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L Langbein

Publications and source records attributed to L Langbein.

At least 37 records · Page 2Linked to original sources
PubMed1997

The distribution of the desmosomal protein, plakophilin 1, in human skin and skin tumors.

Desmosomes are predominant among the types of plaque-bearing adhering junctions found in human skin. These structures contain a set of desmosomal cadherins and cytoplasmic plaque proteins, the synthesis of which is differentiation dependent. As plakophilin 1, a member of the armadillo gene family, is an important accessory desmosomal plaque protein, we raised several monoclonal antibodies specific for this protein and applied immunohistochemical and immunoblotting procedures to study the distribution of plakophilin 1 in desmosomes in adult and fetal skin, psoriatic epidermis, various epithelial skin tumors, and keratinocyte sheets grown in culture. In epidermis, the spinous layers were prominently immunostained by plakophilin 1 antibodies, whereas the basal cell layer was only weakly stained and the stratum corneum was entirely unstained. The staining observed in psoriatic epidermis was somewhat heterogeneous. In hair follicles, the outer root sheath (ORS) was delineated in its suprabasal cell layers, with variable staining in its upper and lower parts. All basal cells of the ORS remained unstained, as did upper inner root sheath (IRS) and matrix cells of lower bulb. In eccrine sweat glands, the reaction was confined to inner dermal ductal cells, with the acini remaining unstained. The desmosomal immunostaining observed in basal cell carcinomas (BCCs) and squamous cell carcinomas (SCCs) was very heterogeneous: In general, junctions in well-differentiated stratified tumor regions were more intensely stained than sections of poorly differentiated and invasively growing BCCs and SCCs. Plakophilin 1 was also prominent in the desmosomes of keratinocyte sheets grown in culture. The cell type-specific, i.e., differentiation-dependent, distribution of desmosomal plakophilin 1 is discussed in relation both to the stratification of the cutaneous epithelia and to tumor differentiation and growth.

Bowen's Disease↗
PubMed1997

Human type I cytokeratin genes are a compact cluster.

A YAC clone (211F11) containing approximately 0.5 Mb of human DNA was isolated from a human genomic library by PCR-based screening with cytokeratin (KRT) 13-specific primers. The YAC clone was mapped by FISH to the long arm of chromosome 17 (17q12-->q21), a region to which several other type I KRT genes had been mapped previously. We now show by Southern blot hybridization and PFGE analyses that KRT13, 14, 15, and 16 are all contained within YAC clone 211F11. Long-range restriction mapping analysis of clone 211F11 and of two smaller YAC clones that were also isolated with KRT13-specific primers, suggests that KRT13, 14, 15, 16 and their linked type I genes KRT17 and 19, are contained in less than 150 kb of genomic DNA. According to our reconstruction it then appears that at least six type I KRT genes are arranged in a highly compact cluster. The three YACs reported in this study represent a new tool to dissect the molecular structure of the locus of the human type I KRT genes.

Base Sequence↗
PubMed1996

Genomic characterization of the human type I cuticular hair keratin hHa2 and identification of an adjacent novel type I hair keratin gene hHa5.

