Nitric oxide inhibition enhances platelet aggregation in experimental anti-Thy-1 nephritis.

In the present paper we studied the role of nitric oxide radicals (NO) on platelet aggregation, fibrinogen deposition, superoxide formation, peroxynitrite formation, hemodynamics, and leukocyte migration in the Thy-1 model of glomerulonephritis. To first study the baseline kinetics of these parameters, groups of anti-Thy-1-treated rats were sacrificed at 1 h, 4 h, 24 h, 3 days, 7 days, and 14 days and compared to controls. Urinary protein excretion was significantly elevated in Thy-1 nephritis at 3 and 7 days. Glomerular macrophages, PMNs, and superoxide anion-positive cells were significantly increased in Thy-1 nephritis. Nitrotyrosine immunoreactivity was absent during the entire study period. Glomerular platelet aggregation was significantly increased in anti-Thy-1 injected rats at 1 h, 4 h, 24 h, and 3 days. Glomerular fibrinogen deposition was significantly elevated at all time points. To elucidate the role of NO in this process, additional groups of anti-Thy-1-injected rats were treated with the NOS inhibitor l-NAME and studied at 24 h. Urinary protein excretion was significantly higher in l-NAME treated Thy-1 rats compared to nontreated Thy-1 rats. Plasma and urine nitrite/nitrate levels were significantly lower in l-NAME-treated Thy-1 rats compared to nontreated Thy-1 rats. Compared to nontreated Thy-1 rats, there were no differences in intraglomerular leukocyte accumulation after treatment with l-NAME. In contrast, we observed a marked increase in platelet aggregation following l-NAME treatment. From these data we conclude that the inflammatory infiltrate in Thy-1 nephritis develops independent of NO radical production, whereas NO radicals prevent the accumulation of platelet aggregates.

Distribution of cytoskeletal proteins, integrins, leukocyte adhesion molecules and extracellular matrix proteins in plastic-embedded human and rat kidneys.

OBJECTIVE: To study the distribution of cytoskeletal proteins (actin, alpha-actinin, vinculin, beta-tubulin, keratin, vimentin, desmin), adhesion molecules for cell-matrix interations (very later antigens [VLA1-61, beta1, beta2 [CD18], vitronectin receptor [alphavbeta3], CD 11b), leukocyte adhesion molecules (ICAM-1) and extracellular matrix proteins (collagen IV, fibronectin, laminin, vitronectin) in human and rat kidneys by using a superior processing and immunohistochemical staining technique. STUDY DESIGN: Human and rat kidneys were fixed in 2% paraformaldehyde, dehydrated in acetone and processed in a new, low-toxic glycol, methacrylate mixture, especially developed for immunohistochemistry. Both the glomeruli and the interstitial areas were carefully examined and scored semiquantitatively. RESULTS: Immunostained plastic sections showed excellent morphology combined with remarkably well preserved antigenicity. CONCLUSION: The above mentioned provides an excellent tool for the accurate localization of a wide variety of antigens at the light microscopic level.

Ovariectomy decreases plasma triglyceride levels and both prevents and alleviates glomerular disease in uninephrectomized female analbuminemic rats.

Female Nagase analbuminemic rats (NAR) are profoundly hypertriglyceridemic and develop proteinuria and glomerulosclerosis when aging and after uninephrectomy (UNX). Ovariectomy (OVX) markedly decreases plasma triglyceride levels in this species. This study evaluated whether decreasing triglyceride levels by OVX could prevent renal disease or alleviate its progression in UNX female NAR. Female NAR underwent OVX at 0, 12, 24, or 36 wk after UNX. In the absence of OVX, the animals developed progressive proteinuria from 18 wk after UNX and showed extensive glomerular sclerosis, lipid deposition, and hypertrophy at euthanasia (49 wk after UNX). These changes were prevented by OVX carried out at 0 or 12 wk, and attenuated by OVX at 24 wk after UNX. If performed at 36 wk after UNX, OVX had no effect on glomerulosclerosis, although it reduced proteinuria. In 95% (20 of 21) of the rats with proteinuria over 10 mg/day, proteinuria decreased in the first 6 wk after OVX. The percentage decrease in proteinuria correlated inversely with the glomerulosclerosis score at euthanasia (r = -0.58, P < 0.01). OVX had no effect on hyperfiltration and hyperperfusion in the UNX rats. OVX consistently reduced plasma triglyceride levels in rats both with and without proteinuria, and it also reduced plasma cholesterol, but only in conjunction with reduction in proteinuria. It was concluded that OVX in UNX female NAR prevents glomerulosclerosis if performed before proteinuria and attenuates further development of established renal disease if performed in a timely manner. This study's data suggest that in UNX female NAR, the lowering of plasma triglyceride levels plays a central role in the renoprotective action of OVX.

High lipid levels in very low density lipoprotein and intermediate density lipoprotein may cause proteinuria and glomerulosclerosis in aging female analbuminemic rats.

