Cost-Effectiveness Modeling of Prostate-Specific Membrane Antigen Positron Emission Tomography with Piflufolastat F 18 for the Initial Diagnosis of Patients with Prostate Cancer in the United States

BACKGROUND AND OBJECTIVES

Piflufolastat F 18 is a novel prostate-specific membrane antigen (PSMA)-targeted positron emission tomography (PET) radiotracer that is superior to standard of care (SOC) imaging for the initial staging of prostate cancer and the detection of biochemical recurrence. As piflufolastat F 18 has been approved in the United States (US) for this indication, this modeling study assessed the cost effectiveness of piflufolastat F 18 versus fluciclovine F-18, gallium68-PSMA-11 (PSMA 11), and SOC imaging (a mix of bone scans, computed tomography, and magnetic resonance imaging) for the diagnosis and staging of prostate cancer from a US healthcare system perspective.

PERSPECTIVE

A US third-party payer perspective was used, which for this population reflects a mix of commercial and Medicare, considering only direct healthcare costs.

SETTING

This study utilized a tertiary healthcare setting.

METHODS

A decision tree was used to map the diagnostic/treatment pathway, consisting of the proportion of patients with local, regional, distant, or no disease; prostate-specific antigen (PSA) ≤ 1.0 or > 1.0; and accuracy of imaging modalities. A Markov model predicted the long-term outcomes of disease progression according to treatment decisions. Inputs to the model were informed by data from the OSPREY and CONDOR clinical trials, public data, and the literature. Treatment mix included active surveillance, radiation therapy, prostatectomy, androgen deprivation therapy (ADT), and radiation therapy + ADT, informed by expert opinion. Outcomes included life-years (LY), quality-adjusted life-years (QALY), and the incremental cost-effectiveness ratio (ICER). All costs were reported in 2021 US dollars, using the US Bureau of Labor Statistics Consumer Price Index. A willingness-to-pay (WTP) threshold of $150,000 was considered cost effective, consistent with the upper range used as the standard for price benchmarks by the Institute for Clinical and Economic Review. The robustness of the base-case results was assessed in deterministic and probabilistic sensitivity analyses.

RESULTS

Over a lifetime horizon, piflufolastat F 18 had the greatest effectiveness in terms of LYs (6.80) and QALYs (5.33); for the comparators, LYs ranged from 6.58 (SOC) to 6.76 (PSMA 11) and QALYs ranged from 5.12 (SOC) and 5.30 (PSMA 11). Piflufolastat F 18 was more cost effective compared with fluciclovine F 18, PSMA 11, and SOC, with ICERs of $21,122, $55,836, and $124,330 per QALY gained, respectively. Piflufolastat F 18 was associated with the greatest net monetary benefit ($627,918) compared with the other options at a WTP threshold of $150,000. The results of the deterministic and probabilistic sensitivity analyses supported the robustness of the base-case results.

CONCLUSIONS

This study suggests that piflufolastat F 18 is a cost-effective diagnostic option for men with prostate cancer in the US, with higher associated LY, QALY, and greater net monetary benefit than fluciclovine F 18, PSMA 11, and SOC imaging.

Outcome of revision surgery for adverse local tissue reactions in patients with recalled total hip arthroplasty

INTRODUCTION

Recalls of total hip arthroplasty (THA) implants, including metal-on-metal (MoM) THA and dual taper stems, due to increased risk of adverse local tissue reaction (ALTR), represent a challenge for both surgeons and patients. This study aims to analyze the revision surgery outcomes for ALTR in patients with recalled THA implants.

METHODS

A total of 118 consecutive patients who underwent revision surgery due to ALTR with recalled THA were analyzed. Sub-group analysis was performed for recalled MoM THAs, head-neck modular stems, and dual taper neck-stems.

RESULTS

At a mean follow-up of 6.6 years, the complication and reoperation rates of the recalled THAs were 32.2% and 25.4% respectively. The most common post-revision complication was dislocation (16%). Revision of modular taper corrosion THA and high-grade intraoperative tissue damage were risk factors associated with post-revision complications.

CONCLUSION

This study reports high complication and reoperation rates of recalled THAs at mid-term follow-up. The high revision surgery complication rates in both groups suggest the importance of a systematic evaluation of all THA patients with at-risk implants.

LEVEL OF EVIDENCE

Level III, case control retrospective analysis.

Assessing the transition from intravenous to subcutaneous delivery of rituximab: Benefits for payers, health care professionals, and patients with lymphoma

Subcutaneous (SC) administration of rituximab provides an opportunity for reduced patient treatment burden and increased healthcare efficiencies as an alternative to intravenous (IV) rituximab. There is minimal evidence comparing costs associated with SC and IV rituximab in a US setting. This research assessed the impact of transitioning patients from IV to SC rituximab for treatment of non-Hodgkin’s lymphoma (NHL) from the US payer, provider, and patient perspective. We developed a model to estimate cost differences for transitioning 20% of a patient cohort from IV to SC rituximab. We included patients with incident diffuse large B-cell lymphoma, incident and recurrent follicular lymphoma, and incident and recurrent chronic lymphocytic leukemia. In the model, each patient received the same number of doses and that there was no difference in discontinuation between cohorts due to non-inferior efficacy and a similar safety profile. Model inputs were collected from published literature and publicly available data. Scenario analyses tested the impact of availability of low-cost biosimilars. In the base case (1,000,000 covered lives), we estimated a total of 157 patients, with 769 total drug administrations. A transition of 20% of patients from IV to SC was projected to generate $153,000 in payer savings, increase provider capacity by 270 hours, and free 470 hours of patient time. Scenario analyses suggest SC administration will be cost saving for payers even with a market where biosimilars approach 50% market share. A 20% transition to SC rituximab in a single cohort of patients has the potential to generate significant US health system value in the form of payer savings, increased practice capacity, and patient time.

