Ranitidine, 75 mg, over-the-counter dose: pharmacokinetic and pharmacodynamic effects in children with symptoms of gastro-oesophageal reflux

BACKGROUND

The use of over-the-counter antacids has increased in children under the age of 12 years, and has been followed by an apparent increase in the use of over-the-counter histamine-2 receptor antagonists. However, the pharmacokinetic and pharmacodynamic effects of over-the-counter histamine-2 receptor antagonists in the paediatric population are largely unknown.

AIM

To evaluate the pharmacokinetics and pharmacodynamics of a single dose of the over-the-counter histamine-2 receptor antagonist, ranitidine, 75 mg, in children with symptoms of gastro-oesophageal reflux disease.

METHODS

Children aged between 4 and 11 years with symptoms of heartburn suspected to be due to gastro-oesophageal reflux disease were recruited at six clinical centres. Following a single dose of either oral ranitidine, 75 mg (n=19), or placebo (n=10), recording of intragastric pH and serial blood sampling were carried out for 6 h.

RESULTS

The estimated pharmacokinetic parameters of ranitidine, 75 mg, were as follows: the median Cmax value of 477 ng/mL occurred within a median of 2.5 h after dosing, and the median half-life was 2.0 h. The intragastric pH began to rise approximately 30 min after dosing with ranitidine to a peak of pH; 4. The pH in the ranitidine group remained higher than that in the placebo group throughout the 6-h evaluation period. Adverse events were generally mild.

CONCLUSIONS

Ranitidine, 75 mg, significantly increased the intragastric pH in children aged 4-11 years. The pharmacokinetic and pharmacodynamic profiles were similar to those in adults. Ranitidine, 75 mg, appears to be effective for the control of intragastric acidity for 5-6 h in children aged 4-11 years.

Frequency of celiac disease in individuals with Down syndrome in the United States

Ninety-three individuals with Down syndrome (DS) were screened to investigate the prevalence of celiac disease (CD) in the United States. Five of the 93 individuals were antiendomysial antibody (EMA) positive. Of the 5 who tested positive for EMA, 4 were biopsied, 1 refused biopsy. Three of the 4 individuals biopsied manifested changes of CD on small bowel biopsy. This gives a frequency of 3.2% of confirmed CD in our DS individuals and suggests the need for periodic screening for celiac disease in this population.

Acute fatty liver of pregnancy associated with short-chain acyl-coenzyme A dehydrogenase deficiency

There is a correlation between pregnancy complications such as acute fatty liver of pregnancy and long-chain 3-hydroxyacyl-coenzyme A dehydrogenase (LCHAD) deficiency. We diagnosed another fatty acid beta-oxidation defect, short-chain acyl-coenzyme A dehydrogenase deficiency, in an infant when evaluating him because his mother had acute fatty liver of pregnancy. Other beta-oxidation defects, in addition to LCHAD deficiency, should be considered in children born after pregnancies complicated by liver disease.

New developments in the pathophysiology, clinical spectrum, and diagnosis of disorders of fatty acid oxidation

Fatty acid oxidation disorders are among the most common inborn errors of metabolism affecting infants and children. Recognition of this family of defects is critical because careful dietary monitoring, avoidance of fasting, and prompt intervention during common childhood illness can prevent catastrophic cardiac and metabolic decompensation. This review focuses on new molecular and clinical diagnostic aspects of several of these disorders. Recent papers highlight the recognition that the clinical spectrum of disorders of fatty acid oxidation goes far beyond the stereotypical Reyes-like presentation or cardiomyopathy, and now encompasses more cases of sudden infant death syndrome, fulminant hepatic failure, and severe complications during pregnancy.

Acylcarnitines in plasma and blood spots of patients with long-chain 3-hydroxyacyl-coenzyme A dehydrogenase defiency

The acylcarnitines in plasma and blood spots of 23 patients with proven deficiency of long-chain 3-hydroxyacylcoenzyme A dehydrogenase were reviewed. Long-chain 3-hydroxyacylcarnitines of C14:1, C14, C16 and C18:1 chain length, and long-chain acylcarnitines of C12, C14:1, C14, C16, C18:2 and C18:1 chain length were elevated. Acetylcarnitine was decreased. In plasma, elevation of hydroxy-C18:1 acylcarnitine over the 95th centile of controls, in combination with an elevation of two of the three acylcarnitines C14, C14:1 and hydroxy-C16, identified over 85% of patients with high specificity (less than 0.1% false positive rate). High endogenous levels of long-chain acylcarnitines in normal erythrocytes reduced the diagnostic specificity in blood spots compared with plasma samples. The results were also diagnostic in asymptomatic patients, and were not influenced by genotype. Treatment with diet low in fat and high in medium-chain triglyceride decreased all disease-specific acylcarnitines, often to normal, suggesting that this assay is useful in treatment monitoring.

Sacrosidase therapy for congenital sucrase-isomaltase deficiency

BACKGROUND

The purpose of this study was to determine if sacrosidase, a liquid produced from Saccharomyces cerevisiae containing 6000 IU of sucrase activity per mg protein, prevented symptoms of diarrhea, abdominal cramps, gas, and bloating in patients with congenital sucrase-isomaltase deficiency (CSID) consuming a normal sucrose and carbohydrate-containing diet.

METHODS

Twenty-eight children (aged 5 months to 11 years) underwent a randomized, double-blind trial consisting of two phases: 1) three sucrose breath H2 tests with three single-dose treatments (placebo, sacrosidase, and sacrosidase plus milk), and 2) a dose-response phase consisting of four multidose treatments, each for 10 days of full-strength sacrosidase, 1:10 dilution, 1:100 dilution, and 1:1000 dilution. Patients who weighed less than or equal to 15 kg received a dose of sacrosidase and those who weighed more than 15 kg received 2 ml. For the dose-response phase each patient consumed a normal diet. The number of stools and severity of symptoms were recorded daily for each concentration of sacrosidase administered and compared to a baseline period during which the patient took no sacrosidase and consumed a sucrose/starch-free diet. Data were analyzed using an ANOVA model and the nonparameter Wilcoxon signed-rank test.

