In vitro uptake of amino acids in the jejunal mucosa of patients with cholera.

In vitro uptake of 14C-labelled amino acids was studied in jejunal mucosa biopsy specimens from 64 adults admitted for treatment of cholera (proven by stool culture) within 48 hours of onset of watery diarrhoea to determine the state of amino acid carriers in the jejunal mucosa during actively purging disease. Continued absorption of amino acids by the NBB carrier (for neutral amino acids), the Y+ system (for dibasic amino acids), and the PHE carrier were operative even during the actively purging stage of watery diarrhoea due to cholera. The IMINO carrier for absorption of N-substituted amino acids was found to be inoperative during cholera but the imino acids could be absorbed by the PHE carrier. This study demonstrates continued intestinal absorption of amino acids during cholera, provides scientific basis for use of amino acids in "improved" oral rehydration solutions utilising amino acid transport systems which are linked to the absorption of sodium (and water) so that reduction in diarrhoeal stools can be achieved, and emphasises the importance of maintaining feeding during acute diarrhoea to prevent the development of malnutrition.

The effect of Escherichia coli heat-stable (STA) enterotoxin on in vitro uptake of amino acids by small intestine of sucking rats during fluid accumulation.

In vitro uptake of 14C-labelled amino acids by segments of small intestine was determined in sucking (2-4-d-old) Wistar rats. Intragastric injections of heat-stable (ST) toxin of enterotoxigenic Escherichia coli (ETEC) were given to produce fluid accumulation, defined as a gut weight: carcass weight value of > 0.085. Continued active uptake of the prototypic amino acids, leucine (by active transport system 1 for monoamino monocarboxylic (neutral) amino acids), lysine (by active transport system 2 for dibasic amino acids), and proline (by active transport system 3 for N-substituted amino acids), persisted during the active fluid accumulation response to ETEC ST toxin. The mean Kt and mean Vmax of the amino acid transport systems were similar in control (non-injected) and ST toxin-injected rats. The present study provides a scientific basis for the use of amino acids in oral rehydration solutions utilizing amino acid transport systems which are linked to absorption of Na (and water) so that reduction in diarrhoeal stools can be achieved, and emphasizes the importance of maintaining feeding during acute diarrhoea to prevent development of malnutrition.

Effect of berberine on enterotoxin-induced intestinal fluid accumulation in rats.

We have determined the effects of berberine (Berberis aristita) on intestinal fluid accumulation due to enterotoxigenic E. coli (ETEC) heat-stable (ST) toxin in suckling (24-days old) Wistar rats. Intestinal fluid accumulation occurred in suckling Wistar rats by administration of culture filtrate containing ST-producing ETEC in serial dilutions up to 1/8 dilution by oral or intragastric route. When berberine (0.1 mg) and 1/8 dilution of ST-toxin were given together by oral or intragastric injection, a significant (p < 0.01) reduction in fluid accumulation was observed. Neither treatment with berberine orally before intragastric injection of ST-toxin nor intragastric administration of berberine after ST-toxin reduced the fluid accumulation due to ST-toxin.

Decreased phosphodiesterase activity in cholera toxin-induced hypersecretion in suckling rats.

During cholera toxin (CT)-induced hypersecretion in suckling rats, the rise in the intestinal cAMP concentration was found to be accompanied by a decrease in the cAMP-phosphodiesterase activity. The results suggest the involvement of phosphodiesterase (PDE) as one of the factors governing the rise of cAMP.

Sodium balance during acute diarrhoea in malnourished children.

Forty-six male children 12-59 months old (27 malnourished and 19 with normal nutrition) admitted for acute water diarrhoea of less than 48 hours' duration were studied. Using a metabolic balance and separate collections of urine and stools over each 6-hour period, balance studies were carried out up to 48 hours. Blood, stool, and urine samples were analysed for sodium and potassium levels. Serum cortisol levels were determined using radio-immunoassay in a subsample of six normal and five malnourished children. Malnourished children lost more sodium in their stools and urine during diarrhoea, so that they had significantly diminished gut net sodium balance and significantly diminished total body sodium balance. Significantly higher levels of serum cortisol were observed initially on admission among children with malnutrition. This study demonstrated that malnourished children had poorer sodium balance during acute diarrhoea.

House-dust mite allergy and eosinophilia in patients with asthma in Rangoon (Yangon).

Skin tests were done by prick and intradermal techniques, using house dust mite (Dermatophagoides pteronyssinus) antigen on 35 patients with early onset asthma, 33 with late onset asthma, 43 with asthma and frequent cough with sputum production (chronic bronchitis) and 30 control subjects. Absolute blood eosinophil and sputum eosinophil (as percentage of leukocytes) counts were performed on each patient. Positive skin tests to house dust mite antigens were significantly more frequent in each of the patient groups (35-75%) than in control subjects (0%), but were not significantly different among the three groups of asthmatics. All three groups of asthmatics had significantly higher mean blood absolute eosinophil counts and sputum eosinophil counts than control subjects, eosinophilia being most frequent in patients with early onset asthma. These findings suggest the importance of exposure to house dust mite antigens in the development of asthma in patients in Rangoon (Yangon), Burma (Myanmar).

