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This study was planned to investigate the effect of ischemic dysfunction of the free wall of the right ventricle on right and left ventricular performance in the presence of a normally contracting interventricular septum. The experiments were performed in 6 anesthetized dogs in which echocardiogram, electrocardiogram, aortic blood pressure and left and right ventricular pressure were recorded. In the dog, the contractility of the septum is not affected by the occlusion of the right coronary artery which does not perfuse this part of the myocardium. Complete occlusion of the major individual ventricular branches and partial occlusion of the main right coronary artery did not impair right ventricular performance. Only complete occlusion of the main artery affected right and left ventricular function as revealed by echocardiogram. Reduced output by the ischemic right ventricle caused a reduction in left ventricular diastolic and systolic dimensions and in left ventricular developed pressure without any effect on left ventricular end-diastolic pressure.

We have studied the role of interleukin-2 (IL-2) and its receptors in the impaired in vitro lymphocyte response characteristic of hemodialysis patients treated by means of cuprophane membranes. The proliferative response of T lymphocytes as well as T-cell-dependent B cell proliferation after stimulation with mitogens was significantly reduced in hemodialysis patients. The in vitro production of IL-2 after such stimulation in parallel cultures was found to be similar in patients and in controls. The expression of IL-2 receptor on the lymphocyte cellular membrane in the hemodialysis group was also similar to controls. The in vitro proliferative response of uremic lymphocytes to exogenous IL-2, however, was significantly depressed suggesting a reduced availability of biologically active IL-2 receptor. The release of soluble IL-2 receptor by lectin-stimulated lymphocytes in culture was also significantly lower in the patient group; yet, hemodialysis patients has a strikingly elevated level of plasma soluble IL-2 receptor, and similar high levels were also found in three other groups of end-stage renal disease patients dialyzed by means of cellulose acetate, polysulfone and polyacrylonitrile membranes, as well as in a group of uremic patients on conservative treatment. In the hemodialysis patient group a significant positive correlation between levels of soluble IL-2 receptor and the duration of hemodialysis was found. Since soluble IL-2 receptor has been reported to down-regulate lymphocyte responses, the elevation in plasma levels of soluble IL-2 receptor in hemodialysis patients may be a pathogenetic factor in the progressive development of impaired immunity associated with end-stage renal disease.

The role of hemodialysis (HD) as an arrhythmogenic event has recently been emphasized. We studied 18 patients by Holter monitoring, comparing the arrhythmogenic effect of acetate dialysis (AHD) and bicarbonate dialysis (BHD). The frequency of ventricular arrhythmias was 93 +/- 66/h in AHD and 32 +/- 26/h in BHD (p less than 0.005). According to the classification of Lown and Graboys, classes III and IV were more often to be found in AHD than in BHD and no patient on BHD was in class IVB and class V. Five patients affected with ischemic heart disease had more frequent and dangerous ventricular arrhythmias than the others; a significant difference between buffers was recorded in all cases but 1. Intradialytic changes in body weight, hematocrit, osmolarity, ionized calcium and potassium during AHD and BHD were similar. The two methods only differed in the quickness and degree of correction of acidosis, and this was related to a significant difference in intraerythrocytic potassium at the end of the session. The quicker and more regular correction of acidosis with BHD and the consequent difference in ionic flows between the intra- and extracellular spaces, as demonstrated by changes in intraerythrocytic potassium at the end of the session, could account for the seemingly less arrhythmogenic effect of BHD.

Fabry's disease, a very unusual cause of end-stage renal disease, is actually included in the contraindications to renal transplantation. The few published studies, based on very few patients, report a high rate of life-threatening complications, mostly infectious, following kidney transplant in these patients. We have evaluated retrospectively 12 uremic patients in renal function replacement treatment for Fabry's disease. In transplanted patients (n = 8; whole observation period 241 months), no lethal complication was ever recorded. Fever and acroparesthesias ameliorated. Cardio- and cerebrovascular complications did not progress. Although no increase in serum enzymatic activity was measured, renal transplantation provided an alternative route by excretion of an amount of the metabolic product (ceramide-trihexoside). When undergoing maintenance hemodialysis (whole observation period 291 months), 3 deaths and several cardiac and cerebral complications occurred. Angiokeratomas, fever and pains were unmodified. These data disagree with what has been previously stated. The transplanted patients' survival shifts towards the all-time rate and a satisfying rehabilitation is provided. Fabry's disease should not be considered a high-risk disease; and patients suffering from it should decidedly enter a regular transplantation program.

Uremic patients are at high risk of hepatitis B virus (HBV) infection and, despite the availability and efficacy of hepatitis B vaccine, a high rate of non responders has been reported. Forty uremic patients undergoing maintenance hemodialysis who failed to produce any measurable anti-HBs antibody response after 4 administrations of 5 micrograms of Hevac B Pasteur vaccine were admitted to a randomized controlled clinical trial. Group A (14 patients) received 3 doses of 5 micrograms s.c. each of vaccine at monthly intervals and 12 doses of 50 mg s.c. of thymopentin on alternate days between the first and the second vaccination. Group B (11 patients) received 3 doses of 5 micrograms s.c. each of vaccine at monthly intervals. Group C (15 patients) received 3 doses of 10 micrograms s.c. each of vaccine at monthly intervals. Immunization rates were 86% in group A (on both 1-month and 6-month checks), 36% on the 1-month and 27% on the 6-month check in group B, 53% on the 1-month and 47% on the 6-month check in group C. Anti-HBs antibody titers were similar in group A and C but notably lower in group B. Thymopentin seems as useful therapeutical tool for non responder patients. As it promotes T cell maturation and responsiveness, which are impaired in uremia, it could play a major part in the management of uremic immunodeficiency.

The pattern of circulating calcitonin (CT) has been studied in relation to other humoral factors (PTH, calcium, phosphate and magnesium) in patients with chronic renal failure on either conservative or dialysis treatment. The latter group was studied before and after dialysis. In both groups, in basal conditions there was a significant increase in the circulating levels of CT, PTH, phosphate and magnesium and a significant decrease in calcemia compared to control group values. Positive correlations were found between increased CT and PTH and between CT and phosphate in uremic patients on conservative medical treatment, but not in those on hemodialysis. In the hemodialyzed group, the postdialysis increase in calcemia was significantly correlated to an increase in calcitoninemia. These data would indicate that even in severe uremia parafollicular cells are still able to increase CT secretion in response to physiological stimuli.