Effect of 2,2'-dicarbomethoxylamino-5,5'-dibenzimidazolyl ketone on antioxidant defenses of Acanthocheilonema viteae and its laboratory host Mastomys natalensis

Serum ferritin, alpha-tocopherol, beta-carotene and retinol levels in lymphatic filariasis

Based on a cross-sectional study conducted among 100 adults in 1993 in Tanga, Tanzania, the relationship between Wuchereria bancrofti infection and markers of iron, vitamin A and vitamin E status was assessed. Potential predictors assessed were elephantiasis, hydrocoele, W. bancrofti microfilaria intensity and antigen concentration, and intensity of Schistosoma haematobium, hookworm, Trichuris trichiura and Ascaris lumbricoides infection, while controlling for age, sex and elevated serum alpha-1 antichymotrypsin. Of the 100 adults, 62 had W. bancrofti antigenaemia and 43 microfilaraemia, and 21 had elephantiasis. Of the 64 males, 31 had hydrocoele. W. bancrofti microfilaria intensity was a positive predictor of serum ferritin and a negative predictor of serum alpha-tocopherol. In contrast, negative relationships observed between W. bancrofti microfilaria intensity and serum beta-carotene and retinol were not significant. Neither antigen concentration nor clinical manifestations were predictors of micronutrient status. Intensity of hookworm infection was associated with lower serum ferritin. S. haematobium egg output was not a significant predictor of serum ferritin, but was a positive predictor of serum beta-carotene. In conclusion, W. bancrofti microfilaria intensity was associated with higher serum ferritin, but lower serum alpha-tocopherol. The associations probably reflect increased oxidative stress due to microfilariaehost interactions, which could play a role in the pathogenesis.

Effect of oxygen radicals and differential expression of catalase and superoxide dismutase in adult Heligmosomoides polygyrus during primary infections in mice with differing response phenotypes

The ability of oxygen radicals to kill Heligmosomoides polygyrus adult worms was examined by assessing parasite survival following incubation with hydrogen peroxide and acetaldehyde/xanthine oxidase, generators of H2O2 and H2O2/O2(-), respectively. H. polygyrus worms could tolerate levels of < 0.25 mM hydrogen peroxide and < 0.5 mM/20 mU acetaldehyde/xanthine oxidase for 20 h, but, at higher concentrations, marked sex-dependent susceptibility was observed, with males being more sensitive to H2O2 and O2(-) than female worms. The ability to evade free radical-mediated damage was also evaluated by measuring superoxide dismutase (SOD) and catalase levels in worms isolated at different time points from four strains of mice with differing resistance phenotypes. Levels of both catalase and SOD in female worms isolated from 'rapid'[(SWRxSJL)F1], 'fast' (SWR) or 'intermediate' (BALB/c), but not 'slow' (C57BL/10), responder mice showed a strain-dependent increase with time. Moreover, male worms were rejected faster than female worms in the 'rapid', 'fast' and 'intermediate' responder strains of mice. The results suggest that host-derived free radicals can damage adult worms and that female worms can increase production of their scavenging enzymes in response to the immune onslaught that eventually leads to worm expulsion in mice with 'fast', 'rapid' or 'intermediate' response phenotypes.

Evaluation of free radical status in CSF in childhood meningitis

The study was undertaken to investigate the possible role of free radicals and antioxidants in childhood meningitis. Sixty children suffering from acute bacterial meningitis (ABM) or tuberculous meningitis (TBM) according to their clinical and laboratory findings were enrolled in the study. The production of superoxide anions (O2.-), hydrogen peroxide (H2O2) and malondialdehyde (MDA) and the activities of xanthine oxidase (XO), superoxide dismutase (SOD) and glutathione peroxidase (GPx) were monitored in the study groups and findings compared with those in 20 age-matched controls. Children with ABM and TBM who died registered significant increases in the production of O2.- and MDA and in the activities of SOD and CPK compared with survivors. The rate of production of oxidants and MDA and the activities of XO, SOD and CPK were of a much higher magnitude in deceased ABM and in ABM survivors than in fatal TBM and survivors, respectively. The abnormalities in most of the biochemical parameters investigated were more marked in the children with ABM than in TBM and controls (p < 0.001). Increased MDA production and creatine phosphokinase (CPK) activity of different magnitudes in the two study groups suggest varying degrees of tissue damage. The alterations observed in 20 children who died (14 from ABM, 6 from TBM) revealed elevated levels of oxidants, antioxidants and toxicity markers, particularly in ABM patients, which suggests the possibility that natural or synthetic antioxidants might prevent disease progression and tissue damage in childhood meningitis.