Daniel A. Terreros

Elements of a Paracrine Tubular Renin-Angiotensin System Along the Entire Nephron

The renin-angiotensin system is a major regulator of body sodium, predominantly through the actions of intrarenal angiotensin II of unclear origin. We show that polarized epithelium of the proximal tubule synthesizes and secretes angiotensinogen at its apical side and that the protein can be detected in urine as a function of dietary sodium. Furthermore, we demonstrate that renin is expressed and secreted in a restricted nephron segment, the connecting tubule, also in a sodium-dependent fashion. A paracrine renin-angiotensin system operating along the entire nephron may contribute to long-term arterial pressure regulation by integrating distant tubular sodium-reabsorbing functions.

Effects of Dietary Sodium and Genetic Background on Angiotensinogen and Renin in Mouse

Elements of a renin-angiotensin system expressed along the entire nephron, including angiotensinogen secreted by proximal tubule and renin expressed in connecting tubule, may participate in the regulation of sodium reabsorption at multiple sites of the nephron. The response of this tubular renin-angiotensin system to stepwise changes in dietary sodium was investigated in 2 mouse strains, the sodium-sensitive inbred C57BL/6 and the sodium-resistant CD1 outbred. Plasma angiotensinogen was not affected by sodium regimen, whereas plasma renin increased 2-fold under low sodium. In both strains, the variation in urinary parameters did not parallel the changes observed in plasma. Angiotensinogen and renin excretion were significantly higher under high sodium than under low sodium. Water deprivation, by contrast, induced significant activation in the tubular expression of angiotensinogen and renin. C57BL/6 exhibited significantly higher urinary excretion of angiotensinogen than did CD1 animals under both conditions of sodium intake. The extent to which these urinary parameters reflect systemic or tubular responses to challenges of sodium homeostasis may depend on the relative contribution of sodium restriction and volume depletion.

A controlled study of the argon beam coagulator for partial nephrectomy.

An argon beam coagulator was evaluated in 25 canine partial nephrectomies to determine its hemostatic capabilities, safety and degree of thermal injury to renal parenchyma. Comparison was made with a control group of seven partial nephrectomies performed by standard technique. In both groups the procedure was performed without renal cooling or clamping of the renal artery. The argon beam coagulator was operated with a power output of 130 watts. Mean operative time for partial nephrectomy was 22 minutes in the control group versus 10 minutes when the argon coagulator was used (p less than 0.001). Mean blood loss was 276 cc by standard technique but only 135 cc with the argon coagulator (p less than 0.001). A regular eschar with a mean depth of tissue necrosis of 2.4 mm. was observed with the argon coagulator.

A screening study of prostate cancer in high risk families.

In a study of the familial risk of prostate cancer 17 sets of 2 brothers with prostate cancer were identified. A total of 34 first-degree relatives of these probands (sons and brothers, 55 to 80 years old) underwent an intensive screening examination that included prostate specific antigen, digital rectal examination, transrectal ultrasound and systematic as well as clinically directed core needle biopsies. Previously unsuspected and clinically relevant cancers were found in 8 men (24%), compared to the approximately 1 expected (p less than 0.01). Of these cancers 2 were detected by the systematic biopsies. This study emphasizes the importance of thorough screening in first-degree relatives of prostate cancer patients.

Percutaneous Native Renal Biopsy: Comparison of a 1.2-mm Spring-driven System With a Traditional 2-mm Hand-driven System

Over the last few years spring-driven mechanical biopsy guns have been introduced for performing renal biopsies. There has been little research done comparing these guns with traditional hand-driven needles in performing biopsies of native kidneys. We wished to compare our experience with the two needle types. We studied retrospectively the results and complication rates of 155 native kidney biopsies. Sixty-nine were performed with hand-driven 14-gauge needles and eighty-six with 18-gauge, spring-driven biopsy guns. Sufficient tissue for diagnosis was obtained in 96% of cases in the hand-driven group compared with 99% in the biopsy gun group (P = NS). Complications occurred in six cases in the hand-driven group compared with one case in the biopsy gun group (P = 0.02). As expected, the reported number of glomeruli per core in the 14-gauge cores was greater than in the 18-gauge cores (16.5 v 6.2, P < 0.01). This was partially offset by the greater number of passes made with the smaller needle. We conclude that similar results can be expected from both biopsy methods, with a possible slight decrease in complications using biopsy guns with smaller needle diameters.

Immune Complex Glomerulonephritis With Unusual Microfibrillar Deposits Associated With Primary Bone Marrow Lymphoma

Glomerular microfibrillary deposits are characteristic of several diseases of the kidney. In a number of glomerulopathies, the nature of these microfibrillary deposits is critical in classifying the renal lesion and in suggesting the possibility of an associated systemic process. However, it is likely that as efforts are made to classify glomerulopathies with microfibrillary deposits, certain cases will defy categorization. We describe one such case in which a patient presented with rapidly progressive glomerulonephritis associated with large subepithelial, parallel-arrayed microfibrillar deposits associated with a primary bone marrow B-cell lymphoma. While IgG, C3, and lambda and kappa light chains were deposited in the glomerulus, serum and urine protein electrophoresis were normal. Treatment with Cytoxan and prednisone caused simultaneous remission of the lymphoma and the glomerulonephritis. Relapse of the lymphoma was associated with rapid deterioration of renal function. This case may represent a newly described variant of immune complex-mediated glomerulonephritis associated with microfibrillary deposits. The possibility is raised that the glomerular lesion is due to atypical immunoglobulins synthesized by a bone marrow lymphoma.