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Biomedical subjects

D Kerjaschki

Publications and source records attributed to D Kerjaschki.

At least 109 records · Page 6Linked to original sources
PubMed1983

Immunocytochemical localization of the Heymann nephritis antigen (GP330) in glomerular epithelial cells of normal Lewis rats.

The nephritogenic antigen of Heymann's nephritis (HN) was previously purified from tubular brush-border fractions of rat kidney and found to be a 330,000- mol-wt glycoprotein (gp330). This study was conducted to determine whether gp330 is also present in the rat glomerulus, and, if so, to establish where in the glomerulus it is located. Rabbit polyclonal and mouse monoclonal antibodies were raised against purified gp330, which specifically immunoprecipitated gp330 from solubilized brush-border fractions and specifically stained microvilli and coated invaginations (located at the base of the microvilli) of proximal tubule cells. Accordingly, they were used to localize gp330 by immunoprecipitation and immunocytochemistry in glomeruli of normal Lewis rats. For immunoprecipitation, purified glomerular fractions were prepared from [(35)S]-methionine-labeled kidneys, extracted with Triton X-100, and the extract was used for immunoprecipitation with affinity-purified rabbit polyclonal, or mouse monoclonal, anti-gp330 IgG. Analysis of immunoprecipitates by sodium dodecyl sulfate-polyacrylamide gel electrophoresis fluorography indicated that a band corresponding in mobility to gp330 was specifically precipitated. When unfixed cryostat sections were incubated for indirect immunofluorescence with monoclonal or affinity-purified polyclonal IgG, a fine granular fluorescent staining was seen throughout the glomerulus. When aldehyde-fixed cryostat sections were incubated for indirect immunoperoxidase, reaction product was detected only in the epithelial cells and was not seen in the GBM, endothelium, or mesangium. Within the epithelium it was localized to the endoplasmic reticulum, occasional Golgi elements, multivesicular bodies, and coated pits at the cell surface. The reactive coated pits were distributed all along the cell membrane, including the sides and base of the foot processes. Reaction product was detected in the latter location only in sections that had been digested with neuraminidase before antibody incubation. When rats were given rabbit anti-gp330 IgG by intravenous injection and their kidneys stained for direct immunoperoxidase 3 d later, rabbit IgG was seen to be deposited beneath the slit diaphragms and in the coated pits at the base of the foot processes. The immunocytochemical and immunoprecipitation data indicate, in confirmation of the results of others, that the nephritogenic HN antigen is present in renal glomeruli as well as in proximal tubular brush borders. The immunocytochemical results further demonstrate that gp330 is an epithelial, rather than a glomerular basement membrane, antigen. It appears to be synthesized by glomerular epithelial cells and subsequently becomes concentrated in coated pits. As both the endogenous antigen (gp330) and exogenously administered anti-gp330 antibody were localized to coated pits, it seems likely that coated pits located at the base of the foot processes are the sites where the HN antigen (gp330) and circulating antibodies directed against gp330 meet and where immune complexes are formed.

Animals↗
PubMed1982

The pathogenic antigen of Heymann nephritis is a membrane glycoprotein of the renal proximal tubule brush border.

Purified brush border fractions prepared from rat kidneys were solubilized in detergent, iodinated, and subjected to immunoprecipitation to identify the pathogenic antigen present in brush border membranes that is responsible for the production of Heymann nephritis (HN). Purified IgG prepared from the sera of rabbits or rats immunized with a crude cortical preparation, known as Fx1A, precipitated multiple peptides, whereas IgG eluted from glomeruli of rats with active or passive HN specifically immunoprecipitated a single large glycoprotein (Mr = 330,000). This protein (gp330) was subsequently purified by gel filtration and lentil lectin affinity chromatography from detergent-solubilized brush border membranes. When rats were immunized with purified gp330, they developed anti-brush border antibodies and active HN. IgG prepared from the serum of rats with active HN caused passive HN when injected into normal recipients. Rats immunized against brush border membrane proteins depleted of gp330 developed anti-brush border antibodies but did not develop HN. Further analysis of gp330 indicated that it is solubilized by detergent treatment of isolated brush border microvilli, and its antigenic component is released from intact microvilli by trypsin. By immunoperoxidase staining it was localized to the luminal side of the brush border membranes. These results indicate that (i) gp330 is the pathogenic antigen of HN; (ii) the antigen is a glycoprotein of the brush border membrane; and (iii) it is disposed with its pathogenic domain(s) facing the tubule lumen.

