Risk factors associated with hepatocellular carcinoma (HCC) are well documented, but the synergisms between these risk factors are not well examined. We conducted a hospital-based, case-control study among 115 HCC patients and 230 non-liver cancer controls. Cases and controls were pathologically diagnosed at The University of Texas M. D. Anderson Cancer Center and were matched by 5-year age groups, sex, and year of diagnosis. Information on risk factors was collected by personal interview and medical records review. Blood samples were tested for the presence of antibodies to hepatitis C virus antigen (anti-HCV), hepatitis B surface antigen (HBsAg), and antibodies to hepatitis B core antigen (anti-HBc). Conditional logistic regression was used to determine odds ratios (ORs) by the maximum likelihood method. Multivariate ORs and 95% confidence intervals (CIs) were 15.3 (4.3-54.4), 12.6 (2.5-63.1), 4.5 (1.4-14.8), and 4.3 (1.9-9.9) for anti-HCV, HBsAg, heavy alcohol consumption (>80 mL ethanol/d), and diabetes mellitus, respectively. Synergistic interactions on the additive model were observed between heavy alcohol consumption and chronic hepatitis virus infection (OR, 53.9; 95% CI, 7.0-415.7) and diabetes mellitus (OR, 9.9; 95% CI, 2.5-39.3). Independent of the effect of HCV, HBV, and diabetes mellitus, heavy alcohol consumption contributes to the majority of HCC cases (32%), whereas 22%, 16%, and 20% were explained by HCV, HBV, and diabetes mellitus, respectively. In conclusion, the significant synergy between heavy alcohol consumption, hepatitis virus infection, and diabetes mellitus may suggest a common pathway for hepatocarcinogenesis. Exploring the underlying mechanisms for such synergisms may indicate new HCC prevention strategies in highrisk individuals.

Ascites fluid has fibrinolytic activity. Because ascites fluid reenters the systemic circulation via the thoracic duct, via a natural peritoneovenous shunt, ascites fluid warrants serious consideration as a pathological fluid that contributes to the systemic fibrinolytic state found in the majority of our patients with ascites.

The sensitivity of methionine residues to oxidation is a mechanism by which many proteins, including plasma proteinase inhibitors, may be oxidatively inactivated. Much evidence suggests that methionine oxidation and concurrent losses of protein activity not only occur widely in living systems but are physiologic, homeostatic processes. Neutrophils, macrophages and other leukocytes secrete large quantities of powerful oxidants at sites of inflammation and may readily bring about methionine oxidative inactivation of proteins. In particular, oxidation of proteinase inhibitors may favorably alter the proteinase-antiproteinase balance to facilitate tissue remodeling and protection from invading organisms. Leukocyte-mediated inhibitor oxidation also appears to regulate local immunosuppressive activity. Pathophysiologic processes such as emphysema and rheumatoidal disease involve derangements of these homeostatic mechanisms.

SW-480 cells, derived from a primary human colon adenocarcinoma, caused dose-dependent platelet aggregation in heparinized human platelet-rich plasma. SW-480 tumour cell-induced platelet aggregation (TCIPA) was completely inhibited by hirudin (5 U/ml) but unaffected by apyrase (10 U/ml). This TCIPA was also unaffected by cysteine proteinase inhibition with E-64 (10 microM) but was limited by cell pretreatment with phospholipase A2. SW-480 cell suspension caused marked dose-dependent decreases in plasma recalcification times using normal, factor VIII-deficient and factor IX-deficient human plasma. This effect was potentiated with cell lysates but inhibited in intact cells pretreated with sphingosine. SW-480 cell suspension did not affect the recalcification time of factor VII-deficient plasma. Moreover, monoclonal antibody against human tissue factor completely abolished SW-480 TCIPA. Taken together, these data suggest that SW-480 TCIPA arises from SW-480 tissue factor activity expression. Trigramin and rhodostomin, RGD-containing snake venom peptides, which antagonize the binding of fibrinogen to platelet membrane glycogen IIb/IIIa, prevented SW-480 TCIPA. Likewise, synthetic peptide GRGDS as well as monoclonal antibodies against platelet membrane glycoprotein IIb/IIIa and Ib prevent SW-480 TCIPA, which was unaffected by control peptide GRGES. On a molar basis, trigramin (IC50 0.09 microM) and rhodostomin (IC50 0.03 microM) were about 6000 and 18,000 times, respectively, more potent than GRGDS (IC50 0.56 mM).