PubMed Health⌕ Search

Biomedical subjects

H Holthöfer

Publications and source records attributed to H Holthöfer.

At least 73 records · Page 4Linked to original sources
PubMed1990

Polycystic disease of the kidney. Evaluation and classification based on nephron segment and cell-type specific markers.

The usefulness of various segment and cell-type specific antibody, lectin and functional markers in the study of cystic renal lesions was evaluated. For this purpose, kidneys from recessive polycystic kidney disease (RPKD), thought to involve mainly the collecting ducts, and cystic kidneys of Meckel's syndrome (MS), which show dilation randomly along the nephron, were studied. The segment (and differentiation-stage)-specific anti-brush-border (specific for proximal tubules) antibodies stained morphologically normal proximal tubules, failed to react with cyst wall epithelium in RPKD, but readily stained some cysts in MS. Immunostaining for Tamm-Horsfall glycoprotein (distal tubules) similarly revealed normal tubular profiles, and also stained moderately dilated tubules, but not the large cysts in either disease type. Lectin markers of the distal tubules and collecting ducts (peanut agglutinin, Helix pomatia agglutinin and Dolichos biflorus agglutinin) reacted with both dilated tubules and with the cyst walls in RPKD and Meckel kidneys, suggesting that in RPKD, the dilations also occur in the distal nephron in addition to the collecting duct, and in MS in any part of the renal tubule. The cell type-specific functional marker of the collecting duct, anti-NaK-ATPase reactivity (found in principal cells) could be seen in RPKD but not in Meckel kidney cysts, suggesting a minor involvement of principal cells in MS. Consistent with this, only occasional carbonic anhydrase (found in intercalated cells) or band 3 (bicarbonate-chloride exchanger molecule of intercalated cells) of collecting ducts positive cells in the cysts could be seen, suggesting that intercalated cells are only sparsely seen in these lesions. The results show the usefulness of a panel of independent markers in studying the segment, cell-type and function-specific features of renal cystic lesions as a basis for their classification.

Biomarkers↗
PubMed1989

Antibodies against gastrointestinal carcinoid tumors in IDDM.

In this study, 92% of patients' serums known to contain antibodies against islet cells, including the Juvenile Diabetes Foundation provisional reference serum, had antibodies reacting with gastrointestinal carcinoid tumors. Twelve percent of the control serums from healthy individuals bound to carcinoid cells, and 2% bound to islet cells. Seventy-five percent of the children with newly diagnosed insulin-dependent diabetes mellitus had carcinoid tumor antibodies, and 83% had islet cell antibodies. These findings suggest that antigenic determinants are shared between endocrine cells of islets of Langerhans and neuroendocrine tumors of the same embryological derivation. Carcinoid tumors may not only provide an alternative source for islet cell antibody assays but also supply material for isolation of antigens possibly involved in the immunopathogenesis of diabetes.

Adult↗
PubMed1988

Cell type-specific glycoconjugates of collecting duct cells during maturation of the rat kidney.

The ontogeny of lectin-positive epithelial cell types and the maturation of polarized expression of the glycocalyx of the collecting ducts (CD) of the rat kidney were studied from samples of 18th-day fetal and neonatal kidneys of various ages. Lectins from Dolichos biflorus (DBA) and Vicia villosa (VVA), with preferential affinity to principal cells, stained virtually all CD cells of the fetal kidneys. However, within two days postnatally, the number of cells positive for DBA and VVA decreased to amounts found in the adult kidneys. Moreover, a characteristic change occurred rapidly after birth in the intracellular polarization of the reactive glycoconjugates, from a uniform plasmalemmal to a preferentially apical staining. In contrast, lectins from Arachis hypogaea (PNA), Maclura pomifera (MPA) and Lotus tetragonolobus (LTA), reacting indiscriminatively with principal and intercalated cells of adult kidneys, stained most CD cells in the fetal kidneys, and failed to show any postnatal change in the amount of positive cells or in the intracellular polarization. The immunocytochemical tests for (Na + K)-ATPase and carbonic anhydrase (CA II) revealed the characteristic postnatal decrease in the amount of principal cells and simultaneous increase in the amount of CA II rich intercalated cells. DBA and VVA reactive cells also decreased postnatally, paralleling the changes observed in the (Na + K)-ATPase positive principal cells. The present results suggest that the expression of the cell type-specific glycocalyx of principal and intercalated cells is developmentally regulated, undergoes profound changes during maturation, and is most likely associated with electrolyte transport phenomena.

