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Biomedical subjects

L G Feld

Publications and source records attributed to L G Feld.

At least 91 records · Page 5Linked to original sources
PubMed1981

Renal lesions and proteinuria in the spontaneously hypertensive rat made normotensive by treatment.

Spontaneously hypertensive rats (SHR) (N = 40) were maintained at normal blood pressure to the age of 100 weeks by treatment (reserpine, hydralazine, and chlorothiazide) beginning at intervals in groups of eight, from the 5th to 45th week. Mortality rates, patterns of proteinuria, and glomerular and arteriolar pathology were compared with that of treated and untreated normotensive Wistar-Kyoto (WKY) controls matched for age (N = 39) and untreated SHR's (N = 26). Treatment clearly prolongs life in SHR's, the mortality rate for untreated being 100% at 75 weeks versus no deaths at that age among 24 SHR's treated before 20th week. At 100 weeks, treated SHR's were excreting eight times the baseline values of urinary protein, whereas WKY's had hardly increased from baseline values. At 100 weeks, normotensive SHR's showed fibrinoid necrosis, sclerosis, and pericapsular fibrosis of glomeruli, whereas no morphologic damage was found in glomeruli or renal arterioles of WKY. Glomerular lesions in normotensive SHR's are indistinguishable in kind from their hypertensive counterparts, but occur somewhat later. Juxtamedullary glomeruli initially suffer the greatest damage and appear to be the major source of urinary protein. These findings speak against the hypothesis of an increased intravascular pressure as the major factor in the pathogenesis of arteriolar sclerosis and rather favor a genetic defect in the vascular system of the SHR, a defect strongly associated with the hypertensive trait. A possible relationship of this defect to inherited membrane abnormalities recently described in RBC and smooth muscle cells of SHR is discussed.

Age Factors↗
PubMed1981

Renal injury and proteinuria in female spontaneously hypertensive rats.

This investigation describes the evolution of functional and morphological changes in the kidney of female spontaneously hypertensive rats (SHR; 5-90 weeks) and control animals of the same genetic strain, Wistar-Kyoto (WKY). Systolic blood pressure in SHR was 162.0 +/- (SD) 14.1 mm Hg up to 45 weeks, then increased to 189.4 +/- (SD) 16.6 mm Hg (50-90 weeks). Blood pressure in WKY controls remained constant (117.8 +/- 13.6 mm Hg, 5-100 weeks). Protein excretion in the SHR was higher than controls (1.5 +/- 0.5 mg/24 h x 100 g BW, 5-100 weeks) from week 30 on. At 90 weeks, excretion rose to 26.1 +/- 9.8 mg/24 h x 100 g BW and is predominately an albuminuria. After 70 weeks superficial tubular fluid albumin concentration in the SHR is significantly increased (p less than 0.001) over controls. Microscopic changes were evident in glomeruli, tubules, interstitium and arterial vessels at 72-90 weeks and demonstrated an increasing gradient of severity from outer to inner cortex. Glomeruli show sclerosis, fibrinoid necrosis and pericapsular fibrosis. Glomeruli studied with a polyanionic stain revealed a marked decrease in staining affinity of deep, compared to superficial glomeruli. The arterial lesions consisted of thickening of the intima and hyperplasia of the media. WKY kidneys were unremarkable. The selectivity of renal injury and proteinuria in the female SHR is similar to that in the male SHR. However, the evolution of these changes is delayed and may be related to a lower blood pressure until 50 weeks of age.

Age Factors↗
PubMed1979

Zona reticularis in aging spontaneously hypertensive rats: a quantitative ultrastructural study of 70- and 95-week-old animals.

The zona reticularis of 70- and 95-week-old female Wistar-Kyoto (WKY) and spontaneously hypertensive (SH) rats was studied by quantitative stereologic techniques. The zona reticularis in the adrenal gland of 70-week-old SH rats was virtually identical to that of 70-week-old WKY rats. In both SH and WKY rats at 95 weeks of age, however, there was hypertrophy of smooth endoplasmic reticulum reflected quantitatively in increased volume and surface area, as compared with that of WKY rats or SH rats at 70 weeks of age. Ninety-five-week-old WKY rats had a significantly greater mitochondrial volume/cell and surface area of mitochondrial membranes than SH rats. Inclusion of lipid droplets within mitochondria was seen in zona reticularis cells from SH and WKY rats at 70 weeks of age; mitochondria-lipid-droplet association was more frequent at 95 weeks of age. The volume of lipofuscin per cell was significantly greater in WKY than in SH rats at 95 weeks of age. Thus, by quantitative techniques, one can see that the zona reticularis of 95-week-old SH rats differs from that of WKY rats, principally in the presence of smaller cells with a smaller surface area of mitochondrial cristae and a reduced volume of mitochondria, lipofuscin, and lipid droplets.

Adrenal Cortex↗