Sheldon Glabman

Renal functional reserve in humans: Effect of protein intake on glomerular filtration rate

This study was designed to investigate the effect of protein intake on glomerular filtration rate, and to demonstrate and evaluate the functional reserve of the kidney. Normal subjects ingesting a protein diet had a significantly higher creatinine clearance than a comparable group of normal subjects ingesting a vegetarian diet. A progressive increment in protein intake in normal volunteers resulted in a significant increase in creatinine clearance. Diurnal variations in creatinine clearance were found. These daily variations correlated well with the periods of food intake. The capacity of the kidney to increase its level of function with protein intake suggests a renal function reserve. In short-term studies, the effect of a protein load on glomerular filtration rate was evaluated. Normal subjects showed an increase in glomerular filtration rate two and a half hours after protein load to a maximal glomerular filtration rate of 171.0 +/- 7.7 ml per minute. In patients with a reduced number of nephrons, renal functional reserve may be diminished or absent.

Continuous Arteriovenous Hemofiltration in the Critically Ill Patient: Clinical Use and Operational Characteristics

Continuous arteriovenous hemofiltration is an extracorporeal technique for the treatment of fluid overload and electrolyte disturbances and for the removal of urea nitrogen. This technique is especially applicable in critically ill patients with hemodynamic instability. A special filter and modified hemodialysis blood lines can easily and rapidly be attached to a patient. No special blood access is needed. Fluids and solutes are removed from the patient by ultrafiltration. A net filtration pressure inside the filter causes an ultrafiltrate to form. The extracorporeal circuit can be kept in place for hours or days.

Short-term protein loading in assessment of patients with renal disease☆

The effect of short-term protein loading on the glomerular filtration rate in normal persons and patients with renal disease was evaluated. Previous studies have demonstrated that in healthy subjects, protein loading results in an increased glomerular filtration rate. By determining the glomerular filtration rate preceding (baseline glomerular filtration rate) and following (test glomerular filtration rate) oral protein loading, it was possible to define (1) the filtration capacity (test glomerular filtration rate) and (2) the renal reserve (test glomerular filtration rate - baseline glomerular filtration rate) of the kidney. In normal persons, filtration capacity averaged 157 +/- 13 ml per minute and renal reserve 34 ml per minute. The test glomerular filtration rate was reproducible and independent of protein intake, whereas baseline glomerular filtration rate was significantly influenced by diet. Patients with renal disease were found to have a reduced renal reserve and/or a diminished filtration capacity. The reduction in filtration capacity appears to correlate with the damage sustained by the organ. It is suggested that an abnormal response to protein loading in renal disease may herald the fall in the baseline glomerular filtration rate and the rise in plasma creatinine level.

Renal hemodynamic changes in humans: Response to protein loading in normal and diseased kidneys

This study was undertaken to define the renal hemodynamic changes that mediate the acute response to an oral protein load. Three groups of subjects were studied: (1) disease-free subjects; (2) patients with chronic renal disease of various causes, except for diabetes mellitus, documented by history and/or renal biopsy; and (3) patients with diabetes mellitus, that is, a history of hyperglycemia requiring antihyperglycemic therapy. All subjects were studied before (baseline) and after (test) ingestion of a protein load. Glomerular filtration rate and effective renal plasma flow were evaluated by inulin and para-amino-hippurate, respectively. In the disease-free subjects, the mean baseline glomerular filtration rate and renal plasma flow were 122 +/- 10 ml/minute/1.73 m2 and 644 +/- 64 ml/minute/1.73 m2, whereas test glomerular filtration rate and renal plasma flow were 151 +/- 15 ml/minute/1.73 m2 and 791 +/- 111 ml/minute/1.73 m2, respectively. In patients with chronic renal disease, the test glomerular filtration rate and renal plasma flow were related to the severity of the disease. The more severe the disease, the lower the absolute test values and the smaller the increment from baseline to test values. Patients with diabetes mellitus had a paradoxic response to ingestion of a protein load. Glomerular filtration rate fell while renal plasma flow remained unchanged. This response was observed in all diabetic patients regardless of the type of diabetes or whether clinical evidence of diabetic nephropathy was absent, minimal, or severe.

Sodium Fluxes during Hemodialysis

Three sets of experiments were performed to determine the effect of the dialysate sodium concentration on the sodium balance of patients undergoing maintenance hemodialysis. First, patients were treat

PERSISTENT IMMUNOGLOBULINURIA IN IRREVERSIBLE RENAL ALLOGRAFT REJECTION IN HUMANS

SUMMARY To evaluate the extent of injury in short- and long-term renal allografts, the urinary excretion of IgG, IgA, and IgM was observed during acute rejection crisis. In reversible rejection, treatment resulted in prompt correction of immunoglobulinuria, whereas in irreversible crisis urinary immunoglobulin levels continuously increased in spite of the same antirejection treatment. A good prognosis in long-term allografts was shown by low levels of immunoglobulinuria; unstable graft function had higher levels. Immunoglobulinuria can be used as an additional test to evaluate the reversibility of acute rejection, and also has significance in the long-term situation.

Filtration Peritoneal Dialysis

By connecting an Amicon Hemofilter 20 to a Tenckhoff catheter protein loss during peritoneal dialysis was eliminated. All proteins leaving the abdomen in the dialysate fluid were trapped in the filter and returned to the patients abdomen with the next infusion of dialysate. 4 patients were studied during standard and filtration peritoneal dialysis. In standard peritoneal dialysis the total protein loss was approximately 17.0 g. Filtration peritoneal dialysis appeared to alter the transfer of protein from the peritoneal membrane and/or capillary wall to the dialysate fluid.