Use of the recto-sigmoid index to diagnose Hirschsprung's disease.

The recto-sigmoid index on barium enema may aid in the diagnosis of Hirschsprung's disease. However, data on its reliability in different age groups are sparse. The recto-sigmoid index and transitional zone were evaluated blindly in 107 patients with diagnostic rectal suction biopsies. Patients were divided into 3 groups: neonates, infants older than 1 month, and children. The recto-sigmoid index and transitional zone agreed with the histopathologic diagnosis in 79% and 87% of the cases, respectively. Their negative predictive values reached clinical significance in infants and children but not in neonates. Their positive predictive values were not significant in any age group. The recto-sigmoid index identified 4 patients with recto-sigmoid Hirschsprung's disease whose diagnosis was missed by evaluating the transitional zone alone.

Use of infliximab in pediatric patients with inflammatory bowel disease.

BACKGROUND: The concentration of tumor necrosis factor, a proinflammatory cytokine, is increased in the gastrointestinal mucosa of patents with active Crohn's disease (CD) and ulcerative colitis (UC). Neutralization of tumor necrosis factor decreases the mucosal inflammatory response of adults with CD. Little information is available on the use of monoclonal antibody to tumor necrosis factor (infliximab) in children and adolescents with CD or UC. OBJECTIVE: To evaluate the clinical response and side effects of patients to infliximab. METHODS: A retrospective review of data regarding 18 pediatric and adolescent patients with active CD (n = 15) and UC (n = 3) poorly controlled with conventional therapy. All patients received one to six intravenous infusions of infliximab 5 mg/kg, while receiving their usual medications. RESULTS: All patients experienced clinical improvement, including decrease in the frequency of stooling and resolution of extraintestinal symptoms such as arthropathy, malaise, and skin manifestations after treatment with infliximab. All but one patient had a documented decrease in the erythrocyte sedimentation rate. Prednisone dosage was tapered in all but two patients, and discontinued in seven patients. Intravenous infusion of infliximab was well tolerated. One patient developed a rash several days after the infusion. A patient who received six infliximab infusions developed recurrent Staphylococcus aureus infections, as well as septic arthritis and chronic osteomyelitis during the follow-up period, raising the issue of the long-term safety of infliximab. CONCLUSIONS: Treatment of our patients with refractory CD and UC with infliximab was associated with remarkable clinical improvement. Although the drug may have an important role in their management, further assessment of long-term safety and efficacy is needed.

Detection of interferon regulatory factor-1 in lamina propria mononuclear cells in Crohn's disease.

BACKGROUND: The transcription factor, interferon regulatory factor (IRF)-1, is stimulated by interferon-gamma and regulates the expression of several genes implicated in the pathogenesis of inflammatory bowel disease, including interleukin-6, major histocompatibility complex class II molecules, and inducible nitric oxide synthase. Interferon regulatory factor-1 also stimulates naive CD4+ T-cells to differentiate into T-helper-1 cells, the T-cell subset that appears to be upregulated in Crohn's disease. The purpose of this study was to examine the expression of IRF-1 in the nuclei of lamina propria mononuclear cells in situ in colonoscopic biopsy specimens from pediatric patients with Crohn's disease, in patients with ulcerative colitis, and in control patients with no histopathologic abnormalities. METHODS: Archival paraffin-embedded tissue sections were obtained from 25 pediatric patients with Crohn's disease, 6 patients with ulcerative colitis, and 12 control patients who had undergone colonoscopy. Tissue sections were stained with polyclonal rabbit anti-human antisera to IRF-1 and horseradish-peroxidase-conjugated, biotinylated, goat anti-rabbit secondary antibody. Slides were scored and scores compared among patient groups using analysis of variance. RESULTS: Patients with Crohn's disease had significantly higher IRF-1 scores (95% confidence interval [CI], 1.70-2.04) than patients with ulcerative colitis (95% CI, 0.92-1.23) or control subjects (95% CI, 1.11-1.52). CONCLUSIONS: Increased expression of IRF-1 in lamina propria mononuclear cells from patients with Crohn's disease may be relevant to the pathogenesis of Crohn's disease.

Delayed diagnosis of fatal medium-chain acyl-CoA dehydrogenase deficiency in a child.