RESULTS

Breath H2 excretion decreased significantly when patients received sacrosidase or sacrosidase plus milk compared to placebo during sucrose breath tests. During the dose-response phase significant treatment differences were observed between the two higher concentrations and the two lower concentrations of sacrosidase for both total stools (p < 0.001) and total symptom score (p = 0.003). Higher concentrations of sacrosidase were associated with fewer stools and a greater number of formed or hard stools compared to lower concentrations and compared to the baseline period. Higher concentrations were also associated with fewer symptoms of gas, abdominal cramps, or bloating, but no differences in vomiting. The only significant adverse event was wheezing in one child with a history of asthma.

CONCLUSIONS

Sacrosidase is a safe, effective, well-accepted treatment to prevent gastrointestinal symptoms in patients with CSID consuming a normal diet.

Mitochondria and childhood liver diseases

The newly recognized mitochondrial hepatopathies should be considered in the differential diagnosis of acute and chronic liver disease in childhood. It may appear as neonatal liver failure, delayed onset liver failure in early childhood or as a multisystemic process. Comparison of features of several of the known primary mitochondrial hepatopathies is provided in Table 5. Secondary mitochondrial hepatopathies are examples of the critical importance of mitochondrial function in the pathogenesis of liver injury. Our improved understanding of the role of the mitochondria in cellular necrosis and apoptosis opens the way for development of new therapeutic approaches to several hepatic disorders. Primary mitochondrial hepatopathies (especially the respiratory chain defects) should be considered in any child with liver disease and neuromuscular involvement, multisystemic disease, lactic acidosis or rapidly progressive disease, and when hepatic steatosis is the dominant histologic finding on examination of a liver specimen. Current therapies are inadequate; improved therapeutic strategies are needed for these disorders. Some patients with respiratory chain defects limited to the liver have had successful liver transplantation. This field is in evolution and will undoubtedly provide new and important developments as the next millennium begins.

Disorders of the mitochondria

Recent advances in our understanding of the structure and function of mitochondria have led to the recognition that inherited and acquired mitochondrial dysfunction may be responsible for diseases affecting the liver and other organ systems. Mitochondrial health may also determine hepatocyte survival in other hepatic disorders not directly related to the mitochondrion. Primary mitochondrial hepatopathies are conditions in which there are inherited defects in structure or function of the mitochondria, most of which involve the respiratory chain and oxidative phosphorylation, fatty acid oxidation, the urea cycle, and other pathways confined to mitochondria. Maternally inherited mutations or deletions of the mitochondrial genome, or putative nuclear gene mutations encoding electron transport proteins, cause defective electron transport, oxidative stress, impaired oxidative phosphorylation, and other metabolic derangements that lead to hepatic failure or chronic liver dysfunction in affected children. The mitochondrial DNA (mtDNA) depletion syndrome, which similarly leads to liver failure and neurologic abnormalities, is caused by a putative nuclear gene that controls mtDNA replication or stability. Other proven or suspected primary mitochondrial hepatopathies include Pearson's marrow-pancreas syndrome, Alpers disease, mitochondrial neurogastrointestinal encephalomyopathy syndrome, and Navajo neuropathy. Secondary mitochondrial hepatopathies are conditions in which the mitochondria are major targets during liver injury from another cause, such as metal overload, certain drugs and toxins, alcoholic liver injury, and conditions of oxidant stress. Diagnosis of mitochondrial dysfunction may be difficult with currently available tools, however, elevated blood lactate: pyruvate ratios or arterial ketone body ratios with characteristic liver histology are initial tests. Measuring respiratory chain enzyme activities, mtDNA levels, and searching for mtDNA mutations and deletions are more specific tests. Treatment of these disorders is currently empirical, involving agents that may improve the redox status of mitochondria, promote electron flow, or act as mitochondrial antioxidants. Liver transplantation has occasionally been successful in patients who lack other systemic involvement.

Gastric graft-versus-host disease: a blinded histologic study

Acute graft-versus-host disease (GvHD) of the upper gastrointestinal (GI) tract is common after allogeneic bone marrow transplantation (BMT). However, diagnosis cannot be made on clinical presentation and endoscopic findings alone, because these are nonspecific, and histologic confirmation is often desirable. The diagnosis of gastric GvHD is often based on subtle findings with considerable potential for variability in interpretation. Evaluation of the reproducibility of diagnosis and recognition of histologic features of gastric GvHD was based on blinded review of 56 gastric biopsies (24 from patients with allogeneic BMT or unrelated umbilical cord blood transplantation and 32 control biopsies from patients who did not undergo BMT, of whom eight had active GI cytomegalovirus [CMV] infection). Histologic criteria for GvHD were apoptosis and gland destruction, sparse inflammatory infiltrate, and granular eosinophilic debris in dilated glands. Seventeen patients (22 biopsies) were judged to have clinical GvHD on the basis of skin or liver involvement and GI symptoms without other known cause. Eighteen of these 22 gastric biopsies were classified as GvHD by at least two of the three pathologists on initial review. Blinded histologic diagnosis of GvHD had a positive predictive value of 69%, a sensitivity of 82%, and specificity of 76%. False-positive results occurred in CMV gastritis, human immunodeficiency virus (HIV) infection, primary immunodeficiency, and after renal transplantation. Of individual features, granular debris in glands was a specific (94% specificity), but insensitive (41% sensitivity) marker for GvHD. Distinction between GvHD and CMV infection can be difficult, and GvHD can be confused with changes seen in HIV infection and other immunodeficiency states.

Activated eosinophils in esophagitis in children: a transmission electron microscopic study

BACKGROUND

Esophagitis in infants and children is often characterized by eosinophilic inflammation. The underlying pathophysiologic mechanisms leading to this type of inflammation, and the role of eosinophils in the clinical expression of esophagitis, are unknown. The purpose of this study was to demonstrate the ultrastructural activation state of eosinophils in esophagitis in infants and children.

METHODS

Standard transmission electron microscopy was used to examine endoscopic esophageal biopsy material from patients with and without esophagitis, as defined by standard histologic criteria.