Budget Impact Analysis of Comprehensive Genomic Profiling in Patients With Advanced Non-Small-Cell Lung Cancer

PURPOSE

This study assessed the economic impact of increased use of comprehensive genomic profiling (CGP) versus conventional testing strategies among patients with advanced non-small-cell lung cancer (aNSCLC) from a US commercial health plan perspective.

METHODS

A decision analytic model was developed to estimate the incremental benefits and costs across testing methodologies (CGP v non-CGP), as well as across sample types (tissue-based and liquid-based), for patients with newly diagnosed aNSCLC. Model outcomes included total direct costs, testing costs, and per member per month budget impact. Secondary model outcomes included the number of patients needed to test with CGP to add 1 life-year, and the number of patients needed to test with CGP to treat one individual with a biomarker-matched therapy.

RESULTS

In a hypothetical 2,000,000-member health plan, 790 members were estimated to have incident aNSCLC; 609 underwent molecular diagnostic testing with 122 (20%) tested with CGP (109 tissue-based and 13 liquid) in the base-case. An increase in CGP from 20% to 30% (an additional 61 patients tested with CGP) was associated with 3.11 additional life-years gained and a $0.01 in US dollars per member per month budget impact. Approximately 19.6 patients would need to be tested with CGP versus non-CGP to add one life-year and 5.9 patients would need to be tested with CGP to treat at least one patient with a biomarker-matched therapy.

CONCLUSION

An increase in CGP from 20% to 30% among patients with aNSCLC undergoing molecular diagnostic testing was associated with modest budget impact, most of which was attributable to prolonged survival associated with increased use of more effective treatments.

Antimicrobial resistance point-of-care testing for gonorrhoea treatment regimens: cost-effectiveness and impact on ceftriaxone use of five hypothetical strategies compared with standard care in England sexual health clinics

Background

Widespread ceftriaxone antimicrobial resistance (AMR) threatens Neisseria gonorrhoeae (NG) treatment, with few alternatives available. AMR point-of-care tests (AMR POCT) may enable alternative treatments, including abandoned regimens, sparing ceftriaxone use. We assessed cost-effectiveness of five hypothetical AMR POCT strategies: A-C included a second antibiotic alongside ceftriaxone; and D and E consisted of a single antibiotic alternative, compared with standard care (SC: ceftriaxone and azithromycin).

Aim

Assess costs and effectiveness of AMR POCT strategies that optimise NG treatment and reduce ceftriaxone use.

Methods

The five AMR POCT treatment strategies were compared using a decision tree model simulating 38,870 NG-diagnosed England sexual health clinic (SHC) attendees; A micro-costing approach, representing cost to the SHC (for 2015/16), was employed. Primary outcomes were: total costs; percentage of patients given optimal treatment (regimens curing NG, without AMR); percentage of patients given non-ceftriaxone optimal treatment; cost-effectiveness (cost per optimal treatment gained).

Results

All strategies cost more than SC. Strategy B (azithromycin and ciprofloxacin (azithromycin preferred); dual therapy) avoided most suboptimal treatments (n = 48) but cost most to implement (GBP 4,093,844 (EUR 5,474,656)). Strategy D (azithromycin AMR POCT; monotherapy) was most cost-effective for both cost per optimal treatments gained (GBP 414.67 (EUR 554.53)) and per ceftriaxone-sparing treatment (GBP 11.29 (EUR 15.09)) but with treatment failures (n = 34) and suboptimal treatments (n = 706).

Conclusions

AMR POCT may enable improved antibiotic stewardship, but require net health system investment. A small reduction in test cost would enable monotherapy AMR POCT strategies to be cost-saving.

Global Research Alliance N2 O chamber methodology guidelines: Recommendations for air sample collection, storage, and analysis

Certain aspects in the collection, handling, storage, and subsequent analysis of discrete air samples from non-steady-state flux chambers are critical to generating accurate and unbiased estimates of nitrous oxide (N₂ O) fluxes. The focus of this paper is on air sample collection and storage in small vials (<12 ml) primarily for gas chromatography (GC) analysis. Sample integrity is assured through following simple procedures including storage under pressure and analysis within a few months of collection. Concurrent storage of standards in an identical manner to samples is recommended and allows the storage period to be reliably extended. In the laboratory, an autosampler is typically used in batch analysis of ∼200 sequentially analyzed samples by GC with an electron capture detector (ECD). Some comparisons are given between GC and alternatives including optical N₂ O detectors that are increasingly being used for high-precision N₂ O measurement. The importance of calibration and traceability of gas standards is discussed, where high-quality standards ensure the most accurate assessment of N₂ O concentration and comparability between laboratories. The calibration allows a consistent and best estimate of flux to be derived.