A 5-year-old white female presented with coma and died unexpectedly. She had a history of recurrent episodes of febrile illnesses associated with lethargy and coma. Postmortem investigation revealed a fatty liver, leading to a suspicion of inborn error of fatty acid oxidation. The diagnosis of medium-chain acyl-CoA dehydrogenase (MCAD) deficiency was suggested by abnormal acylcarnitine profile with increased octanoylcarnitine in the blood, and confirmed by fatty acid oxidation studies and mutation analysis in skin fibroblast cultures. This case emphasizes the need to consider fatty acid oxidation disorders in all children who present with hypoglycemia with absent or mild ketones in the urine and high anion gap metabolic acidosis.

Highly destructive perianal Crohn's disease.

This article reports a case of highly destructive perianal Crohn's disease in a 15-year-old boy who presented with fecal impaction and incontinence. Both upper and lower gastrointestinal tract endoscopy were unrevealing. Treatment with intravenous prednisolone and broad-spectrum antibiotics supplemented by enteral feeding with an elemental diet resulted in prompt recovery. However, healing of his perianal lesions began only after a diverting colostomy. Awareness of this uncommon entity is important because prompt recognition can lead to early institution of appropriate treatment and avoid further morbidity.

Analysis of carnitine esters by radio-high performance liquid chromatography in cultured skin fibroblasts from patients with mitochondrial fatty acid oxidation disorders.

Acylcarnitines are important diagnostic markers for inborn errors of fatty acid oxidation, but their analysis in body fluids may not always be reliable. Recently, disease-specific acylcarnitine profiles generated by cultured skin fibroblasts were reported to facilitate the diagnosis by localizing a specific enzymatic defect in the mitochondrial beta-oxidation pathway. Using a novel methodologic approach, fibroblasts from 16 patients with inborn errors of fatty acid oxidation and 13 control subjects were preincubated with L-[3H]carnitine to label the intracellular carnitine pool. Cells were subsequently incubated with unlabeled palmitic acid and, after methanol extraction of cells and media, labeled free carnitine and acylcarnitines were analyzed by radio-HPLC. Quantitation was based on the integrated radioactivity of individual peaks relative to the total radioactivity recovered. In control cell lines, all saturated acylcarnitines were detected, and reference values were established. With the exception of one cell line deficient in electron transfer flavoprotein, all mutant cell lines showed abnormal and disease-specific relative concentrations of acylcarnitines. Advantages of the method include use of a small number of cells, no need for trypsinization and permeabilization of cells before incubation, simple extraction without purification of the specimen before HPLC, and relatively inexpensive equipment. The method allows a focused approach to the subsequent, more laborious confirmation of a particular disease by direct enzymatic and/or molecular analysis. It remains to be established whether the method can replace widely used global measurements of fatty acid oxidation rates in vitro that do not provide specific information about the enzyme deficiency involved.

Gastroesophageal reflux and Nissen fundoplication following percutaneous endoscopic gastrostomy in children.

BACKGROUND: Abnormal gastroesophageal reflux after percutaneous endoscopic gastrostomy is a serious problem in neurologically impaired children. Protective fundoplication has been advocated. Whether esophageal pH monitoring before percutaneous endoscopic gastrostomy will predict later problems with gastroesophageal reflux is unclear. METHODS: Eighty-five mostly neurologically impaired pediatric patients who underwent percutaneous endoscopic gastrostomy were studied retrospectively regarding complications, success of nutritional rehabilitation, and the incidence of pathologic gastroesophageal reflux. Follow-up period was 1 to 4 years. Twenty-four-hour esophageal pH monitoring was performed in 46 patients before percutaneous endoscopic gastrostomy. RESULTS: There were no deaths. Two major complications occurred that required surgical intervention, and 14 minor complications occurred related to the procedure. Z-scores for weight increased significantly after percutaneous endoscopic gastrostomy. pH probe results were normal in 22 patients (group 1). Five required medical treatment for gastroesophageal reflux after percutaneous endoscopic gastrostomy, but only 1 (5%) later required Nissen fundoplication. pH probe results were abnormal in 24 patients (group 2). Nineteen required medical therapy for gastroesophageal reflux, and 7 (29%) later needed fundoplication (p < 0.05, incidence of fundoplication group 1 vs. group 2). Improvement in Z-scores was similar in patients requiring and not requiring fundoplication. CONCLUSIONS: Percutaneous endoscopic gastrostomy is a safe and effective technique for long-term nutritional support in children. Abnormal gastroesophageal reflux is common. Normal findings in an esophageal pH study before percutaneous endoscopic gastrostomy may be predictive of a favorable outcome with respect to gastroesophageal reflux. This is in contrast to patients with abnormal results in pH studies before percutaneous endoscopic gastrostomy of whom a relatively large percentage may later require fundoplication. Improved nutritional status after percutaneous endoscopic gastrostomy does not appear to have an impact on the severity of gastroesophageal reflux.

