Regulation of intestinal peptidases by nutrients in human fetuses and children

Nutrient interactions during intestinal digestion has been established in animals. The present study investigated the effect of different nutrients on intestinal dipeptidase, tripeptidase, carboxypeptidase (EC 3.4.12.-) and aminopeptidase N (ApN) (EC 3.4.11.2) activities in human fetuses and children. The effect of nutrients on isolated porcine kidney ApN was also studied. Sucrose, lactose and tributyrin had no effect on di-, tri-, and carboxypeptidase activities of mucosal homogenates, but tributyrin significantly (20-50%) inhibited both fetal and postnatal ApN activity in the small intestine and colon. The pH-independent inhibition of ApN is specific for tributyrin and to the product of its hydrolysis, butyric acid. Glycerol, triolein, and natural oils did not affect ApN activity. The inhibition of ApN by tributyrin was dose and time dependent and occurred in enterocyte brush border membranes as well as in the purified enzyme from porcine kidney. The kinetics of the purified ApN showed that the tributyrin effect is primarily competitive and associated mainly with an increase in K(m). These observations demonstrate the possibility of intestinal and kidney ApN regulation by lipids and products of their hydrolysis. We speculate that nutrient interactions arose quite early in the evolution and represent a mechanism for the regulation of food digestion.

Quality-of-life assessment after ileoanal pull-through for ulcerative colitis and familial adenomatous polyposis

BACKGROUND/PURPOSE

The ileoanal pull-through procedure (IAP) is gaining increasing favor and use in the surgical treatment of children with ulcerative colitis (UC) and familial adenomatous polyposis (FP). Although physiological studies have been performed to assess the outcome of these children, no long-term quality-of-life assessment after the procedure has been performed.

METHODS

Forty-three patients were identified who had an IAP at our institution in the last 10 years and were at least 6 months postsurgery. Thirty-four were contacted, and 32 agreed to participate in the survey, which was approved by the Human Studies Committee. Participants completed the standardized Medical Outcome Study Short Form-36 (SF-36), which has well-established normative values. Several supplemental questions were prepared in a similar format dealing with issues specific to the ileoanal pull-through procedure.

RESULTS

Of the 32 participants, 19 (59%) were girls and 26 (81%) had ulcerative colitis. Mean age at the time of survey was 18.1 years with 12 less than 18 years and 20 > or =18 years. Data from the latter group could be compared with national normative values for this age. The study group was not statistically different from age-appropriate US population normal values on all assessable scales of physical and mental health in the SF-36 survey including physical functioning, role limitations-physical, bodily pain, general health, vitality, social functioning, role limitations-emotional, and mental health (all P>.05 or mean difference SD units <0.8). The supplemental questionaire demonstrated little adverse effect of the surgery. There was limited consumption of medications to control bowel frequency and little restriction of activity because of the frequency of bowel movements or fear of incontinence. The surgical scar was the sole negative factor of significance.

CONCLUSIONS

The ileoanal pull-through procedure is an excellent surgical option for children with ulcerative colitis or familial adenomatous polyposis, and it produced minimal, if any, adverse effects on their long-term quality of life.

A position paper of the North American Society for Pediatric Gastroenterology and Nutrition. Pediatric gastroenterology Workforce Survey and future supply and demand

BACKGROUND

The North American Society for Pediatric Gastroenterology and Nutrition (NASPGN) performed a Workforce Survey to determine the current number and distribution of pediatric gastroenterologists in the United States and Canada and to estimate the supply and demand in the future in the United States.

METHODS

The response rate was more than 90%. There were 624 pediatric gastroenterologists in the United States, and 48 in Canada.

RESULTS

There were 2.4 pediatric gastroenterologists per million population in the United States, ranging from 3.1 per million in the Northeast to 1.9 per million in the West, and 1.6 per million in Canada. In the United States, fewer than 5 pediatric gastroenterologists retire each year, but more than 40 fellows per year complete training. In the United States, 30% of pediatric gastroenterologists believe there is already an excess supply; only 12% believe there is a shortage (p < 0.001).

CONCLUSIONS

If the number of fellows who complete training each year remains unchanged, in 10 years there will be more than 950 pediatric gastroenterologists in the United States (3.3 per million population). At the same time, if the demand for pediatric gastroenterologists remains 2.4 per million population, there will be a demand for only 675. If these assumptions are correct, it is necessary to reduce the number of fellows to be trained. Although it is difficult to predict future workforce needs reliably, we recommend that the number of fellowship positions in training programs in the United States be reduced by 50% to 75%. Changes in health care in the coming years will be challenging, and effective planning is necessary for pediatric gastroenterologists to achieve their clinical, research, and educational missions.

The TCR-delta repertoire in human intestine undergoes characteristic changes during fetal to adult development

The TCR-delta repertoire in adult human intestine is oligoclonal and unique in each individual. In the present study, changes in the junctional regions of TCR-delta transcripts in human intestine that occur during development from fetal to adult life were used to characterize fundamental changes in the TCR-delta repertoire in the human intestinal tract during ontogeny. At mid-gestation, the fetal repertoire was polyclonal, but limited, in its junctional diversity by the relative lack of N region nucleotide additions and by the frequent formation of coding region joins at regions of short sequence homology. In addition, identical TCRDV2 transcripts that resemble canonical TCR-delta sequences in mice were present in the intestine of different fetuses. In the early period after birth, the intestinal TCR-delta repertoire was polyclonal, and more diverse than the fetal repertoire, with junctional regions that contained extensive N nucleotide additions and frequently were as complex as those of adults. The intestinal TCR-delta repertoire showed increasing restriction with age and, by 14 to 17 yr, the repertoire was oligoclonal and resembled the repertoire of individuals in the sixth to seventh decade. Moreover, the adult TCR-delta repertoire was almost identical at multiple sites throughout the intestine, suggesting a model in which gammadelta T cell clones, selected by ligands in the intestinal tract, undergo expansion and recirculation before lodging throughout the small intestine or colon.

