The rule of 10s versus the rule of 2s: High complication rates after conventional excision with postoperative margin assessment of specialty site versus trunk and proximal extremity melanomas.

Specialty site melanomas on the head and neck, hands and feet, genitalia, and pretibial leg have higher rates of surgical complications after conventional excision with postoperative margin assessment (CE-POMA) compared with trunk and proximal extremity melanomas. The rule of 10s describes complication rates after CE-POMA of specialty site melanomas: ∼10% risk for upstaging, ∼10% risk for positive excision margins, ∼10% risk for local recurrence, and ∼10-fold increased likelihood of reconstruction with a flap or graft. Trunk and proximal extremity melanomas encounter these complications at a lower rate, according to the rule of 2s. Mohs micrographic surgery (MMS) with frozen section melanocytic immunostains (MMS-I) and slow Mohs with paraffin sections decrease complications of surgery of specialty site melanomas by detecting upstaging and confirming complete tumor removal with comprehensive microscopic margin assessment before reconstruction. This article reviews information important for counseling melanoma patients about surgical treatment options and for developing consensus guidelines with clear indications for MMS-I or slow Mohs.

Melanomas of the head and neck have high-local recurrence risk features and require tissue-rearranging reconstruction more commonly than basal cell carcinoma and squamous cell carcinoma: A comparison of indications for microscopic margin control prior to reconstruction in 13,664 tumors.

BACKGROUND: On the basis of high-local recurrence risk features and tissue-rearranging reconstruction, consensus guidelines recommend microscopic margin control for keratinocyte carcinomas (KCs) but not for cutaneous melanoma. OBJECTIVE: To compare high-local recurrence risk features and frequency of tissue-rearranging reconstruction for head and neck KC with those for melanoma. METHODS: Retrospective cohort study of KC versus melanoma treated at the Hospital of the University of Pennsylvania with Mohs micrographic surgery. RESULTS: A total of 12,189 KCs (8743 basal cell carcinomas and 3343 squamous cell carcinomas) and 1475 melanomas (1065 melanomas in situ and 410 invasive melanomas) were identified from a prospectively updated Mohs micrographic surgery database. Compared with KCs, melanomas were significantly more likely to have high-local recurrence risk features, including larger preoperative size (2.10 cm vs 1.30 cm [P < .0001]), recurrent status (5.08% vs 3.91% [P = .031]), and subclinical spread (31.73% vs 26.52% [P < .0001]). Tissue-rearranging reconstruction was significantly more common for melanoma than for KCs (44.68% vs 33.02% [P < .0001]; odds ratio, 1.98 [P < .0001]). LIMITATIONS: This was a retrospective study, and it did not compare outcomes with those of other treatment methods, such as slow Mohs or conventional excision. CONCLUSION: Melanomas of the head and neck have high-local recurrence risk features and require tissue-rearranging reconstruction more frequently than KCs do.

Dining On Call: Outcomes of a hospital patient dining model.

Dining On Call (DOC) is a hospital foodservice model allowing patients to order meals any time throughout the day and is delivered within 45 minutes of the order. It is positively correlated with patient satisfaction, improvements in malnutrition, and reducing costs. Pre- and post-DOC data were collected from BC Children's Hospital, BC Women's Hospital, and North York General Hospital (NYGH) using patient satisfaction surveys and tray waste audits to measure outcomes. Patient satisfaction scores increased at all hospitals. BC Children's and Women's hospitals demonstrated reductions in tray waste, food cost/meal/day, and labour cost/meal/day post-DOC. North York General Hospital observed decreases in tray waste; however, food cost/meal/day and labour cost/meal/day increased post-DOC. This research provides convincing evidence into the achievable benefits associated with DOC on mother and paediatric units in hospital settings. DOC may prove to be an effective dining model for hospitals seeking to improve patient outcomes and reduce overall costs.

Variation in Prescribing and Factors Associated With the Use of Prophylactic Antibiotics for Mohs Surgery: A Single-Institution Retrospective Study.

