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F Ruggiero

Publications and source records attributed to F Ruggiero.

At least 37 records · Page 2Linked to original sources
PubMed1994

Interactions between cells and collagen V molecules or single chains involve distinct mechanisms.

Acid-soluble and pepsin-treated collagen V were prepared from fetal human bones or human placenta, respectively, to be tested for potential cell adhesion promoting activity. Out of 14 different collagen I-adhering cell lines, 10 showed distinct adhesion to collagen V. In all cases adhesion was followed by spreading. The activities of intact and pepsin-solubilized collagen V were similar, suggesting that the cell binding sites are restricted to the triple-helical domain of the molecules. Cell adhesion was also induced by the unfolded form of collagen V and after separation of the alpha chains by heparin affinity chromatography. Isolated alpha 2(V) chains, rich in RGD sequences, were more efficient than isolated alpha 1(V) chains. However, cell adhesion to native or denatured collagen V did not proceed by the same molecular mechanisms as shown by cell adhesion inhibition experiments. Cell adhesion to native collagen V was insensitive to the presence of RGD-containing synthetic peptides while adhesion to denatured collagen V was inhibited by the peptides. Furthermore, the results strongly suggested a major role for alpha 1 beta 1 and alpha 2 beta 1 integrins in the RGD-independent cell adhesion to native collagen V. These data indicate that collagen V is a specific adhesive substrate for different cell types. It also suggests that distinct sets of RGD-dependent and RGD-independent receptors mediate cell attachment to unfolded and native collagen V, respectively. This mechanism is shared by at least the interstitial collagens I and VI, which supports the hypothesis that when included in the triple-helical conformation of collagens, RGD sequences are either not accessible to cells or exhibit specific conformations recognized by different integrins.

Actins↗
PubMed1994

Identification and characterisation of a novel repetitive antigen from Onchocerca spp.

A novel repetitive antigen from the cattle parasite Onchocerca gibsoni was shown to be recognised by sera from humans infected with Onchocerca volvulus, Wuchereria bancroftii or Brugia malayi. The O. gibsoni protein was produced in a recombinant form, and antibodies raised to this protein used to screen cDNA libraries for O. volvulus. A series of clones were isolated which encoded repetitive regions very similar to those in O. gibsoni, but interspersed between these were longer repeating units which we have not so far found in O. gibsoni. The repetitive antigen was shown to be of high molecular weight and present only in the insoluble (membrane) fraction of O. gibsoni microfilariae. Immunofluorescence techniques demonstrated that the antigen was associated both with muscle and with specific membrane layers, including a peripheral layer which corresponds to either the outer hypodermis or an inner region of the cuticle in adult female O. gibsoni. In many respects, the proteins encoded by the O. gibsoni and O. volvulus cDNA clones resembled repetitive antigens from several distantly related eukaryotic parasites, and a possible common role in immune evasion is discussed.

Amino Acid Sequence↗
PubMed1993

Composition and organization of the collagen network produced by fetal bovine chondrocytes cultured at high density.

Fetal bovine chondrocytes isolated from the resting zone of epiphyseal cartilage were maintained in high-density culture for 4 weeks. From Day 2 in culture, the chondrocytes deposited an extracellular matrix composed of Types II, IX, and XI collagen. Types IX and XI collagen were restricted to the pericellular domain from Day 5. By 2 weeks the entire cell layer stained for antibodies to Type II and IX collagens. Type XI could be demonstrated throughout the cell layer by pepsinization of the sections. Results from both rotary shadowing and immunochemistry showed that the fibrils formed in culture were heterotypic, with Type IX collagen arranged along the surface and with Type XI collagen buried in Type II fibrils. Nonspecific Type VI collagen and the glycoproteins tenascin and fibrillin, previously described in cartilaginous tissue, were identified by their ultrastructural characteristics in the cell layer homogenate. Although the cells presented morphological characteristics of chondrocytes and still expressed cartilage-specific collagens, the appearance of Type I collagen in the culture cell layer after 4 weeks of culture demonstrates a partial dedifferentiation of the chondrocytes. The culture system described in this report provides an interesting tool for maintaining chondrocytes in a cartilage-like matrix to study the influence of different physical and chemical factors on the expression and differentiation of the cells.

