The data support the hypothesis that the number of nephrons is reduced in white patients with primary hypertension.

Using stereological techniques capillaries, interstitium and myocardial fibers were analyzed in perfusion-fixed hearts of subtotally nephrectomized male Sprague-Dawley rats with uremia of 14 months duration (or their sham-operated controls). Uremic rats had higher systolic blood pressure (140 +/- 20.3 mm Hg vs. 119 +/- 6.61 mm Hg) and left ventricular weight/body weight ratio (3.37 +/- 0.09 mg/kg vs. 2.01 +/- 0.12 mg/kg) than controls, and had slight anemia (Hct 35.0 +/- 3.16% vs. 40.4 +/- 3.3%). Length density (Lv) of capillaries, that is, capillary length per unit myocardial volume, was significantly (P < 0.001) decreased in uremia (2485 +/- 264 mm/mm3 vs. 3329 +/- 194 mm/mm3) versus controls. In parallel, surface density and volume density of the capillary lumina were also reduced (7.95 +/- 1.69 cm3/cm3 vs. 11.4 +/- 1.8 cm3/cm3) in the uremic rats. We conclude that in experimental uremia, cardiac hypertrophy is not accompanied by a commensurate increase in capillaries.

We report that the spirochete B. burgdorferi induces progressive polyarthritis and carditis in mice with severe combined immunodeficiency syndrome (scid) but not in normal C.B-17 mice. The onset and severity of the disease were dependent on (a) the viability; (b) the infectivity; and (c) the dose of inoculated B. burgdorferi organisms. Infective spirochetes were isolated from both blood and joints of inoculated scid mice. These findings suggest that B. burgdorferi-induced chronic arthritis and carditis in mice develops independently of lymphocyte function and makes the scid mouse an attractive laboratory model to study the role of the immune system in experimental Lyme Borreliosis.

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