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Biomedical subjects

B Voss

Publications and source records attributed to B Voss.

At least 55 records · Page 3Linked to original sources

p53 accumulation in polynuclear-giant-cells.

Accumulation of p53 has been reported in nearly all malignant human tumours. Macrophage derived giant cells of sarcoid granulomas in human lung tissue also show intense staining for p53 while normal alveolar macrophages remain unstained. Since sarcoid giant cells are not considered to be either pre-neoplastic nor to exhibit p53 gene mutations, two different physiological functions of p53 may be illustrated. Alveolar macrophages were isolated from rat lungs and cultured in vitro. Accumulation of p53 was observed by indirect immunohistochemistry after application of polyclonal rabbit serum directed against murine p53 (CM5). Antiproliferating cell nuclear antigen (PCNA) antibodies were used to study DNA synthesis. Most of the multinucleated giant cells derived from macrophages accumulated p53 in the cytoplasm, while only few nuclei were stained. PCNA was found in most giant cells nuclei. However, PCNA positivity was visible in few mononucleated macrophages. Isolated alveolar macrophages in vitro clearly divide and since nuclear division is a late event in the cell cycle, p53 may be involved in G1/S-control and in other cell-cycle-checkpoints between mitosis and cytokinesis.

Animals↗

Detection of transforming growth factor beta 1 mRNA in cerebrospinal fluid cells of patients with meningitis by non-radioactive in situ hybridization.

Meningitis is a serious disease mostly caused by viral or bacterial infections. In complicated cases it may lead to brain damage and death. The infection and cell damage result in a cellular and immunological response. Following this, a high secretion of cytokines can be expected. Cytokines, especially tumour necrosis factor alpha (TNF-alpha) and interleukin-1 (IL-1), promote the inflammatory reactions in the subarachnoid space. Transforming growth factor beta 1 (TGF-beta 1) has antagonistic effects on TNF-alpha and IL-1-mediated processes. Therefore, it suppresses inflammatory reactions. To observe the expression of TGF-beta 1 in transcellular signalling in the inflammatory processes of meningitis, we investigated TGF-beta 1 mRNA in cells in the cerebrospinal fluid of three patients with meningitis by non-radioactive in situ hybridization. All patients fulfilled the usual clinical criteria of meningitis. In one case Neisseria menigitidis could be identified as the pathogenic agent. In the remainder, no agent could be isolated. In all cytological preparations of the cerebrospinal fluid of these patients a high level of TGF-beta 1 mRNA was detectable in the cell populations. It was possible to distinguish between the different cell types of the cerebrospinal fluid and to attach the mRNA expression to them. On the one hand, this makes it possible to investigate pathogenesis and defence mechanisms in bacterial and aseptic meningitis on a cellular level; on the other hand, it may open new perspectives in the control of disease development, prognosis, diagnosis and supporting therapy.

Adult↗

Detection of MDM2-proto-oncogene in paraffin embedded human bronchial epithelium.

Recently a new proto-oncogene, the murine double-minute 2 (MDM2), has been described. MDM2 becomes oncogenic due to amplification and overexpression. Among other proto-oncogenes MDM2 becomes interesting since MDM2 protein can associate with both mutant and wild type p53 tumor suppressor gene products and thus inhibit p53-mediated transactivation of other genes. Loss of p53 tumor suppressor function is the most frequently observed alteration in human tumors. Immunohistochemical studies investigating the quantity of MDM2 protein in human sarcomas revealed an overexpression in 30% of the specimens. Here we describe the successful use of a monoclonal antibody (IF2) for the detection of MDM2 protein in paraffin-embedded tissue from human lung biopsies. 18 out of 44 specimens (41%), predominantly mucosal epithelial and glandular epithelial cells, stained positive for MDM2. No significant difference was observed between non-cancerogenic cells adjacent to tumor cells and those specimens without any tumor cells but altered by inflammatory processes. In general, the staining pattern was restricted not to the nuclei, but to selected subnuclear compartments, probably representing the golgi apparatus or the endoplasmatic reticulum. Our data support the hypothesis that in addition to its nuclear function of forming a complex with p53, MDM2 may also be secreted and thus have a transcellular effect.

Animals↗

Basement membrane proteins in synovial membrane: distribution in rheumatoid arthritis and synthesis by fibroblast-like cells.