Hair keratins, a subset of the keratin multigene family expressed in hard keratinizing structures, previously have been thought to comprise four members of each subfamily, designated Ha1-4 (type I) and Hb1-4 (type II), which are differentially expressed in the cuticle and cortex of the hair follicle. This report describes the genomic cloning and sequencing of the human type I cuticular hair keratin hHa2, as well as the identification of a previously unknown human type I hair keratin gene. The 12.5-kilobase pair genomic clone ghkI2.12, obtained by hybridization of a human genomic deoxyribonucleic acid library with a 3'-complementary deoxyribonucleic acid probe of hHa2, as well as the partially overlapping 14.4-kilobase pair genomic clone ghkI2.17, isolated using a 5'-fragment of clone ghkI2.12, allowed the characterization of the entire hHa2 gene. The gene displays the same exon/intron structure as two previously characterized type I mouse and sheep hair/wool keratin genes with strict positional conservation of the six introns in the region coding for the central alpha-helix. At the 5'-extremity of clone ghkI2.17, i.e., approximately 8.0 kilobase pairs upstream of the hHa2 gene and oriented in the same transcriptional direction, lies the gene for a hitherto unknown human type I hair keratin. Clone ghkI2.17 contains partial sequence information for this gene beginning with intron 5 and extending to the end of the gene. Screening of a human scalp complementary deoxyribonucleic acid library with a 3'-fragment of the gene yielded a full length complementary deoxyribonucleic acid clone of the new hair keratin, which in continuation of the current nomenclature for hair keratins was termed hHa5. Remarkably, the hHa5 gene, which contains an additional 7th intron in its 3'-noncoding region, is expressed mainly in supramatricial cells and lowermost cortical cells of the hair bulb and thus constitutes a very early component of hair morphogenesis. Our results confirm the type specific clustering of keratin genes and indicate that the human type I hair keratin subfamily contains more members than previously assumed.

Amino Acid Sequence↗
PubMed1995

Integrin receptors and their relationship to cellular proliferation and differentiation of oral squamous cell carcinoma. A quantitative immunohistochemical study.

The expression of extracellular matrix (ECM) proteins (fibronectin, laminin, collagen IV) and ECM receptors of integrin type (alpha 2 beta 1, collagen receptor; alpha 6 chain of the fibronectin receptor; alpha 6 chain of the laminin receptor) were examined in normal oral squamous epithelium and in invasive areas of squamous cell carcinomas with various differentiation and proliferation activities (Ki-67 antigen labelling), evaluating the presence, quantity (using an image analysis system) and distribution of the integrin subunits. In the mucosa, there was uniform immunostaining for alpha 2 beta 1 and alpha 6 concentrated at the cell membrane in the basal/supra basal cell zone, whereas, alpha 5 showed a discontinuous staining of the basal cell-basement membrane interface. alpha 2 and alpha 6 could be visualized in all carcinomas. alpha 5 showed low expression preferentially in less differentiated carcinomas. In contrast to normal mucosa, there was an increase in alpha 6 staining in well-differentiated carcinomas. Dedifferentiation of oral carcinomas was accompanied by an increase in cellular proliferation and with a decrease in alpha 2 beta 1 and alpha 6 staining. This reduction of alpha 6 staining was shown to be statistically significant, suggesting that this integrin may be a valuable grading parameter for oral squamous cell carcinoma.

Basement Membrane↗
PubMed1994

Epidermolytic palmoplantar keratoderma cosegregates with a keratin 9 mutation in a pedigree with breast and ovarian cancer.

Epidermolytic palmoplantar keratosis (EPPK) cosegregates with breast and ovarian cancers in a large French pedigree, raising the possibility that a single genetic mutation might cause these conditions and offering a potential lead to the identification of a hereditary breast/ovarian cancer gene. We have performed linkage analysis and show that the EPPK locus lies on the long arm of chromosome 17 near the type I keratin gene cluster and the proposed breast cancer gene (BRCA1). The type I keratin 9 gene has been partially sequenced in four affected individuals. A single base mutation within the rod domain of the protein cosegregates with EPPK in all affected individuals tested. Although inheritance of this mutation is likely responsible for EPPK, it is unlikely to be the cause of the breast and ovarian cancer.

Adolescent↗
PubMed1994

Keratin 9 gene mutations in epidermolytic palmoplantar keratoderma (EPPK).

We have isolated the gene for human type I keratin 9 (KRT9) and localised it to chromosome 17q21. Patients with epidermolytic palmoplantar keratoderma (EPPK), an autosomal dominant skin disease, were investigated. Three KRT9 mutations, N160K, R162Q, and R162W, were identified. All the mutations are in the highly conserved coil 1A of the rod domain, thought to be important for heterodimerisation. R162W was detected in five unrelated families and affects the corresponding residue in the keratin 14 and keratin 10 genes that is also altered in cases of epidermolysis bullosa simplex and generalised epidermolytic hyperkeratosis, respectively. These findings provide further evidence that mutations in keratin genes may cause epidermolysis and hyperkeratosis and that hyperkeratosis of palms and soles may be caused by different mutations in the KRT9 gene.