Animals↗
PubMed1988

Heterogeneity of apical glycoconjugates in kidney collecting ducts: further studies using simultaneous detection of lectin binding sites and immunocytochemical detection of key transport enzymes.

In the search for a functional role for the polarized glycoconjugates of rat collecting duct epithelial cells, the relation between binding of various lectins and expression of cellular transport enzyme profile of the cells was studied. For this purpose, principal and intercalated cells of rat kidney collecting duct were identified by morphological criteria and by their immunocytochemically determined content of (Na+ + K+)-ATPase and carbonic anhydrase (CA II), respectively. Various N-acetylgalactosamine-specific lectins such as those from Helix pomatia and Maclura pomifera revealed heterogeneity among both principal and intercalated cells, whereas alpha-N-acetylgalactosamine-specific lectin from Dolichos biflorus and Vicia villosa bound preferentially to principal cells. Still another lectin from Arachis hypogaea reacted with most collecting duct cells in the cortex and outer medulla, but only with a subpopulation of cells in the inner medulla. Interestingly, some lectins reacted exclusively with the apical aspect of the collecting duct epithelial cells, whereas others revealed both an apical and basolateral distribution of lectin reactive glycoconjugates. The results thus show subtle differences in the glycocalyx structure of principal and intercalated cells and differences in the intracellular polarization of glycoconjugates of these cells. Thus, lectins may be useful tools in the study of the molecular mechanisms which establish and maintain the polarized functions of principal and intercalated cells.

Animals↗
PubMed1988

Glomerular sialoconjugates of developing and mature rat kidneys.

The appearance of sialoconjugates in developing rat kidney glomeruli was studied using lectins and neuraminidase-lectin staining sequences. In the early S-shaped bodies, binding of Maclura pomifera (MPA; specific for galactosaminyl residues of glycoconjugates) could be detected in the presumptive podocyte layer at the apex of these cells, but notably no binding of lectins specific for sialic acid could be seen. During further morphologic maturation of the S-shaped bodies, binding of Limax flavus (LFA; specific for sialic acids) and Triticum vulgaris (WGA; specific for sialic acids and N-acetyl glucosaminyl moieties) appeared at the apex of podocytes and extended subsequently along the lateral membranes to the base of these cells. In morphologically mature glomeruli, LFA stained not only the base of podocytes but also glomerular basement membranes. WGA and MPA bound to the capillary endothelia as well as to the structures bound by LFA. The intensity of WGA binding increased considerably after 5 days of postnatal life, seemingly in parallel with the decrease and ultimate disappearance of MPA binding. In addition to showing individual appearance pattern for various lectin binding sites, these studies give evidence of previously unrecognized postnatal completion of the components of glomerular filtration barrier.

Animals↗
PubMed1988

Binding characteristics of Escherichia coli adhesins in human urinary bladder.

We studied domains in the human bladder that acted as receptors for Escherichia coli P, S, type 1, type 1C, and O75X fimbriae or adhesin and domains in the human kidneys that were receptors for E. coli type 1C fimbriae. Binding sites in frozen tissue sections were localized by direct staining with fluorochrome-labeled recombinant strains and by indirect immunofluorescence with the purified adhesins. In the bladder, the P and S fimbriae showed closely similar binding to the epithelial and muscular layers, and the S fimbriae also bound to the connective tissue elements. Type 1 fimbriae bound to vascular walls and to muscle cells, whereas the O75X adhesin bound avidly to connective tissue elements and to some extent to epithelial and muscle cells of the bladder. The type 1C fimbriae bound to distal tubules and collecting ducts of the kidney and to vascular endothelial cells in both the kidney and bladder. The binding of all adhesin types was inhibited by specific receptor analogs or Fab fragments. The results reveal a possible mechanism by which the type 1C fimbriae may help invasion of E. coli in the kidneys but do not support a pathogenetic role for type 1 fimbriae. Similar tissue specificity of P and S fimbriae in the human urinary tract indicates that the presence of binding sites on uroepithelia does not fully explain the virulence properties of P fimbriae in human urinary tract infections.