The TCR-delta repertoire in human intestine undergoes characteristic changes during fetal to adult development

The TCR-delta repertoire in adult human intestine is oligoclonal and unique in each individual. In the present study, changes in the junctional regions of TCR-delta transcripts in human intestine that occur during development from fetal to adult life were used to characterize fundamental changes in the TCR-delta repertoire in the human intestinal tract during ontogeny. At mid-gestation, the fetal repertoire was polyclonal, but limited, in its junctional diversity by the relative lack of N region nucleotide additions and by the frequent formation of coding region joins at regions of short sequence homology. In addition, identical TCRDV2 transcripts that resemble canonical TCR-delta sequences in mice were present in the intestine of different fetuses. In the early period after birth, the intestinal TCR-delta repertoire was polyclonal, and more diverse than the fetal repertoire, with junctional regions that contained extensive N nucleotide additions and frequently were as complex as those of adults. The intestinal TCR-delta repertoire showed increasing restriction with age and, by 14 to 17 yr, the repertoire was oligoclonal and resembled the repertoire of individuals in the sixth to seventh decade. Moreover, the adult TCR-delta repertoire was almost identical at multiple sites throughout the intestine, suggesting a model in which gammadelta T cell clones, selected by ligands in the intestinal tract, undergo expansion and recirculation before lodging throughout the small intestine or colon.

Intestinal and hepatobiliary diseases in HIV-infected children

Children with HIV disease and gastrointestinal disease should be evaluated for enteric pathogens. Bacterial, protozoal, and viral agents can cause chronic diarrhea, abdominal pain, gastrointestinal bleeding, and contribute to growth retardation. This article presents an approach to the evaluation of the HIV-infected child with gastrointestinal symptoms. Therapeutic and nutritional interventions are discussed with emphasis on the multidisciplinary approach required to initiate successful management.

Anti-neutrophil cytoplasmic antibodies in children with ulcerative colitis

Tests that positively identify individuals with ulcerative colitis, distinguishing them from patients with Crohn disease or other causes of colitis, have not been reliable. Genetic predisposition to inflammatory bowel diseases and genetic influence on immune regulation resulted in the clinical evaluation of potential serologic markers. In adults the presence of anti-neutrophil cytoplasmic antibody (ANCA) in serum identifies patients with ulcerative colitis. In this study we demonstrated that high levels of ANCA are present in 83% of children and adolescents with ulcerative colitis. Furthermore, the majority of patients with ulcerative colitis had a perinuclear pattern of these antibodies by indirect immunofluorescence. The combination of a positive ANCA and perinuclear indirect immunofluorescence pattern was 97% specific for ulcerative colitis. We conclude that determination of ANCA is a sensitive and specific clinical test for identification of children and adolescents with ulcerative colitis.

Anti-neutrophil cytoplasmic antibodies in children with ulcerative colitis

Tests that positively identify individuals with ulcerative colitis, distinguishing them from patients with Crohn disease or other causes of colitis, have not been reliable. Genetic predisposition to inflammatory bowel diseases and genetic influence on immune regulation resulted in the clinical evaluation of potential serologic markers. In adults the presence of anti-neutrophil cytoplasmic antibody (ANCA) in serum identifies patients with ulcerative colitis. In this study we demonstrated that high levels of ANCA are present in 83% of children and adolescents with ulcerative colitis. Furthermore, the majority of patients with ulcerative colitis had a perinuclear pattern of these antibodies by indirect immunofluorescence. The combination of a positive ANCA and perinuclear indirect immunofluorescence pattern was 97% specific for ulcerative colitis. We conclude that determination of ANCA is a sensitive and specific clinical test for identification of children and adolescents with ulcerative colitis.

Quantitative analysis of mononuclear cells expressing human immunodeficiency virus type 1 RNA in esophageal mucosa

The mucosa of the gastrointestinal tract is presumably an important reservoir for human immunodeficiency virus type 1 (HIV-1), but the level of virus-expressing cells within the mucosa of infected patients is not known. To study this issue, we identified HIV-1 mRNA-expressing (positive) mononuclear cells by in situ hybridization in specimens of esophageal mucosa from eight patients with acquired immune deficiency syndrome (AIDS) and esophageal infections. Such cells were not found in four patients with AIDS and no esophageal disease. Immunocytochemical staining revealed that the mononuclear cells expressing HIV-1 mRNA were lamina propria macrophages. The prevalence of positive cells was measured by triplicate determinations in each of three experiments using an inverse sampling technique. No significant differences in prevalence were found among patients or among experiments. The overall prevalence of HIV-1 mRNA-expressing cells in the esophageal lamina propria was 0.059 +/- 0.01%. This prevalence of cells expressing HIV-1 mRNA in the mucosa of patients with mucosal infections may reflect the local abundance of stimuli such as bacterial endotoxin and certain cytokines capable of inducing viral transcription.

