The fact that pulmonary arterial pressure alters very little with considerable changes in cardiac output makes pulmonary haemodynamics an interesting study. It has a practical importance in that the blood leaving the lungs controls the input to the left auricle and thus the output of the left ventricle; furthermore, the pulmonary vascular bed has been considered to act as a blood reservoir (Hamilton & Morgan, 1932; Lagerlof, Eliasch, Werko & Berglund 1951). Pressure-flow curves combined with measurements of changes in pulmonary blood volume form a means of investigating the behaviour of the pulmonary blood vessels under changing conditions. Studies of this nature have been made in isolated perfused lungs of dogs by Laux (1930), Daly (1928, 1938), Wezler & Sinn (1953), by Jarisch & van Wijngaarden (1926) Since information on the pulmonary circulation in cats appears to be scanty it was thought justifiable to perform more experiments. Isolated lungs were chosen as test preparations because of the difficulties involved in making measurements in the whole animal.
METHODSIsolated lungs from cats (1.8-4.0kg) were perfused through the pulmonary artery with the animal's own heparinized blood (Liquemin, Roche, 1000 u./ 100 ml.), using a Dale-Schuster pump (48 rev/min). The blood was collected under chloralose anaesthesia (0-1 g/kg intraperitoneally) and sometimes 10-30 ml. dextran (Intradex, Glaxo) was added to it to make sufficient volume. The venous outflow was collected from the left auricle into a reservoir which fed the pump. Ventilation was by positive pressure using a Starling 'Ideal' pump (15 rev/min). The maximum intratracheal pressure was kept constant at 5-10 cm H20 during an experiment, and changes in the volume of air entering the lungs were measured by the method of Konzett & Rossler (1940). Pulmonary arterial pressures were read on a manometer filled with 0-9 % NaCl solution and recorded by
SUMMARY A 47-year-old woman was cured of hypokalaemia and recurrent paralysis by the excision of an adrenal adenoma. Hypertension was initially ameliorated but was not cured. Suppression of plasma renin activity was abolished when the adenoma was excised. Repeated measurement of plasma corticosteroids before operation showed a slight increase in aldosterone and normal plasma concentrations of deoxycorticosterone, corticosterone, and cortisol. No evidence of excess mineralocorticoid was obtained from measurement of the electrolyte composition of colonic fluid or of rectal potential difference, although both these variables responded normally to salt depletion and exogenous aldosterone. The diagnostic importance of the paradoxically normal colonic measurements is emphasized and the possibility is considered that the adenoma may have secreted an unidentified hormone.
the complete saturation of the carbiinculous mass, no pain occurred, my patient going about his ordinary labor without discomfort. It is now but a year since I treated another case in a similar manner, with
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