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Journal of the American College of Nutrition, Vol. 21, No. 1, 26-32 (2002)
Published by the American College of Nutrition

Original Research

Zinc Supplementation in Oral Rehydration Solutions: Experimental Assessment and Mechanisms of Action

Waseem Altaf, MD, Shahana Perveen, MD, Khalil U. Rehman, MD, Saul Teichberg, PhD, Ivana Vancurova, PhD, Rita G. Harper, MD, FACN and Raul A. Wapnir, PhD, FACN, CNS

Department of Pediatrics, Division of Neonatal/Perinatal Medicine, North Shore-Long Island Jewish Health System, Manhasset, New York

Address correspondence to: Raul A. Wapnir, PhD, FACN, CNS, Department of Pediatrics, North Shore University Hospital, Manhasset, New York 11030. E-mail: rwapnir{at}nshs.edu.


   ABSTRACT
TOP
 ABSTRACT
INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
 ACKNOWLEDGMENTS
 REFERENCES
 
Background: Zinc deficiency is associated with chronic diarrhea. This condition is generally linked to an overproduction of nitric oxide (NO), which induces secretion and cellular damage as a free radical. Use of oral rehydration solutions (ORS) is an important part of diarrhea treatment, especially early in infancy and for patients with cholera. The presence of zinc in an ORS could be a positive factor in recovery from diarrheal disease.

Objective: This study was undertaken to determine whether zinc added to an ORS could regulate the synthesis of NO metabolites in the lumen of zinc deficient rat intestine, acting as a gastrointestinal protector and thus accelerating normalization of intestinal function and zinc status.

Methods: The effects of zinc on NO metabolism were studied in young male rats fed a zinc deficient diet for three weeks to mimic the condition of patients with recurrent diarrheal episodes. During the fourth week of the zinc deficient feedings, experimental diarrhea was induced using cathartics (magnesium citrate plus phenolphthalein) that exacerbate NO production. A standard ORS with or without 1 mM zinc was given to the rats for the last two days. A control group received a zinc sufficient diet. Rats were killed at each stage. Intestinal nitric oxide synthase (NOS) was assayed, cecal fluid contents were analyzed for nitrates and nitrites, intestinal histology was examined, and activation of nuclear factor NF-{kappa}B DNA binding activity was determined.

Results: Rats fed the zinc-deficient diet for three weeks gained less weight than rats fed a normal zinc content diet and had a lower plasma zinc than controls (51.6 ± 5.4 [n = 10] vs. 143.6 ± 7.2 µg/dL [n = 11], p < 0.05). Recovery with ORS+Zn resulted in a higher plasma zinc than with the ORS-Zn (ORS+Zn: 186.5 ± 12.2; ORS-Zn: 57.5 ± 6.6 µg/dL, p < 0.05). The zinc-deficient diet did not alter mucosal NOS, as compared to the values of rats fed a normal diet. However, those animals which received five days of cathartic fluids had a small intestinal NOS higher than that of all other groups. Either ORS+Zn or ORS-Zn normalized NOS activity, regardless of cathartic treatment. The rats fed the zinc deficient diet had generally a higher content of NO metabolites in the cecum than rats fed a normal diet. After recovery with either type of ORS, rats given the cathartic remained with higher cecal NO metabolite concentrations than rats that had no induced diarrhea. After recovery with ORS+Zn, intestinal villi showed significant expansion of the lamina propria, an indication of greater absorption of fluid, while with ORS-Zn this was not present. Small intestinal homogenates of rats recovering with ORS+Zn had a decreased NF-{kappa}B DNA binding activity than tissues from rats consuming ORS-Zn.

Conclusions: The results are consistent with the hypothesis that addition of Zn to an ORS may contribute to improving the physiologic status of the small intestine and potentially reduce the risks of recurrent diarrhea episodes.