BACKGROUND: Male rats are generally more prone to developing renal disease than female rats. However, female Nagase analbuminemic rats (NAR) are profoundly hyperlipidemic and develop proteinuria and glomerulosclerosis after uninephrectomy. Male NAR are less hyperlipidemic and are resistant to developing renal damage after uninephrectomy. Ovariectomy markedly decreases hepatic triglyceride secretion and plasma triglyceride levels in the female NAR. EXPERIMENTAL DESIGN: In this study, we investigated the relationship between plasma lipids and lipoprotein composition as well as the development of proteinuria, glomerular apolipoprotein and lipid deposition, and glomerulosclerosis in aging female and male analbuminemic rats. We also studied whether ovariectomy in female NAR at an early age would protect their renal function in old age. RESULTS: Aging hyperlipidemic female NAR with high triglyceride and cholesterol levels in very low density lipoprotein (VLDL) and intermediate density lipoprotein (IDL) were found to develop spontaneous proteinuria at 9 months of age. Glomerular lipid deposition and glomerulosclerosis were observed at 18 months of age. In male NAR that had lower lipid levels in VLDL and IDL, only mild proteinuria and no glomerular lipid deposition or glomerulosclerosis were observed up to the age of 22 months. Concurrently ovariectomized NAR demonstrated profound and persistent decreases in triglyceride and cholesterol content of VLDL and IDL as well as total plasma triglycerides, without much change in LDL, high density lipoprotein, total plasma cholesterol, or apolipoprotein B, and they remained completely free of proteinuria and glomerulosclerosis. Apolipoprotein B deposition in glomeruli was not different in the oldest female, male, or ovariectomized NAR. No important differences were observed in glomerular diameter between the three different groups up to the age of 1 year. CONCLUSIONS: These findings point to an important role of elevated lipid content of the triglyceride-rich lipoproteins VLDL and IDL in the pathogenesis of proteinuria and glomerulosclerosis in the female NAR.

Interferon-gamma (IFN-gamma) and IL-4 expressed during mercury-induced membranous nephropathy are toxic for cultured podocytes.

The subepithelial immune deposits of Dorus Zadel Black (DZB) rats with mercury-induced membranous nephropathy consist of autoantibodies directed to laminin P1 and of complement. The animals develop massive proteinuria within 10-14 days which is associated with obliteration of foot processes of glomerular visceral epithelial cells (GVEC), or podocytes. Previous studies indicate that these autoantibodies are probably not the sole mediator of proteinuria and GVEC damage. In this study we investigated whether circulating or macrophage-derived cytokines can contribute to the GVEC changes as detected in vivo. In vivo at the height of the proteinuria, increased intraglomerular IFN-gamma immunoreactivity was found. In diseased rats a five-fold increase in intraglomerular macrophages was found, but we could not detect intraglomerular IFN-alpha, IFN-beta, IL-1 beta or tumour necrosis factor-alpha (TNF-alpha) by using immunohistology. Subsequently, we exposed cultured GVEC to these cytokines to investigate their cytotoxic effects on several physiological and structural parameters. IFN-gamma and IL-4 were the only cytokines that exerted toxic effects, resulting in a rapidly decreased transepithelial resistance of confluent monolayers, which was closely associated with altered immunoreactivity of the tight junction protein ZO-1. IL-4 also affected vimentin and laminin immunoreactivity. IFN-gamma and IL-4 only interfered with monolayer integrity when added to the basolateral side of the GVEC, indicating specific (receptor-mediated) effects. Only IL-4 decreased the viability of the cells, and treated monolayers demonstrated an increased passage of the 44-kD protein horseradish peroxidase. From our experiments we concluded that IFN-gamma subtly affected monolayer integrity at the level of the tight junctions, and that IL-4 additionally induced cell death. We hypothesize that the toxic effects of the cytokines IFN-gamma and IL-4 as seen with cultured podocytes are necessary together with the autoantibodies, for the ultimate induction of proteinuria in mercury nephropathy in the DZB rat.

Puromycin aminonucleoside and adriamycin disturb cytoskeletal and extracellular matrix protein organization, but not protein synthesis of cultured glomerular epithelial cells.

Puromycin aminonucleoside (PA) and Adriamycin (ADR) cause glomerular proteinuria associated with degenerative alterations of glomerular visceral epithelial cells (GVEC) and detachment from the glomerular basement membrane when administered to rats. This in vitro study was performed to define, in detail, the quantitative and qualitative changes of a number of adhesion-associated proteins (cytoskeletal, extracellular matrix and integrin proteins) upon exposure to PA and ADR. By immunofluorescence we observed: (1) dose- and incubation-time-dependent filament pattern changes and decreased staining of the cytoskeletal proteins actin, vimentin, keratin, and beta-tubulin; (2) an altered distribution, and decreased expression of the extracellular matrix proteins laminin and heparan sulfate and (3) a loss of the beta 1-integrin focal adhesions upon exposure to PA and ADR. Using an ELISA, a concentration-dependent decrease was found (a 50% reduction with 50 micrograms/ml PA for 48 h and with 2 micrograms/ml ADR for 24 h) in the production of cytoskeletal and extracellular matrix proteins per cell. These general effects were suggestive of a disturbance of protein synthesis but, by metabolic labelling studies, no reduction in overall protein synthesis was found. Using two-dimensional PAGE on 35S-methionine steady-state labeled cells, no changes were found in intracellular protein patterns of PA- and ADR-treated cells (pH 5-7.5, MW 110-20 kD). We hypothesize that exposure of GVEC in vitro to PA and ADR might result, directly or indirectly, in perturbation of the macromolecular organization of cytoskeletal and extracellular matrix proteins with loss of GVEC adhesion.

