CaSPA - an Algorithm for Calculation of the Size of Percolating Aggregates

We present an algorithm (CaSPA) which accounts for the effects of periodic boundary conditions in the calculation of size of percolating aggregated clusters. The algorithm calculates the gyration tensor, allowing for a mixture of infinite (macroscale) and finite (microscale) principle moments. Equilibration of a triblock copolymer system from a disordered initial configuration to a hexagonal phase is examined using the algorithm.Comment: 15 pages, 10 figures. Accepted by Computer Physics Communication

Surgeon-Performed Ultrasound as Preoperative Localization Study in Patients with Primary Hyperparathyroidism

Background: Minimally invasive parathyroidectomy is the treatment of choice for single-gland primary hyperparathyroidism. However, the exact location of the abnormal gland has to be established. Sestamibi scintigraphy, computed tomography and ultrasound (US) are commonly used modalities. We describe our experience in a non-academic center with surgeon-performed US (S-US) of the neck as preoperative localization study in patients with primary hyperparathyroidism (PHPT). Methods: Patients with a biochemically proven diagnosis of PHPT and preoperative S-US were included. Data were recorded prospectively. Perioperative gland location was compared to the preoperative S-US to determine sensitivity, specificity and accuracy rates. Results: Two of the 50 patients who underwent S-US were not subjected to surgery. In 85% of the patients analyzed by S-US, the appropriate abnormal gland(s) were identified. In 11%, no gland was identified, but abnormal glands were found during surgery. Sensitivity of S-US in our hospital is 85%, with a positive predictive value of 97%. Conclusions: We achieved a satisfactory sensitivity rate. S-US provides anatomic information to the surgeon which enables a more detailed operation planning, and it is a valuable diagnostic modality for patients with PHPT in our opinion. We hope that our data encourage other centers to implement this technique as well. Copyrigh

Molecular dynamics simulation of the early stages of the synthesis of periodic mesoporous silica

We present results of detailed atomistic modeling of the early stages of the synthesis of periodic mesoporous silica using molecular dynamics. Our simulations lead to the proposal of a mechanism that validates several previous experimental and modeling studies and answers many controversial issues regarding the synthesis of mesoporous silicas. In particular, we show that anionic silicates interact very strongly with cationic surfactants and, significantly adsorb on the surface of micelles, displacing a fraction of previously bound bromide counterions. This induces an increase in micelle size and also enhances silica condensation at the micelle surface. The presence of larger silica aggregates in solution further promotes the growth of micelles and, by binding to surfactant molecules in different micelles, their aggregation. This work demonstrates the crucial role played by silica in influencing, by way of a cooperative templating mechanism, the structure of the eventual liquid-crystal phase, which in turn determines the structure of the porous material

Protocol design and current status of CLIVIT: a randomized controlled multicenter relevance trial comparing clips versus ligatures in thyroid surgery

BACKGROUND: Annually, more than 90000 surgical procedures of the thyroid gland are performed in Germany. Strategies aimed at reducing the duration of the surgical procedure are relevant to patients and the health care system especially in the context of reducing costs. However, new techniques for quick and safe hemostasis have to be tested in clinically relevance randomized controlled trials before a general recommendation can be given. The current standard for occlusion of blood vessels in thyroid surgery is ligatures. Vascular clips may be a safe alternative but have not been investigated in a large RCT. METHODS/DESIGN: CLIVIT (Clips versus Ligatures in Thyroid Surgery) is an investigator initiated, multicenter, patient-blinded, two-group parallel relevance randomized controlled trial designed by the Study Center of the German Surgical Society. Patients scheduled for elective resection of at least two third of the gland for benign thyroid disease are eligible for participation. After surgical exploration patients are randomized intraoperatively into either the conventional ligature group, or into the clip group. The primary objective is to test for a relevant reduction in operating time (at least 15 min) when using the clip technique. Since April 2004, 121 of the totally required 420 patients were randomized in five centers. DISCUSSION: As in all trials the different forms of bias have to be considered, and as in this case, a surgical trial, the role of surgical expertise plays a key role, and will be documented and analyzed separately. This is the first randomized controlled multicenter relevance trial to compare different vessel occlusion techniques in thyroid surgery with adequate power and other detailed information about the design as well as framework. If significant, the results might be generalized and may change the current surgical practice

The Value of Intraoperative Parathyroid Hormone Monitoring in Localized Primary Hyperparathyroidism: A Cost Analysis

