A Case of Cutaneous Vasculitis in the Setting of Systemic Lupus Erythematosus and Cocaine Use.

Cocaine, one of most prevalent illicit substances in the United States, affects a multitude of organ systems and precedes numerous negative health outcomes. Many of the consequences of cocaine are linked to induction of vasoconstriction. For this reason, cocaine users are placed at considerable risk of ischemic stroke, myocardial infarction, and cardiac arrhythmias. Furthermore, a prominent contaminant, levamisole, has been widely implicated in predisposing individuals to developing or exacerbating cutaneous vasculitides. This report details a 31-year-old woman with acute, localized necrotic skin lesions after cocaine use. Her clinical picture was complicated by a 17-year history of systemic lupus erythematosus (SLE) and Raynaud's phenomenon. This case examines the challenge of forming a differential diagnosis, initiating an appropriate workup, and interpreting serologic-based and immunologic-based studies to differentiate between SLE and drug-based etiologies of skin necrosis. Finally, we discuss appropriate treatment plans to mitigate symptoms and reduce future instances of drug-induced vasculitis.

A novel role for trithorax in the gene regulatory network for a rapidly evolving fruit fly pigmentation trait.

Animal traits develop through the expression and action of numerous regulatory and realizator genes that comprise a gene regulatory network (GRN). For each GRN, its underlying patterns of gene expression are controlled by cis-regulatory elements (CREs) that bind activating and repressing transcription factors. These interactions drive cell-type and developmental stage-specific transcriptional activation or repression. Most GRNs remain incompletely mapped, and a major barrier to this daunting task is CRE identification. Here, we used an in silico method to identify predicted CREs (pCREs) that comprise the GRN which governs sex-specific pigmentation of Drosophila melanogaster. Through in vivo assays, we demonstrate that many pCREs activate expression in the correct cell-type and developmental stage. We employed genome editing to demonstrate that two CREs control the pupal abdomen expression of trithorax, whose function is required for the dimorphic phenotype. Surprisingly, trithorax had no detectable effect on this GRN's key trans-regulators, but shapes the sex-specific expression of two realizator genes. Comparison of sequences orthologous to these CREs supports an evolutionary scenario where these trithorax CREs predated the origin of the dimorphic trait. Collectively, this study demonstrates how in silico approaches can shed novel insights on the GRN basis for a trait's development and evolution.