BACKGROUND: Antibiotic use associated with Mohs surgery is increasing. OBJECTIVE: To understand variation in practice patterns and factors associated with antibiotic use. MATERIALS AND METHODS: The authors conducted a retrospective cohort study of antibiotic use among patients treated with Mohs micrographic surgery between July 1, 2013, and June 30, 2017, at an academic medical center. Multivariate logistic regression was used to evaluate for associations between antibiotic prescribing and the surgeon, site, reconstruction, and patient characteristics. RESULTS: The odds of prescribing antibiotics differed significantly between each surgeon evaluated; 3.35-fold variation in postoperative antibiotic use was observed. Increasing number of surgical sites (odds ratio [OR] 1.24; 95% confidence interval [CI] 1.09-1.41), number of Mohs stages required (OR 1.18; 95% CI 1.08-1.28), and defect area (OR 1.31; 95% CI 1.25-1.37), as well as patient female sex (OR 1.14; 95% CI 1.03-1.27), were associated with increased postoperative antibiotic use, whereas age >80 was associated with decreased use (OR 0.75; 95% CI 0.64-0.87) compared with age <60. CONCLUSION: Antibiotics are more commonly prescribed for repairs that are considered higher risk for infection. However, significant variation exists between surgeons, even within a single institution, suggesting a need for prospective trials and consensus guideline development.

Crescentic Modification to Island Pedicle Rotation Flaps for Defects of the Distal Nose.

BACKGROUND: Island pedicle flaps based on a lateral sling of the nasalis have difficulty reaching distal nasal defects due to tethering of the muscle to its insertion point. The authors hypothesized that reach could be improved by modifying a crescentic flap to rotate around a pivot point equidistant to the flap and the defect. OBJECTIVE: To describe the design, execution, and results with a modified crescentic island pedicle rotation flap for repair of distal nasal defects after Mohs micrographic surgery. METHODS: The authors performed a retrospective analysis of patients who had distal nasal defects repaired with a modified crescentic island pedicle rotation flap over an 8-year period. All charts and photographs were examined. Sex and age of the patient, type of cutaneous carcinoma, location and size of the defect, and complications were recorded. RESULTS: Forty-eight patients were included. The flap was used to successfully reconstruct defects on the distal nose ranging in size from 0.25 cm to 3.8 cm. Complications involved one wound infection and one episode of postoperative bleeding. CONCLUSION: The authors' modifications to the island pedicle flap may be reliably used to reconstruct small- to medium-sized defects of the distal nose in a single stage with minimal risk of complications.

Membrane (and Soluble) Protein Stability and Binding Measurements in the Lipid Cubic Phase Using Label-Free Differential Scanning Fluorimetry.

Label-free differential scanning fluorimetry (DSF) is a relatively new method for evaluating the stability of proteins. It can be used as a screening tool for downstream applications such as crystallization. The method is attractive in that it requires miniscule quantities of proteins, it can be performed using intrinsic tryptophan and tyrosine fluorescence, and, with the right equipment, it is easy to perform. To date, the method has been used with proteins in liquid solutions and dispersions. It was of interest to determine if DSF could be used with membrane proteins in the lipid cubic phase (LCP), which increasingly is being used for crystallization in support of structure-function studies. The cubic phase is viscous. Furthermore, in coexistence with excess aqueous solution, as happens during crystallization trials, it can become turbid and scatter light. The concern was that these features may render the mesophase unsuitable for DSF analysis. However, using lysozyme and four integral membrane proteins we demonstrate that the method works with all tested proteins in solution and in the LCP. Of note is the observation that some of the test membrane proteins are more stable while others are less so in the mesophase. The method also works in ligand binding measurements. Thus, DSF should prove useful as an analytical tool for identifying host and additive lipids, detergents, precipitants and chemical probes that support the generation of quality crystals by the cubic phase method. Microscale thermophoresis was used to supplement the DSF study and was also shown to work with proteins in the mesophase. Measurements with lysozyme highlight the utility of the cubic mesophase as a model system in which to perform confinement studies.