Anorectal function in children after ileoanal pull-through

Mucosal proctectomy and ileoanal pull-through is increasingly used in children requiring total colectomy for ulcerative colitis or familial polyposis. Excellent continence can be achieved with this procedure, and it avoids proctocolectomy and permanent ileostomy. We have evaluated prospectively anorectal function in nine consecutively treated children who underwent ileoanal pull-through. Patients were 8 to 17.5 years of age (median, 11.3 years) at the time of surgery; seven had ulcerative colitis, and two had familial polyposis. Anorectal evaluation was performed before colectomy and ileoanal pull-through, following ileoanal pullthrough, after rectal training, and then at yearly intervals. A biofeedback "rectal training" program was instituted 6 weeks after ileoanal pull-through and a contrast study documenting integrity of the pouch. The program consisted of an initial biofeedback session with the motility unit, followed by daily instillations, through a catheter, of progressively larger volumes of water (from 1 to 6 oz, increasing 1 oz per week) into the ileal pouch. Patients were instructed to retain the water and participate in normal activities after the instillation. This protocol acclimated the patient to sensing distension of the pouch and using the sphincters. The follow-up period ranges from 1 to 4.5 years (median, 2.2 years). All patients are continent by day and night. One patient has nocturnal incontinence with episodes of pouchitis. Stool frequency is three to eight movements per day (median, four), with none at night. Preoperative resting rectal sphincter pressures averaged 74.3 +/- 23.1 mm Hg (mean +/- standard deviation), and a maximum squeeze pressure was 93.9 +/- 25.3 mm Hg.(ABSTRACT TRUNCATED AT 250 WORDS)

Olsalazine versus sulfasalazine in mild to moderate childhood ulcerative colitis: results of the Pediatric Gastroenterology Collaborative Research Group Clinical Trial

The safety and efficacy of olsalazine sodium was compared to sulfasalazine over 3 months in a multicenter, randomized, double-blind study of 56 children with mild to moderate ulcerative colitis. Twenty-eight children received 30 mg/kg/day of olsalazine (maximum, 2 g/day) and 28 received 60 mg/kg/day of sulfasalazine (maximum, 4 g/day). Side effects were frequent in both groups. Eleven of 28 patients (39%) on olsalazine reported headache, nausea, vomiting, rash, pruritus, increased diarrhea, and/or fever. Thirteen of 28 on sulfasalazine (46%) reported similar side effects and/or neutropenia, and four patients had the drug stopped because of an adverse reaction. After 3 months, 11 of 28 (39%) on olsalazine were asymptomatic or clinically improved, compared to 22 of 28 (79%) on sulfasalazine (p = 0.006). In addition, 10 of 28 patients on olsalazine versus one on sulfasalazine required prednisone because of lack of response or worsening of colitis (p = 0.005). The dose of olsalazine used in this clinical trial was thought to be equivalent to a standard dose of sulfasalazine, but fewer patients on olsalazine improved and a greater number had progression of symptoms when compared to sulfasalazine. Although side effects were slightly less frequent for olsalazine, the number of patients was too small to detect a clinically significant difference.

Growth and body composition in children infected with the human immunodeficiency virus-1

Anthropometric data were collected on 89 children born to human immunodeficiency virus (HIV)-infected women (37 who seroreverted and 52 who were HIV-infected). The main outcomes included birth weight, gestational age, weight, height, arm muscle circumference (AMC), and triceps skinfold thickness (TSF). Gestational age and birth weight were not different between the two groups. The earliest anthropometric evaluation on seroreverted children (age 19 mo) when compared with HIV-infected children (age 21 mo) revealed that weight and weight-for-height percentiles were significantly different (51% vs 33% and 66% vs 48%, respectively). Height and TSF percentiles were not different, although AMC percentiles were lower in infected children (64% vs 43%). In follow-up evaluations, the weight differences between infected and control children did not change. We conclude that HIV does not affect birth weight, but postnatal events result in altered weight gain in HIV-infected children. Lean body mass is lower than in an HIV-negative comparison group at early stages of HIV infection.

Glycogen storage disease type III (glycogen debranching enzyme deficiency): correlation of biochemical defects with myopathy and cardiomyopathy

OBJECTIVE

To determine whether a specific subtype of glycogen storage disease type III is associated with myopathy and cardiomyopathy.

DESIGN

Case series.

SETTING

Three referral medical centers.

PATIENTS

All patients with glycogen storage disease type III who were followed in 1990 and for whom both immunoblot analysis and clinical data were available.

MAIN OUTCOME MEASURES

Evaluation for myopathy and cardiomyopathy included determinations of serum creatine kinase activity; muscle strength testing; ischemic exercise testing; nerve conduction studies; and electromyographic, electrocardiographic, and echocardiographic studies.

RESULTS

Three patients with deficient debranching enzyme activity and deficient immunoreactive material in liver but normal debranching enzyme activity in muscle (glycogen storage disease IIIb) had no clinical evidence of myopathy or cardiomyopathy. Serum creatine kinase activity, muscle strength, ischemic exercise testing, electrocardiograms, and echocardiograms were normal in these patients. These studies and electromyograms were abnormal in seven patients with total debranching enzyme deficiency and an absence of immunoreactive material in both liver and muscle (glycogen storage disease IIIa) and in three patients who had debranching enzyme transferase deficiency but normal glucosidase activity in both liver and muscle (glycogen storage disease IIId). All 10 of these patients had progressive myopathy, and 6 had progressive cardiomyopathy.

