Lysine fluxes across the jejunal epithelium in lysinuric protein intolerance.

Lysinuric protein intolerance (LPI) is one of a group of genetic diseases in which intestinal absorption of the diamino acids lysine, arginine, and ornithine is impaired. In LPI, the clinical symptoms are more severe than in the kindred disorders. The mechanism of lysine absorption was, therefore, investigated in vitro on peroral jejunal biopsy specimens in seven patients with LPI and 27 controls. The lysine concentration ratio between cell compartment and medium was significantly higher in the LPI group (mean+/-SEM, 7.17+/-0.60) than in the controls (5.44+/-0.51). This was also true for the intracellular Na concentration (LPI, 73.6+/-10.8 mM; controls 42.3+/-3.7 mM). The rate of unidirectional influx of lysine across the luminal membrane was Na dependent and was the same in the two groups. In the absence of an electrochemical gradient, net transepithelial lysine secretion was observed in LPI. This was entirely the result of a 60% reduction of the unidirectional flux from mucosa to serosa. Calculation of unidirectional fluxes revealed the most striking difference at the basolateral membrane, where the flux from cells to serosa was reduced by 62% and the corresponding permeability coefficient reduced by 71%. A progressive reduction in short-circuit current appeared in the epithelia of all four patients with LPI tested after addition of 3 mM lysine. Thus, LPI appears to be the first disease in which a genetically determined transport defect has been demonstrated at the basolateral membrane.

Effects of cholera toxin on cellular and paracellular sodium fluxes in rabbit ileum.

The diarrhea observed in patients with cholera is known to be related to secretion of water and electrolytes into the intestinal lumen. However, the exact mechanisms involved in these secretory processes have remained unclear. Although it is clear that purified toxin acts on epithelial cell metabolism, its activity on Na+ transport across intestinal mucosa is equivocal: reported either to prevent net Na+ absorption or to cause net secretion of Na+ from serosa to mucosa. Since total transmural Na+ fluxes across "leaky" epithelia involve very significant movement via a paracellular shunt pathway, we studied the effects of cholera toxin on the cellular and paracellular pathways of Na+ movement. Unidirectional Na+ fluxes were examined as functions of applied potential in control tissues and in tissues from the same animal treated with purified cholera toxin. Treatment of rabbit ileum in vitro with toxin simulated the cellular component of serosa-to-mucosa Na+ flux (from 2.41 +/- 0.49 muequiv./h per cm2 under control conditions to 4.71 +/- 0.43 muequiv./h per cm2 after treatment with toxin, P less than 0.01). The effect of cholera toxin on Na+ movement through the cells from mucosa to serosa appeared to be insignificant. Finally, a marked decrease in the Na+ permeability (P less than 0.01) and no detectable significant changes in transference number for Na+ of the paracellular shunt pathway were observed following treatment with cholera toxin. These results provide direct evidence for the hypothesis that purified cholera toxin stimulates active sodium secretion but has minimal effect on sodium absorption.

A U-shaped bioartificial pancreas with rapid glucose-insulin kinetics. In vitro evaluation and kinetic modelling.

The lag in insulin release in response to glucose is an obstacle to the development of hybrid pancreatic devices, in which an artificial membrane protects transplanted islets against immune rejection. We designed a U-shaped bioartificial pancreas, in which the blood channel surrounds the islet chamber consisting of two flat membranes; blood circulates successively above the first membrane and then in the reverse direction, below the second membrane. Isolated rat islets were introduced into the chamber, which was perfused with Krebs buffer, and the kinetics of insulin release in response to glucose was determined. During a 20-min, 2.8-20-mM, square-wave glucose stimulation, insulin release in the effluent of the device rose from 0.7 +/- 0.2 to 3.2 +/- 1.0 ng/100 islets/min (P less than 0.05) within 3 min, and reached a maximal level of 12.8 +/- 3.3 ng/100 islets/min at 10 min; 5 min after the return of the glucose concentration to substimulatory level, insulin release dropped from 11.3 +/- 1.5 to 8.0 +/- 1.7 ng/100 islets/min (P less than 0.05), and reached basal value (1.0 +/- 0.2 ng/100 islets/min) 40 min after the end of the stimulation. A 0.1-mM/L/min ramp increase in glucose concentration triggered a significant rise in insulin release (P less than 0.02) when the glucose concentration reached 5.3 +/- 0.2 mM; islets concomitantly perifused within a chamber set up without membrane responded to the same glucose stimulation 5 min earlier. For up to 1000 islets, insulin release in response to glucose was linearly correlated to the number of islets (N = 12, P less than 0.01), indicating that insulin did not significantly inhibit its own secretion in this system. Finally, during glucose stimulation, the insulin concentration in the effluent from the chamber was found to be four times the concentration present at the turning point of the blood channel, suggesting that insulin was transferred into the perfusing medium in part by a countercurrent flux of ultrafiltrate crossing the membranes. We present herein the kinetic modelling of glucose and insulin transfer in this "ultrafiltration chamber," whose functional characteristics are compatible with closed-loop insulin delivery.

