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Anders Grubb - One of the best experts on this subject based on the ideXlab platform.

  • Urine IgG2/IgG4-ratio indicates the significance of the charge selective properties of the Glomerular Capillary wall for the macromolecular transport in Glomerular diseases.
    Nephrology dialysis transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association, 1999
    Co-Authors: Jan Tencer, Ole Torffvit, Hans Thysell, Bengt Rippe, Anders Grubb
    Abstract:

    membrane; glomerulonephritis; IgG; IgG2; IgG4; macromolecular transport; proteinuria Background. Alterations of the charge-selective properties of the Glomerular Capillary wall are important constituents of the pathogenesis of many Glomerular diseases. Thus, diVerences in the degree of such changes could be of help in understanding the mechanisms Introduction governing the transport of macromolecules across the Glomerular Capillary wall. Our understanding of the barrier function of the Methods. The ratio between urine concentrations of Glomerular filter is based on the concept of a size- and neutral IgG2 and negatively charged IgG4 charge-selectivity of the Glomerular Capillary wall. (IgG2/IgG4-ratio) was measured in 150 proteinuric Hypothetical cylindrical pores having either a continupatients and 21 healthy controls. The patients were ous distribution of pore radii or consisting of two subdivided into seven biopsy verified diagnostic populations of pores can be hypothesized to perforate groups.

  • urine igg2 igg4 ratio indicates the significance of the charge selective properties of the Glomerular Capillary wall for the macromolecular transport in Glomerular diseases
    Nephrology Dialysis Transplantation, 1999
    Co-Authors: Jan Tencer, Ole Torffvit, Hans Thysell, Bengt Rippe, Anders Grubb
    Abstract:

    membrane; glomerulonephritis; IgG; IgG2; IgG4; macromolecular transport; proteinuria Background. Alterations of the charge-selective properties of the Glomerular Capillary wall are important constituents of the pathogenesis of many Glomerular diseases. Thus, diVerences in the degree of such changes could be of help in understanding the mechanisms Introduction governing the transport of macromolecules across the Glomerular Capillary wall. Our understanding of the barrier function of the Methods. The ratio between urine concentrations of Glomerular filter is based on the concept of a size- and neutral IgG2 and negatively charged IgG4 charge-selectivity of the Glomerular Capillary wall. (IgG2/IgG4-ratio) was measured in 150 proteinuric Hypothetical cylindrical pores having either a continupatients and 21 healthy controls. The patients were ous distribution of pore radii or consisting of two subdivided into seven biopsy verified diagnostic populations of pores can be hypothesized to perforate groups.

Jan Tencer - One of the best experts on this subject based on the ideXlab platform.

  • Urine IgG2/IgG4-ratio indicates the significance of the charge selective properties of the Glomerular Capillary wall for the macromolecular transport in Glomerular diseases.
    Nephrology dialysis transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association, 1999
    Co-Authors: Jan Tencer, Ole Torffvit, Hans Thysell, Bengt Rippe, Anders Grubb
    Abstract:

    membrane; glomerulonephritis; IgG; IgG2; IgG4; macromolecular transport; proteinuria Background. Alterations of the charge-selective properties of the Glomerular Capillary wall are important constituents of the pathogenesis of many Glomerular diseases. Thus, diVerences in the degree of such changes could be of help in understanding the mechanisms Introduction governing the transport of macromolecules across the Glomerular Capillary wall. Our understanding of the barrier function of the Methods. The ratio between urine concentrations of Glomerular filter is based on the concept of a size- and neutral IgG2 and negatively charged IgG4 charge-selectivity of the Glomerular Capillary wall. (IgG2/IgG4-ratio) was measured in 150 proteinuric Hypothetical cylindrical pores having either a continupatients and 21 healthy controls. The patients were ous distribution of pore radii or consisting of two subdivided into seven biopsy verified diagnostic populations of pores can be hypothesized to perforate groups.

  • urine igg2 igg4 ratio indicates the significance of the charge selective properties of the Glomerular Capillary wall for the macromolecular transport in Glomerular diseases
    Nephrology Dialysis Transplantation, 1999
    Co-Authors: Jan Tencer, Ole Torffvit, Hans Thysell, Bengt Rippe, Anders Grubb
    Abstract:

    membrane; glomerulonephritis; IgG; IgG2; IgG4; macromolecular transport; proteinuria Background. Alterations of the charge-selective properties of the Glomerular Capillary wall are important constituents of the pathogenesis of many Glomerular diseases. Thus, diVerences in the degree of such changes could be of help in understanding the mechanisms Introduction governing the transport of macromolecules across the Glomerular Capillary wall. Our understanding of the barrier function of the Methods. The ratio between urine concentrations of Glomerular filter is based on the concept of a size- and neutral IgG2 and negatively charged IgG4 charge-selectivity of the Glomerular Capillary wall. (IgG2/IgG4-ratio) was measured in 150 proteinuric Hypothetical cylindrical pores having either a continupatients and 21 healthy controls. The patients were ous distribution of pore radii or consisting of two subdivided into seven biopsy verified diagnostic populations of pores can be hypothesized to perforate groups.