CONCLUSION

Clinical features of glycogen storage disease type III correlate with the particular biochemical defect seen with the disorder. Assessments of debranching enzyme or debranching enzyme transferase activity in muscle can be used to predict whether patients with glycogen storage disease type III will develop myopathy and cardiomyopathy.

Efficacy of domperidone in infants and children with gastroesophageal reflux

This study sought to define the therapeutic efficacy of domperidone in infants and children with gastroesophageal reflux. A double-blind, placebo-controlled trial was performed in seventeen children (ages 5 months to 11.3 years) with moderate to severe gastroesophageal reflux who had not responded to standard nonpharmacological therapy. Subjective and objective measures (weight gain, esophageal pH probe study, radionuclide gastric emptying scan) of gastroesophageal reflux were evaluated. Therapy with domperidone for 4 weeks was effective only in reducing the total number of reflux episodes in the two-hour postprandial period (p less than 0.01); however, it did not result in symptomatic improvement or significant improvement in other measures of gastroesophageal reflux or gastric emptying. After therapy for 8 weeks symptomatic improvement was reported in some patients who had denied improvement after 4 weeks of therapy, suggesting that more than 4 weeks of therapy may be required for some patients to obtain a clinical response. Mild self-limited diarrhea was reported by six patients (four domperidone, two placebo). We conclude that domperidone is tolerated by most infants and children with gastroesophageal reflux; however, 4 weeks of therapy was only minimally effective in producing objective improvement of gastroesophageal reflux and did not result in symptomatic improvement. Further studies of longer duration are needed to resolve the question raised by this study: that domperidone may be beneficial for patients with gastroesophageal reflux when given for more than four weeks.

Use of an animal model for the study of the role of human immunodeficiency virus 1 in the human intestine

The gastrointestinal manifestations of human immunodeficiency virus (HIV)-1 disease have centered on identifiable causes of intestinal dysfunction such as parasitic and bacterial pathogens. The lamina propria of the intestine contains cell that harbor HIV-1, but the significance of this observation remains unknown. Because limited animal models are available to evaluate the gastrointestinal effects of this infection, a system that uses human fetal intestine transplanted subcutaneously onto the back of an immunodeficient mouse was developed. After 8 weeks, fetal tissues mature into an adult-appearing tissue with a lumen. Cell-free HIV-1 was inoculated into the explants, an evidence for infection was evaluated by histological evaluation, in situ hybridization, and polymerase chain reaction. No evidence for HIV-1 incorporation into epithelial cells could be found. It was concluded that this model provides a system in which intestinal HIV-1 interaction can be evaluated. In this model, cell-free HIV-1 does not appear to infect the epithelial cell.

Pancreatitis in pediatric human immunodeficiency virus infection

Because pancreatitis has been reported frequently in adults with human immunodeficiency virus infection, we sought to determine the incidence of pancreatitis in children with acquired immunodeficiency syndrome by reviewing all records of children with AIDS, their serum amylase and lipase levels, and the factors associated with pancreatitis through a case-control analysis. During a 6-year period pancreatitis developed in 9 (17%) of 53 pediatric patients with AIDS. Six children had vertical transmission of infection and three patients had acquired HIV infection through contaminated blood products. Pancreatitis developed at a median age of 5.2 years (range 1.2 to 20 years). All patients had vomiting and abdominal pain. When the patients were first seen, lipase values were elevated more than amylase values (p = 0.028). Amylase and lipase levels declined at comparable rates. In the case-control analysis, pentamidine isethionate was significantly associated with pancreatitis (p = 0.02); the risk was greater in patients who received pentamidine isethionate and had absolute CD4 T-lymphocyte counts less than 100 cells/mm3 (p = 0.001). Infections associated with the onset of pancreatitis included cytomegalovirus (4), Cryptosporidium (1), Pneumocystis carinii pneumonia (3), and Mycobacterium avium intracellulare (1). Coinfection with cytomegalovirus was associated with a protracted course in four children. Ultrasonographic examination demonstrated biliary ductal dilatation 6 months after the onset of pancreatitis in one child. Seven children have died at a mean of 8 months after the initial onset of pancreatitis; the one living child has survived 5 months from the onset of pancreatitis. We conclude that pancreatitis is common in pediatric patients with AIDS and may be related to pentamidine isethionate exposure, especially when absolute CD4 T-lymphocyte counts are less than 100 cells/mm3. Serum amylase levels do not always accurately predict the onset of pancreatitis; serum lipase levels should be measured in children with symptoms. The onset of pancreatitis in an HIV-infected child is a poor prognostic indicator.

Carnitine deficiency: a possible cause of gastrointestinal dysmotility

An infant with delayed development and peripheral myopathy, nourished on a soy-based liquid diet deficient in carnitine, had gastrointestinal dysmotility manifested by postprandial vomiting, oral drooling, delayed gastric emptying and infrequent bowel movements. Oesophageal manometry showed a reduced lower oesophageal sphincter pressure for age with abnormal distal motility. Serum carnitine concentration was 9.9 mumol l-1. After dietary supplementation of carnitine the gastrointestinal symptoms resolved, oesophageal manometry returned to normal, and serum carnitine increased to 37.2 mumol l-1. Dietary carnitine deficiency in infancy may be a cause of smooth muscle dysmotility of the gastrointestinal tract.