Whole body de novo amino acid synthesis in type I (insulin-dependent) diabetes studied with stable isotope-labeled leucine, alanine, and glycine.

Dynamic aspects of whole body alanine and glycine metabolism have been explored in insulin-dependent (type I) diabetic subjects. Using a primed, continuous intravenous (i.v.) infusion of [2H3]alanine and [15N]glycine given simultaneously with [1-13C]leucine, whole body alanine and glycine fluxes and their rates of de novo synthesis were measured in 6 diabetic young men. Subjects were studied in the postabsorptive state, after blood glucose was clamped overnight at 15.2 +/- 0.3 mM, and then, on the following night, at 5.9 +/- 0.2 mM (insulin infusion rates of 0.24 +/- 0.09 and 1.65 +/- 0.20 U/h, respectively). In the normoglycemic state, leucine, alanine, and glycine fluxes averaged 88 +/- 4, 378 +/- 39, and 155 +/- 8 mumol X kg-1 X h-1, respectively. Based on the leucine flux, alanine and glycine de novo synthesis rates were 264 +/- 36 and 67 +/- 8 mumol X kg-1 X h-1. In the hyperglycemic state, leucine flux increased 23% (P less than 0.01), alanine flux rose slightly (+5%) but significantly (P less than 0.05), while alanine de novo synthesis and glycine flux remained unchanged and glycine de novo synthesis decreased by 33% (P less than 0.001). These results show that small alterations in peripheral alanine inflow in the hyperglycemic state reflect increased proteolysis and suggest that increased circulating plasma glucose does not contribute to de novo alanine synthesis in the absence of adequate insulin effect and/or augmented glucose tissue uptake. These observations also reveal the importance of insulin in the maintenance of whole body leucine economy, since a lower rate of insulin administration was associated with an increased rate of leucine oxidation.

Characteristics of sodium flux from serosa to mucosa in rabbit ileum.

Sodium flux from serosa to mucosa, J(sm) (Na) in rabbit ileum in vitro has been studied as a function of applied electrical potential at equal sodium concentrations in the bathing solutions. The results indicate that J(sm) (Na) involves two pathways, a diffusional flux through a paracellular shunt pathway and a flux that is independent of applied potential and presumably involves a transcellular pathway. The latter pathway comprises approximately 25 % of J(sm) (Na) in Ringer's solution containing 10 mM glucose and 25 mM bicarbonate. It is stimulated significantly by theophylline unaffected by removal of glucose or addition of ouabain but is reduced to negligible values by anoxia, dinitrophenol, and replacement of all chloride and bicarbonate by isethionate. Thus this component of J(sm) (Na) has a number of characteristics consistent with involvement in a specific secretory process mediating an electrically neutral secretory transport of sodium plus anion from serosa to mucosa. In addition to stimulating this process, theophylline significantly reduced the permeability of the paracellular shunt pathway to sodium.

Viable starter culture, beta-galactosidase activity, and lactose in duodenum after yogurt ingestion in lactase-deficient humans.

