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Biomedical subjects

E Lebenthal

Publications and source records attributed to E Lebenthal.

At least 73 records · Page 4Linked to original sources

High-fat semielemental diet in the treatment of protracted diarrhea of infancy.

The capacity for greater fat absorption relative to carbohydrate absorption in protracted diarrhea of infancy was studied in a developed and a developing country (Buffalo, NY, and Bangkok, Thailand). Fifty patients with protracted diarrhea in the first year of life (defined as liquid stools of more than 20 mL/kg per day with more than a 14-day duration) were randomly assigned to receive either a standard semielemental diet (Pregestimil) or a high-fat semielemental diet that contained 40% more fat. The increased fat was largely in the form of medium-chain triglycerides, with the new diet providing 60% of the fat as medium-chain triglycerides compared with 40% in the standard diet. Tolerance to both diets was good in both studies. Both groups showed adequate weight gain and an improvement in anthropometric and biochemical parameters. The patients receiving the high-fat diet showed no initial weight loss, however, and their weight gain was initiated earlier. Cumulative weight gain was also higher in the group receiving the high-fat semielemental diet. Fecal fat analyses were performed after 1 week of therapy. There was no difference observed in the coefficient of fat absorption between the groups receiving the two formulas, indicating that infants with protracted diarrhea may be able to tolerate a higher fat intake than is normally provided. As carbohydrate intolerance is known to be a complicating factor when using semielemental enteral feeds for infants with protracted diarrhea, a higher-fat semielemental diet may be the most appropriate way to provide adequate caloric intake.

Diarrhea, Infantile↗

Proximal small intestinal mucosal injury. Maintenance of glucose and glucose polymer absorption, attenuation of disaccharide absorption.

The effect of chronic intragastric infusion of hypertonic mannitol on small intestinal mucosal structure and function was studied in adult rats. Animals were gavage-fed 20% mannitol (1300 mosm) at a dose of 5 ml/100 g body weight daily for seven days. Control animals were gavage-fed tap water on the same schedule. On day 8, the animals were anesthetized, the duodenum cannulated, and a test sugar (glucose, glucose polymer, lactose, sucrose, or maltose) was infused at a dose of 0.5 g/kg body weight in 2.5 ml distilled water over less than 1 min. Portal vein glucose was measured at 30-min intervals from 0 to 120 min. Mannitol treatment resulted in histologic and biochemical alterations (reduced lactase, sucrase, maltase) limited to the proximal small intestine compared to the control group. The absorption of glucose and glucose polymers was similar in mannitol-treated and control animals. In contrast, digestion and absorption of lactose, sucrose, and maltose was significantly diminished in mannitol-treated animals when compared to controls. No changes in permeability to polyethylene glycol 4000 or Na+-coupled glucose transport were observed in mannitol-treated animals compared to controls. These data suggest that when the intestinal mucosa is exposed to hyperosmolar loads that the digestive capacity for disaccharides is suppressed more than its glucose absorptive capacities. Furthermore, glucose oligomers may be more readily digested and absorbed than disaccharides, in this setting, due, in part, to the proximal injury and less pronounced proximal-distal gradient for glucoamylase than other brush-border carbohydrases.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Isolated colonocyte metabolism of glucose, glutamine, n-butyrate, and beta-hydroxybutyrate in malnutrition.

The colonic mucosa may be especially vulnerable during starvation and malnutrition, as luminal nutrients make the greatest contribution to its energy production. To investigate possible metabolic changes in the colonic mucosa during nutrient restriction, we studied substrate utilization by colonocytes isolated from three groups of 6-wk-old rats: control, fasted (72 h), and chronically malnourished animals. Isolated colonocytes were incubated with nonlabeled and 14C-labeled substrates (glucose, glutamine, n-butyrate, or beta-hydroxybutyrate). Substrate oxidation and net increase of intermediary metabolites were reduced in fasted and malnourished animals. The effect of fasting on substrate oxidation was greater than that of chronic malnutrition for all substrates tested except n-butyrate. The total ketone body concentrations and beta-hydroxybutyrate to acetoacetate ratios were higher in the fasted and malnourished groups than in controls. The findings suggest that the colonic mucosa responds to nutrient deprivation by a general reduction of oxidative metabolism that is associated with an altered redox state.

3-Hydroxybutyric Acid↗

Rat pancreatic nuclear thyroid hormone receptor: characterization and postnatal development.

