Absorption and transport of ferritin and exogenous horseradish peroxidase in the opisthonephric kidney of the sea lamprey. I. The renal corpuscle

1975 ◽  
Vol 53 (5) ◽  
pp. 571-581 ◽  
Author(s):  
John H. Youson

The single, elongate renal corpuscle in the opisthonephros of the sea lamprey deals with exogenous protein tracers in much the same manner as the renal corpuscles in the kidneys of higher vertebrates. Horseradish peroxidase readily diffuses from the capillaries through the mesangium, basement membrane, and slit diaphragms of the visceral epithelium into the urinary space, where it is transported to the tubule. Ferritin diffuses more slowly but follows a similar pathway. Protein tracers which come in contact with the visceral and parietal epithelium, either through diffusion from the circulation or after direct introduction of these substances into the urinary space, are readily absorbed by both types of epithelium. Permeability of the parietal epithelium is suggested by the presence of the tracers in intercellular spaces. The localization of these tracers in the urinary space and epithelial cells both anterior and posterior to the site of their introduction suggests that the elongate glomus is surrounded by a single tortuous urinary space resulting from the continuity of the capsules.

1966 ◽  
Vol 124 (6) ◽  
pp. 1123-1134 ◽  
Author(s):  
Richard C. Graham ◽  
Morris J. Karnovsky

1. Glomerular permeability was studied by ultrastructural cytochemistry, using as protein tracers two intravenously injected peroxidases of differing molecular weight. 2. Horseradish peroxidase (molecular weight 40,000) passed rapidly through the endothelial fenestrae, across the basement membrane, and through the epithelial slits into the urinary space. Human myeloperoxidase (molecular weight 160,000 to 180,000) also passed rapidly through the endothelial fenestrae and across the basement membrane, but was impeded at the level of the epithelial slits. Both proteins were taken up in large amounts by the mesangial cells. 3. The present findings indicate that the epithelial slits are the primary filtration barrier responsible for the differential permeability to proteins of varying molecular size. 4. The observations also support the concept that an important function of the mesangial cells is the incorporation and disposal of glomerular filtration residues.


1970 ◽  
Vol 132 (6) ◽  
pp. 1153-1167 ◽  
Author(s):  
M. A. Venkatachalam ◽  
M. J. Karnovsky ◽  
H. D. Fahimi ◽  
R. S. Cotran

Mice were injected intravenously with beef liver catalase (mol wt 240,000) and very small doses of horseradish peroxidase (mol wt 40,000) and the site of localization of these enzymes in the kidney was studied by ultrastructural cytochemistry. 1 min after injection, catalase was present in glomerular capillary lumina and there was minimal permeation of the basement membrane. After 5–180 min, staining of the basement membrane increased progressively but was usually less than that in capillary lumina. At all time intervals the inner (sub-endothelial) layer of the basement membrane contained more reaction product than the lamina densa and the outer (subepithelial) layer. Catalase permeated the entire thickness of the basement membrane and extended up to the slit pore but not beyond the level of the slit diaphragm and was not seen in the urinary space or tubular lumina. Horseradish peroxidase permeated the whole thickness of the basement membrane within 2 min after injection; however, gradients of staining from the inner to outer layers of the basement membrane were frequently seen. The findings with both enzymes indicate that (a) the basement membrane restricts the passage of proteins over a wide range of molecular size with increasing impediment for larger molecules and (b) the slit pore functions as an additional barrier for molecules that cross the basement membrane.


1997 ◽  
Vol 106 (5) ◽  
pp. 394-398 ◽  
Author(s):  
Kensuke Watanabe ◽  
Yasuo Tanaka

Escherichia coli-derived endotoxin was inoculated in the middle ear of guinea pigs 24 hours after being injected intraperitoneally. Twenty-four hours after the middle ear inoculation, horseradish peroxidase (HRP) was injected via the femoral vein and the permeability of HRP through the capillaries of the stria vascularis and the destination of the leaked HRP were examined. A large amount of HRP leaked out of the capillary through the opened endothelial cell junctions and penetrated the enlarged intercellular spaces. Leaked HRP entered the pinocytotic vesicles of the intermediate cells. Even slightly degenerated intermediate cells retained this function. The HRP penetrated the spongelike structure of the marginal cells leading to the intercellular space. This structure was not observed without endotoxin. The HRP could not pass to the cochlear duct through the tight junctions between marginal cells. Blood sludging was observed in the strial capillaries. It appeared more frequently in the upper three turns than in the basal turn. The HRP leakage out of the capillaries was observed not only in the upper three turns but also in the basal turn.


