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Biomedical subjects

S Asada

Publications and source records attributed to S Asada.

At least 127 records · Page 7Linked to original sources
PubMed1979

Deoxyribonucleic acid strand breaks during drying of Escherichia coli on a hydorohobic filter membrane.

Cells of Escherichia coli mounted on a hydrophobic filter membrane were dried under various vapor pressures. A mutant defective in deoxyribonucleic acid repair (uvrA recA) was more sensitive to drying at a water activity of 0.53 or below than the parent strain but not at a water activity of 0.75 and above. Sucrose gradient studies showed that single- and double-strand breaks of deoxyribonucleic acid occurred at a water activity of 0.53 or below, but no breaks could be observed at a water activity of 0.75 or above. These results were observed in all cells rehydrated with 0.03 M tris (hydroxymethyl) aminomethane-hydrocholoride buffer solution at 0 or 37 degrees C, in the presence or absence of oxygen, with saturated water vapor or with a hypertonic solution followed by a gradual dilution. Freezable water was detected in the cells only at a water activity above 0.75 by differential scanning calorimetry. Removal of unfreezable water of cells in the drying, therfore, might induce deoxyribonucleic acid strand breaks.

DNA Repair↗
PubMed1979

The effect of phenoxybenzamine on the pulmonary vascular bed in surgically corrected ventricular septal defect associated with pulmonary hypertension.

From 1971 to 1977, a total of 43 cases with ventricular septal defect associated with pulmonary hypertension (VSD + PH), ranging from 3 months to 6 years of age, underwent VSD closure using cardiopulmonary bypass with a prophylactic dose of phenoxybenzamine (POB) 1 mg/Kg. Twenty of these cases are included in the present study of the effect of POB on pulmonary hypertension. The ratios of pulmonary to systemic arterial pressures (Pp/Ps) and vascular resistances (Rp/Rs) were measured before, immediately after and 1 month after VSD closure. In all cases, the Pp/Ps before VSD closure was larger than 0.75. Both Pp/Ps and Rp/Rs markedly decreased immediately after VSD closure but rose again 1 month thereafter. These results suggest the possibility of pulmonary vasodilating effect of POB, which could be potentially useful in relieving the right ventricular load in the early postoperative period. The over all mortality was 3 out of 43 cases including 2 late deaths.

Blood Pressure↗
PubMed1979

Lung pathology in infants with severe pulmonary hypertension and cardiac disease.

Lung biopsy specimens were taken from 39 infants younger than 12 months of age with congenital heart disease and severe pulmonary hypertension (Pp/Ps greater than or equal to 0.75) accompanied by respiratory distress. The pathological change in lung specimens and clinical courses were compared. These 39 infants underwent surgical treatment of patent ductus arteriosus (PDA), seven patients; ventricular septal defect (VSD), 13 patients; and complex heart anomaly, 19 patients. The common pathological findings of the lung specimens taken from these infants were lymphoid cellular infiltration and thickening of the alveolar septum, which we have called "septitis" in the present study. In most cases pulmonary vascular obstructive change was within Grade 2 of the Health-Edwards criteria. Septitis was classified into three categories: mild, moderate, and severe. Only three of the 19 infants with severe septitis survived postoperatively, whereas 10 of the 12 infants with moderate septitis and all eight with mild septitis could be successfully weaned. The cause of septitis remains unidentified. We have found the patient's age and pulmonary hypertension to be closely related to the grade of septitis in this study. Septitis plays a much more important role than pulmonary vascular obstructive change in the prognosis of pulmonary hypertensive heart disease in early infancy.

Biopsy↗
PubMed1978

Choledochal cyst. Etiological considerations and surgical management in 22 cases.

In a 14-year period from 1962 to 1976, there were 22 cases of choledochal cyst treated by two different approaches: choledochocystenterostomy to the duodenum in three and to the jejunum in a Roux-en-Y operation in four cases, and excision of the cyst with hepaticojejunostomy in 14 and with end-to-end anastomosis of the common bile duct in one case. There was one death in each group. In five cases, direct cholangiography, either operative or endoscopic, demonstrated a reflux of the contrast material from the biliary system to the pancreatic duct. In four cases, the amylase level of the cystic content was elevated, ranging from 182 to 50,820 Somogyi units. A reflux of the pancreatic juice into the biliary system was thought to be a possible cause of choledochal cyst. Excision of the cyst with hepaticojejunostomy in a Roux-en-Y operation seems to be the treatment of choice from the aspects of cholangitis, malignant change, and termination of the pancreatic reflux to the biliary system.

Adolescent↗