Strategies to slow the progression of renal disease.

Recent multicenter clinical trials have confirmed that it is indeed possible to slow the progression of chronic renal disease in patients with diabetic and nondiabetic nephropathy. Antihypertensive therapy is particularly protective in this regard, either due to the lowering of blood pressure or, as is sometimes the case with ACE inhibition, to mechanisms independent of a systemic hemodynamic effect. Similarly, strict glycemic control has now clearly been shown to ameliorate the progression of diabetic nephropathy, while dietary protein restriction appears to have some benefit, although further studies will be required to establish this definitively.

Hemodynamic theory of progressive renal disease: a 10-year update in brief review.

Experimental studies have suggested that glomerular hypertension is ultimately damaging to the kidney. Prevention of glomerular hypertension by dietary protein restriction or antihypertensive therapy lessens glomerular injury in several experimental models of chronic renal disease. Glomerular hypertension and hyperfiltration also occur in humans with diabetes mellitus, solitary or remnant kidneys, and various forms of acquired renal disease.

Glomerular hypertension: cause and consequence of renal injury.

Background: Glomerular capillary hyperfiltration and hypertension occur in certain disease states and also in response to a reduction in the number of functional nephrons. Experimental studies have shown that these glomerular hemodynamic changes are maladaptive, and ultimately damaging to the kidney. Amelioration of glomerular hyperfunction by dietary protein restriction or antihypertensive therapy lessens glomerular injury in several experimental models of chronic renal disease.

Nitric oxide: a potential mediator of amino acid-induced renal hyperemia and hyperfiltration.

The role of nitric oxide in the modulation of systemic and renal hemodynamics was examined by using N omega-monomethyl-L-arginine (L-NMMA, 110 micrograms/kg/min), a competitive inhibitor of the conversion of L-arginine to nitric oxide. L-NMMA or saline vehicle (9.6 microL/min) was infused intravenously into anesthetized euvolemic Munich-Wistar rats.

Earliest enamel deposits of the rat incisor examined by electron microscopy, electron diffraction, and electron probe microanalysis.

In order to describe initial events in enamel mineralization and to help characterize inorganic-organic interactions in this tissue, the earliest rod and interrod enamel in mandibular incisors from normal young adult (100 gm) rats, perfused with 100% ethylene glycol, has been studied by transmission electron microscopy, selected area electron diffraction, and high-spatial-resolution electron probe microanalysis. Diffraction and probe data were correlated precisely from the same extracellular regions of the tissue. Sites were examined progressively as a function of location a) from the most recently deposited enamel adjacent to ameloblasts toward the dentin-enamel junction and b) from the apical portion of the tooth longitudinally toward its incisal end.

A quantitative microprobe analysis of elements in cortical and nuclear cells of the calf lens.

The outer cortical cells in the calf lens remain transparent under conditions that produce opacity in central nuclear cells. The nuclear cells opacify by a mechanism of cellular restructuring that is associated with a cytoplasmic phase separation while cortical cells do not opacify by this mechanism. In this study the differences in elemental composition of nuclear and cortical cells were analyzed using X-ray emission spectroscopy (XES) of tissue that was prepared for scanning electron microscopy.

Single bovine enamel particles examined by electron optics.

Whole enamel scrapings from teeth of embryonic calves have been separated by density gradient centrifugation in organic solvents into fractions (1.6 less than p less than 2.4 g/cm3) representing progressive stages of mineral phase maturation.

Phase separation and lens cell age.

Using laser light scattering spectroscopy, we are studying age-related changes in the microstructure of lens cytoplasm. We have established in animal models that one of the earliest identifiable stages in cataract development is the presence of a phase transition in the lens cytoplasm. As a result of the phase transition, the cytoplasm separates into microvolumes that differ in their protein concentration.