Animals↗
PubMed1991

Structure of the basement membrane of corneal epithelium: quick-freeze, deep-etch comparative study of networks deposited in culture and during development.

The basement membranes elaborated by corneal epithelium in the chick embryo and in culture conditions have been studied by quick-freezing and deep-etching methods. Electron microscope observations of en face unidirectional platinum shadow castings revealed a polygonal network comparable to the type IV collagen network described in human amniotic basement membrane and EHS mouse tumor matrix. The material deposited in culture contained type type IV collagen, as demonstrated by immunofluorescence labeling using anti-type IV collagen antibodies and formed delicate networks. Fine filaments and granules composing this network were interpreted respectively as linear and globular NC1 domains of the type IV collagen molecule. These loose networks were considered as first steps in basement membrane assembly. Staggered superimposition of comparable networks could lead to the dense network organization as observed for basement membranes in situ. These observations showed that the basement membrane of the chick embryo corneal epithelium is also organized in a complex polygonal framework that is preserved even when secreted in culture conditions.

Animals↗
PubMed1990

Extracellular matrix production by embryonic epithelium cultured on type IV collagen. Deposition of a primary corneal stroma-like structure containing large irregular type I fibrils without type II collagen.

The corneal stroma of the chick embryo is deposited in two steps. The primary stroma is laid down by the corneal epithelium and it contains type I, type II and type IX collagens. Its formation is subsequent to the presumptive epithelial cells' migration onto the lens capsule (which is rich in type IV collagen). The secondary, ultimate stroma is synthesized by fibroblasts which, on day 5 of development, invade the swollen primary stroma. It is composed of a matrix of thin (25 nm), regular fibrils containing type I and type V collagens. We found that a chick corneal epithelium isolated from either a 6-day or a 14-day embryo was able to produce, in vitro, stroma-containing type I collagen fibrils. However, the amount of collagen deposited and its organization were highly dependent on the substratum used. Plastic or purified bovine type I collagen substrata led to the release of very few fibrils. Purified human type IV collagen induced the production of an abundant matrix made of large irregular collagen fibrils. When compared to native corneal stroma, there were two aspects in which this matrix differed: (1) it contained only type I collagen, as shown by indirect immunofluorescence, and (2) there were numerous large, irregular fibrils of about 100 to 130 nm in diameter. In conclusion, it is suggested that purified type IV collagen substitutes, in part, for the basement membrane and allows the production of a corneal stroma-like matrix by an embryonic corneal epithelium in culture. This production is possible even with a 14-day epithelium which, in vivo, is no more involved in the synthesis of the stroma collagens. Moreover, the regulatory effect of type II collagen, previously suggested by in vivo observations, may be confirmed in this in vitro system by the appearance of large fibrils in the newly deposited stroma that are made only by type I collagen.

Animals↗
PubMed1990

Proteoglycan core protein and type II collagen gene expressions are not correlated with cell shape changes during low density chondrocyte cultures.

Chondrocytes isolated from chicken embryo sterna were cultivated in low density monolayer cultures to induce their dedifferentiation. At different stages of the long-term cultures, changes in expression of a cartilage-specific sulfated proteoglycan and cartilage-characteristic type II collagen have been examined and related to the shape change of cells using in situ hybridization and immunocytochemistry. At the beginning of the culture, all cells exhibit a round shape and express the cartilage phenotype. Then, during the course of the culture, chondrocytes flatten and become fibroblast-like, but this morphological modification does not start for all the cells at the same time. Interestingly, the loss of cartilage proteoglycan or type II collagen expression did not occur for all polygonal or fibroblast-like cells. Moreover, we observed a variability in the steady state levels of RNA or protein accumulation among chondrocytes exhibiting a similar shape, as judged by the intensity of hybridization signal or immunofluorescence over the cells. These observations support the hypothesis that the shape change does not have a causative role in the chondrocyte phenotype expression, but is rather a secondary effect of the dedifferentiation process. Furthermore, the disappearance of hybridizable core protein or type II collagen mRNA during the dedifferentiation process was coincident with the disappearance of the proteins for which they code as detected by immunohistochemical staining. This suggest that core protein and type II collagen gene expressions are controlled primarily at the transcriptional level in long-term chondrocyte cultures.