To document the presence of 3,5,3'-triiodothyronine nuclear receptor in the rat pancreas, the solubilized pancreatic nuclear fraction was characterized for its binding to 3,5,3'-L-triiodothyronine. Binding was found to be reversible, saturable, and specific. Scatchard analysis revealed a single class of 3,5,3'-L-triiodothyronine receptors in the pancreata of adult rats. The dissociation constant was 0.29 +/- 0.02 x 10(-9) M, and maximal binding capacity was 242 +/- 10 fmol of T3 bound per milligram of nonhistone protein at 30 degrees C (n = 20). Both parameters are comparable with those of adult rat liver nuclei. The degree of receptor occupancy was 30%-40% of the total sites in the adult rat pancreas. Developmentally, 3,5,3'-L-triiodothyronine binding was not detectable at birth and very low in pups less than 5 days old. It reached a peak at the third to fourth weeks. The degree of receptor occupancy changed with development from a low (19.2% +/- 2.0%) in 5-10-day-old pups to a high (50.5% +/- 3.0%) in 11-20-day-old pups, then returned to a moderate level (36.9% +/- 3.0%). The dissociation constants remained unchanged at various postnatal ages. Our data suggest that the rat pancreas is a target tissue for thyroid hormone and that thyroxine plays a role in pancreatic development.

Aging↗

Response of exocrine pancreas to corticosterone and aldosterone after adrenalectomy.

The long-term effect of adrenalectomy (Adx) on the exocrine pancreas was examined in female adult rats. Pancreatic amylase concentration decrease to 50% of the control level starting 10 days after Adx, whereas the levels of trypsinogen and lipase remained unchanged. Replacement studies beginning 24 h after surgery with corticosterone (B, 1 mg/100 g body wt) or aldosterone (ALDO, 8 micrograms/100 g body wt) alone did not prevent the decline in amylase after Adx. However, when both hormones were administered together, pancreatic amylase concentration was maintained at a level similar to that of the control group. Serum corticosterone levels in the rats receiving B alone or B + ALDO were not different, and were comparable to levels found in normal rats. Both ALDO and B, given for 5 days starting 10 days after Adx, were required to restore amylase concentrations toward control values. When spironolactone (SPIRO, 3 mg/100 g body wt), a specific mineralocorticoid receptor blocker was administered bid together with ALDO + B, it blocked the increase in pancreatic amylase seen in ALDO + B treated rats but did not affect the serum corticosterone levels. These results suggest that mineralocorticoids are also involved in modulating the level of amylase in the rat exocrine pancreas.

Adrenal Glands↗

Quantitation of urinary carnitine esters in a patient with medium-chain acyl-coenzyme A dehydrogenase deficiency: effect of metabolic state and L-carnitine therapy.

Urinary carnitine esters were quantitated in an infant with medium-chain acylcoenzyme A dehydrogenase deficiency by means of a highly sensitive and specific radioisotopic exchange high-pressure liquid chromatography method. During fasting, the excretion of free carnitine and of acetylcarnitine, octanoylcarnitine, and hexanoylcarnitine was increased. The fractional tubular reabsorption of free carnitine was decreased, suggesting a renal leak of free carnitine. In the symptom-free, fed state, only minor amounts of free carnitine and of short-chain acylcarnitine, octanoylcarnitine, and hexanoylcarnitine were present in urine, and carnitine loss occurred in the form of "other" carnitine esters not exceeding that of control subjects. During L-carnitine therapy, the excretion of free carnitine, short-chain acylcarnitine, octanoylcarnitine, and hexanoylcarnitine, and particularly of "other" carnitine esters, was increased, suggesting a possible detoxifying effect of administered carnitine that is not confined to the elimination of octanoic and hexanoic acids. The employed method detects very low urinary concentrations of octanoylcarnitine and hexanoylcarnitine (less than 1 mumol/L) characteristic of medium-chain acyl-coenzyme A dehydrogenase deficiency and may be useful in screening for this disease, which has been associated with sudden infant death.

Acetylcarnitine↗

Biochemical and morphological changes in the digestive tract of rats after prenatal and postnatal malnutrition.

Six-week-old rats subjected to prenatal and postnatal dietary restriction (maternal and weanling intake = 50% that of controls) were studied. Compared with controls, malnourished rats not only had reduced body (78 +/- 12 vs 187 +/- 21 g) and organ weights (small intestine: 4.51 +/- 0.46 vs 9.89 +/- 0.61 g; colon: 0.75 +/- 0.08 vs 1.77 +/- 0.18 g; liver: 2.75 +/- 0.34 vs 9.13 +/- 1.33 g; pancreas: 0.78 +/- 0.14 vs 1.67 +/- 0.49 g) but also decreased body weight-length ratios (6.5 +/- 0.3 vs 10.8 +/- 1.4 g/cm) and serum albumin levels. The small intestinal mucosa was hypotrophic (protein-DNA ratio: 5.02 +/- 1.43 vs 8.82 +/- 0.68, malnourished vs controls, respectively) with reduced mucosal thickness, villus height, and crypt depth. Specific activities of lactase, maltase, and sucrase were diminished (53%, 66%, 54% of control values, respectively). Colonic mucosa was hypoplastic with decreased mucosal thickness and crypt depth. Liver and pancreas were both hypotrophic and hypoplastic. The findings suggest that, in contrast to colonic mucosa, pancreas, and liver, the small intestinal mucosa maintained cell number during prolonged prenatal and postnatal malnutrition.

