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Biomedical subjects

E Lebenthal

Publications and source records attributed to E Lebenthal.

At least 109 records · Page 6Linked to original sources
PubMed1987

Adherence of Salmonella typhimurium to small-intestinal enterocytes of the rat.

The adherence of radiolabeled Salmonella typhimurium to freshly isolated enterocytes of rats was studied. The results established that type 1 fimbriated strains adhered in significantly higher numbers than did related nonfimbriated strains. Adherence was inhibited by D-mannose and methyl alpha-D-mannoside. Results of kinetic studies indicated that adherence was biphasic; the number of bacteria that adhered per enterocyte remained constant for approximately 20 min and then increased rapidly under the assay conditions. The second phase was associated with structural damage to the enterocytes. The addition of chloramphenicol did not prevent the initial attachment of bacteria to enterocytes but did prevent the second phase. Viable and nonviable bacterial cells adhered to enterocytes, but only viable bacteria were destructive. Freshly isolated enterocytes (trypan blue impermeable) and enterocytes stored overnight (trypan blue permeable) were infected by viable S. typhimurium in a similar manner, suggesting that metabolic activity of the host cell was of less consequence than metabolic activity of the bacterial cells. A model for the role of mannose-sensitive fimbriae as a virulence factor is proposed.

Animals↗
PubMed1987

Immunoglobulins A and G2a in milks of protein- and calorie-restricted dams.

It is well accepted that breast-feeding enhances the ability of newborns and infants to be protected against infection. Maternal nutritional status may affect this passive immunological defense mechanism because of either the change in the volume of milk or the alteration of the immunological components secreted in the milk. Diet restriction in lactating dams has been shown to influence the secretion of immunoglobulin in their milk. We investigated the specific role of caloric or protein restriction on immunoglobulin A (IgA) and IgG2a secretion in the milk of lactating rats. Both calorie- and protein-restricted dams had lower protein levels (milligrams per milliliter) than did the controls during the initial days of lactation (P less than 0.05). The levels (milligrams per milligram of protein) of IgA and IgG were higher in the milk obtained from calorie-restricted dams during the whole lactation period. The amount of IgA in the milk of protein-restricted rats was higher during 21 days of lactation, while the amount of IgG2a was higher only during the first 2 weeks of the lactation period compared with the respective values for the milk from control dams (P less than 0.05). Rats on a protein-restricted diet had lower IgA and IgG2a levels in their milk than those on a calorie-restricted diet at the second half of the lactation period (P less than 0.05). Our data suggest that the diet-restricted dams had a compensatory mechanism to ensure passive immunological protection for their pups during lactation. The compensation was diminished with a protein-restricted diet compared with a calorie-restricted diet.

Animals↗
PubMed1987

Postprandial glucose and insulin responses to glucose polymers by premature infants.

Previous studies have questioned whether neonatal infants can digest and absorb glucose polymers (GP). Thirteen infants of 33-42 weeks of corrected gestational age were fed two glucose polymers with different dextrose equivalents (DE) and glucose. Postprandial glucose and insulin responses were measured consecutively after each feeding. At 60 min, glucose, glucose polymer DE 15 and glucose polymer DE 24 produced serum glucose responses of 138.1, 111.6 and 120 mg/100 ml, respectively. Differences in mean serum glucose and insulin levels were found when glucose or glucose polymers were used as the test carbohydrate. Glucose polymer DE 24 produced a hormonal response closer to that of glucose. This suggests that glucose polymers were hydrolyzed and absorbed and evoked a sufficient glucose and insulin response. Therefore, these glucose polymers would seem to be suitable for use in feeding neonatal infants.

Blood Glucose↗
PubMed1987

Ontogenic changes in serum immunoglobulins and C3 in vitamin-D deficient and malnourished rats.

