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S Scarpa

Publications and source records attributed to S Scarpa.

At least 73 records · Page 4Linked to original sources
PubMed1989

[Ultrastructural and immunoelectron microscopic study of the desmoplastic stroma in carcinoma of the breast].

Different collagen types (I, III, IV, V) were identified in breast carcinoma desmoplastic tissue by ultrastructural analysis and immunoelectronmicroscopy. Type V collagen is present as a 12 nm. fibril in the stroma, either adjacent to the basement membrane or concentrated around the thicker fibers. Myofibroblasts, fibroblasts and tumor cells can be its major producers. Its possible function as a bridge between different collagens can be utilized, with different finality, by the same cells that have produced it. Furthermore, type V collagen can be involved in tumor invasion of the stroma and in all directional movements of tumor cells, as already demonstrated for other extracellular matrix components.

Breast Neoplasms↗
PubMed1988

Expression and synthesis of fibronectin and laminin by an intestinal epithelial cell line.

An intestinal epithelial cell line (IEC-17), undergoing a process of progressive morphological differentiation, was analysed for expression and synthesis of the extracellular matrix glycoproteins, fibronectin (FN) and laminin (LM). FN and LM cell surface expression was detected by immunoelectron microscopy, while intracytoplasmic accumulation was shown by immunofluorescence. 35S-methionine metabolic labelling was also performed to demonstrate FN and LM synthesis by IEC-17. We have compared two different maturation stages of the cell culture and have found that either early epithelial monolayer cells or later multistratified organoid structure cells expressed and produced large amounts of both proteins. These results indicate that FN and LM are constantly present during the process of IEC-17 organoid maturation: we can hypothesize that the two proteins act as mediators of cell to cell and cell to substrate adhesion interactions and, probably, have an active regulatory role in the process of intestinal epithelial cell differentiation.

Animals↗
PubMed1988

Study of immune complexes in bronchoalveolar lavage fluids.

Immune complexes (IC) were investigated in the bronchoalveolar lavage fluid (BAL) of 5 patients with hypersensitivity pneumonitis (HP), 11 with idiopathic pulmonary fibrosis (IPF) and 16 with sarcoidosis (S) by three different methods: C1Q-BA, KgB, AKgB-MA. Using AKgB-MA, it is possible to identify the class of antibodies forming the IC. IC were present in all cases of HP, in 8/11 (73%) of IPF and in 10/16 (62%) of S. However, the three tests showed discordant results for the three different diseases: C1Q-BA and KgB-SP were both positive in 40%, AKgB-MA in 80% of HP cases; C1Q-BA in 73%, KgB-SP in 9% and AKgB-MA in 46% of IPF cases; C1Q-BA in 31%, KgB-SP in 12% and AKgB-MA in 31% of S cases. In all of the diseases, the IC were mostly composed of IgG; moreover, in HP IgA was also frequently present. The determination of IC in different fractions obtained from BAL ultracentrifugation, confirmed the simultaneous presence of IC of different molecular weights and antibody composition. Lung transbronchial biopsy with immunofluorescence showed immunoglobulin, prevalently IgG, and C, in all HP cases, the majority of IPF cases and 50% of S cases. This confirms the importance of IC in the pathogenesis and/or evolution of some pulmonary diseases.

Adult↗
PubMed1988

Small cell lung cancer cell lines: pure and variant types can be distinguished by their extracellular matrix synthesis.

Variant subclasses of cell lines derived from small cell lung cancers have previously been characterized, having distinctive biochemical, morphological and growth properties compared to the classic lines. Both types of small cell lung cancer express features suggesting that they are derived from neuroectodermal cells. We compared the capacity of these two types of lung cancer cell lines to synthesize the extracellular matrix glycoproteins, fibronectin and laminin, and also analysed a few other non-small cell lung cancer lines, as controls. We found that the cell lines of the pure type did not produce laminin or fibronectin, whereas the cell lines of the variant type synthesized laminin, and the non-small cell lung cancer lines produced either laminin or fibronectin. These findings suggest that the variant form of small cell lung cancer may be derived from a primitive neuroectodermal cell, with both neural and epithelial features, whereas the classic type is derived from a more mature cell with predominantly neuronal features. The differences in extracellular matrix synthesis, and laminin in particular, may explain some of the in vitro and in vivo characteristics of the tumour.

Carcinoma, Non-Small-Cell Lung↗
PubMed1987

Ewing's sarcoma lines synthesize laminin and fibronectin.

