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Biomedical subjects

A Asada

Publications and source records attributed to A Asada.

At least 91 records · Page 5Linked to original sources
PubMed1987

Enhanced responsiveness to parathyroid hormone and induction of functional differentiation of cultured rabbit costal chondrocytes by a pulsed electromagnetic field.

Pulsed electromagnetic fields promote healing of delayed united and ununited fractures by triggering a series of events in fibrocartilage. We examined the effects of a pulsed electromagnetic field (recurrent bursts, 15.4 Hz, of shorter pulses of an average of 2 gauss) on rabbit costal chondrocytes in culture. A pulsed electromagnetic field slightly reduced the intracellular cyclic adenosine 3',5'-monophosphate (cAMP) level in the culture. However, it significantly enhanced cAMP accumulation in response to parathyroid hormone (PTH) to 140% of that induced by PTH in its absence, while it did not affect cAMP accumulation in response to prostaglandin E1 or prostaglandin I2. The effect on cAMP accumulation in response to PTH became evident after exposure of the cultures to the pulsed electromagnetic field for 48 h, and was dependent upon the field strength. cAMP accumulation in response to PTH is followed by induction of ornithine decarboxylase, a good marker of differentiated chondrocytes, after PTH treatment for 4 h. Consistent with the enhanced cAMP accumulation, ornithine decarboxylase activity induced by PTH was also increased by the pulsed electromagnetic field to 170% of that in cells not exposed to a pulsed electromagnetic field. Furthermore, stimulation of glycosaminoglycan synthesis, a differentiated phenotype, in response to PTH was significantly enhanced by a pulsed electromagnetic field. Thus, a pulsed electromagnetic field enhanced a series of events in rabbit costal chondrocytes in response to PTH. These findings show that exposure of chondrocytes to a pulsed electromagnetic field resulted in functional differentiation of the cells.

Alprostadil↗
PubMed1984

Torsade de pointes induced by N-acetylprocainamide.

N-Acetylprocainamide (NAPA), a class III antiarrhythmic drug, caused torsade de pointes in a 72 year old woman who had this arrhythmia on two previous occasions while being treated with quinidine and disopyramide. Initial evaluation with an intravenous infusion of NAPA indicated a favorable antiarrhythmic response. The QTC interval was prolonged, but the 2.4 ms/microgram per ml incremental QTC interval lengthening caused by NAPA was not greater than usual. During subsequent oral therapy with NAPA, torsade de pointes developed at plasma levels of this drug that appeared to be well tolerated during the initial evaluation.

Acecainide↗
PubMed1984

Urea distribution kinetics analyzed by simultaneous injection of urea and inulin: demonstration that transcapillary exchange is rate limiting.

The kinetics of urea and inulin were studied after simultaneous i.v. injection in six anesthetized dogs. The distribution of both compounds was characterized by a three-compartment model. The initial volume of urea distribution averaged 2.21 +/- 0.39 liters (+/- S.D.) and was similar to the expected volume of intravascular space. Although the 0.66 +/- 0.05 liters/kg of total volume of urea distribution corresponds to total body water, transcapillary exchange between intravascular space and rapid and slow equilibrating interstitial fluid spaces is the rate-limiting step in urea distribution and accounts for the three-compartmental structure of the system used to model the distribution kinetics of both urea and inulin. The free-water diffusion coefficient ratio of urea and inulin and the intercompartment clearances calculated after the simultaneous injection of these compounds were used to estimate blood flows to the fast and slow equilibrating interstitial fluid compartments. The sum of these flows averaged 97% of measured cardiac output (range, 83-113%) and was not significantly different from cardiac output. These studies suggest that the rate of urea removal during dialysis may be affected by hemodynamic factors, as we have shown previously for drugs.

Animals↗
PubMed1982

Selective bronchial suctioning in the adult using a curve-tipped catheter with a guide mark.

Our results of previous and successive studies indicate that torque control of curve-tipped catheters is easily accomplished by placing a guide mark on the catheter. Thus, a guide mark was made on a curve-tipped 14 FG Portex suction catheter using a felt pen. The efficacy of selective bronchial suctioning using this catheter was studied in 50 patients. Directed suctioning of the left and right bronchial passages was performed in each patient 3 times and once, respectively, with the head in the midline position. The success rate of left bronchial suctioning was 92% (138/150 attempts) and success in right bronchial suctioning 98% (49/50 attempts). The curve-tipped catheter with a guide mark significantly improved the success rate of left bronchial entry over the previous rate from 50% to 92%.

Bronchi↗
PubMed1980

Evaluation of selective bronchial suctioning in the adult.

In the present study, the highest success rate in suctioning of the left main bronchus was achieved when curved-tip catheters of both Portex (40%) (Portex Limited, Hythe, Kent, England) and Rüsch (50%) (Willy Rüsch Gmph & Co. KG, West-Germany) were inserted with the patient's head in the midline position. The second most successful rate in reaching the left main stem bronchus occurred when the head was turned to the right using straight catheters of both Portex (31%) and Rüsch (29%). The third but lesser success rate in suctioning the left main stem bronchus was achieved with the head turned to the right, using curved-tip catheters of both Portex (25%) and Rüsch (23%). the lowest success rate in suctioning the left main stem bronchus was with the head in the midline position using straight catheters of both Portex (19%) and Rüsch (15%). The possible factors which influence success or failure to introducing suction catheters into the bronchi selectively were discussed.

Bronchi↗
PubMed1980

Hemodiafiltration with sodium concentration-controlled dialysate.

When hemofiltration and hemodialysis are compared, the former is more effective in removing larger substances, whereas the latter is superior in removing small substances. We consider hemodiafiltration, in which the advantages of the two treatment methods can be adopted, as the most effective and practical method. In the studies of hemodiafiltration, we demonstrated that disequilibrium syndrome associated with the treatment can be prevented by employing a high sodium concentration in the dialysate. The dialysate was successfully used for treating intracellular overhydration. However, it could not be used without causing adverse effects such as thirst in patients whose intracellular overhydration had already been treated and resulted in increase in their body weight. However, these patients were treated successfully by decreasing the high sodium concentration gradually or in a stepwise manner.

Blood↗
PubMed1979

Induction by parathyroid hormone of ornithine decarboxylase in rabbit costal chondrocytes in culture.

The activity of ornithine decarboxylase (ODC) in rabbit costal chondrocytes in culture markedly increased after addition of parathyroid hormone (PTH), reaching a maximum 4 to 5 h after PTH addition. The effect of PTH was dose-dependent both in the presence and absence of fetal calf serum. Addition of cycloheximide or actinomycin D prevented the induction of ODC by PTH. Calcitonin, 1,25-dihydroxyvitamin D3, and vitamin A had no stimulatory effect on the activity of ODC, and did not inhibit the induction of ODC by PTH, when added with PTH.

Animals↗