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Biomedical subjects

E Lebenthal

Publications and source records attributed to E Lebenthal.

At least 145 records · Page 8Linked to original sources
PubMed1983

Impact of development of the gastrointestinal tract on infant feeding.

We have described the developmental pattern of the gastrointestinal tract under optimal conditions (i.e., low risk pregnancy and normal labor and delivery at term). The tissues do not develop simultaneously, and morphologic and functional development are not concurrent. An important consideration is the effect of suboptimal or even adverse conditions on the developmental sequence and attainment of maturity. Malnutrition during both the prenatal and postnatal periods may restrict the morphologic and biochemical development of the gastrointestinal tract. Dietary modifications have been shown to alter the developmental pattern of intestinal and pancreatic enzymes in animal models. Drugs and hormonal therapy given during pregnancy and early infancy have been known to cause developmental defects, but the specific effects on the gastrointestinal tract have not been evaluated. For further understanding of digestibility of nutrients and absorption in the perinatal period, these departures from the normal development of the gastrointestinal tract and the mechanisms by which these potential effects occur remain to be described. In view of these undetermined factors, in the case of intolerance or unavailability of milk from the natural mother, feedings should be individualized, with attention to direct measurement of enzyme concentrations, balance studies, or both, especially in the case of extreme prematurity or unusual requirements.

Dietary Carbohydrates↗
PubMed1983

Corn syrup sugars: in vitro and in vivo digestibility and clinical tolerance in acute diarrhea of infancy.

We evaluated the in vitro and in vivo digestibility and clinical tolerance of three corn syrup sugars (DE10, 15, 24) and one infant formula containing corn syrup sugar as the sole carbohydrate source (DE24). In vitro studies were conducted using human duodenal fluid and jejunal mucosa with normal enzyme activities. In vivo studies included intragastric perfusion studies and tolerance tests using the corn syrup sugars and a clinical formula trial in 32 infants with acute diarrhea. Results of the in vitro studies showed that each of the corn syrup sugars was well hydrolyzed by duodenal fluid and by mixtures of duodenal fluids and mucosal homogenates. Similarly, in vivo studies revealed significant hydrolysis in the proximal intestine, as measured during the perfusion studies, and adequate absorption, as indicated by a rise in serum glucose concentration during tolerance tests. Only patients who had a marginal serum glucose rise after a glucose meal had a blunted rise after a corn syrup feeding. More than 85% of the infants beginning the clinical trial tolerated the formula well and gained weight at or above the expected rate for age during the study interval. These data indicate that, except with severe mucosal injury and secondary monosaccharide intolerance, glucose polymers of the dextrose equivalents tested are suitable carbohydrate sources for infants recovering from acute diarrhea.

Clinical Trials as Topic↗
PubMed1983

Intractable diarrhea of infancy. An alternative treatment strategy.

Prolonged diarrhea in an adult is a serious problem; in an infant it is life threatening. Conventional therapy for intractable diarrhea of infancy, which involves use of clear liquids and gradual reintroduction of cow's milk or formula, works in most situations. However, for some infants this type of management exacerbates diarrhea. As alternative therapy, the authors recommend use of oral elemental diets in most infants and total parenteral nutrition in some. This would lessen the likelihood of diarrhea exacerbation and decrease morbidity and mortality.

Chronic Disease↗
PubMed1983

Role of corticoids independent of food intake in premature increase of pancreatic enzyme activities following early weaning in rats.

The effects of early weaning and food deprivation on the development of pancreatic exocrine enzymes were compared in a rat model. Suckling rats, 15 days old, were weaned onto powdered laboratory diet. Within 24 hours, early weaned rats increased their pancreatic enzyme activities with amylase increased to twice that of the continuous suckling nonweaned littermates. During this period, early weaned rats lost weight and pancreatic growth ceased. Suckling rats of the same age (15 days old), when fasted or injected with hydrocortisone had similar increases in pancreatic enzyme activities within 24 hours. Serum corticosterone levels were increased in early weaned and fasted rats to three to four times that found in continuously suckling littermates. An additional 48 hours of treatment (up to day 18) maintained the high pancreatic enzymes in fasted and early weaned rats. These results show that the increase in pancreatic enzyme activities following early weaning was independent of food intake. The close relationship between serum corticosterone levels and pancreatic enzyme activities together with the ability of hydrocortisone to induce pancreatic enzyme concentrations in pups of the same age suggests the involvement of corticosteroid as a mediator of pancreatic development in early weaning. These experiments demonstrated the importance of endocrine factors in the pancreatic "adaptive" response to early weaning in the rat, and further emphasized the importance of evaluating endocrine changes following any nutritional alterations during the development period.