Key words: zinc, diarrhea, oral rehydration solutions, nitric oxide, nuclear factor {kappa}B


   INTRODUCTION
TOP
 ABSTRACT
 INTRODUCTION
MATERIALS AND METHODS
 RESULTS
 ACKNOWLEDGMENTS
 REFERENCES
 
Dietary deficiency of some micronutrients has been shown to increase the susceptibility of infants and children to gastrointestinal infections and to have direct adverse effects on gastrointestinal tract structure and function [1–6]. In particular, zinc is relevant as an essential component of some 300 enzymes involved in various metabolic pathways [7,8]. Zinc also plays an important role in intestinal structure and function. In zinc deprived animals, the secretory response to cholera toxin is enhanced and this phenomenon is reversible by dietary replenishment with zinc [1,5]. In addition, zinc has antioxidant and sulfhydryl group protective properties due to its affinity for active sites where redox active metals may generate free radicals, its ability to maintain both superoxide dismutase activity and the higher order structure of proteins [9]. Cytokines responsible for induction of acute phase reactants, such as IL-1, upregulate metallothionein (MT) mRNA expression [10] and, when injected, produce diarrhea in zinc deficient rats but not in well-fed animals [11]. These findings may explain the susceptibility of individuals with compromised zinc status to infectious diarrhea. Infants and children with diarrhea, especially if growth stunted, show a reduction in severity and duration of the disease when supplemented with zinc [3,5]. A self-perpetuating situation may develop where chronic zinc deficiency fosters malabsorptive conditions which, in turn, impair the replenishment of zinc stores, even when sufficient zinc is present in the diet. However, the mechanisms by which zinc may act as an enteroprotective have not yet been determined.

Nitric oxide has multiple physiologic roles in the gastrointestinal tract, including the activation of cGMP synthesis, a second messenger involved in sodium and chloride transport [12,13]. Cyclic GMP production is also elicited by V. cholerae and E. coli enterotoxins, and thus produces a chain of events ultimately resulting in secretory conditions in the small intestine. Common cathartics, such as magnesium salts and phenolphthalein, act by triggering the release of NO [14]. Therefore they are appropriate models for the effects of enterotoxins such as those of V. cholerae and E. coli. It is now well established that the triggering mechanism for synthesis of NO is the activation of the nuclear factor kappa B (NF-{kappa}B) [15,16].

The overall goal of this study was to determine whether zinc added to an oral rehydration solution (ORS) regulates NOS activity and consequently the presence of NO metabolites in the intestinal lumen. The use of zinc deficient rats, and a subgroup with experimental diarrhea, was designed to better demonstrate such relationship. This may clarify the links between zinc nutritional status, susceptibility to chronic diarrhea and potential accelerated recovery with a zinc-enriched ORS.


   MATERIALS AND METHODS
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
RESULTS
 ACKNOWLEDGMENTS
 REFERENCES
 
Induction of Zinc Deficiency
This was achieved by feeding 80–100 g male Sprague-Dawley rats (Taconic, Germantown, NY) a low zinc diet (Dyets, Inc., <3 mg/kg) ad libitum for three weeks. Other rats were given a diet with the same composition, but with sufficient zinc (30 mg/kg) to serve as controls for the determination of the effects of zinc restriction. The remaining ingredients were those recommended by the AIN for optimal growth of rodents [17]. Control diet fed rats were approximately weight matched to the zinc deficient rats by the end of the dietary induction period by using rats of initially smaller size. At the end of the induction period, some of the zinc deficient and control rats were killed.

Induction of Diarrhea and Recovery
Diarrhea was induced during the fourth week by providing for five days a magnesium citrate solution (USP diluted 1:1 with water, supplemented with 100 mg/L phenolphthalein) as the sole source of fluids with the same zinc deficient diet. Other zinc deficient rats were offered distilled water during five days. This protocol has been implemented in other studies [18,19]. At the completion of this period, some rats were killed, and similarly fed ones were given, in addition, a standard ORS (90 mM Na; 20 mM K; 80 mM Cl; 10 mM citrate; 111 mM glucose) ad libitum for 2 days, with or without 1 mM zinc acetate. Weights were monitored weekly during the study. At the completion of the recovery stage with either ORS the remaining rats were killed. Cecal contents were analyzed for nitrites and nitrates. The number of animals studied at each stage is described in tables and figure legends.