Animals↗

Phorbol ester potentiates VIP-stimulated amylase release in rat pancreatic acini.

Vasoactive intestinal peptide (VIP) or 12-O-tetradecanoylphorbol-13-acetate (TPA) individually stimulated amylase release in dispersed rat pancreatic acini. Pretreatment of acini with TPA (10(-6) M) for 5 min at 37 degrees C potentiated their subsequent response to stimulation by VIP at a dose range of 10(-8)-10(-6) M in that the treated pancreatic acini released more amylase than could be accounted for by the additive effects of VIP or TPA acting individually. This potentiation effect of TPA was still evident when isobutyl methylxanthine was given together with VIP. Further, the maximal' dose-response curve to VIP shifted 2 log units to the left (3 x 10(-9) versus 3 x 10(-7) M). The TPA preincubation was found also to potentiate VIP-stimulated net increases in intracellular cyclic AMP (cAMP) levels. A close correlation existed between the net releases of amylase and the net increases in intracellular cAMP levels (r = 0.97). This suggested that TPA potentiated the response of rat pancreatic acini to VIP by modulating the cAMP system. The TPA as a potent activator of protein kinase C may act as a modulator of the adenylate cylase-cAMP system in rat pancreatic acini.

Amylases↗

Chronic pancreatitis with diffuse fibrosis in early childhood.

A 2-year old girl is described in which biliary obstruction was the initial presentation of chronic pancreatitis. A pancreatic biopsy done at laparotomy showed extensive fibrosis not explained by her short clinical course. Chronic pancreatitis with fibrosis in childhood is reviewed.

Child, Preschool↗

Serum antibodies to cow's milk proteins in pediatric inflammatory bowel disease: Crohn's disease vs. ulcerative colitis.

Serum antibodies to five cow's milk proteins, alpha-casein, bovine serum albumin (BSA), beta-lactoglobulin A and B (BLG-a, BLG-b) and alpha-lactalbumin (ALA) were investigated in young patients with inflammatory bowel disease, 56 with Crohn's disease (CD), 24 with ulcerative colitis (UC). IgG antibodies against BSA and BLG-a and -b were higher in Crohn's disease patients as compared to those with ulcerative colitis and controls. The IgG anti-BSA were higher in the group of CD patients with higher score of disease activity. Additionally, IgA antibodies to alpha-casein were higher in CD and UC compared to control. These findings may be due to increased uptake of dietary antigens or enhanced immunological response occurring in CD patients.

Adolescent↗

Serum antibodies to cow's milk proteins in pediatric inflammatory bowel disease. Crohn's disease versus ulcerative colitis.

Serum antibodies to five cow's milk proteins (alpha-casein, bovine serum albumin, beta-lactoglobulin A and B, and alpha-lactalbumin) were investigated in young patients with inflammatory bowel disease (56 Crohn's disease, 24 ulcerative colitis). IgG antibodies against bovine serum albumin, beta-lactoglobulin A and beta-lactoglobulin B were higher in Crohn's disease patients than in those with ulcerative colitis or the controls. IgG anti-bovine serum albumin antibodies were higher in those Crohn's disease patients who had higher scores of disease activity. Finally, IgA antibodies to alpha-casein were higher in patients with Crohn's disease and ulcerative colitis when compared to controls. These findings may be due to increased uptake of dietary antigens or enhanced immunological response occurring in Crohn's disease patients.

Adolescent↗

Concanavalin A promotes adherence of Salmonella typhimurium to small intestinal mucosa of rats.

A number of dietary lectins have been shown to resist proteolytic digestion. These lectins interact with the small intestinal mucosa causing structural and functional changes. Concomitant to these changes, bacterial overgrowth was reported and a possible interaction between lectins and bacteria in the small intestine was postulated. The aim of this study was to investigate the effect of various lectins on adherence of Salmonella typhimurium to both isolated small intestinal enterocytes and ligated intestinal loops. Isolated intestinal cells or ligated intestinal loops were incubated with [3H] adenine-S. typhimurium in the presence or absence of concanavalin A, phytohemagglutinin, peanut agglutinin, and wheat germ agglutinin. Only concanavalin A promoted the adherence of various strains of nonfimbriated S. typhimurium to isolated viable intestinal cells. Other lectins showed no effect on the adherence. In situ studies showed that bacterial binding was increased in concanavalin A-treated intestinal loops, supporting the significance of the experiments in vitro. These data suggest that lectins may act by promoting bacterial adherence to the small intestine, thereby facilitating colonization and infection, and leading to bacterial overgrowth.

