ISSN:0250-8095    

DOI:10.1159/000168047

出版商:S. Karger AG    

年代:1990

数据来源: Karger

ISSN:0250-8095    

DOI:10.1159/000168185

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

Glomerular capillaries are perfused at a high hydraulic pressure. Since the capillary mesangium interface presents no morphologically apparent pressure barrier, it is suggested that the hydraulic pressure in the mesangium may also be high. This paper analyzes the structures in the glomerular tuft that are capable of counteracting the distending forces exerted on the tuft by the high hydraulic pressure in its center. The skeletal element of the glomerular tuft is the glomerular basement membrane (GBM). The combination of the GBM with the contractile apparatus of mesangial cells represents the main system stabilizing the glomerular tuft. The mesangial cell-GBM connections counteracting the expansion of glomerular capillaries appear less susceptible to injury than those counteracting mesangial expansion.

ISSN:0250-8095    

DOI:10.1159/000168186

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

Evidence from human case reports, epidemiologic studies and animal experiments have suggested that exposure to organic solvents is associated with a wide spectrum of renal disorders, including tubular necrosis, interstitial disease, glomerulonephritis and neoplasia. This review summarizes what is known about solvent-induced renal damage in humans and experimental animals, with emphasis on hypothesized mechanisms by which this broad range of disorders may occur.

ISSN:0250-8095    

DOI:10.1159/000168048

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

The glomerular polyanion comprises all anionic sites of glomerular cell surfaces, basement membranes and extracellular matrix. Charged structures may play a critical pathophysiologic role within the glomerular microcirculation, as loss of charges results in altered permselectivity of the filtration barrier and proteinuria. Neutralization of cell surface negative charges of cultured glomerular epithelial and mesangial cells by the polycation poly-L-lysine (PL) is accompanied by increased prostanoid synthesis. Recent studies have shown that PL enhances mesangial cell proliferation in culture. Conversely, the polyanion heparin prevents the effect of PL, and inhibits the growth-stimulatory effect of serum. Thus, our data suggest that the glomerular polyanion, in addition to maintaining the integrity of the filtration barrier, regulates key cell functions such as eicosanoid biosynthesis and proliferation.

ISSN:0250-8095    

DOI:10.1159/000168188

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

Uncharged dextrans of graded size (28–60 Å) were used to evaluate glomerular barrier size selectivity in 13 nephrotic patients with diffuse proliferative lupus nephritis. Transglomerular sieving was enhanced selectively for dextrans of > 46 Å radius when the nephritis was active and restored towards normal by immunosuppressive therapy. A mathematical model of hindered solute transport through a porous membrane revealed these findings to reflect the prevalence in the glomerular barrier of a subset of enlarged, nondiscriminatory pores. Although few in number, such enlarged pores accounted for both the magnitude and composition of observed proteinuria. We infer that impaired barrier size selectivity underlies the proteinuria that attends lupus nephritis, and that impairment of barrier charge selectivity need not be invoked in this circumsta

ISSN:0250-8095    

DOI:10.1159/000168189

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

Twelve cases of glomerulonephritis in patients without systemic diseases, displaying organized glomerular deposits, were reported. Microfibrils (ll-30nm diameter) were found in 9 patients and microtubules (20–35 nm diameter) in the other 3. Histochemical stainings for amyloid were always negative. By light microscopy, mesangial proliferative, membranous and membranoproliferative patterns were seen in 5, 3 and 4 patients, respectively. By immunofluorescence, granular deposits, mainly of IgG and C3, were found in all cases, either in the mesangium or in the mesangium and in the capillary walls. A second biopsy was performed in 2 patients. The number of hyaline glomeruli was increased, but the general pattern of glomerular changes remained unchanged. The commonest clinical findings were hypertension, microhematuria and proteinuria, often of nephrotic range. At variance to what is reported in the literature, 2 pediatric cases were found as well, and the overall prognosis (mean follow-up 54.3 months) was mostly favorable. The diagnostic relevance of these findings is pointed out, but further investigations are needed, before suggesting a new clinicopathological entit

ISSN:0250-8095    

DOI:10.1159/000168049

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

Glomerular capillary hemodynamics influence glomerular permselectivity to macromolecules, and alterations in these factors can evoke proteinuria. Changes in hemodynamic patterns can alter protein flux by changing its diffusion- or concentration-driven movement in the presence of a constant membrane barrier. Alternatively, hemodynamic forces may disrupt, transiently or irreversibly, the permeability characteristics of the capillary barrier. Maneuvers that lower glomerular capillary pressure appear capable of reversing at least in part, these latter permeability defects. Angiotensin II, provoked by higher levels of dietary protein intake, may be a particularly important mediator of proteinuria both through its effects on diffusion-mediated protein leakage and its tendency to provoke permeability defects due to heightening of glomerular capillary hydraulic pressures.

ISSN:0250-8095    

DOI:10.1159/000168190

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

Mesangial cells are contractile pericytes of the kidney glomerulus. Mesangial contraction/relaxation contributes to the regulation of glomerular hemodynamics. Additionally, mesangial cells process filtered macromolecules, synthesize extracellular matrix, respond to and release a number of cytokines and vasoactive mediators. Cultured mesangial cells express receptors for circulating and local agents that affect glomerular function. These receptors are coupled to distinct signaling pathways, namely phospholipase C and A2, transducing vasoconstrictor stimuli, and adenylate/guanylate cyclase, transducing vasodilators. Early intracellular signals include changes of cytosolic ions and cyclic nucleotides. They translate into short-term responses, such as cell depolarization and contraction, and later events, such as prostanoid synthesis and cell proliferation. Studies of mesangial cell behavior in culture may largely enhance our current understanding of glomerular pathophysiology.

ISSN:0250-8095    

DOI:10.1159/000168191

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

A 57-year-old patient with a history of monoclonal immunoglobulin A (IgA) gammopathy developed idiopathic nephrotic syndrome. Renal biopsy showed minimal glomerular changes with predominant glomerular mesangial IgA. The association of glomerular mesangial IgA with otherwise typical minimal change nephrotic syndrome has been noted before, and the literature concerning this combination of findings is reviewed. The patient herein described represents one of the two oldest patients yet reported with this syndrome and raises questions about the relationship between minimal change disease and IgA nephropathy. Severe proteinuria (and even the nephrotic syndrome) is not necessarily the harbinger of a poor prognosis in IgA nephropathy if the glomerular morphology is otherwise consistent with minimal change nephrotic syndrome. Such patients should be treated in a fashion similar to those with minimal change nephrotic syndrome. The significance of the IgA gammopathy in the pathogenesis of this case is unknown.

ISSN:0250-8095    

DOI:10.1159/000168050

出版商:S. Karger AG    

年代:1990

数据来源: Karger