Gangrenous appendicitis: No longer complicated.

BACKGROUND: Appendicitis presents on a spectrum ranging from inflammation to gangrene to perforation. Studies suggest that gangrenous appendicitis has lower postoperative infection rates relative to perforated cases. We hypothesized that gangrenous appendicitis could be successfully treated as simple appendicitis, reducing length of stay (LOS) and antibiotic usage without increasing postoperative infections. METHODS: In February 2016, we strictly defined complex appendicitis as a hole in the appendix, extraluminal fecalith, diffuse pus or a well-formed abscess. We switched gangrenous appendicitis to a simple pathway and reviewed all patients undergoing laparoscopic appendectomy for 12 months before (Group 1) and 12 months after (Group 2) the protocol change. Data collected included demographics, appendicitis classification, LOS, presence of a postoperative infection, and 30-day readmissions. RESULTS: Patients in Group 1 and Group 2 were similar, but more cases of simple appendicitis occurred in Group 2. Average LOS for gangrenous appendicitis patients decreased from 2.5 to 1.4 days (p < 0.001) and antibiotic doses decreased from 5.2 to 1.3 (p < 0.001). Only one gangrenous appendicitis patient required readmission, and one patient in each group developed a superficial infection; there were no postoperative abscesses. CONCLUSIONS: Gangrenous appendicitis can be safely treated as simple appendicitis without increasing postoperative infections or readmissions. TYPE OF STUDY: Prognosis study. LEVEL OF EVIDENCE: Level II.

Total Ankle Replacement with Severe Valgus Deformity: Technique and Surgical Strategy.

Correction of severe valgus deformity of the foot and ankle with ankle replacement is challenging. We describe the controversies and specific issues of surgical management and provide a detailed surgical strategy for management of this common deformity. A reliable technique for deltoid reconstruction is also described and illustrated in detail.

Maximizing social model principles in residential recovery settings.

Peer support is integral to a variety of approaches to alcohol and drug problems. However, there is limited information about the best ways to facilitate it. The "social model" approach developed in California offers useful suggestions for facilitating peer support in residential recovery settings. Key principles include using 12-step or other mutual-help group strategies to create and facilitate a recovery environment, involving program participants in decision making and facility governance, using personal recovery experience as a way to help others, and emphasizing recovery as an interaction between the individual and their environment. Although limited in number, studies have shown favorable outcomes for social model programs. Knowledge about social model recovery and how to use it to facilitate peer support in residential recovery homes varies among providers. This article presents specific, practical suggestions for enhancing social model principles in ways that facilitate peer support in a range of recovery residences.

Monoolein lipid phases as incorporation and enrichment materials for membrane protein crystallization.

The crystallization of membrane proteins in amphiphile-rich materials such as lipidic cubic phases is an established methodology in many structural biology laboratories. The standard procedure employed with this methodology requires the generation of a highly viscous lipidic material by mixing lipid, for instance monoolein, with a solution of the detergent solubilized membrane protein. This preparation is often carried out with specialized mixing tools that allow handling of the highly viscous materials while minimizing dead volume to save precious membrane protein sample. The processes that occur during the initial mixing of the lipid with the membrane protein are not well understood. Here we show that the formation of the lipidic phases and the incorporation of the membrane protein into such materials can be separated experimentally. Specifically, we have investigated the effect of different initial monoolein-based lipid phase states on the crystallization behavior of the colored photosynthetic reaction center from Rhodobacter sphaeroides. We find that the detergent solubilized photosynthetic reaction center spontaneously inserts into and concentrates in the lipid matrix without any mixing, and that the initial lipid material phase state is irrelevant for productive crystallization. A substantial in-situ enrichment of the membrane protein to concentration levels that are otherwise unobtainable occurs in a thin layer on the surface of the lipidic material. These results have important practical applications and hence we suggest a simplified protocol for membrane protein crystallization within amphiphile rich materials, eliminating any specialized mixing tools to prepare crystallization experiments within lipidic cubic phases. Furthermore, by virtue of sampling a membrane protein concentration gradient within a single crystallization experiment, this crystallization technique is more robust and increases the efficiency of identifying productive crystallization parameters. Finally, we provide a model that explains the incorporation of the membrane protein from solution into the lipid phase via a portal lamellar phase.

