Role for targeted resection in the multidisciplinary treatment of metastatic gastrointestinal stromal tumor

The management of advanced gastrointestinal stromal tumors (GISTs) has evolved in the modern era due to the discovery of c-kit mutations and the development of tyrosine kinase inhibitors (TKIs). Until the advent of TKIs such as imatinib, the median survival reported for patients with advanced GIST was 19 months. Although surgery is the treatment of choice for resectable primary GIST, its role in cases of recurrence and metastasis remains to be unclear. This review outlines the potential beneficial role of repeat surgical resection in the multidisciplinary treatment of advanced GIST in the era of TKIs

Equilibrium size of large ring molecules

The equilibrium properties of isolated ring molecules were investigated using an off-lattice model with no excluded volume but with dynamics that preserve the topological class. Using an efficient set of long range moves, chains of more than 2000 monomers were studied. Despite the lack of any excluded volume interaction, the radius of gyration scaled like that of a self avoiding walk, as had been previously conjectured. However this scaling was only seen for chains greater than 500 monomers.Comment: 11 pages, 3 eps figures, latex, psfi

Integrating therapies for surgical adult soft tissue sarcoma patients

Sarcomas are an uncommon group of over 50 different individual histological malignancies arising from mesenchymal (non-epithelial or connective) tissues. Overall, they constitute 1% of human malignancies with an annual incidence rate of fewer than 5 patients per million. Sarcoma may arise from any mesenchymal cell lineages including fat, muscle, or other connective tissues. Due to the rarity of these groups of malignancies, many subtypes were, and still today, are managed as a single entity. This review focused on soft tissue sarcomas with an emphasis on how to integrate therapies for patients with this rare disorder. The role for surgical resection in cure and palliation as well as the relative benefits of adjuvant therapies such as chemotherapy and radiation therapy are discussed

Biliary Bypass with Laparoscopic Choledochoduodenostomy

Laparoscopic choledochoduodenostomy (LCDD) is employed to treat many benign biliary diseases when endoscopic or percutaneous techniques are not feasible. We describe our technique for LCDD, which utilizes common bile duct transection and an end-to-side biliary-enteric anastomosis. This procedure includes the following elements: isolation and transection of the common bile duct, mobilization of the duodenum (Kocher maneuver), inspection of the common bile duct, and end-to-side biliary-enteric anastomosis. Key details and pitfalls are discussed. Over a 5-year period, LCDD was performed on 18 patients. Indications included intractable abdominal pain (10) and choledocholithiasis (8). The majority of patients, 83%, tolerated the operation well with no complications. There was one postoperative intra-abdominal abscess and two anastomotic strictures, one in the immediate postoperative period and the other 9 months after the operation. The median length of stay was 4 days (IQR 3.0–5.3), and there was minimal blood loss. Based on our experience, LCDD with transection and end-to-side biliary-enteric anastomosis is a safe and effective biliary bypass technique

Solitary fibrous tumor

Solitary fibrous tumor (SFT) is a rare tumor of mesenchymal origin that account for less than 2% of all soft tissue masses. Initially identified in the pleura, SFT has been identified in multiple anatomic locations and can arise anywhere in the body. The varying histologic features along with non-specific means of identification have led SFT to be associated with several different names. Over the last several decades, sustained advances through research and technology have led to more reliable methods for differentiating this distinct soft tissue tumor. Advances specifically in immunohistochemistry and molecular diagnostics have identified CD34 as the most consistent marker in SFT, however even this lacks specificity to conclusively narrow down the broad differential for exact identification. More recently the discovery of the NAB2-STAT6 fusion gene has led to more precise diagnosis of SFT. Like many other soft tissue tumors, surgical management is the mainstay of treatment for SFT with emphasis on obtaining tumor-negative margins. Radiation therapy and chemotherapy regimens have not demonstrated global effectiveness, and thus no standardized treatments have been identified. Given the rarity of SFT and current supportive evidence for therapies, management should be focused on tumor extirpation. Nonetheless, individualized therapy, determined within a multidisciplinary setting should be considered