In both protein energy malnutrition and vitamin D deficiency, defects in some immunological functions have been noted, but the effects on complement and immunoglobulin concentrations have not been evaluated. We assessed the effects of malnutrition and vitamin D deficiency on immunoglobulins and C3 in rats in early postnatal life during weaning and early adulthood using the rocket immunoelectrophoresis technique. In well-nourished rats, the serum levels of IgG increased from 88.5 +/- 10.2 mg/dl in the newborn period to 883.4 +/- 104.8 mg/dl at weaning (day 19). The adult levels, 1,325.9 +/- 60.8 mg/dl, were attained by 35 days of age. Serum IgA was not detectable by our method until 20 days of age (1.1 +/- 0.2 mg/dl) and reached adult levels (13.4 +/- 3.2 mg/dl) by day 35. IgM was detectable in the serum of pups at 5 days of age (0.4 +/- 0.07 mg/dl), increased to 27.5 +/- 6.9 mg/dl at weaning and approached adult levels (93.7 +/- 9.9 mg/dl) at day 35. C3 levels at birth were only 36% of adult levels and did not change during the suckling period. They then increased to levels comparable to those of adults at the age of 35 days. Serum immunoglobulins and C3 in malnourished rats were not significantly different from age-matched control pups. In pups born to dams fed a vitamin-D-deficient diet from 3 weeks of age, only the serum IgG and C3 levels were significantly lower than those of normal pups at day 1 (IgG level: 65.2 +/- 6.1 vs. 88.5 +/- 10.2 mg/dl; C3 level: 20.3 +/- 6.9 vs. 36.2 +/- 3.1% of an adult level; p less than 0.005). Thus the increased susceptibility of malnourished young animals to infection does not appear to be related to a lowering of serum immunoglobulin and complement concentrations.

Aging↗
PubMed1987

The impact of development of the gut on infant nutrition.

We have described the developmental pattern of the GI tract, constituent tissues of which do not develop simultaneously, either functionally or morphologically. Dietary modifications to suit the stage of development have been described, and possible changes resulting from these modifications are also discussed. It is important to note that the newborn period is a time in which rapid development is taking place while the GI system is still not fully mature, hence the macro- and micronutrients given during this period should be adjusted both quantitatively and qualitatively to suit the needs of the infant, particularly so if he is premature or compromised.

Animals↗
PubMed1986

Interaction of epidermal growth factor with specific binding sites of enterocytes isolated from rat small intestine during development.

Isolated enterocytes from rat small intestine were characterized for their specific binding of epidermal growth factor (EGF). Intestinal epithelial cells were isolated at 4 degrees C to minimize the loss of receptor sites during the isolation procedure. 125I-labelled EGF binding to enterocytes from adult rats was found to be specific, saturable, temperature dependent and trypsin sensitive. Binding performed in the presence of a lysosomotropic agent (NH4Cl) increased the time required to reach maximal binding at 25 degrees C. NH4Cl had no significant effect on the time-course of EGF binding at 4 degrees C and 37 degrees C. A Scatchard plot showed a curvilinear relationship indicating that EGF binds to enterocytes with more than one binding site. Developmentally, enterocytes from fetuses and pups showed characteristic temperature dependence and trypsin sensitivity, but with different levels of binding to EGF. Specific EGF binding was demonstrably higher in enterocytes from small intestine of term fetuses. EGF binding to isolated enterocytes declined rapidly after birth, and the level stayed fairly constant thereafter. Pretreatment of enterocytes from fetal intestine with mature rat milk led to a dose-dependent decrease in EGF binding. These results suggest the presence of endogenous milk factors that modify EGF binding and account for, at least partly, the observed rapid decrease of EGF binding after birth.

Age Factors↗
PubMed1986

Acute starvation and suckling rat pancreas. Effect on exocrine pancreas and role of corticosteroids.

Starving of rat pups at the 5th or 10th day of life for three days led to lower body and pancreatic weights compared to age-matched controls. When compared to the weights before fasting, only the 5-day-old pups showed increases in pancreatic protein and DNA contents despite food deprivation. Pancreatic acinar responsiveness to carbachol stimulation was not affected. Accumulations of amylase and lipase in the pancreas of the rat pups were increased by fasting, with an accompanied surge in the level of serum corticosterone. In 10-day-old rat pups, injection with aminoglutethimide (AG), a drug which suppresses steroidogenesis, prevented the enzymatic increases and concomitantly suppressed the serum total corticosterone levels at 12 and 24 hr after the onset of fasting. These results strongly support the role of corticosterone in the modulation of the pancreatic adaptation to food deprivation in the suckling rat.

