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Biomedical subjects

K Weber

Publications and source records attributed to K Weber.

At least 541 records · Page 30Linked to original sources
PubMed1982

Golgi detection in mitotic and interphase cells by antibodies to secreted galactosyltransferase.

Secreted galactosyltransferase from bovine milk was used to induce antibodies cross-reacting with corresponding intracellular enzymes in a variety of cell lines and tissues. In contrast to the original antigen, the reactive intracellular galactosyltransferase appears as individual species (apparent MW approx. 42000-46000) in SDS-polyacrylamide gel electrophoresis. In indirect immunofluorescence microscopy affinity-purified IgGs locate the galactosyltransferase in a distinct perinuclear and juxtanuclear position indicative for the Golgi region. The rearrangement of labelled structures upon colcemid or monensin treatment--drugs known to influence Golgi morphology and function--is further proof for a Golgi association. The fate and distribution of Golgi elements during mitosis is described at the light microscopical level using galactosyltransferase as easily identifiable marker. In addition we evaluate the utilization of wheat germ agglutinin (WGA) binding for Golgi identification on tissue culture cells and show that WGA is not a reliable marker for certain cell types such as MDCK.

Animals↗
PubMed1982

Proteinchemical characterization of three structurally distinct domains along the protofilament unit of desmin 10 nm filaments.

Limited chymotryptic cleavage of soluble chicken gizzard desmin protofilaments allows the characterization of three structurally distinct domains. A surface-exposed very basic amino-terminal region (the headpiece) with an amino acid sequence excluding alpha-helical organization (7.5 kd) is separated from the perhaps globular carboxy-terminal 48 residues (the tailpiece) by a distinctly different middle domain of approximately 330 residues. This 38 kd domain is very rich in alpha-helix (at least 83%), and electron microscopy reveals a thin rod with a length of 500 +/- 50 A. Amino acid sequence data also show that the rod domain is interrupted by a nonhelical portion. An alpha-helical array is able to form a coiled-coil spanning the carboxy-terminal half of the 38 kd domain. The alpha-type diffraction pattern of 10 nm filaments arises from a coiled-coil conformation displayed through most but not all of the middle domain of the protofilaments.

Amino Acid Sequence↗
PubMed1982

An F-actin- and calmodulin-binding protein from isolated intestinal brush borders has a morphology related to spectrin.

A high molecular weight protein from the brush border of chicken intestinal epithelial cells has been purified. This protein (TW 260/240), a complex of two polypeptides with apparent molecular weights of 260,000 and 240,000, accounts for a significant amount of the terminal web organization. TW 260/240 is an F-actin-binding protein that also interacts with calmodulin. Rotary shadowing reveals long flexible rods of double-stranded morphology tightly connected at each end. TW 260/240 is quite distinct from smooth muscle filamin and macrophage actin-binding protein (APB), but, in spite of its higher contour length (265 nm), seems to be related to erythrocyte spectrin (194 nm for the tetramer). Immunofluorescence microscopy with antibodies against TW 260/240 indicates the existence of a submembranous organization distinctly different from that of stress fibers. We have compared TW 260/240 with fodrin, a brain protein known to occur in submembranous organization but not previously characterized in molecular terms. TW 260/240 and fodrin are clearly distinct molecules but are similar in many aspects. Ultrastructural, biochemical and immunological results indicate three distinct classes of rod-like high molecular weight actin-binding proteins, possibly reflected by the prototypes filamin (ABP), spectrin and TW 260/240 (fodrin). The latter group may be responsible for calmodulin control of submembranous microfilament structures in various nonmuscle cells.

Actins↗
PubMed1982

Immunohistochemical localization of several cytoskeletal proteins in inner ear sensory and supporting cells.

Several structural and contractile proteins have been searched for with immunohistochemical methods using antibodies directed against these proteins. Three types of preparations from the guinea pig have been used: isolated stereocilia from the utricle, organ of Corti fragments obtained by cellular dissociation and 0.2-1 micrometer sections obtained by cryoultramicrotomy. The main finding is that different sets of proteins compose the cytoskeleton in supporting cells and the mechanoreceptor structures of the sensory cells. Thus, actin was found in association with fimbrin in the mechanoreceptive region of hair cells, whereas supporting cells, although rich in actin, did not reveal fimbrin. Instead tubulin was seen together with actin in supporting cells which also exhibited prekeratin. Fimbrin appears to function as a protein capable of making bundles and networks from actin filaments. Its exclusive presence in the mechanosensitive region of the sensory cells is possibly related to the function of these cells as mechanoreceptors.

