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AP endonuclease (AP endo), a key enzyme in repair of abasic sites in DNA, makes a single nick 5′ to the phosphodeoxyribose of an abasic site (AP-site). We recently proposed a novel mechanism, whereby the enzyme uses a key tyrosine (Tyr 171 ) to directly attack the scissile phosphate of the APsite. We showed that loss of the tyrosyl hydroxyl from Tyr 171 resulted in dramatic diminution in enzymatic efficiency. Here we extend the previous work to compare binding/recognition of AP endo to oligomeric DNA with and without an AP-site by wild type enzyme and several tyrosine mutants including Tyr 128 , Tyr 171 and Tyr 269 . We used single turnover and electrophoretic mobility shift assays. As expected, binding to DNA with an AP-site is more efficient than binding to DNA without one. Unlike catalytic cleavage by AP endo, which requires both hydroxyl and aromatic moieties of Tyr 171 , the ability to bind DNA efficiently without an AP-site is independent of an aromatic moiety at position 171. However, the ability to discriminate efficiently between DNA with and without an AP-site requires tyrosine at position 171. Thus, AP endo requires a tyrosine at the active site for the properties that enable it to behave as an efficient, processive endonuclease.

Since objective swallowing evaluation (eg, FEES) can be performed with an NG tube in place, it is not necessary to remove an NG tube to evaluate for aspiration. Similarly, there is no contraindication to leaving an NG tube in place to supplement oral alimentation until nutritional requirements are achieved.

Introduction: Brow-lift and upper blepharoplasty are often done sequentially to achieve adequate rejuvenation of the upper face. We describe the feasibility of a novel method of addressing both the aged forehead and upper eyelid fat pseudoherniation via an open brow-lift approach. Materials and Methods: We performed our technique on 6 cadaver and 3 human subjects. A brow-lift was performed in open fashion followed by upper eyelid fat excision through the superiorly exposed orbital septum. Position of the orbital fat from this approach and its ease of excision were recorded. Results: In all cases, the medial and central fat compartments were medial and lateral to the supraorbital nerve, respectively. Fat was accessible and amenable to excision from this approach. There were no complications related to this technique. Conclusions: When upper eyelid dermatochalasia is resolved when an open brow-lift is performed, this technique addresses upper eyelid fat pseudoherniation through the same brow-lift incision. Although this procedure is feasible and safe, long-term results in a greater number of patients are needed to confirm its role in aesthetic surgery.

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Introduction: Standard face-lift and blepharoplasty techniques historically have been of limited benefit in the midface, nasolabial folds, temporal periorbita, and orbital trough. Over the years, these challenging areas have been addressed with customized repositioning surgical maneuvers. The use of a new bioactive tissue matrix in conjunction with these maneuvers is a new approach to treating these challenging problems. Materials and Methods: Fifteen patients were treated with a combination of esthetic facial surgery and tissue regeneration matrix over 2 years by the senior author (J. H.). Preoperatively, all procedures were explained to the patients and written consent was obtained. During these procedures, the Biodesign tissue generation matrix was used to provide both supportive and volumetric expansion in a variety of areas of the face and neck for purposes of volumetric enhancement, neck suspension, and in one case for carotid artery coverage. The implant was soaked in sterile normal saline for no longer than 5 minutes to provide rehydration. The shape of the implant used was determined at the time of implantation based on the surgical need. Results: In total, 15 patients received the Biomatrix implantation in various areas. The results have been esthetically pleasing to both the surgeon and the patients, and complications have been minimal. While no attempt for quantitative volumetric analysis was made, this report provides photographic examples of the unique results that have been observed in surgical areas previously not well addressed with other techniques. Conclusions: By combining established methods of tissue lifting and reposition with strategic tissue replenishment and suspension, the benefits of facial surgery can be expanded beyond the prior limitations of surgery alone. The use of the biologic matrix to provide volumetric expansion in areas of volume loss due to aging is a robust, reliable, and safe adjunct to traditional cosmetic surgical procedures of the face.