Age Factors↗
PubMed1983

Mammary amylase: a possible alternate pathway of carbohydrate digestion in infancy.

Mammary amylase is a possible alternate pathway of digestion of glucose polymers and starches, that is most important in early infancy when pancreatic amylase is low or absent in duodenal fluid and responds poorly to stimuli. Human breast milk contains 1000-5000 units of amylase/liter. In order to evaluate the likelihood that a significant proportion of mammary amylase activity would withstand passage through the stomach, purified and unpurified mammary amylase were exposed to acid and pepsin in vitro to simulate the gastric environment found in young infants. Both purified and unpurified enzymes were stable at pH 7.5 with little or no activity lost after 4 h, and approximately 80% retained at 6 h. When incubated at pH 3.5, one-third of unpurified enzyme activity was retained for 6 h; in contrast, the purified enzyme was acid labile losing 80% by 2 h. Addition of bovine serum albumin or breast milk proteins to purified enzyme protected the activity. When unpurified enzyme was exposed to a stepwise decline in pH from 6.5 to 3.5 over 4 h, 50% of the original activity was retained. Unless the concentration was greater than or equal to 3750 units/ml, the addition of varying concentrations of pepsin to defatted breast milk incubated at pH 3.5 did not affect any greater decay of enzyme activity despite evidence of peptic digestion of proteins in the reaction mixture. This study supports the possibility that ingested mammary amylase could retain a significant proportion of its original activity after exposure to acid and pepsin in the stomach of young infants.

Amylases↗
PubMed1983

Early weanling and precocious development of small intestine in rats: genetic, dietary or hormonal control.

Small intestinal development was followed in rats from 17 to 28 days of age in order to evaluate the interactions of diets, genetic preprogramming, and hormones in influencing developmental changes. Control pups, weaned naturally at 21-24 days, showed a gradual increase in body weight, intestinal length, and segmental mucosal weight, total DNA, and protein content. In contrast, pups weaned at 17 days showed an immediate increase in intestinal length, decrease in lactase, and precocious increase in sucrase and maltase. The changes in segmental mucosal weight, DNA and protein contents, however, paralleled that of controls. Pups nursed up to 25 days had a smaller body weight, shorter intestine, lighter mucosa, and lesser mucosal protein content. They showed no significant delay in the increase in sucrase and maltase together with a persistent higher level of lactase. Enterokinase and leucine aminopeptidase showed little change irrespective of the dietary modifications. Significant increases in segmental mucosal mass, DNA, and protein contents during the studied period were seen in all animals. At 19 days, early weaned pups had serum levels of corticosteroids about 3 times that of control or prolonged nursed pups. The results support the concept of an inherent biologic program as a basic control of intestinal ontogeny whereas dietary changes seem to have a modifying role and act directly, or in concert with, hormonal changes.

Adrenal Cortex Hormones↗
PubMed1983

Effect of feeding regimens on the functional recovery of pancreatic enzymes in postnatally malnourished weanling rats.

Malnutrition was induced in the immediate postnatal period by expanding newborn litters to 20 rat pups/dam. The reversibility of the effects of malnutrition on the pancreas was evaluated by comparing two different feeding methods. At 21 days of age, pups from the expanded litters exhibited significantly decreased body (P less than 0.0005) and pancreatic (P less than 0.0025) weights as compared to those from control litters (12 pups/dam). Malnourished pups also had less contents of amylase (P less than 0.01), lipase (P less than 0.0005) and trypsinogen (P less than 0.0025) in their pancreases. The concentrations (specific activities) of amylase (P less than 0.05) and lipase (P less than 0.0125) were significantly decreased but trypsinogen (P less than 0.35) was not affected. Subsequent nutritional rehabilitation by an ad libitum (food available 24 h/day) or restricted (food available 2 h/day) feeding regimen failed to allow for "catch-up" in body (P less than 0.025) and pancreatic weight (P less than 0.05) by 56 days of life. With ad libitum feedings, enzyme contents and concentrations of amylase and lipase in malnourished animals attained control values by 7 and 14 days, respectively. Restricted feedings, however, delayed the recovery in amylase by an additional 7 days but lipase remained depressed in both content, (P less than 0.005) and specific activity (P less than 0.0025) for the duration of the experiment (56 days). Changes in pancreatic enzymes in response to malnutrition are readily reversible with ad libitum feedings but changes in somatic and pancreatic weights were not reversed.(ABSTRACT TRUNCATED AT 250 WORDS)

Amylases↗
PubMed1983

Amylase in the saliva and in the gastric aspirates of premature infants: its potential role in glucose polymer hydrolysis.