Tissue Preparations
For NOS determination, rats were euthanized by exsanguination from the abdominal aorta under urethane anesthesia (1.3 g/kg i.p.). A segment of 20–25 cm of jejunum was removed immediately, flushed with ice-cold normal saline and the whole tissue homogenized in five volumes of a buffer containing 50 mM Tris-HCl pH 7.5; 1 mM EDTA; 1 mM dithiothreitol (DTT); 0.1 mM phenylmethylsulfonyl fluoride (PMSF) and 10 µg/mL each of the protease inhibitors antipain, leupeptin and pepstatin A. Homogenates were spun down at 10,000g for 15 minutes at 4°C and maintained at -70°C until use.

For histology and electron microscopy, 1-cm specimens from the jejunum were quickly excised after laparotomy, fixed in buffered 2% glutaraldehyde, 2% paraformaldehyde, rinsed, post-fixed in 2% buffered osmium tetroxide, dehydrated in a sequence of ethanols and embedded in effapoxy resin. Sections were stained with toluidine blue and examined under a 160x magnification. Thin sections were processed for electron microscopy and examined with a transmission instrument (JEOL-JEM 100CXII) [19].

NOS Assay
For NOS activity, 0.4 mL of sample homogenate was added to a reaction tube containing 1.0 mL incubation buffer (250 mM HEPES; 10 µM CaCl2; 10 µM FAD; 0.5 mM NADPH and 10 µM tetrahydrobiopterin pH 7.4). One mM L-valine was added to all reaction mixtures to inhibit the production of citrulline via the urea cycle. L-arginine with tracer amounts of L-[14C(U)]-arginine (DuPont NEN, Boston MA) at a final concentration of 2 mM was used to initiate the enzymatic reaction. Reaction tubes were incubated in a water bath at 37°C for 60 minutes. After one hour, 2.0 mL of quench buffer (100 mM acetic acid; 10 mM EGTA, pH 5.5) was added to stop the reaction. The entire mixture was then passed through a 1.5 mL Dowex AG50WX-8 column to retain unreacted L-arginine and elute the radiolabeled L-citrulline, which was then washed through with an equal volume of water. To assess nonspecific formation of L-citrulline in the sample, 2 mL of quench buffer was added immediately prior to addition of L-arginine. These values were subtracted from the radioactivity of the effluent, measured with a liquid scintillation counter (Packard, Boston, MA). This difference was taken to calculate NOS activity in the sample, both constitutive and inducible, and expressed in terms of its protein content [20].

Nitrite and Nitrate Assay
For the determination of nitrite assay cecal contents were obtained after killing the rats, weighed and diluted to 5 or 10 mL with distilled water and shaken well. The suspension was centrifuged for 15 min at 10,000g. The supernatant was stored at 4°C. For the determination of nitrite, 0.1 to 0.2 mL of centrifuged cecal fluid sample obtained from each rat was transferred to a 10 x 75 mm tube, water was added to make 1.4 mL, and then 0.075 mL of 14 mM, 4-4'-diamino-diphenyl sulphone (dapsone) in 2 N HCl was added, mixed again, and followed by 0.075 mL of 4 mM naphthylethylene diamine in water. The reaction was read at 540 nm in a spectrophotometer (Spectronic model 21D, Rochester, NY). Nitrite concentration in the samples was calculated from a regression curve of standards containing 1 to 10 nmoles of nitrite [21].

Nitrate determination was performed by reduction of nitrate to nitrite with copperized cadmium. A nitrate standard (100 µM) was similarly treated. Aliquots containing 1 to 10 nmoles of nitrate simultaneously reduced with the samples were assayed for nitrite as indicated above [21].