Amino Acid Sequence↗
PubMed1993

Molecular characterization of the body site-specific human epidermal cytokeratin 9: cDNA cloning, amino acid sequence, and tissue specificity of gene expression.

Differentiation of human plantar and palmar epidermis is characterized by the suprabasal synthesis of a major special intermediate-sized filament (IF) protein, the type I (acidic) cytokeratin 9 (CK 9). Using partial amino acid (aa) sequence information obtained by direct Edman sequencing of peptides resulting from proteolytic digestion of purified CK 9, we synthesized several redundant primers by 'back-translation'. Amplification by polymerase chain reaction (PCR) of cDNAs obtained by reverse transcription of mRNAs from human foot sole epidermis, including 5'-primer extension, resulted in multiple overlapping cDNA clones, from which the complete cDNA (2353 bp) could be constructed. This cDNA encoded the CK 9 polypeptide with a calculated molecular weight of 61,987 and an isoelectric point at about pH 5.0. The aa sequence deduced from cDNA was verified in several parts by comparison with the peptide sequences and showed the typical structure of type I CKs, with a head (153 aa), and alpha-helical coiled-coil-forming rod (306 aa), and a tail (163 aa) domain. The protein displayed the highest homology to human CK 10, not only in the highly conserved rod domain but also in large parts of the head and the tail domains. On the other hand, the aa sequence revealed some remarkable differences from CK 10 and other CKs, even in the most conserved segments of the rod domain. The nuclease digestion pattern seen on Southern blot analysis of human genomic DNA indicated the existence of a unique CK 9 gene. Using CK 9-specific riboprobes for hybridization on Northern blots of RNAs from various epithelia, a mRNA of about 2.4 kb in length could be identified only in foot sole epidermis, and a weaker cross-hybridization signal was seen in RNA from bovine heel pad epidermis at about 2.0 kb. A large number of tissues and cell cultures were examined by PCR of mRNA-derived cDNAs, using CK 9-specific primers. But even with this very sensitive signal amplification, only palmar/plantar epidermis was found positive. By in situ hybridization and immunolocalization we further showed that CK 9 is only expressed in the suprabasal cell layers of this special epidermal tissue. We discuss the molecular properties of CK 9 and its cell type- and body site-specific expression in relation to the special differentiation of palmar/plantar epidermis and to diseases specific for this body site.

Amino Acid Sequence↗
PubMed1993

Laminin matrix formation and S-100 protein and/or desmin-positive cells in malignant fibrous histiocytoma (MFH).

16/30 human storiform-pleomorphic malignant fibrous histiocytomas (MFH) showed a focal pericellular immunostaining for laminin. 14/16 of these laminin-positive tumours additionally revealed an atypical cellular differentiation (desmin- and/or S-100 protein-positive cells). The significance of focal laminin positivity along with atypical, non-entity specific differentiated cells is discussed before the background of laminin as being an indicator and promoter of differentiation in MFH. The limited value of a laminin detection in MFH for solving differential diagnostic questions (MFH versus other poorly differentiated sarcomas with basement membrane formation) has been pointed out.

Cell Differentiation↗
PubMed1991

Differentiation dependent matrix formation (fibronectin and laminin) in an experimental murine rhabdomyosarcoma model.

Cellular differentiation processes along with formation of extracellular matrix proteins were investigated in methylcholanthrene-induced murine rhabdomyosarcomata. We used primary tumours, allotransplants in nude mice, and the respective tumour recurrences generated by repeated incomplete surgical tumour removal. The expression of the differentiation markers desmin and myoglobin as well as the presence of fibronectin and laminin was ascertained by immunohistochemical methods. The question arises, whether or not correlations between the grade of cellular differentiation (desmin, myoglobin) and extracellular matrix formation (fibronectin, laminin) exist in tumours with striated muscle cell differentiation. The constant relations between cellular differentiation and matrix formation in original tumours also applied to allotransplants and tumour recurrences in which partially modulations of differentiation in comparison with original tumours could be recognized.