1965 ◽  
Vol 32 (1) ◽  
pp. 44-50
Author(s):  
Antti Paalanen

This study comprises some observations about the structure of the connective tissue of the basement membrane and interstitium in some normal, post-natal human kidneys. The basis of the basement membrane is mainly a reticular, homogeneous membrane that belongs uniformly to both Bowman's capsule and the wall of the renal tubule. Outside it in the capsule is a durable collagenic membrane whose development must be considered and evincement of functional adaptation under the pressure conditions of the cavity. In renal tubules there is no such well-defined outer membrane, but in them the basement membrane has in addition collagenic traits to some extent and is thus reticular-collagenic when examined as a whole. The renal tubules are surrounded by a dense, spiraling reticular network of fibres which attaches to the connective tissue of the interstitium where fibrocytes are scarce. The network extends all the way around the renal corpuscle. There is no elastic tissue at all in the basement membranes.


1967 ◽  
Vol 34 (2) ◽  
pp. 617-626 ◽  
Author(s):  
Arnaldo Lasansky

The hyaloid vessels form a capillary network on the inner surface of the retina. These capillaries are embedded in the vitreous humor, and they lack a glial investment. The intercellular spaces of the retina communicate with the ocular cavity, as can be evidenced by following the penetration of tracer substances. Hence, there is an extracellular diffusion pathway between hyaloid capillaries and retinal neurons, without interposition of glial cells. Trypan blue and ferrocyanide were not detected within the vitreous humor nor the retina after systemic injection. To this extent, at least, the hyaloid capillaries functionally resemble central nervous system capillaries. Intravascular injections of horseradish peroxidase established the absence of vesicular transfer across the endothelium of the hyaloid capillaries. In addition, quintuple-layered junctions between endothelial cells prevented the intercellular passage of the enzyme. It is likely, therefore, that the only pathway across the endothelium of the hyaloid capillaries is through the plasmalemma of the endothelial cells.


2011 ◽  
Vol 21 (3) ◽  
pp. 151
Author(s):  
Terry M Mayhew

The renal corpuscle is a multi-compartment unit of kidney morphology which is important for normal ultrafiltration of blood. Its structure is perturbed during ontogeny, disease and experimental manipulation. Transmission electron microscopy and second-order stereological tools (cross covariance and cross correlation functions) were used to examine 3-D spatial interactions between the main tissue compartments (glomerular capillaries, podocytes, mesangium, urinary space) of the renal corpuscle in normal adult rats. Volume densities, covariance and correlation functions were estimated by counting test points (randomly positioned) and linear dipole probes (randomly positioned and orientated) superimposed on random samples of photomontages prepared from ultrathin resin sections. Differences in clustering exist between compartments (at distances < 8 μm, mesangium is the most tightly-clustered and capillaries the least tightly-clustered compartment; > 8 μm, compartments are neither hypodisperse nor hyperdisperse). Despite this, cross correlation functions for linked sets of compartments (capillary-mesangium, capillary-podocytes, capillary-urinary space, mesangium-podocytes, mesangium-urinary space and podocytes-urinary space) did not vary with dipole distance. This indicates that the spatial relations between linked compartments do not favour attraction or repulsion. In addition, inter-individual variation is greater for some linked compartments than others. Variation is less for compartments (capillary-podocyte and capillary-urinary space) which contribute to the ultrafiltration barrier and this probably reflects the structural and functional integration evident at this site as well as the higher volume densities (and smaller inter-subject variation) for capillaries.


1974 ◽  
Vol 139 (5) ◽  
pp. 1283-1302 ◽  
Author(s):  
E. E. Schneeberger ◽  
P. D. Leber ◽  
M. J. Karnovsky ◽  
R. T. McCluskey

The altered functional properties of the glomerular capillary wall in a model of autologous immune complex disease (Heymann's nephritis) was studied by electron microscopy using intravenously injected protein tracers of varying molecular weight. There was an increase in the permeability of the glomerular basement membrane (GBM) itself to large molecules; this change was focal and was found in those areas where the GBM contained immune complex deposits. Both ferritin and catalase, tracers normally restricted from passing the glomerular filter, were present in the urinary space within minutes of injection. No evidence was obtained for increased glomerular epithelial transport in this disease. Foot process swelling and "close" junction formation was moderate, even in animals with marked degrees of proteinuria. Indirect evidence, therefore, makes an alteration in the slit pore complex likely. In addition, there was immediate and selective concentration of all tracers within deposits, though ferritin was partially excluded from some deposits. This phenomenon may be of significance in the perpetuation of the disease.


