Molecular and genetic studies over the past two decades have established that animals ranging from the fruit fly to the human utilize a common "toolkit" of genes to create the myriad cell types during development. For even some of the most well studied developmental paradigms, however, little is known of the transcriptional regulatory networks activated by these core components. Moreover, how these networks manifest the initial cell fate decision remains a rigorous topic of investigation. The Drosophila melanogaster mechanosensory organ lineage has long been a model for binary cell fate specification mechanisms. While it is well-established that the Notch signaling pathway is the dominant cell fate specification mechanism in this lineage, little is known of the battery of genes downstream of the canonical pathway components that enforce the cell fate decision. In this body of work I analyze the Notch signaling events at opposite ends of the lineage with the specification of the mechanosensory organ precursor cell (SOP) at the beginning and the post-mitotic socket and shaft cells at the penultimate of the lineage. These studies focus on the transcriptional regulation of three genes, neuralized, Sox15 and sv. I utilize a number of loss of function mutants, misexpression studies, and transgenic reporter constructs to identify enhancer modules and tease out their regulatory factors. Chapter 2 comprises an analysis of the transcriptional regulation of neuralized during SOP specification where I present evidence that neuralized is both a participant in and a target of Notch signaling, requiring two partially redundant. Chapter 3 focuses on the transcriptional regulation and function of Sox15, a transcription factor specifically expressed in the post-mitotic socket cell. I show that Sox15 is a target of Notch signaling in the socket cell and is required for the proper differentiation of the socket cell as it relates to mechanosensory function. Chapter 4 dovetails off Sox15 and examines regulation of sv in the shaft cell, where I find the dominant theme is auto-regulation. Lastly, Chapter 5 describes the development of a new transgenic reporter system I developed for the rapid screening of genomic fragments for enhancer activity.

Clinical metagenomic next-generation sequencing (mNGS), the comprehensive analysis of microbial and host genetic material (DNA and RNA) in samples from patients, is rapidly moving from research to clinical laboratories. This emerging approach is changing how physicians diagnose and treat infectious disease, with applications spanning a wide range of areas, including antimicrobial resistance, the microbiome, human host gene expression (transcriptomics) and oncology. Here, we focus on the challenges of implementing mNGS in the clinical laboratory and address potential solutions for maximizing its impact on patient care and public health.

Most clinicians would agree that there is no reason to obtain a magnetic resonance (MR) scan to evaluate a patient with viral conjunctivitis. We scheduled a patient for an annual MR scan to monitor his optic nerve meningiomas. By coincidence, he had florid viral conjunctivitis the day the scan was performed. It showed severe eyelid edema, contrast enhancement of the anterior orbit, enlargement of the lacrimal gland, and obstruction of the nasolacrimal duct. Adenovirus produces deep orbital inflammation, in addition to infection of the conjunctival surface.

Developmental patterning involves the progressive subdivision of tissue into different cell types by invoking different genetic programs. In particular, cell-cell signaling is a universally deployed means of specifying distinct cell fates in adjacent cells. For this mechanism to be effective, it is essential that an asymmetry be established in the signaling and responding capacities of the participating cells. Here we focus on the regulatory mechanisms underlying the role of the neuralized gene and its protein product in establishing and maintaining asymmetry of signaling through the Notch pathway. The context is the classical process of "lateral inhibition" within Drosophila proneural clusters, which is responsible for distinguishing the sensory organ precursor (SOP) and non-SOP fates among adjacent cells. We find that neur is directly regulated in proneural clusters by both proneural transcriptional activators and Enhancer of split basic helix-loop-helix repressors (bHLH-Rs), via two separate cis-regulatory modules within the neur locus. We show that this bHLH-R regulation is required to prevent the early, pre-SOP expression of neur from being maintained in a subset of non-SOPs following SOP specification. Lastly, we demonstrate that Neur activity in the SOP is required to inhibit, in a cell non-autonomous manner, both neur expression and Neur function in non-SOPs, thus helping to secure the robust establishment of distinct cell identities within the developing proneural cluster.

Most great powers had internationalized coalitions in 1914, but some were stronger than others. In particular the German internationalizers faced heavy industry, militarists, and apostles of Weltpolitik to say nothing of the military itself. Mercantilists were also opposed. China’s internationalizers are far stronger than those in Germany in 1914.

Background

Characterization of brain injury and neurodevelopmental (ND) outcomes in critical congenital heart disease (cCHD) has primarily focused on hypoplastic left heart syndrome (HLHS) and transposition of the great arteries (TGA). This study reports brain injury and ND outcomes among patients with heterogeneous cCHD diagnoses beyond HLHS and TGA.

Methods

This prospective cohort study included infants with HLHS, TGA, or heterogenous "Other cCHD" including left- or right-sided obstructive lesions, anomalous pulmonary venous return, and truncus arteriosus. Brain injury on perioperative brain MRI and ND outcomes on the Bayley-II at 30 months were compared.

Results

A total of 218 participants were included (HLHS = 60; TGA = 118; "Other cCHD" = 40, including 8 with genetic syndromes). Pre-operative (n = 209) and post-operative (n = 189) MRI showed similarly high brain injury rates across groups, regardless of cardiopulmonary bypass exposure. At 30 months, participants with "Other cCHD" had lower cognitive scores (p = 0.035) compared to those with HLHS and TGA, though worse ND outcome in this group was driven by those with genetic disorders.

Conclusions

Frequency of brain injury and neurodevelopmental delay among patients with "Other cCHD" is similar to those with HLHS or TGA. Patients with all cCHD lesions are at risk for impaired outcomes; developmental and genetic screening is indicated.

Impact

This study adds to literature on risk of brain injury in patients with critical congenital heart disease (cCHD) diagnoses other than hypoplastic left heart syndrome (HLHS) and transposition of the great arteries (TGA), a heterogenous cohort of patients that has often been excluded from imaging studies. Children with cCHD beyond HLHS and TGA have similarly high rates of acquired brain injury. The high rate of neurodevelopmental impairment in this heterogenous group of cCHD diagnoses beyond HLHS and TGA is primarily driven by patients with comorbid genetic syndromes such as 22q11.2 deletion syndrome.