Fast native-SAD phasing for routine macromolecular structure determination.

We describe a data collection method that uses a single crystal to solve X-ray structures by native SAD (single-wavelength anomalous diffraction). We solved the structures of 11 real-life examples, including a human membrane protein, a protein-DNA complex and a 266-kDa multiprotein-ligand complex, using this method. The data collection strategy is suitable for routine structure determination and can be implemented at most macromolecular crystallography synchrotron beamlines.

Crystal structure and biochemical characterization of the transmembrane PAP2 type phosphatidylglycerol phosphate phosphatase from Bacillus subtilis.

Type 2 phosphatidic acid phosphatases (PAP2s) can be either soluble or integral membrane enzymes. In bacteria, integral membrane PAP2s play major roles in the metabolisms of glycerophospholipids, undecaprenyl-phosphate (C55-P) lipid carrier and lipopolysaccharides. By in vivo functional experiments and biochemical characterization we show that the membrane PAP2 coded by the Bacillus subtilis yodM gene is the principal phosphatidylglycerol phosphate (PGP) phosphatase of B. subtilis. We also confirm that this enzyme, renamed bsPgpB, has a weaker activity on C55-PP. Moreover, we solved the crystal structure of bsPgpB at 2.25 Å resolution, with tungstate (a phosphate analog) in the active site. The structure reveals two lipid chains in the active site vicinity, allowing for PGP substrate modeling and molecular dynamic simulation. Site-directed mutagenesis confirmed the residues important for substrate specificity, providing a basis for predicting the lipids preferentially dephosphorylated by membrane PAP2s.

Comparing the efficacies of alginate, foam, hydrocolloid, hydrofiber, and hydrogel dressings in the management of diabetic foot ulcers and venous leg ulcers: a systematic review and meta-analysis examining how to dress for success.

Diabetic foot ulcers and venous leg ulcers are chronic wounds frequently encountered by dermatologists. Choosing appropriate wound dressings can effectively promote wound healing and potentially reduce morbidity and financial burden experienced by patients. The objective of our systematic review and meta-analysis was to evaluate wound healing efficacies of synthetic active dressings in diabetic foot ulcer and venous leg ulcer management. For data collection, PubMed, Embase, Cochrane Library, CINAHL, and clinicaltrials.gov online databases were searched from database inception to 10 May 2015. Fixed and random effects modeling were used to calculate pooled risk ratios for complete ulcer healing from pairwise dressing comparisons. The results of our review showed moderate-quality level evidence that hydrogels were more effective in healing diabetic foot ulcers than basic wound contact dressings (RR 1.80 [95% CI, 1.27-2.56]). The other dressing comparisons showed no statistically significant differences between the interventions examined in terms of achieving complete diabetic foot ulcer healing. Non-adherent dressings were more cost-effective than hydrofiber dressings for diabetic foot ulcers in terms of mean total cost per patient of the dressings themselves. All venous leg ulcer pairwise dressing comparisons showed equivalent dressing efficacies in terms of promoting complete ulcer healing. Overall, most synthetic active dressings and traditional wound dressings are equally efficacious in treating diabetic foot ulcers and venous leg ulcers. For treating diabetic foot ulcers, hydrogels are more efficacious than basic wound contact dressings, and non-adherent dressings are more cost-effective than hydrofiber dressings. Ultimately, dressing choice should be tailored to the wound and the patient.

Adenoid cystic carcinoma of the base of the tongue metastasizing to the scalp.

Adenoid cystic carcinoma is a rare neoplasm that originates from secretory glands, most commonly from the salivary glands. We present a 76 year-old white man with a history of adenoid cystic carcinoma from the base of the tongue diagnosed 15 years prior to the development of the metastatic lesion on his mid-posterior scalp. The present case represents the second reported instance of an extracutaneous adenoid cystic carcinoma metastasizing to the scalp. Differentiating between a primary cutaneous adenoid cystic carcinoma and an extracutaneous adenoid cystic carcinoma metastasizing to cutaneous structures is crucial in determining prognosis and management.

