We previously have reported that the mitogen-activated protein kinase (MAPK) pathway is stimulated by adhesion of human chondrocytes to anti-␤ 1 -integrin antibodies or collagen type II in vitro. These mechanisms most likely prevent chondrocyte dedifferentiation to fibroblast-like cells and chondrocyte death. To investigate whether this pathway plays an essential role for the differentiation, phenotype, and survival of chondrocytes, we blocked mitogen-activated protein kinase/extracellular signal-regulated kinase (Erk) (MEK), a kinase upstream of the kinase Erk by using U0126. Exposure of chondrocytes to U0126 caused activation of caspase-3 in a dose-dependent manner. Western blot analysis with an antibody specific for dually phosphorylated Erk shows that collagen type II induced phosphorylation of Erk1/2 was specifically blocked by U0126 in a dose-dependent manner. Immunohistochemical analysis showed that treated chondrocytes were caspase-3 positive. In treated chondrocytes, the cleavage of 116-kDa poly(ADP-ribose)polymerase resulted in the 85-kDa apoptosis-related cleavage fragment and was associated with caspase-3 activity. Analysis by electron microscopy showed typical morphological signs of apoptosis, such as crescent-shaped clumps of heterochromatin, and a degraded pericellular matrix. Thus, these results indicate that the MEK/Erk signal transduction pathway is involved in the maintenance of chondrocytes differentiation and survival. These data stimulate further investigations on the role of mitogen-activated protein kinase pathways in human chondrocytes.Apoptosis, or programmed cell death, plays a key role in embryogenesis, immunological competence and tissue homeostasis for cell removal and can distinguished biochemically and morphologically from cell necrosis, which is a passive, energyindependent form of cell death. Chondrocyte degradation and death occurs in enchondral ossification as well as in age-associated athropathies such as osteoarthritis (1, 2). Chondrocyte apoptosis, can be induced in vitro by a variety of agents, such as nitric oxide, oxygen radical scavengers (3), tumor necrosis factor (4), and interleukin-1␤ (5).It is known that many cell types including chondrocytes require integrin mediated interactions with the extracellular matrix to survive, differentiate, and proliferate (6, 7). Cells undergo a specific cell death or apoptosis in the absence of specific matrix components (8). Interaction between chondrocytes and cartilage matrix components or anti-␤ 1 -integrin antibodies leads to a rearrangement of cytoskeletal and signaling proteins localized at focal adhesions and focal adhesion kinase (6 -9). These stimulate docking proteins such as Src-homology collagen. Src-homology collagen then associates with growth factor receptor-bound protein 2, and extracellular signal-regulated kinase (Erk) 1 (7). These mechanisms most likely prevent chondrocyte dedifferentiation to fibroblast-like cells and chondrocytes death (7)(8)10).It is well known that one of the early reactions occurring in the c...

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We have examined the mechanism by which collagen-binding integrins co-operate with insulin-like growth factor-I (IGF-I) receptors (IGF-IR) to regulate chondrocyte phenotype and differentiation. Adhesion of chondrocytes to anti-beta1 integrin antibodies or collagen type II leads to phosphorylation of cytoskeletal and signalling proteins localized at focal adhesions, including alpha-actinin, vinculin, paxillin and focal adhesion kinase (FAK). These stimulate docking proteins such as Shc (Src-homology collagen). Moreover, exposure of collagen type II-cultured chondrocytes to IGF-I leads to co-immunoprecipitation of Shc protein with the IGF-IR and with beta1, alpha1 and alpha5 integrins, but not with alpha3 integrin. Shc then associates with growth factor receptor-bound protein 2 (Grb2), an adaptor protein and extracellular signal-regulated kinase. The expression of the docking protein Shc occurs only when chondrocytes are bound to collagen type II or integrin antibodies and increases when IGF-I is added, suggesting a collaboration between integrins and growth factors in a common/shared biochemical signalling pathway. Furthermore, these results indicate that focal adhesion assembly may facilitate signalling via Shc, a potential common target for signal integration between integrin and growth-factor signalling regulatory pathways. Thus, the collagen-binding integrins and IGF-IR co-operate to regulate focal adhesion components and these signalling pathways have common targets (Shc-Grb2 complex) in subcellular compartments, thereby linking to the Ras-mitogen-activated protein kinase signalling pathway. These events may play a role during chondrocyte differentiation.

The therapeutic effectiveness of adjuvant therapy with fosfomycin was studied in a prospective clinical trial of 60 patients suffering from chronic post-traumatic osteomyelitis. The patients were aged between 17 and 78 years (mean 37.4 years). The chronic osteomyelitis was predominantly located in the tibia (43 patients) and in the femur (13 patients). Most of the pathogens isolated were Staphylococcus aureus (42%), coagulase-negative staphylococci (19%), Pseudomonas aeruginosa (12%), streptococci (7%) and enterococci (5%). The pathogens isolated from the osteomyelitic foci were sensitive to fosfomycin. Fosfomycin concentrations in bone samples were determined in 19 patients. In the group of patients receiving initially 5 g fosfomycin, bone concentrations ranged between 119.4 and 451.2 mg/l of interstitial fluid. In the group of patients receiving initially 10 g fosfomycin, bone concentrations ranged between 117.1 and 3684.2 mg/l of interstitial fluid. The mean MIC90 values of the isolated pathogens ranged between 2 and 64 mg/l (S. aureus and Escherichia coli 2 mg/l, Proteus vulgaris 8 mg/l, streptococci groups A and B 32 mg/l and coagulase-negative staphylococci, enterococci and P. aeruginosa 64 mg/l). The outcome of treatment was assessed after a minimum of seven and a maximum of 53 months (mean 37 months). The results were: very good 54.7%, good 3.8%, satisfactory 15.1% and unsatisfactory 26.4%.

Every second traumatized patient is a chronic alcoholic. Chronic alcoholics are at risk due to an increased morbidity and mortality. Reliable and precise diagnostic methods for detecting alcoholism are mandatory to prevent posttraumatic complications by adequate prophylaxis. The patient's history, however, is often not reliable, and conventional laboratory markers are not sensitive or specific enough. The aim of this study was to investigate whether carbohydrate-deficient transferrin (CDT) is a sensitive and specific marker to detect alcoholism in traumatized patients. One hundred and five male traumatized patients or their relatives gave their written informed consent to participate in this institutionally approved study. All patients were transferred to the intensive care unit after admission to the emergency room, followed by surgical treatment. Diagnostics included an alcoholism-related questionnaire, conventional laboratory markers (mean corpuscular volume, gamma-glutamyltransferase, aspartate aminotransferase, and alanine aminotransferase), and CDT sampling (microanion-exchange chromatography, turbidimetry, and radioimmunoassay, respectively). Only patients in whom a reliable history could be obtained were included. Alcoholism was diagnosed if the patients met the Diagnostic and Statistical Manual of Mental Disorders criteria for chronic alcohol abuse or dependence. The administration of fluids before CDT sampling was carefully documented. Patients did not differ significantly regarding age, Trauma and Injury Severity Score, and Acute Physiology and Chronic Health Evaluation score. The sensitivity of the CDT research kit was 70% and of the commercially available kit CDTect was 65%. Early sampling in the emergency room and before administration of large volumes of fluid increased the sensitivity to 83% for the CDT research kit and 74% for CDTect, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)