Glycogen debranching enzyme deficiency: long-term study of serum enzyme activities and clinical features

In glycogen storage disease type III (glycogen debranching enzyme (DE) deficiency), the activities of serum alanine aminotransferase, aspartate aminotransferase and lactate dehydrogenase may be strikingly elevated during childhood but are low during adult life. To determine the pattern of the elevated serum enzyme activities in relationship to diet, the biochemical subtype and clinical symptoms, 13 patients with DE deficiency were studied. Activities of serum aspartate and alanine transaminases, lactate dehydrogenase, and alkaline phosphatase were markedly elevated during infancy. Continued elevation of enzyme activities during childhood appeared to be related to DE deficiency in liver, but unrelated to DE deficiency in muscle. Activity elevations correlated inconsistently with diet and poorly with childhood growth rate or the presence of hypoglycaemia. The serum enzyme activities declined around puberty concomitantly with a decrease in liver size. Although periportal fibrosis and micronodular cirrhosis indicated the presence of hepatocellular damage during childhood, the decline in serum enzyme activities with age and the absence of overt hepatic dysfunction suggest that the fibrotic process may not always progress.

Lymphocytes bearing the gamma delta T-cell receptor in normal human intestine and celiac disease

Monoclonal antibodies to T-cell receptors were used to investigate the prevalence of the two distinct T-cell subpopulations (TCR alpha beta+ and TCR gamma delta+ cells) in the intestinal mucosa of children with celiac disease (gluten-sensitive enteropathy) as compared with normal intestinal mucosa. TCR gamma delta+ cells were rarely identified in the epithelium of human fetal or normal postnatal intestine and few were present in the lamina propria, whereas the number of distribution of TCR alpha beta+ cells closely resembled that of CD3+ cells. Compared with normal intestine, a significant increase in the number of CD3+, CD8+, TCR alpha beta+, and TCR gamma delta+ intraepithelial lymphocytes was present in celiac disease. Although the mucosal TCR gamma delta+ cells were less numerous than TCR alpha beta+ cells in celiac disease, there was a marked increase in the number of TCR gamma delta+ cells as compared with controls. The ligand recognized by the gamma delta T-cell receptor and the function of these cells have not been determined; however, these findings suggest a possible role for TCR gamma delta+ lymphocytes in mucosal immune responses and tissue injury as seen in celiac disease.

Autoimmune enteropathy and nephropathy with circulating anti-epithelial cell antibodies

We describe a child with circulating anti-epithelial cell antibodies, autoimmune enteropathy with intestinal villous atrophy, and membranous glomerulonephritis. The patient had persistent diarrhea at 6 months of age, and a small bowel biopsy showed active enteritis, villous atrophy, and crypt hyperplasia. When the patient was, 10 months of age, nephrotic syndrome developed because of membranous glomerulonephritis. Results of tests for circulating immune complexes were negative. Indirect immunofluorescence studies revealed a circulating antibody directed against renal epithelial cells. Circulating antibodies directed against normal small intestine epithelial cells were also detected by the immunoperoxidase technique. Western blot and immunoprecipitation identified a 55-kd antigen, in both small bowel and kidney, that reacted with an antibody in the patient's serum. High-dose prednisone therapy induced a clinical remission, resolution of the small bowel injury, and diminished serum anti-epithelial cell antibodies; after dose reduction, clinical relapse occurred with villous atrophy and reappearance of anti-epithelial cell antibodies. When the patient was 45 months of age, persistent diarrhea recurred despite intravenous administration of corticosteroids, cyclosporine, and total parenteral nutrition. Autoantibodies to a 55-kd epithelial cell protein are temporally related to the development of enteropathy and nephropathy. Study of similar patients is needed to determine the role of such antibodies in this disorder.

Immunology of inflammatory bowel disease: summary of the proceedings of the Subcommittee on Immunosuppressive Use in IBD

As outlined, scanty data exist with regard to immunologic therapy in children with IBD despite the fact that the pediatric population affords a unique opportunity for clinical evaluation. Children are less affected by modifying conditions such as smoking, alcohol ingestion, and the long-term use of medications, and because of their specific needs for ponderal and linear growth, children might benefit most from immunological therapy that has been proven to be steroid sparing. Therefore, clinical trials to evaluate the efficacy of 6-MP and/or azathioprine in growing children with Crohn's disease would appear to provide a fruitful avenue for collaborative research. Efforts to organize a multicenter evaluation of these agents have been initiated. The studies are crucial in evaluating the efficacy and safety of immunosuppressive therapy in the pediatric population with IBD.

