In Vitro Cysteine Reactivates Organophosphate Insecticide Dichlorvos-Inhibited Human Cholinesterases.

OBJECTIVES: Organophosphate (OP) pesticides inhibit both red blood cell (RBC) and plasma cholinesterases (ChEs). Oximes, especially pralidoxime (2-PAM), are widely used as antidotes to treat OP poisoning. In addition, N-acetylcysteine (NAC) is sometimes used as an adjuvant antidote. The current study aimed to assess the feasibility of using NAC as a single therapeutic agent for OP poisoning in comparison to in vitro 2-PAM. METHODS: This study was carried out at the Razi Drug Research Center of Iran University of Medical Sciences, Tehran, Iran, between April and September 2014. A total of 22 healthy human subjects were recruited and 8 mL citrated blood samples were drawn from each subject. Dichlorvos-inhibited blood samples were separately exposed to low and high doses (final concentrations of 300 and 600 µmol.L-1, respectively) of 2-PAM, NAC and cysteine. Plasma and RBCs were then separated by centrifugation and their ChE activity was measured using spectrophotometry. RESULTS: Although cysteine-and not NAC-increased the ChE activity of both plasma and RBCs over those of dichlorvos, it did not increase them over those of a high dose of 2-PAM. CONCLUSION: These results suggest that the direct reactions of 2-PAM and cysteine with dichlorvos and the reactivation of phosphorylated ChEs occurr via an associative stepwise addition-elimination process. High therapeutic blood concentrations of cysteine are needed for the elevation of ChE activity in plasma and RBCs; however, both this agent and NAC may still be effective in the reactivation of plasma and RBC ChEs.

A randomised controlled trial of oral zinc sulphate for primary dysmenorrhoea in adolescent females.

BACKGROUND: Primary dysmenorrhoea, the most common gynaecologic problem of adolescent females, is commonly treated with nonsteroidal anti-inflammatory drugs or oral contraceptive pills. AIM: To compare the effect of zinc sulphate with that of placebo on the control of pain severity and duration in adolescent girls with primary dysmenorrhoea. MATERIALS AND METHODS: In a three-month randomised double-blind placebo-controlled clinical trial, 120 adolescent females with primary dysmenorrhoea were randomly divided into two groups of sixty: an intervention group (zinc) and a control group (placebo). Zinc was administered in the form of a capsule containing 50 mg/day zinc sulphate beginning on the first day of menses and continuing until three days prior to the end of menses. Each month, the duration and severity of primary dysmenorrhoea were determined. Severity scoring was performed by using a 0-10 scaling system. RESULTS: In the first month, the duration of pain was significantly lower in the zinc group compared with the placebo group (P-value = 0.044), while there was no significant difference in pain severity between the groups (P-value = 0.497). In the second and third month, pain severity and duration in the zinc group were significantly lower than the placebo group (P-value <0.001). CONCLUSION: Both pain duration and pain severity were decreased by taking oral zinc. The results of our interventional study suggests that zinc may be used to treat primary dysmenorrhoea in adolescents.