Rheumatoid arthritis is a complex disease of unknown origin. In consequence of some immunological reactions, proliferative invading synovial tissue leads to destruction of normal joint architecture. The aim of this study was to investigate qualitative changes in extracellular matrix distribution of proliferating rheumatoid synovium and their cellular origin. Synovial tissues from 57 clinically indicated arthrotomies were investigated with immunofluorescence, using specific antibodies against extracellular matrix proteins in tissue slides and cultured cells, which were also studied for collagen biosynthesis. Results indicated that synovial fibroblast-like cells synthesize and secrete basement membrane proteins laminin and collagen type IV as e.g. endothelial cells or organogenic fibroblasts. Laminin and collagen type IV were specifically demonstrated pericellularly in the hyperplastic lining layer of active rheumatoid synovitis. These findings are discussed with respect to the possible implication of altered cell-matrix interactions in rheumatoid synovial proliferation.

Arthritis, Rheumatoid↗

[Collagens and growth factors in heterotopic ossification].

Heterotopic Ossification (HO) occurs as a consequence of several diseases and of various forms of trauma. HO is particularly frequent in paraplegic patients with spinal cord lesions. It is obvious that extraskeletal cells are able to differentiate into an osteogenic direction. However, the mechanisms of the induction process of HO and the stimulating agents are not precisely known. A novel tool for studying the ossification process at the level of transcription is the technique of non-radioactive in situ hybridisation. Using digoxigenin labeled cDNA probes we investigated the distribution patterns of types I, II and III collagen mRNAs and the mRNA of Transforming Growth Factor beta 1 (TGF-beta 1) in heterotopic ossification of pressure sores of paraplegic patients. The three collagen mRNAs as well as the TGF-beta 1 mRNA exhibited substantially divergent distribution patterns. Type I (alpha 1) collagen mRNA was predominantly detectable in preosteoblasts, chondroblasts and chondrocytes of the ossification zone. Type II (alpha 1) collagen mRNA was nearly exclusively found in cells of the chondrogenic lineage. Type III (alpha 1) collagen mRNA was detectable at low levels in soft tissue, but was strongly expressed by chondroblasts and chondrocytes of heterotopic cartilage. In contrast expression of TGF-beta 1 mRNA was found in a spatial different distribution pattern in areas of proliferation of mesenchymal tissue and in different stages of ectopic bone formation. As in the case of collagen Type I (alpha 1) and III (alpha 1) mRNAs the maximum of localization of TGF-beta 1 was detected in chondroblastic areas of heterotopic ossification. Taken together our in situ hybridization experiments provide evidence that chondrogenic cells play a central role in the process of HO with a phenotypic alteration in collagen type expression and a strong expression of TGF-beta 1 mRNA. These findings support individual in vivo function for TGF-beta 1 in local cellular regulation of ectopic bone formation.

Cartilage↗

[Oncogenes and tumor suppressor genes in the pathogenesis of lung tumors].

The recent results obtained from investigations based on molecular biological techniques have led to a better understanding of recurrent genetic causes important for the pathogenesis of tumors. Several genes have been identified as being involved in the development of cancer. In many cases, the activation of oncogenes or the inactivation of tumor-suppressor genes is the predominant reason for cancerogenic cell transformation. Functional dysregulation is frequently the consequence of mutations, resulting in an alteration of the primary structure of the DNA. As our understanding of the nature, function, and interaction of these genes evolves, new opportunities for early diagnosis, classification, prevention, and treatment of malignant tumors will arise. The present report summarizes the current molecular biological aspects of several oncogenes (erbB, ras, myc, raf, fos, jun, bcl, mdm2, myb, kit CSF1R, met) and tumor suppressor genes (p53, rb, mts) involved in lung-cancer development with respect to the pathology of lung tumors, including the importance of these genes as far as the clinical course of the disease is concerned.

Cell Transformation, Neoplastic↗

Localization of collagen types I, II, and III mRNAs in human heterotopic ossification by non-radioactive in situ hybridization.