Malnutrition and carbohydrate malabsorption in children with vertically transmitted human immunodeficiency virus 1 infection

The nutritional needs of children with human immunodeficiency virus infection are poorly understood. Twenty-eight children with vertically transmitted human immunodeficiency virus infection were evaluated for carbohydrate malabsorption using lactose hydrogen breath tests and d-xylose absorption studies. Lactose malabsorption was a common finding in human immunodeficiency virus-infected children and occurred in 8 of 20 patients who had no identifiable enteric pathogen. Lactose malabsorption occurred at an earlier age in human immunodeficiency virus-infected children than in an age-matched group of 45 symptomatic control children (P = 0.02). However, lactose malabsorption was not associated with higher rates of diarrhea or growth failure. Abnormalities in d-xylose absorption were not significantly associated with either diarrhea or growth failure. However, 39% of d-xylose studies (9 of 23) showed abnormal results and were significantly associated with enteric infections (P = 0.004). Abnormalities in small-bowel morphology were found in 4 of 9 children with growth failure, 3 of whom had an enteric infection and low d-xylose absorption. Lactose hydrogen breath testing and d-xylose testing showed carbohydrate malabsorption in 61% of children (17 of 28). This study demonstrates that human immunodeficiency virus-infected children are at risk for malabsorptive disorders, which are not always related to clinical symptoms. We speculate that human immunodeficiency virus may be directly involved in the development of lactose malabsorption. Carbohydrate malabsorption in human immunodeficiency virus-infected children may not be the only factor responsible for growth failure.

Cloning of a human homeobox gene that resembles a diverged Drosophila homeobox gene and is expressed in activated lymphocytes

A new homeobox gene, HB24, has been isolated from a human B-lymphocyte cDNA library. Northern blot analysis of polyadenylated RNA purified from activated human B cells revealed a single mRNA transcript of approximately 2.3 kb. Two cDNA clones were sequenced and provided 2,250 nucleotides (nt) of DNA sequence information. There is a single methionine codon-initiated open reading frame of 1,458 nt in frame with a homeobox and a CAX repeat, and the open reading frame is predicted to encode a protein of 51,659 daltons. When the homeodomain from HB24 was compared to known mammalian and Drosophila homeodomains it was found to be only moderately conserved, but when it was compared to a highly diverged Drosophila homeodomain, H2.0, it was found to be 80% identical. The HB24 mRNA was absent or present at low levels in normal B and T lymphocytes; however, with the appropriate activation signal HB24 mRNA was induced within several hours even in the presence of cycloheximide. Characterization of HB24 expression in lymphoid and select developing tissues was performed by in situ hybridization. Positive hybridization was found in thymus, tonsil, bone marrow, developing vessels, and in fetal brain. HB24 is likely to have an important role in lymphocytes as well as in certain developing tissues.

Human intestine matures as nude mouse xenograft

This report describes a novel system for the study of the development and function of human intestine. Human fetal bowel transplanted into a subcutaneous tunnel on the back of athymic nude (nu/nu) mice develops a new microcirculation within 4 weeks. Tissues undergo morphological development, become similar to adult human bowel tissue, and may survive for 6 months after transplantation. Monoclonal antibody immunoperoxidase staining shows that the epithelial and some endothelial elements are of human phenotype, but the circulating blood cells and migrating mucosal lymphocytes are of mouse origin.

Azathioprine in the treatment of children with inflammatory bowel disease

During a 6-year period, we treated 21 patients with azathioprine, 2 mg/kg/day, as an adjunct to their customary regimen. Nine patients had ulcerative colitis and 12 patients had Crohn disease; the patients' ages ranged from 3 to 17 years. The median duration of disease before the start of azathioprine therapy was 2 years, and median follow-up was 2 years. Sixteen patients seemed to respond to azathioprine therapy: six patients in each disease group had complete responses and four patients (one with ulcerative colitis and three with Crohn disease) had partial responses. Two patients with ulcerative colitis and three patients with Crohn disease did not respond. The median time until patients responded was less than 3 months for patients with ulcerative colitis and 4 months for those with Crohn disease. Reduction of corticosteroid dose was possible for all patients who responded to azathioprine therapy. Only minimal side effects were attributable to the drug. We conclude that azathioprine is an effective adjunctive agent for the treatment of inflammatory bowel disease in childhood, but because questions remain regarding its long-term safety, its use should be reserved for children with refractory disease or severe and unacceptable side effects of corticosteroids.

The distribution of T and B lymphocyte populations and MHC class II expression in human fetal and postnatal intestine

The development of the intestinal mucosal immune barrier is an important protective adaptation for postnatal life. The distribution and phenotype of T and B lymphocytes in human fetal intestine and lymphoid tissues have been characterized and compared to the distribution and phenotype of lymphocytes in postnatal intestine. The characterization of lymphocyte phenotype and MHC class II antigen distribution was done using MAb and an avidin-biotin complex immunohistochemical staining technique. Intraepithelial lymphocytes were occasionally present in fetal intestine and were primarily CD3+, CD8+. T lymphocytes were readily identified in the lamina propria of fetal intestine, but most were clustered in lymphoid aggregates. Cells identified by anti-IgA1 and anti-IgA2 were the most numerous cells of B cell lineage in the lamina propria of postnatal intestine, whereas IgM+ and IgD+ lymphocytes predominated in fetal tissues. However, IgA-bearing cells were identified in lymphoid aggregates of the intestine or spleen of some fetuses. This finding suggests that B lymphocytes can undergo Ig switching in utero. Additionally, fetal intestinal epithelial cells did not express MHC class II antigens, unlike some postnatal intestinal tissues. It is possible that postnatal events such as antigen exposure may be important for the induction of these class II antigens on intestinal epithelial cells.

