Zinc and Cholera Reply to Nalin
نویسنده
چکیده
To The Editor—The study by Berni Canani et al. [1] of zinc’s inhibitory effect on cholera toxin (CT)–induced ion secretion in human enterocytes is of interest, but it was not clear from their article whether the authors ever tested the efficacy of zinc given after CT had altered ion transport in their Ussing chamber model. Many substances can block the effects of CT when given before or simultaneously with the toxin [2–4], but most have not proven effective when given after the CT-induced flux changes have become established. If zinc proves ineffective when given after CT-induced changes have already been established, it should not be recommended as therapy for patients with cholera. Studies of zinc salts given in such a sequence are indicated. However, another possibility suggests itself, should zinc prove to have clinical efficacy when given before CT—that of mass prophylactic use of dietary zinc supplements in endemic cholera-affected areas, particularly before or at the onset of outbreaks, which typically are seasonal. The efficacy of zinc prophylaxis would require confirmation that a safe and tolerable dose of an absorbable zinc salt results in the desired effect in a clinical setting, such as human volunteer studies, which have been performed to test cholera vaccines [5]. With regard to inclusion of zinc in oral rehydration solutions (ORSs), this would require clinical demonstration of noninterference by zinc with ORS absorption, since zinc has been reported to interfere with salt and water absorption [6], and, although zinc enhances glucose absorption, it does so without increasing water and sodium absorption [7]. The effects of zinc on other ORS substrates have not been reported.
منابع مشابه
Cholera toxoid boosts serum Escherichia coli antitoxin in humans.
Sera from individuals vaccinated with a cholera toxoid were tested to determine if sera with significant titers of cholera antitoxin could neutralize Escherichia coli thermolabile enterotoxin. Individuals who responded to immunization with significant increases in serum cholera antitoxin titers also showed increases in serum E. coli enterotoxin-neutralizing capacity. These findings suggested th...
متن کاملSuppressive effect of zinc on antibody response to cholera toxin in children given the killed, B subunit-whole cell, oral cholera vaccine.
In a previous study, children aged 2-5 years old in Bangladesh were supplemented orally with a single dose of Vitamin A (200,000 IU) and a placebo for zinc (zinc equivalent to 20 mg of elemental zinc) everyday for 42 days (group A), zinc and a placebo for Vitamin A (group Z), zinc and Vitamin A (group AZ) or both placebos (group P). All children were orally immunised with two doses of the kille...
متن کاملImpact of zinc deficiency on vibrio cholerae enterotoxin-stimulated water and electrolyte transport in animal model.
The effect of zinc deficiency on the function of the intestine to absorb water and electrolytes was studied in animal models, stimulated by Vibrio cholerae enterotoxin. Sprague-Dawley rats, used in the study, were divided into four groups: Zinc-deficient, ad libitum zinc-fed control, zinc weight-matched control, and zinc-deficient acutely-repleted. 14C-labelled polyethylene glycol solution was ...
متن کاملSupplementation with zinc, but not vitamin A, improves seroconversion to vibriocidal antibody in children given an oral cholera vaccine.
To investigate whether micronutrient supplementation could improve the vibriocidal antibody response of children to a killed oral cholera vaccine, 2-5-year-old children were randomly assigned to receive vitamin A and zinc (AZ group), vitamin A and a placebo (A group), zinc and a placebo (Z group), or both placebos (P group). All children received 2 doses of the vaccine. The number of children w...
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تاریخ انتشار 2005