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Biomedical subjects

G Abatangelo

Publications and source records attributed to G Abatangelo.

60 records · Page 4Linked to original sources
PubMedDate not supplied

Clostridial collagenase releases bioactive fragments from extracellular matrix molecules.

The current study was designed to investigate the biological role of small extracellular matrix fragments in wound healing. Human burn eschar tissue was digested with bacterial collagenase, and small aminoacidic fragments were inoculated in both human dermal fibroblast cultures and polyvinyl alcohol sponges implanted subcutaneously in the rat. Proliferation assays on cell cultures and biochemical and histologic analyses of the animal model were then performed. Results showed that fibroblasts treated with low concentrations of eschar fragments duplicated significantly faster than controls. Biochemical and histologic data from sponge implants showed that the inflammatory response was augmented by eschar-derived fragments at postoperative day 2, whereas protein and hydroxyproline synthesis were decreased at day 14. In conclusion, these data substantiate that the application of bacterial collagenase to débride necrotic tissue may have an indirect healing effect resulting from the local release of bioactive matrix-derived fragments.

Animals↗
PubMedDate not supplied

Tumor necrosis factor-alpha (TNF-alpha) in seasonal allergic conjunctivitis and vernal keratoconjunctivitis.

PURPOSE: To quantify the presence of the proinflammatory cytokine tumor necrosis factor-alpha (TNF-alpha) in allergic conjunctivitis. MATERIALS AND METHODS: Tears and peripheral blood samples were collected from patients with seasonal allergic conjunctivitis (SAC, n=6), vernal keratoconjunctivitis (VKC, n=12), and normal subjects (CT, n=12). From an additional six nonactive allergic patients, tears were collected before and after specific conjunctival allergen challenge (CAC). Upper tarsal conjunctival biopsies were obtained from five CT and five VKC patients. TNF-alpha in tears was measured by enzyme-linked immunoassay and identified in tissues by immunohistochemistry. RESULTS: Tear TNF-alpha levels in VKC patients were significantly increased compared to CT (p=0.03), and were significantly correlated with the severity of the disease. No differences were found between SAC and CT tear samples. TNF-alpha serum levels were higher in VKC than CT, however, this difference was not statistically significant. After CAC, tear TNF-alpha levels were found increased in only one of six patients. In VKC tissues, TNF-alpha positive cells were significantly increased compared to CT (p=0.03). CONCLUSIONS: TNF-alpha may have a significant role in severe forms of allergic conjunctivitis.

Adolescent↗
PubMedDate not supplied

Comparison of the effects of intra-articular injections of Hyaluronan and its chemically cross-linked derivative (Hylan G-F20) in normal rabbit knee joints.

OBJECTIVE: Intraarticular injection of native hyaluronan (HA) or a cross-linked derivative are commonly utilized in the treatment of osteoarthritis. Unlike from native hyaluronan, the crosslinked HA derivative is a gel containing also other chemical entities. This study compares the local tolerability of these different preparations in normal rabbit knees, in order to provide further information on their biological effects. METHODS: Synovial fluids were aspirated after single or repeated weekly injections (up to three) of the therapeutic agents and cell count was determined in a Burker chamber and in an automatic cell counter. The percentage of the different cell types was determined by light microscopy in semithin sections of fixed synovial fluid cytocentrifugate. Fragments of synovial membrane were also morphologically analyzed. RESULTS: In the synovial membrane no signs of inflammation were evident either after a single or repeated injections of native Hyaluronan (Hyalgan or Artz). In addition, the cell recruitment and the percentage of cell types in the synovial fluid was not statistically different from saline treated joints. After 3 weekly injections of the crosslinked HA derivative (Hylan G-F20, Synvisc) about 50% of the treated joints appeared slightly inflamed and in these joints a statistically significantly higher cell content was determined in the synovial fluid compared to placebo and native Hyaluronan treatment. In addition an unexpectedly high percentage of eosinophils was found in the synovial fluid and in the synovial membrane of slightly inflamed joints treated with crosslinked HA. CONCLUSION: The data obtained after repeated intra-articular injections in normal rabbit knee joints confirm the safety profile of native Hyaluronan.

Adjuvants, Immunologic↗