Aminoglutethimide↗
PubMed1986

Small intestinal mucosal hyperplasia caused by an enterokinase inhibitor from red kidney bean in rats.

A specific enterokinase inhibitor (EKI) was purified from red kidney bean (RKB). Male weanling rats fed a diet containing this purified EKI (0.06%) for 6 d showed increases in mucosal weights, protein, DNA and lactic dehydrogenase contents in their small intestines compared to age-matched control rats fed a standard diet. Total mucosal EK and disaccharidase activities were, however, decreased in EKI-fed rats. Thus, oral consumption of EKI from RKB led to small intestinal mucosal hyperplasia in rats. The mucosal hyperplasia observed in EKI-fed rats is not likely due to decreased turnover of mucosal proteins as a result of reduced luminal proteases since luminal contents of trypsin, chymotrypsin and elastase in EKI-fed rats were similar to those of control rats. Enterokinase inhibitor may have a direct hyperplastic effect on the small intestine of rats.

Administration, Oral↗
PubMed1986

Pancreaticobiliary factors in the modulation of small intestinal enterokinase in the rat.

Chronic pancreaticobiliary diversion was employed to study the modulation of enterokinase in the small intestine of adult rats. Diversion resulted in apparent trophic changes of the proximal bypassed portion of the intestinal mucosa. An almost complete loss of mucosal enterokinase activity in the proximal duodenum but no increase of enterokinase in the segments distal to reentry of the common duct was found in the pancreaticobiliary-diverted rats. The effect on the enterokinase activity in the proximal segment was specific in that no other brush-border enzymes measured in that segment were decreased. The decrease in enterokinase was partially prevented by dietary supplementation with pancreatic trypsinogen and completely avoided with the addition of a combination of bile acids and trypsinogen. Supplementation with bile acid alone did not preserve the enterokinase levels in the bypassed rats. The results suggested that trypsinogen is the primary factor responsible for modulating enterokinase levels in the proximal small intestine, with bile acids acting as a modifier.

Animals↗
PubMed1986

Ontogeny of pepsin secretory response to secretagogues in isolated rat gastric glands.

By use of isolated gastric glands from rats at various ages, we demonstrated that full-term neonate and 1-day-old rats showed no response to cholecystokinin octapeptide (CCK-OP), carbachol, or Ca2+ ionophore. The same glands, however, were responsive to dibutyryl cAMP. A mature response was not found until the pups were 2 days old. Injection of hydrocortisone into newborn rats led to an increase in pepsinogen concentrations in gastric glands and also an increased responsiveness to CCK-OP, carbachol, and Ca2+ ionophore A23187 24 h after administration. Hydrocortisone thus caused precocious maturation of both pepsinogen accumulation and pepsinogen secretory responsiveness of gastric glands in rat pups.

Animals↗
PubMed1986

Maturation of cholecystokinin receptors in pancreatic acini of rats.

Amylase secretion by fetal and newborn rat pancreata was shown not to respond to cholecystokinin (CCK) stimulation. Binding of 125I-Bolton-Hunter (125I-BH)-CCK-8 to dispersed pancreatic acini from rats at various perinatal ages was measured and compared with adults. Binding occurred maximally at 30 min at 37 degrees C at all ages. Maximal binding increased with age. The capacity and affinity of the CCK-receptor binding system was analyzed by Scatchard's method. The results revealed that the capacity of the high-affinity component gradually increases with age, whereas that of the low-affinity component remains relatively constant. Amylase secretion due to CCK stimulation also increases with age, suggesting that the lack of responsiveness of pancreata of pups to secretagogue is due to a low binding capacity of the high-affinity component of the receptors.

Aging↗
PubMed1986

Effect of nutritional rehabilitation on the development of intestinal brush border disaccharidases of postnatally malnourished weanling rats.

