Prevention of catheter-related venous thrombosis with nadroparin in patients receiving chemotherapy for hematologic malignancies: a randomized, placebo-controlled study.

BACKGROUND: Hemato-oncology patients treated with intensive chemotherapy usually require the placement of a central venous catheter (CVC). CVCs are frequently complicated by catheter-related central venous thrombosis (CVT), which has been associated with an increased risk of pulmonary embolism and catheter-related infection. OBJECTIVES: To determine the efficacy and safety of thromboprophylaxis with s.c. low-molecular-weight heparin (nadroparin) administered once daily in a randomized placebo-controlled, double-blind trial in patients with hematologic malignancies. PATIENTS AND METHODS: Consecutive patients with hematologic malignancies requiring intensive chemotherapy including autologous stem cell transplantation were eligible. The patients were randomized to receive nadroparin 2850 antifactor Xa units once daily or placebo s.c. for 3 weeks. Venography was performed on day 21 after CVC insertion. Secondary outcomes were bleeding and catheter-related infection. RESULTS: In total, 113 patients were randomized to nadroparin or placebo, and 87 patients (77%) underwent venography. In total, 11 venographically proven catheter-related CVTs were diagnosed. The frequency of catheter-related CVT was not significantly different between study groups, namely four catheter-related CVTs in the placebo group [9%; 95% CI: 0.002-0.16] vs. seven catheter-related CVTs in the nadroparin group (17%; 95% CI: 0.06-0.28). In addition, no difference in the incidence of catheter-related infection or bleeding was observed between the groups. CONCLUSION: This study showed that the actual risk for catheter-related CVT in patients with hematologic malignancies is lower than suggested in earlier studies in cancer patients. Although prophylactic administration of nadroparin appeared to be safe in this group of patients with a high risk of bleeding, it cannot be recommended for the prevention of catheter-related CVT or catheter-related infection in patients with hematologic malignancies.

Mechanisms of heparin induced anti-cancer activity in experimental cancer models.

BACKGROUND: Retrospective analyses of clinical trials and prospective clinical studies have suggested that heparins may have an effect on cancer survival. This putative anti-cancer activity of heparins is supported by data from studies in animal tumour models. OBJECTIVE: To clarify the various potential mechanisms of heparin anti-cancer activity we evaluated the data from pre-clinical studies in which heparins have been tested as anti-cancer therapy. METHODS: Pre-clinical studies, published between 1960 and 2005 were assessed. Data were collected on the type and dose of heparin used, duration of exposure to heparin, interval between heparin administration and cancer cell inoculation, and the animal tumour model used. In addition, a distinction was made in the analysis between heparin effects on the primary tumour or on established metastases and effects on the metastatic potential of infused cells. RESULTS: Heparins seemed to affect the formation of metastasis rather than the growth of primary tumours. Chemically modified heparins with no or limited anticoagulant activity also showed anti-metastatic properties. Possible mechanisms to explain the effects on the process of metastases include inhibition of blood coagulation, inhibition of cancer cell-platelet and -endothelial interactions by selectin inhibition and inhibition of cell invasion and angiogenesis. CONCLUSION: The anti-cancer activity of heparins depends more on inhibition of metastasis formation than on the effects on primary tumour growth. These effects are probably related to both coagulation and non-coagulation dependent factors. For a definitive proof of the anti-cancer activity of heparins in the clinic, prospective randomized trials especially in patients with early metastatic disease or in the adjuvant setting are urgently needed.

Quantitation of interferon gamma- and interleukin-4-producing T cells in synovial fluid and peripheral blood of arthritis patients.

OBJECTIVE: The balance between T cells able to produce interferon gamma (IFN-gamma) (type 1) and interleukin-4 (IL-4) (type 2) is considered to be important in the development of autoimmunity. In this study, we quantitated the percentage of both cell types in synovial fluid (SF) and peripheral blood (PB) of rheumatoid arthritis (RA) patients, non-rheumatoid arthritis patients and healthy controls. METHODS: After short-term stimulation of synovial mononuclear cells with phorbol ester and ionomycin, cytokine-producing cells were quantitated using an intracellular staining technique and flow cytometric analysis. RESULTS: Although no significant differences in CD8 + cells were found, significantly higher percentages of IFN-gamma-producing CD4 + (Th 1) and IL-4-producing CD4 + (Th2) cells were found in the peripheral blood of RA patients in comparison with healthy controls. However, the Th1/Th2 ratio was not different between the two groups. Comparative studies between PB and SF showed that in both RA and non-RA patients, percentages of Th1 cells were higher in SF than in PB, while Th2 cells were preferentially found in the PB, resulting in a higher Th1/Th2 ratio in the SF. The Th1/Th2 ratio in the SF correlated with disease activity as estimated by the erythrocyte sedimentation rate. CONCLUSION: These results are in agreement with the hypothesis that Th1 cells preferentially home to inflamed joints in both RA and non-RA patients, but show that this does not result in an altered Th1/Th2 ratio in the PB of RA patients.