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Biomedical subjects

F H Rola

Publications and source records attributed to F H Rola.

23 records · Page 2Linked to original sources
PubMed1972

Adenosine triphosphatase associated with adenosine triphosphate-dependent deoxyribonuclease (recB-recC enzyme-E. coli-ATP to phosphodiester hydrolysis ratio-DNA-dependent ATPase activity).

An ATPase activity that is completely dependent on DNA is associated with the ATP-dependent DNase (recB-recC enzyme) purified from Escherichia coli. There is a strong correlation between the ATPase and the DNase activities under various assay conditions. With E. coli DNA as substrate, 8-9 molecules of ATP are hydrolyzed to ADP and inorganic phosphate for every phosphodiester bond hydrolyzed by the DNase. The possible functional relationship of the ATPase and DNase activities is discussed.

Acrylamides↗
PubMedDate not supplied

A plethysmometric method for gastric compliance studies in anesthetized rats.

A new method to study gastric volume by plethysmography is presented. Twenty male Wistar rats (250-300 g) were fasted for 24 h. After anesthesia with urethane (1.2 g/kg, i.p.), a tracheostomy was performed, and cervical vessels were cannulated. A balloon catheter was introduced per os and positioned in the proximal stomach. The opposite end of the catheter was connected to a reservoir (volume = 30 ml; inside diameter = 2.5 cm), coupled to a plethysmometer. A standard ionic solution was used to fill the balloon ( approximately 3.0 ml) and the communicating vessel system. Calibration experiments (n = 5) displayed a strong (r(2) = 0.99) correlation between graded balloon-volume changes and plethysmometric recordings. Because distending pressure of the stomach remained constant, the balloon-volume recordings were taken as gastric compliance index. Gastric volume changes, mean arterial pressure, and heart rate of animals of control and experimental groups were monitored for 90 min. The data were analyzed by analysis of variance and the Student-Newman-Keuls test. In control animals (n = 5), no significant changes on gastric volume and hemodynamic values were found. Experimental animals were treated with either yohimbine (n = 5) or bethanechol (n = 5) i.v. injections. The rats received consecutive doses of yohimbine (0.5 and 1 mg/kg) or bethanechol (1.5 and 3 microg/kg), 30 min apart. Both doses of each treatment transiently induced hypotension and bradycardia (p < 0.05). Yohimbine treatment (1 mg/kg) increased gastric volume by half (p < 0.05), whereas bethanechol (3 microg/kg) decreased it by 35% (p < 0.05). In summary, this work shows a suitable method to directly assess gastric compliance in anesthetized rats.

Adrenergic alpha-Antagonists↗