RESULTS

Twelve esophagitis and three control cases were studied. In patients with esophagitis, electron microscopy revealed numerous eosinophils throughout the mucosa and invariably demonstrated signs of activation, including inversion of core-to-matrix densities and lucency of granule core protein. Eosinophils in an activated state were seen in active diapedesis through vascular endothelium into the mucosa. Eosinophils were sometimes seen in proximity to lymphocytes. Biopsies of control patients did not demonstrate eosinophils.

CONCLUSIONS

Eosinophils present in esophagitis are activated by electron microscopic criteria, and can been seen in an activated state entering into the mucosa. This suggests that eosinophils play an active role in the pathophysiology of this disorder, and that proinflammatory factors are present that selectively recruit and activate eosinophils in esophagitis in children.

Recurrence of nonalcoholic steatohepatitis in a liver transplant recipient

A 42-year-old white man with morbid obesity and hypertriglyceridemia was noted to have nonalcoholic steatohepatitis (NASH) at the time of a laparoscopic cholecystectomy for presumed gallstone pancreatitis. His postoperative course was complicated by a 50-kg weight loss and continued right upper quadrant pain. Repeat liver biopsy revealed NASH with accompanying micronodular cirrhosis. Due to progressive fatigue, he underwent an orthotopic liver transplantation complicated by a 36-kg weight gain. Sixteen months posttransplantation, a liver biopsy revealed the recurrence of NASH. Screening for defects in fatty acid oxidation proved negative.

Acute fatty liver of pregnancy, hemolysis, elevated liver enzymes, and low platelets syndrome, and long chain 3-hydroxyacyl-coenzyme A dehydrogenase deficiency

BACKGROUND

The similarity of the hepatic pathology in acute fatty liver of pregnancy (AFLP) to that seen in children with inherited disorders of intramitochondrial fatty acid oxidation (FAO) suggests that there may be a genetic basis for some cases of AFLP.

OBJECTIVE

The purpose of this study was to examine patients with AFLP and their offspring to determine if there were women with AFLP who were heterozygous for the FAO defect, long chain 3-hydroxyacyl CoA dehydrogenase (LCHAD) deficiency.

METHODS

We evaluated 12 women previously diagnosed with AFLP. Provocative fasting studies and skin biopsies for examination of their cultured skin fibroblasts were performed to search for a generalized defect in FAO both in vivo and in vitro. Cultured skin fibroblasts from AFLP patients, their children, and their husbands were also examined specifically for LCHAD activity.

RESULTS

Of 12 women with a previous episode of AFLP, eight had reduced LCHAD activity consistent with being heterozygous for LCHAD deficiency. The eight heterozygotes had a total of nine pregnancies complicated by AFLP. In seven of those nine pregnancies, the women developed severe preeclampsia and hemolysis, elevated liver enzymes, and low platelets (HELLP) syndrome. Of the nine offspring delivered from these pregnancies, four were confirmed to be affected with homozygous LCHAD deficiency. Three other deceased infants were presumed to be LCHAD-deficient based on clinical findings, postmortem examination, and confirmed heterozygote parents. The remaining two infants delivered after pregnancies complicated by AFLP had LCHAD activity in the heterozygous range and are healthy at 18 and 24 months of age. Consistent with the known autosomal recessive nature of this defect, five tested husbands of LCHAD heterozygous women with a history of AFLP and affected infants also showed reduced LCHAD activity.

CONCLUSIONS

These studies indicate that a significant subgroup of women with AFLP are heterozygous for LCHAD deficiency and that careful observation of their offspring for signs of this disorder is warranted. Severe preeclampsia appears to increase the risk of AFLP in LCHAD heterozygous women.

Fecal short-chain fatty acids in patients with diarrhea-predominant irritable bowel syndrome: in vitro studies of carbohydrate fermentation

Colonic bacterial production of short-chain fatty acids (SCFA) plays an important role in the salvage of unabsorbed carbohydrate and in colonic absorption of electrolytes and water. The objective of this study was to determine whether patients with diarrhea-predominant irritable bowel syndrome (DP-IBS) have a different pattern and rate of fermentation of carbohydrate and fiber to SCFA compared with controls. Fecal homogenates from 10 patients with DP-IBS and 10 age-matched controls were studied. SCFA were measured by gas chromatography in baseline fecal samples and in fecal homogenates in an in vitro anaerobic fermentation system after incubation with no additional substrate, lactulose, potato starch, citrus pectin, and hemicellulose over a 24-hour period. Net SCFA production rates were calculated for the first 6 h of the incubation period. Patients with DP-IBS had a consistently different pattern of less total SCFA, a lower percentage of acetate (p < 0.05), and a higher proportion of n-butyrate (p < 0.05) than controls. In stool homogenates from both controls and DP-IBS patients, lactulose fermentation resulted in the highest rate of SCFA production followed by pectin, starch, and hemicellulose. However, at all time points, the fecal homogenates from controls generated a higher concentration of total SCFA, acetate, and propionate with all substrates tested. SCFA production rates were higher in controls incubated with lactulose, starch, and hemicellulose. The fecal SCFA profile of patients with DP-IBS is characterized by lower concentrations of total SCFA, acetate, and propionate and a higher concentration and percentage of n-butyrate. Fecal flora from these patients produced less SCFA in an in vitro fermentation system in response to incubations with various carbohydrates and fibers. Differences in SCFA production by colonic bacterial flora in patients with DP-IBS may be related to the development of gastrointestinal symptoms.

