The effect of portacaval transposition of hepatic cholesterol-7alpha-hydroxylase activity in the rat.

Portacaval anastomosis in the rat results in an increase in the activity of the liver microsomal cholesterol-7alpha-hydroxylase enzyme system. The increase in the activity of this oxygenase occurs despite a decrease in the total amount of cytochrome p450 in the liver microsomes after portacaval anastomosis. It is possible to increase further the activity of the cholesterol-7alpha-hydroxylase enzyme in these portacaval shunted animals by feeding them on a diet containing a bile salt sequestering agent. This suggests that one of the factors influencing the activity of the liver microsomal cholesterol-7alpha-hydroxylase enzyme may be the concentration of bile salts reaching the liver from the blood plasma. Portacaval anastomosis in the rat tended to achieve a small decrease in the plasma cholesterol concentration.     

Role of aldosterone in the initial stage of 2 forms of experimental vasorenal hypertension]

The role of rat adrenal mineralocorticoid function in the development of experimental reno-vascular hypertension was studied. Na-retention action of aldosterone was blocked by means of verospiron. Daily excretion of aldosterone proved to be significantly increased in rats with unilateral stenosis of the renal artery (the contralateral kidney was intact). In ischemia of the only kidney there was seen no change in the activation of adrenal mineralocorticoid function. Administration of verospiron strongly suppressed the development of the first form of reno-vascular hypertension and had no effect on the blood pressure in rats with stenosis of the only kidney.     

Hemodynamic aspects of the hypotensive action of captopril

Captopril was tested in acute experiments on anesthetized cats subject to cardiopulmonary bypass. The drug was shown to reduce total peripheral vascular resistance and to increase vascular bed capacity.     

Effect of the alpha-adrenoblocker pyrroxan on systemic hemodynamics in puppies and dogs with vasorenal hypertension]

Vasorenal hypertension was induced in 2--3-month-old puppies and adult dogs by stricture of both renal arteries. 1.5 mg/kg of pyrroxan was injected intravenously 3 and 14 days later. A reduction of increased arterial pressure was noted both in adult dogs and in puppies, to the subnormal level in the latter. Hypotensive effect of the preparation was connected in adult animals with diminution of the general peripheral vascular resistance and in puppies, besides, with reduction of cardiac output. Pyrroxan injection was accompanied in all the animals with tachycardia, reduction of the phase of isometric contraction and activation of myocardial contractility.     

The use of Doppler ultrasound of the renal arteries for the diagnosis of vasorenal hypertension at the outpatient stage]

Ultrasonic dopplerography of the renal arteries was used to improve the differential diagnosis of arterial hypertension before hospitalization. Dopplerograms of the renal arteries of normal subjects were characterized by almost symmetrical parameters of the blood stream. In patients with vasorenal hypertension a marked asymmetry of the blood stream was seen with its reduction and qualitative changes in the dopplerogram on the side of the stenosed renal artery, that was confirmed by angiographic findings. Chronic pyelonephritis was dopplerographically characterized by hemodynamically insignificant asymmetry of the blood stream in the renal arteries with its reduction on the side of the involved kidney. In essential hypertension the type of asymmetry of blood stream parameters in the renal artery seemed similar to that in normal subjects.     

Surgical transposition of the atria: A new procedure for repairing transposition of the great vessels

The proposed procedure consists of interchanging the positions of the atria by means of an incision used in heart transplantation. After frontal sectioning of the atrial body, the heart is turned up on its pedicle, the interatrial septum is divided in its posterior part, and the vena cavae are extensively freed from their mediastinal and diaphragmatic attachments. The posterior parts of the atria can then be transposed: the right atrium and vena cava are repositioned to the left of the left atrium, and a new septum is constructed by joining the external atrial walls. The heart can then be replaced and the walls of the transposed atria repaired by edge-to-edge sutures. Cadaver experiments have indicated that this procedure is applicable in infants and young people. Casts and radiologic examinations have shown no strictures in the vena cavae, and the possibility of postoperative arrhythmias has been evaluated by means of electrocardiographic studies in dogs surviving for long periods after heart autotransplantation.     

Glucose tolerance and insulinemia in patients with hepatic cirrhosis and portal hypertension treated by portacaval anastomosis]

Development of diabetes mellitus is a common complication of side to side porta-caval anastomosis (PCA). Five patients with liver cirrhosis and portal hypertension have been studied with intravehous (IVGTT, 0,5 g/Kg B.W.) and oral (OGTT, 1 g/Kg B.W.) glucose tolerance tests before and three weeks after PCA. Fasting plasma glucose was 84 +/- 7 before and 87 +/- 3 mg/dl after PCA. Fasting IRI increased from 17 +/- 3 to 31 +/- 6 microU/ml. The pattern of plasma glucose and IRI response to IVGTT did not change after PCA. Plasma glucose resonse to OGTT after PCA showed only an earlier rise at 60 instead of 90 minutes, whereas IRI resonse (area under the insulin curve) was significantly enhanced (from 12.4 to 19.8 U/l, p < 0.05). These data suggest a role of gut polipeptides in determining hyperinsulinemia and insulin resistence in PCA patients.     

A family study in transposition of the great vessels and in tricuspid atresia

Summary A group of 186 propositi with transposition of the great vessels (TGV) and 33 propositi with tricuspid atresia (TA) were studied. Data were obtained from hospital records and complemented by questionnaires and in part by personal interview and clinical examination. The main results were among sibs of propositi with TGV an increased incidence of TGV (0.0135±0.0054) and of congenital heart disease in general (0.0495±0.0103) (K=0, r_min=1). Among 92 sibs of propositi with TA only one with patent ductus arteriosus was found. The sex ratio of the propositi with TGV was 1.95. There was also noted a highly abnormal sex ratio among sibs of parents of patients with TGV in part confirming the findings of Knox.A male excess was found in paternal and maternal sibships and was also present in sibships of propositi. Data about seasonal distribution were inconclusive as were data about consanguinity of parents. No parental age or birth order effect was found in either group.This work has been carried out in part during the author's stay at the Genetic Clinic of the Children's Memorial Hospital, Dept. of Pediatrics, Northwestern University Medical School (Prof. D. Y.-Y. Hsia, M.D.). Data have been collected in collaboration with Dr. M. H. Paul, director of the Dept. of Cardiology of the Children's Memorial Hospital, Willis J. Potts Children's Heart Center. The author was supported in part by a grant from the US Public Health Service, National Institutes of Health and a Fulbright Travel Grant.     

Ventrobulbular hypotensive action of muscimol]

Muscimol, a rigid analogue of GABA has been injected in the CNS of urethane anesthetized, normotensive cats. Injected either intracisternally (1 or 2 microgram/kg, 0.05 ml) or directly by microinjection in a restricted ventrolateral region of the brain stem (0.5 or 1 microgram/kg, 0.5 microliter), muscimol induced hypotension and bradycardia. These central cardiovascular effects of muscimol were antagonized by bicuculline, a "specific" GABA antagonist agent. These data emphasize the involvement of gabergic mechanisms in the central cardiovascular control, at least in the ventrolateral part of the medulla oblongata.