Mechanism of the binding of Z-L-tryptophan and Z-L-phenylalanine to thermolysin and stromelysin-1 in aqueous solutions.

The chemical shift of the carboxylate carbon of Z-tryptophan is increased from 179.85 to 182.82 ppm and 182.87 ppm on binding to thermolysin and stromelysin-1 respectively. The chemical shift of Z-phenylalanine is also increased from 179.5 ppm to 182.9 ppm on binding to thermolysin. From pH studies we conclude that the pK(a) of the inhibitor carboxylate group is lowered by at least 1.5 pK(a) units when it binds to either enzyme. The signal at ~183 ppm is no longer observed when the active site zinc atom of thermolysin or stromelysin-1 is replaced by cobalt. We estimate that the distance of the carboxylate carbon of Z-[1-(13)C]-L-tryptophan is ≤3.71Å from the active site cobalt atom of thermolysin. We conclude that the side chain of Z-[1-(13)C]-L-tryptophan is not bound in the S(2)' subsite of thermolysin. As the chemical shifts of the carboxylate carbons of the bound inhibitors are all ~183 ppm we conclude that they are all bound in a similar way most probably with the inhibitor carboxylate group directly coordinated to the active site zinc atom. Our spectrophotometric results confirm that the active site zinc atom is tetrahedrally coordinated when the inhibitors Z-tryptophan or Z-phenylalanine are bound to thermolysin.

Obtaining rapid and effective hemostasis: Part I. Update and review of topical hemostatic agents.

Effective and rapid hemostasis is critical to optimize surgical outcomes. An advantageous adjunct in accelerating the clotting process during dermatologic surgery is the use of topical hemostatic agents, which allow dermatologic surgeons to quickly clear the surgical field while avoiding the adverse effects of systemic medications. The growing rate of patients with pacemakers and defibrillators limits the possibility of electrosurgery. It is not unusual for patients to be taking ≥1 anticoagulant medication(s). For these reasons, the use of topical hemostatic agents is likely to gain more recognition in the literature. The term topical hemostatic agents encompasses an array of pharmacotherapies, sealants, adhesives, absorbable agents, biologics, and combination products. The optimal use of topical hemostatic agents demands that dermatologic surgeons be familiar with each of these options, because the type of product used must be selected based on surgical location, wound size, and the extent of bleeding. With few randomized controlled trials in existence reviewing the efficacy of these medications, the subject of topical styptic agents has largely gone unstudied. Part I of this continuing medical education article reviews the available topical hemostatic agents and the ideal clinical settings for their use.

Obtaining rapid and effective hemostasis: Part II. Electrosurgery in patients with implantable cardiac devices.

Electrosurgery is an integral part of dermatology that is commonly used both to obtain hemostasis and to treat cutaneous lesions. However, it can cause many complications in patients with implantable devices. Because of the risk of electromagnetic interference, a variety of precautions are commonly used. Not only are there no consistent community-based standards in place regarding the performance of electrosurgery in patients with implantable devices, but these precautions are largely based upon anecdotal experience or recommendations from different specialties. To further complicate matters, the literature regarding electrosurgery use in patients with implantable cardiac devices is limited, especially with respect to dermatologic surgery. As the use of implantable cardiac devices continues to grow, our ability to care for patients with implantable devices must expand. Part II of this continuing medical education article discusses the current recommendations for using electrosurgery in patients with implantable cardiac devices during dermatologic procedures.

Importance of tetrahedral intermediate formation in the catalytic mechanism of the serine proteases chymotrypsin and subtilisin.