Actins↗
PubMed1982

Expression of intermediate filaments in different human epithelial and mesenchymal tumors.

Fifty primary gastrointestinal and breast carcinomas, four embryonal rhabdomyosarcomas, six nonmuscular mesenchymal malignant tumors and one mesothelioma have been studied to determine what type of intermediate filaments they express, using affinity purified antibodies to prekeratin, vimentin and desmin and FITC or peroxidase labeled second antibodies. The tissues were alcohol fixed and paraffin embedded before use. In all carcinoma cases the tumor cells are stained by antibodies to prekeratin, while the vimentin antibody only decorates the stroma. Prekeratin positive tumor cells are not only seen in well differentiated tumors, but also in signet ring cell carcinomas. In the case of rhabdomyosarcoma the tumor cells clearly were decorated by antibodies to desmin, while the vimentin antibody only stained very few tumor cells. In cases of nonmuscular mesenchymal tumors, the tumor cells could only be labeled by antibodies to vimentin and not by antibodies to prekeratin or desmin. In biphasic tumors like mesothelioma, different parts of the tumor were separated by antibodies to prekeratin and vimentin.

Adenocarcinoma, Mucinous↗
PubMed1982

The expression of different intermediate-sized filaments in human salivary glands and their tumours.

The intermediate-sized filaments can be divided into several groups which are characteristic of different types of tissues (e.g.: epithelial, mesenchymal, muscle, astrocytic and neural origin). Antibodies specific for some of these filament types have been used to analyse a group of salivary gland tumours. Prekeratin-positive cells were seen in the normal gland, cystadenolymphomas, mucoepidermoid tumours, and squamous cell carcinomas which are all tumours of epithelial origin. The pleomorphic adenomas showed the presence of some cells which appeared to contain both prekeratin and vimentin. The results are discussed with respect to their histogenetic implications.

Adenoma↗
PubMed1982

Erythroid spectrin, brain fodrin, and intestinal brush border proteins (TW-260/240) are related molecules containing a common calmodulin-binding subunit bound to a variant cell type-specific subunit.

Spectrin, fodrin, and TW-260/240 form a group of structurally and functionally similar but not identical high molecular weight actin-binding proteins from chicken erythrocytes, brain tissue, or intestinal epithelial brush borders. Immunological data and one-dimensional peptide maps of the separated subunits suggest that a common (Mr 240,000) and a variant (Mr 220,000, 235,000, or 260,000) subunit account for the three different heterodimers. These results are in line with the related but distinct morphology of the three proteins observed in micrographs of rotary-shadowed molecules and the finding that the common (Mr 240,000) subunit seems to account for the calcium-dependent calmodulin-binding activity displayed by the three proteins. The possible functions of spectrin-like molecules in nonerythroid cells are discussed.

Animals↗
PubMed1982

Immunofluorescent localization of vimentin, prekeratin and actin during odontoblast and ameloblast differentiation.

The localization of constitutive proteins of different types of cytoskeletal components (prekeratin, vimentin, and actin) was examined in embryonic mouse molars using specific antibodies and immunofluorescence microscopy on frozen sections. Prekeratin and actin were found in the enamel organ. Preameloblasts demonstrated uniform staining, whereas ameloblasts demonstrated an apical accumulation of both prekeratin and actin. Vimentin and actin were observed in the dental papilla. A redistribution of vimentin accompanied the polarization of odontoblasts. A possible transmembranous control of cytoskeletal activities by the extracellular matrix is discussed.

Actins↗
PubMed1982

In vitro differentiation of mouse teratocarcinoma cells monitored by intermediate filament expression.