Animals↗

Immature stimulus-secretion coupling in the developing exocrine pancreas and ontogenic changes of protein kinase C.

Previous observations have shown unresponsiveness of pancreatic acini to cholecystokinin C-terminal octapeptide (CCK-8) and cholinergic agents in newborn rats. In this study, the possibility that a lack of protein kinase C may be one factor limiting the responsiveness of the acini was examined. In the term fetus and in newborns cytosolic protein kinase C activity was low. Shortly after birth, the activity increased rapidly and by 2 days of age reached adult levels which were 5-fold higher than that in the newborn. No differences in subcellular distribution of protein kinase C activity between the particulate and the cytosol fractions were found at any age studied. Developmental profiles of phorbol dibutyrate binding, an alternative method for measuring protein kinase C, were similar to those of protein kinase C activity measurements. Using stimulation of amylase secretion as an index of responsiveness, dispersed pancreatic acini of newborn rats were found to be unresponsive to TPA (a potent activator of protein kinase C) and CCK-8, but were responsive to dibutyryl cAMP and calcium ionophore A23187 (agents not dependent on protein kinase C activity). These results suggest that the low levels of pancreatic protein kinase C in newborn rats are at least in part responsible for the unresponsiveness of pancreatic acini to 12-O-tetradecanoylphorbol 13-acetate and CCK-8.

Amylases↗

Effects of graded alpha-glucosidase inhibition on sugar absorption in vivo.

The effect of inhibition of disaccharidases on the degree of absorption of glucose, lactose, and sucrose was examined utilizing an in vivo model in the rat. Acarbose, a competitive alpha-glucosidase inhibitor was utilized to selectively inhibit small intestinal mucosal enzymes. Adult rats (250-350 g body weight) were the subjects of intraduodenal bolus infusion experiments with either sugar alone or sugar plus acarbose. All sugars were infused at a dose of 0.5 g/kg body weight. Portal venous blood glucose was determined at 30-min intervals from 0 to 150 min. Glucose (monosaccharide) and lactose (beta-galactoside) absorption were not altered by the presence of acarbose. In contrast, sucrose (alpha-glucosidase) absorption was significantly diminished in the presence of acarbose. Sucrose absorption in the presence of increasing acarbose doses (0.7-5.6 mg/kg body weight) was depressed in a dose-dependent fashion. Linear regression analysis revealed a high degree of correlation between residual sucrase activity and area under blood glucose curve (r = 0.9837). Similar degrees of correlation were found between acarbose dose and area under blood glucose curve (r = -0.9322), and between residual sucrase activity and acarbose dose (r = -0.9695). These data confirm that acarbose is a selective alpha-glucosidase inhibitor that does not affect monosaccharidase transport. In the presence of acarbose, alpha-glucosidase absorption is diminished in a dose-dependent fashion. Postprandial glucose rise following an alpha-glucosidase meal seems to be determined, in the presence of graded acarbose inhibition, by residual mucosal alpha-glucosidase activity.

Acarbose↗

Oral feeding of isolated lectins from red kidney bean stimulates rat small intestinal mucosal DNA synthesis and crypt cell division.

A lectin preparation containing enterokinase inhibitor purified or partially purified from red kidney bean (RKB) when fed to weanling rats was shown to cause small intestinal hyperplasia. To see if this hyperplastic effect on the rat small intestine was due to the mitogenic properties of the isolated lectin, male weanling rats were fed a chow containing 0.1% of the isolated lectin for six days. Age-matched control rats were fed regular chow. Both control and lectin-fed rats were sacrificed at one, two, three, four, and six days after the start of lectin feeding. The proximal small intestinal mucosa of rats fed lectin showed gradual increases in protein and DNA contents throughout the experimental period. Morphological studies showed marked increases in crypt depth from days 1 through 6 in these rats with essentially no change in mucosal thickness or villous height. DNA synthetic activity peaked at day 2, but was higher than control throughout the experimental period. Labeling index was 0.36 +/- 0.03 in duodenum of controls as compared to 0.45 +/- 0.02 in duodenum of weanling rats fed lectin for two days. These results demonstrate that RKB lectin stimulates overall DNA synthetic activity and increases crypt cell proliferation on the small intestine of weanling rats. The observed mucosal hyperplasia is probably due to increases in crypt cell population as shown by the increase in crypt depth.

Animals↗