Marginal zinc deficiency exacerbates experimental colitis induced by dextran sulfate sodium in rats

We investigated the impact of Zn status on the maintenance of mucosal homeostasis. Rats were fed diets containing different amounts of Zn (30, 10, 5, <1 mg Zn/kg diet) for 21 d. Serum Zn concentrations were lower in rats fed marginally Zn-deficient (MZD; 5 mg Zn/kg diet) and severely Zn-deficient (<1 mg/kg) diets but not in those fed the marginally Zn-adequate diet (10 mg/kg) or the Zn-adequate (ZA; 30 mg/kg) group (P < 0.05). However, organ weights, colonic epithelial cell proliferation, and crypt fission did not differ between the MZD and ZA groups. We then evaluated whether MZD modulated dextran sulfate sodium (DSS)-induced colonic inflammation by administering 2% DSS to the MZD and ZA groups for 7 d. Myeloperoxidase activity and TNFα production increased in response to DSS in the MZD group (P < 0.03). Colonic permeability in the 2 groups did not differ after DSS administration. In a culture experiment using isolated mesenteric leukocytes, TNFα production was higher (P < 0.05) and TNF receptor type I (TNFR1) expression was detected in culture medium containing 20 and 30 μmol/L of Zn compared with culture medium lacking Zn supplementation. These results suggest that MZD exacerbated colitis by modulating the immune response through the impairment of TNFα production and TNFR1 expression rather than through the impairment of epithelial barrier function.

The anticardiolipin antibody in elderly stroke patients: its effects on stroke types, recurrence, and the coagulation-fibrinolysis system

Anticardiolipin antibody (aCL) is known as a risk marker for stroke, particularly in subjects younger than 50 years of age. We studied the effects of aCL on stroke types, recurrences, and the coagulation-fibrinolysis system in 257 elderly patients (63.2 +/- 11.4 years). Follow-up was performed for 3.1 years on 184 patients, for whom the rate of symptomatic and asymptomatic reinfarcts on CT was studied. aCL was positive in 30 (12%) of the patients. The incidence of atherosclerotic changes in the cerebral arteries was not significantly different between aCL-positive and aCL-negative patients. The aCL-positive patients had a greater rate of individuals not having any of the known risk factors (p < 0.05), a greater incidence of cortical infarctions (p < 0.05), more frequent symptomatic recurrences (p < 0.05). They had significantly greater changes in molecular markers for the coagulation-fibrinolysis system in the acute phase (p < 0.05), but not in the chronic phase.

Effect of plasma fibrinogen concentration on the inhibition of platelet aggregation after ticlopidine compared with aspirin

BACKGROUND AND PURPOSE

Elevated levels of plasma fibrinogen are a risk factor for cerebral infarction. Because fibrinogen plays a central role in platelet aggregation and binding of fibrinogen to platelets is inhibited by ticlopidine, we studied the effect of the plasma fibrinogen concentration on the antiaggregatory action of ticlopidine compared with that of aspirin.

METHODS

We determined platelet aggregability before and after administration of ticlopidine (200 mg/d) or aspirin (81 mg/d) in 61 stroke patients and correlated the changes with the plasma fibrinogen concentration.

RESULTS

In patients receiving ticlopidine, the platelet aggregability induced by 1, 5, and 10 mumol/L adenosine diphosphate significantly decreased compared with aggregability before medication (P < .05), and the reductions had significant negative correlations with the plasma fibrinogen concentration (P < .05). In patients receiving aspirin, the platelet aggregability induced by 2 micrograms/mL collagen and 5 and 10 mumol/L adenosine diphosphate decreased compared with aggregability before medication (P < .005), but the reductions had no significant correlation with the plasma fibrinogen concentration.

CONCLUSIONS

The relative antiaggregatory effect of ticlopidine is significantly decreased with higher plasma fibrinogen concentrations. This may explain, at least in part, the individual variation in the response to ticlopidine.