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Biomedical subjects

H Winter

Publications and source records attributed to H Winter.

At least 181 records · Page 10Linked to original sources
PubMed1984

Differential expression of intermediate filament proteins in two rat ascites hepatoma lines of common origin.

Two rat ascites hepatoma lines, AH130, originating from a azodye-induced liver carcinoma, and AH130F(N), spontaneously derived from the AH130 line during serial i.p. transplantation were analyzed for their intermediate filament protein expression by one and two-dimensional gel electrophoresis, in vitro translation of their mRNAs and immunolocalization using antisera against distinct subunits and compared with intermediate filament expression of normal hepatocytes. Normal rat hepatocytes synthesize mainly two keratin subunits at 55 and 47 kDa. The AH130 hepatoma line maintains the expression of these proteins, however, in addition also synthesizes a 40-kDa keratin subunit and large amounts of vimentin. In contrast, the AH130F(N) hepatoma line has lost the ability to express keratin subunits; its intermediate-sized filament compound is apparently built up only by vimentin. Even by means of the sensitive immunoblotting technique using antisera against the normal hepatocyte keratin subunits, no keratin synthesis can be demonstrated in this line. The marked differences in the metastatic capacity of the two hepatoma lines make them promising tools to investigate a possible involvement of intermediate-sized filament expression in the process of tumor spreading.

Animals↗
PubMed1984

The keratin polypeptide patterns in heterotypically recombined epithelia of skin and mucosa of adult mouse.

Epithelial-mesenchymal interactions were investigated considering both morphologic criteria and keratin polypeptide expression in homotypic and heterotypic recombinants of adult mouse skin and oral mucosa. Two series of cross-recombinants of epithelia with different morphology and keratin patterns were chosen: (a) footpad epidermis/ear dermis and ear epidermis/footpad dermis; (b) palate epithelium/cheek connective tissue and cheek epithelium/palate connective tissue. Homotypic and heterotypic recombinants were prepared after EDTA-separation of the original tissues and then grown on syngeneic mice in subcutaneously prepared protected graft chambers. EDTA-separation is especially suited to completely separate the epidermal-dermal union, and the transplantation procedure used strictly prevents contamination with host epithelium. Five weeks after implantation keratins were analyzed by one and two-dimensional gel electrophoresis and peptide mapping. In both series, homotypic recombination of the tissues did not alter the original morphology and keratin polypeptide composition of the individual epithelial components. Ear epidermis displayed no significant changes in structure or keratin pattern in heterotypic recombinants. Recombined with ear dermis, footpad epidermis showed acquisition of some morphologic features typical for ear epidermis and slight changes in keratin composition which were, however, difficult to interpret due to the normal similarities of footpad keratin with that of ear. In contrast, the heterorecombinants of the palate/cheek series exhibited considerable alterations in their keratin patterns. Either epithelium showed suppression of distinct keratin subunits and de novo expression of subunits characteristic of the epithelium normally associated with the connective tissue component. The keratin patterns of both matches closely resembled each other and represented patterns intermediate between the normal patterns. This partial, however, significant modulation in the expression of differentiation markers was paralleled by similarly directed changes in the architecture of the heterotransplanted tissues, thus indicating that both morphogenesis and cytodifferentiation of certain adult epithelia can be influenced by extrinsic mesenchymal factors.

Animals↗
PubMed1984

Karyotyping, red blood cell and haemoglobin typing of the mithun (Bos frontalis), its wild ancestor and its hybrids.

In Bhutan in remote parts of the Himalayas the mithun (Bos frontalis) has been used probably for centuries in an ingenious system for crossbreeding with domestic cattle which results in highly profitable hybrid females. The hybrid males are infertile and so far no stable crossbreed has been developed. Genetic analyses reported in this paper support the view that the gaur is the wild ancestor of the mithun. Both have only 58 chromosomes in contrast to 60 in cattle and also different, hitherto undescribed haemoglobins and blood groups which would justify the revision of the present classification of the subfamily Bovinae. If, with the aid of modern genetic methods, a stable crossbreed could be developed, dairy and beef production in Bhutan and many climatically similar areas could benefit greatly. Because of its remarkable size the mithun may, in the hands of enterprising breeders, also make a useful genetic contribution to beef production elsewhere.

Animals↗
PubMed1984

Differential expression of intermediate-filament proteins in murine sarcoma 180 ascites or solid tumor.

The intermediate-filament proteins in Sarcoma 180 ascites cells and solid tumors generated by s.c. injection of ascites cells in NMRI or nude mice were analyzed by one- and two-dimensional gel electrophoresis and identified by immunological methods. The ascites form of Sarcoma 180 coexpresses keratin and vimentin, whereas the solid tumor ceases to synthesize keratins but continues to express vimentin. These reversible changes in the expression of intermediate-filament proteins may be due to a change in the differentiation program induced by environmental conditions like growth with or without cell contact.

Animals↗
PubMed1983

Keratin biosynthesis in normal mouse epithelia and in squamous cell carcinomas. mRNA-dependent alterations of the primary structure of distinct keratin subunits in tumors.