Approach to wild-type gastrointestinal stromal tumors

Gastrointestinal stromal tumors (GISTs) arise from the intestinal pacemaker cells of Cajal. Wild-type gastrointestinal stromal tumors (WT-GIST) are a unique and uncommon subtype of GISTs that lack activating mutations in the tyrosine kinase c-KIT or platelet derived growth factor receptor alpha (PDGFRA) receptors. The lack of these growth-stimulating mutations renders tyrosine kinase receptor inhibitors, such as imatinib mesylate, relatively ineffective against these tumors. WT-GIST arises most commonly due to underlying alternate proliferative signals associated with germ-line, genetic mutations. WT-GIST frequently arises in patients with BRAF mutations, Carney’s Triad or neurofibromatosis type-1 (NF-1). All patients with WT-GIST require a careful examination for germ-line mutations and very close observation for recurrent tumors. Surgery remains a mainstay therapy for these patients. This review aims to discuss the most recent data available on the diagnosis and treatment of WT-GIST

Characteristic length of random knotting for cylindrical self-avoiding polygons

We discuss the probability of random knotting for a model of self-avoiding polygons whose segments are given by cylinders of unit length with radius $r$. We show numerically that the characteristic length of random knotting is roughly approximated by an exponential function of the chain thickness $r$.Comment: 5 pages, 4 figure

Knots and Random Walks in Vibrated Granular Chains

We study experimentally statistical properties of the opening times of knots in vertically vibrated granular chains. Our measurements are in good qualitative and quantitative agreement with a theoretical model involving three random walks interacting via hard core exclusion in one spatial dimension. In particular, the knot survival probability follows a universal scaling function which is independent of the chain length, with a corresponding diffusive characteristic time scale. Both the large-exit-time and the small-exit-time tails of the distribution are suppressed exponentially, and the corresponding decay coefficients are in excellent agreement with the theoretical values.Comment: 4 pages, 5 figure

The impact of members of the Society of University Surgeons on the scholarship of American surgery

Background A core objective of the Society of University Surgeons (SUS) is research focused: to “advance the art and science of surgery through original investigation.” This study sought to determine the current impact of the SUS on academic surgical productivity. Methods Individual faculty data for numbers of publications, citations, and National Institute of Health (NIH) funding history were collected for 4,015 surgical faculty at the top 55 NIH-funded departments of surgery using SCOPUS and the NIH Research Portfolio Online Reporting Tools. SUS membership was determined from membership registry data. Results Overall, 502 surgical faculty (12.5%) were SUS members with 92.7% holding positions of associate or full professor (versus 59% of nonmembers). Median publications (P) and citations (C) among SUS members were P: 112, C: 2,460 versus P: 29, C: 467 for nonmembers (P < .001). Academic productivity was considerably higher by rank for SUS members than for nonmembers: associate professors (P: 61 vs 36, C: 1,199 vs 591, P < .001) and full professors (P: 141 vs 81, C: 3,537 vs 1,856, P < .001). Among full professors, SUS members had much higher rates of NIH funding than did nonmembers (52.6% vs 26%, P < .05) and specifically for R01, P01, and U01 awards (37% vs 17.7%, P < .01). SUS members were 2 times more likely to serve in divisional leadership or chair positions (23.5% vs 10.2%, P < .05). Conclusion SUS society members are a highly productive academic group. These data support the premise that the SUS is meeting its research mission and identify its members as very academically productive contributors to research and scholarship in American surgery and medicine

Onset of entanglement

We have developed a theory of polymer entanglement using an extended Cahn-Hilliard functional, with two extra terms. One is a nonlocal attractive term, operating over mesoscales, which is interpreted as giving rise to entanglement, and the other a local repulsive term indicative of excluded volume interactions. We show how such a functional can be derived using notions from gauge theory. We go beyond the Gaussian approximation, to the one-loop level, to show that the system exhibits a crossover to a state of entanglement as the average chain length between points of entanglement decreases. This crossover is marked by critical slowing down, as the effective diffusion constant goes to zero. We have also computed the tensile modulus of the system, and we find a corresponding crossover to a regime of high modulus.Comment: 18 pages, with 4 figure