Histochemical demonstration and localization of sialoproteins in the glomerulus

Mohos, Steven C.; Skoza, L

doi:10.1016/0014-4800(70)90063-8

Cited by 49 publications

(19 citation statements)

References 14 publications

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“…It is interesting to note that all the previous works done with Epon-embedded glomeruli did not show such a feature. Furthermore, the glycoprotein coat of the foot processes in Epon sections is much thinner than that reported in the present experiment and the coat forms a continuous layer along one side of a foot process, reflecting on the surface of the slit diaphragm onto the contiguous side of the adjacent foot process [Groniowski et a!., 1969;Mohos and Skoza, 1970;Lana, 1970;Rodewald and Karnovsky, 1974], Hardly any matrix is detected in the space between the basement membrane and the slit dia phragms. Caulfield and Farquhar [1974] even stated that this represented a space where the environment is essentially aqueous and less dense than the basement membrane.…”

Section: Discussioncontrasting

confidence: 37%

Electron microscopic study of glomerular filtration barrier in the rat kidney embedded in polymerized glutaraldehyde-urea

Sobhon¹

1979

Cells Tissues Organs

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Embedding kidney in polymerized glutaraldehyde-urea favors the retention of glycoprotein matrix of the cell coat and the basement membrane of the glomeruli. The basement membrane appears as a single layer with uniform amorphous matrix. Thick glycoprotein coat covers the whole surface of prodocytes and their foot processes. In areas other than the slits and the portion of the foot processes which touch on the basement membrane, the coat is a continuous layer with an average thickness of 490 Å. In the slits between the foot processes of podocytes there is an actual fusion of glycoprotein coats; the average width of the slit is 415 Å. The glycoprotein ‘plugs’ in the slit may be a significant portion of the glomerular filtration barrier against macromolecules, together with the basement membrane and the slit diaphragms.

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Section: Discussioncontrasting

confidence: 37%

Electron microscopic study of glomerular filtration barrier in the rat kidney embedded in polymerized glutaraldehyde-urea

Sobhon¹

1979

Cells Tissues Organs

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“…The wall of the glomerular capillary has been shown to possess significant quantities of negatively charged glycosialoproteins (glomerular polyanion) (40)(41)(42)(43)(44)(45)(46), believed to constitute an electrostatic barrier to the passage of circutlating polyanions such as albumin (23,28,29,40). Therefore, the use of anionic probe macromolecules such as DS may represent more appropriate markers for the transglomerular passage of anionic proteins such as albumin than do uncharged polymers such as dextrans or polyvinylpyrrolidone.3 As is apparent from Table III, the fractional clearances of polyanionic DS molecules after PAN treatment were generally greater for any given molecular radius than values observed in normal controls, the increase being statistically significant over the range of effective DS radii from 30 to 42A.…”

Section: Discussionmentioning

confidence: 99%

Mechanisms of the Puromycin-Induced Defects in the Transglomerular Passage of Water and Macromolecules

Bohrer¹,

Baylis²,

Robertson³

et al. 1977

J. Clin. Invest.

140

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A B S T R A C T To investigate the mechanism(s) of increased filtration of serum proteins after glomerular injury, polydisperse samples of uncharged [ 42A were determined in these rats, together with direct measurements of the forces governing the glomerular filtration rate of water. Whole kidney and single nephron glomerular filtration rates were -40% lower in PAN-treated rats, relative to controls, due mainly to a marked reduction in the glomerular capillary ultrafiltration coefficient and, to a lesser extent, to a small reduction in glomerular plasma flow rate as well. In PAN-treated rats, as in normal controls, inulin was found to permeate the glomerular capillary wall without measurable restriction, and both D and DS were shown to be neither secreted nor reabsorbed. Fractional clearances of uncharged D were reduced after PAN administration, falling significantly for effective D radii from 22 to 38A. Utilizing a theory based on macromolecular transport through pores, these results indicate that in PAN-treated rats, effective pore radius is the same as in controls, -44A. In PAN nephrosis, however, the ratio of total pore surface area/pore length, a measure of pore density, is reduced to approximately one-third that of control, due very likely to a reduction in filtration surface area. In contrast to the results with uncharged D, fractional clearances of DS were found to increase after PAN