Structural Competency: Curriculum for Medical Students, Residents, and Interprofessional Teams on the Structural Factors That Produce Health Disparities

Introduction

Research on disparities in health and health care has demonstrated that social, economic, and political factors are key drivers of poor health outcomes. Yet the role of such structural forces on health and health care has been incorporated unevenly into medical training. The framework of structural competency offers a paradigm for training health professionals to recognize and respond to the impact of upstream, structural factors on patient health and health care.

Methods

We report on a brief, interprofessional structural competency curriculum implemented in 32 distinct instances between 2015 and 2017 throughout the San Francisco Bay Area. In consultation with medical and interprofessional education experts, we developed open-ended, written-response surveys to qualitatively evaluate this curriculum's impact on participants. Qualitative data from 15 iterations were analyzed via directed thematic analysis, coding language, and concepts to identify key themes.

Results

Three core themes emerged from analysis of participants' comments. First, participants valued the curriculum's focus on the application of the structural competency framework in real-world clinical, community, and policy contexts. Second, participants with clinical experience (residents, fellows, and faculty) reported that the curriculum helped them reframe how they thought about patients. Third, participants reported feeling reconnected to their original motivations for entering the health professions.

Discussion

This structural competency curriculum fills a gap in health professional education by equipping learners to understand and respond to the role that social, economic, and political structural factors play in patient and community health.

Use of the Aptima mRNA high-risk human papillomavirus (HR-HPV) assay compared to a DNA HR-HPV assay in the English cervical screening programme: a decision tree model based economic evaluation

OBJECTIVE

To estimate the impact of using the Aptima messenger RNA (mRNA) high-risk human papilloma virus (HR-HPV) assay versus a DNA HR-HPV assay in a primary HPV cervical screening programme.

DESIGN

One hypothetical cohort followed for 3 years through HPV primary cervical screening.

SETTING

England.

PARTICIPANTS

A hypothetical cohort of women aged 25-65 years tested in the National Health Service (NHS) Cervical Screening Programme (CSP) for first call or routine recall testing.

METHODS

A decision tree parameterised with data from the CSP (2017/18) and the HORIZON study. Uncertainty analyses were conducted using data from the FOCAL and GAST studies, other DNA HPV tests in addition to one-way and probabilistic sensitivity and scenarios analyses, to test the robustness of results.

INTERVENTIONS

Aptima mRNA HR-HPV assay and a DNA HR-HPV assay (cobas 4800 HPV assay).

MAIN OUTCOME MEASURES

Primary: total colposcopies and total costs for the cohort. Secondary: total HPV and cytology tests, number lost to follow-up.

RESULTS

At baseline for a population of 2.25 million women, an estimated £15.4 million (95% credibility intervals (CI) £6.5 to 24.1 million) could be saved and 28 009 (95% CI 27 499 to 28 527) unnecessary colposcopies averted if Aptima mRNA assays are used instead of a DNA assay, with 90 605 fewer unnecessary HR-HPV and 253 477 cytology tests performed. These savings are due to a lower number of HPV positive samples in the mRNA arm. When data from other primary HPV screening trials were compared, results indicated that using the Aptima mRNA assay generated cost savings and reduced testing in every scenario.

CONCLUSION

Using the Aptima mRNA assay versus a DNA assay would almost certainly yield cost savings and reduce unnecessary testing and procedures, benefiting the NHS and women in the CSP.

Modelling-based evaluation of the costs, benefits and cost-effectiveness of multipathogen point-of-care tests for sexually transmitted infections in symptomatic genitourinary medicine clinic attendees

OBJECTIVES

To quantify the costs, benefits and cost-effectiveness of three multipathogen point-of-care (POC) testing strategies for detecting common sexually transmitted infections (STIs) compared with standard laboratory testing.

DESIGN

Modelling study.

SETTING

Genitourinary medicine (GUM) services in England.

POPULATION

A hypothetical cohort of 965 988 people, representing the annual number attending GUM services symptomatic of lower genitourinary tract infection.

INTERVENTIONS

The decision tree model considered costs and reimbursement to GUM services associated with diagnosing and managing STIs. Three strategies using hypothetical point-of-care tests (POCTs) were compared with standard care (SC) using laboratory-based testing. The strategies were: A) dual POCT for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG); B) triplex POCT for CT-NG and Mycoplasma genitalium (MG); C) quadruplex POCT for CT-NG-MG and Trichomonas vaginalis (TV). Data came from published literature and unpublished estimates.

PRIMARY AND SECONDARY OUTCOME MEASURES

Primary outcomes were total costs and benefits (quality-adjusted life years (QALYs)) for each strategy (2016 GB, £) and associated incremental cost-effectiveness ratios (ICERs) between each of the POC strategies and SC. Secondary outcomes were inappropriate treatment of STIs, onward STI transmission, pelvic inflammatory disease in women, time to cure and total attendances.

RESULTS

In the base-case analysis, POC strategy C, a quadruplex POCT, was the most cost-effective relative to the other strategies, with an ICER of £36 585 per QALY gained compared with SC when using microcosting, and cost-savings of £26 451 382 when using tariff costing. POC strategy C also generated the most benefits, with 240 467 fewer clinic attendances, 808 fewer onward STI transmissions and 235 135 averted inappropriate treatments compared with SC.