Andrea Remuzzi - One of the best experts on this subject based on the ideXlab platform.

  • Automatic generation of Glomerular Capillary topological organization.
    Microvascular research, 2001
    Co-Authors: Luca Antiga, Bogdan Ene-iordache, Giuseppe Remuzzi, Andrea Remuzzi
    Abstract:

    Glomerular structural changes are conventionally investigated by optical or electron microscopy on two-dimensional (2D) sections. To understand the relationship between functional and structural changes of Glomerular Capillary networks in more detail, three-dimensional (3D) investigation of the Capillary tufts is required. Since confocal microscopy and scanning electron microscopy cannot completely show the 3D topological organization of the Capillary tuft, we have developed an automatic method to obtain a 3D model of the Glomerular Capillary lumen structure and to derive its topological organization. Serial semithin sections of a Glomerular tuft, from rat kidney tissue, were digitized at high resolution. Capillary lumens were digitally outlined and segmented images were automatically aligned. A 3D model of the Capillary tuft was automatically generated using the Visualization Toolkit library and the Marching Cubes algorithm. We then developed an original algorithm for automatic 3D skeletonization of Capillary lumen volume to identify Capillary segments and bifurcations and to obtain the topological organization of the network and geometric parameters of Capillary segments (length, radius, and spatial configuration). Capillary segment connectivity was graphically presented in a 2D layout with an automatic procedure, revealing the lobular organization of the network. This technique, successfully applied to serial sections of a Glomerular Capillary, can be used to study a population of Glomerular capillaries to disclose the structural effects of pathological conditions. The methodology can be extended to other vascular structures, such as the microcirculation of neoplastic tissues.

  • angiotensin ii modulates Glomerular Capillary permselectivity in rat isolated perfused kidney
    Journal of The American Society of Nephrology, 1996
    Co-Authors: R Lapinski, Andrea Remuzzi, Norberto Perico, Fabio Sangalli, Ariela Benigni, G Remuzzi
    Abstract:

    Studies in experimental animals and humans have documented that inhibition of the renin-angiotensin system by angiotensin-converting enzyme inhibitors reduces urinary protein excretion rate and retards the development of renal injury. Here we sought to investigate whether angiotensin II (All) modified the size-selective properties to macromolecules of the Glomerular Capillary barrier in isolated perfused rat kidney preparation. Compared with basal values, continuous All infusion into the renal artery at the rate of 3 or 8 ng/min, but not at 0.6 ng/min, induced a progressive and significant increase in urinary protein excretion rate. Evaluation of the sieving properties of the Glomerular barrier by fractional clearance of polydisperse Ficoll showed that All significantly enhanced the filtration of tracer molecules of radil > or = 34A. All-induced changes in urinary protein excretion rate and in Ficoll fractional clearance were completely prevented by pretreatment with the specific All Type 1 receptor antagonist SR 47436.

  • Numerical analysis of blood flow in reconstructed Glomerular Capillary segments.
    Microvascular Research, 1995
    Co-Authors: Bogdan Ene Iordache, Andrea Remuzzi
    Abstract:

    Poiseuille's formula is conventionally used to calculate hydraulic resistance of blood capillaries. This law, however, applies to tubes with constant diameter and straight axis. Since blood capillaries, especially in the Glomerular microcirculation, are far from having these features, we wanted to estimate the effect of the shape of Glomerular Capillary segments on the calculation of their hydraulic resistance in comparison to the values obtained with Poiseuille's formula. We studied blood flow through Capillary segments of a reconstructed Glomerular network from a normal Munich-Wistar rat. Geometrical parameters of Capillary segments derived from serial section reconstruction of the glomerulus were used to perform numerical analysis of blood flow. Non-Newtonian properties of blood were simulated by calculating apparent blood viscosity as a function of local rheological parameters for each Capillary segment. The numerically calculated hydraulic resistances were always higher than those given by the Poiseuille equation (from 22 to 99%), and this was attributed to the geometrical complexity of the reconstructed vessels. We also performed simulations of the blood flow and filtration along the Glomerular network using a previously developed theoretical model that considers the topographical organization of the network structure and dimensions of individual Capillary segments. Considering higher hydraulic resistances (as estimated with the numerical analysis) we found that the calculated ultrafiltration coefficient did not change appreciably, but the total network pressure drop and the fraction of filtering surface area at filtration equilibrium were higher than previously estimated.