Animals↗
PubMed1981

Partial rat kidney resection using autologous fibrinogen thrombin adhesive system.

The Fibrinogen Thrombin Adhesive System (FTAS) enables local haemostasis to occur in parenchymatous organs without tissue damage. The aim of this study was to investigate the degradation of FTAS and the process of wound healing after partial kidney resection in rats using FTAS for induction of local haemostasis. In 28 rats partial kidney resection was performed bilaterally. Haemostasis was achieved with Fibrinogen Thrombin Adhesive System. Four experimental groups were formed. Group A (n = 3): Haemostasis with unlabelled FTAS, subcutaneous injection of 0.1 ml = 60 mu Ci Na 125I. Group B (n = 3): Haemostasis with unlabelled FTAS, subcutaneous injection of 0.1 ml = 60 mu Ci 125I FTAS. Group C (n = 6): Haemostasis with 125I labelled FTAS. Group D (n = 16): treated like Group C. In Groups A - C 125I-elimination in 24 h urine samples was determined with a gamma-scintillation counter. Pairs of animals in Group D were killed after 2, 6, 12 and 24 h and 3, 7, 14 and 21 days. Kidneys were examined under the light and electron microscope and by autoradiography. In animals of Groups B and C two peaks of 125I excretion were observed: one peak within the first 48 h postoperatively which corresponded to the amount of free iodine injected with FTAS (FTAS contains 15% free iodine); a second peak after 120 h which was most probably due to the degradation of FTAS. Fibrinolysis was not observed. FTAS was resorbed mainly by macrophages. The time course of wound healing paralleled that of physiological fibrinogen concentration. Renal parenchymal damage was not observed.

Animals↗
PubMed1979

Formation and involution of Mallory bodies ("alcoholic hyalin") in murine and human liver revealed by immunofluorescence microscopy with antibodies to prekeratin.

Antibodies raised against prekeratin intensely and specifically stain, in immunofluorescence microscopy, Mallory bodies ("alcoholic hyalin") present in livers of human alcoholics and griseofulyin-treated mice. The high sensitivity of this method allows the identification of small distinct cytoplasmic structures that are observed during early stages of Mallory body formation, especially frequent in the perinuclear cytoplasm, as well as during stages of Mallory body disintegration and disappearance, such as after withdrawal of the drug. In the latter situation, the prekeratin-containing small particles exhibit a characteristic pattern of arrangement in the hepatocyte periphery. Electron microscopy illustrates that such small bodies are heap-like aggregates of typical Mallory body filaments. Immunofluorescence studies with antibodies to isolated prekeratin polypeptides from bovine hoof or muzzle epidermis show that Mallory body filaments, in particular those in human liver, are immunologically more closely related to prekeratin of tonofilaments from living epidermal cells (stratum spinosum). The data indicate that Mallory bodies contain a pathologic form of prekeratin-like material. They also suggest that disorders of cytoskeletal structures of the intermediate-sized filament class are associated with specific diseases and can be visualized and characterized by immunofluorescence microscopy by using antibodies to constitutive proteins of such filaments.

Animals↗
PubMed1979

Interference of tris(hydroxymethyl)aminomethane with structure and function of Golgi membranes.

Short term perfusion of isolated rat liver with tris(hydroxymethyl)aminomethane or other nonamphoteric amines (glycine amide, diethylamine) in moderate concentrations (10 to 20 micron) causes blistering of Golgi stacks on the concave side as well as swelling of lysosomes and of secretory vesicles in otherwise unaltered hepatocytes. Similar vacuolization is observed in Kupffer cells, pancreatic beta-cells, intestinal epithelial cells, and renal proximal tubule cells, but not in alpha-cells of the pancreas or in kidney glomerular podocytes. Fusion of the vesicles occurs frequently and involves denudation of intramembranous particles from contact areas. Since protein synthesis is not affected, inhibition by tris(hydroxymethyl)aminomethane of protein secretion into the perfusate indicates a block in protein processing at a postribosomal level. This finding together with morphologic evidence unravels the Golgi and post-Golgi membranes as specific site of tris(hydroxymethyl)aminomethane interaction with intracellular structures.

Animals↗
PubMed1979

The structure of tight junctions in human thyroid tumors. A systematic freeze-fracture study.