Allergy-related proctocolitis in infants: diagnostic usefulness of rectal biopsy

To evaluate the diagnostic utility of rectal mucosal biopsies in infants with proctocolitis, we compared the clinical and histologic features of an allergy-related group (N = 36) with those of normal (N = 12) and inflammatory (N = 8) controls. Clinical features were nondiscriminatory among the three groups of patients, except for an increased absolute peripheral eosinophil count in the allergic group. Similarly, morphologic evidence of proctitis (cryptitis and crypt abscesses) and small or moderate numbers of eosinophils (less than or equal to 60 per ten high power fields) in the lamina propria of the biopsies did not discriminate among the three groups. However, large numbers of eosinophils (greater than 60 per ten high power fields) and eosinophils located in the muscularis mucosae or as the predominant cell in crypt abscesses were significantly associated with allergy-related disease. No histologic features of chronic colitis were noted in the allergy-related group. Thus, in tandem with the remainder of the clinical data, rectal mucosal biopsy is a useful adjunct in the diagnosis of allergic proctocolitis.

Expression of immune sensitization to epithelial cell-associated components in the cotton-top tamarin: a model of chronic ulcerative colitis

Chronic colitis is present in up to 50% of adult cotton-top tamarins, but the etiology is unknown. To explore one putative immunopathogenic pathway for the chronic colitis, we determined whether immune sensitization to macromolecules associated with mucosal epithelium of intestine (designated ECAC) had occurred in this primate species. Specifically, we sought to define (a) whether antigenic determinants associated with ECAC are present on tamarin gut epithelium in vivo; (b) if immunoglobulin, capable of binding ECAC, is detectable in tamarin serum; (c) whether the presence of ECAC-specific immunoglobulin is positively correlated with age of the animal or the severity of the colitis, or both; and (d) the number of glycoprotein fractions composing ECAC (denoted as P1 through P4) that are reactive with tamarin immunoglobulin. Expression of ECAC was found by immunofluorescence using characterized oligo-specific or monoclonal antibody: tamarin intestinal epithelium--but not lamina propria, muscularis mucosae, subserosa, or glycocalyx--demonstrated determinants of the ECAC antigen system. Furthermore, coded sera from 10 tamarins with biopsy-proven inflammation involving colonic intestinal mucosa and in which disease activity was moderate to severe showed ECAC-specific cytotoxicity of 3.6% +/- 1.6%. Test values for 9 of 10 of those animals were above the upper limit of normal for the assay (2.1%), and exceeded the level of lysis found with serum from histologically normal tamarins less than 2 yr old (less than 0.3%). When the data were reanalyzed by age of the animal, the incidence of ECAC-specific cytotoxicity correlated with age greater than 2 yr (r = 0.86, p less than 0.001). Epithelial cell-associated component-specific serum binding was confirmed by a second methodology (enzyme-linked immunosorbent assay), where the A405 for tamarins with lesions of moderate-severe grade (0.35 +/- 0.26) clearly exceeded that for young tamarins who were histologically normal (0.02 +/- 0.039) (p less than 0.05). Most of the reactivity was directed toward the P1 fraction of ECAC. Thus, immune sensitization to a fraction of macromolecules associated with colonic epithelium has been found in the cotton-top tamarin, analogous to findings in humans with chronic inflammatory bowel disease.

Esophageal adenocarcinoma 20 years after esophageal atresia repair

We report a case of esophageal adenocarcinoma 20 years after esophageal atresia repair. From one case report it is premature to recommend cancer surveillance for all esophageal atresia patients. However, the first survivors are now reaching an age when esophageal cancer related to chronic esophagitis may become more prevalent.

The alpha 1-antitrypsin gene is expressed in a human intestinal epithelial cell line

alpha 1-Antitrypsin (alpha 1-AT) is considered a typical plasma protein and a prototype of the serine proteinase inhibitor (serpin) family. It is synthesized in hepatocytes and, to a lesser extent, in macrophages. In this study we show that the alpha 1-AT gene is also expressed in human intestine and in a human colonic epithelial tumor cell line, Caco2. A single 1.6-kilobase alpha 1-AT-specific mRNA is present in jejunum and in Caco2 cells. It is identical in apparent size to that present in human hepatoma HepG2 cells but slightly smaller than that present in human macrophages, cells in which an alternative upstream transcriptional start site is used. Synthesis and secretion of alpha 1-AT in Caco2 cells is similar to that in HepG2 cells. It is synthesized as an approximately 52-kDa precursor polypeptide, converted to its mature, fully glycosylated 55-kDa form intracellularly, and the native protein is secreted with a half-time of 37 min. Functionally active alpha 1-AT is secreted into the basolateral and apical (luminal) fluid in pulse-chase labeling experiments of Caco2 cells cultured in polarized orientation on collagen-coated nitrocellulose membranes. Expression of alpha 1-AT in Caco2 enterocytes is not affected by soluble factors that regulate expression of alpha 1-AT in macrophages and hepatocytes. However, expression of alpha 1-AT increases markedly in Caco2 cells as they differentiate into enteric villous-type cells.

Surgical treatment of pancreas divisum causing pancreatitis in children

Although controversial, pancreas divisum has been implicated as a cause of acute pancreatitis when there is stenosis of the accessory papilla that drains the duct of Santorini. Over the past 5 years, four children with pancreas divisum and recurrent pancreatitis were successfully treated surgically. The diagnosis was made by endoscopic retrograde cholangiopancreatography (ERCP) in each case. Surgical treatment included sphincteroplasty to the accessory papilla to improve drainage of the duct of Santorini, opening the ampulla of Vater to expose the ostium of the duct of Wirsung to enlarge it, and cholecystectomy.