CONCLUSIONS

Many benefits can be achieved by using multipathogen POCTs to improve STI diagnosis and management. Further evidence is needed on the underlying prevalence of STIs and SC delivery in the UK to reduce uncertainty in economic analyses.

Rapid testing and treatment for sexually transmitted infections improve patient care and yield public health benefits

A service evaluation of Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) testing and result notification in patients attending a rapid testing service (Dean Street Express [DSE]) compared with those attending an existing 'standard' sexual health clinic (56 Dean Street [56DS]), and modelling the impact of the new service from 1 June 2014 to 31 May 2015.

PRIMARY OUTCOME

time from patients' sample collection to notification of test results at DSE compared with 56DS. Secondary outcomes estimated using a model: number of transmissions prevented and the number of new partner visits avoided and associated cost savings achieved due to rapid testing at DSE. In 2014/15, there were a total of 81,352 visits for CT/NG testing across 56DS (21,086) and DSE (60,266). Rapid testing resulted in a reduced mean time to notification of 8.68 days: 8.95 days for 56DS (95% CI 8.91-8.99) compared to 0.27 days for DSE (95% CI 0.26-0.28). Our model estimates that rapid testing at DSE would lead to 196 CT and/or NG transmissions prevented (2.5-97.5% centile range = 6-956) and lead to annual savings attributable to reduced numbers of partner attendances of £124,283 (2.5-97.5% centile range = £4260-590,331). DSE, a rapid testing service for asymptomatic infections, delivers faster time to result notification for CT and/or NG which enables faster treatment, reduces infectious periods and leads to fewer transmissions, partner attendances and clinic costs.

Respiratory-syncytial-virus- and rhinovirus-related bronchiolitis in children aged <2 years in an English district general hospital

BACKGROUND

Bronchiolitis is the most common reason for hospitalization in young children. In addition to respiratory syncytial virus (RSV), other viruses have been increasingly implicated. Guidance on testing has also changed.

AIMS

To compare clinicopathological outcomes in young children admitted with bronchiolitis due to RSV in comparison with rhinovirus (RV), and identify associated risk/epidemiological factors.

METHODS

Children aged less than two years admitted to hospital with a clinical diagnosis of bronchiolitis with positive results for either RSV or RV were included in this study. Polymerase-chain-reaction-negative cases using an extended respiratory virus panel served as a control group. Retrospective data were collected on sex, risk factors, respiratory support, intravenous fluids and antibiotics. Outcomes such as length of stay (LOS) and need for transfer to the high-dependency unit/paediatric intensive care unit were included.

FINDINGS

Two hundred and twenty-seven out of 437 nasopharyngeal aspirate samples were positive for either RSV (N = 162) or RV (N = 65). The median age of cases was three months and 75% had at least one risk factor. Risk factors were higher in the RV group (P = 0.004). RV accounted for the majority of cases outside the RSV season (P < 0.01). RV-associated bronchiolitis had a longer LOS (more than seven days) (P < 0.05) and increased need for chest X-rays and/or antibiotics (P < 0.05). Use of intravenous fluids and respiratory support were higher in the RV group, but the difference was not significant.

CONCLUSIONS

RV is the second most common pathogen associated with bronchiolitis and is isolated all year round. This may be important in those with risk factors resulting in prolonged LOS. Further research is necessary to establish the exact role of RV in this common condition, particularly outside the traditional RSV season.

Hitting the Optimal Vaccination Percentage and the Risks of Error: Why to Miss Right

OBJECTIVE

To determine the optimal level of vaccination coverage defined as the level that minimizes total costs and explore how economic results change with marginal changes to this level of coverage.

METHODS

A susceptible-infected-recovered-vaccinated model designed to represent theoretical infectious diseases was created to simulate disease spread. Parameter inputs were defined to include ranges that could represent a variety of possible vaccine-preventable conditions. Costs included vaccine costs and disease costs. Health benefits were quantified as monetized quality adjusted life years lost from disease. Primary outcomes were the number of infected people and the total costs of vaccination. Optimization methods were used to determine population vaccination coverage that achieved a minimum cost given disease and vaccine characteristics. Sensitivity analyses explored the effects of changes in reproductive rates, costs and vaccine efficacies on primary outcomes. Further analysis examined the additional cost incurred if the optimal coverage levels were not achieved.

RESULTS

Results indicate that the relationship between vaccine and disease cost is the main driver of the optimal vaccination level. Under a wide range of assumptions, vaccination beyond the optimal level is less expensive compared to vaccination below the optimal level. This observation did not hold when the cost of the vaccine cost becomes approximately equal to the cost of disease.

DISCUSSION AND CONCLUSION

These results suggest that vaccination below the optimal level of coverage is more costly than vaccinating beyond the optimal level. This work helps provide information for assessing the impact of changes in vaccination coverage at a societal level.

HTMD: High-Throughput Molecular Dynamics for Molecular Discovery

Recent advances in molecular simulations have allowed scientists to investigate slower biological processes than ever before. Together with these advances came an explosion of data that has transformed a traditionally computing-bound into a data-bound problem. Here, we present HTMD, a programmable, extensible platform written in Python that aims to solve the data generation and analysis problem as well as increase reproducibility by providing a complete workspace for simulation-based discovery. So far, HTMD includes system building for CHARMM and AMBER force fields, projection methods, clustering, molecular simulation production, adaptive sampling, an Amazon cloud interface, Markov state models, and visualization. As a result, a single, short HTMD script can lead from a PDB structure to useful quantities such as relaxation time scales, equilibrium populations, metastable conformations, and kinetic rates. In this paper, we focus on the adaptive sampling and Markov state modeling features.