Teratocarcinoma differentiation has been studied using sera specific for each of the five intermediate filament (IF) classes. These antibodies distinguish cells of epithelial, muscle, neural, astrocytic, and mesenchymal origin. In embryoid bodies, derived from embryo transplants and obtained in the ascitic fluid by transplantation of teratocarcinoma, the cells of the inner cellular mass did not express any of these intermediate filament types while the outer cells expressed cytokeratin. Intermediate filament expression in the embryoid body thus appears analogous to that in the blastocyst and differs from that in embryonal carcinoma (EC) lines. Twelve EC lines have now been shown to express vimentin although in some EC lines not all cells express vimentin. Other established permanent differentiated cell lines, derived from EC lines in vitro or from tumors in vivo, have been characterized with respect to the type of IF they contain. The distribution of different IF types has been examined in EC cells induced to differentiate by addition of retinoic acid. The proportion of cells expressing each type of intermediate filament appears to depend on the EC cell line used, on the inducing agent, and on the length of treatment. Thus, for instance, F9 cells express cytokeratin, PCC3 derivatives express vimentin, many 1009 derivatives express either glial fibrillar acidic protein (GFA) or neurofilament proteins. Overall the results obtained are in excellent agreement with emerging principles of intermediate filament expression during embryonic differentiation, thus emphasizing the potential use of the various EC lines to study differentiation in culture.

Animals↗
PubMed1982

A phosphorylated basic vaccinia virion polypeptide of molecular weight 11,000 is exposed on the surface of mature particles and interacts with actin-containing cytoskeletal elements.

A phosphorylated vaccinia virus structural polypeptide of an apparent molecular weight of 11,000 (p11K) was isolated by preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis and used for antibody induction. After purification by antigen affinity chromatography, the immunoglobulins detected only one target of a rather basic nature in two-dimensional immune blotting procedures of total virion proteins. By use of a combination of biological, biochemical, and microscopic techniques, p11K could be located on the surface of those vaccinia virus particles, with "classical" morphology and a buoyant density of 1.27 g/cm3. Upon immunoprecipitation from radioactively labeled infected cells, p11K appeared to be complexed to two additional virus structural proteins, which could be tentatively identified by their molecular weights as precursors for the two major core constituents. When virus assembly was inhibited by rifampin treatment of infected cells, a great part of p11K, either free or in complexed form, was found associated with actin-containing cytoskeletal elements. The ability of p11K to interact with a not-yet-identified, microfilament-associated cellular protein may be related to previous findings showing that assembled vaccinia particles in situ are found in connection with microfilaments. A possible role for the structures precipitated by p11K-specific antibodies in early stages of particle assembly is discussed.

Animals↗
PubMed1982

Antibodies to intermediate filaments as diagnostic tools: human gastrointestinal carcinomas express prekeratin.

Twenty-five primary gastrointestinal carcinomas have been studied using immunofluorescence microscopy with affinity-purified antibodies to prekeratin and to vimentin. The tissues were alcohol fixed and paraffin embedded before use. In all cases (i.e., one case of esophagal carcinoma, seven stomach carcinomas, and 17 large bowel carcinomas) the tumor cells are stained by antibodies to prekeratin. In cases in which only very few tumor cells are present, such as signet ring carcinoma, immunofluorescence with prekeratin antibody provides an easy way to visualize single tumor cells. When the same specimens were tested with antibodies to vimentin, the tumor cells were unstained, and only the fibroblasts and vessels of the stroma were decorated. Four of the tumors were also negative when tested with antibodies specific for either desmin, or glial fibrillary acidic protein or neurofilaments. Three metastases to the abdominal region from tumors originating in the ovary, stomach, and large bowel were like the primary tumors in that the tumor cells were positive when stained with antibodies to prekeratin and negative when tested with the antibodies to vimentin.

Adenocarcinoma↗
PubMed1982

[Adenine nucleotides and metabolites of glycolysis in the liver in auxiliary transplantation].

The metabolic state of the liver during preservation as well as in and after auxiliary transplantation was investigated in dogs. The biopsy was carried out by means of TRU-CUT biopsy needle. - The ATP concentration, the storage of energy, the amount of the adenine nucleotides, and the ATP/ADP quotient decrease in the preserved liver. The AMP concentration, the concentration of the hexosemonophosphates and the mass-effective quotient of the phosphofructokinase increase simultaneously. The energy supply is the glycolysis exclusively. A lactate accumulation is avoided by continuous perfusion. - The changeover of the anaerobic to the aerobic energy preparation took place by degrees after the recovery of the liver circulation. The ATP concentration, the ATP/ADP quotient, the storage of energy, and the amount of the adenine nucleotides increase in the transplanted liver. - An irreversible ischemic damage of the liver appears in the metabolic state of the organ by a massive decrease of the ATP concentration below 0.7 mmol/kg, the amount of the adenine nucleotides below 1.8 mmol/kg, and AMP concentration.

Adenine Nucleotides↗