Adhesins, Escherichia coli↗
PubMed1987

Expression of binding sites for Dolichos biflorus agglutinin at the apical aspect of collecting duct cells in rat kidney.

To identify precisely the structural and functional cell type in the collecting duct of the rat kidney expressing binding sites for Dolichos biflorus agglutinin (DBA), we stained serial paraffin sections of kidney with horseradish peroxidase-labeled DBA and with immunocytochemical methods for localizing (Na+ + K+)-ATPase and carbonic anhydrase II (CA II), enzymes found preferentially in principal and intercalated cells, respectively. Most principal cells expressing a strong basolateral staining for (Na+ + K+)-ATPase showed binding sites for DBA at their luminal surfaces. However, a minority of cells rich in CA II and showing morphologic characteristics of intercalated cells also expressed DBA binding sites at their luminal surface and apical cytoplasm. These data suggest that DBA cytochemistry can provide a useful tool for studying the functional polarity of the main cell types of the collecting duct of the rat kidney.

Animals↗
PubMed1987

Renal oncocytoma: immuno- and carbohydrate histochemical characterization.

Samples from renal and thyroid oncocytomas were studied with antibodies against intermediate filament proteins, nephron site specific antigens and nephron segment specific lectins to gather information on the immunohistological and carbohydrate histochemical features of these tumours. The results show a surprising failure of most antibodies and lectins used to react with the oncocytomas, although readily staining the surrounding normal tissue areas. No immunohistological evidence for derivation of oncocytomas from proximal tubular epithelial cells could thus be found. Instead, Triticum vulgaris (wheat germ agglutinin; WGA) and Concanavalin A (ConA) lectins were seen to stain the oncocytes specifically, suggesting that these lectins are useful to further characterize oncocytomas.

Adenoma↗
PubMed1987

Vascularization of the embryonic kidney. Detection of endothelial cells with Ulex europaeus I lectin.

Frozen sections of human fetal kidneys were studied for the appearance of vascular elements to the developing glomeruli using Ulex europaeus (UEA-I) lectin as a marker for endothelial cells. Chains of UEA-I-positive cells, seen to extend from larger vessels, could be observed among the uninduced cells of the nephrogenic mesenchyme. During the S-shaped body stage of nephrogenesis, the cleft of the comma-shaped cluster of epithelial cells was invaded by the UEA-I-positive cells, and during further glomerular development, the UEA-I-positive cells were seen to grow in number, prior to the appearance of visible lumina to the capillaries. The present results show, in addition to revealing the vascularization pattern of developing glomeruli, that endothelial cells obtain some of their characteristic glycoconjugates during early stages of differentiation. Thus, UEA-I seems to be a valuable tool to study in detail the vascularization of various developing human tissues.

Capillaries↗
PubMed1987

The O75X adhesin of uropathogenic Escherichia coli: receptor-active domains in the canine urinary tract and in-vitro interaction with laminin.

The complementary binding sites for the purified O75X adhesin of uropathogenic Escherichia coli in canine urinary tract were determined by indirect immunofluorescence. The adhesin bound to the vascular basement membranes in the canine kidney, ureter, bladder and urethra. In the kidney, the adhesin bound also to the tubular basement membranes and to the Bowman's capsule and mesangium of the glomeruli. In the bladder and ureter, but not in the urethra, the O75X adhesin bound to the basal lamina of smooth muscle cells. Connective tissue was negative for the adhesin. Interestingly, considerable intraepithelial heterogeneity was revealed as the O75X adhesin bound to epithelium of the ureter but not to that of the kidney, bladder or urethra. The purified O75X adhesin bound specifically to laminin, a basement membrane glycoprotein, immobilized on nitrocellulose or polystyrene, suggesting that laminin is involved in the binding of the O75X adhesin to basement membranes.

Adhesins, Escherichia coli↗
PubMed1987

Plasminogen activators during differentiation of the human kidney.

Tissue-type plasminogen-activator antigenicity was immunohistochemically localized in the developing glomerulus of human embryonic kidneys using antibodies raised against a highly purified HeLa-cell activator [43]. At the very beginning of the S-shaped-body stage of glomerular differentiation, tissue-type activator antigenicity seemed to be co-distributed with a marker of invading endothelial cells, i.e., Ulex europaeus lectin. However, during further stages of glomerular remodelling and maturation, this plasminogen activator was also localized around developing and proliferating visceral epithelial cells (podocytes). Antibodies against the urokinase-type plasminogen activator did not react with any elements of developing glomeruli; rather, they stained the proximal tubules in more mature parts of the kidney, as revealed by double immunostaining using antibodies against the brush border. The present results suggest that the tissue-type plasminogen activator plays a role in the differentiation of glomerular structures during nephron morphogenesis.