Author(s):  
Sarah Hunt ◽  
Yoav Segal ◽  
Kevin D. Dorfman ◽  
Victor H. Barocas

Transport in the kidney is critically important in normal function and in disease. Solute transport occurs in many locations within the kidney, including convection within the capillaries, filtration across the basement membrane, and convection/diffusion within the mesangium (Figure 1). Models of transport in the kidney have traditionally focused on ultrafiltration [1], which is the predominant pathway for fluid and solutes passing into the urinary space. However, the mesangium is often the site of the first symptoms in disease [2], suggesting that mesangial transport is significant, at least in some cases.


2020 ◽  
pp. 23-27
Author(s):  
В. В. Елагин ◽  
Д. А. Костина ◽  
О. И. Братчиков ◽  
Т. Г. Покровская ◽  
С. Л. Кузнецов ◽  
...  

Цель - выявить и изучить степень выраженности морфологических изменений структур коркового и мозгового вещества почки на фоне смоделированной билатеральной модели ишемии-реперфузии. Материал и методы. Эксперименты проведены на 50 крысах-самцах линии Вистар массой 180-220 г. Моделирование билатеральной модели ишемии-реперфузии проводилось путем наложения атравматичных зажимов на обе почечные ножки на 40 мин. Через 24 или 72 ч реперфузии проводили оценку выраженности структурных изменений в корковом и мозговом веществе почки с использованием гистологических и морфометрических методик. Измеряли высоту эпителиоцитов в проксимальном и дистальном извитых канальцах нефрона, площадь поперечного сечения почечного тельца, клубочка и капсулярного пространства. Результаты. Полученные морфологические изменения в виде нарушения структурности эпителия как в корковом, так и в мозговом веществе почки на 1-е сутки эксперимента имеют тенденцию к увеличению степени их выраженности. К 3-м суткам эксперимента наиболее выраженные реактивно-деструктивные изменения визуализируются в реабсорбционносекреторных отделах нефрона, которые проявляются в виде снижения высоты эпителиоцитов проксимальных и дистальных канальцев, отслоением их от базальной мембраны и слущиванием. Усугубление схожей морфологической картины происходило в собирательных трубках, в просветах которых определялись конгломераты из отслоившихся от базальной мембраны погибших клеток эпителия. Выявленные реактивно-деструктивные изменения в почках морфологически обосновывают адекватность создания модели ишемии-реперфузии. Выводы. 40-минутная билатеральная ишемия почек с последующей реперфузией в течение 1-3 сут приводит к выраженным структурным изменениям в почках, что соответствует характеристике острого почечного повреждения. Objective - to identify and study the severity of morphological changes in the structures of the renal cortex and medulla in the bilateral model of ischemia-reperfusion. Material and methods. The experiments were performed on 50 male Wistar rats weighing 180-220 grams. A bilateral ischemia-reperfusion was modelled by applying atraumatic clamps to both kidney pedicles for 40 minutes. After 24 or 72 hours of reperfusion, the severity of structural changes in the renal cortex and medulla was assessed using histological and morphometric techniques. The height of epithelial cells in the proximal and distal convoluted tubules of the nephron, the cross-sectional area of the renal corpuscle, glomerulus and capsular space were measured. Results. Severe structural changes in the renal tissue affecting both the tubular and glomerular apparatus of the kidneys were found, with the increase in pathological changes from the first to the third days of the experiment in the form of a decrease in the epithelial height of the distal and proximal tubules, as well as a decrease in the area of the renal corpuscle and vascular glomerulus. The morphological changes in the form of a structural damage of the epithelium of both renal cortex and medulla were detected on the 1st day of the experiment, and they tend to increase their severity. By the 3rd day of the experiment, the most pronounced reactive-destructive changes were visualized in the reabsorption-secretory sections of the nephron. They were manifested as a decrease in the height of the proximal and distal tubule epithelial cells, their exfoliation from the basement membrane and desquamation. The similar but more aggravated morphological picture was seen in collecting tubes, where conglomerates of dead epithelial cells exfoliated from the basement membrane were found in the gaps. The revealed reactive-destructive changes in the kidneys morphologically substantiate the adequacy of creating a model of ischemia-reperfusion. Conclusions. A 40-minute bilateral renal ischemia followed by reperfusion leads to severe structural changes in the kidneys in 1-3 days, which corresponds to a characteristic of acute renal damage.


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