Immunoelectron microscopy was employed to detect laminin and fibronectin cell surface expression on five Ewing's sarcoma lines plus a normal fibroblast line as control. Monospecific antibodies to both glycoproteins were detected on tumour cell and fibroblast layers with colloidal gold--protein A conjugates. All five tumour lines were positive for fibronectin and/or laminin, whereas the fibroblast line expressed fibronectin only, as expected. Fibronectin displayed a dense granular pattern, typically in the cell-cell and cell-matrix adhesion areas; laminin displayed a punctate pattern. 3H-leucine metabolical labelling was also used to demonstrate laminin and fibronectin synthesis. The labelled proteins released in the culture media were separated by molecular weight on SDS-PAGE and identified by immunoprecipitation with the monospecific antibodies. The results substantiated the immunoelectron microscopy data. These findings indicate that Ewing's sarcoma lines produce a complex extracellular matrix including fibronectin and laminin, in addition to the collagens described by other workers. Histogenetic classification of this tumour in terms of extracellular matrix proteins synthesis is thus more difficult than has been supposed. The same complexity must also be borne in mind when using the matrix components as an aid to Ewing's sarcoma differentiation from other childhood tumours.

Cell Line↗
PubMed1987

Extracellular matrix synthesis by undifferentiated childhood tumor cell lines.

The authors have examined extracellular matrix (ECM) biosynthesis by small round cell tumors of childhood. Basal lamina (laminin and Type IV collagen) and stroma (collagens I, III, and V and fibronectin) constituents were studied. It was found that these tumors synthesize ECM in characteristic patterns. Five Ewing's sarcomas variably synthesized small amounts of all ECM constituents except Type V collagen. All eight neural tumors (neuroblastoma and primitive neural tumors) synthesized fibronectin (unlike some Ewing's sarcomas), as well as laminin and Type IV collagen (2 cases lacked Type IV collagen synthesis). No stromal (I/III) collagen synthesis was observed by neural tumors. All soft tissue sarcomas except an embryonal rhabdomyosarcoma synthesized stromal collagens and often laminin or fibronectin as well. Lymphomas synthesized no ECM of any kind. The synthesis of stromal collagens by sarcomas but not neural tumors serves to distinguish these two tumor types, especially Ewing's sarcoma from neuroblastoma. The presence of any ECM synthesis excludes lymphoma from diagnostic consideration.

Child↗
PubMed1987

Differentiation of human neuroblastoma recapitulates neural crest development. Study of morphology, neurotransmitter enzymes, and extracellular matrix proteins.

Differentiation of human neuroblastoma (NB) was studied in vitro with five NB cell lines treated with dibutyryl cyclic adenosinemonophosphate and retinoic acid. Although the above agents induced different responses in the various cell lines, three overall morphologic phenotypes emerged: a neuronal, characterized by cell processes and neurosecretory granules, a flat cell without pigment, which displayed basal lamina pertinent to Schwann cells, and a flat pigmented cell which exhibited melanosomes, similarly to melanocytes. The activity of the Schwann cell enzyme cyclic nucleotidyl phosphohydrolase increased considerably in one condition, after induction of a predominantly flat cell phenotype. All studied NB cell lines were capable of synthesizing and expressing the extracellular matrix proteins laminin (LM), fibronectin (FN), and Type IV collagen; but a specific pattern of expression emerged after differentiation, which was proportional to normal tissue equivalents: neuronal--none; melanocytic--FN only; and Schwann cell--large amounts of FN, LM, and Type IV collagen.

2',3'-Cyclic Nucleotide 3'-Phosphodiesterase↗
PubMed1986

Distribution of tissue-specific tightly bound non-histone proteins in the first level of repeating chromatin structures.

Non-histone proteins, tightly bound to DNA, have been extracted from whole chromatin and core particles prepared from pig liver or kidney. We have investigated by bidimensional slab gel electrophoresis the distribution of this protein class in the first level of repeating structure of chromatin. Our results reveal that non-histone proteins tightly bound to DNA are a heterogeneous protein class. Some of them, particularly in the core particles, appear to be essentially the same in both tissues, though having differences in their isoelectric point, which may be attributed to postsynthetic modifications. We have calculated that this protein class is associated to only 10% of nucleosomes, these nucleosomes having, on the average, one protein molecule for each core DNA. The tissue-specific proteins have high molecular mass (ranging from 135 kDa to 70 kDa in liver, over 135 kDa in kidney) and, in kidney, a more basic isoelectric point. These proteins are mainly located outside the core particles; they could be situated in the spacer regions and/or be involved in determining higher levels of chromatin organization.