Cell Differentiation↗
PubMed1987

Three distinct cell populations in rat kidney collecting duct.

The morphologically heterogeneous cell populations in the collecting ducts of the rat kidney were studied using immunocytochemical detection of Na+-K+-ATPase and the anion channel (band 3) glycoprotein. Both enzymes were localized to the basal aspect of separate and morphologically distinct subpopulations of cells in various segments of the collecting duct. Na+-K+-ATPase appeared to be present exclusively in principal cells as identified by their morphology, whereas band 3 antibodies reacted only with intercalated cells. However, 5-20% of cells with the morphological characteristics of intercalated cells failed to react with either antisera in various segments of collecting ducts. As band 3 glycoprotein serves in exchanging intracellular bicarbonate for chloride, it is highly likely that the cells positive for this antigen secrete protons. The method introduced here appears thus useful for distinguishing between principal and intercalated cells by differences in their enzyme content and further for revealing two subpopulations of intercalated cells. This method promises to provide a useful approach for studying the principal and intercalated cell populations in various metabolic states.

Animals↗
PubMed1987

Glycosylation of developing human glomeruli: lectin binding sites during cell induction and maturation.

Expression of cellular glycoconjugates during differentiation of human fetal kidney was studied using fluorochrome-labeled lectins. Each lectin revealed a characteristic binding pattern during the phenotypic change of the nephrogenic mesenchyme and during distinct stages of nephron development. The uninduced mesenchymal cells were positive for Pisum sativum (PSA), Concanavalin A (ConA), Wistaria floribunda (WGA), and Ricinus communis (RCA-I) lectins. However, these lectins failed to react with the uninduced cells of the S-shaped bodies, whereas Maclura pomifera (MPA), Triticum vulgaris (WGA) and, after neuraminidase treatment, Arachis hypogaea (PNA) agglutinins bound intensely to the presumptive podocytes. During later stages of nephrogenesis, MPA positively on the podocytes weakened and could not be observed in adult kidney glomeruli. Binding sites for Helix pomatia (HPA) agglutinin in glomeruli were also expressed only transiently during nephrogenesis. During further development PSA, ConA, WFA, and RCA-I reacted with mesangial cells in addition to the glomerular basement membranes. The segment-specific lectin binding patterns of the tubuli emerged in parallel with the appearance of brush border and Tamm-Horsfall antigens of the proximal and distal tubuli. The results show that nephron site-specific saccharides appear in a developmentally regulated manner and in parallel with morphologic maturation of the nephron. Lectins therefore appear to be useful tools for study of induction and maturation of various nephron cell types.

Binding Sites↗
PubMed1987

Ontogeny of cell type-specific enzyme reactivities in kidney collecting ducts.

Highly specific antibodies against vital enzymes of the collecting ducts were used to study the appearance of cell type specific enzyme profiles in developing rat kidneys. (Na+K)-ATPase, the abundant enzyme of principal cells, could be detected early in utero in most collecting duct cells. However, the characteristic basolateral polarization of this enzyme did not appear until the first hours after birth. After this, the relative amount of (Na+K)-ATPase immunoreactive cells along collecting ducts decreased steadily, to reach the amount found in adult rat kidneys by the 30th postnatal day. Carbonic anhydrase immunoreactivity characteristic for intercalated cells was not detectable in fetal kidneys, but appeared soon after birth, with steadily increasing numbers of cells that were positive. Interestingly, immunoreactive band 3 glycoprotein (anion channel protein of erythrocytes) did not appear until the 5th day of life, with only a slowly increasing number of cells positive for this probe. These results, showing the sequential appearance of cell type-specific enzyme reactivities along collecting ducts, likely reflect a similar pattern of functional development of the respective main cell types. These results may provide an explanation for physiologic neonatal acidosis, as the enzyme profile associated with proton secretion was seen to appear slowly during the first weeks of life in a distinct manner.