Maternal acute fatty liver of pregnancy associated with fetal trifunctional protein deficiency: molecular characterization of a novel maternal mutant allele

Acute fatty liver of pregnancy (AFLP) is a devastating late gestational complication with many similarities to the inherited disorders of mitochondrial fatty acid oxidation. We report the molecular defects in a woman with AFLP and her infant who subsequently was diagnosed with trifunctional protein (TFP) deficiency. We used single-stranded conformation variance and DNA sequence analyses of the human TFP alpha-subunit gene, which encodes the long chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) activity, to demonstrate a C to T mutation (C1678T) in exon 16 present on one allele in the mother and the affected infant. This creates a premature termination codon (R524Stop) in the LCHAD domain. Using reverse transcriptase-PCR amplification of the alpha-subunit mRNA from cultured fibroblasts, we demonstrated that transcripts containing this R524Stop mutation are present at very low levels, presumably because of rapid mRNA degradation. The affected infant also had the common E474Q mutation (nucleotide G1528C) on the second allele. Thus, he is a compound heterozygote. The father and two normal siblings are heterozygous for this E474Q mutation. This initial delineation of the R524Stop mutation provides evidence of the heterogeneity of genetic defects responsible for TFP deficiency and AFLP.

Relationship of interleukin-1 receptor antagonist to mucosal inflammation in inflammatory bowel disease

Previous work has suggested that the interleukin-1 (IL-1) receptor antagonist, IL-1ra, may regulate mucosal inflammation in inflammatory bowel disease. The present study assessed the relationship of mucosal IL-1ra levels to histologic severity of inflammation and the related proinflammatory cytokines IL-1 beta and IL-6 in children with inflammatory bowel disease. Colonic biopsy specimens from 29 patients with ulcerative colitis, 27 with Crohn's disease, and 24 noninflammatory control subjects were assayed for IL-1ra, IL-1 beta, and IL-6 by enzyme-linked immunosorbent assay. Histologic activity was graded as none, mild, moderate, or severe. Mucosal IL-1 beta levels, but not IL-1ra levels, were significantly elevated in moderate/severely inflamed biopsies from patients with either ulcerative colitis (p < 0.01) or Crohn's disease (p < 0.001) compared with those with none/mild inflammation. The mucosal molar ratio of IL-1ra/IL-1 beta was significantly lower for moderate/severe inflammation compared with none/mild inflammation for patients with ulcerative colitis (p < 0.05) and Crohn's disease (p < 0.01). The mucosal IL-1ra/IL-1 beta ratio was similar in controls to none/mild inflamed biopsies from subjects with either ulcerative colitis or Crohn's disease. Our observations suggest that increasing mucosal inflammation in inflammatory bowel disease in children is associated with a decrease in the "normal" effective IL-1ra/IL-1 beta ratio in which IL-1ra predominates. The importance of this abnormality to the pathogenesis of inflammatory bowel disease awaits further study.

Cyclosporine for the treatment of fulminant ulcerative colitis in children. Immediate response, long-term results, and impact on surgery

PURPOSE

Emergency surgery for fulminant colitis is often complicated by high-dose steroid therapy, poor nutrition, and psychologic maladjustment. Cyclosporine is effective for fulminant ulcerative colitis in adults, resulting in avoidance of immediate surgery in 75 percent of patients and a 55 percent long-term remission rate. Over the last five years, we studied the effectiveness of cyclosporine in children with fulminant colitis.

METHODS

Fourteen patients with ulcerative colitis (age, 7-20 years) received cyclosporine after satisfying the following criteria: 1) greater than five bloody diarrheal stools per day; 2) severe abdominal pain; 3) no improvement after ten days of bowel rest, 4) intravenous methylprednisolone (1-2 mg/kg/day); and 5) parenteral nutrition. Treatment was begun with oral cyclosporine (4.6-9.6 mg/kg/day), and the dose was adjusted to achieve whole blood trough levels measured with a monoclonal radioimmunoassay between 150 and 300 ng/ml. If improved, patients were discharged on oral cyclosporine, prednisone, and a regular diet.

RESULTS

Eleven of 14 patients (78 percent) responded within two to nine days and were able to consume a normal diet, had three or less soft stools per day, and had no pain. One did not respond after ten days and underwent an ileal pouch-anal anastomosis procedure. Two patients elected surgery after 20 days of therapy and a partial response. Of 11 patients who left the hospital, 4 had recurrent symptoms after 2 to 11 months of taking therapeutic doses of cyclosporine and 3 flare ups while weaning from cyclosporine after 4 to 8 months. Three patients have been weaned from cyclosporine after 8 to 13 months and have remained in remission from six months to five years. One patient is about to complete a six-month course of cyclosporine. Overall ten (72 percent) have undergone surgery, including 7 of 11 who responded initially to cyclosporine and left the hospital. Weight (P < 0.001), albumin (P < 0.01), erythrocyte sedimentation rate (P > 0.05), and prednisone dose (P < 0.001) improved significantly in the seven patients on cyclosporine who responded initially, left the hospital, and subsequently underwent surgery.

CONCLUSIONS

Cyclosporine is effective in achieving clinical remission in 80 percent of children with refractory fulminant colitis; however, within one year, most initial responders will require colectomy because of a flare up of the disease. In a majority of patients, the role of cyclosporine therapy is to rapidly ameliorate symptoms and prevent precipitous colectomy, improve nutrition and psychologic adaptation, and reduce the steroid dose leading to surgery in a well-prepared patient.

Characterization of symptoms in children with recurrent abdominal pain: resemblance to irritable bowel syndrome

We sought to prospectively characterize and compare the symptoms of children > or = 5 years of age with recurrent abdominal pain to previously established criteria for irritable bowel syndrome (IBS) in adults. For all eligible subjects, a detailed questionnaire concerning characteristics of abdominal pain and defecatory pattern was completed at presentation. In addition, a battery of screening tests was performed and additional evaluation was done at the discretion of their physician. In all, 227 subjects fulfilled the entrance criteria, but 56 were subsequently excluded because of diagnoses of inflammatory bowel disease (nine cases), lactose malabsorption (46 cases), or celiac disease (one case). Of the remaining 171 patients, 117 had IBS symptoms. In the IBS subjects, lower abdominal discomfort (p < 0.001), cramping pain (p < 0.0009), and increased flatus (p < 0.0003) were more common, whereas dyspeptic symptoms such as epigastric discomfort (p < 0.003), pain radiating to the chest (p < 0.009), and regurgitation (p < 0.02) were more common in the non-IBS subjects. Our study not only confirms the clinical heterogeneity of children with recurrent abdominal pain but also concomitantly demonstrates that most children with this disorder have symptoms that fulfill the standardized criteria for IBS in adults. The identification of subgroups of children with recurrent abdominal pain can provide a framework for the diagnosis of functional bowel disease as well as establish the need for invasive and expensive tests.