Comparison of glucose/electrolyte and maltodextrin/glycine/glycyl-glycine/electrolyte oral rehydration solutions in cholera and watery diarrhoea in adults.

One hundred and eight male adults (mean age 33 +/- 1.7 years) presenting with watery diarrhoea of less than 48 hours duration at home prior to hospitalization and with clinically evident (grade II, severe) dehydration were admitted into a randomized double-blind clinical trial; 54 were treated with standard oral rehydration solution (ORS)--WHO formulation containing citrate--and 54 with an improved ORS formulation which contained, in addition to the standard formula, maltodextrin 20 g (instead of glucose), glycine 4 g and glycyl-glycine 4 g. Patients with clinical cholera were given tetracycline 500 mg q.i.d. Vibrio cholerae was detected in 85 patients. The clinical characteristics of patients in the two groups were comparable. The improved ORS did not reduce the volume of diarrhoeic stools in cholera; indeed, patients with cholera who were treated with improved ORS had larger diarrhoea stool volumes. However, those cholera patients given improved ORS showed significantly greater weight gains during the first six-hour period, at the end of the second day, and at discharge. On the other hand, non-cholera patients treated with improved ORS had significantly smaller diarrhoeic stool volumes during the six to 24-hour significantly smaller diarrhoeic stool volumes during the six to 24-hour period (i.e. during the commencement of maintenance rehydration therapy).

Comparison of glucose/electrolyte and maltodextrin/glycine/glycyl-glycine/electrolyte oral rehydration solutions in acute diarrhea in children.

Male children (N = 101) 6-35 months of age presenting with acute watery diarrhea for less than 48 h at home before hospitalization were admitted into a randomized, double-blind clinical trial. Fifty-one children were treated with standard oral rehydration solution (ORS) (World Health Organization [WHO] formulation containing citrate) and 50 were treated with an improved ORS formulation (containing, in addition to the standard formula, 20 g maltodextrin instead of glucose, and 4 g glycine and 4 g glycyl-glycine). None were given antibiotics. No i.v. infusions were given. Rotavirus was detected by enzyme-linked immunosorbent assay in stools of 43 children. Clinical characteristics of children in the two treatment groups were comparable. Improved ORS did not produce significant reduction in the volume of diarrhea stools. Children given improved ORS had greater weight gain than that observed in children treated with standard ORS, but the differences were not statistically significant except at the end of the first 24 h. Among children with rotavirus diarrhea, no significant differences were observed between the 23 children who received improved ORS and the 20 who received standard ORS.

Effect of cholera toxin on L-[14C]glycine uptake and intestinal cell enzymes in rabbit.

The uptake of L-[14C]glycine and the activities of intracellular marker enzymes of enterocytes were studied in ligated small intestinal segments of rabbits during experimental cholera induced by intra-intestinal injection of pure cholera toxin (CT). No significant difference was observed in the active uptake of L-[14C]glycine between the CT-injected small intestinal segments and the saline-injected control segments, indicating that there is an intact active transport system for intestinal absorption of L-[14C]glycine during experimental cholera in rabbits. Apart from a significant increase in the activity of a brush border marker enzyme (alkaline phosphatase), there was no significant difference between the activities of marker enzymes for lysosomes (acid phosphate), microsomes (glucose-6-phosphatase), mitochondria (succinate dehydrogenase), and a cytosol enzyme (proteinase) in mucosal homogenates of CT-injected small intestinal segments compared to controls. The finding of an intact mitochondrial marker enzyme together with intact L-[14C]glycine absorption provides a scientific basis for considering the use of glycine and other monoamino monocarboxylic amino acids in "improved" oral rehydration solutions for the treatment of acute diarrhea, including cholera.

Etiology of acute diarrhoea among children in developing countries: a multicentre study in five countries.

A 2-year etiological survey of acute diarrhoea in children aged 0-35 months who were attending treatment facilities was carried out using a standardized protocol in five hospitals in China, India, Mexico, Myanmar, and Pakistan. A total of 3640 cases of diarrhoea and 3279 age- and sex-matched controls were studied; about 60% of the patients were aged less than 1 year and 60% were male. An enteric pathogen was detected in 68% of the cases and in 30% of the controls. In all the study centres, the pathogens most strongly associated with disease were rotavirus (16% of cases, 2% of controls), Shigella spp. (11% of cases, 1% of controls) and enterotoxigenic Escherichia coli (16% of cases, 5% of controls). Rotavirus was commonest among 6-11-month-olds, accounting for 20% of all cases in this age group; 71% of all rotavirus episodes occurred during the first year of life. Shigella spp. were commonest among those aged 12-23 months and 24-35 months, accounting for 22% and 27% of the cases, respectively. The proportion of cases that yielded no pathogen was inversely related to age, being highest (41%) among infants below 6 months of age and lowest (19%) among those aged 24-35 months. These results suggest that microbe-specific intervention strategies for the control of childhood diarrhoeal diseases in developing countries should focus on rotavirus, Shigella spp. and enterotoxigenic E. coli.