Two new inhibitors in which the terminal α-carboxyl groups of Z-Ala-Ala-Phe-COOH and Z-Ala-Pro-Phe-COOH have been replaced with a proton to give Z-Ala-Ala-Phe-H and Z-Ala-Pro-Phe-H, respectively, have been synthesized. Using these inhibitors, we estimate that for α-chymotrypsin and subtilisin Carlsberg the terminal carboxylate group decreases the level of inhibitor binding 3-4-fold while a glyoxal group increases the level of binding by 500-2000-fold. We show that at pH 7.2 the effective molarities of the catalytic hydroxyl group of the active site serine are 41000-229000 and 101000-159000 for α-chymotrypsin and subtilisin Carlsberg, respectively. It is estimated that oxyanion stabilization and the increased effective molarity of the catalytic serine hydroxyl group can account for the catalytic efficiency of the reaction. We argue that substrate binding induces the formation of a strong hydrogen bond or low-barrier hydrogen bond between histidine-57 and aspartate-102 that increases the pK(a) of the active site histidine, allowing it to be an effective general base catalyst for the formation of the tetrahedral intermediate and increasing the effective molarity of the catalytic hydroxyl group of serine-195. A catalytic mechanism for acyl intermediate formation in the serine proteases is proposed.

pH stability of the stromelysin-1 catalytic domain and its mechanism of interaction with a glyoxal inhibitor.

The stromelysin-1 catalytic domain(83-247) (SCD) is stable for at least 16 h at pHs 6.0-8.4. At pHs 5.0 and 9.0 there is exponential irreversible denaturation with half lives of 38 and 68 min respectively. At pHs 4.5 and 10.0 irreversible denaturation is biphasic. At 25°C, C-terminal truncation of stromelysin-1 decreases the stability of the stromelysin-1 catalytic domain at pH values >8.4 and <6.0. We describe the conversion of the carboxylate group of (ßR)-ß-[[[(1S)-1-[[[(1S)-2-Methoxy-1-phenylethyl]amino]carbonyl]-2,2-dimethylpropyl]amino]carbonyl]-2-methyl-[1,1'-biphenyl]-4-hexanoic acid (UK-370106-COOH) a potent inhibitor of the metalloprotease stromelysin-1 to a glyoxal group (UK-370106-CO(13)CHO). At pH 5.5-6.5 the glyoxal inhibitor is a potent inhibitor of stromelysin-1 (K(i)=~1µM). The aldehyde carbon of the glyoxal inhibitor was enriched with carbon-13 and using carbon-13 NMR we show that the glyoxal aldehyde carbon is fully hydrated when it is in aqueous solutions (90.4ppm) and also when it is bound to SCD (~92.0ppm). We conclude that the hemiacetal hydroxyl groups of the glyoxal inhibitor are not ionised when the glyoxal inhibitor is bound to SCD. The free enzyme pK(a) values associated with inhibitor binding were 5.9 and 6.2. The formation and breakdown of the signal at ~92ppm due to the bound UK-370106-CO(13)CHO inhibitor depends on pK(a) values of 5.8 and 7.8 respectively. No strong hydrogen bonds are present in free SCD or in SCD-inhibitor complexes. We conclude that the inhibitor glyoxal group is not directly coordinated to the catalytic zinc atom of SCD.

Critically important antimicrobial resistant Enterobacteriaceae in Irish farm effluent and their removal in integrated constructed wetlands.

This study investigated the ability of Integrated Constructed Wetlands (ICWs) to remove critically important antimicrobial resistant organisms (AROs) from farm wastewater. Influent samples from the untreated farm waste and effluent samples taken at the end of the ICW system were collected monthly from four ICWs, serving four different farm types (suckler, dairy, dairy & poultry and pig). Using selective media to screen for the presence of carbapenemase resistant organisms, plasmid mediated and AmpC ß-Lactamase producing organisms (ESBL/pAmpC) and fluoroquinolone resistant organisms, a total of 82 AROs were obtained with the majority being E. coli (n = 79). Statistically significant were the differences on the number of AROs isolated from influent (higher) compared to effluent, as well as a seasonal effect, with less AROs recovered during winter in comparison to other seasons (P < 0.05). On the other hand, there was no significant differences in the recovery of AROs on different farms. The majority of isolates from each of the farms (99%) were multi drug resistant, with 65% resistant to seven or more antimicrobials. A high incidence of tetracycline, trimethoprim/sulfamethoxazole, and ampicillin resistance was common to the isolates from all four farms but there were differences in ESBL levels with 63% of the isolates recovered from Farm 4 (piggery) being ESBLs compared to 18%, 36% and 4.5% recovered from Farms 1 (suckler), 2 (dairy) and 3 (dairy & poultry), respectively. No carbapenemase producing organisms were isolated. Our results showed that ICWs are effective in removing critically important AROs from farm wastewater on all four farm types.