Amino Acids↗
PubMed1986

Replacement of 5-methylcytosine by cytosine: a possible mechanism for transient DNA demethylation during differentiation.

In an earlier study it was discovered that when Friend erythroleukemia cells (FELC) were exposed to a variety of chemical agents capable of inducing differentiation, their DNA underwent genome-wide transient demethylation. In an attempt to elucidate the biochemical mechanism responsible for this phenomenon we have induced FELC with 5 mM hexamethylenebisacetamide and labeled the DNA in vivo with a density label, 5-bromodeoxyuridine, and a radioactive label, deoxy[5-3H]cytidine. Newly replicated DNA (heavy-light) was separated from parental DNA (light-light) by isopycnic centrifugation. Incorporation of deoxy[5-3H]cytidine into light-light duplex DNA has been observed only in induced cells concomitantly with the demethylation of the DNA, whereas, in parallel experiments, deoxy[G-3H]adenosine was not incorporated into light-light DNA. It was also found that the labeling of light-light DNA with deoxy[5-3H]cytidine is transient since the 3H label was removed from the DNA during the period of de novo DNA methylation that follows the demethylation. These results, taken together, strongly suggest that the demethylation of the DNA during differentiation is achieved by an enzymatic mechanism whereby 5-methylcytosine is replaced by cytosine.

5-Methylcytosine↗
PubMed1986

Prostaglandin-induced storage and secretion of esteroproteases in the mouse submaxillary gland.

The submaxillary glands of adult C3H mice which received intraperitoneal injections of prostaglandins F2 alpha and E2 (PGF2 alpha and PGE2) were examined biochemically and ultrastructurally. Results indicated that the specific activity of esteroprotease in an homogenate of submaxillary glands was significantly increased when mice were treated with PGF2 alpha (96 or 480 micrograms/kg), and decreased when they were treated with PGE2 (96 or 480 micrograms/kg). Ultrastructural findings were correlated with these biochemical data. Thus, it appeared that PGF2 alpha stimulated the secretion and synthesis of bioactive proteins, and that PGE2 stimulated only the secretion.

Animals↗
PubMed1985

The differentiation of L5/A10 myoblast cell line (a subclone of L5 line) is controlled by changes of culture conditions.

We report here that it is possible to induce differentiation in a subline of L5 myoblast line (L5/A10) by manipulating the culture media. When L5/A10 myoblast are cultured in F14 supplemented with 10% fetal calf serum the cells grow with a division time of 12 h and reach confluency at a cell density of approximately 2.4 X 10(5) cells per cm2, without undergoing differentiation, characterized, morphologically, by formation of multinucleated fibers, and biochemically, by the synthesis of muscle specific proteins such as creatine phosphokinase or myokinase. However, cells, grown in F14 + 10% fetal calf serum, will undergo regular differentiation after a limited number of division when transferred to F14 medium supplemented with limiting concentrations (1-2%) of fetal calf serum. Investigations of the biochemistry of myoblast differentiation in cell culture will be facilitated by the availability of a cell line that can undergo differentiation under controlled conditions.

Adenylate Kinase↗
PubMed1984

Differentiation of myoblast cell lines and biological methylation: 3-deazaadenosine stimulates formation of multinucleated myofibers.

Treatment of myoblast cell lines with 3-deazaadenosine stimulates differentiation into myofibers. Myoblast clone L5/ 3B5 , which does not form myofibers after 6 days in fusion medium, was stimulated to form myofibers after 5 days of culture in fusion medium containing 50 microM 3-deazaadenosine. Myoblast clone L5/ 3C4 , which normally begins to form myofibers after 4 days in fusion medium, was stimulated by 50 microM 3-deazaadenosine to form myofibers after 3 days in culture and the extent of fusion was also increased. In the presence of 100 microM homocysteine thiolactone, the concentration of 3-deazaadenosine that stimulated maximal fusion was reduced by a factor of 10, from 50 microM to 5 microM 3-deazaadenosine. Stimulation of myofiber formation by 3-deazaadenosine suggests a requirement for one or more methylation reactions in myoblast differentiation and the potentiation by homocysteine thiolactone indicates that myofiber formation is specifically stimulated by an intracellular accumulation of 3-deazaadenosylhomocysteine.