Effect of enterotoxigenic Escherichia coli heat stable toxin on intestinal lysosomal enzymes in the suckling rat.

A preliminary study on 9 suckling Wistar rats, which received E. coli stable toxin, and on 12 sham-operated controls showed that acid phosphatase, the marker enzyme for lysosome, was significantly increased in the infected group whereas alkaline phosphatase, glucose 6-phosphatase, succinic dehydrogenase, and proteinase, the marker enzymes for brush border, microsome, mitochondria, and the soluble fraction, respectively, remained unaffected. The results suggest that lysosome, the subcellular organelle responsible for intracellular digestion could be modified by E. coli stable toxin. In another set of experiments, where 7 infected suckling rats and 7 sham-operated controls were used, the maximal activities of lysosomal enzymes (released by Triton X-100) were found to be increased in the infected group confirming the results obtained in the preliminary experiment. The values of the ratio between maximal and basal activity (an expression of the degree of retention of enzymes to lysosome) of acid phosphatase and cathepsin D were also significantly increased, indicating that lysosomal membrane may also be stabilized during the infection. The increased activities of lysosomal enzymes and the increased lysosomal membrane stability suggest that intracellular digestion by lysosome could be increased during E. coli stable toxin infection.

Endotoxaemia in complicated falciparum malaria.

In a prospective hospital-based study, endotoxin was detected by amoebocyte limulus lysate test in the blood of 18 of 20 patients with complicated Plasmodium falciparum (16 with cerebral malaria, 2 with blackwater fever, one with acute malarial hepatitis and one with hepatorenal failure) and in all 5 patients with uncomplicated malaria tested, but in none of 5 healthy volunteers. There were 4 deaths among the 18 patients with complicated malaria and endotoxaemia. No correlation between endotoxaemia and presence of complications, clinical severity, or degree of parasitaemia was found. A concomitant bacterial infection could account for endotoxaemia in 11 of the 16 patients with cerebral malaria and endotoxaemia; in the other 5 patients with cerebral malaria, 4 with other complications, and 5 with uncomplicated malaria, endotoxin was detected in the blood without any evidence of bacterial infection.

Effect of boiled-rice feeding in childhood cholera on clinical outcome.

Forty-eight children, aged 2-5 years, presenting with watery diarrhoea of less than 48 h duration at home prior to hospitalization, were admitted into a randomized controlled clinical trial, 24 children being treated during the first 24 h of admission with oral rehydration solution (ORS) alone and 24 children being given 'ORS plus boiled-rice feeding'. The latter group received boiled-rice to supply at least 55 kcal/kg/d (about 150 g boiled-rice per feed, given four times daily). Vibrio cholerae were isolated by stool culture on admission from all children. No antibiotics were given. Clinical characteristics of children in the two treatment groups were comparable. Among children given 'ORS plus boiled rice', there was a significant increase in volume of diarrhoea stools (P less than 0.05), duration of diarrhoea in hospital (P less than 0.01), and more frequent diarrhoea motions (not significant statistically). However, the children fed boiled rice absorbed and retained 176 ml more fluid, and had gain in body weight comparable to that observed in children who were not fed during the first 24 h of hospitalization.

In vitro determination of intestinal amino acid (14C-L-glycine) absorption during cholera.

In vitro uptake of 14C-L-glycine was studied in jejunal mucosa biopsy specimens from 27 patients with cholera (proven by stool culture) presenting within 48 h of onset of watery diarrhea. In time series experiments, 14C-L-glycine uptake was found to follow saturation kinetics (being saturated at 5 1/2 min), to be blocked by uncouplers of oxidative phosphorylation (sodium fluoride and 2:4-dinitrophenol), and that 14C-L-glycine uptake by both amino acid transport system 1) and amino acid transport system 4) were active during the active purging stage of cholera. Concentration series experiments were carried out to determine the Vmax and Kt of these transport systems, which were not significantly different. This study demonstrates continued absorption of amino acids (glycine) by two amino acid transport systems, provides scientific basis for use of glycine in "improved" oral rehydration solutions in the treatment of acute diarrhea, and emphasizes the importance of maintaining feeding during acute diarrhea in order to prevent development of malnutrition.