Neonatal nutritional carnitine deficiency: a piglet model.

The clinical significance of nutritional carnitine deficiency remains controversial. To investigate this condition under controlled conditions, an animal model was developed using the parenterally alimented, carnitine-deprived newborn piglet. Forty-five piglets received total parenteral nutrition for 2-3 wk that was either carnitine-free or supplemented with 100-400 mg/L L-carnitine. Blood and a muscle biopsy were taken at the initial surgery. Carnitine balance studies were performed at 11-14 d of age. Blood, liver, heart, and skeletal muscle were taken at sacrifice for analysis of carnitine, electron microscopy, and oxidation studies. Carnitine-deprived piglets were in negative carnitine balance and had lower blood, urine, and tissue levels of carnitine than carnitine-supplemented animals. There was a positive correlation between excretion and plasma concentrations of free carnitine with an apparent renal threshold between 15 and 35 micromol/L. Plasma levels were correlated with liver and heart, but not muscle, concentrations of total acid-soluble carnitine. Carnitine-deprived piglets had evidence of lipid deposition in liver and skeletal muscle and tended to have a higher incidence of muscle weakness and cardiac failure. Basal rates of oxidation of [14C]palmitate to 14CO2 and 14C-acid-soluble products were lower in liver homogenates from carnitine-deprived piglets than in those from carnitine-supplemented animals and increased in a dose-dependent fashion with the addition of L-carnitine (0, 50, and 500 micromol/L) in vitro. In summary, carnitine deprivation in the neonatal piglet resulted in low carnitine status and morphologic/functional disturbances compatible with carnitine deficiency. The described animal model appears to be suitable for the investigation of neonatal nutritional carnitine deficiency.

Isovaleric acidemia: response to a leucine load after three weeks of supplementation with glycine, L-carnitine, and combined glycine-carnitine therapy.

OBJECTIVE: To assess the effectiveness of glycine and carnitine therapy on isovaleryl conjugate excretion in isovaleric acidemia (IVA). STUDY DESIGN: Urinary isovalerylglycine (IVG) and isovalerylcarnitine (IVC) were measured from 12-hour urine specimens collected overnight from an 8-year-old patient with IVA (who had no residual activity of isovaleryl-CoA dehydrogenase in fibroblasts) before and during 3-week courses of supplementation with glycine alone (250 mg/kg per day), L-carnitine alone (100 mg/kg per day) therapy, and both of these agents combined, with a 2 gm leucine challenge performed at the end of each treatment period. RESULTS: Isovalerylglycine was the predominant metabolite excreted throughout the study, and its mean value doubled with glycine treatment. Isovalerylcarnitine excretion was minimal without carnitine supplementation. L-Carnitine therapy was associated with a 50% decline in excretion of IVG without a fully compensatory increase in IVC. The readdition of glycine to the carnitine regimen resulted in an increase in IVG excretion. Leucine challenge resulted in a 2.7- and 2.4-fold increase of IVG and IVC excretion, respectively, during L-carnitine therapy but not during glycine supplementation, and a 3.5- and 4-fold increase in excretion of both metabolites during glycine plus L-carnitine therapy. Total conjugate excretion was highest after a leucine load during combined glycine and L-carnitine therapy. CONCLUSIONS: Combined glycine and L-carnitine therapy maximally increases isovaleryl conjugate excretion during metabolic stress but not under stable conditions.

Quantitation of short- and medium-chain acylcarnitines in plasma by radioisotopic exchange/high-performance liquid chromatography.

A method for the quantitation of short- and medium-chain acylcarnitines in plasma and its clinical application are described. The method is based on enzymatic exchange of L-[3H]carnitine into the acylcarnitine pool, subsequent separation of labeled acylcarnitines by high-performance liquid chromatography, and quantitation of the radioactivity by a beta flowthrough detector. Since only acylcarnitines are detected, no sample cleanup procedure is required. Isotopic equilibrium, a prerequisite for accurate quantitation, was reached in plasma after 1 h of incubation for all acylcarnitines except isovalerylcarnitine which required a longer incubation time. No significant hydrolysis of acylcarnitines occurred during the incubation. Linearity was demonstrated after adding increasing amounts of individual acylcarnitines to plasma. The method is highly sensitive requiring no L-carnitine administration to the patient and differentiates short-chain acylcarnitine isomers. It is suitable for the detection of a number of inborn errors of organic acid and fatty acid metabolism.