Tight junctions of normal human epithelium comprise 6--8 intramembranous ridges. Tight junctions of adenomas and one case of follicular carcinoma were morphologically identical with normal controls. Another follicular carcinoma (clinically less malignant than the case mentioned above), however, showed loss of junctional polarity with spreading of ridges on lateral cell membranes. One case of papillary carcinoma (clinically low malignancy) displayed only focal attenuations of the tight junction belt. Another more malignant tumor of the same histologic type showed breaks of ridges and focal interruptions of the tight junction meshwork. Cell membranes of two anaplastic carcinomas of high malignancy were completely devoid of tight junction ridges. We conclude that tight junction alterations are not necessarily implicated in malignant transformation and that they correspond with tumor differentiation rather than directly with a single parameter of thyroid tumor malignancy.

Adenocarcinoma↗
PubMed1978

[Recurrence of intramembraneous glomerulonephritis in 2 consecutive kidney transplantations].

A case of dense intramembranous deposit disease, partial lipodystrophy, hypocomplementemia, and nephritic factor-like activity in the serum is presented. Recurrence of underlying renal disease was noted in two consecutive renal allografts. The first transplant was lost 7 months after implantation, chronic renal rejection being an additional cause of graft failure. A favourable clinical course, however, was observed after the second renal transplantation. 22 months after surgery, the patient was fully rehabilitated and transplant function only slightly reduced despite electron microscopic evidence of typical dense intramembranous deposit lesions. Low C3-serum complement and normal C4-serum complement levels were constant findings throughout observation time. The case supports the assumption that patients with dense intramembranous deposit disease should not be excluded from renal transplantation As shown in the literature, maintenance of satisfactory graft function is usually obtained for a long period of time despite recurrence of original disease.

Adult↗
PubMed1978

Polycation-induced dislocation of slit diaphragms and formation of cell junctions in rat kidney glomeruli: the effects of low temperature, divalent cations, colchicine, and cytochalasin B.

Neutralization of negatively charged groups in the glomerular capillary wall by polycations causes extensive loss of podocyte footplates, formation of tight and gap junctions, and dislocation of slit diaphragms within a few minutes (M. W. Seiler, M. A. Venkatachalam, and R. S. Cotran: Science 189:390, 1975). This study attempts to elucidate further the development of podocyte abnormalities by quantitating the effects of inhibitors of microfilaments, microtubules, and cellular metabolism. The decrease in the number of footplates per micrometer of basement membrane caused by the polycationic chemical protamine sulfate (PS) was determined after in situ perfusion of the left kidney of rats. An approximate 50 per cent amelioration of this effect of PS was observed when in addition to perfusion with PS: (1) perfusion was performed in the cold (6 degrees C.); (2) the perfusate contained cytochalasin B; (3) the perfusate lacked Ca2+; and (4) the perfusate contained ethylenediaminetetraacetic acid. In contrast, colchicine did not affect PS-induced footplate loss. It was concluded that the PS-induced footplate retraction observed in scanning micrographs, is partially an active process involving podocyte actin filaments. Intact microtubuli are obviously not necessary. Formation of tight and gap junctions between foot processes and dislocation of slit diaphragms were not influenced by any of the inhibitory conditions listed above.

Animals↗
PubMed1976

The central tubuli in distal segments of olfactory cilia lack dynein arms.

By means of the tannic acid-glutaraldehyde fixation method, the lack of dynein bridges between the central two tubuli in distal segments of mouse olfactory cilia is demonstrated. Consequently, these organelles are supposed to be unable to beat actively, in contrast to the proximal ciliary shafts.

Animals↗
PubMed1975

[Some aspects of biological membranes: concepts and techniques (author's transl)].

Some of the abundant data on the structure of biological membranes are compiled in this short review, with particular emphasis on morphological techniques. The "fluid mosaic" model of biological membranes has rapidly gained importance as the fundamental concept. According to this model, protein particles swim in a lipid bilayer, whose molecules are ordered with their hydrophilic end outside and their hydrophobic tail inside the membrane. Proteins are spatially stabilized and actively moved by a submembranous net of fibrillar proteins. Information about the orientation of protein molecules within the bilayer is obtained by protein labelling with membrane impermeable compounds and subsequent gel-electrophoretic separation of the solubilized components. Freeze etching brings to light intramembranous particles which are probably segments of the membrane proteins that stand out from the plane of the split hydrophobic membrane interface. By this method the morphology of cell contacts, for example, can be analyzed and comprehended at a supramolecular level. Special techniques such as observation of both matching sites of the split membrane halves or deep etching (whereby the actual surface of membrane is exposed) may provide further valuable contributions to the rapidly expanding field of membranology.

Basement Membrane↗