Ten lactose malabsorbers were intubated and given fresh or heated yogurt to which polyethylene-glycol (PEG) and spores of Bacillus stearothermophilus (SBS) had been added as internal standards. In duodenal samples taken after fresh yogurt ingestion, viable starter culture was detected for 60 min in 6 of 7 subjects and the ratio of microbial beta-galactosidase activity to SBS remained similar during this period to its value in the preingested yogurt. In the two groups ingesting fresh and heated yogurt respectively, ratios of lactose to PEG remained similar to preingested values for 90 min and duodenal pH remained less than 5.1. In vitro, at pH 5.0, beta-galactosidase activity in yogurt dropped by 80%. These data clearly show that after fresh yogurt ingestion, viable starter culture reaches the duodenum and contains beta-galactosidase activity. However, the buffering capacity of the yogurt that protects bacteria from acidic gastric secretion also prevents microbial beta-galactosidase from hydrolyzing lactose in the duodenum.

Effect of chronic ingestion of a fermented dairy product containing Lactobacillus acidophilus and Bifidobacterium bifidum on metabolic activities of the colonic flora in humans.

Nine healthy volunteers were studied before, during, and after ingesting a fermented dairy product containing Lactobacillus acidophilus, Bifidobacterium bifidum, and mesophilic cultures (Streptococcus lactis and S cremoris) for 3 wk. Hydrogen and methane productions and fecal beta-galactosidase and beta-glucosidase activities were measured as indicators of fermentation capacity of the colonic flora. Fecal concentrations of nitroreductase, azoreductase, and beta-glucuronidase, which may be implicated in colonic carcinogenesis, were also assessed. Hydrogen and methane productions, fecal beta-galactosidase, beta-glucuronidase, and azoreductase activities did not change over three 3-wk periods whereas fecal beta-glucosidase activity increased (42 +/- 6, 91 +/- 12, and 40 +/- 6 IU/g N, P less than 0.01) and nitroreductase decreased (0.87 +/- 0.13, 0.54 +/- 0.11, and 0.57 +/- 0.08 IU/g N, P less than 0.05).

Goat's milk as a substitute for cow's milk in undernourished children: a randomized double-blind clinical trial.

OBJECTIVE: This paper compares the effects of goat's milk and cow's milk on weight gain and fat absorption, in children with overt malnutrition. METHODS: Thirty hospitalized malnourished children aged from 1 to 5 years were included in a randomized double-blind trial. The children were fed either goat or cow's milk with a randomized will defined composition, added with vegetable oil, sugar, vitamins and minerals o achieve 1,000 kcal/liter. Children were offered 100 kcal/kg on the first day, with a regular daily increase in energy intake thereafter that reached 200 kcal/kg per day on the tenth day. RESULTS: Both groups of children had the same degree of malnutrition on inclusion. The mean weight-for-height Z score was -1.7 in both groups. One death with candidiasis occurred in the goat's milk group. Weight gain was similar in both groups: 8.5 g/kg/day (SE = 1.37) with goat's milk and 7.8 (SE = 1.9) with cow's milk. There was no significant difference in HEM intake: 157 ml/kg/day (SE = 4), vs 162 (SE = 4) for goat and cow's milk, respectively. Fat absorption coefficients on the 15th day of treatment were also similar in both groups. CONCLUSION: These results suggest that goat's milk has a nutritional value similar to that of cow's milk and could be used as an alternative to cow's milk for rehabilitating undernourished children.

Production of arachidonic acid metabolites by the colon adenocarcinoma cell line HT29 cl.19A and their effect on chloride secretion.

Eicosanoids were found in large amounts in the colonic mucosa of patients suffering from inflammatory bowel diseases and colonic adenocarcinoma. The aim of this study was to evaluate the role of the intestinal epithelial cells in the arachidonic acid metabolism and their functional response to certain eicosanoids. We used the human adenocarcinoma epithelial cell line HT29 cl.19A cell, which is an in vitro model of colon carcinoma and ion transport. These cells were found to express 5- and 15-lipoxygenase, leukotriene A4 hydrolase and cyclooxygenase-1 and -2 mRNAs. We observed an arachidonic acid metabolism via 5-lipoxygenase pathway despite the lack of FLAP mRNA expression and that certain eicosanoids such as hydroperoxy- and hydroxyeicosatetraenoic acids stimulate chloride secretion.

Cytokine-induced alteration of the epithelial barrier to food antigens in disease.