The constipation quandary.

Constipation. It's uncomfortable, worrisome and, unhappily, a common problem in the elderly. In the largest study to date, for instance, 21 to 34 per cent of American women over 65 years reported experiencing it, as did nine to 20 per cent of the men. Elders are particularly at risk of becoming constipated because of age-related changes like weakening of the intestinal muscles, decreased peristalsis and altered activity. This risk is magnified in individuals with hypotonic colon function or central nervous system lesions, and in those who are immobilized and debilitated.

General medicine expanded role nurse: role description.

In an effort to cope with the changing health care environment, University Hospital, London, Canada provided the opportunity for two nurses to develop expanded nursing roles in general internal medicine. Direct care functions centre on the expert practitioner role. Whereas, indirect care functions include educator, consultant/resource person and researcher. Although the expanded roles are in the beginning stages of development, these nurses have articulated their activities and responsibilities as expanded role nurses in the medicine service.

Renal apolipoproteins in nephrotic rats.

Recent experimental data suggest a role for lipids in the pathogenesis of glomerulosclerosis. In this study, we examined the main apolipoproteins (apo) of high density lipoproteins (A-I, A-IV, E), low density lipoproteins (B), and very low density lipoproteins (B,E) in plasma and kidney tissue of rats with puromycin aminonucleoside or adriamycin nephrosis. In full-blown nephrosis, plasma concentrations of apo A-I and apo B were significantly elevated, apo A-IV and apo E levels did not change. Immunohistological studies in plastic sections revealed increased apo A-I, apo A-IV, and apo E immunoreactivity in glomerular visceral epithelial cells both in puromycin aminonucleoside and adriamycin nephrosis. This was confirmed by immunoelectronmicroscopy. In addition, apo B and apo E were encountered in increased amounts in the mesangium and colocalized with Oil Red O-positive lipid deposits, particularly in puromycin aminonucleoside nephrosis rats. Double-staining showed a preferential localization of apo B and apo E at sites of increased mesangial matrix in close proximity to ED1-positive foam cells, i.e., the mesangial macrophages. The close topographic association between apo B and apo E, lipid deposits, and macrophages in the mesangium lend further support to the concept of lipid-mediated glomerular injury in nephrosis.

Canada's health care system provides lessons for NPs.

With increasing economic pressures, swaying public opinion and new government policies rationing health care resources, nurses in Canada are again challenging physicians for room to practice as nurse practitioners. Although the last Canadian nurse practitioner program was discontinued in 1983, and it was argued that the death of the role was inevitable in Canada's health care system, nurse practitioners have not vanished. Social plans in the United States are drawing heavily on the Canadian model of universal access and a government-funded health care system, and dramatic changes are taking place in Ontario's health care system. Now more than ever it is important that nurse practitioners understand Canada's health care system, why the NP role in Ontario has not been highly successful, and why the time is right for reintroduction of nurse practitioners into Ontario's health care system.

Glomerular macrophage modulation affects mesangial expansion in the rat after renal ablation.

Recent studies have provided evidence for the involvement of macrophages (m phi) in various types of human and experimental glomerular disease. The aim of the present study was to examine the effect of m phi depletion on glomerular injury after 3/4 renal ablation in the rat. This "remnant kidney" model is a widely used experimental model of focal and segmental glomerulosclerosis. Sustained glomerular m phi depletion was induced in remnant kidney rats by a regimen of sublethal triple systemic X-irradiation with shielding of the kidney remnants. Groups of 8 X-irradiated and 8 non-irradiated rats were studied at 5, 9, and 13 weeks after renal ablation. X-irradiated rats showed severe peripheral blood leukopenia at 5 and 9 weeks which had normalized at 13 weeks. The number of remnant glomerular m phi (immunohistochemistry with the monoclonal antibody ED1) in X-irradiated rats at 5 weeks was significantly lower when compared to non-irradiated remnant kidney rats. A rebound effect occurred at 9 and 13 weeks with increased m phi in remnant glomeruli of X-irradiated rats. Light microscopic examination disclosed significantly lower semiquantitative scores for mesangial cellularity and mesangial matrix expansion in remnant glomeruli of X-irradiated rats at 5 weeks when compared to non-irradiated remnant kidney rats. Mesangial matrix expansion had increased in X-irradiated rats at 9 and 13 weeks after ablation coincident with elevated glomerular m phi at these intervals. Multiple linear regression analysis indicated a highly significant contribution of m phi to the best fitting regression model predicting mesangial matrix expansion (multiple r2 = 0.81). In conclusion, these data provide evidence for a contributory role of m phi in the evolution of glomerular injury in the rat after renal ablation.