Amylase activity was found in saliva from 13 infants, 26-42 wk corrected gestational age. The levels of salivary amylase activity increased with advancing age. In 10 infants, 31-38 wk corrected gestational age (estimated gestational age in wk plus age in wk after birth), gastric aspirates collected before a feeding and sequentially at 30-min intervals after two consecutive feedings were analyzed for amylase activity and pH. Two different postprandial patterns were obtained. For six of the 10 infants, both the pH and amylase activities of their gastric aspirates showed a distinct maxima at about 60 min after a feeding and a minima at 180 min just before the second feeding. In the remaining four infants, the pHs of their gastric aspirates remained relatively high (5.0-6.0) for the entire postprandial period. In these infants, there was a persistently high level of the amylase activity. In all 10 infants, amylase activity was found in their gastric aspirate samples when the pH was above 3.0. Comparison of the amylase in the gastric aspirate with purified pancreatic and salivary amylases by polyacrylamide gel electrophoresis showed that the amylase in the gastric aspirate has an electrophoretic mobility similar to that of salivary amylase, which suggests a salivary origin. This study supports the possibility that salivary amylase could enter the stomach and retain a significant amount of its activity in premature infants.

Amylases↗
PubMed1983

Effect of glucose and insulin on small intestinal brush border enzymes in fasted rats.

Fasting reduced small intestinal length. It also decreased mucosal weight, DNA and protein content, and concentrations of enterokinase, maltase, and sucrase in both duodenal and jejunal segments. In contrast, the concentrations of lactase and leucine aminopeptidase were not affected. Concomitantly, serum insulin levels dropped to one-fifth of the control levels while serum glucose concentrations showed a lesser degree of reduction. Glucose supplementation alone raised the serum insulin level, prevented the decrease in DNA content, and showed a protective effect on mucosal protein, mucosal weight, mucosal thickness, and villus height. Glucose also protected the sucrase and maltase concentrations; more significantly for maltase in the jejunal segment. Insulin alone, although it increased the serum insulin level to that found with glucose supplementation alone, had no protective effect on the loss in protein, DNA, and most enzymes except for maltase concentration in the jejunal segment. Addition of insulin to glucose did not modify the glucose effect on the contents of DNA, protein, and concentrations of sucrase and maltase. These results suggest that the glucose effect on the mucosa is not mediated by insulin. In addition, the retention of both maltase and sucrase activities through only glucose supplementation suggests the loss of maltase and sucrase in fasting is due to nutrient rather than specific substrate restriction.

Animals↗
PubMed1983

Isolated congenital enterokinase deficiency. Recent findings and review of the literature.

We report a 13-mo-old patient with isolated congenital enterokinase deficiency and review the clinical features, diagnostic approach, and management of all 8 reported patients. Our patient presented with failure to thrive, diarrhea, and hypoproteinemia since birth. A normal sweat chloride with small intestinal histology, and nondetectable trypsin activity in the duodenal fluid should alert the physician to the possibility of isolated enterokinase deficiency. All reported patients, including our own, responded favorably to pancreatic enzyme replacement. In vitro studies of the small intestinal mucosal biopsy specimen suggest that enterokinase deficiency at least in part is due to altered enzymes with low enterokinase activity.

Diarrhea, Infantile↗
PubMed1983

IgE and IgD antibodies to cow milk and soy protein in duodenal fluid: effects of pancreozymin and secretin.

Duodenal fluid IgE was reported to be increased in food allergy and in inflammatory conditions of the bowel. We studied the presence and specificity of IgE and IgD antibodies against alpha-casein, beta-lactoglobulin A, alpha-lactalbumin, bovine serum albumin and soy bean agglutinin using an enzyme-linked immunoassay (ELISA). Thirteen children with various intestinal diseases and thirteen normal adult volunteers were examined. In resting duodenal fluids, 8/13 of the children had IgE and 5/13 had IgD, while only 1/13 of the adults showed detectable IgE and IgD. After pancreozymin, 4/6 of the children and 4/8 of the adults showed detectable IgE and IgD in their duodenal fluids. After secretin, the duodenal fluids from 1/8 of the children and 2/8 of the adults had detectable IgE, while 6/13 children and 1/10 of the adults had IgD. The results indicate an increase in duodenal contents of IgE and IgD antibodies specific to cow's milk and soy protein after pancreozymin. Since this mediator is normally released during digestion, it is suggested that IgE and IgD antibodies specific for food proteins, may be involved in the physiological processing of foods in the intestine. In infants and children with gastrointestinal disease, the incidence of IgE and IgD antibodies specific for milk and soy proteins is higher in basal and pancreozymin-stimulated duodenal fluid when compared with control adults.

Adolescent↗