We investigate by X-ray crystallographic techniques the cryotrapped states that accumulate on controlled illumination of the blue light photoreceptor, photoactive yellow protein (PYP), at 110 K in both the wild-type species and its E46Q mutant. These states are related to those that occur during the chromophore isomerization process in the PYP photocycle at room temperature. The structures present in such states were determined at high resolution, 0.95-1.05. In both wild type and mutant PYP, the cryotrapped state is not composed of a single, quasitransition state structure but rather of a heterogeneous mixture of three species in addition to the ground state structure. We identify and refine these three photoactivated species under the assumption that the structural changes are limited to simple isomerization events of the chromophore that otherwise retains chemical bonding similar to that in the ground state. The refined chromophore models are essentially identical in the wild type and the E46Q mutant, which implies that the early stages of their photocycle mechanisms are the same.

Background: Targeted muscle reinnervation (TMR) has been shown to decrease or prevent neuropathic pain, including phantom and residual limb pain, after extremity amputation. Currently, a paucity of data and lack of anatomical description exists regarding TMR in the setting of hemipelvectomy and/or hip disarticulations. We elaborate on the technique of TMR, illustrated through cadaveric and clinical correlates. Methods: Cadaveric dissections of multiple transpelvic exposures were performed. The major mixed motor and sensory nerve branches were identified, dissected, and tagged. Amputated peripheral nerves were transferred to identified, labeled target motor nerves via direct end-to-end nerve coaptations per traditional TMR technique. A retrospective review was completed by our multi-institutional teams to include examples of clinical correlates for TMR performed in the setting of hemipelvectomies and hip disarticulations. Results: A total of 12 TMR hemipelvectomy/hip disarticulation cases were performed over a 2 to 3-year period (2018-2020). Of these 12 cases, 9 were oncologic in nature, 2 were secondary to traumatic injury, and 1 was a failed limb salvage in the setting of chronic refractory osteomyelitis of the femoral shaft. Conclusions: This manuscript outlines the technical considerations for TMR in the setting of hemipelvectomy and hip disarticulation with supporting clinical case correlates.

Management of head and neck defects in a radiated field can be quite challenging owing to the dearth of vasculature and significant degree of post-radiation fibrosis. In this setting, arteriovenous (AV) loop vascular grafts can bypass nonviable local vessels to provide viable and reliable inflow and outflow vessels for free tissue transfer in an otherwise hostile environment. Prior reports of the Corlett loop utilizing a cephalic vein transposition has been described however a common carotid-to-internal jugular AV loop has not been recently reported. Three patients underwent carotid artery to internal jugular vein AV loop creation to facilitate free-flap reconstruction secondary to radiation-induced vessel depletion. The specific technique described utilizes the saphenous vein as a donor and spares the cephalic vein for the possibility of flap complication. All three cases resulted in successful reconstruction, maintaining healthy tissue, vascular flow, and flap viability at all follow-up intervals. In our experience, vascular augmentation via AV loop formation provides reliable vascular inflow and outflow in the vessel-depleted neck to facilitate microvascular reconstruction. Sparing the cephalic vein yields an additional salvage mechanism in the event of venous congestion.

Complete congenital arhinia is a rare defect of embryogenesis leading to the absence of the external nose and airway. We report our novel multistaged reconstructive approach and literature review. Nasal methyl methacrylate prosthesis was created from a stereolithographic model for use as a temporary prosthesis and tissue expander. Lefort 1 with cannulization was utilized for midface advancement and airway formation. External framework was reconstructed with bilateral conchal bowl cartilage and rib osteocartilagenous grafts. Patient was pleased with the aesthetics and had safe decannulation with the ability to breathe through the nose and airway.

Purpose Despite changes in legislation and an increase in public awareness, many women may not have access to the various types of breast reconstruction. The purpose of this study was to evaluate variation in reconstructive modality at the health service area (HSA) level and its relationship to the plastic surgeon workforce in the same area. Methods Using the Arkansas, California, Florida, Nebraska, and New York state inpatient databases, we conducted a cross-sectional study of adult women undergoing mastectomy for cancer from 2009 to 2012. The primary outcomes were receipt of reconstruction and the reconstructive modality (autologous tissue versus implant) used. All data were aggregated to the HSA level and augmented with plastic surgeon workforce data. Correlation coefficients were calculated for the relationship between the outcomes and workforce. Results The final sample included 67,984 women treated across 103 HSAs. The average patient was 58.5 years, had private insurance (53.5%), and underwent unilateral mastectomy for invasive cancer. At the HSA level, the median immediate breast reconstruction rate was 25.0% and varied widely (interquartile range, 43.2%). In areas where reconstruction was performed, the median autologous (10.2%) and free tissue (0.4%) reconstruction rates were low, with more than 30% of HSAs never using autologous tissue. There was a direct correlation between an HSA's plastic surgeon density and autologous reconstruction rate (r = 0.81, P < 0.001). Conclusions Despite efforts to remove financial barriers and improve patients' awareness, accessibility to various modalities of reconstruction is inadequate for many women. Efforts are needed to improve the availability of more comprehensive breast reconstruction care.