Aggrecans↗
PubMed1990

Anchorin CII, a collagen-binding chondrocyte surface protein of the calpactin family.

In an attempt to identify collagen-binding proteins on the chondrocyte surface, a protein of Mr 34KD, called Anchorin CII was isolated from chondrocyte membranes by affinity chromatography on type II collagen sepharose (Mollenhauer & von der Mark, 1983). The protein was localized on the chondrocyte surface by immunofluorescence labeling using a specific rabbit antibody (Mollenhauer et al., 1984), by immunogold labeling and by cell surface iodination (Pfäffle et al., 1988). Fab'fragments of anti anchorin CII reduced the binding of chondrocytes to type II collagen substrates (Mollenhauer et al., 1984). Analysis of the complete primary structure of anchorin CII revealed 4 repetitive domains of each 70-80 amino acid residues, and the absence of hydrophobic transmembrane sequences or signal peptides (Fernández et al., 1988). Thus, anchorin CII is another member of the calpactin/lipocortin/annexin family, although most other members of this family are located strictly intracellularly. Similar to lipocortin I, however, anchorin CII can be identified extracellularly, e.g. in the culture medium of chondrocytes and fibroblasts (Pfäffle et al., 1988). Here we report on further studies on sequence homologies to other annexins, and on the Ca(++)- and phospholipide binding of this protein.

Amino Acid Sequence↗
PubMed1988

Biosynthesis, secretion and extracellular localization of anchorin CII, a collagen-binding protein of the calpactin family.

The amino acid sequence of anchorin CII, a collagen-binding protein isolated originally from chondrocyte membranes, was previously determined by sequencing of cDNA and proteolytic fragments of the protein. Computer analysis of the protein sequence revealed four internal repeats of approximately 70-80 residues, each containing a highly conserved consensus sequence of 17 residues. These repeats show considerable homology with sequences in human and bovine calpactin, lipocortin, endonexin and protein II, which are members of a family of Ca2+- and phospholipid-binding proteins, as well as major substrates of tyrosine kinases. While these proteins have been located at the inner side of the plasma membrane of fibroblasts and epithelial cells, here we present experimental evidence that anchorin CII is at least partially released from cells and binds to the outer cell surface. Biosynthesis studies in cell-free systems and in cell culture indicate that anchorin CII is not processed, which is consistent with the absence of signal sequences from the protein. Yet, pulse-chase experiments show that anchorin is released into the culture medium of fibroblasts after 30 min, and in chondrocyte cultures after 20 h. Anchorin CII was located to the outer cell surface of chondrocytes by lactoperoxidase-catalyzed cell surface iodination as well as by antibody labeling both at light- and electron-microscopical level. The pericellular localization of anchorin CII is consistent with the notion that this protein is involved in the interaction of chondrocytes and fibroblasts with extracellular collagen.

Amino Acid Sequence↗
PubMed1988

Retention of carboxypropeptides in type-II collagen fibrils in chick embryo chondrocyte cultures.

An antibody reacting with the C-propeptide of chick type-II procollagen was used in an attempt to localize this terminal extension of the procollagen molecule (by immunogold labelling) during early collagen fibrillogenesis in chondrocyte cultures. After 2 days in culture the chondrocytes were surrounded by pericellular type-II collagen, as demonstrated by an indirect immunofluorescence labelling technique. An electron microscopy study of these cultures showed that the collagen fibrils were thin (approximately 15 nm diameter), with a poorly visible cross striation, sometimes enhanced by slight thickenings. The antibody against the C-propeptide of type-II procollagen labelled most of the collagen fibrils, according to a very regular pattern constituting a 60 nm periodicity. After 3 days the label was still present on the pericellular collagen fibrils but disappeared from the collagen fibrils of the extracellular matrix. Our results indicate that the C-propeptide of type-II procollagen is retained in the newly formed fibrils.

Animals↗
PubMed1988

Immunohistochemical study of colorectal adenomas with monoclonal antibodies against blood group antigens (sialosyl-Le(a), Le(a), Le(b), Le(x), Le(y), A, B, and H).