The reversibility of the effects of postnatal malnutrition on the intestinal brush border enzymes and somatic and intestinal weights were examined using either ad libitum or restricted feedings. Malnutrition was induced in the immediate postnatal period by expanding newborn rat litters to 20 pups/dam. At 21 days of age, malnourished pups exhibited significantly decreased body and intestinal weights as compared to those from control litters. Malnourished pups also had significantly elevated lactase specific activities whereas sucrase and maltase activities were not affected in the proximal small intestine. With subsequent nutritional rehabilitation by an ad libitum (food available 24 h/day) or restricted feeding regimen (food available 2 h/day), body and intestinal weights remained significantly depressed by 56 days in malnourished as compared to control animals. Rats on 2-h feedings consumed approximately 35% of the food consumed by their ad libitum-fed counterparts. Comparison of the ratio of weight gained to the amount of food consumed did not demonstrate a greater food efficiency with any particular feeding pattern. With ad libitum or restricted feedings, lactase specific activity in the proximal segment attained control values by 14 days. Restricted feedings resulted in an apparent elevation of specific activity of sucrase and of maltase, when rats were sacrificed at one chosen time point. Multiple time studies in a 24-h cycle showed that maximal elevations in enzyme activities were associated with feeding time. There were no significant differences in mean specific daily enzyme activities between the two feeding regimens. Restricted feedings show no advantage in enzyme efficiency or in promoting the rate of recovery of the intestine after postnatal malnutrition.

Animals↗
PubMed1986

Enteral feedback control of pancreatic hypertrophy: the role of pancreatic biliary secretions.

Chronic diversion of pancreatic and biliary secretions away from the proximal small intestine resulted in rapid increases in pancreatic size and protein content in adult rats. The effect was detectable as early as 10 days postsurgery. Differential changes in pancreatic enzymes were evident after bypass. The concentration of trypsinogen remained stable while amylase concentrations showed a marked decrease. Total pancreatic trypsinogen content, however, was increased, while amylase content remained similar to controls. Feeding bypassed rats with chows containing various pancreatic and biliary supplements had no effect on the hyperplastic response of their pancreata. Trypsinogen and amylase levels in supplemented groups remained similar to the bypassed group fed nonsupplemented chow, with the exception of increases in trypsinogen concentration and content in the groups supplemented with bile and cotazyme plus bile acids. The adequacy of oral refeeding of pancreatic biliary components was supported by its effectiveness in restoring mucosal enterokinase activity and trypsin levels in segment 1. However, there was no correlation between tryptic activity in the contents of the bypassed segment and the eventual pancreatic weight. These results indicate that factors other than those supplemented in this study are required in maintaining the steady state of pancreatic growth in normal rats.

Ampulla of Vater↗
PubMed1986

Carbohydrate digestion: development in early infancy.

Developmental, congenital, and acquired carbohydrate malabsorption syndromes and the particular problems of premature and compromised infants are presented. The clinical features, pathogenesis and intervention strategies for the aforementioned disorders are reviewed.

Amylases↗
PubMed1986

Computed axial tomographic scanning of the thigh: an alternative method of nutritional assessment in pediatrics.

In this study we compared the findings of computed axial tomographic (CT) scanning of the thigh with the findings of arm anthropometry and urinary creatinine determinations to assess nutrition in children with inflammatory bowel disease receiving total parenteral nutrition. All 14 children received our standard solution for total parenteral nutrition as well as prednisone and sulfasalazine (Azulfidine) therapy. All patients were assessed by arm anthropometry, 24-hour urine collections for creatinine clearance, and CT scanning of the thigh during total parenteral nutrition. Arm muscle and fat area were estimated by anthropometry, and those in the thigh were estimated by CT scanning. Our results show the total muscle area from the CT scan can predict muscle mass calculated from the urinary creatinine excretion rates. In addition, there is a close correlation between the thigh muscle area as measured by CT scanning and the muscle area calculated from urinary creatinine excretion rates. In addition, the comparison of thigh muscle area and thigh fat area to the midarm muscle area and midarm fat area, respectively, showed that the thigh is a better predictor of muscle than fat in the midarm. We conclude that the total thigh muscle area is a better predictor of muscle mass as compared to the midarm muscle area. In addition, the CT scan cut at the level of the thigh in children and adolescents with inflammatory bowel disease can provide valuable information about the thigh compartment and analyses of different cross-sectional areas of the thigh.

Adolescent↗