Infantile hypertrophic pyloric stenosis: are viruses involved?

Infantile hypertrophic pyloric stenosis (IHPS) is characterized by abnormal thickening of the internal circular muscle layer. IHPS is known to be due to a combination of genetic and environmental factors, but its precise causes and pathophysiology are poorly understood. The objective of the study is to determine the prevalence of the principal viruses targeting the respiratory and digestive tracts in children with IHPS. Nasopharyngeal fluids, stools, vomit, and surgical pyloric muscle fragments and swabs were tested by cell culture, viral antigen assay and PCR. IHPS was diagnosed in 23 boys and 8 girls with a mean (± SD) age of 42 ± 15 days (range 20-88 days). There was no seasonal pattern of diagnosis. Twenty-two children (71%) lost weight (mean 246 ± 164 g, range 30-600 g) after the onset of vomiting, and five (16.1%) were dehydrated. Seven (22.6%) infants had been exposed to an infectious contact within 15 days before admission, and one on the day of admission (3.2%). Ear, nose and throat samples and pyloric muscle specimens were negative for all the viruses tested. An adenovirus type 3 was recovered from one stool sample, and RT-PCR was positive for an enterovirus on one vomit sample. This study suggests that the principal viruses targeting the respiratory and digestive tracts are not responsible for IHPS.

Reference genes evaluated for use in infectious pancreatic necrosis virus real-time RT-qPCR assay applied during different stages of an infection.

The stability of 6 reference genes, 18S, beta-actin, RPS20, eEF1alpha, G6PDH and GAPDH, was examined in tissues from Atlantic salmon (Salmo salar) and Chinook salmon embryo cells (CHSE-214). The main objective of this study was to determine the most suitable reference genes for use for the normalisation of data in quantitative real-time RT-qPCR assays conducted on infected tissues. The tissue samples selected for analysis were taken from head kidney and pylorus and collected at different time points during a challenge experiment with infectious pancreatic necrosis virus (IPNV). The stability of some of the reference genes was also studied in infected CHSE-214 cells. The ranking of the genes examined was carried out using the geNorm program. This program determines the most stable genes from a set of genes tested in a given cDNA sample. The stability of the reference genes varied in different tissues and in the cell line at different stages of infection with IPNV. This study demonstrated that tissue-specific combinations of reference genes must be used to normalise real time data for use for the quantitation of IPNV.