Minimally invasive parathyroidectomy (MIP) is the preferred approach to primary hyperparathyroidism (PHPT) when a single adenoma can be localized preoperatively. The added value of intraoperative parathyroid hormone (IOPTH) monitoring remains debated because its ability to prevent failed parathyroidectomy due to unrecognized multiple gland disease (MGD) must be balanced against assay-related costs. We used a decision tree and cost analysis model to examine IOPTH monitoring in localized PHPT. Literature review identified 17 studies involving 4,280 unique patients, permitting estimation of base case costs and probabilities. Sensitivity analyses were performed to evaluate the uncertainty of the assumptions associated with IOPTH monitoring and surgical outcomes. IOPTH cost, MGD rate, and reoperation cost were varied to evaluate potential cost savings from IOPTH. The base case assumption was that in well-localized PHPT, IOPTH monitoring would increase the success rate of MIP from 96.3 to 98.8%. The cost of IOPTH varied with operating room time used. IOPTH reduced overall treatment costs only when total assay-related costs fell below $110 per case. Inaccurate localization and high reoperation cost both independently increased the value of IOPTH monitoring. The IOPTH strategy was cost saving when the rate of unrecognized MGD exceeded 6$12,000 (compared with initial MIP cost of $3733). Setting the positive predictive value of IOPTH at 100% and reducing the false-negative rate to 0% did not substantially alter these findings. Institution-specific factors influence the value of IOPTH. In this model, IOPTH increased the cure rate marginally while incurring approximately 4% additional cost

A randomized two arm phase III study in patients post radical resection of liver metastases of colorectal cancer to investigate bevacizumab in combination with capecitabine plus oxaliplatin (CAPOX) vs CAPOX alone as adjuvant treatment

<p>Abstract</p> <p>Background</p> <p>About 50% of patients with colorectal cancer are destined to develop hepatic metastases. Radical resection is the most effective treatment for patients with colorectal liver metastases offering five year survival rates between 36-60%. Unfortunately only 20% of patients are resectable at time of presentation. Radiofrequency ablation is an alternative treatment option for irresectable colorectal liver metastases with reported 5 year survival rates of 18-30%. Most patients will develop local or distant recurrences after surgery, possibly due to the outgrowth of micrometastases present at the time of liver surgery. This study aims to achieve an improved disease free survival for patients after resection or resection combined with RFA of colorectal liver metastases by adding the angiogenesis inhibitor bevacizumab to an adjuvant regimen of CAPOX.</p> <p>Methods/design</p> <p>The Hepatica study is a two-arm, multicenter, randomized, comparative efficacy and safety study. Patients are assessed no more than 8 weeks before surgery with CEA measurement and CT scanning of the chest and abdomen. Patients will be randomized after resection or resection combined with RFA to receive CAPOX and Bevacizumab or CAPOX alone. Adjuvant treatment will be initiated between 4 and 8 weeks after metastasectomy or resection in combination with RFA. In both arms patients will be assessed for recurrence/new occurrence of colorectal cancer by chest CT, abdominal CT and CEA measurement. Patients will be assessed after surgery but before randomization, thereafter every three months after surgery in the first two years and every 6 months until 5 years after surgery. In case of a confirmed recurrence/appearance of new colorectal cancer, patients can be treated with surgery or any subsequent line of chemotherapy and will be followed for survival until the end of study follow up period as well. The primary endpoint is disease free survival. Secondary endpoints are overall survival, safety and quality of life.</p> <p>Conclusion</p> <p>The HEPATICA study is designed to demonstrate a disease free survival benefit by adding bevacizumab to an adjuvant regime of CAPOX in patients with colorectal liver metastases undergoing a radical resection or resection in combination with RFA.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov Identifier NCT00394992</p

A historical perspective on the discovery of statins

Cholesterol is essential for the functioning of all human organs, but it is nevertheless the cause of coronary heart disease. Over the course of nearly a century of investigation, scientists have developed several lines of evidence that establish the causal connection between blood cholesterol, atherosclerosis, and coronary heart disease. Building on that knowledge, scientists and the pharmaceutical industry have successfully developed a remarkably effective class of drugs—the statins—that lower cholesterol levels in blood and reduce the frequency of heart attacks

Familial Autoimmune Thyroid Disease as a Risk Factor for Regression in Children with Autism Spectrum Disorder: A CPEA Study

A multicenter study of 308 children with Autism Spectrum Disorder (ASD) was conducted through the Collaborative Programs of Excellence in Autism (CPEA), sponsored by the National Institute of Child Health and Human Development, to compare the family history of autoimmune disorders in children with ASD with and without a history of regression. A history of regression was determined from the results of the Autism Diagnostic Interview-Revised (ADI-R). Family history of autoimmune disorders was obtained by telephone interview. Regression was significantly associated with a family history of autoimmune disorders (adjusted OR=1.89; 95% CI: 1.17, 3.10). The only specific autoimmune disorder found to be associated with regression was autoimmune thyroid disease (adjusted OR=2.09; 95% CI: 1.28, 3.41).Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43035/1/10803_2005_Article_71.pd