The alteration of the intestinal epithelial barrier is often a consequence of various intestinal diseases but may also be the starting point of these diseases. Undigested food antigens are transported across the intestinal epithelium by a transcytotic mechanism, including a processing within the enterocytes, and leading to the passage of intact proteins, peptides, and amino acids to the underlying mucosa. Inflammation and infection lead to the upregulation of the transport and processing of food proteins; for example, IFN gamma increases the rate of transcytosis and alters, like TNF alpha, the tight junction permeability. Infection of gastric digestive epithelia with Helicobacter pylori also increases the antigenic load transmitted to the underlying immune system by inhibiting the enterocytic lysosomal degradation of proteins. In allergic diseases, such as cow's milk allergy, TNF alpha may be involved in the intestinal dysfunction and the associated enteropathy.

Glutamine metabolism after small intestinal resection in humans.

Glutamine and leucine kinetics were measured using stable isotopes in five enterectomized patients (residual small bowel, 80 +/- 25 cm [mean +/- SE]) who were in a near normal nutritional status at distance from surgery. While parameters of leucine metabolism were normal, rates of whole body glutamine utilization were reduced by 20% in the patients. The data suggest that the small intestine plays a prominent role in glutamine utilization in vivo in humans.

Whole-body protein metabolism assessed by leucine and glutamine kinetics in adult patients with active celiac disease.

To assess the effect of increased renewal of intestinal epithelial cells on leucine and glutamine (Gln) turnover, 4-hour intravenous infusions of L-[1-(13)C]leucine and L-[2-(15)N]Gln were administered to five adult patients with active celiac disease in the postabsorptive state. There was a 35% increase in leucine flux (micromoles per kilogram per hour) in patients (117 +/- 17) compared with healthy controls (96 +/- 11, P < .03). Gln flux was increased by 13% in patients (377 +/- 35) versus controls (335 +/- 16, P < .04). These results suggest that active celiac disease, characterized by villous atrophy and crypt cell hyperplasia, is associated with a dramatic increase in whole-body protein breakdown as assessed by 13C-leucine, which may contribute per se to the protein malnutrition status of the patients. The increase in Gln utilization as assessed by L-[2-(15)N]Gln was moderate, but may have been offset due to the villose atrophy and ensuing reduced intestinal epithelial cell mass. The results are consistent with the concept that increased renewal of intestinal epithelial cells represents a sizable fraction of whole-body protein turnover and that Gln is an important fuel for epithelial intestinal cells in vivo.

Energy and protein metabolism in malnutrition due to nonneoplastic gastrointestinal diseases.

Although a reduction in both energy expenditure and protein turnover has been demonstrated in starved volunteers, few metabolic data are available for patients in whom malnutrition is due to nonneoplastic gastrointestinal diseases. Chronically malnourished, unstressed adult patients with nonneoplastic gastrointestinal diseases (body mass index, 15.8 +/- 2.5 kg/m2, n = 13) and healthy control subjects (n = 10) were studied in the postabsorptive state using indirect calorimetry, as well as substrate fluxes of L[1-13C]leucine, L-[2-15N]glutamine (seven patients and six controls), and D[6,6-2H2]glucose (seven patients and eight controls). Resting energy expenditure (REE) expressed in kilocalories per 24 hours was significantly lower in patients than in controls; REE expressed per unit of fat-free mass (FFM) was not significantly different in both groups. Whole-body leucine turnover, oxidation, and nonoxidative disposal rates, based on either 13C-leucine or 13C-alpha-ketoisocaproic acid (KIC) enrichments, and glucose turnover rate were not significantly different between malnourished patients and controls. Moreover, glutamine turnover was increased by 28% in malnourished patients as compared with normal volunteers (429.8 +/- 86.8 v 334.9 +/- 15.9 mumol/kg/h, P = .02). These results suggest that hypometabolic adaptation, although previously documented in starved volunteers, is not operative during states of chronic malnutrition due to gastrointestinal disease. The increase in glutamine turnover rate might represent an adaptative mechanism to malnutrition for preservation of visceral mass or function.

Use of 13C-labeled glucose for estimating glucose oxidation: some design considerations.