Heterotopic ossification is a metabolically active process which shares several properties of orthotopic bone formation and, therefore, represents an excellent model for the investigation of matrix components. A novel tool for studying the ossifying process at the level of transcription is the technique of non-radioactive in situ hybridization. Using digoxigenin labeled cDNA probes we investigated the distribution patterns of types I, II and III collagen mRNAs in heterotopic ossification of pressure sores of paraplegic patients. The three collagen mRNAs exhibited substantially divergent distribution patterns. Type I (alpha 1) collagen mRNA was predominantly detectable in preosteoblasts, prechondroblasts and chondrocytes of the ossification zone. Type II (alpha 1) collagen mRNA was nearly exclusively found in cells of the chondrogenic lineage. Type III (alpha 1) collagen mRNA was detectable at low levels in soft tissue, but was strongly expressed by prechondroblasts and chondrocytes of heterotopic cartilage. Our in situ hybridization experiments provide evidence that chondrogenic cells in heterotopic ossification show a phenotypic alteration in collagen type expression. These results indicate that chondrocytes of heterotopic cartilage show a co-expression of types I (alpha 1), II (alpha 1) and III (alpha 1) collagen mRNAs.

Collagen↗

The perivascular connective matrix.

The functional properties of the perivascular matrix facilitate the movement, protection and the nutrition of the blood vessels. At the same time the matrix deliniates the vessels to the organs. Different vascular diseases of the vascular system implicate the perivascular matrix consisting of a network of structural and cellular connective tissue components. Impairment of its structural integrity predominantly occurs either from primary or secondary affections. Monospecific antibodies directed against different structural proteins enable detailed histomorphological examinations of the inflammatory tissue reaction in the perivascular space. Since myofibroblasts, fibrocytes, endothelial cells, and macrophages participate in tissue repair mechanisms, in vitro studies on the collagen synthesis may contribute to the understanding of the perivascular tissue reaction according to injury. The present report summarizes perivascular diseases and the in vitro synthesis of procollagen, collagen, and fibronectin of endothelial cells, fibroblasts, smooth muscle cells, and macrophages.

Animals↗

[Expression and secretion of alpha-2-macroglobulin by dust-stimulated alveolar macrophages].

In dust-induced, fibrosing lung processes macrophages are increased activated by foreign body reactions. The release of monokines and proteolytic enzymes, which depends on phagocytosis, may lead to destruction of the extracellular matrix with the consequence of degradation and restitution. Also the transcellular signaling or cell-matrix-interaction may finally result in development of fibrosis. However the proteolytic effect of elastase and collagenase can be inhibited by alpha-2-macroglobulin. Alpha-2-macroglobulin is a protease-inhibitor, which is synthesized by macrophages and has a wide spectrum of inhibitory abilities. Our interest was focused on observation of the production of alpha-2-macroglobulin by alveolar macrophages after stimulation with inorganic dusts of different chemical and physical properties. Rat alveolar macrophages were isolated by bronchoalveolar lavage and exposed to crocidolite, quarz or welder steam dust in vitro. The expression and secretion of alpha-2-macroglobulin was examined by non radioactive in situ hybridization, indirect immunofluorescence and radial immunodiffusion according to Mancini. The stimulated rat alveolar macrophages showed an increased expression of alpha-2-macroglobulin-mRNA and also an enhanced synthesis of alpha-2-macroglobulin-protein. Besides only small differences between the substances used for stimulation were demonstrated.

Animals↗

[Bronchopulmonary precancerous conditions and tumors--risk groups from the occupational medicine viewpoint].

Risk groups with regard to bronchopulmonary precancerous and tumor diseases of occupational origin can be deduced from current occupational disease statistics. Most prominent are those working with asbestos. Each year about 250 asbestos-associated bronchial carcinomas and 400 mesotheliomas are recognized and compensated; the tendency is increasing. Because of the long latency time, the frequency peak will probably be reached in about 15 years in spite of the prohibition of asbestos usage. The second place is probably taken by malignomas among the underground uranium mine workers in Thuringia and Saxony (SDAG Wismut). Next come bronchial carcinomas with silicosis (carcinoma in scar tissue) after exposure to chromium(VI) and arsenic compounds as well as various other chemicals and metals. Dose-activity relationships are significant for all occupational carcinogenic agents, as there are also often syncancerogenic influences (especially smoking). From the data on previous loading, high risk groups, for example, among the insulation workers exposed to asbestos or uranium miners in the so-called "wild years", can be defined. A suitable screening method for the detection of bronchopulmonary tumors in the early stages has not yet been established. Medical checkups for the respective risk groups concentrate on the early X-ray detection of circular foci. As shown by recent studies, cytological sputum diagnosis, (fluorescence) bronchoscopy, and BAL cytology must be employed much more frequently in the high risk groups so that the prognostically more favorable stages of preneoplasm and carcinoma in situ can be detected and possibly treated curatively. These procedures are currently reaching a considerably higher sensitivity with the help of modern molecular biology techniques (e.g. detection of tumor-associated genetic changes and gene products). This contributes to an improvement in surveillance examinations with increasing detection of the curable early forms of tumors. However, only the further development of primary prevention, i.e. the greatest possible minimization or, if possible, total elimination of contact with carcinogenic agents and the consequent control of occupational protection will lead to a drastic reduction in the occupational risk of cancer.

