sleep stage in minutes, % of sleep stage against TST, sleep efficiency, sleep latency, REM latency, REM cycle, REM duration, waking from sleep and the number of stage shifts of the exposure night did not significantly change compared to those of the control night. However, the sleep latency of the noise-exposed night increased significantly. Subjective sleep measured by five-factor scores and 8 items out of 29 constructing the five-factor scores of the OSA sleep inventory were decreased significantly by noise exposure, indicating deterioration of sleep quality.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Changes in urinary cadmium excretion among pigment workers with improvement of the work environment.

Urinary Cadmium (Cd) levels were measured twice a year from 1986 to 1992 in five workers exposed to cadmium pigment dust. At the end of 1987, the work environment was improved, and urinary Cd was monitored in association with atmospheric Cd. The five subjects were exposed to cadmium dust at maximum concentrations of 0.857 mg/m3 and 0.045 mg/m3, before and after the improvement, respectively. By arbitrarily setting the urinary Cd level of each worker before improvement at 100, the values after improvement ranged from 41.7 to 94.6, yielding no significant difference. Although the environmental level of Cd was decreased by ten-fold or more, no significant decrease in urinary Cd could be detected.

Adult↗

Sleep induction effects of steady 60 dB (A) pink noise.

The effects of 60 dB (A) steady pink noise on sleep induction were studied. Two experiments were conducted. First, 10 night-sleep polygrams of a young male subject were recorded consecutively as controls. Five night polygrams of the same subject were then recorded with exposure to steady 60 dB (A) pink noise. Second, polygrams of four students were recorded using the same noise exposure as in the first experiment. Polygrams for the control night were also recorded. Noise exposure tended to shorten sleep latency, i.e., the values were 4.2 and 9.5 min in the first and second experiment, respectively. The steady 60 dB (A) noise made sleep induction easier.

Adult↗

Ultrastructural substrates for increased lung water content in experimental pulmonary edema.

We examined the relationship between the incidence of ultrastructural changes in the alveolar septum and the extravascular lung water content. Pulmonary edema was induced in 18 mongrel dogs by either dextran (n = 12) or alloxan (n = 6) administration. Six other dogs served as controls. Extravascular lung water content was measured by the thermal-dye double indicator dilution method. Specimens of lung tissue were examined with an electron microscope, and the incidence of 13 types of pathological changes in the alveolar septum was studied. For each type of pathological change, the incidence was correlated with the magnitude of lung water content. The following results were obtained. The incidence of edematous changes in the alveolar interstitium (widening of the interstitial space, and dispersion and disarray of collagen fibres in the interstitial space) was well correlated with lung water content (r = 0.78, p < 0.01, and r = 0.84, p < 0.01, respectively). The correlation was not significant in the remaining types of changes. We conclude that the incidence of the pathological changes in the alveolar septum is increased along with the increase in the content of lung water in both dextran- and alloxan-induced experimental pulmonary edema in dogs.

Alloxan↗

Acute effects of conventional oral dose of disopyramide on left atrial and ventricular functions.

Disopyramide, an antiarrhythmic drug, is known to impair cardiac function, but acute cardiac effects of conventional oral dose of disopyramide are not well known. To examine the extent of acute cardiac effects of daily oral dose of disopyramide, we gave 150 mg of disopyramide to thirteen patients with normal or impaired cardiac function, and observed cardiac function on an hourly basis for 3 hours after baseline period. The serum level of disopyramide reached a therapeutic level (2.0-5.0 micrograms/ml) mostly 1 hour after administration. Doppler-echocardiographically determined left ventricular ejection fraction, and the ratio of the peak early filling velocity to the peak atrial filling velocity in left ventricular inflow velocity remained unchanged throughout the experimental period. Other hemodynamic variables, such as blood pressure and heart rate remained unchanged. We conclude that daily oral dose of disopyramide appears to have no significant effects on cardiac function after administration. Disopyramide seems to be safe and may not be necessarily withheld from patients who need it, when hemodynamic variables are to be measured.

Adult↗