Studies of 16 adults with nephrotic edema reveal a spectrum of disease, the extremes of which suggest two different pathophysiologic forms. Patients with the "classic" form--vasoconstriction or hypovolemic nephrosis--have high renin and aldosterone levels that are stimulated rather than suppressed by salt-loading but become lower before steroid diuresis. These patients have minimal lesion disease and, perhaps from diffuse capillary damage, tend to have hypovolemia with renin-induced vasoconstriction. Patients with the second, and heretofore undescribed, form--hypervolemic or overfilling nephrosis--have low renin and aldosterone values that rise normally after sodium depletion. Hypertension, mild renal insufficiency, hypervolemia, and steroid resistance with chronic glomerulonephritis are seen histologically. This form appears volume overloaded from impaired renal sodium excretion. In remission of either type, renin system deviations tend towards normal, but one form does not convert to the other. Renin-sodium profiling may help reveal the two forms and predict steroid responsiveness.

To block renin activity, a nonapeptide converting-enzyme inhibitor was given to 65 seated hypertensive patients. Depressor responses occurred only when control plasma renin activity exceeded 2 ng of angiotensin I per milliliter per hour and correlated directly in amplitude with control plasma renin activity and with induced increments in activity (P less than 0.001 for both). Depressor responses, like renin activity, were characteristic for renin subgroups as defined by renin-sodium profiling. Before and after sodium deprivation, the nonapeptide reduced diastolic pressure in all patients with high renin (by 17.3 and 19.8 per cent) and most patients with normal renin (by 9.1 and 17.7 per cent). Low-renin patients remained unresponsive. This enzyme blockade may cause bradykinin accumulation. But if, as seems likely, depressor responses are due to blockade of angiotensin II formation, the results indicate that, irrespective of sodium balance, measurements of plasma renin activity reflect its contribution to blood-pressure maintenance. The results suggest broad participation of the renin system in common forms of hypertension.

No abstract

No abstract

No abstract

Patients on chronic hemodialysis may suffer from a latent protein deficiency, and therapy with essential amino acids has been recommended. In a double blind cross-over study, 13 hemodialysis patients received orally 15.7 g of essential amino acids daily over a 3-month period. Patients were on a liberal diet, containing 1 g of protein per kilogram of body weight per day. Hemodialysis was adequate. Therapy resulted in an increase in urea, uric acid, C3 c complement factor and a fall in C4. Lysine levels increased and phenylalanine fell. Malnutrition could not account for the observed metabolic changes, which are more likely due to uremic metabolic disturbances. A liberal diet of 1 g of protein per kilogram of body weight appears sufficient for patients on hemodialysis. Treatment with essential amino acids offers no advantage.

No abstract

Stroke index obtained by impedance cardiography was compared with values obtained by dye-dilution technique in 17 subjects in 122 determinations made within 2 min of each other. Fifty of these determinations were done after drug administration, postural change, or saline infusion. All values obtained by both methods correlated significantly, but with wide scatter (r=0.49, n = 122, P less than 0.001). The series of determinations within each subject, however, correlated only in one subject significantly; thus any changes of stroke index measured by both techniques were not commensurate. In addition, the impedance stroke index values were significantly lower than the dye-dilution technique, impedance cardiography presently does not determine reliably absolute values of stroke index and is not suitable to evaluate changes of stroke index.