Salvage and storage of infectious disease protein targets in the SSGCID high-throughput crystallization pathway using microfluidics.

The MPCS Plug Maker is a microcapillary-based protein-crystallization system for generating diffraction-ready crystals from nanovolumes of protein. Crystallization screening using the Plug Maker was used as a salvage pathway for proteins that failed to crystallize during the initial observation period using the traditional sitting-drop vapor-diffusion method. Furthermore, the CrystalCards used to store the crystallization experiments set up by the Plug Maker are shown be a viable container for long-term storage of protein crystals without a discernable loss of diffraction quality with time. Use of the Plug Maker with SSGCID proteins is demonstrated to be an effective crystal-salvage and storage method.

SAD phasing using iodide ions in a high-throughput structural genomics environment.

The Seattle Structural Genomics Center for Infectious Disease (SSGCID) focuses on the structure elucidation of potential drug targets from class A, B, and C infectious disease organisms. Many SSGCID targets are selected because they have homologs in other organisms that are validated drug targets with known structures. Thus, many SSGCID targets are expected to be solved by molecular replacement (MR), and reflective of this, all proteins are expressed in native form. However, many community request targets do not have homologs with known structures and not all internally selected targets readily solve by MR, necessitating experimental phase determination. We have adopted the use of iodide ion soaks and single wavelength anomalous dispersion (SAD) experiments as our primary method for de novo phasing. This method uses existing native crystals and in house data collection, resulting in rapid, low cost structure determination. Iodide ions are non-toxic and soluble at molar concentrations, facilitating binding at numerous hydrophobic or positively charged sites. We have used this technique across a wide range of crystallization conditions with successful structure determination in 16 of 17 cases within the first year of use (94% success rate). Here we present a general overview of this method as well as several examples including SAD phasing of proteins with novel folds and the combined use of SAD and MR for targets with weak MR solutions. These cases highlight the straightforward and powerful method of iodide ion SAD phasing in a high-throughput structural genomics environment.

Discovery of leukotriene A4 hydrolase inhibitors using metabolomics biased fragment crystallography.

We describe a novel fragment library termed fragments of life (FOL) for structure-based drug discovery. The FOL library includes natural small molecules of life, derivatives thereof, and biaryl protein architecture mimetics. The choice of fragments facilitates the interrogation of protein active sites, allosteric binding sites, and protein-protein interaction surfaces for fragment binding. We screened the FOL library against leukotriene A4 hydrolase (LTA4H) by X-ray crystallography. A diverse set of fragments including derivatives of resveratrol, nicotinamide, and indole were identified as efficient ligands for LTA4H. These fragments were elaborated in a small number of synthetic cycles into potent inhibitors of LTA4H representing multiple novel chemotypes for modulating leukotriene biosynthesis. Analysis of the fragment-bound structures also showed that the fragments comprehensively recapitulated key chemical features and binding modes of several reported LTA4H inhibitors.

Augmented mobilization and collection of CD34+ hematopoietic cells from normal human volunteers stimulated with granulocyte-colony-stimulating factor by single-dose administration of AMD3100, a CXCR4 antagonist.

BACKGROUND: AMD3100, a selective antagonist of CXCR4, rapidly mobilizes CD34+ hematopoietic progenitor cells (HPCs) from marrow to peripheral blood with minimal side effects. STUDY DESIGN AND METHODS: To further investigate potential clinical utility of AMD3100 for CD34+ cell mobilization and collection, a Phase I study in normal volunteers was performed examining single-dose administration of AMD3100 alone and in combination with a standard 5-day granulocyte-colony-stimulating factor (G-CSF) regimen. RESULTS: AMD3100 (160 microg/kg x 1 on Day 5) significantly increased both G-CSF-stimulated (10 microg/kg/day) mobilization of CD34+ cells (3.8-fold) and leukapheresis yield of CD34+ cells. Moreover, collection of CD34+ cells was comparable between individuals mobilized by a single-dose regimen of AMD3100 (240 microg/kg) and individuals mobilized with a 5-day regimen of G-CSF. AMD3100-mobilized leukapheresis products contained significantly greater numbers of T and B cells compared to G-CSF-stimulated leukapheresis products. CONCLUSION: These findings indicate that AMD3100 can be used alone or as an adjunct to G-CSF to mobilize cells for HPC transplantation.