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“…Loss of such fixed negative charges has also been shown to be associated with proteinuria in several experimental glomerular diseases (2,3,7,31,32). Although anionic sites occur on the surfaces of both endothelium and epithelium (6,17,23,24,(31)(32)(33)43), the available evidence indicates that the GBM serves as both the charge and the size barrier in the filtration of macromolecules since all anionic proteins or neutral particles used as tracers (anionic ferritin [12,37], endogenous albumin [39], catalase [40], and neutral dextrans of varying size [55-78 A,] (5, 10)) do not penetrate beyond the LRI under normal flow conditions. The role of the GBM as the charge barrier was demonstrated directly by the experiments of Rennke et al (36,37) which showed that ferritin penetrates the GBM in increasing amounts the greater the isoelectric point.…”

Section: Possible Functions Of the Anionic Sitesmentioning

confidence: 99%

Anionic sites in the glomerular basement membrane. In vivo and in vitro localization to the laminae rarae by cationic probes.

Kanwar

Farquhar

1979

The Journal of Cell Biology

508

200

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Cationized ferritin (CF) of narrow pI range (7.3-7.5) and the basic dye ruthenium red (RR) have been used as cationic probes to partially characterize anionic sites previously demonstrated in the glomerular basement membrane (GBM). When CF was given i.v. to normal rats and the left kidney was fixed by perfusion 15 min thereafter, clusters of CF molecules were found throughout the lamina rara interna (LRI), lamina rara externa (LRE), and mesangial matrix distributed at regular (-60 nm) intervals. When kidneys were perfused with aldehyde fixative containing RR, small (20 nm) RR-stained particles were seen in the same locations distributed with the same 60 nm repeating pattern, forming a quasiregular, lattice-like arrangement. Fine (-3 nm) filaments connected the sites and extended between them and the membranes of adjoining endothelial and epithelial cells 9 When CF was given i.v. followed by perfusion with RR in situ, both probes localized to the same sites 9 CF remained firmly bound after prolonged perfusion with 0.1-0 9 M KCI or NaCI. It was displaced by perfusion with buffers of high ionic strength (0 9149 M KCI) or pH (<3.0 or >10.0). CF also bound (clustered at -60 nm intervals) to isolated GBM's, and binding was lost when such isolated GBM's were treated with buffers of high ionic strength or pH. These experiments demonstrate the existence of a quasi-regular, lattice-like network of anionic sites in the LRI and LRE and the mesangial matrix 9 The sites are demonstrable in vivo (by CF binding), in fixed kidneys (by RR staining), and in isolated GBM's (by CF binding). The results obtained with CF show that the binding of CF (and probably also RR) to the laminae rarae is electrostatic in nature since it is displaced by treatment with buffers of high ionic strength or pH. With RR the sites resemble in morphology and staining properties the proteoglycan particles found in connective tissue matrices and in association with basement membranes in several other locations 9 KEY WORDS cationized ferritin red proteoglycans 9 ionic interaction isolated GBM's 9 ruthenium Recent studies have shown that the glomerular capillary wall contains fixed negatively charged sites which may be important in maintaining nor- J. CELL BIOLOGY 9The Rockefeller University Press 9

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Histochemical demonstration and localization of sialoproteins in the glomerulus

Cited by 49 publications

References 14 publications

Electron microscopic study of glomerular filtration barrier in the rat kidney embedded in polymerized glutaraldehyde-urea

Electron microscopic study of glomerular filtration barrier in the rat kidney embedded in polymerized glutaraldehyde-urea

Mechanisms of the Puromycin-Induced Defects in the Transglomerular Passage of Water and Macromolecules

Anionic sites in the glomerular basement membrane. In vivo and in vitro localization to the laminae rarae by cationic probes.

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