The molecular basis of pediatric long chain 3-hydroxyacyl-CoA dehydrogenase deficiency associated with maternal acute fatty liver of pregnancy

Mitochondrial long chain fatty acid beta-oxidation provides the major source of energy in the heart. Deficiencies of human beta-oxidation enzymes produce sudden, unexplained death in childhood, acute hepatic encephalopathy, skeletal myopathy, or cardiomyopathy. Long chain 3-hydroxyacyl-CoA dehydrogenase [LCHAD; long-chain-(S)-3-hydroxyacyl-CoA:NAD+ oxidoreductase, EC 1.1.1.211] catalyzes the third step in beta-oxidation, and this activity is present on the C-terminal portion of the alpha subunit of mitochondrial trifunctional protein. We used single-stranded conformation variance analysis of the exons of the human LCHAD (alpha subunit) gene to determine the molecular basis of LCHAD deficiency in three families with children presenting with sudden unexplained death or hypoglycemia and abnormal liver enzymes (Reye-like syndrome). In all families, the mothers had acute fatty liver and associated sever complications during pregnancies with the affected infants. The analysis in two affected children revealed a G to C mutation at position 1528 (G1528C) of the alpha subunit of the trifunctional protein on both alleles. This is in the LCHAD domain and substitutes glutamine for glutamic acid at position 474 of mature alpha subunit. The third child had this G1528C mutation on one allele and a different mutation (C1132T) creating a premature termination codon (residue 342) on the second allele. Our results demonstrate that mutations in the LCHAD domain of the trifunctional protein alpha subunit in affected offspring are associated with maternal acute fatty liver of pregnancy. This is the initial delineation of the molecular basis of isolated LCHAD deficiency.

Effect of infant formula on stool characteristics of young infants

BACKGROUND

Many infants are switched between multiple formula preparations early in life because of perceived abnormalities in stooling pattern as well as gastrointestinal symptoms.

OBJECTIVE

To investigate the relationship between the type of formula consumed and the stooling characteristics and gastrointestinal symptoms of young infants.

METHODS

Healthy 1-month-old infants were fed one of four commercial formula preparations (Enfamil, Enfamil with Iron, ProSobee, and Nutramigen) for 12 to 14 days in a prospective double-blinded (parent/physician) fashion. Parents completed a daily diary of stool characteristics as well as severity of spitting, gas, and crying for the last 7 days of the study period. A breast-fed infant group was studied as well.

RESULTS

Two hundred eighty five infants were enrolled and 238 completed the study. Infants receiving breast milk or Nutramigen had twice as many stools as other formula groups (P < .001). Infants receiving ProSobee had hard/firm stools more often than breast-fed or other formula-fed groups (P < .00001). Watery stools were more common in infants fed Nutramigen than other formula groups (P < .04). Green stools were more common in 12 mg/L iron preparations (Enfamil with iron, ProSobee, Nutramigen) than in those with 1 mg/L (Enfamil, breast milk) (P < .00001). Spitting, gassiness, and crying were of equal severity in all formula groups.

CONCLUSIONS

The interpretation of stool frequency, color, and consistency must take into account the infant's formula type as significant variations in normal infants occur. Parental education on the range of infant stooling characteristics as well as the common occurrence of spitting, gas, and crying may alleviate concern for formula intolerance and underlying gastrointestinal disease.

Infant colic. A pediatric gastroenterologist's perspective

Colic is a syndrome of persistent crying in infants, with multiple causes. In most cases, it is within the spectrum of normal variability in infant behavior and can be treated with reassurance, education, and counseling about appropriate parental responses. In a minority of cases, careful analysis of the crying pattern and other infant behaviors may suggest an underlying gastrointestinal problem that may be amenable to more specific treatment. This article explores the evidence supporting the use of crying and behavioral diaries to determine an appropriate response to each colicky infant.

Characterization of circulating interleukin-1 receptor antagonist expression in children with inflammatory bowel disease

The cytokines IL-1 beta and IL-6 appear to be important in the pathogenesis of inflammatory bowel disease (IBD). Recently, a naturally occurring interleukin-1 receptor antagonist, designated IL-1ra, which inhibits IL-1 beta activity in vitro and in vivo has been described. The purpose of the present study was to assess the circulating levels and relative relationships of IL-1ra, IL-1 beta, and IL-6 in children with IBD of varying severity. Serum/plasma samples were obtained from 32 children with ulcerative colitis, 45 with Crohn's disease, and 24 control patients. Cytokine assays were performed by enzyme-linked immunoassay. IL-1ra levels were significantly elevated in children with ulcerative colitis or Crohn's disease of moderate/severe activity compared to patients with inactive/mild IBD or control subjects (P < 0.001). IL-1 beta was only detectable in the circulation of two subjects with severe colitis (one ulcerative colitis, one Crohn's disease), and both had extremely elevated IL-1ra levels. IL-1ra levels were significantly related to IL-6 levels for patients with IBD (P < 0.00001). Our results suggest that circulating IL-1ra appears in increasing concentrations in children with mounting degrees of disease severity as determined by clinical scoring methods as well as by the level of IL-6. Future work will need to address the clinical and prognostic value of measuring circulating IL-1ra in individuals with inflammatory bowel disease.

Delta 10 ppm versus delta 20 ppm: a reappraisal of diagnostic criteria for breath hydrogen testing in children

OBJECTIVE

To reevaluate the timing and level of rise in breath hydrogen (H2) excretion following oral lactose challenge in children with respect to the subsequent development of symptoms consistent with lactose intolerance.