Use of 13C-labeled glucose for estimating in vivo rates of glucose oxidation faces several difficulties, particularly the accurate determination of the output of 13C in expired air. In an investigation of wholebody glucose metabolism in healthy adult humans, using a continuous intravenous infusion of D-[U-13C]glucose, we found that a precise estimate of the rate of glucose oxidation was difficult to achieve when the study included infusions with unlabeled glucose. Problems arose 1) as a result of the slow rate at which the 13CO2 released by glucose oxidation reaches an equilibrium in expired air CO2 and 2) due to the contribution to 13CO2 output by the natural 13C in the unlabeled glucose that was infused. In a subsequent series of experiments in healthy young adults, we found that the entry of 13CO2 released by the tissues into the bicarbonate pool and into the expired air is relatively slow and a tracer infusion protocol of approximately 6 h is required for determination of glucose oxidation. This applies when metabolic states are changed acutely during the experiment or when unlabeled glucose is infused. However, for resting subjects in the basal postabsorptive state we confirmed that the time required to achieve a steady state in the 13C enrichment of expired air can be shortened significantly by the use of a NaH13CO3 priming dose, even when this dose varies from the ideal.

Comparison of the antisecretory effect of endogenous forms of peptide YY on fed and fasted rat jejunum.

It is intriguing that the antisecretory peptide YY is present in plasma in two forms: PYY1-36 and PYY3-36. PYY3-36 has been found in human and rabbit blood within 30 min of the beginning of the meal, when the peak of water and electrolyte secretion occurs in the duodeno-jejunum. The aim of this study was therefore to compare the antisecretory effect of PYY1-36 and PYY3-36 in fed and fasted rat jejunum. The variations in electrolyte secretion were assessed by measuring the variations in short-circuit current (delta Isc) and transepithelial isotopic chloride fluxes in jejunal mucosa isolated from fed and fasted animal, and mounted in Ussing Chambers. In fasted animals, 2 x 10(-7) M PYY3-36 induced a reduction in Isc of -0.50 +/- 0.01 microEq/hr.cm2, which was not statistically different from that induced by 2 x 10(-7) M PYY1-36 (-0.60 +/- 0.01 microEq/h cm2). In contrast, in fed animals, 2 x 10(-7) M PYY3-36 did not trigger a significant response on Isc and net chloride flux, while the response to PYY1-36 was present but blunted. The absence of response was probably not related to the presence of secretory peptides because PYY3-36 was still able to induce a reduction in Isc after stimulation by a series of 10 different secretory peptides. After 10(-8) M PYY3-36 addition to an epithelium from the fasted animal, response to 10(-7) M PYY3-36 was blunted for 30 min and returned to control value after 60 min. Plasma concentration of PYY was higher in the fed rats compared to fasted (213.78 +/- 38 vs. 53.62 +/- 11.47 pg/ml p < 0.01). After incubation of crypt cells with or without 0.1 microM of unlabeled PYY for 60 min, Scatchard analysis of equilibrium binding data show that binding capacity (Bmax) of receptors was reduced when crypt cells were previously incubated with unlabeled PYY without significant modification of dissociation constants. Bmax were 183 +/- 27 in control vs. 56 +/- 11 fmol/mg protein. These results confirm the antisecretory activity of PYY1-36 in the jejunum of fasted and fed rats. They further indicate that PYY3-36 displays similar activity to PYY1-36 in fasted animals, but lack of activity in fed animals. These results suggest that the two circulating forms of PYY act as antisecretory peptides by two different mechanisms, implying a C-terminal specificity.

Effects of peptide YY and its analogues on chloride ion secretion in fed and fasted rat jejunum.