Wayne D. Comper - One of the best experts on this subject based on the ideXlab platform.

  • Do large pores in the Glomerular Capillary wall account for albuminuria in nephrotic states
    American journal of physiology. Renal physiology, 2014
    Co-Authors: Julijana Vuchkova, Maria Koltun, Kerryn A Greive, Wayne D. Comper
    Abstract:

    Albuminuria in nephrotic states is thought to arise from the formation of large pores in the Glomerular Capillary wall as large hydrodynamic probes, like Ficoll, have increased fractional clearance...

  • Albumin interaction with the Glomerular Capillary wall in vitro
    Kidney international, 1995
    Co-Authors: Yalçin Adal, Madonna F. Smit, Tanya M. Osicka, Wayne D. Comper
    Abstract:

    Albumin interaction with the Glomerular Capillary wall in vitro . The binding of albumin to the Glomerular Capillary wall was studied using albumin-gold in perfused kidneys, the interaction of [ 3 H]albumin with isolated glomeruli at 37°C and 4°C and the interaction at [ 3 H]albumin with purified basement membrane. The albumin-gold was found to bind predominantly to the basement membrane and this interaction could be dissociated with high concentrations of albumin. There was binding of albumin to isolated rat glomeruli which exhibited temperature dependence. Glomeruli exhibited a binding site at both 37°C and 4°C with an association constant in the range of 1 to 3 × 10 4 M -1 that bound 7 × 10 13 molecules/glomerulus. At 37°C, however, there was anomalous Scatchard binding behaviour at relatively higher concentrations of albumin (30 to 50 mg/ml) which could be due to either Glomerular cell uptake or the appearance of multiple binding sites or both. The binding of albumin to isolated glomeruli and the Glomerular albumin levels in isolated kidney perfusion could largely be accounted for by the binding of albumin to the Glomerular basement membrane. The albumin binding to glomeruli at 37°C was enhanced by Pronase digestion and heparinase digestion, but remained unchanged following trypsin treatment or neuraminidase treatment. Similarly, albumin was shown to bind to purified basement membrane preparations. This binding was also enhanced (˜80 times) by heparinase digestion but remained unchanged after digestion with chondroitinase ABC or hyaluronidase. The studies suggest that there is binding of albumin to the extracellular matrix components of the Glomerular Capillary wall and that a significant number of binding sites can be revealed on exposure to Pronase or heparinase. This work confirms the suggestion of Kanwar and Rosenzweig ( J Cell Biol 93:489–494, 1982) that heparan sulfate may act as an anticlogging agent to the Glomerular Capillary wall.

Enrico Reale - One of the best experts on this subject based on the ideXlab platform.

  • Elastic-like tissue, a new component of the renal Glomerular Capillary wall in a cartilaginous fish
    Anatomy and Embryology, 1991
    Co-Authors: E. R. Lacy, L. Luciano, Enrico Reale
    Abstract:

    Elastic-like tissue composed of tubular microfibrils continuous with, and disappearing into, amorphous material is present in the connective tissue space of the Glomerular Capillary wall of the river ray (freshwater elasmobranch) kidney. The amorphous material is stained by tannic acid but not by uranyl acetate. Structures with similar morphology and staining characteristics are also found in the subendothelial connective tissue layer of renal arteries in this species. Comparative ultrastructural observations of kidneys from marine rays show elastic-like tissue in the arterial wall but not in the Glomerular vessels.

  • Elastic-like tissue, a new component of the renal Glomerular Capillary wall in a cartilaginous fish
    Anatomy and Embryology, 1991
    Co-Authors: E. R. Lacy, L. Luciano, Enrico Reale
    Abstract:

    Elastic-like tissue composed of tubular microfibrils continuous with, and disappearing into, amorphous material is present in the connective tissue space of the Glomerular Capillary wall of the river ray (freshwater elasmobranch) kidney. The amorphous material is stained by tannic acid but not by uranyl acetate. Structures with similar morphology and staining characteristics are also found in the subendothelial connective tissue layer of renal arteries in this species. Comparative ultrastructural observations of kidneys from marine rays show elastic-like tissue in the arterial wall but not in the Glomerular vessels.