METHODS

Breath hydrogen test (BHT) data from 581 individuals < 19 yr of age (mean age 7.4 yr), all of whom had a fasting baseline breath H2 concentration of < 20 ppm, were reviewed. All subjects ingested 2 g/kg lactose (maximum 50 g) and had breath H2 analysis at 30-min intervals for 3 h. Symptoms of abdominal pain, bloating, gas, and diarrhea were monitored.

RESULTS

Seventeen percent of subjects had no H2 detectable in their breath at any time, 41% had a rise < 10 ppm from baseline, 6% increased 10-19 ppm, and 36% had a rise > or = 20 ppm. Symptom development (gas, bloating, abdominal pain, diarrhea) was similar in the non-H2 excretors, the delta < 10 ppm, and the delta 10-19 ppm groups. Compared to the < 10 ppm or < 20 ppm groups, subjects with a rise of > or = 20 ppm were more likely to develop diarrhea (p < 0.0001), gas (p < 0.0001), bloating (p < 0.0001), and abdominal pain (p < 0.0001). Symptoms were more common in the > or = 20 ppm group than in the delta 10-19 ppm group (p < 0.02 for diarrhea, p < 0.0001 for gas, bloating, and abdominal pain). Fifty-three percent of subjects with a rise in breath H2 < 20 ppm reported symptoms during or after the BHT, and 9% of those with a rise > or = 20 ppm were asymptomatic.

CONCLUSION

A rise of breath H2 concentration of > or = 20 ppm over baseline appears to correlate better with subsequent symptom development than does > or = 10 ppm. However, the frequently poor association between symptoms of lactose intolerance and breath H2 excretion suggest caution in the interpretation of the clinical significance of the BHT.

Severe upper gastrointestinal bleeding in healthy full-term neonates

Severe upper gastrointestinal bleeding is unusual in newborns, and is usually seen in sick premature infants. We report on three healthy full-term neonates who, after uneventful deliveries, presented with profuse bleeding in the first 48 h of life. Two infants had duodenal ulcers and one had diffuse hemorrhagic gastritis. All three patients responded to conservative medical therapy and have shown no recurrence of symptoms during a follow-up period of 1-4 yr.

Acute fatty liver of pregnancy and long-chain 3-hydroxyacyl-coenzyme A dehydrogenase deficiency

The pathogenesis of acute fatty liver of pregnancy is unknown, but similarities in the clinical presentation and the histological appearance of the liver with those found in children with metabolic defects in the intramitochondrial beta-oxidation pathway of the liver suggest that a disturbance in hepatic fatty acid oxidation may play a role. We report a woman with acute fatty liver of pregnancy who gave birth to a seemingly normal full-term infant who was seen at 4 mo of age with hypoglycemia, coma and profound hepatic steatosis. The infant had a defect in fatty acid oxidation, long-chain 3-hydroxyacyl-coenzyme A dehydrogenase deficiency, and the mother proved to be heterozygous for this metabolic condition. We hypothesize that the interaction of an affected fetus with a female heterozygous for this defect in fatty acid oxidation in the late third trimester accounts for some cases of acute fatty liver of pregnancy.

Fecal short-chain fatty acids in children with inflammatory bowel disease

Nutrition of colonic epithelial cells (colonocytes) is maintained by luminal short-chain fatty acids (SCFAs), chiefly by n-butyrate. The importance of SCFAs for the maintenance of colonic epithelium has been demonstrated in animal models of colitis produced by rectal instillation of an inhibitor of SCFA oxidation and in patients with diversion colitis in whom a segment of colonic epithelium was deprived of contact with luminal SCFAs. We measured fecal SCFAs and lactate in children with ulcerative colitis (UC; n = 17) and with Crohn's disease with ileocolonic involvement (CD; n = 22) and age-matched controls (n = 12) by a vacuum-distillation, gas chromatographic method. Fecal SCFA concentrations were correlated with scores of clinical disease activity. Patients with UC and CD had a decrease in the fecal concentration of acetate (p < 0.05) and an increase in n-butyrate (p < 0.01) compared with controls. No significant changes in fecal lactate were seen. A comparison of inactive- or mild-UC patients with moderate or severe-UC patients yielded major differences in SCFA concentrations with n-butyrate increased in inactive and mild UC well above control values and total SCFA and acetate decreased in moderate and severe UC below control levels. Raised concentrations of fecal n-butyrate may reflect impaired utilization of this SCFA in the colon of patients with mild UC and Crohn's disease with colonic involvement. Whether this defect is primary or secondary to inhibitors in the colonic lumen, due to impaired transport of n-butyrate into the cell or defective metabolism within the cell, or specific to inflammatory bowel disease remains to be explored.

Gastrointestinal bleeding in children

This article reviews the differential diagnosis, diagnostic approach, and selected therapeutic interventions employed in children with gastrointestinal bleeding. The focus of this article is on the presenting features of various bleeding lesions and an organized and efficient use of diagnostic and therapeutic modalities.

Percutaneous endoscopic placement of the "button" gastrostomy tube as the initial procedure in infants and children

Percutaneous endoscopic gastrostomy (PEG) tube placement is routinely performed in children with special nutritional needs. For convenience and cosmetic reasons, many parents prefer a skin-level, nonrefluxing, ("button") gastrostomy tube. After healing of the track, a button gastrostomy tube can replace a PEG but this requires a second procedure. This study assessed the technique and complication rate of placement of a button gastrostomy tube mounted for endoscopic placement as the initial procedure. Seventeen patients (10 males), ages 4 months to 12 years were studied. All patients underwent successful placement of the button under conscious sedation using a standard endoscopic push technique. In the first 10 patients, an 18 French device was used. Four patients developed migration of the device into the track between 9 and 55 days after placement and the button was removed. Migration was preceded or accompanied by a wound infection in 3 of the 4 patients. In the next 7 patients, a larger, 24 French button was used without any wound infections or migration of the device. In thirteen patients with successful placement, a follow-up period of 110-450 days has revealed no further complications. Placement of the button gastrostomy tube in infants and children can be accomplished using standard endoscopic techniques. However, further study of the optimal size of the device and optimal placement procedure to prevent wound infection and migration should be undertaken.