The aim of our study was to determine whether a meal modifies the antisecretory response induced by PYY and the structural requirements to elicit antisecretory effects of analogue PYY(22-36) for potential antidiarrhea therapy. The variations in short-circuit current (Isc) due to the modification of ionic transport across the rat intestine were assessed in vitro, using Ussing chambers. In fasted rats, PYY induced a dose- and time-dependent reduction in Isc, with a sensitivity threshold at 5 x 10(-11) M (delta Isc -2 +/- 0.5 microA/cm2). The reduction was maximal at 10(-7) M (Isc -23 +/- 2 microA/cm2), and the concentration producing half-maximal inhibition was 10(-9) M. At 10(-7) M, reduction of 1sc by PYY reached 90% of response to 5 x 10(-5) M bumetanide. The PYY effect was partly reversed by 10(-5) M forskolin (Isc + 13.43 +/- 2.91 microA/h.cm2, p < 0.05) or 10(-5) M dibutyryl adenosine 3',5' cyclic monophosphate (Isc + 12 +/- 1.69 microA/cm2, p < 0.05). Naloxone and tetrodotoxin did not alter the effect of PYY. In addition, PYY and its analogue P915 reduced net chloride ion secretion to 2.85 and 2.29 microEq/cm2 (p < 0.05), respectively. The antisecretory effect of PYY was accompanied by dose- and time-dependent desensitization when jejunum was prestimulated by a lower dose of peptide. The antisecretory potencies exhibited by PYY analogues required both a C-terminal fragment (22-36) and an aromatic amino acid residue (Trp or Phe) at position 27. At 10(-7) M the biological activity of PYY was lower in fed than fasted rats (p < 0.001). Our results confirm the antisecretory effect of PYY, but show that the fed period is accompanied by desensitization, similar to the transient desensitization observed in the fasted period with cumulative doses. This suggests that PYY may act as a physiological mediator that reduces intestinal secretion.

Absorption of intact morphiceptin by diisopropylfluorophosphate-treated rabbit ileum.

The amidated beta-casomorphin morphiceptin Tyr-Pro-Phe-Pro-NH2 is an opioid peptide isolated from bovine milk beta-casein digests whose physiological significance remains unclear. Opiates are known to modify intestinal electrolyte transport by acting on receptors located on the serosal side of the intestine. The aim of the present study was to determine under what conditions morphiceptin can act from the luminal side. When added to the serosal side of untreated rabbit ileum in an Ussing chamber in vitro, 10(-3) M morphiceptin acted through an opiate mechanism to reduce simultaneously short-circuit current (delta Isc = 0.33 +/- 0.07 muEq.hr-1.cm-2) and stimulate net Na and Cl absorption (delta JnetNa = 1.62 +/- 0.11 and delta JnetCl = 2.07 +/- 0.08 muEg.hr-1.cm-2). After mucosal addition under the same conditions, morphiceptin was degraded without any opiate action on electrolyte transport. Pretreatment of the ileum by 10(-3) M diisopropylfluorophosphate, which inhibited brush-border dipeptidylpeptidase IV, prevented mucosal degradation of morphiceptin. Under these conditions, morphiceptin was able, when added mucosally, to cross the epithelium intact (Jm----s = 1.8 +/- 0.16 nmole.hr-1.cm-2) and to stimulate electrolyte absorption by means of an opioid mechanism (delta Isc = 0.22 +/- 0.02 muEq.hr-1.cm-2). These results showed that the action of morphiceptin from the lumen depends on its transfer intact to the serosal side of the intestine where the opiate receptors are located. The limiting step in this transfer is at the brush-border membrane, where dipeptidylpeptidase IV in particular seems to play a major role.

Antral gastric permeability to antigens in mice is altered by infection with Helicobacter felis.

OBJECTIVE: Gastric inflammation is observed not only during Helicobacter pylori infection but also after eradication of the bacterium. The hypothesis that an altered gastric permeability could be involved was tested using a model of mice infected with Helicobacter felis. DESIGN: The antral and corpus gastric permeability during infection and after eradication of bacteria was studied. METHODS: Gastric fragments from the antrum and corpus of healthy mice, mice infected with H. felis, or mice after bacterial eradication, were mounted in Ussing chambers, and fluxes of sodium (JNa), mannitol (JMan) and horseradish peroxidase (HRP) under intact (JHRPi) and degraded (JD) form were measured. RESULTS: In healthy mice, JNa, JMan, JHRPi and JD, respectively, were greater in the antrum (6.5 +/- 0.5 microEq/h.cm2; 0.137 +/- 0.016 micromol/h.cm2; 30.4 +/- 7.4 ng/h.cm2 and 852 +/- 173 ng/h.cm2) than in the corpus (5.0 +/- 0.3 microEq/h.cm2; 0.085 micro 0.013 micromol/h.cm2; 9.5 +/- 2.8 ng/h.cm2 and 434 +/- 139 ng/h.cm2). In H. felis-infected mice, HRP fluxes in the antrum were increased (JHRPi = 182 +/- 86, JD = 948 +/- 94 ng/h.cm2) as compared to controls (JHRPi = 10.3 +/- 2.6, JD = 458 +/- 98 ng/h.cm2). Bacterial eradication led to the reduction of intact (JHRPi = 53 +/- 26 ng/h.cm) but not of degraded (JD = 844 +/- 213 ng/h.cm) HRP fluxes. After eradication, degraded HRP fluxes returned to normal in mice without inflammation (JD = 558 +/- 36 ng/h.cm2) but not in those with persistent inflammation (JD = 987 +/- 310 ng/h.cm2). CONCLUSIONS: The results suggest that during H. felis infection, bacterial colonization and inflammation lead to an increased gastric permeability along the direct and degradative pathways, respectively. Such an increased antigenic load could contribute to the perpetuation of gastric inflammation after bacterial eradication, and possibly to food protein sensitization.

