Role of tyrosine kinase, ODC, and p34cdc2 kinase and cyclin B-associated cdc2 in jejunal enterocyte proliferation, maturation, and exfoliation in diabetic and DFMO-treated rats.

Background: Several signal transduction pathways involved in rapidly proliferating cells of the intestine are currently not well understood. In the jejunum, crypt enterocytes are constantly replicating, lower villi are maturing, and upper villi are constantly shed. Type I diabetes is associated with jejunal mucosal hyperplasia, and administration of diflouromethylornithine (DFMO), an irreversible inhibitor of ornithine decarboxylase (ODC), causes hypoplasia.

Effects of diabetes and difluoromethylornithine treatment on hyperplasia, activity of MAP-kinase, and activity and association with cyclin B of p34cdc2 kinase in rat jejunal mucosa.

Background: The different signal transduction pathways of rapidly proliferating cells of the intestine are not clearly understood. We report here a possible signaling pathway that involves regulation of activity of two closely related kinases, MAP-K (mitogen-activated protein kinase) and p34cdc2 kinase, during hyperplasia of diabetic jejunal mucosa. Our aim was to investigate the activity and phosphorylation of MAP-K and activity and association of p34cdc2 kinase with cyclin B during diabetes-induced jejunal mucosal hyperplasia in vivo.

Relation of ornithine decarboxylase and tyrosine kinase activity in the jejunal mucosa in vivo.

Our aim was to study the relationship between jejunal mucosal activity of ornithine decarboxylase and tyrosine kinase during proliferation in adolescent rats in vivo. Their relationship in the proliferating intestinal mucosa under in vivo conditions has not been reported before. From the results of in vitro studies, it was speculated that tyrosine kinase activity modulated ornithine decarboxylase activity during colonic mucosal proliferation (Majumdar AP.

Diagnosis of gastroesophageal reflux in pediatrics.

Gastroesophageal reflux (GER) may be normal, functional, or pathogenic. Normal GER is of short duration and seen in all individuals. Functional GER, or effortless regurgitation, is common during infancy, causing no ill effects.

Intestinal mucosal ornithine decarboxylase and brush border membrane vesicle Na(+)-H+ exchange activities in diabetic rats.

To determine the possibility that intestinal mucosal ornithine decarboxylase activity can modulate mucosal brush border membrane Na(+)-H+ exchange activity, we studied the relationship between jejunal mucosal ornithine decarboxylase activity and mucosal brush border membrane Na(+)-H+ exchange activity in adolescent streptozotocin-diabetic and normal control rats. Diabetes was associated with enhanced intestinal mucosal ornithine decarboxylase and Na(+)-H+ exchange activities. Groups of diabetic and control rats were given difluoromethylornithine in drinking water to suppress intestinal mucosal ornithine decarboxylase activity.

Polyamines and intestinal epithelial hyperplasia in streptozotocin-diabetic rats.

We measured specific activity of ornithine decarboxylase (ODC) and contents of putrescine and of the polyamines (spermidine and spermine) in isolated villus and crypt enterocytes from the jejunum of adolescent streptozotocin-diabetic and weight-matched control rats and diabetic and control rats treated with difluoromethyl ornithine (DFMO) 10 days after induction of diabetes. Consistent with previous observations by others of elevated ODC activity and contents of putrescine and of the polyamines in the intestinal epithelium undergoing hyperplasia, our studies showed elevated ODC activity and contents of putrescine and spermidine, but not of spermine, in the hyperplastic intestinal epithelium of diabetic rats. As in previous studies, suppression of ODC activity by DFMO prevented not only the jejunal epithelial hyperplasia in the diabetic rats, but also retarded jejunal epithelial growth in the control rats.

Stooling problems in patients with myelomeningocele.

In children with myelomeningocele fecal and urinary incontinence lowers self-esteem and decreases social interaction. The defects in the lumbosacral spine disturb the sensory and motor nerves supplying the skin and muscles of the perianal region, including the puborectalis muscle, and the external anal sphincter. The sensations in the region, as well as the motor functions of the striated muscles suffer, compromising the dynamics of continence and the normal process of stooling and leading to incontinence and constipation.

Intestinal absorption of aspartame decomposition products in adult rats.

The dipeptide sweetener aspartame (N-L-alpha-aspartyl-L-phenylalanine, 1-methyl ester; alpha-APM) is relatively stable in dry powder form. However, when exposed to elevated temperature, extremes of pH and/or moisture, alpha-APM is converted into a variety of products. In aqueous solution alpha-APM decomposes to yield methanol, two isomeric forms of L-aspartyl-L-phenylalanine (Asp-Phe) [alpha-Asp-Phe and beta-Asp-Phe], and APM's diketopiperazine cyclo-Asp-Phe.

Solitary ulcer syndrome of the rectum in children.

We present two children with solitary ulcer syndrome of the rectum (SUSR): a 7-year-old and an 11-year-old. Although well recognized in the adult literature, the pediatric experience with this condition is limited. We review the clinicopathologic features of SUSR with emphasis on the pediatric experience.

Pseudo-Zollinger--Ellison syndrome in a child presenting with anemia.

Pseudo-Zollinger--Ellison syndrome appears to very rarely afflict young children. Hypergastrinemia, regardless of the etiology, presents with signs and symptoms of nonhealing or multiple gastric or duodenal ulcers, or both. We present a 7-yr-old boy with fasting hypergastrinemia (serum gastrin 200-500 pg/ml) who had mild to moderate iron deficiency anemia, but was asymptomatic.