An Implementation of the Smooth Particle Mesh Ewald Method on GPU Hardware

The smooth particle mesh Ewald summation method is widely used to efficiently compute long-range electrostatic force terms in molecular dynamics simulations, and there has been considerable work in developing optimized implementations for a variety of parallel computer architectures. We describe an implementation for Nvidia graphical processing units (GPUs) which are general purpose computing devices with a high degree of intrinsic parallelism and arithmetic performance. We find that, for typical biomolecular simulations (e.g., DHFR, 26K atoms), a single GPU equipped workstation is able to provide sufficient performance to permit simulation rates of ≈50 ns/day when used in conjunction with the ACEMD molecular dynamics package (1) and exhibits an accuracy comparable to that of a reference double-precision CPU implementation.

U.S. and International In-Hospital Costs of Extracorporeal Membrane Oxygenation: a Systematic Review

CONTEXT

The in-hospital costs of extracorporeal membrane oxygenation (ECMO) have not been well established.

OBJECTIVE

To evaluate the in-hospital costs of ECMO technology in both US and non-US settings for all patient types.

DATA SOURCES

Systematic review of English-language articles, using the PubMed, Embase, Web of Science and EconLit databases. Searches consisted of the terms 'ECMO' AND 'health expenditures' or 'resource use' or 'costs' or 'cost analysis' or 'cost(-)effectiveness' or 'cost(-)benefit' or 'cost(-)utility' or 'economic(-)evaluation' or 'economic' or 'QALY' or 'cost per quality-adjusted life year'.

STUDY SELECTION

Only full scientific research articles were included. The exclusion criteria included papers that focused on pumpless ECMO, simulation training or decision support systems; papers that did not include human subjects or were not written in English; papers that did not mention ECMO, costs, economics or resource utilization; and papers that included only outside-hospital, infrastructure capital or device capital costs.

DATA EXTRACTION

Data extraction was completed by one author, using predefined criteria.

RESULTS

From the database searches, 1371 results were returned, 226 records underwent a full review and 18 studies were included in the final review. Three papers studied adult populations, two studied adult and paediatric populations, five studied only paediatric populations, one studied a paediatric and neonatal population, and the remaining seven exclusively examined ECMO in neonatal populations. The sample sizes ranged from 8 to 8753 patients. ECMO for respiratory conditions was the most common diagnosis category, followed by congenital diaphragmatic hernia (CDH) and then cardiac conditions. Most papers (n = 14) used retrospective cost collection. Only eight papers stated the perspective of the cost analysis. The results show a large variation in the cost of ECMO over multiple cost categories (e.g., range of total in-hospital costs of treatment: USD 42,554-537,554 [in 2013 values]). In the U.S.A., the reported costs of ECMO were highest for CDH repair, followed by cardiac conditions, and lowest for respiratory conditions. The US charges were highest for cardiac conditions. Outside the U.S.A., the ECMO cost was highest for cardiac conditions, followed by respiratory conditions, and lowest for CDH repair. No non-US studies reported charges.

CONCLUSION

The current literature shows that a large variation exists in the in-hospital cost estimates for ECMO. Further research is needed to understand how the diagnosis, setting and other factors relate to this variation in the cost of this technology. Reliable costing methodologies and cost information will be critical to inform policymakers and stakeholders wishing to maximize the value of advanced medical technologies such as ECMO.

Comparison of open and minimally invasive surgery for intradural-extramedullary spine tumors

OBJECT

Patients with symptomatic intradural-extramedullary (ID-EM) tumors may be successfully treated with resection of the lesion and decompression of associated neural structures. Studies of patients undergoing open resection of these tumors have reported high rates of gross-total resection (GTR) with minimal long-term neurological deficit. Case reports and small case series have suggested that these patients may be successfully treated with minimally invasive surgery (MIS). These studies have been limited by small patient populations. Moreover, there are no studies directly comparing perioperative outcomes between patients treated with open resection and MIS. The objective of this study was to compare perioperative outcomes in patients with ID-EM tumors treated using open resection or MIS.

METHODS

A retrospective review was performed using data collected from 45 consecutive patients treated by open resection or MIS for ID-EM spine tumors. These patients were treated over a 9-year period between April 2003 and October 2012 at Northwestern University and the University of Chicago. Statistical analysis was performed to compare perioperative outcomes between the two groups.

RESULTS

Of the 45 patients in the study, 27 were treated with the MIS approach and 18 were treated with the open approach. Operative time was similar between the two groups: 256.3 minutes in the MIS group versus 241.1 minutes in the open group (p = 0.55). Estimated blood loss was significantly lower in the MIS group (133.7 ml) compared with the open group (558.8 ml) (p < 0.01). A GTR was achieved in 94.4% of the open cases and 92.6% of the MIS cases (p = 0.81).

The mean hospital stay was significantly shorter in the MIS group (3.9 days) compared with the open group (6.1 days) (p < 0.01). There was no significant difference between the complication rates (p = 0.32) and reoperation rates (p = 0.33) between the two groups. Multivariate analysis demonstrated an increased rate of complications in cervical spine tumors (OR 15, p = 0.05).

