Herbert Lubowitz

Pulse Methylprednisolone Therapy in Idiopathic, Rapidly Progressive Glomerulonephritis

Idiopathic crescentic glomerulonephritis is associated with a 70% to 80% incidence of end-stage renal failure. Oral corticosteroid therapy in combination with immunosuppressive agents or anticoagulants has not altered the prognosis of this disease. We have seen five adults with idiopathic crescentic glomerulonephritis and treated them with intravenous methylprednisolone. Before therapy, the average serum creatinine concentration was 7.4 +/- 1.3 mg/dL (chi-square +/- SEM). This value declined to 2.0 +/- 0.48 mg/dL within 4 weeks. All patients continue to maintain stable renal function over an average follow-up period of 19 months (range 1.5 to 36 months). These data suggest that a prospective controlled trial of this therapy is warranted in the management of this entity.

Glucose Titration Studies in Patients with Chronic Progressive Renal Disease

Glucose titration studies were performed on 17 patients with either chronic pyelonephritis or chronic glomerulonephritis. Glomerular filtration rates for the group ranged from 4.3 to 58.1 ml per minute. In none of the patients in whom the glomerular filtration rate was over 15 ml per minute was there appreciable splay, and the mean titration curve for these patients resembled that obtained by Smith and associates in normal man (1). In half of this group of eight patients, GFR ranged from 16.6 to 22.7 ml per minute; in the other half values ranged from 42.3 to 58.1 ml per minute. Yet, the mean titration curves were identical for the two groups. In addition, no difference was observed in the titration curves for patients with pyelonephritis and those with glomerulonephritis. In patients with GFR values below 15 ml per minute, increased splay was observed, and below a GFR of 10 ml per minute, the splay was very marked. Both the absence of exaggerated splay in patients with reduction of glomerular filtration rate by as much as 85%, and the emergence of exaggerated splay in patients with more marked reduction of GFR, require explanation. Theoretical considerations are presented in the text.

Investigation of Single Nephrons in the Chronically Diseased (Pyelonephritic) Kidney of the Rat Using Micropuncture Techniques

Unilateral pyelonephritis was induced in the rat and micropunture techniques were used to assess nephron function in individual nephrons from chronically diseased and normal kidneys in the same animal

The Pathophysiology of Renal Insufficiency: On the Functional Transformations in the Residual Nephrons with Advancing Disease

By viewing the kidney in chronic progressive renal disease as an organized responsive organ which suffers from progressive reduction in functioning nephrons, but in which the surviving nephrons often respond appropriately to the biologic needs of the host, a prospective approach may be taken to the interpretation of the abnormalities of renal insufficiency, and clinical management may be planned with increasing insight, physiologic rationale, and intellectual satisfaction.

Exchange diffusion in human red blood cells.

Summary Characteristics of a model for the study of diffusional movement in human red blood cells have been examined. Tracer influx of sodium was accelerated in red cells with high internal sodium content. This occurred both in fresh and stored human red blood cells. These results were not due to an alteration in electrical potential across the red blood cell membrane and uptake of a non-polar tracer was not enhanced by high internal sodium content. The data seem best explained by an exchange diffusion process. I am grateful to Professor R. Whittam for suggesting the model and to both Professor Whittam and Dr. Neal S. Bricker for reviewing this manuscript. Mr. Foster Harris provided valuable technical assistance. This work was supported by U.S. Public Health Service Grant No. AM 14586-01.

Glucose reabsorption in experimental glomerulonephritis.

Summary The relationship between glo-merular filtration rate and tubular glucose reabsorption was examined in rats with experimental glomerulonephritis. Glomerular filtration rates (single kidney) varied from 0.09 to 0.95 ml/min and superficial nephron filtration rates ranged from 4.4 to 38.2 nl/ min. A direct linear relationship between filtration rate and maximal glucose reabsorption rates was observed in individual superficial nephrons as well as in the whole kidney. Changes in peritubular oncotic pressure and extracellular fluid volume modified glucose reabsorptive rates, but the linear relationship between filtration rate and glucose reabsorption persisted. These data support the thesis that glomerulo-tubular balance for glucose is a characteristic feature of renal glucose transport. The studies referred to in this manuscript were supported by Public Health Service Grant No. T501 HL06008. We are also grateful to Dr. Oliver H. Lowry and Ms. Margaret Philips for performing the microenzymatic glucose determinations.