Association between serum carcinoembryonic antigen and endothelial cell adhesion molecules in colorectal cancer

OBJECTIVES: To analyse the behaviour of pre-surgical serum levels of soluble (s)E-selectin and vascular cell adhesion molecule (sVCAM) in patients with colorectal cancer, and to evaluate their possible correlation with carcinoembryonic antigen (CEA), pro-inflammatory cytokines and clinicopathological features with respect to their prognostic value in predicting metastatic disease. METHODS: Pre-surgical serum levels of sE-selectin, sVCAM, interleukin-6 (IL-6), IL-1beta, tumour necrosis factor-alpha (TNF-alpha) and CEA were measured in 194 patients with colorectal adenocarcinoma, 40 patients with benign colorectal diseases and 59 healthy subjects. RESULTS: sE-selectin, sVCAM, TNF-alpha and IL-6 levels were significantly higher in patients with colorectal cancer compared to either healthy subjects or patients with benign disease. Positive rates of sE-selectin, sVCAM and TNF-alpha levels were significantly associated with Dukes' stage D colorectal cancer, and all three variables were independently associated to the presence of distant metastases. Positive sE-selectin, sVCAM and TNF-alpha levels were significantly associated to CEA. TNF-alpha and CEA levels were independently related to the presence of positive levels of sE-selectin and/or sVCAM. CONCLUSIONS: Our findings suggest that the host inflammatory response to cancer cells, and/or their released products (i.e. CEA), might be responsible (via cytokine release) for the elevation in circulating adhesion molecules in patients with colorectal cancer

Shape change is independent of tyrosine phosphorylation of p130 in human platelets

It has been previously suggested that tyrosine phosphorylation of p62, p68, and p130 might be necessary for the platelet shape change to occur. In preliminary studies we observed that high concentrations (30 mu M) of a protein kinase C inhibitor, Ro 31-8220, selectively suppressed p130 tyrosine phosphorylation induced by thrombin, the thromboxane synthetic analogue (U46619) and ADP. Therefore, we have investigated the correlation, if any, between p130 tyrosine phosphorylation and platelet shape change induced by the same agonists in the presence of Ro 31-8220. Our results demonstrated that high concentrations of this compound almost completely abolished p130 tyrosine phosphorylation, whereas they had no effect on platelet shape change, thus proving a dissociation between these two phenomena. Our data support the hypothesis that a role in platelet shape change might be played by tyrosine phosphorylation of proteins other than p130. (C) 1998 Elsevier Science Ltd

Rebuttal to circulating IL-6 levels in chronic obstructive pulmonary disease

[No abstract available

Evidence for separate effects of U73122 on phospholipase C and calcium channels in human platelets

U73122 ({1-[6-((17 beta-3-methoxyestra-1,3,5(10)-trien-17-yl)amino)exyl]-1H-pyrrole-2,5-dione}) is generally used as a selective inhibitor of phospholipase C (PLC) and the related rise in cytosolic Ca2+. Recently, by using hepatocytes, it was suggested that its action sites are different for PLC activation and increase in Ca2+ concentration. To verify whether U73122 has different sites for inhibiting PLC activation and calcium responses in human platelets, aggregation, Mn2+ influx, cytosolic Ca2+ increase and PLC activation were studied in response to thrombin and the synthetic agonist of the thromboxane receptor U46619 (9,11-dideoxy-9 alpha,11 alpha-methanoepoxyprostaglandin F-2 alpha). With both agonists, U73122 inhibited aggregation, Mn2+ influx and the enhancement of cytosolic calcium at concentrations of 2 mu M or lower, while 10 mu M was necessary to inhibit PLC activation. Our results suggested that U73122 is much more active in antagonizing Ca2+ channels, both the intracellular ones, which are activated by formation of inositol 1,4,5 P-3 and those present on plasma membrane, than in reducing the activation of PLC. BIOCHEM PHARMACOL 56;11:1481-1484, 1998. (C) 1998 Elsevier Science Inc

Replay to: Lipoprotein (a) and chronic obstructive pulmonary disease.

Lettera di risposta ad alcune osservazioni sull'articolo pubblicato su Atherosclerosis 1999, 147(2); 249-25

Vitamin E inhibits collagen-induced platelet activation by blunting hydrogen peroxide

In this study, we investigated whether vitamin E at concentrations achievable in blood after supplementation inhibits platelet function in humans. Gel-filtered platelets were incubated 30 minutes with scalar concentrations (50 to 250 mmol/L) of vitamin E and then stimulated with collagen. Compared with controls, vitamin E inhibited collagen-induced platelet aggregation and thromboxane A2 formation in a dose-dependent manner. Furthermore, vitamin E inhibited, in a dose-dependent manner, Ca2+ mobilization and formation of inositol 1,4,5-triphosphate, Because it was previously shown that hydrogen peroxide formation mediates arachidonic acid metabolism and phospholipase C activation in collagen-induced platelet activation, we investigated whether vitamin E was able to blunt hydrogen peroxide. In experiments performed in unstimulated platelets supplemented with hydrogen peroxide and in collagen-stimulated platelets, vitamin E was able to blunt hydrogen peroxide. In 6 healthy subjects given vitamin E for 2 weeks.(600 mg/d), we found a significant decrease of collagen-induced H2O2 formation, platelet aggregation, and calcium mobilization. This study demonstrated in vitro and ex vivo that vitamin E inhibits collagen-induced platelet activation by blunting hydrogen peroxide formation

Hydrogen peroxide is involved in collagen-induced platelet activation

In this study, we investigated whether (1) collagen-induced platelet aggregation is associated with a burst of H2O2, (2) this oxidant species is involved in the activation of platelets, and (3) the pathways of platelet activation are stimulated by H2O2 Collagen-induced platelet aggregation was associated with production of H2O2, which was abolished by catalase, an enzyme that destroys H2O2. H2O2 production was not observed when ADP or thrombin were used as agonists. Catalase inhibited dose-dependently thromboxane A(2) production, release of arachidonic acid from platelet membrane, and Inositol 1,4,5P(3) (IP3) formation. In aspirin-treated platelets stimulated with high concentrations of collagen, catalase inhibited platelet aggregation, calcium mobilization, and IP3 production. This study suggests that collagen-induced platelet aggregation is associated with a burst of H2O2 that acts as a second messenger by stimulating the arachidonic acid metabolism and phospholipase C pathway. (C) 1998 by The American Society of Hematology