CONCLUSIONS

Thoracolumbar ID-EM tumors may be safely and effectively treated with either the open approach or an MIS approach, with an equivalent rate of GTR, perioperative complication rate, and operative time. Patients treated with an MIS approach may benefit from a decrease in operative blood loss and shorter hospital stays.

AceCloud: Molecular Dynamics Simulations in the Cloud

We present AceCloud, an on-demand service for molecular dynamics simulations. AceCloud is designed to facilitate the secure execution of large ensembles of simulations on an external cloud computing service (currently Amazon Web Services). The AceCloud client, integrated into the ACEMD molecular dynamics package, provides an easy-to-use interface that abstracts all aspects of interaction with the cloud services. This gives the user the experience that all simulations are running on their local machine, minimizing the learning curve typically associated with the transition to using high performance computing services.

K-Wire fracture during minimally invasive transforaminal lumbar interbody fusion: Report of six cases and recommendations for avoidance and management

BACKGROUND

Although rare, minimally invasive spine techniques do have the risk of intraoperative device failure. Kirschner wire (K-wire) fractures during minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) have not been previously reported. This report focuses on the incidence of k-wire fractures following MI-TLIF and describes techniques to help avoid and treat these fractures when they occur.

METHODS

INCLUSION CRITERIA

(i) patients underwent 1, 2, or 3 level MI-TLIF over a 10-year period and (ii) had a k-wire fracture leading to a retained fragment. Exclusion criteria included: >10° coronal curves, significant sagittal malalignment, infection, and preoperative instrumentation failure.

RESULTS

Of 513 patients undergoing MI-TLIF, 6 (1.2%) sustained k-wire fracture (3 males, 3 females, mean age 43 ± 13 years). Complications included k-wire fracture alone (4 patients), cerebrospinal fluid (CSF) leak (1 patient), and both ileus and revision for hardware removal (1 patient). All six patients went home postoperatively. The mean follow-up duration was 27.7 ± 37.4 months. All retained k-wire fragments were located in the vertebral bodies at the tip of the pedicle screws; none breached the anterior cortex of the vertebral bodies. None of the k-wires migrated at final follow-up 7.8 years (93.7 months) postoperatively. Furthermore, no complications were attributed to retained k-wires.

CONCLUSIONS

K-wire fractures during MI-TLIF are rare (incidence of 1.2%) and retained k-wire segments led to no postoperative complications (e.g. no migration).

Reranking docking poses using molecular simulations and approximate free energy methods

Fast and accurate identification of active compounds is essential for effective use of virtual screening workflows. Here, we have compared the ligand-ranking efficiency of the linear interaction energy (LIE) method against standard docking approaches. Using a trypsin set of 1549 compounds, we performed 12,250 molecular dynamics simulations. The LIE method proved effective but did not yield results significantly better than those obtained with docking codes. The entire database of simulations is released.

Kinetic characterization of fragment binding in AmpC β-lactamase by high-throughput molecular simulations

Small molecules used in fragment-based drug discovery form multiple, promiscuous binding complexes difficult to capture experimentally. Here, we identify such binding poses and their associated energetics and kinetics using molecular dynamics simulations on AmpC β-lactamase. Only one of the crystallographic binding poses was found to be thermodynamically favorable; however, the ligand shows several binding poses within the pocket. This study demonstrates free-binding molecular simulations in the context of fragment-to-lead development and its potential application in drug design.

In situ studies of phase separation and crystallization directed by Marangoni instabilities during spin-coating

Results of a pioneering study are presented in which for the first time, crystallization, phase separation and Marangoni instabilities occurring during the spin-coating of polymer blends are directly visualized, in real-space and real-time. The results provide exciting new insights into the process of self-assembly, taking place during spin-coating, paving the way for the rational design of processing conditions, to allow desired morphologies to be obtained.

An exploration of violence, mental health and substance abuse in post-conflict Guatemala

Guatemala's 36-year civil war officially ended in December 1996 after some 200,000 deaths and one million refugees. Despite the ceasefire, Guatemala continues to be a violent country with one of the highest homicide rates in the world. We investigated potential associations between violence, mental health, and substance abuse in post-conflict Guatemala using a community-based survey of 86 respondents living in urban and rural Guatemala. Overall, 17.4% of our respondents had at least one, direct violent experience during the civil war. In the post-conflict period, 90.7% of respondents reported being afraid that they might be hurt by violence, 40.7% screened positive for depression, 50.0% screened positive for PTSD, and 23.3% screened positive for alcohol dependence. Potential associations between prior violent experiences during the war and indicators of PTSD and aspects of alcohol dependence were found in regression-adjusted models (p < 0.05). Certain associations between prior civil war experiences, aspects of PTSD and alcohol dependence in this cohort are remarkable, raising concerns for the health and safety of the largely indigenous populations we studied. Higher than expected rates of depression, PTSD, and substance abuse in our cohort may be related to the ongoing violence, injury and fear that have persisted since the end of the civil war. These, in turn, have implications for the growing medical and surgical resources needed to address the continuing traumatic and post-traumatic complications in the post-conflict era. Limitations of the current study are discussed. These findings are useful in beginning to understand the downstream effects of the Guatemalan civil war, although a much larger, randomly sampled survey is now needed.