Preparation of Nuclear Extracts for NF-{kappa}B
Immediately after rats were killed, a 10–15 cm segment of the distal jejunum was excised, rinsed as above, slit open and the mucosa scraped with a glass slide. The mucosa obtained was suspended in 1 mL of cold homogenization fluid, rapidly vortexed and disaggregated, and spun down for 10 minutes at 600 g at 4°C. The supernatant was discarded, and the washed mucosa suspended in 0.75 mL of a hypotonic buffer (10 mM HEPES pH 7.5, 10 mM KCl, 3 mM MgCl2, 1 mM EDTA, 1 mM EGTA, 2 mM DTT, 2 mM PMSF) also containing a protease inhibitor cocktail [22] and placed in ice for 15 minutes. After addition of 0.1 mL 10% Nonidet P-40, the suspension was vortexed and centrifuged at 600g for 15 minutes at 4°C. Following a washing of the pellet under similar conditions, cells were suspended in 0.5 mL of ice-cold nuclear buffer (20 mM HEPES pH 7.5, 25% glycerol, 500 mM KCl, 1 mM MgCl2, 1% Nonidet P-40, 1 mM EDTA, 2 mM DTT and 2 mM PMSF). After 20 minute’s incubation on ice, the suspension was centrifuged at 14,000 g for 15 minutes at 4°C and aliquots stored at -70°C for determination of NF-{kappa}B DNA binding activity by electrophoretic mobility shift assay (EMSA) [22]. The oligonucleotide used as a probe for EMSA was a 42-bp double stranded construct (5'-TTGTTACAAGGGGACTTTCCGCTGGGGACTTTCCAGGGAGGC-3') containing two tandemly repeated NF-{kappa}B binding sites (underlined). Mutant oligonucleotide used for competition studies was 5'-TTGTTACAATCTCACTTTCC-GCTTCTCACTTTCCAGGGAGGC-3'. End labeling was accomplished by treatment with T4 kinase in the presence of {gamma}-[32P]ATP, and the labeled oligonucleotide was purified on a Sephadex G-25 column.

Nuclear extracts containing 4–6 µg of protein in 5–7 µL were incubated for 20 minutes at room temperature with 5–10 fmol of radiolabeled oligonucleotide (approximately 70,000 cpm) in 20 µL of binding buffer (20 mM Tris-HCl pH 7.5, 150 mM KCl, 1 mM EDTA, 1 mM DTT, 0.1% Nonidet P-40, 6% glycerol) supplemented with 20 µg acetylated bovine serum albumin and 2 µg poly(dI-dC). For competition experiments, binding reactions were performed in the presence of 30-molar excess of unlabeled oligonucleotide and incubated 15 minutes at room temperature before adding 32P-labeled oligonucleotide. The resulting complexes were resolved on 5% non-denaturing polyacrylamide gels that had been pre-run at 100 V for 30 minutes in half-strength Tris-borate buffer pH 8.0. Electrophoresis was conducted at 180 V for 2.5 hours. After electrophoresis, gels were transferred to Whatman DE-81 paper, dried and exposed to autoradiographic film (Kodak Biomax BS) with intensifier screen at -80°C. Unless otherwise indicated, reagents were obtained from Sigma Chem. Co. (St. Louis, MO).

Statistical Analysis
Data are presented as means ± SEM and analyzed by a one way analysis of variance followed by a post hoc Tukey’s test for specific critical differences [23] using SAS® and Sigmastat®. For data not normally distributed, the Kruskal-Wallis and Dunn’s tests were applied.


   RESULTS
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
ACKNOWLEDGMENTS
 REFERENCES
 
Growth as Affected by Zinc Deficiency and Diarrhea
During the zinc deficiency induction phase of three weeks, the rats continued to gain weight moderately; however, the weight gain was less than the weight gain by rats fed a normal, zinc-sufficient diet (Table 1). During the cathartic treatment phase for five days, the zinc-deficient rats lost weight, but the zinc-sufficient animals maintained their weight. The rats not given cathartics but fed the zinc deficient diet continued to gain weight. Zinc-sufficient rats were not evaluated in this study beyond the cathartic treatment, as the features of this model have been described earlier [18].