We studied 40 colorectal adenomas with monoclonal antibodies against blood group antigens (sialosyl-Le(a), Le(a), Le(b), Le(x), Le(y), A, B, and H). Sialosyl-Le(a), Le(a), Le(x), and Le(y) are usually present in different compartments of the crypts of normal colorectum and can be considered markers of normal differentiation antigens (NDA). The former two antigens represent markers for differentiated colonic epithelium and the latter two, markers for "undifferentiated" crypt base epithelium. Le(b), A, B, and H are normally absent from the distal colon and rectum, but are expressed by fetal colon and carcinomas and are considered oncofetal tumor-associated antigens (OF-TAA). Individual adenomas could be characterized as to whether or not they expressed OF-TAA and NDA. Of the adenomas, 35% were OF-TAA+/NDA+, 40% were OF-TAA+/NDA-, 17.5% were OF-TAA-/NDA+, and 7.5% were OF-TAA-/NDA-. When NDA were present, they were expressed in the same compartment of the crypt as in the normal colon and rectum. In adenomas there was proliferation of the undifferentiated enterocyte marker Lex throughout the entire length of the crypt when compared with controls (p less than 0.01). Of the adenomas, 75% expressed OF-TAA, however, 35% of adenomas concomitantly expressed NDA in the same distribution as normal colon and rectum indicating that adenomas have features of both carcinoma and normal colorectum epithelium.

Adenocarcinoma↗
PubMed1985

An ultrastructural study of the contact between type I collagen assemblies and the induced human platelet aggregates.

Several type I collagen assemblies have been tested for their ability to induce platelet aggregation: a molecular solution, native and reconstituted native-type fibrils, segment long spacing aggregates (SLS) and an unordered collagen multimer. The ultrastructure of the inducer has been observed before its introduction into the platelet suspension as well as within the final aggregates. The following results have been obtained: 1) platelet aggregation was induced by the monomeric solution of collagen only after a long lag phase. While the original solution did not contain fibrillar elements, the platelet aggregates were in contact with collagen filaments showing a faint banding pattern. The results confirm that the longer lag time recorded is necessary for the collagen to polymerize and that the monomeric collagen actually does not induce platelet aggregation; 2) native and reconstituted native-type fibrils, SLS and unordered collagen multimer similarly induce platelet aggregation and were not modified during the course of this phenomenon; 3) although the general ultrastructure of the contacts between platelet and collagen assemblies were similar, a difference was noted in the extent of contact: a focal zone with native-type fibrils, numerous zones of contact with SLS and very extensive contact with unordered multimer. These results suggest that the combination of three factors are necessary to trigger platelet activation by collagen: the nature of the active sites on collagen, the density of these sites and the geometry of the collagen assembly.

Animals↗
PubMed1985

Lipoatrophia semicircularis. Report of a case.

A case of lipoatrophia semicircularis is described in a 5-year-old child. Histological examination revealed the complete loss of adipose tissue. No associated abnormalities were found.

Child, Preschool↗
PubMed1984

A freeze-fracture and thin section study of the interaction of blood platelets with native type I collagen fibrils.

The membranes of non-activated and activated human blood platelets have been studied with freeze-fracture and conventional electron microscopy. Aggregated platelets activated by ADP or by native collagen fibrils did not show any intramembrane particle clustering. No intramembrane modification is detectable at the contact regions with collagen fibrils. However, a local densification of the cortical cytoplasm is noted in thin sections where platelets make contact with collagen fibrils. These results suggest that either the membrane receptor for collagen is not visualized by freeze-fracturing or that, as suggested previously, the binding site on collagen may not have a specificity and affinity as high as expected from a conventional receptor-ligand interaction.

Blood Platelets↗
PubMedDate not supplied

Carcinoid of the appendix during laparoscopic cholecystectomy: unexpected benefits.

Carcinoid tumors of the midgut arise from the distal duodenum, jejunum, ileum, appendix, ascending and right transverse colon. The appendix and terminal ileum are the most common location. The majority of carcinoid tumors originate from neuroendocrine cells along the gastrointestinal tract, but they are also found in the lung, ovary, and biliary tracts. We report the first case of elective laparoscopic cholecystectomy in which we found a suspicious lesion at the tip of the appendix and proceeded to perform a laparoscopic appendectomy. The lesion revealed a carcinoid tumor of the appendix.

Appendectomy↗