Animals↗
PubMed1990

Experimental rhabdomyosarcoma with regions like malignant fibrous histiocytoma (MFH)--a true double phenotypic pattern?

In murine sarcomas induced by 20-methylcholanthrene, histological features of malignant fibrous histiocytoma (MFH) as well as rhabdomyosarcoma were found in the same tumour both at light microscopy and at ultrastructural level. The areas showing rhabdomyomatous differentiation expressed vimentin, desmin, muscle-specific alpha-actinin, and sometimes myoglobin, but in the MFH areas only vimentin was expressed. A series of allografts in athymic mice, using tumour areas of both histological types, showed in every case a mixed pattern of tumour growth, whether the transplanted tissue was of MFH or rhabdomyosarcomatous type. This suggests that the MFH areas in the original experimental sarcomas were modulated disguised rhabdomyosarcomas. The significance of MFH-like areas in non-related soft tissue sarcomas is also discussed.

Animals↗
PubMed1990

Experimentally induced murine rhabdomyosarcomas--correlation between cellular contacts, matrix formation and cellular differentiation.

Rhabdomyosarcomas (RMSs) consist of a mixture of primitive mesenchymal cells as well as cells showing various stages of rhabdomyomatous differentiation. The qualitative and quantitative degree of the rhabdomyomatous differentiation of the cells, evaluated by their morphology and expression of defined structural and functional proteins, is accepted as the basis of diagnosis and is considered to be related to the biological behaviour of RMSs. Therefore we investigated solid experimentally induced murine RMSs, adherent (subconfluent, confluent) cell cultures obtained therefrom, and also suspension cultures and studied the expression of muscular differentiation markers (vimentin, desmin, myoglobin) and the formation of extracellular matrix components (fibronectin, laminin). When we compared solid tumours with adherent cell cultures of decreasing cell densities (confluent up to single cells) and with cells grown in suspension, we found a gradual decline of differentiation ("dedifferentiation"). This decline paralleled the decrease of cell-cell and cell-substrate contacts. In suspension cultures, cells were prevented from interacting with each other and the substratum, no rhabdomyomatous differentiation of the cells took place. If restoration of cellular contacts was allowed, either by adherent growth or by reinoculation into nude mice, the process of dedifferentiation was completely reversible. Consequently, it was demonstrated that the increase of cell-cell and cell-substrate contacts was strongly associated with the appearance or increasing expression of the desmin intermediate filament cytoskeleton and with formation of the extracellular matrix components fibronectin and laminin. The microfilament (F-actin) system was modulated from an impressive stress-fiber system in subconfluent to a dense network in confluent monolayers. The extent of cell-substrate contacts, mediated by extracellular matrix components, and the number of cell-cell interactions are responsible for the capability of a malignant mesenchymal cell, which is able to undergo rhabdomyomatous differentiation, to achieve the various stages of maturation.

Animals↗
PubMed1990

Transient cytokeratin expression in skeletal muscle during murine embryogenesis.

Cytokeratin expression was investigated in paravertebral skeletal musculature of 10 d and 18 d old embryos as well as in adult NMRI-mice. The muscular nature of the evaluated tissue was evidenced by their expression of vimentin and desmin. Binding moieties for cytokeratin antibodies (polyclonal and monoclonal) could be demonstrated only in muscle cells of 10 d old embryos. Concerning subtypes, the mouse equivalents of the human cytokeratins Nos. 8, 18 and 19 could be made probable. The importance of the transient cytokeratin expression in murine embryonal skeletal muscle cells is emphasized, because this intermediate filament type is expressed in rhabdomyosarcomas too.

Animals↗
PubMed1989

Papillary serous cystadenoma of the testis.