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  		Table 1. Weight Changes during Feedings of Two Types of Zinc Diets, Cathartic-Induced Diarrhea and Two-Day Recovery with Oral Rehydration Solution (ORS) ± Zinc

 
During the recovery from diarrhea the zinc-deficient rats which received ORS-zinc gained more weight than those which received plain ORS (ORS-zinc). The zinc deficient rats which were given no cathartic treatment gained very little weight during this stage, when offered ORS-zinc, but there was a significant weight gain in rats which received ORS+zinc during the same period (Table 1). This weight improvement was similar to that of the rats not exposed to the cathartic.

Physiological Changes Associated with Zinc Deficiency and Diarrhea
Plasma zinc concentration of rats placed on zinc deficient diet for three weeks was significantly lower than the initial values, a finding consistent with depletion of their zinc stores (Table 2). After five days of cathartic treatment, there was a moderate increase in plasma zinc level; however, that could be attributed to dehydration as suggested by a concurrent increased plasma albumin concentration over the data preceding the introduction of the cathartic.


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  		Table 2. Plasma Zinc and Albumin of Zinc Deficient Rats during the Course of the Experiments

 
During the two-day recovery phase, the rats offered ORS-zinc remained zinc depleted, while those which received ORS+zinc returned to their initial plasma zinc levels. Rehydration was apparently accomplished, as suggested by normalization of plasma albumin. After recovering from diarrhea with either ORS+zinc or ORS-zinc, plasma albumin returned to initial values.

Effects on Small Intestinal Mucosal NOS
The zinc-deficient diet did not alter mucosal NOS, as compared to the values of rats fed a normal diet (Fig. 1). However, those animals which received five days of cathartic treatment had a mucosal NOS higher than that of all other groups. After receiving the ORS, either with or without zinc, the enzyme activity was normalized, regardless of whether the animals had been treated with cathartic or not. In addition, there were no differences between the rats that were given ORS+zinc from those which were offered ORS-zinc.



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  		Fig. 1. NOS activity obtained from intestinal homogenates of rats fed either a normal, zinc-sufficient diet; a zinc-deficient diet for three weeks, prior to and after being given five days of cathartic solution; after cathartic treatment and recovery with ORS without zinc (-Zn) or with 1 mM zinc (+Zn); and zinc-deficient rats not exposed to cathartic, but given either ORS for two days. The error brackets indicate the SEM. The number of animals is that of Tables 1 and 2. {dagger} Indicates a significant difference (p < 0.05) respect of all other groups.

 
Cecal Nitrate plus Nitrite Content
The rats fed the zinc deficient diet had generally a higher content of these NO metabolites (Fig. 2). Following zinc depletion and cathartic treatment, these rats had much higher nitrate and nitrite levels than those rats fed a normal diet. After recovery with either type of ORS, rats which were given the cathartic remained with higher NO metabolite concentrations than rats which got ORS, but which did not have induced diarrhea.



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  		Fig. 2. Cecal nitrate plus nitrite content of the treatment groups described for Fig. 1. {dagger} Indicates a significant difference (p < 0.05) in respect to all other groups. * Denotes p < 0.05 between the cathartic-treated and not treated rats, after recovery with ORS, combining the results of those animals consuming fluids with or without zinc. The number of rats in each group is indicated in the tables.

 
Histological Examination of the Small Intestine
Typical specimens obtained from zinc deficient rats after recovery with either zinc-containing or omitting ORS revealed that with the ORS-zinc, intestinal villi did not show significant expansion, generally associated with a vigorous absorption condition (Fig. 3a). In contrast, tissues from rats which received ORS+zinc exhibited an expansion of the intercellular space, an indication of greater absorption of fluid (Fig. 3b).



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  		Fig. 3. Intestinal villi from rats after two days in recovery from cathartic-induced diarrhea with ORS without zinc (a) or with zinc (b). Note the expansion of the intercellular space in the specimen (b). Magnification: 160x.