The keratin polypeptide patterns of two murine transplantable squamous cell carcinomas--originally induced by chemical means in the back skin and in the forestomach epithelium--are deficient in high molecular weight keratin subunits (greater than 60 kDa) invariably present in the corresponding normal tissues. In addition, the keratin polypeptide composition within the low molecular weight range showed further alterations with regard to the corresponding keratin subset of normal tissues in that both tumors expressed a 40-kDa protein, and a 56-kDa protein was selectively found in the forestomach tumor. A comparison of the charge properties of normal and tumor keratin polypeptides revealed that the two uppermost tumor proteins at 60 and 58 kDa were basic in nature whereas their normal molecular weight counterparts belonged to the acidic subset of the pattern. These tumor proteins also showed mutually identical peptide maps which, however, were considerably different from those of the normal proteins. The remaining tumor keratin subunits at 52, 50, 48, and 45 kDa, common also to the normal tissues, had retained their normal charge properties. In vitro translation of mRNA, isolated from both normal and tumor tissue, revealed that every tumor keratin polypeptide is encoded by its own mRNA. In contrast to normal keratinizing tissues, there is therefore no indication of post-translational protein processing in tumors. The in vitro translation products of tumor RNAs had all properties in common with the in vivo tumor proteins, thus indicating that every deviation of the tumor keratin spectrum from the normal state is determined at the mRNA level.

Animals↗
PubMed1983

Keratin polypeptide composition as a biochemical tool for the discrimination of benign and malignant epithelial lesions in man.

An investigation was undertaken of the keratin polypeptides of various benign and malignant tumors of the human skin and vaginal epithelium by one and two dimensional gel electrophoresis. The keratin patterns of benign tumors were found to be similar to the patterns of normal epithelium or stratum corneum. The relative proportion of stratum-corneum associated keratin polypeptides to those polypeptides characteristic for the living layers corresponds to morphological features (e.g., hyperkeratosis, acanthosis). In contrast to benign tumors, epithelial carcinomas totally lack the group of high-molecular-weight keratins. This finding may be helpful in the diagnostic discrimination between benign and malignant epithelial lesions.

Electrophoresis↗
PubMed1983

Keratin synthesis in normal mouse epithelia and in squamous cell carcinomas: evidence in tumors for masked mRNA species coding for high molecular weight keratin polypeptides.

Transplantable mouse squamous cell carcinomas (SCC), originally derived either from back skin or forestomach epithelium, do not synthesize high molecular weight keratin polypeptides [greater than 60 kilodaltons (kDa)] involved in the process of terminal differentiation in the corresponding normal tissues. The in vivo tumor keratin spectra consist of only low molecular weight keratin subunits at 60, 58, 52, 50, 47, and 46 kDa, each encoded by its own mRNA and encountered also in normal epidermis and forestomach epithelium. In addition, both tumors express a mRNA-dependent 40-kDa protein, whereas a 56-kDa protein and its mRNA are selectively found only in the forestomach tumor. Translation of mRNAs from both tumors in a cell-free system does not only generate analogues of the in vivo tumor keratin polypeptides, but also both SCC possess an additional mRNA coding in vitro for a 67-kDa keratin subunit that is not expressed, however, in the carcinomas in vivo. The identity of this in vitro synthesized keratin member with a 67-kDa keratin polypeptide of both normal epidermis and forestomach epithelium was confirmed by comparison of charge properties and peptide mapping. With regard to this particular keratin polypeptide, the tumors are obviously able to sequester the polypeptide's mRNA in an untranslatable state in the cells.

Animals↗
PubMed1983

[Special tactical procedure in the surgery of monstrous Spiegler tumors].

A 54-year-old patient with generalized Spiegler tumors is presented. Monstrous tumors on the head and back and the risk of infection required a particular surgical technique. After excision of the tumor areas, optimal wound conditions for transplantation were obtained by pretreatment with a newly developed synthetic foam. This was followed by a mesh-graft technique which produces especially excellent functional and aesthetic results.

Carcinoma, Adenoid Cystic↗
PubMed1983

[Electron microscopy study of insufficient great saphenous veins].

Results of electron microscopic investigations of the vena saphena magna in varicosis are reported. The proximal and distal portion were used in each case. There were neither unambiguous ultrastructural differences on the endothelial cells nor a distinctly different number of Weibel-Palade bodies within the endothelial cells. Compared to this, a more massive dysplasia of the media was ascertained in the distal portion than in the proximal one. It is possible that this represents the structural equivalent of a different pathophysiological reaction which is expressed ultrastructurally in form of vacuolic cytoplasm and disintegration of myofilaments.

Cytoskeleton↗
PubMed1982

Keratin polypeptide analysis in fetal and in terminally differentiating newborn mouse epidermis.