Accuracy of the lattice-Boltzmann method using the Cell processor

Accelerator processors like the new Cell processor are extending the traditional platforms for scientific computation, allowing orders of magnitude more floating-point operations per second (flops) compared to standard central processing units. However, they currently lack double-precision support and support for some IEEE 754 capabilities. In this work, we develop a lattice-Boltzmann (LB) code to run on the Cell processor and test the accuracy of this lattice method on this platform. We run tests for different flow topologies, boundary conditions, and Reynolds numbers in the range Re=6-350 . In one case, simulation results show a reduced mass and momentum conservation compared to an equivalent double-precision LB implementation. All other cases demonstrate the utility of the Cell processor for fluid dynamics simulations. Benchmarks on two Cell-based platforms are performed, the Sony Playstation3 and the QS20/QS21 IBM blade, obtaining a speed-up factor of 7 and 21, respectively, compared to the original PC version of the code, and a conservative sustained performance of 28 gigaflops per single Cell processor. Our results suggest that choice of IEEE 754 rounding mode is possibly as important as double-precision support for this specific scientific application.

An Integrated Instrument Control and Informatics System for Combinatorial Materials Research

The use of high-throughput synthesis and characterization techniques is increasingly prevalent in materials science research. We describe the London University Search Instrument, a research apparatus designed for the high-throughput synthesis and characterization of thick-film sample libraries of ceramic compounds. The instrument is constructed largely from commodity components, which pose particular engineering challenges for achieving the automated operation required for efficient high-throughput experimentation. This paper describes the architecture and implementation of the software system that provides integrated instrument control and data management functions.

Selective cleavage of N-benzyl-protected secondary amines by triphosgene

A series of competition experiments has revealed that selective cleavage of N-benzyl-protected secondary amines can be achieved with triphosgene, thereby providing a useful range of carbamoyl chlorides.

Monomeric uni-ligated aluminates

The tetradentate ligand, common name Salban(But)H4 (N,N'-bis(2-hydroxy-3,5-di-tert-butylbenzyl)-1,4-diaminobutane) combines with appropriate amounts of LiAlH4 to produce the unique monomeric, uni-ligated aluminate [Salban(But)Al]Li(thf)2 (1) and the bimetallic derivative Salban(But)(AlH2Li(thf)2)2 (2).

Group 13 compounds incorporating Salen ligands

In a previous review it was predicted that "the reactivity of five-coordinate complexes would certainly be different than that of the four-coordinate derivatives". Structurally and spectroscopically, there is very little difference in the higher-coordinate compounds when compared to the four-coordinate derivatives. However, the prediction was remarkably accurate, if not a bit understated, for the reactivity of these compounds. There appears to be a tremendous potential in catalysis and synthesis for the five-coordinate derivatives, far more possibilities than exist for the lower-coordinate derivatives. Furthermore, the higher-coordinate derivatives are rarely air or moisture sensitive and, thus, may be handled under a wider range of conditions. Although reactions such as oxirane and lactide polymerizations are fairly well-known now with five- and six-coordinate aluminum compounds, the potential of these compounds has only begun to be developed. It is easy to imagine that these types of compounds will see wider use than the related transition-metal compounds.

Measurement of plasma oestradiol after an injection of a gonadotrophin as a test for neutered bitches

Twenty-eight bitches with unknown reproductive histories were injected intravenously with either human chorionic gonadotrophin (hCG) or equine chorionic gonadotrophin (eCG) (pregnant mare's serum gonadotrophin) and their oestradiol responses were measured at the time of the injection and 90 minutes later. They were at various stages of the oestrous cycle as determined by histology and a progesterone assay for luteal function. Twenty-six of them were considered to be entire because they showed either an increase in plasma oestradiol over preinjection values or steady high values. The ovaries were removed from 25 of these animals and the other probably had a remnant of ovary because it came into oestrus some weeks later. In two remaining bitches no oestradiol could be detected either before or after the injection of gonadotrophin and they were predicted to have been neutered, which was confirmed at laparotomy. In the entire bitches, the highest plasma oestradiol concentration was measured during metoestrus and the lowest during anoestrus.

A study of the aetiology of pseudopregnancy in the bitch and the effect of cabergoline therapy

Thirty-two permanently pseudopregnant bitches were treated with the anti-prolactin drug cabergoline. They had all been ovariohysterectomised up to five months after their last season, in some cases over two years previously, when most were reported as showing no signs of the condition. The clinical signs were mainly behavioural, the majority being aggressive, and a small number were lactating. The efficiency of the cabergoline therapy was classified by the owners as 'excellent' or 'good' in 50 per cent of the cases, and fair in 36 per cent. The rate of success was markedly better than in similar cases treated with reproductive steroids. In all but one of the bitches, the plasma prolactin concentrations were basal.

Effect and mechanisms of the anti-prolactin drug cabergoline on pseudopregnancy in the bitch

A potent anti-prolactin drug, cabergoline, administered orally for five days, was clinically successful in treating three different clinical manifestations of pseudopregnancy in referred bitches. The clinical conditions treated were categorised as standard pseudopregnant bitches (n = 8), those previously unsuccessfully treated with hormones (n = 10) and those which had behavioural pseudopregnancy following ovariohysterectomy (n = 8). The number of bitches whose owners reported a 'good' response was seven out of eight, six out of 10 and six out of eight, respectively. There were very few side effects in that only one bitch vomited following treatment. The clinical response did not necessarily appear to be related to an alteration in circulating prolactin concentrations, suggesting that the drug may have a direct effect on the tissues as well as in most cases reducing the plasma prolactin concentrations.