Gastrointestinal syndromes associated with food sensitivity

A wide range of clinical syndromes exist that are related to adverse reactions to dietary proteins and that affect predominantly the gastrointestinal tract of infants and children. Experimental data suggest a critical role for developmental alterations affecting intestinal permeability and the mucosal immune response that predispose to these conditions. The diagnostic and therapeutic approach to these disorders varies depending on the nature of the presumed offending antigen, the anatomic site affected, the severity of the inflammatory process, and the implications for future dietary and medical management. Ultimately, the proof that a particular dietary antigen is responsible is dependent on observing the response to oral challenge.

Long-term evaluation of esophageal and pulmonary function in patients with repaired esophageal atresia and tracheoesophageal fistula

Patients who have undergone repair of esophageal atresia and tracehoesophageal fistula as infants have been noted to have residual esophageal dysmotility and pulmonary dysfunction during their childhood years. However, limited information is available about the long-term follow-up of these patients. In this study we performed esophageal and pulmonary function studies on 12 adults who had required surgical repair of these defects in the first week of life. Most patients had symptoms of dysphagia and heartburn at time of evaluation. Pathologic gastroesophageal reflux was documented in 67% of patients and esophagitis was noted in 34%. All patients had esophageal motility abnormalities characterized by low-amplitude nonperistaltic waves throughout most of the esophagus. In addition, although most patients had no respiratory symptoms, mild restrictive lung volumes were noted in many patients. However, airflow obstruction and airway hyperreactivity were not present. These data demonstrate that clinical symptoms and abnormal esophageal manometry and pulmonary function persist well into the third and beginning of the fourth decade after repair of esophageal atresia and tracheoesophageal fistula in infancy.

Pyloric stenosis and eosinophilic gastroenteritis in infants

Eosinophilic gastroenteritis is known to cause gastric outlet obstruction in adults, but has been reported only rarely in infants presenting with pyloric stenosis, a common form of gastric outlet obstruction in children. We describe two infants who presented with classic clinical and radiographic evidence of pyloric stenosis and who were found to have histologic evidence of eosinophilic gastroenteritis on gastric antral biopsies. Their presentation is compared with the clinical and laboratory findings of 47 other infants with pyloric stenosis.

The treatment of post-operative and peptic esophageal strictures after esophageal atresia repair. A program including dilatation with balloon catheters

Nine patients, 6 weeks to 17 years of age with esophageal atresia (EA), developed esophageal strictures and were treated with 26 balloon catheter dilatations over a period of 3 years; 6 are now asymptomatic. Five of the 9 patients had suspected reflux esophagitis, confirmed in 3 by biopsy and treated medically prior to dilatation. Seven of the 9 patients had a primary anastomosis, 1 a gastric tube, and 1 a colonic interposition. Most dilatations in the group of 7 were performed with balloon (B) greater than or equal to the diameter of the distal esophagus (E) (B/E greater than or equal to 1). The 3 residually symptomatic patients include an infant dilated conservatively (B/E less than 1) to facilitate later bouginage, 1 patient with a recurrent stricture after stopping medical therapy and home bouginage, and 1 infant who had a persistent anastomotic stricture, suspected but untreated reflux esophagitis, and a perforation during the second balloon dilatation. Balloon catheter esophageal dilatation, as an alternative to bouginage, is usually a safe and effective procedure when reflux esophagitis is diagnosed and treated prior to dilatation.

The use of nifedipine for the treatment of achalasia in children

Four adolescents with achalasia were treated with nifedipine. All the patients' symptoms improved dramatically. On manometric evaluation, following oral nifedipine, the lower esophageal sphincter pressure decreased approximately 50%. No change in esophageal peristaltic activity was noted. Side effects were minimal; two patients had mild headache initially. Nifedipine, which is commonly used in adult patients with achalasia, may be beneficial for short-term symptomatic relief in children until more definitive therapy can be performed.

Chronic diarrhea associated with hypogammaglobulinemia and enteropathy in infants and children

In order to define the gastrointestinal manifestations and small intestinal structure and function in a group of infants with chronic nonspecific diarrhea and hypogammaglobulinemia, we retrospectively identified 55 such patients from a population of 518 children evaluated for chronic diarrhea over a 6-year span (10.6%). All patients had IgG levels 2.0 SD or more below the mean values for age. Patients with biochemical evidence of protein loss (enteropathy or nephropathy) were excluded. There was a 50% incidence of small intestinal mucosal injury among these patients, with a spectrum of morphological findings ranging from healing enteritis to severe active enteritis. Carbohydrate malasorption, and infection with Giardia lamblia or Clostridium difficile occurred in 34% and 24% of patients tested, respectively. These structural, functional, and infectious complications were all statistically more common in patients than in a control group of children with chronic diarrhea, normal growth, and normal immunoglobulin levels. This study suggests that immunoglobulin determination, in children who would otherwise carry a diagnosis of chronic nonspecific diarrhea, identifies a group with hypogammaglobulinemia, having an increased incidence of treatable intestinal dysfunction or infection, and a spectrum of small intestinal histologic abnormalities.