The effect of L-glutamine on salt and water absorption: a jejunal perfusion study in cholera in humans.

OBJECTIVES: To assess the efficacy of an L-glutamine solution on jejunal salt and water absorption in cholera patients. DESIGN: A randomized double-blind jejunal perfusion study. SETTING: International Centre for Diarrhoeal Disease Research, Bangladesh. PATIENTS: Nineteen adults with acute cholera. INTERVENTIONS: Perfusion of balanced salt solutions alternated with defined glucose salt solution and glutamine glucose salt or alanine glucose salt solutions. MAIN OUTCOME MEASURES: Net jejunal water and sodium secretion. RESULTS: Perfusion of glutamine in the presence of glucose significantly reduced net water secretion (JnetH2O = -2.6 +/- 1.3 ml/h/cm) and also reduced net sodium secretion (JnetNa = -213 +/- 153 mumol/h/cm). Similar results were observed during the perfusion of solutions that contained alanine in addition to glucose (JnetH2O = -4.2 +/- 1.1 ml/h/cm and JnetNa = -444 U +/- 142 mumol/h/cm, respectively) or glucose alone (JnetH2O = -4.3 +/- 1.7 ml/h/cm and JnetNa = -452 +/- 212 mumol/h/cm, respectively). In addition, a higher basal secretion was associated with a greater stimulation of water absorption (F = 17, P < 0.001). CONCLUSION: Glutamine in the presence of glucose significantly reduces net water secretion and also reduces sodium secretion; higher basal secretion is associated with greater water absorption. As glutamine is able to stimulate water absorption to the same degree as glucose and alanine, and because it has the theoretical advantage of providing fuel for the mucosa, the inclusion of glutamine as the sole substrate in oral rehydration solution warrants further study.

Risk factors for fatal diarrhoea among dehydrated malnourished children in a Madagascar hospital.

OBJECTIVE: To examine mortality risk factors during rehydration among 6-35 month malnourished children with diarrhoea. DESIGN: Data collected prospectively during a clinical trial comparing two oral rehydration solutions (ORS). SETTING: Paediatric ward. SUBJECTS: Study children had either a weight-for-age Z-score below -2 or a weight-for-height below 70% of NCHS median. All had diarrhoea for < 5 days. 150 were enrolled and two were excluded for intercurrent infection. INTERVENTION: Children were randomly allocated to receiving 100 ml/kg of standard or rice-based ORS during the 6h following admission. Then they received 420 kJ/kg/day of high energy milk, progressively increased to 840 kJ/kg/day. RESULTS: Mortality rate was 16% and with no difference by ORS group. In univariate analysis, the risk of dying (mean odds ratio; 95% confidence interval) was significantly higher among girls (3.5; 1.4-8.9), in non-breast-fed children (3.7; 1.4-9.6) and in children with a low weight-for-height (5.1; 1.9-14.1). Low weight, moderate or severe dehydration, low plasma specific gravity or total plasma protein and longer duration of diarrhoea before inclusion also were significant risk factors. In multivariate logistic analysis, only absence of breast-feeding was associated with a higher risk of dying among girls with a low weight-for-height. Among them, eight out of nine died, compared to 15 out of 139 for other children. CONCLUSION: Breast-feedings protected severely malnourished girls against death from diarrhoea even when dehydration was corrected. Mechanisms underlying this selective effect are poorly understood.