The importance of early recognition in management of ERCP-related perforations.

BACKGROUND: Iatrogenic perforations related to endoscopic retrograde cholangiopancreatography (ERCP) are rare events, carrying with it a mortality of up to 8%. Given the rarity of this adverse event, there remains limited data and continued uncertainties when choosing therapeutic strategies. Our aims were to evaluate the management of ERCP-related perforations and compare outcomes based on timing of recognition. METHODS: The endoscopic databases of two tertiary care centers were interrogated to identify consecutive adult patients who sustained ERCP-related perforation over a 10-year period from 2006 to 2016. Electronic medical records were reviewed to extract demographic data, perforation type, management strategies, clinical data, and patient outcomes. RESULTS: 14,045 ERCP's were performed during our 10-year study period. Sixty-three patients (average age 62.3 ± 2.38 years, 76% female) with ERCP-related perforations were included. Stapfer I perforations were found in 14 (22.2%) patients, Stapfer II in 24 (38.1%), and Stapfer III and IV perforations were identified in 16 (25.4%) and 9 (14.28%), respectively. Forty-seven (74.6%) perforations were recognized immediately during the ERCP, whereas 16 (25.4%) were recognized late. Endoscopic therapy was attempted in 35 patients in whom perforations were identified immediately, and was technically successful in 33 (94.3%). In all, 4 (1 immediate/ 3 delayed) patients required percutaneous drainage and 9 (5 immediate/ 4 delayed) surgery. Length of hospital stay, ICU admission were significantly shorter and incidence of SIRS was significantly lower when perforation was recognized immediately. CONCLUSIONS: Immediate recognition of ERCP-related perforations leads to more favorable patient outcomes; with lower incidence of SIRS, less need for ICU level care, and shorter hospital stay.

Quantitative Analysis of Supporting Cell Subtype Labeling Among CreER Lines in the Neonatal Mouse Cochlea.

Four CreER lines that are commonly used in the auditory field to label cochlear supporting cells (SCs) are expressed in multiple SC subtypes, with some lines also showing reporter expression in hair cells (HCs). We hypothesized that altering the tamoxifen dose would modify CreER expression and target subsets of SCs. We also used two different reporter lines, ROSA26 tdTomato and CAG-eGFP, to achieve the same goal. Our results confirm previous reports that Sox2 CreERT2 and Fgfr3-iCreER T2 are not only expressed in neonatal SCs but also in HCs. Decreasing the tamoxifen dose did not reduce HC expression for Sox2 CreERT2 , but changing to the CAG-eGFP reporter decreased reporter-positive HCs sevenfold. However, there was also a significant decrease in the number of reporter-positive SCs. In contrast, there was a large reduction in reporter-positive HCs in Fgfr3-iCreER T2 mice with the lowest tamoxifen dose tested yet only limited reduction in SC labeling. The targeting of reporter expression to inner phalangeal and border cells was increased when Plp-CreER T2 was paired with the CAG-eGFP reporter; however, the total number of labeled cells decreased. Changes to the tamoxifen dose or reporter line with Prox1 CreERT2 caused minimal changes. Our data demonstrate that modifications to the tamoxifen dose or the use of different reporter lines may be successful in narrowing the numbers and/or types of cells labeled, but each CreER line responded differently. When the ROSA26 tdTomato reporter was combined with any of the four CreER lines, there was no difference in the number of tdTomato-positive cells after one or two injections of tamoxifen given at birth. Thus, tamoxifen-mediated toxicity could be reduced by only giving one injection. While the CAG-eGFP reporter consistently labeled fewer cells, both reporter lines are valuable depending on the goal of the study.

Generation of Atoh1-rtTA transgenic mice: a tool for inducible gene expression in hair cells of the inner ear.

Atoh1 is a basic helix-loop-helix transcription factor that controls differentiation of hair cells (HCs) in the inner ear and its enhancer region has been used to create several HC-specific mouse lines. We generated a transgenic tetracycline-inducible mouse line (called Atoh1-rtTA) using the Atoh1 enhancer to drive expression of the reverse tetracycline transactivator (rtTA) protein and human placental alkaline phosphatase. Presence of the transgene was confirmed by alkaline phosphatase staining and rtTA activity was measured using two tetracycline operator (TetO) reporter alleles with doxycycline administered between postnatal days 0-3. This characterization of five founder lines demonstrated that Atoh1-rtTA is expressed in the majority of cochlear and utricular HCs. Although the tetracycline-inducible system is thought to produce transient changes in gene expression, reporter positive HCs were still observed at 6 weeks of age. To confirm that Atoh1-rtTA activity was specific to Atoh1-expressing cells, we also analyzed the cerebellum and found rtTA-driven reporter expression in cerebellar granule neuron precursor cells. The Atoh1-rtTA mouse line provides a powerful tool for the field and can be used in combination with other existing Cre recombinase mouse lines to manipulate expression of multiple genes at different times in the same animal.