Animals↗
PubMed1987

Immunocytochemical characterization of carbonic anhydrase-rich cells in the rat kidney collecting duct.

Immunocytochemical detection of carbonic anhydrase (CA II), (Na+-K+)-ATPase and the anion channel (band 3) glycoprotein was used to study structural and functional heterogeneity of cells lining the collecting ducts, especially of intercalated cells, in the rat kidney. High content of CA II was found in intercalated cells as determined by morphology, although a weak diffuse cytoplasmic staining of this enzyme could be observed also in a subpopulation of principal cells. (Na+-K+)-ATPase could be detected exclusively in principal cells, whereas basolateral band 3 immunoreactivity was seen only in a subpopulation of intercalated cells. Double immunostaining experiments revealed that the weak cytoplasmic type of CA II and basolateral (Na+-K+)-ATPase immunoreactivities were colocalized in 20 to 30% (depending on the segment studied) of the collecting duct epithelial cells but, in contrast, cells rich in CA II or those with basal band 3 immunoreactivity seldom contained (Na+-K+)-ATPase. Instead, band 3 glycoprotein and the abundant CA II were colocalized in 20 to 35% of the cells in various segments of collecting ducts, whereas, band 3 and weak cytoplasmic CA II were seldom seen in the same cells. The results show that the current approach is useful for identifying and characterizing two distinct subpopulations of intercalated cells, both rich in CA II but differing in respect to the presence or absence of band 3 glycoprotein. On the basis of physiologic and biochemical data of the functions of these transport proteins we propose that the subpopulations of intercalated cells thus identified represent the acidifying and alkalinizing subtypes, respectively.

Animals↗
PubMed1987

Interstitial mononuclear cell infiltration in Heymann nephritis.

Interstitial mononuclear cell infiltration in rats during the development of autoimmune Heymann nephritis (HN) was studied using the fine-needle aspiration biopsy (FNAB) technique. The results were compared with those obtained by immunohistochemical studies of infiltrating T helper (T-h) and T suppressor/cytotoxic (T-s) cells, and with traditional histopathological and immunofluorescence examinations. Three weeks after initial immunization with isolated tubular brush border antigen, when the histopathological finding was quite normal, FNAB revealed increased numbers of interstitial blast cells, large granular lymphocytes and activated lymphocytes. These increases reached significant levels 2 weeks after a booster injection and were still prominent in a few rats with manifest membranous glomerulonephritis (MGN) and proteinuria 14 weeks after initial immunization. Immunohistochemical staining 3 weeks after immunization showed a significant increase in T-h cells in peritubular regions. Infiltration decreased successively 2 weeks after the booster and during manifest MGN. On the other hand, the mean number of cortically infiltrating T-s cells successively increased during the course of the study and this increase had reached a statistically significant level 2 weeks after the booster. Prominent T-s infiltration appeared in a few rats 2 weeks after the booster and when MGN was histopathologically manifest, and it was then associated with histopathologically detectable interstitial mononuclear infiltration and also with blast cell infiltration in FNAB. Our results suggest linkage between tubulointerstitial lesions in HN and cell-mediated immunoreactivity, and that severe interstitial inflammation is associated with T-s cell infiltration. Cytological interpretation indicated that infiltrating blast cells were plasmablasts, which may imply local antibody production, especially since anti-brush border antibody titres and blast cell infiltration simultaneously reached maximum levels 2 weeks after the booster.

Animals↗
PubMed1986

Location of adhesion sites for P-fimbriated and for 075X-positive Escherichia coli in the human kidney.

High-affinity binding sites for P-fimbriated and for 075X-positive Escherichia coli were located in the human kidney. Frozen sections of normal human kidney were double-stained first with fluorochrome-labelled bacteria and then with fluorochrome-labelled nephron site-specific lectins or antibodies. The P-fimbriate recombinant E. coli strain used showed specific adherence to glomerular structures, to the lumen of proximal and sital tubules and to vascular endothelium but did not adhere to collecting ducts or to peritubular sites. Two E. coli strains having the 075X adhesin showed specific adherence to renal interstitium, to glomerular elements and to Bowman's capsule. The method described allows the detailed determination of tissue-substructure specificity of bacterial adhesion. Our results demonstrate tissue tropism in the adhesion of E. coli to human kidneys and suggest a pathogenetic role for X adhesins.

Bacterial Adhesion↗