Biomedical subjects
N Walde
Publications and source records attributed to N Walde.
Improved haemodynamics but reduced arterial blood oxygenation, at rest and during exercise after long-term oral prazosin therapy in chronic cor pulmonale.
The effect of vasodilator therapy in chronic obstructive lung disease with pulmonary hypertension was evaluated in eight patients during oral prazosin therapy (2-10 mg day-1). After one week, prazosin reduced mean pulmonary artery pressure and pulmonary and systemic vascular resistance, and increased cardiac index both at rest and during exercise. Similarly improved haemodynamics were observed after two months of therapy. Arterial PO2 and oxygen saturation fell significantly after two months both at rest and during exercise, but were not changed after one week. Lung function tests were not altered by prazosin. Thus, although prazosin improves the haemodynamics in patients with chronic obstructive lung disease, caution is advised in long-term therapy since prazosin worsens the arterial blood oxygenation.
The effect of secretin on gastric H+ and pepsin secretion and on urinary electrolyte excretion in man.
After an initial 40-min period of gastric suction, the gastric juice was collected for 12 30-min periods from 8 healthy young male students. During the first hour 30-min periods saline alone was infused, whereafter secretin in a dose of 0.05 CU/kg and h was given in the middle four 30-min periods and in a dose of 0.25 CU/kg and h for the final four 30-min periods. Urine was collected in three 2-h portions corresponding to each change of infusion procedure, and blood for determination of plasma secretin by a radioimmunoassay procedure was drawn at hourly intervals. Plasma secretin was unaltered both during the saline infusion and during the infusion of secretin in a dose of 0.05 CU/kg and h but rose during the infusion of 0.25 CU/kg and h. Compared with the mean 30-min output in the initial saline control period, gastrin pepsin secretion rose significantly in the third 30-min period, and gastric H+ output fell significantly in the fourth 30-min period of infusion of secretin in a dose of 0.05 CU/kg and h. During the higher secretin dose gastric output could not be evaluated owing to duodenogastric reflux. Urinary sodium excretion increased only during the infusion of secretin in a dose of 0.25 CU/kg and h, whereas secretin showed no effect on the urinary outputs of water, potassium, and solutes. The results of the present study indicate that secretin may play a physiological role in the regulation of gastric H+ and pepsin secretions, whereas its diuretic effect probably is a pharmacological effect only.