Polyethylene glycol (PEG) is a synthetic biocompatible polymer with many useful properties for developing therapeutics to treat spinal cord injury. Direct application of PEG as a fusogen to the injury site can repair cell membranes, mitigate oxidative stress, and promote axonal regeneration to restore motor function. PEG can be covalently or noncovalently conjugated to proteins, peptides, and nanoparticles to limit their clearance by the reticuloendothelial system, reduce their immunogenicity, and facilitate crossing the blood–brain barrier. Cross-linking PEG produces hydrogels that can act as delivery vehicles for bioactive molecules including growth factors and cells such as bone marrow stromal cells, which can modulate the inflammatory response and support neural tissue regeneration. PEG hydrogels can be cross-linked in vitro or delivered as an injectable formulation that can gel in situ at the site of injury. Chemical and mechanical properties of PEG hydrogels are tunable and must be optimized for creating the most favorable delivery environment. Peptides mimicking extracellular matrix protein such as laminin and n-cadherin can be incorporated into PEG hydrogels to promote neural differentiation and axonal extensions. Different hydrogel cross-linking densities and stiffness will also affect the differentiation process. PEG hydrogels with a gradient of peptide concentrations or Young’s modulus have been developed to systematically study these factors. This review will describe these and other recent advancements of PEG in the field of spinal cord injury in greater detail.

Sonidegib, a hedgehog pathway inhibitor, was approved by the US FDA for the treatment of locally advanced basal cell carcinoma which cannot be readily treated with surgery or radiotherapy. The pharmacology and pharmacokinetics of sonidegib will be discussed in this review. Additionally, an in-depth analysis of the BOLT trial and data from the 30-month update will be included. This will serve as an update to a previously published article which reported the 12-month update of the BOLT trial. BackgroundBasal cell carcinoma (BCC) is the most common skin cancer in humans. Annually, there are 2.8 million cases that result in approximately 3000 deaths [1]. The use of surgical excision for the treatment of BCC results in a 5-year cure rate close to 90% [2,3]. The 5-year recurrence rate decreases to 0.7-2.4% when Mohs micrographic surgery (MMS) is performed [4][5][6][7]. Alternative nonsurgical approaches include cryotherapy, electrodesiccation and curettage, photodynamic therapy, radiation, or topical agents such as imiquimod or 5-fluorouracil. These options usually confer a lower cure rate and lack confirmation of tumor clearance on histology. Although metastasis of BCC has a very low incidence of 0.0028-0.

Erythema ab igne is an asymptomatic cutaneous disorder characterized by erythematous reticulated hyperpigmentation resulting from chronic exposure to infrared radiation in the form of heat. We report three cases of erythema ab igne from chronic heating pad use over a duration of six months to three years. The lesions were asymptomatic in all three patients and were incidental skin findings in two patients, unrelated to their chief complaints. This illustrates the importance of recognizing the morphology and distribution of erythema ab igne. Additionally, knowledge of similarly presenting cutaneous diseases is important to distinguish erythema ab igne from other more worrisome entities that would require further evaluation. Our patients were informed of the benign nature of this condition and were told that cessation of heating pad use would likely result in the resolution of their lesions.

Systemic therapies including PD-1 inhibitors and CTLA-4 inhibitors have demonstrated early promising results for difficult-to-treat NMSC. Future studies are necessary to optimize treatment outcome.

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