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Salsify (Tragopogon porrifolius) and gobo (Arctium lappa) are root vegetables that contain high concentrations of naturally occurring fructooligosaccharides (FOS), nondigestible oligosaccharides that have prebiotic effects on the intestinal microflora. The objective of this study was to compare colonic microbial populations and the fermentation characteristics of gobo and salsify in breast-fed vs. formula-fed infants. Fecal inoculum from breast-fed and formula-fed infants consuming either no solid foods, cereal, or fruit and vegetable purees were fermented in vitro with sweet potato puree plus gobo, salsify puree or a control vegetable, carrot. Breast-fed and formula-fed infants had similar fecal bacteria concentrations, with the exception of Clostridium perfringens (P < 0.10). Introduction of solid foods into the diet of infants was associated with increased fecal concentrations of bifidobacteria (P < 0.10) and decreased concentrations of total aerobes (P < 0.01), C. perfringens (P < 0.001) and Escherichia coli (P < 0.10). Inoculum from feces of breast-fed infants resulted in greater acetate production, whereas inoculum from feces of formula-fed infants resulted in greater propionate and butyrate production (P < 0.05). Fermentation of FOS-containing vegetables by infant fecal inoculum did not differ significantly from fermentation of carrots as assessed by total short-chain fatty acid (SCFA) production. The addition of solids to the diet of infants was associated with increased production of acetate and total SCFA (P < 0.05). It appears that both the composition and fermentative activity of the colonic microflora of human infants is affected by breast-feeding and solid food consumption, but not by short-term exposure to low concentrations of FOS-containing substrates.

Formula-fed infants have depressed plasma tryptophan concentration relative to human milk-fed infants. Because tryptophan alters sleep-waking patterns in adults, a study was designed to determine whether additional dietary tryptophan could elevate plasma tryptophan concentrations of formula-fed infants to concentrations characteristic of human milk feeding and whether differences in plasma tryptophan or the ratio of plama tryptophan to the sum of the other plasma large neutral amino acids (tryptophan:LNAA) were of behavioral significance. Infants were fed a formula (13 g protein/L; whey:casein, 34:66) containing either 0, 294, 588 or 882 mumol/L of added tryptophan. Infants fed human milk or commercial formula (15 g protein/L; whey:casein, 18:82) were included for comparison. In formula-fed groups, plasma tryptophan was directly related to tryptophan intake (r = 0.46, P less than 0.0005). Infants fed commercial formula or the formula without added tryptophan had lower (P less than 0.001) plasma tryptophan compared with infants fed human milk. Only the infants fed the highest tryptophan formula had significantly higher plasma tryptophan:LNAA ratios than the other experimental groups, and these ratios were similar to those of infants fed human milk. The plasma tryptophan:LNAA ratios, not plasma tryptophan concentrations, were predictive of differences in the infants' sleep latency; infants fed formula containing the highest tryptophan had sleep latencies of 18.7 min, significantly shorter (P less than 0.05) than those of infants fed formulas containing less added tryptophan (27.7 min). Feeding infants formulas differing in tryptophan concentration produced differences in sleep latency, which could influence neurobehavioral developments.(ABSTRACT TRUNCATED AT 250 WORDS)

Alterations in pancreatic function and structure were examined in suckling mice infected intraperitoneally with reovirus type 3. The results were compared to pancreatic zymogen enzyme activities and histology in adult mice infected with the same virus. No effect of the rovirus type 3 on the adult mice could be elicited. In contrast, the suckling mice infected by the reovirus type 3 revealed a definite change in pancreatic zymogen enzymes. However, the zymogen enzymes were affected in a nonparallel fashion and three groups of enzymes with different responses were noted. Amylase and lipase activities were significantly diminished (P less than 0.001) at 6 days of viral infection. The endopeptidases, trypsin (P less than 0.025) and cymotrypsin (P less than 0.001) activities were increased significantly in the infected group. The exopeptidases, carboxypeptidase A and B in the infected animals were not changed significantly compared to the control. It seems reasonable that the reovirus type 3 infection in the suckling mouse causes diminished lipase and amylase activities that might contribute to the pathogenesis of viral enteritis.

Hyperaminoacidemia is evident in infants fed either whey-dominant or casein-dominant formula containing 2.2 g protein/100 kcal. We assessed protein metabolism in infants fed formulas with reduced protein contents and various whey/casein ratios. Term infants (n = 40) received either human milk or formula containing 1.8 g protein/100 kcal and whey/casein ratios 18:82, 34:66, or 50:50. At ages 4 and 8 weeks, growth indices and mean serum concentrations of retinol binding protein, albumin, total protein, and serum urea nitrogen were similar, as were mean plasma concentrations of total amino acids, total essential amino acids, and their ratio. Compared with infants fed human milk, those fed formula had plasma concentrations similar for valine, lysine, arginine, tyrosine, histidine, threonine, and free and total cyst(e)ine; elevated for phenylalanine, methionine, and citrulline; and depressed for taurine and tryptophan. Except for leucine, mean plasma amino acid values varied similarly among formula groups despite differences in intakes. Our data indicate that feeding formulas providing 1.8 g protein/100 kcal results in many indices of protein metabolism characteristic of human milk feeding. However, certain differences are noted, suggesting the need for further manipulation of specific amino acid patterns of infant formulas.

