[Significance of angiotensin converting enzyme (ACE) in coronary circulation]. / Importancia de la enzima convertidora de angiotensina (ECA) en la circulación coronaria.

It has been suggested that angiotensin II can be synthesized by other enzymatic pathways besides angiotensin converting enzyme. We evaluated the importance of angiotensin converting enzyme in the coronary circulation during the development of hypertension. Hearts obtained from normotensive (n = 4) and hypertensive rats (n = 4) as well as from hypertensive rats treated with ramipril (n = 4) were stimulated with either angiotensin II or angiotensin I. In a Langendorff perfusion system, angiotensin II induced a greater dose-dependent coronary vasoconstriction in the hearts of hypertensive rats than in normotensive rats (p < 0.05). Furthermore, angiotensin I also induced coronary vasoconstriction, which was greater in the hearts of hypertensive rats than in normotensive rats (p < 0.05). Acute angiotensin converting enzyme inhibition reduced angiotensin I-induced vasoconstriction by 78% in the hearts of normotensive rats and by 82% in the hypertensive rats (p < 0.05), whereas in vivo angiotensin converting enzyme inhibition potentiated angiotensin I-induced vasoconstriction in the hearts of normotensive and hipertensive rats (p < 0.05). Bradykinin receptor's blockade decreased ramiprilat's inhibitory effect on angiotensin I-induced vasoconstriction (p < 0.05). Thus, the present study suggests that, in coronary circulation, angiotensin II synthesis is mainly angiotensin converting enzyme dependent. However, chronic in vivo inhibition could favor induction of other enzymes involved in angiotensin II synthesis. Evenmore, it is possible that the effect of angiotensin converting enzyme inhibition in coronary circulation depends on bradykinin activity.

Zinc and copper concentration in plasma and erythrocytes of patients with chronic renal failure.

Zinc (Zn) and copper (Cu) concentrations were studied in plasma and erythrocytes in patients with chronic renal failure that were on hemo or peritoneal dialysis together with the effect of dialysis treatment on these element concentrations. Plasma Zn was found to be significantly reduced in both groups of patients. On the other hand, erythrocyte zinc levels were higher. This considered more as a metabolic adaptation than as a pathological fact. Plasma Cu increase was observed in hemodialysis patients; however in the group on peritoneal dialysis it was found to be normal. Dialysis did not alter significantly plasma levels in any of these two elements; on the contrary, Zn and Cu levels were decreased in erythrocytes. Ceruloplasmin increased with hemodialysis and decreased with peritoneal dialysis possible due to protein loss resulting in this procedure.

Psychopharmacological properties of the viminol-p-hydroxybenzoate.

The authors studied the viminol-p-hydroxybenzoate (RN: Dividol) through some psychopharmacological tests, making its comparison with neuroleptic and narcotic drugs, with the principal aim of determining if its analgesic action is correlated with a narcotic or psychotropic activity or both of them. The results are discussed.