Bedside upper gastrointestinal series in the neonatal intensive care unit.

BACKGROUND: In neonatal intensive care unit (NICU) patients with intubation status, fluoroscopic evaluation for the bowel is limited. This study was to evaluate the utility of bedside upper gastrointestinal (UGI) series with delayed radiographs (DR) for assessing duodenojejunal junction (DJJ) and small bowel passage in NICU patients with nonspecific bowel ultrasonography and contrast enema findings. METHODS: We reviewed clinical and imaging data for bedside UGI with DR of NICU patients from 2014 to 2019. Five abdominal radiographs were obtained at fixed time intervals of immediately after, 1 min, 5 min, 1 h, and 2 h following the administration of 5 cc/kg isotonic water-soluble contrast agent via the nasogastric tube. RESULTS: Twenty bedside UGI with DR were performed in 17 patients (weight range: 520-3620 g, age range: 0-4 months). Confidence identifying the DJJ was either good (n = 7) or equivocal (n = 8) at immediate or 1 min radiographs. The DJJ could not be evaluated in five from four delayed passage (including two meconium plug syndrome and one gastric volvulus) and one inadequate timing. There was only one case of intestinal malrotation, which was not detected on ultrasonography, but detected at the first UGI examination with good DJJ confidence. CONCLUSIONS: Bedside UGI with DR can evaluate intestinal malrotation using immediate and 1 min delay and small bowel passage using 1 and 2 h delay images in NICU patients with nonspecific ultrasonographic and contrast enema findings. The majority with delayed contrast passages can have bowel pathology. Because of a small number of patients in this study, further studies with more infants are needed.

The dynamics of long-term transgene expression in engrafted neural stem cells.

To assess the dynamics and confounding variables that influence transgene expression in neural stem cells (NSCs), we generated distinct NSC clones from the same pool of cells, carrying the same reporter gene transcribed from the same promoter, transduced by the same retroviral vector, and transplanted similarly at the same differentiation state, at the same time and location, into the brains of newborn mouse littermates, and monitored in parallel for over a year in vivo (without immunosuppression). Therefore, the sole variables were transgene chromosomal insertion site and copy number. We then adapted and optimized a technique that tests, at the single cell level, persistence of stem cell-mediated transgene expression in vivo based on correlating the presence of the transgene in a given NSC's nucleus (by fluorescence in situ hybridization [FISH]) with the frequency of that transgene's product within the same cell (by combined immunohistochemistry [IHC]). Under the above-stated conditions, insertion site is likely the most contributory variable dictating transgene downregulation in an NSC after 3 months in vivo. We also observed that this obstacle could be effectively and safely counteracted by simple serial infections (as few as three) inserting redundant copies of the transgene into the prospective donor NSC. (The preservation of normal growth control mechanisms and an absence of tumorigenic potential can be readily screened and ensured ex vivo prior to transplantation.) The combined FISH/IHC strategy employed here for monitoring the dynamics of transgene expression at the single cell level in vivo may be used for other types of therapeutic and housekeeping genes in endogenous and exogenous stem cells of many organs and lineages.