 
NF-{kappa}B
As shown in Fig. 4, EMSA analysis of tissues of two zinc deficient rats which had cathartic induced diarrhea and received ORS+zinc during recovery phase exhibited a lesser degree of NF-{kappa}B DNA binding activity than nuclear extracts from small intestine of rats which drank ORS-zinc. This DNA binding activity was specific for NF-{kappa}B consensus binding sequence. Addition of 30-molar excess of non-labeled NF-{kappa}B wild type oligonucleotide resulted in disappearance of NF-{kappa}B specific complex (indicated by arrow), while addition of mutant NF-{kappa}B oligonucleotide did not compete for NF-{kappa}B DNA binding (data not shown). This suggests that zinc addition to ORS may downregulate, to a certain extent, NF-{kappa}B DNA binding activity.



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  		Fig. 4. Electrophoretic mobility assay shift (EMSA) of NF-{kappa}B from specimens obtained from zinc-deficient, cathartic-treated rats which recovered with an ORS with zinc (Zn +) and from rats which received ORS without zinc (Zn -). The areas corresponding a NF-{kappa}B mobility show a significantly greater DNA binding activation in the Zn- rats (densitometry readings: 53.2, 57.2) than in the Zn+ samples (32.1, 48.2). Details of the technique are given in the text.

 

   DISCUSSION
 
This model of combined zinc deficiency and diarrhea, mimicking the condition of infants and children who suffer frequent diarrheal disease episodes, shows that only during active diarrheal conditions does mucosal NOS increase, as would be expected given the association between exaggerated production of NO and intestinal secretion [13]. In rats, treatments with cathartics lead not only to loose stools, but also to an accumulation of fluid in the cecum, which is not observed in normally fed animals [18,19].

In these experiments we showed that ORS with zinc treatment was effective to overcome the effects of a cathartic challenge superimposed to zinc deficiency. However, NO metabolites in cecal contents of zinc deficient, ORS-treated rats with diarrhea remained higher than in zinc deficient rats not exposed to the cathartic.

There were no differences in mucosal NOS between the rats with diarrhea which received ORS+zinc or ORS-zinc, once the cathartics that induce NOS synthesis [14] were discontinued. However, the histologic examination of the rats recovering with ORS+zinc revealed a more responsive jejunal villar structure than that of the ORS-zinc animals. Furthermore, recovery with a zinc containing ORS enabled the rats to revert plasma zinc concentration to values equal to or higher than normal controls, while zinc deficient rats recovering with ORS-zinc remained hypozincemic, still unable to normalize an accepted indicator of zinc status. These results confirm the NO-mediated mechanism involved in experimental diarrheal disease associated with zinc deficiency and substantiates the potential of zinc inclusion in ORS for the treatment of such conditions.

The nuclear transcription factor, NF-{kappa}B, has been shown to play a crucial role in inflammation, cell proliferation and apoptosis [15,24,25] and is a central regulator of the transcriptional activation of a number of genes involved in cell adhesion, immune and proinflammatory responses, differentiation and growth [16,26]. Endotoxemia is associated with increased NF-{kappa}B activity in intestinal mucosa [27]. Similarly, NF-{kappa}B is increased in lamina propria biopsy specimens from patients with inflammatory bowel disease [28]. The proinflammatory effects of NF-{kappa}B have been linked to its promotion of cytokines and acute phase proteins [29].

NF-{kappa}B is reduced in zinc-starved cells, as compared to controls [30]. This finding underlines the importance of zinc in the integrity of the small intestinal mucosa and prevention of oxidative stress [31]. Other experiments have shown that NF-{kappa}B is a modulator of NO production [32]. The present studies are consistent with this association.

In summary, there are grounds to extend this experimental study to the clinical trial level, since the beneficial potential of Zn addition to an ORS may contribute to preserving the integrity and functionality of the small intestine by supplying an essential element directly to its utilization site, possibly reducing the deleterious effects of recurring infections.


   ACKNOWLEDGMENTS
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
 ACKNOWLEDGMENTS
REFERENCES
 
We acknowledge the support of a House Staff grant from North Shore University Hospital (W.A.).

Received July 11, 2001. Accepted October 24, 2001.


