RESUMEN
The North American Society for Pediatric Gastroenterology and Nutrition published guidelines for the evaluation of children suspected of being infected with Helicobacter pylori. The stool antigen test for H. pylori, which was recently commercialized in the United States, was evaluated in two high-risk pediatric populations. The results are encouraging but should be interpreted with caution. A number of studies suggest that delayed gastric emptying may accompany a variety of disorders, or may be a cause of vomiting. The outcome of children with dyspeptic symptoms is described, and the results will be helpful in reassuring anxious parents. Studies examining the development of H, K-adenosine triphosphatase in infants and the role of enteric glial cells in infantile hypertrophic pyloric stenosis are discussed. A study of neonates with allergic gastroenteropathy suggests that this disorder may be more common in this age group than generally thought.
RESUMEN
Studies within the past year examining the mechanisms underlying infantile hypertrophic stenosis at the cellular and molecular level are reviewed. A number of new modalities, including electrogastrography, and the 13C octanoid acid breath test have been used in the study of normal and abnormal gastrointestinal motility, as well as for the characterization of patterns of development of gastric motility in early infancy. Several studies pertaining to the natural outcome, the mode of transmission, and the associated symptomatology of Helicobacter pylori were published, attesting that, despite the tremendous progress achieved in our understanding of H. pylori, important gaps remain in our knowledge of this microorganism. Newly described clinical presentations of eosinophilic gastroenteritis and food allergy will also be of interest to the reader.
RESUMEN
Sustained smooth muscle contraction is mediated by protein kinase C (PKC) through a signal transduction cascade leading to contraction. Heat-shock protein 27 (HSP27) appears to be the link between these two major events, i.e., signal transduction and sustained smooth muscle contraction. We have investigated the involvement of HSP27 in signal transduction and HSP27 association with contractile proteins (e.g., actin, myosin, tropomyosin, and caldesmon) resulting in sustained smooth muscle contraction. We have carried out confocal microscopy to investigate the cellular reorganization and colocalization of proteins and immunoprecipitation of HSP27 with actin, myosin, tropomyosin, and caldesmon as detected by sequential immunoblotting. Our results indicate that 1) translocation of Raf-1 to the membrane when stimulated with ceramide is inhibited by vasoactive intestinal peptide (VIP), a relaxant neuropeptide; 2) PKC-alpha and mitogen-activated protein kinase translocate and colocalize on the membrane in response to ceramide, and PKC-alpha translocation is inhibited by VIP; 3) HSP27 colocalizes with actin when contraction occurs; and 4) HSP27 immunoprecipitates with actin and with the contractile proteins myosin, tropomyosin, and caldesmon. We propose a model in which HSP27 is involved in sustained smooth muscle contraction and modulates the interaction of actin, myosin, tropomyosin, and caldesmon.
Asunto(s)
Colon/metabolismo , Proteínas Contráctiles/metabolismo , Proteínas de Choque Térmico/fisiología , Músculo Liso/metabolismo , Transducción de Señal/fisiología , Actinas/metabolismo , Animales , Azepinas/farmacología , Transporte Biológico , Proteínas Quinasas Dependientes de Calcio-Calmodulina/metabolismo , Proteínas de Unión a Calmodulina/metabolismo , Ceramidas/farmacología , Colon/citología , Colon/efectos de los fármacos , Citoesqueleto/metabolismo , Proteínas de Choque Térmico/metabolismo , Isoenzimas/metabolismo , Contracción Muscular/efectos de los fármacos , Contracción Muscular/fisiología , Músculo Liso/citología , Músculo Liso/efectos de los fármacos , Miosinas/metabolismo , Naftalenos/farmacología , Pruebas de Precipitina , Proteína Quinasa C/metabolismo , Proteína Quinasa C-alfa , Proteínas Proto-Oncogénicas c-raf/metabolismo , Conejos , Distribución Tisular , Tropomiosina/metabolismoRESUMEN
Over the past year, there have been continued efforts to increase our understanding of the epidemiology, natural history, and pathogenic mechanisms of Helicobacter pylori infection in children. In an attempt to delineate the spectrum of disease associated with this organism, several teams of investigators have also examined the association of H. pylori infection with other disorders, from food allergy to inflammatory bowel disease. Developmental aspects of gastric and duodenal motility, risk factors for gastrointestinal bleeding in pediatric intensive care unit patients, and the use of uncooked cornstarch in the treatment of dumping syndrome are among other topics covered in this review.
RESUMEN
BACKGROUND: alpha-Interferon is widely accepted for treatment of adults with chronic hepatitis B, but its use remains limited in children, partly because of questions regarding its cost effectiveness. The aim of this study was to evaluate the cost effectiveness of alpha-interferon for children with chronic active hepatitis B. METHODS: We estimated the cost per year of life saved by alpha-interferon therapy for three cohorts of patients with chronic active hepatitis B treated at 2, 12, or 25 years of age. We assumed that only patients with active viral replication would be treated and that alpha-interferon would prevent cirrhosis and hepatocellular carcinoma in a portion of the population treated. We calculated costs per year of life saved. Medical costs and years of life saved were discounted at 5% per year. RESULTS: With a 30% response rate to alpha-interferon, there was a net savings in both money and lives in the children's group with a minimal cost per year of life saved for adolescents ($510) and adults ($934). Years of life saved per person were greater for children (1.0) than adults (0.5). With a 6% response rate, estimated costs per year of life saved for children ($5,700) were one-fourth of those of adults ($22,100). CONCLUSIONS: alpha-interferon therapy for patients with chronic active hepatitis B is cost effective. alpha-Interferon is more cost effective in toddlers than adults because of the smaller dose required and the greater increase in life expectancy of children.