Clinical and biochemical characterization of short-chain acyl-coenzyme A dehydrogenase deficiency.

OBJECTIVE: We identified two additional patients with short-chain acyl-coenzyme A (CoA), further characterized the clinical and biochemical features of this defect, and compared it with other fatty acid oxidation defects. DESIGN: We have measured the in vitro short-chain acyl-coenzyme A dehydrogenase (SCAD) activity in six affected persons with the electron-transfer flavoprotein-linked assay in the presence and absence of anti-medium-chain acyl-CoA dehydrogenase antibody. Urine organic acids, acylglycines, acylcarnitines, and radiolabeled substrate catabolism by skin fibroblasts were also examined. RESULTS: All patients had some neurologic abnormalities, including hypotonia, hypertonia, or seizures. None of the patients had episodes of hypoglycemia; in the only patient tested, fasting ketogenesis was not impaired. Four patients were initially seen in the neonatal period, two with profound metabolic acidosis and two with mild acidemia; the other two cases were recognized in infancy. Enzymatic analysis of cultured skin fibroblasts demonstrated approximately 10% activity of SCAD when compared with control fibroblasts. Gas chromatography and mass spectrometry of urine revealed that ethylmalonic acid was present in all samples but not always at elevated concentrations; methylsuccinic acid and butyrylglycine were sporadically elevated. n-Butyrylcarnitine was often found in urine and plasma. Radiolabeled substrate metabolism was reduced to 40% to 60% of control values. CONCLUSIONS: Because affected persons do not consistently excrete characteristic metabolites, the diagnosis of this enzymatic deficiency is difficult. It is necessary to collect and analyze several urine and plasma specimens when the diagnosis is being considered in patients with neurologic abnormalities suggestive of this disorder.

Population screening for medium-chain acyl-CoA dehydrogenase deficiency: analysis of medium-chain fatty acids and acylglycines in blood spots.

We have developed methods for the measurement of the medium-chain fatty acids octanoate, decanoate and cis-4-decenoate and the acylglycines n-hexanoylglycine (HG) and 3-phenylpropionylglycine (PPG) in blood spots using gas chromatography and mass spectrometry. Normal ranges were obtained for octanoate and decanoate. HG, PPG and cis-4-decenoic acid were not detected in control blood spots. In blood spots from nine patients (including two newborn) with medium-chain acyl-CoA dehydrogenase (MCAD) deficiency, all metabolites were present in elevated concentrations although PPG was close to the detection limits and there was overlap for octanoate and decanoate. The lack of detection of cis-4-decenoic acid and HG in controls suggests that these are the metabolites of choice for blood spot identification of infants with MCAD deficiency.

A new syndrome with ethylmalonic aciduria and normal fatty acid oxidation in fibroblasts.

We describe four Italian male infants with a novel clinical phenotype characterized by orthostatic acrocyanosis, relapsing petechiae, chronic diarrhea, progressive pyramidal signs, mental retardation, and brain magnetic resonance imaging abnormalities. The first symptoms appeared after the termination of breast-feeding and introduction of formula feeding. Marked persistent 2-ethylmalonic aciduria was associated with abnormal excretion of C4-C5(n-butyryl-, isobutyryl-, isovaleryl-, and 2-methylbutyryl-)acylglycines and acylcarnitines and with intermittent lactic acidosis. Short- and branched-chain plasma acylcarnitine levels were also elevated. 2-Ethylmalonic aciduria is generally regarded as being indicative of a defect in fatty acid oxidation. Extensive studies of cultured fibroblasts failed to reveal such a defect. The observation of intermittent urinary excretion of 2-ethylhydracrylic acid pointed to involvement of the isoleucine R pathway in ethylmalonate biosynthesis. This hypothesis was tentatively corroborated by the biochemical responses to an oral isoleucine challenge in two patients. However, fibroblast studies showed normal oxidation rates of (14C)isoleucine (ul), indicating that this is not a defect of isoleucine oxidation expressed in skin fibroblasts. In one of two patients tested, cytochrome c oxidase activity was partially reduced (45%) in cultured fibroblasts. This unique clinical and biochemical phenotype identifies a new metabolic encephalopathy of yet undetermined cause.