Evaluation of liquid yeast-derived sucrase enzyme replacement in patients with sucrase-isomaltase deficiency

BACKGROUND

No enzyme replacement therapy exists for patients with congenital sucrase-isomaltase deficiency (CSID). A by-product of the manufacture of baker's yeast is a liquid preparation containing high sucrase activity. The aim of the present study was to investigate the activity and stability of this preparation and its effect on breath hydrogen excretion and gastrointestinal symptoms after sucrose ingestion in 14 patients with CSID.

METHODS

The homogeneity of yeast sucrase was studied by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and its activity was measured. Stability at various temperatures and pH ranges and in the presence of gastric aspirate, pepsin, and bovine serum albumin was assessed. Fourteen patients with CSID underwent double-blind placebo-controlled breath tests with yeast sucrase. They then completed an 8-week dose response study that used different enzyme concentrations while consuming a sucrose-containing diet.

RESULTS

Liquid yeast sucrase is highly glycosylated, contains no lactase activity, and is stable at 4 degrees C and over a wide range of pH. Pepsin digestion of the enzyme in vitro can be blunted by bovine serum albumin and by increasing the pH. Yeast sucrase reduces breath hydrogen excretion in patients with CSID who are given a sucrose load (P < 0.001) and allows most patients to consume a sucrose-containing diet.

CONCLUSIONS

Liquid yeast sucrase offers effective enzyme replacement therapy for patients with CSID.

Examination of anti-neutrophil cytoplasmic antibodies in childhood inflammatory bowel disease

The detection of anti-neutrophil cytoplasmic antibodies (ANCA), in a perinuclear fluorescence pattern, in the serum of adults with inflammatory bowel disease has recently been described to be sensitive and specific for a diagnosis of ulcerative colitis in comparison to Crohn's disease and other colitides. We have examined the sera of 41 children and adolescents with ulcerative colitis, 27 with Crohn's disease, and a control group for the presence of ANCA. Anti-neutrophil cytoplasmic antibodies were detected in the serum of 27 of 41 patients with ulcerative colitis (66%), five of 27 with Crohn's disease (19%), and in none of our control subjects or patients with functional abdominal pain. Overall, the presence of ANCA was 66% sensitive and 84% specific for a diagnosis of ulcerative colitis when compared to Crohn's disease. There was no relationship between a positive ANCA value and disease activity or other clinical indicators. We conclude that evaluation for the presence of ANCA may be a useful adjunct for the clinical assessment of patients with inflammatory bowel disease. The presence of ANCA in children and adolescents, however, will not definitively distinguish between patients with ulcerative colitis and Crohn's disease.

Portal hypertensive gastropathy in children

We endeavored to determine the frequency and clinical characteristics of portal hypertensive gastropathy (PHG) in children with cirrhotic and noncirrhotic portal hypertension. Medical records of all patients with portal hypertension undergoing upper GI endoscopy during a 7-year period were retrospectively reviewed. PHG was defined as absent, mild, or severe by previously established criteria. Twenty-two patients with portal hypertension (17 cirrhotic, 5 noncirrhotic) were identified. In the group of 17 cirrhotic patients, PHG was noted in four at initial endoscopy (three mild, one severe) and in seven (two mild, five severe) during follow-up. Severe PHG was seen in one patient with noncirrhotic portal hypertension at presentation; in two patients, mild PHG developed during follow-up. In the 14 patients in whom PHG was noted, gastric mucosal disease developed in nine in whom no sclerotherapy was performed and in five patients treated with sclerotherapy. The size of varices, history of variceal bleeding, and presence or absence of hypersplenism did not appear to be related to the development of PHG. None of seven patients with mild PHG and two of seven patients with severe PHG bled from their gastric mucosa. We conclude that PHG is commonly observed in children with cirrhotic and noncirrhotic portal hypertension. Mild PHG appears to have little clinical significance, while severe PHG may cause bleeding. PHG may develop with or without sclerotherapy.

Renal handling of carnitine in secondary carnitine deficiency disorders

Reduced plasma and tissue concentrations of carnitine, a cofactor required for fatty acid oxidation, are present in patients with inherited disorders of mitochondrial acyl-CoA oxidation that are associated with accumulations of acylcarnitines. To determine whether the secondary carnitine deficiency in these patients is due to excessive urinary loss of acylcarnitines, the development of carnitine deficiency was examined in patients with four different acyl-CoA oxidation disorders, including medium-chain and long-chain fatty acyl-CoA dehydrogenase deficiencies, isovaleric acidemia, and propionic acidemia. After a 3-mo period of treatment with oral carnitine to raise plasma total carnitine concentrations to or above normal, patients were started on a carnitine-free diet and the changes in plasma total and free carnitine levels and urinary total and free carnitine excretion were followed for 5 d. Patients with all four disorders showed a return of plasma carnitine levels and urinary carnitine excretion to baseline within 2 to 4 d. The rapidity of these changes could not be explained solely by excessive acylcarnitine wasting. Continued excretion of free carnitine in all patients indicated the additional presence of an impairment in renal transport of free carnitine. Consistent with this interpretation, estimates of renal thresholds for free carnitine gave values that were less than that for a control child in all four disorders and ranged as low as one half those reported in normal individuals. These results suggest that secondary carnitine deficiency in the acyl-CoA oxidation disorders is due to indirect as well as direct effects of accumulated acylcarnitines.(ABSTRACT TRUNCATED AT 250 WORDS)