Oxyanion and tetrahedral intermediate stabilisation by subtilisin: detection of a new tetrahedral adduct.

The peptide-derived glyoxal inhibitor Z-Ala-Ala-Phe-glyoxal has been shown to be approximately 10 fold more effective as an inhibitor of subtilisin than Z-Ala-Pro-Phe-glyoxal. Signals at 107.2 ppm and 200.5 ppm are observed for the glyoxal keto and aldehyde carbons of the inhibitor bound to subtilisin, showing that the glyoxal keto and aldehyde carbons are sp(3) and sp(2) hybridised respectively. The signal at 107.2 ppm from the carbon atom attached to the hemiketal oxyanion is formed in a slow exchange process that involves the dehydration of the glyoxal aldehyde carbon. Two additional signals are observed one at 108.2 ppm and the other at 90.9 ppm for the glyoxal keto and aldehyde carbons respectively at pHs 6-8 demonstrating that subtilisin forms an additional tetrahedral adduct with Z-Ala-Ala-Phe-glyoxal in which both the glyoxal keto and aldehyde carbons are sp(3) hybridised. For the first time we can quantify oxyanion stabilisation in subtilisin. We conclude that oxyanion stabilisation is more effective in subtilisin than in chymotrypsin. Using (1)H-NMR we show that the binding of Z-Ala-Ala-Phe-glyoxal to subtilisin raises the pK(a) of the imidazolium ion of the active site histidine residue promoting oxyanion stabilisation. The mechanistic significance of these results is discussed.

Comparison of Accuracy of Patient and Physician Scar Length Estimates Before Mohs Micrographic Surgery for Facial Skin Cancers.

Importance: Patients are satisfied when surgical outcomes meet their expectations. Dissatisfaction with surgical scars is one of the most common reasons that patients sue surgeons who perform Mohs micrographic surgery (MMS). Objective: To measure the accuracy of patient and physician estimations of scar length prior to skin cancer removal with MMS. Design, Setting, and Participants: This cross-sectional study was conducted between December 1, 2017, and February 28, 2018, at the MMS clinic of a single tertiary referral center health system. A total of 101 adults presenting for MMS for treatment of facial skin cancers volunteered for this study, and 86 surgeons who performed the MMS procedure participated. Main Outcomes and Measures: Patients and physicians independently drew the anticipated scar length on the patients' skin prior to surgery. Preoperative estimates by patients and surgeons were compared with actual postoperative scar length. Results: Of the 101 patients who participated, 57 patients (56.4%) were men and 57 patients (56.4%) were aged 65 years or older. Eighty-four patients (83.2%) underestimated scar length, whereas 67 of the 86 surgeons (77.9%) correctly estimated the scar length (P < .001). The actual postoperative scar length was 2.2 (interquartile range, 1.5-3.6) times larger than the patients' preoperative estimate but only 1.1 (interquartile range, 1.0-1.2) times larger than the surgeons' preoperative estimate (P < .001). Preoperative consultation with the surgeon, a personal history of MMS, or patient-directed research about MMS were not associated with improvement of patients' estimations of scar length. Conclusions and Relevance: This study's findings suggest that patients with facial skin cancers have unrealistic expectations regarding scars that measure, on average, less than half the length of the actual postoperative scars. Surgeons appear to accurately estimate the length of most surgical scars and have an opportunity to set realistic patient expectations about scar length before surgery.