The keratin polypeptide pattern of neonatal mouse epidermis consists of eight individual polypeptides having molecular weights of between 46,000 and 67,000. Unlike the keratin patterns in adult mouse epidermis, this pattern is not subjects to body site-specific alterations regarding the specific content of distinct polypeptides or the absolute number of keratin constituents. At day 16 of fetal development the neonatal keratin pattern is only partially expressed, it being fully completed just prior to birth at day 19 of gestation. A comparative analysis of the sequential changes in epidermal morphology and keratin pattern during the last third of embryonic development confirms the view that, independent of the species, keratin polypeptides below 60,000 mol. wt. are generated by basal cells, whereas the biosynthesis of high molecular weight keratin members take place in the suprabasal cell compartments of keratinizing epithelia. The site of origin of five polypeptides (60,000, 58,000, 52,000, 49,000, 46,000) could therefore be attributed to the basal cell layer, the remaining three polypeptides (67,000, 64,000, 62,000) being synthesized in the outer metabolically active epidermal layers. Similar conclusions could be drawn after subfractionation of neonatal epidermis into living (basal, spinous, and granular) and dead cell layers (stratum corneum), and investigation of the corresponding keratin patterns. During their progression through the epidermis, two proteins (60,000, 58,000) undergo a hitherto undescribed type of posttranslational modification characterized by a slight increase in size and a change in electrical charge. The mechanism underlying this modification is unknown and it is unclear whether the modification if functional or trivial. The largest keratin polypeptide (67,000) of the protein family -- probably a product of spinous cells -- disappears from the cornified layer without any evidence that it serves as a precursor for smaller keratin subunits.

Animals↗
PubMed1981

Poly(A)- and oligo(A)-adjacent sequences in RNA from the large hnRNP complexes of rat liver.

The present report describes the isolation of hnRNP complexes with sedimentation coefficients greater than 80 S from rat liver nuclei without the use of ribonuclease inhibitors. The RNA moiety from these complexes is heterogeneous in size, with a mean sedimentation coefficient of 16 S when assayed with polyacrylamide-formamide gel electrophoresis. About 3% of this RNA binds to oligo(dT)-cellulose, the size of the bound fraction being somewhat smaller than the bulk of the hnRNP-RNA. This poly(A) RNA contains two adenylate tracts, one with about 30 and the second with about 200 adenylate residues. Reverse transcription of the poly(A)-containing RNA and hybridization of the cDNA with their respective templates shows two well-defined frequency populations, the first one separated from the second by almost 2.5 logs in the R0t curve. The same distribution was found, whether the hybrids were analysed with S1 nuclease or hydroxyapatite. Both separated frequency classes hybridize to total genomic DNA, the abundant one at C0t values typical for repetitive and unique sequences, the scarce one only at C0t values typical for unique sequences. The two populations are also able to hybridize with polysomal polyadenylated mRNA, the dilution of both frequencies being very similar in the cytoplasm.

Adenine Nucleotides↗
PubMed1981

A cooling chain for studies of cryofixed biological specimens by scanning transmission electron microscopy and X-ray microanalysis.

A cooling chain is described which enables the transfer of frozen hydrated biological specimens (ultrathin cryosections as well as about 1 micrometer thick cultured cells) from a cryoultramicrotome into a scanning transmission electron microscope with a field emission gun. Transfer is done at 118 K, specimen temperature in the microscope is 165 K. Sublimation processes are controlled visually and by mass spectrometry. Electron micrographs and X-ray microanalytical spectra of cryofixed unstained tissue culture cells and rat liver tissue sections are described and discussed. Contamination of the specimen is much reduced by use of the cold stage.

Animals↗
PubMed1981

Carcinoma-specific keratin polypeptide patterns in keratinizing epithelia of rodents : independence of species- and tissue-specific variations.

A comparative investigation of the one- and two-dimensional electrophoretic keratin polypeptide patterns of various keratinizing epithelial tissues and of benign and malignant tumors of these tissues in the rodent species mouse, rat and hamster was undertaken. Keratin polypeptides of all normal epithelia investigated (vaginal, anal and forestomach epithelium) appear in a molecular weight range of about 40 K--70 K daltons and can be divided according to molecular weight and electrical charge into three groups. The large keratins (group A) have a basic character, while the lower molecular weight components of groups B and C are acidic in nature. The tissue-specific variations within one species are minimal and, apart from minor quantitative differences, mainly concern differing numbers of components within groups A and B, whereas the species-specific variations are more pronounced and apply to all three groups of keratins, which show a variable number of individual polypeptides differing in molecular weights and/or electrical charge. Independent of the tissue- and species-specific differences, keratins of epithelial carcinomas exhibit a special pattern differing from that of their corresponding intact tissues, as well as from benign tumors, by the lact of the large keratin polypeptides of group A. These characteristic differences in the keratin polypeptide composition of normal epithelia and of benign and malignant tumors may be useful for the diagnosis of epithelial tumors.

Animals↗
PubMed1980

Albumin messenger RNA after partial hepatectomy and sham operation.

Albumin mRNA was quantified in nuclear RNA and in polysomal and post-polysomal poly(A)-containing RNA from untreated, hepatectomized and laparotomized rat livers. A prominent reduction of albumin-specific RNA sequences was observed in all subcellular fractions 50 h after partial hepatectomy, compared to both untreated and sham-operated livers. Surprisingly, laparotomy itself also induced a dilution of albumin-specific sequences at earlier times after operation in nuclei and in post-polysomal supernatant, but not in polysomes.

Albumins↗