Hematopoietic and neural crest defects in zebrafish shoc2 mutants: a novel vertebrate model for Noonan-like syndrome.

The extracellular signal-related kinase 1 and 2 (ERK1/2) pathway is a highly conserved signaling cascade with numerous essential functions in development. The scaffold protein Shoc2 amplifies the activity of the ERK1/2 pathway and is an essential modulator of a variety of signaling inputs. Germline mutations in Shoc2 are associated with the human developmental disease known as the Noonan-like syndrome with loose anagen hair. Clinical manifestations of this disease include congenital heart defects, developmental delays, distinctive facial abnormalities, reduced growth and cognitive deficits along with hair anomalies. The many molecular details of pathogenesis of the Noonan-like syndrome and related developmental disorders, cumulatively called RASopathies, remain poorly understood. Mouse knockouts for Shoc2 are embryonic lethal, emphasizing the need for additional animal models to study the role of Shoc2 in embryonic development. Here, we characterize a zebrafish shoc2 mutant, and show that Shoc2 is essential for development, and that its loss is detrimental for the development of the neural crest and for hematopoiesis. The zebrafish model of the Noonan-like syndrome described here provides a novel system for the study of structure-function analyses and for genetic screens in a tractable vertebrate system.

Insulinoma-associated 1a (Insm1a) is required for photoreceptor differentiation in the zebrafish retina.

The zinc-finger transcription factor insulinoma-associated 1 (Insm1, previously IA-1) is expressed in the developing nervous and neuroendocrine systems, and is required for cell type specific differentiation. Expression of Insm1 is largely absent in the adult, although it is present in neurogenic regions of the adult brain and zebrafish retina. While expression of Insm1 has also been observed in the embryonic retina of numerous vertebrate species, its function during retinal development has remained unexplored. Here, we demonstrate that in the developing zebrafish retina, insm1a is required for photoreceptor differentiation. Insm1a-deficient embryos were microphthalmic and displayed defects in rod and cone photoreceptor differentiation. Rod photoreceptor cells were more sensitive to loss of insm1a expression than were cone photoreceptor cells. Additionally, we provide evidence that insm1a regulates cell cycle progression of retinoblasts, and functions upstream of the bHLH transcription factors ath5/atoh7 and neurod, and the photoreceptor specification genes crx and nr2e3. Finally, we show that insm1a is negatively regulated by Notch-Delta signaling. Taken together, our data demonstrate that Insm1 influences neuronal subtype differentiation during retinal development.

Characterization of Admission Medication Reconciliations Performed by Pharmacists in a Pediatric Institution: Resource Allocation.

BACKGROUND: Compared with adults, children may be at greater risk of medication errors and potential adverse effects. The American Academy of Pediatrics recommends developing mechanisms for proactively identifying patients at risk for medication-related adverse events and failed reconciliation. This study's primary purpose was to evaluate pediatric patients admitted to identify risk factors requiring pharmacist intervention during medication reconciliation (MedRec). METHODS: This prospective study included pediatric patients admitted during the study time frame until the target population of 500 patient encounters was achieved. During each admission, pharmacy staff completed a medication history, after which a pediatric pharmacist completed a MedRec, as is standard hospital practice. The primary outcome was identification of factors for high-risk transitions of care during pediatric admissions based on the need for pharmacist interventions during the MedRec process. RESULTS: In total, 331 interventions were made for 127 patients (median 2; range, 1-12). Of the 331 interventions, 196 (59.2%) were classified as being of moderate or significant severity. Although patients with at least 2 home medications were significantly more likely to require any intervention (p < 0.0001), patients with 5 or more home medications were more likely to have a significant intervention. CONCLUSION: Identifying patients with home medications could allow for focused efforts to intervene. Also, patients admitted to the PICU or those with cardiology- or endocrinology-related diagnoses should be prioritized for MedRec process, because of the likelihood of requiring multiple home medications. This strategy should be tailored to individual pediatric institutions based on internal quality control assessments and available resources.

Microarray analysis of XOPS-mCFP zebrafish retina identifies genes associated with rod photoreceptor degeneration and regeneration.

PURPOSE: XOPS-mCFP transgenic zebrafish experience a continual cycle of rod photoreceptor development and degeneration throughout life, making them a useful model for investigating the molecular determinants of rod photoreceptor regeneration. The purpose of this study was to compare the gene expression profiles of wild-type and XOPS-mCFP retinas and identify genes that may contribute to the regeneration of the rods. METHODS: Adult wild-type and XOPS-mCFP retinal mRNA was subjected to microarray analysis. Pathway analysis was used to identify biologically relevant processes that were significantly represented in the dataset. Expression changes were verified by RT-PCR. Selected genes were further examined during retinal development and in adult retinas by in situ hybridization and immunohistochemistry and in a transgenic fluorescent reporter line. RESULTS: More than 600 genes displayed significant expression changes in XOPS-mCFP retinas compared with expression in wild-type controls. Many of the downregulated genes were associated with phototransduction, whereas upregulated genes were associated with several biological functions, including cell cycle, DNA replication and repair, and cell development and death. RT-PCR analysis of a subset of these genes confirmed the microarray RESULTS: Three transcription factors (sox11b, insm1a, and c-myb), displaying increased expression in XOPS-mCFP retinas, were also expressed throughout retinal development and in the persistently neurogenic ciliary marginal zone. CONCLUSIONS: This study identified numerous gene expression changes in response to rod degeneration in zebrafish and further suggests a role for the transcriptional regulators sox11b, insm1a, and c-myb in both retinal development and rod photoreceptor regeneration.