Carcinoma, Bronchogenic↗

SAP90, a rat presynaptic protein related to the product of the Drosophila tumor suppressor gene dlg-A.

A novel synapse-associated protein, SAP90, accumulates around the axon hillock of Purkinje cells in rat cerebellum. By immuno-electron microscopy, SAP90 has been localized to the presynaptic termini of basket cells forming inhibitory, gamma-aminobutyric acid (GABA)ergic synapses onto Purkinje cell axon hillocks. The amino acid sequence for SAP90 has been deduced from the nucleotide sequence of a series of overlapping cDNA clones. SAP90 is related to the gene product encoded by the Drosophila tumor suppressor gene dlg-A. SAP90 and the dlg-A product share an overall sequence identity of 54%. Three distinct domains can be identified: (i) a potential cytoskeletal region consisting of three repeats of 90 amino acids in length, (ii) a domain with similarity to SH3, a putative regulatory motif found in the src family of non-receptor protein tyrosine kinases and several proteins associated with the cortical cytoskeleton, and (iii) a carboxyl-terminal domain homologous to yeast guanylate kinase. These features suggest a possible role for SAP90 in a guanine nucleotide-mediated signal transduction pathway at a subset of GABAergic synapses in the rat cerebellum.

Amino Acid Sequence↗

Distribution of collagen types I, III, and IV in peptic ulcer and normal gastric mucosa in man.

The quality of peptic ulcer healing does not only mean complete epithelial restitution of the mucosal surface but also adequate repair of the underlying connective tissue. To obtain more information about the metabolism of extracellular matrix proteins in gastric mucosa and submucosa, we investigated biopsy specimens from six patients with antral peptic ulcers and six normal controls by staining of collagen types I, III, and IV with an immunofluorescence technique. In normal mucosa we found a certain amount of collagen types I and III in equal distribution and almost no collagen type IV. In contrast, there was a remarkable increase of collagen types I and III in peptic ulcers predominantly located at the ulcer edges. These results are compatible with the view that extracellular matrix proteins play some part in the ulcer healing process.

Collagen↗

[Pulmonary and pleural reaction patterns to artificial mineral fibers --rockwool].

Epidemiological and animal studies about the fibrogenic and carcinogenic properties of natural mineral fibers required the development of man made vitreous fibers as substitutes for asbestos containing material. The question about the possible fibrogenic and carcinogenic properties of man-made vitreous fibers is not yet answered. By means of different experimental animal studies we tried to investigate the man made vitreous fibers-related pulmonary and pleural diseases. The experimental administration of rockwool induce lesions in the lung of the rats. The lung showed an extensive granulomatous inflammation. In the observation time of 10 months we did not find any malignant tumor of the lung and the pleura.

Animals↗

VILIP, a cognate protein of the retinal calcium binding proteins visinin and recoverin, is expressed in the developing chicken brain.

Using a selective cloning approach we previously isolated a number of cDNAs of transcripts that are newly expressed during terminal differentiation of the chicken optic tectum. Here, we have characterized one of these cDNAs (OZ1) by Northern analysis and in situ hybridization. The OZ1 cDNA hybridizes to two transcripts of 1.6 kb and 2.9 kb which are widely expressed in the brain but not detectable in liver, heart or skeletal muscle. Cloning of overlapping cDNAs revealed that both transcripts encode the same open reading frame for a polypeptide of 191 amino acids. The deduced protein contains 4 EF-hand consensus motifs characteristic of calmodulin-like Ca(2+)-binding proteins. It displays 40% and 46% sequence identity with the retinal photoreceptor-specific Ca(2+)-binding proteins visinin and recoverin, respectively, and was termed VILIP (visinin-like protein). VILIP transcripts are also expressed in the retina. However, the expression pattern does not overlap with that of visinin or recoverin. The possible functional implications of the similarity to recoverin, which regulates guanylate cyclase activity of retinal rod cells in a Ca(2+)-dependent manner, are discussed.

Animals↗