Structures formed by human telomere sequence (HTS) DNA are of interest due to the implication of telomeres in the aging process and cancer. We present studies of HTS DNA folding in an anhydrous, high viscosity deep eutectic solvent (DES) comprised of choline choride and urea. In this solvent, the HTS DNA forms a G-quadruplex with the parallel-stranded ("propeller") fold, consistent with observations that reduced water activity favors the parallel fold, whereas alternative folds are favored at high water activity. Surprisingly, adoption of the parallel structure by HTS DNA in the DES, after thermal denaturation and quick cooling to room temperature, requires several months, as opposed to less than 2 min in an aqueous solution. This extended folding time in the DES is, in part, due to HTS DNA becoming kinetically trapped in a folded state that is apparently not accessed in lower viscosity solvents. A comparison of times required for the G-quadruplex to convert from its aqueous-preferred folded state to its parallel fold also reveals a dependence on solvent viscosity that is consistent with Kramers rate theory, which predicts that diffusion-controlled transitions will slow proportionally with solvent friction. These results provide an enhanced view of a G-quadruplex folding funnel and highlight the necessity to consider solvent viscosity in studies of G-quadruplex formation in vitro and in vivo. Additionally, the solvents and analyses presented here should prove valuable for understanding the folding of many other nucleic acids and potentially have applications in DNA-based nanotechnology where time-dependent structures are desired.
Background: Hyperhidrosis (HH) is a relatively common disorder involving excessive sweating, typically of the palms or axilla. HH can also frequently occur after limb amputation, where the remaining residual limb excessively perspires, leading to an increased risk of dermatological disorders and functional limitations, such as the inability to comfortably or safely wear a prosthesis. Although many treatments have been proposed to treat HH within the dermatology community, they are not widely known by healthcare providers typically involved in caring for individuals with acquired limb loss. Objectives: To appraise the current state of quantitative and qualitative assessment of HH within the residual limb and examine existing and future treatment strategies for this problem. Study design: Narrative Literature Review. Methods: A literature review focused on the assessment and treatment of excessive sweating of residual limbs. Results: There is currently no objective or subjective standard to assess or diagnose HH of the residual limb. Conventional therapies for HH do not always translate to the population of individuals with limb loss. Emerging modalities for treating HH show promise toward a permanent resolution of excess perspiration but require additional studies within people with amputation.Conclusions: Further research is needed to quantify standard values to objectively and subjectively assess and diagnose hyperhidrosis of the residual limb. New and developing treatments for hyperhidrosis require additional studies to assess efficacy and safety in the residual limb.
Selective endovascular embolization using microspheres is a widely used, relatively low‐risk procedure to control intracranial bleeding. Side effects such as cranial nerve palsies and stroke have been reported in the literature. Skin necrosis and alopecia are exceedingly rare complications of endovascular embolization with a reported incidence of less than 1%. We report a case of a 55‐year‐old female who developed alopecia following a therapeutic embolization of the middle meningeal artery using microspheres. The clinical‐histopathologic diagnosis and relevant literature are reviewed.
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