Chronic intestinal pseudoobstruction in young children.

We studied 8 young children (4 boys and 4 girls) with chronic intestinal pseudoobstruction. Intestinal pseudoobstruction, recurrent urinary tract infections, and dysuria occurred between the ages of a few weeks to 5 yr old. All had marked dilatation of the entire gastrointestinal tract distal to the esophagus, and megacystis.

Effect of acidosis and hypoxia on intestinal blood flow of sheep fetus.

In sheep fetuses 110-130 days of age acidosis (blood pH 6.95; produced by infusion with 1.1 M lactic acid) significantly lowered blood flow (ml/min/100g) to the full thickness wall of the jejunum from 135 +/- 11 to 93 +/- 14 and in the full thickness wall of the ileum from 122 +/- 13 to 95 +/- 11.

Comparison of in vitro jejunal uptake of L-valine and L-lysine in the rat during maturation.

The maturational characteristics and patterns of absorption of the neutral amino acid L-valine were compared with those of the basic amino acid L-lysine using in vitro preparations of everted sacs obtained from the jejunum of suckling (2 weeks old), weanling (3 weeks old), and adolescent (6 weeks old) rats. Absorption rates determined as net transport into sac fluid and mucosal uptake (mumol/h/g protein or weight of mucosal scrapings) for both valine and lysine were greater in the suckling than in the weanling or adolescent rats. This appeared to be true for both the carrier-mediated and the diffusive processes for absorption, determined from the relationship between the observed absorption rates and the corresponding mucosal incubation medium amino acid concentrations.

Effect of nutritional method on adaptation of the intestinal remnant after massive bowel resection.

Adaptation of the intestinal remnant with hypertrophy/hyperplasia and increased absorption occurs, ultimately, after massive bowel resection. During the early postresection period, the rate of the adaptational process may be influenced by the method of nutritional support. Nutrients given by mouth may support a strong stimulus for hypertrophy but may be incompletely absorbed from the short intestinal remnant.

Intestinal calcium absorption is enhanced by D-glucose in diabetic and control rats.

The effect of glucose on intestinal absorption of calcium was studied in the jejunum and ileum of control, diabetic (streptozotocin-induced), and insulin-treated diabetic rats. Intestinal absorption was determined in vivo using an in situ one-pass perfusion technique. In the jejunum of control and diabetic rats, net absorption and unidirectional lumen to mucosa flux of calcium and net absorption of water were significantly greater during perfusion of an isotonic NaCl solution, containing 15 mmol/L of glucose, than during perfusion of the same solution containing 15 mmol/L of mannitol instead of glucose.

Intestinal maturation: effect of growth retardation on L-valine absorption.

The absorption of L-valine was studied in segments of the jejunum and ileum using a one pass in situ perfusion technique in 1-, 2-, 3-, and 4-wk-old healthy control and in growth-retarded rats (suckled with mothers fed a protein-deficient diet and fed the same diet after weaning). In the jejunum of control rats, rate of absorption of L-valine declined from about 270 to 80 mumol/h per g mucosal weight, between 2 and 4 wk of life. At each age period, in both segments, rates of absorption of L-valine based on weight of the segments were significantly greater in the growth-retarded than in the control rats.

Effect of treatment on rectal and sigmoid motility in chronically constipated children.

Using three pressure transducers, motility of the lower and upper rectum and sigmoid was recorded in 18 healthy and 18 chronically constipated children. The 36 children had a wide range of values for frequency of contractions, duration, amplitude, percent of activity, and surface area under the contraction curves. The mean values for percent of activity and surface area were significantly lower in the constipated than in the control children in all three recording areas (P less than .

Secretory diarrhea in ulcerative colitis.

Severe secretory diarrhea developed in a 15-year-old girl with ulcerative colitis restricted to the distal 30 cm of the colon. No known hormonal or pathologic cause for the secretory diarrhea was discovered. Since the diarrhea subsided after colectomy, it appeared to be secondary to a factor(s) in the inflamed bowel.

Abnormal and sphincter response in chronically constipated children.

Using a strain gauge, we measured anal sphincter function in 116 chronically constipated and 18 healthy children. Eighteen constipated children were re-evaluated two months later (receiving laxative), and 15 were again studied seven to 12 months later. The anal resting tone varied along the length of the anal canal and was highest at 1 to 1.

Intestinal maturation: in vivo loss of calcium in suckling and adult rats.

Intestinal permeability to Ca is greater in infant than in older rats, predisposing the infant rat to hypocalcemia. The present studies compared in suckling and adult rats the amount of Ca lost into the intestinal lumen in relation to plasma Ca during an acute 2-h in vivo recirculation perfusion of the jejunum and ileum with an isotonic NaCl solution either free of or containing CaCl2. Rats had been injected with radioactive 45CaCl2 24 h prior to the perfusion.

Intestinal disaccharidases in malnourished infant rats.

In infants suffering from protein-calorie malnutrition, the decreased intestinal mucosal lactase specific activity could be due either to the protein-calorie malnutrition or to the commonly associated enteritis (viral or bacterial) and intestinal parasites. We studied intestinal mucosal disaccharidase (lactase, sucrase, and maltase) specific activity in suckling (1 and 2 wk old), weanling (3 wk old), and postweaning (4 and 6 wk old) control and growth-retarded (malnourished) rats. Growth retardation was induced by feeding mother rats and postweaning rats a diet deficient in protein.