SUMMARYBackground: The use of over-the-counter antacids has increased in children under the age of 12 years, and has been followed by an apparent increase in the use of over-the-counter histamine-2 receptor antagonists. However, the pharmacokinetic and pharmacodynamic effects of over-the-counter histamine-2 receptor antagonists in the paediatric population are largely unknown. Aim: To evaluate the pharmacokinetics and pharmacodynamics of a single dose of the over-the-counter histamine-2 receptor antagonist, ranitidine, 75 mg, in children with symptoms of gastro-oesophageal reflux disease. Methods: Children aged between 4 and 11 years with symptoms of heartburn suspected to be due to gastrooesophageal reflux disease were recruited at six clinical centres. Following a single dose of either oral ranitidine,

We conducted a randomized, double-blind trial evaluating the efficacy and safety of meperidine 2 mg.kg-1 (M) and meperidine 2 mg.kg-1 plus midazolam 0.05 mg.kg-1 (M + M) in 40 pediatric outpatients (age 1 to 17 years) undergoing upper endoscopy procedures. The physician and nurse performing the procedure were asked to rate cooperation, emotional status, drowsiness, and overall efficacy. A blinded observer recorded the frequency of negative behaviors indicating distress, vital signs, and oxygen saturation before, during, and after the procedure. No significant differences were noted in the overall efficacy of the regimens. Good or excellent efficacy was noted in 15 of 21 children (71%) in the M group and 15 of 19 children (79%) in the M + M group by physicians; nurses assigned a good or excellent rating for 14 of 21 (67%) and 13 of 19 (68%) in the M and M + M groups, respectively. Immediately following the procedure, amnesia was noted in 4 of 17 (23%) patients who received M versus 14 of 18 (78%) patients who received M + M (P = 0.002). Of the children who received M + M, the amnesia tended to occur more frequently in older children (> 11 years, 8 children, rate of amnesia 100%) than in younger children (< or = 11 years, 6 of 10 evaluable children, rate of amnesia 60%). There was no significant difference between the frequency of negative behaviors, rate of adverse effects, or changes in vital signs or oxygen saturation noted with the two drug regimens.(ABSTRACT TRUNCATED AT 250 WORDS)

ABSTRACT. Short-chain fatty acid production and assimilation is unlikely to occur a t significant levels in the newborn because the colon at birth is sterile, and only gradually acquires an anaerobic flora. This study profiled short-chain fatty acid levels in the colon lumen over the initial 21 days of life. Fecal samples were removed surgically from the cecum, right, and left colon from 36 York piglets, 0-21 days of life. Samples were subjected to in vitro dialysis and centrifugation methods to quantitate fecal water short-chain fatty acids, electrolytes, osmolality, and pH. A three-way analysis of variance examined piglet age, colon site of fecal samples, and method of fecal water analysis, for each variable. No differences were found between techniques of fecal water collection. Newborns showed production of short-chain fatty acids a s early a s the 1st day of life in limited amounts. Levels were stable between days 5 and 14, and then abruptly accumulated in the lumen. Acetate was predominant early, with propionate and butyrate responsible for late peaks. The production and assimilation of short-chain fatty acids was nearly complete proximal to the left colon. Age and colon site showed significant interactions for each fatty acid (p < 0.001). The combined osmolar contributions of short-chain fatty acids and electrolytes accounted completely for the luminal osmolality after the 2nd wk of life. Previously there was an "osmolar gap" suggesting that lactose or its breakdown products were present in the lumen and were being removed by pathways other than through short-chain fatty acid production. (Pediatr Res 22:720-724, 1987) Abbreviations SCFA, short-chain fatty acids CEN, centrifugation DIA, in vitro dialysis POST-DIA, postdialysis centrifugation ANOVA, analysis of variance ip, intraperitonealThe passage of carbohydrates across the ileocecal valve is a normal phenomenon throughout life. A metabolic pathway for carbohydrate digestion in the colon has been well established (1). In the anaerobic environment of the colon, fecal organisms ferment carbohydrate to gasses (H2, C02, CH4) and SCFA (acetate, butyrate, and propionate). The presence of SCFA is critical to the normal physiology of the colon. SCFA absorption from the lumen of the colon is rapid and efficient, and their

ABSTRACT. The unidirectional flux of 10-and 40-mM lactose was studied in newborn porcine jejunum and colon mounted in Ussing chambers. Polyethylene glycol 400 was used to measure passive paracellular permeability. The mucosal-to-serosal flux and the tissue accumulation of labeled lactose from the colon was similar to that of lactosederived glucose from the jejunum. However, only jejunum showed a lactose-stimulated increase in short-circuit current. In jejunum, glucose was the sole sugar identified in the serosal bath, whereas in colon, only intact lactose was identified. Despite colonic lactose flux, polyethylene glycol oligomers were not found in the serosal bath, suggesting that they do not share the same route of absorption. Colonic lactose transport was nonsaturable between 1 and 40 mM. Under nongradient conditions, no net colonic lactose transport was observed. Cumulatively, these data suggest that the colon, unlike the jejunum, does not contain a glucosegalactose sodium cotransporter. The colon of the newborn piglet transports intact lactose at a flux equal to that of Several studies (1-5) have suggested that the colon of the human neonate, especially the premature infant, may be a major site for the digestion and assimilation of lactose. Estimates of the amount of lactose retrieved from the colon in newborns vary. Based on breath Hz measurements in human premature infants, estimates by MacLean and Fink (3) suggested that most of the ingested lactose was fermented in the colon. Subsequently, data on the rate of Hz recovery in the breath of infants after a lactose meal led to a revision of MacLean and Fink's estimates and suggested that the amount of lactose fermented may be 15 to 20% of that ingested (6). Because the daily lactose load is substantial (nearly 13 g/kg/d), the amount passed into the colon could be nutritionally significant. Surprisingly, the newborn nei- 5ther develops an osmotic diarrhea nor loses excessive amounts of carbohydrate in the stool (2,4, 5). Based on the available data, researchers have inferred that, as in adults, bacterial fermentation is the primary mechanism whereby the newborn salvages lactose energy that would otherwise be lost (7).However, it has been shown that even when colonic bacterial population is low, the newborn can still recover lactose from the lumen of the colon. In vivo colonic perfusions in newborn piglets, in which the bacteria had been depleted by flushing with normal saline, demonstrated that the colonic mucosa absorbs the lactose at a rate up to 20-fold greater than it absorbed an equimolar mixture of glucose and galactose, the monosaccharide constituents of lactose (8). This phenomenon was not the result of prior action of bacterial or colonic mucosal P-galactosidase activity; both were shown to be negligible.In the current study, lactose uptake was compared in the jejunum and the right colon of the newborn piglet using tissues mounted in Ussing-type chambers. J, , , and appearance of carbohydrate in the serosal bath were determined, and measurements of ...