A case is presented of a 50-year old man with a unilocular cystic intratesticular tumour exhibiting the morphological features demanded from WHO for the diagnosis of serous papillary cystadenoma of the ovary. Keratin filaments could be demonstrated in the cyst lining and papillae covering cells by means of PAP-technique; AFP and SP-1 were lacking. The epithelial cells of the tumour showed a lectin binding pattern (WGA, UEA-I, PNA, Con A, PSA, LCA, RCA) different from the epithelium of rete testis and epididymis. We intend to classify our tumour as the male analogue of the respective ovarian growth.

Cystadenoma↗
PubMed1989

Lectin histochemistry of experimental murine rhabdomyosarcomas.

Methylcholanthrene-induced murine rhabdomyosarcomas and skeletal muscle of 10 and 18 d old murine embryos were investigated by lectin histochemistry (WGA, RCA-I, LCA, Con-A, PSA, UEA-I, PNA) and by immunohistochemistry (vimentin, desmin, myoglobulin). In rhabdomyosarcomas as well as in the developing skeletal muscle a clear trend was visible. A decrease of vimentin positivity and an increase of desmin positivity were associated with a diminution of binding sites for WGA, RCA, and LCA. No binding moieties for these lectin could be demonstrated in myoglobin positive normal and neoplastic rhabdomyomatous cells at all. The homologous expression or absence of markers reflected the cellular variability in rhabdomyosarcomas and may be explained as a phenomenon of different tumor cell maturation. The results show that rhabdomyosarcomatous cells are imitating the normal skeletal muscle development.

Animals↗
PubMed1989

Cytokeratin expression in experimental murine rhabdomyosarcomas. Intermediate filament pattern in original tumors, allotransplants, cell culture and re-established tumors from cell culture.

Soft tissue sarcomas were induced by 20-methylcholanthrene in NMRI-mice. The tumors were characterized as rhabdomyosarcomas by light and electron microscopy as well as immunohistochemistry (vimentin, desmin and myoglobin expression). Cytokeratins could be demonstrated by a panel of different poly- and monoclonal antibodies in original rhabdomyosarcomas, their allotransplants and the re-established tumors from cell culture in nude mice. The cytokeratin positive tumor cells were arranged in small clusters and/or haphazardly single dispersed in the rhabdomyosarcomas. By means of monoclonal antibodies cytokeratins No. 8 and No. 19 could be evidenced and cytokeratin No. 18 could be made probably. Behind the background of cytokeratin expression in developing fetal cross striated muscle cells our findings are discussed as a reminiscence of embryonal muscle development in these tumors. The significance of cytokeratin expression in rhabdomyosarcomas for diagnostic histopathology is emphasized.

Animals↗
PubMed1989

Histological and immunohistochemical findings in experimental rhabdomyosarcomas. Comparisons between original tumors, tumor recurrences and allotransplants in nude mice.

Cellular heterogeneity, a regular property of malignant neoplasms, can constitute the basis for phenotypic shifting in malignant tumors. A disturbance of the balanced interactions as happens as result of all therapy measurements between tumor cell subpopulations and between tumor and host offers the possibility to profound changes on the basis of cellular heterogeneity. As tumor model we used methylcholanthrene-induced murine rhabdomyosarcomas, which were allotransplanted into nude mice. The original as well as the allotransplanted sarcomas were submitted repeated operative tumor mass reductions, comparable to an insufficient tumor surgery in man. The histology and the cellular differentiation were evaluated by light microscopy and immunohistochemical marker expression (vimentin, desmin and myoglobin). Our findings document that primary tumors, their recurrences after incomplete tumor removal, and allotransplants inclusive of their surgically induced recurrences were histologically and immunohistochemically not identical in every case when compared with each other, but despite the experimental procedures they retained basic criteria necessary for the rhabdomyosarcoma diagnosis. Changes in sarcoma histology and cellular marker expression are not only reflected by dedifferentiation but can also comprise differentiation (maturation) processes. After artificial breakdown of intratumoral cellular interactions and tumor/host relations, unknown sarcoma inherent factors directed to retaining basic properties obviously preponderate, at least for the moment, over accidental new cell clones with differing phenotypic characteristics, which could be expected by cellular heterogeneity and would result in a markedly changed tumor.

Animals↗