Adenosine↗
PubMed1984

Type V collagen in human amnion is a 12 nm fibrillar component of the pericellular interstitium.

Immunoelectron microscopy was utilized to detect type V collagen in human amnion. Monospecific antibodies to type V collagen were detected with protein A-gold conjugates in tissue sections and epoxy-embedded sections of human amnion. Type V collagen was localized to the immediate vicinity of the basal lamina, but was distinct from laminin and type IV collagen, which localized only to the lamina lucida and lamina densa, respectively, of the basal lamina. At high magnification, 12 nm unbanded fibrils were seen to be labelled by anti-type V collagen antibody; these fibrils extended from the lamina densa of the basal lamina well into the interstitial matrix. In comparison, only the amorphous matrix of the lamina densa showed labelling with anti-type IV collagen antibodies. Anti-laminin antibodies labelled the lamina lucida. Quantitative analysis of grain distribution revealed the laminin labelling to be centered over the distal half of the lamina lucida (mean distance from the cell surface = 70 nm). In contrast, type IV collagen was centered over the lamina densa (mean = 115 nm). Both distributions were essentially Gaussian and distinct from the broad distribution of type V collagen. Type I collagen fibers with characteristic 67 nm periodicity were unlabelled with antibodies to type V collagen, although labelled type V fibrils were frequently enmeshed among the type I fibers. Antibodies to type I collagen labelled these fibers but not the type V fibrils. The results indicate that in human amnion, type V collagen is a 12 nm diameter, unbanded fibril which extends from the lamina densa of the basal lamina into the adjacent interstitial matrix. We hypothesize that type V collagen functions as a network of anchoring fibrils between the cell basal lamina and the extracellular matrix, especially type I collagen fibres. Type V collagen thus appears to be a unique interstitial collagen.

Amnion↗
PubMed1981

Changes in myosin and myosin light chain kinase during myogenesis.

Myosins and myosin light chain kinases have been isolated from a cloned line of myoblasts (L5/A10) as this cell line undergoes differentiation toward adult muscle. At least three myosin isozymes were obtained during this developmental process. Initially a nonmuscle type of myosin was found in the myoblasts. The molecular weights of the myoblast light chains were 20 000 and 15 000. Myosin isolated from early myotubes had light chains with molecular weights of 20 000 and 19 500. Myosin isolated from myotubes which contained sarcomeres had light chains with molecular weights of 23 000, 18 500, and 16 000. This last myosin was similar in light chain complement to adult rat thigh muscle. Two forms of the myosin light chain kinase activity were detected: a calcium-independent kinase in the myoblasts and a calcium-dependent kinase in the myotubes with sarcomeres. No myosin light chain kinase activity was detected in the early myotubes.

Actomyosin↗
PubMedDate not supplied

Xenotransplantation in immunosuppressed nude mice of human solid tumors and acute leukemias directly from patients or in vitro cell lines.

Athymic nude (nu/nu) mice are widely employed for the heterotransplantation of human tumor cell lines established in vitro and tumor cells directly grafted from patients. By contrast, hemopoietic malignancies have consistently proved difficult to transplant and well-characterized human leukemias suitable for studies in nude mice are scarce. We report here our experience with subcutaneous xenotransplantation of human neoplastic cells into nu/nu mice immunosuppressed through sublethal irradiation and splenectomy (SI-nu/nu) and with an additional injection of anti-Asialo-GM1 antibodies (SIA-nu/nu) in order to eliminate natural killer activity. Thirteen out of 16 continuous cell lines established in vitro from solid tumors and 7 out of 14 human tumors obtained from fragments of surgical specimens formed a progressively growing tumor in SI-nu/nu mice. Six out of 8 in vitro established human leukemic cell lines and 5 out of 18 neoplastic hematopoietic cells directly xenotransplanted from the patient grew SIA-nu/nu mice. When the membrane and chromosome markers of neoplastic cells that grew into the mice were evaluated, only marginal differences with those of the original tumors were found. In addition, when interfering factors alter the histological aspect of the primary tumor, xenotransplantation may also be of some help in histological diagnosis. By using SI- and SIA-nu/nu mice, it is thus possible to build up several new in vivo experimental systems with fresh human tumors that may be of value in studying the efficacy of differentiation factors and immunological maneuvers on the in vivo growth of human tumors.

Animals↗