Philippe Gysen

Tumor necrosis factor and interleukin-1 serum levels during severe sepsis in humans.

In a study of serum levels of tumor necrosis factor (TNF alpha) and interleukin-1 beta (IL-1 beta) in patients developing sepsis in the ICU, high TNF alpha levels were found in patients with septic shock. Normal values are 75 +/- 15 pg/ml; in these patients, TNF alpha serum level ranged from 100 to 5000 pg/ml with a mean of 701 +/- 339 pg/ml and a median of 250 pg/ml. There was a correlation between TNF alpha level and sepsis severity score as well as with mortality. In contrast, IL-1 beta serum levels were only slightly increased and were not correlated with severity or mortality.

Effects of peptidic glycosaminoglycans complex on human chondrocytes cultivated in three dimensions

Human chondrocytes from the pelvic joint were cultivated in suspension; under these conditions, after a few days, cells aggregated. These chondrocytes were morphologically differentiated (round shape, situated inside cavities and surrounded by a matrix synthesized during cultivation) and biosynthetically differentiated (synthesis of type II collagen and cartilage proteoglycans (PG) (Bassleer et al. In vitro 22, 115-120, 1986). In this work, we present the metabolic and cellular effects of a peptidic-glycosaminoglycan (P-GAG) complex isolated from calf cartilage and bone marrow. We analyzed the effects of P-GAG on DNA synthesis (appreciated by 3H-thymidine incorporation into DNA), on type II collagen and on PG synthesis analyzed by specific radioimmunoassays. According to its final concentration in culture medium, P-GAG was able to stimulate proliferation or to favor the production of specific components of cartilage matrix, type II collagen and PG.

Proteoglycans synthesized by human chondrocytes cultivated in clusters

Proteoglycan metabolism was studied by a specific human cartilage proteoglycan radioimmunoassay in human chondrocytes cultivated in clusters. In this culture system, after a few days, previously dissociated chondrocytes were aggregated. They then synthesized a new cartilage matrix and were morphologically differentiated; they had a round shape and were situated inside small individual cavities (lacunae). The amounts of proteoglycan released into culture medium and present in chondrocyte clusters were maximal on the third to fifth day of culture; production decreased and stabilized from the 10th day to the end of culture. During the first days of culture, monomeric proteoglycans were present in large proportion; they gradually decreased between the sixth and 11th day of culture. These results suggest a modified synthesis of proteoglycan and hyaluronic acid during cultivation.

Characterization of proteoglycans produced by human chondrocytes cultivated in clusters

After enzymatic dissociation from their matrix, human chondrocytes from hip joint were cultivated in suspension, in flasks containing 2 ml of Dulbeccos Modification of Eagles Medium (Flow) supplemented with 10% foetal calf serum (Gibco). Flasks were disposed on a gyrotory shaker (100 rpm) at 37~ [1]. After a few days, cells aggregated and secreted a new intercellular matrix composed of type II collagen and cartilage proteoglycans (PG) [1]. Using a specific human cartilage PG radioimmunoassay [2], we analyzed PG produced by human chondrocytes in dusters.