   REFERENCES
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
 ACKNOWLEDGMENTS
 REFERENCES
 

  1. Gebhord RI, Karonani R, Priggle WF, McClain CJ: Effect of severe zinc deficiency on activity of intestinal disaccharidases and 3-OH-3-methyl glutaryl coenzyme A reductase in the rat. J Nutr 113: 855–859, 1983.
  2. Golden BE, Golden MHN: Zinc, sodium and potassium losses in the diarrheas of malnutrition and zinc deficiency. In Mills CF, Brenner I, Chesters JF (eds): "Trace Elements in Man and Animals-TEMA 5." Aberdeen, UK: Rowett Research Institute, pp 228–232, 1985.
  3. Bhan MK, Bhandari N: The role of zinc and vitamin A in persistent diarrhea among infants and young children. J Pediar Gastro Nutr 26: 446–453, 1998.
  4. Sazawal S, Black RE, Bhan MK, Bhandari N, Sinha A, Jalla S: Zinc supplementation in young children with acute diarrhea in India. New Engl J Med 333: 839–844, 1995.[Abstract/Free Full Text]
  5. Roy SK, Tomkins AM, Mahalanabis D, Akramuzzaman SM, Haider R, Behrens RH, Fuchs G: Impact of zinc supplementation on persistent diarrhoea in malnourished Bangladeshi children. Acta Paediatr 87: 1235–1239, 1998.[Medline]
  6. Penny ME, Peerson JM, Marin RM, Duran A, Lanara CF, Lönnerdal B, Black RE, Brown RH: Randomized, community-based trial of the effect of zinc supplementation, with and without other micronutrients, on the duration of persistent childhood diarrhea in Lima, Peru. J Pediatr 135: 208–217, 1999.[Medline]
  7. Riordan JF, Vallee BL: Structure and function of zinc metalloenzymes. In Prasad AS, (ed): "Trace Elements in Human Health and Disease." New York: Academic Press, pp 1–20, 1976.
  8. McClain CJ, Adams SL, Shedlovsky S: Clinical spectrum and diagnosis aspects of human zinc deficiency. In Prasad AS (ed): "Essential and Toxic Element in Human Health and Disease." New York: Alan R Liss, pp 69–82, 1988.
  9. Bray TM, Bettger WJ: The physiological role of zinc as an antioxidant. Free Radical Biol Med 8: 281–291, 1990.[Medline]
  10. Cousins JR, Leinart AS: Tissue specific regulation of zinc metabolism and metallothionein genes by interleukin-1. FASEB J 2: 2884–2890, 1988.[Abstract]
  11. Cui L, Takagi Y, Wasa M, Iiboshi Y, Khan J, Nezu R, Okada A: Induction of nitric oxide synthase in rat intestine by interleukin-1{alpha} may explain diarrhea associated with zinc deficiency. J Nutr 127: 1729–1736, 1997.[Abstract/Free Full Text]
  12. McDonald LJ, Murad F: Nitric oxide and cGMP signaling. Adv Pharmacol 34: 263–275, 1995.
  13. Izzo AA, Mascolo N, Capasso F: Nitric oxide as a modulator of intestinal water and electrolyte transport. Dig Dis Sci 43: 1605–1620, 1998.[Medline]
  14. Gaginella TS, Mascolo N, Izzo AA, Autore G, Capasso F: Nitric oxide as a mediator of biscacodyl and phenolphthaleine laxative action: induction of nitric oxide synthase. J Pharmacol Exp Ther 270: 1239–1245, 1994.[Abstract/Free Full Text]
  15. Chen YH, Lu Y, De Plaen IG, Wang LY, Tan XD: Transcription factor NF-{kappa}B signals antianoikic function in trefoil factor 3 on intestinal epithelial cells. Biochem Biophys Res Commun 274: 576–582, 2000.[Medline]
  16. Elewaut D, DiDonato JA, Kim JM, Truong F, Eckemann L, Kagnoff MF: NF-{kappa}B is a central regulator of the intestinal epithelial cell innate immune response induced by infection with enteroinvasive bacteria. J Immunol 163: 1457–1466, 1999.[Abstract/Free Full Text]