Feeding resistance and gastroesophageal reflux in infancy

Resistance to oral feedings occurring during the course of chronic gastroesophageal reflux (GER) in infants has received little attention in the literature. Accordingly, we reviewed the clinical courses of 600 infants of < 24 months of age with GER seen over an 8-year period to determine the prevalence and course of this problem. After excluding infants with severe neurologic disease, craniofacial disorders, or a history of esophageal surgery, 25 infants were found to have resistance to oral feedings that was severe enough to warrant tube feedings for nutritional support. Sixteen of these 25 infants had a history of resistance to oral feeding antedating a diagnosis of GER, whereas nine developed resistance to feeding during the course of therapy. Gestational age, age at onset of GER symptoms, severity of GER, presence/severity of esophagitis, type of medical therapy, need for fundoplication, or postfundoplication complications were similar in these two groups. When the clinical records of these 25 infants were compared to an age- and sex-matched infant population with GER but without feeding resistance, no differences were noted in severity of GER or the presence/severity of esophagitis. However, failure to thrive and the need for fundoplication were significantly more common in the feeding resistance group (p < 0.001). Among those infants with neurodevelopmental evaluation, mild delay was seen more commonly in the infants with feeding resistance but fell short of statistical significance (p = 0.08). Our observations suggest that resistance to oral feedings is an uncommon but severe problem associated with GER in infancy.(ABSTRACT TRUNCATED AT 250 WORDS)

Relationship of functional and antigenic interleukin 6 to disease activity in inflammatory bowel disease

BACKGROUND

Intestinal and peripheral blood mononuclear cell interleukin 6 (IL-6) production in inflammatory bowel disease might present an increased quantity of IL-6 into the systemic circulation. The aim of the present study was to examine the relationship of circulatory IL-6 to the clinical and laboratory expression of inflammatory bowel disease in children.

METHODS

Sera were obtained from 26 children with ulcerative colitis, 49 with Crohn's disease, and 29 control patients. Serum functional IL-6 was measured by a bioassay and antigenic IL-6 by enzyme linked immunosorbent assay.

RESULTS

Functional and antigenic serum IL-6 levels were higher in Crohn's disease than in ulcerative colitis or controls (P < 0.0001) and higher in ulcerative colitis than controls (P < 0.04). In Crohn's disease affecting the colon, functional and antigenic serum IL-6 levels were greater than in disease limited to the small bowel (P < 0.002). Increasing disease severity was reflected by increasing antigenic but not functional IL-6 levels in both Crohn's disease (P < 0.001) and ulcerative colitis (P < 0.02). Serum antigenic IL-6 levels were related to acute phase reactants in both diseases (P < 0.001) whereas functional levels were not.

CONCLUSIONS

Our results underscore the importance of using both functional and antigenic methodologies in examining the relationship of circulating cytokines to the clinical manifestations of inflammatory bowel disease.

Ulcerative colitis and total alopecia in a mother and her son

Extraintestinal autoimmune disorders are associated with ulcerative colitis in selected patients and lend support to the theory of immune-mediated injury in inflammatory bowel disease. Rarely, alopecia areata has been associated with ulcerative colitis, and familial aggregation and an HLA association have been reported for both disorders. The occurrence of both alopecia and ulcerative colitis in a mother and son are reported with a detailed investigation of antineutrophil cytoplasmic antibodies and HLA alleles in this family. Treatment with the immunosuppressive agent cyclosporine proved beneficial in the child leading to remission of the ulcerative colitis and nascent growth of scalp and body hair.

Cytokeratin immunohistochemical examination of liver biopsies in infants with Alagille syndrome and biliary atresia

Identifying bile duct epithelium is sometimes difficult with standard histologic techniques. The availability of antibodies to specific cytokeratin (CK) intermediate filaments has allowed identification of CK expressed by bile duct epithelium. Formalin-fixed, paraffin-embedded liver tissue from five infants (aged 1-12 months) with Alagille syndrome and five infants with biliary atresia (aged 1.5-11 months) were pepsin digested then reacted with a combination of anti-cytokeratin monoclonal antibodies using an avidin-biotin immunoperoxidase technique. Liver tissue obtained at autopsy from infants without primary liver disease (aged 22 weeks gestation to 24 months) was treated similarly for comparison. Control specimens showed progression from prominent immunoreactivity of the ductal plate cells at the rim of the portal tract (22-24 weeks gestation) to incorporation of tubular ductal structures into portal tract mesenchymal tissue (26-34 weeks gestation) and formation of intensely immunoreactive mature discrete interlobular ducts with progressive loss of cytokeratin immunoreactivity of the ductal plate cells (1-24 months). In contrast, biopsies from infants with Alagille syndrome showed few immunoreactive interlobular ducts. Biopsies from infants with Alagille syndrome less than 2 months old showed only immunoreactivity of single ductal plate cells or small ductules at the periphery of the portal tracts. Biopsies from some infants greater than 3 months old showed increased numbers of immunoreactive cells in groups and anastomosing bands lacking true lumens and extending into the fibrous bridges between adjacent portal areas (neoductular proliferation).(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of the effect of a fiber-enriched formula on infant colic

Because infants with colic appear to have abdominal pain similar to that of adults with irritable bowel syndrome, who may benefit from the addition of fiber to their diet, we tested whether fiber added to infant formula would alleviate colic. Twenty-seven normal, term infants (aged 2 to 8 weeks; 14 girls) with colic, defined as crying plus fussing for more than 3 hours a day for at least 3 days of a 6-day baseline period, were enrolled. Infants were randomly assigned in 9-day periods to a sequence of placebo (Isomil formula) followed by fiber-supplemented formula (Isomil plus soy polysaccharide) (n = 12) or the reverse (n = 15). Daily diaries of crying, fussing, sleeping, formula, intake, and stooling were kept. Twenty-two infants completed three lactulose breath hydrogen tests at the end of the baseline period and after each study period. The crossover trial was followed by 30 to 35 days of use of the study formula chosen by the parents as most beneficial but unknown to the investigators. Growth was monitored throughout. Serum cholesterol, calcium, phosphate, albumin, iron, and zinc concentrations were measured at the conclusion. There were no significant differences in average daily time spent by the infants in fussing and crying during ingestion of the fiber-supplemented formula. However, parents of 18 of 27 infants chose fiber-supplemented formula as most beneficial in ameliorating symptoms of colic. While the infants were consuming fiber-supplemented formula, stool frequency increased, and breath hydrogen excretion increased significantly, in response to lactulose. Growth and serum biochemical measurements were normal in all infants. Supplementation of infant formula with the level of soy polysaccharide used in this study may have reduced crying and fussing in some infants but did not affect colicky behavior in the majority of infants, who continued to cry and fuss excessively.