A leukemic mouse model was employed to elucidate the separate effect of leukemia and cytotoxic drugs on the jejunal mucosa and its associated digestive enzymes. The mitotic activity, depth of the crypt and villus-crypt quotient were not significantly changed in leukemic mice in comparison to normal mice. The mitotic activity and the depth of the crypt 48 h after 20 mg methotrexate (MTX)/kg were significantly reduced (p less than 0.01) in leukemic mice. Sucrase (p less than 0.001) and maltase (p less than 0.025) activities in the jejunum from leukemic mice were significantly elevated in comparison with non-leukemic controls. In both non-leukemic and leukemic mice, the dose-response curves for MTX administration revealed a significant decrease and a nadir in sucrase (p less than 0.001) and maltase (p less than 0.0025) activities at the dosage of 20 mg/kg. Thus, in the mouse model, leukemia per se does not contribute to significant diminution in small intestinal function. In the small intestine, MTX appears to be responsible for a decrease in the mitotic activity of crypt cells, depth of the crypt and diminished sucrase and maltase activities.

Relationships between intakes of amino acids and total nitrogen, and blood indices of protein utilization were studied in 37 term infants fed either human milk, whey-predominant formula, or cow's milk formula as the sole nutritional source for 8 weeks. Biochemical analyses of two-hour fasting blood samples, and intakes calculated using three-day dietary records and direct analyses of milk samples were used to evaluate these relationships. Intakes of total nitrogen were positively correlated with plasma valine, leucine, isoleucine, phenylalanine, and serum urea nitrogen concentrations (r = .46 to .62, P less than .01 to .001). Intakes of the four amino acids whose plasma concentrations were positively correlated with total nitrogen intakes plus four additional amino acids (threonine, tyrosine, histidine, and methionine) were correlated with their respective plasma concentrations (r = .41 to .74, P less than .01 to .001). These relationships have not been previously described in term infants. Compared with values in infants fed human milk, plasma concentrations of valine, phenylalanine, methionine, and serum urea nitrogen were elevated with whey-predominant formula and cow's milk formula feeding. Values for four additional amino acids (threonine, lysine, leucine, and isoleucine) were elevated with whey-predominant formula feeding. Data indicate that altering the whey-to-casein ratio and, thus, the amino acid pattern of formulas will not achieve the desired blood indices characteristic of human milk feeding without a reduction in the total nitrogen content of formulas.

Chronic retentive constipation in children is common, often undertreated, and frequently resistant to standard treatment. A new understanding of abnormal defecation dynamics has evolved to complement the established medical behavior model of this condition. The primary care pediatrician is in an excellent position to facilitate prevention through counseling on normal bowel habits and early intervention. A comprehensive medical behavior intervention program can be supervised effectively by the pediatrician providing benefit to most patients. Those who are compliant with treatment and are resistant to intervention may benefit by extensive evaluation of anorectal dynamics and use of such teaching as biofeedback training.

The effect of undernutrition on rat small intestine during the critical newborn period was studied. A severe state of protein-energy malnutrition was induced by litter expansion which caused the mean total body weight of experimentally malnourished rats to diminish significantly as compared to control animals. Intestinal weight and total DNA were similarly diminished in the malnourished rats. DNA and protein expressed per gram wet tissue showed no significant differences between groups. Retarded intestinal growth in the malnourished animals was the result of reduced cell number. The mean specific activities of sucrase and maltase were diminished in the experimental group, with mean activities being 20 to 50% of controls, respectively. These differences were larger when expressed as total organ activities. On the other hand, specific lactase activity was significantly higher in undernourished rats but total lactase activity per organ was similar in both groups. Enterokinase specific activity or total organ activity was significantly higher in the undernourished rats.

Suckling mice infected with reovirus type 3 were examined for changes in the epithelial brush border of the small intestine. After 3 days of infection with reovirus type 3, no significant changes were found in intestinal morphology or activity of any enzymes tested. After 6 days, villi were shortened and blunted with lymphangiectatic lesions and mild mononuclear infiltration in the lamina propria. In addition, there was a significant decrease in lactase (P < 0.001) and enterokinase activity (P < 0.05). However, there were no significant changes in the activities of alkaline phosphatase. In contrast, maltase (P < 0.001) and leucine aminopeptidase (P < 0.05) activities in the infected mice were significantly increased. These data suggest that brush border enzymes are affected differently by reovirus infection.

Whether prolonged cholestasis is followed by hepatic cirrhosis is still controversial. We have studied two unrelated children who have had cholestasis for 15 years, but neither of whom have developed cirrhosis. Both have severe growth retardation, peculiar facies, pulmonic stenosis, transitory renal tubular acidosis, and vitamin D-resistant rickets. The patients presented in infancy with hepatomegaly and direct hyperbilirubinemia; liver biopsy at that time revealed cholestasis and paucity of bile ducts. Subsequent serial liver biopsies have continued to demonstrate cholestasis, but there has been no evidence of cirrhosis. Electron microscopy has revealed swollen and blunted microvilli of the canalicular membrane of the hepatocyte. The patients have had elevated bile acids in the serum as well as a reversed ration of tri- to dihydroxy bile acids. Treatment with cholestyramine and phenobarbital has brought about symptomatic relief from severe pruritus and excoriation and has lowered the level of serum bile acids, although they are still above the normal range. These findings suggest that cholestasis accompanied by an elevated and reversed bile acid ratio does not universally cause hepatic cirrhosis.

Recognized limits of permissible exposure to hazardous airborne substances adopted by different countries for industrial health protection may differ by a factor of 10. A Joint ILO/WHO Committee on Occupational Health in 1969 was unable to recommend a single set of values as international standards for more than a few toxic agents. The greatest differences are in the tolerance limits employed in the USA and in the USSR. The reasons for this substantial disagreement are discussed in this paper and are explained in terms of fundamental differences in the psychophysiological criteria employed to establish safe limits between the maintenance of good health and the development of a significant threat to the health. Some practical implications in the selection of permissible limits of exposure by developing countries are discussed in relation to living standards, endemic disease, climate, and geographical situation.