Site‐specific transgenesis of the Drosophila melanogaster Y‐chromosome using CRISPR/Cas9

Despite the importance of Y‐chromosomes in evolution and sex determination, their heterochromatic, repeat‐rich nature makes them difficult to sequence (due, in part, to ambiguities in sequence alignment and assembly) and to genetically manipulate. Therefore, they generally remain poorly understood. For example, the Drosophila melanogaster Y‐chromosome, one of the most extensively studied Y‐chromosomes, is widely heterochromatic and composed mainly of highly repetitive sequences, with only a handful of expressed genes scattered throughout its length. Efforts to insert transgenes on this chromosome have thus far relied on either random insertion of transposons (sometimes harbouring ‘landing sites’ for subsequent integrations) with limited success or on chromosomal translocations, thereby limiting the types of Y‐chromosome‐related questions that could be explored. Here, we describe a versatile approach to site‐specifically insert transgenes on the Y‐chromosome in D. melanogaster via CRISPR/Cas9‐mediated homology‐directed repair. We demonstrate the ability to insert, and detect expression from, fluorescently marked transgenes at two specific locations on the Y‐chromosome, and we utilize these marked Y‐chromosomes to detect and quantify rare chromosomal nondisjunction effects. Finally, we discuss how this Y‐docking technique could be adapted to other insects to aid in the development of genetic control technologies for the management of insect disease vectors and pests.     

Diabetic ketoacidosis induced by a single dose of pembrolizumab

Immune checkpoint inhibitors are a new class of anticancer drugs recently approved by the US Food and Drug Administration (FDA) for the treatment of various malignancies. Pembrolizumab is an immune checkpoint inhibitor that targets the programmed cell death protein-1 (PD-1) receptor and blocks its interaction with programmed cell death ligand-1 (PD-L1) and programmed cell death ligand-2 (PD-L2). Pembrolizumab was first approved by the FDA in 2014 for the treatment of advanced melanoma and is currently approved for use in non-small cell lung cancer and several other neoplasms. Immune checkpoint inhibitors such as pembrolizumab have been reported to induce immune-mediated side effects, including type 1 diabetes mellitus in very rare cases (0.1% in clinical trials). Here, we report the case of a woman with no known history of diabetes who presented to our emergency department in a state of diabetic ketoacidosis within 3?weeks of receiving only a single dose of pembrolizumab therapy, and without any previous exposure to immunotherapy. This case of abrupt adult-onset type 1 diabetes mellitus is an example of the undesirable side effects that can emerge after only a brief exposure to an immune checkpoint inhibitor. Close monitoring of patients receiving immune checkpoint inhibitors is warranted for the early diagnosis and management of imminent and potentially life-threatening complications.     

Visual and refractive outcomes of 100 small incision lenticule extractions (SMILE) in moderate and high myopia: a 24-month follow-up study

Graefe's Archive for Clinical and Experimental Ophthalmology - We aimed to present the visual results obtained in 100 small incision lenticule extraction (SMILE) refractive surgeries,...