  17. Reeves PG, Nielsen FH, Fahey Jr GC: AIN-93 Purified diets for laboratory rodents: final report of American Institute of Nutrition ad-hoc committee on the reformulation of the AIN-76A rodent diet. J Nutr 123: 1939–1951, 1993.
  18. Wapnir RA, Litov RE, Zdanowicz MM, Lifshitz F: Improved water and sodium absorption from oral rehydration solutions based on a rice syrup in a rat model of osmotic diarrhea. J Pediatr 118: S53–S61, 1991.[Medline]
  19. Go JT, Harper RG, Sia CG, Teichberg S, Wapnir RA: Oral rehydration solutions: increased water and sodium absorption by addition of a viscosity-enhancing agent in a rat model of chronic osmotic diarrhea. J Pediatr Gastro Nutr 19: 410–416, 1994.[Medline]
  20. Garvey EP, Furfine ES, Sharazan PA: Purification and inhibitor screening of human nitric oxide synthase isozymes. Meth Enzymol 268: 330–349, 1996.
  21. Marzinzig M, Nussler AK, Stadler J, Marzinzig E, Barthlen W, Nussler NC, Beger HG, Morris Jr SM, Brückner, UB: Improved methods to measure end products of nitric oxide in biological fluids: nitric, nitrate and s-nitrosothiols. Nitric Oxide: Biology and Chemistry 1: 177–189, 1997.
  22. Vancurova I, Miskolci V, Davidson D: NF-{kappa}B activation in tumor necrosis factor {alpha}-stimulated neutrophils is mediated by protein kinase C{delta}. J Biol Chem 276: 19746–19752, 2001.[Abstract/Free Full Text]
  23. Zar JH: "Biostatistical Analysis," 2nd ed. Englewood Cliffs, NJ: Prentice-Hall, pp 185–205, 1984.
  24. Baldwin Jr AS: The NF-{kappa}B and I{kappa}B proteins: new discoveries and insights. Annu Rev Immunol 14: 649–681, 1996.[Medline]
  25. Bauerle PA: I{kappa}B-NF-{kappa}B structures: at the interface of inflammation control. Cell 95: 729–731, 1998.[Medline]
  26. Schottelius AJ, Baldwin AS: A role for the transcription factor NF-{kappa}B in intestinal inflammation. Int J Colorectal Dis 14: 18–28, 1999.[Medline]
  27. Pritts TA, Wang Q, Sun X, Moon MR, Fischer DR, Fischer JE, Wong HR, Hasselgren PO: Induction of the stress response in vivo decreases NF-{kappa}B activity in jejunal mucosa of endotoxemic mice. Arch Surg 135: 860–866, 2000.[Abstract/Free Full Text]
  28. Schreiber S, Nikolaus S, Hampe J: Activation of nuclear factor {kappa}B in inflammatory bowel disease. Gut 42: 477–484, 1998.[Abstract/Free Full Text]
  29. Neurath MF, Becker C, Barbulescu K: Role of NF-{kappa}B in immune and inflammatory responses in the gut. Gut 43: 856–860, 1998.[Abstract/Free Full Text]
  30. Oteiza PI, Clegg MS, Zago MP, Keen CL: Zinc deficiency induces oxidative stress and AP-1 activation in 3T3 cells. Free Radic Biol Med 28: 1091–1099, 2000.[Medline]
  31. Potoka DA, Nadler EP, Zhou X, Zhang XR, Upperman JS, Ford HR: Inhibition of NF-{kappa}B by I{kappa}B prevents cytokine-induced NO production and promotes enterocyte apoptosis in vitro. Shock 14: 366–373, 2000.[Medline]
  32. Lahde Korhonen R, Moilanen E: Regulation of nitric oxide production in cultured human T84 intestinal epithelial cells by nuclear factor-{kappa}B-dependent induction of inducible nitric oxide synthase after exposure to bacterial endotoxin. Aliment Pharmacol Ther 14: 945–954, 2000.[Medline]




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