Effects of castration on luteinizing hormone secretion and response to gonadotrophin-releasing hormone in sheep infected with Trypanosoma congolense

The effects of trypanosomiasis on the endocrine function of the hypothalamo-pituitary-gonadal axis were investigated before and after castration of Scottish Blackface rams infected with Trypanosoma congolense and uninfected controls. Blood samples were collected at 15-min intervals for 6 h before and at 10, 20, 40, 60, 80, 100 and 120 min after injection of synthetic gonadotrophin-releasing hormone (GnRH, 20 micrograms iv) 2 days before infection and 26 and 54 days after infection, with castration being performed 28 days after infection. Mean luteinizing hormone (LH) pulse amplitude was higher (3.3 +/- 0.2 vs 2.6 +/- 0.3 ng/ml) and mean plasma testosterone concentration was lower (4.1 +/- 0.6 vs 7.6 +/- 1.2 nmol/l) in infected vs control rams 26 days after infection (p < 0.05). Mean plasma LH concentration and pulse amplitude increased in both groups after castration but both were significantly lower in infected compared to control rams (6.6 +/- 1.5 and 13.0 +/- 2.2 ng/ml, p < 0.01; 7.7 +/- 0.9 and 11.6 +/- 0.9 ng/ml, p < 0.001), respectively. However, LH responses to exogenous GnRH were similar in infected and control rams at each stage of the experiment, suggesting that the smaller increase in plasma LH after castration in infected rams was not caused by reduced responsiveness of the pituitary to GnRH but by alterations in GnRH secretion by the hypothalamus or its transport to the adenohypophysis. These results also demonstrate that impairment of testosterone secretion within 4 weeks of T. congolense infection in sheep may be due to testicular rather than pituitary effects.

Vaginal cysts causing tenesmus in a bitch

An eight-year-old female border collie was referred with a two-month history of faecal tenesmus. Ultrasonography and radiology identified fluid-filled masses in the cranial vagina. The fluid was drained from the vaginal cysts via an episiotomy and the clinical signs resolved. Histological examination confirmed that the cysts were of urogenital origin. This is believed to be the first report of vaginal cysts causing faecal tenesmus in the dog.

Transgenic science

The ability to manipulate the genome of the whole animal has, for the past 10 years, provided researchers with an alternative route of inquiry into many complex biological processes. Transgenic animals have numerous applications, encompassing a wide range of different disciplines, but they have proved especially useful in the investigation of gene regulation and gene function within the context of the living animal. This review describes the different techniques which have been used to produce transgenic animals and highlights advances which have been achieved using the transgenic approach.

Termination of early pregnancy in sheep with dinoprost or cloprostenol: comparison of two commercial preparations

The response of the ovine corpus luteum of pregnancy to the luteolytic effect of prostaglandin F2 alpha (dinoprost) and its analogue, cloprostenol, was tested in both superovulated and untreated ewes by monitoring plasma progesterone concentrations at the time of 'material recognition' and beyond (days 13 to 30). On days 13, 16 and 28, the majority of the superovulated ewes were refractory to 10 mg of dinoprost. The luteolytic efficacy of 250 micrograms of cloprostenol was compared with 10 mg of dinoprost on day 20 of pregnancy in superovulated and untreated animals and the two prostaglandins were also compared on days 26 and 30 in animals previously unresponsive to dinoprost. Generally, cloprostenol was more effective than dinoprost because there was less refractoriness on day 20 and no refractoriness on days 26 and 30 to this prostaglandin. No difference in the sensitivity to this drug was found between the superovulated and untreated groups on days 20 and 26.

Problems associated with ultrasonography of the canine ovary around the time of ovulation

Real-time B-mode ultrasound imaging was carried out, using a scanner of moderate quality, on 40 fresh bitch cadavers to identify the presence of ovaries and significant ovarian structures. The results indicated that accurate identification of the ovaries depended on the presence of significant follicles or corpora lutea (CL). The findings were verified at post-mortem examination. The study was continued by scanning 35 live bitches using three different scanning units of increasingly improved quality to show that the process of ovulation could be assessed with reasonable accuracy with improved quality of equipment, although the exact fate of the follicle could not be imaged. The results were judged against assays for blood circulating progesterone. A final group of seven live bitches were scanned with a high-grade scanner using an annular phased-array transducer to attempt to image the process of ovulation. The non-echogenic follicle disappeared and was replaced by the CL that was hypoechoic with respect to surrounding tissue, thus allowing accurate assessment of the time of ovulation. This was confirmed by progesterone assay.

Comparison of endocrine changes and ultrasound as means of identifying ovulation in the bitch

Twenty bitches were monitored through pro-oestrus and oestrus using both circulating plasma hormone levels and ultrasonic examination of the ovaries. Using luteinising hormone (LH) as being the generally accepted optimum indicator of the day of ovulation, comparisons were made of the accuracy of progesterone and ultrasound to identify ovulation. Progesterone agreed with LH in 12 of 20 bitches and was within one day in seven of the other eight. Ultrasound was less accurate in that only four of the 16 estimates agreed, with a further six being within one day. However, if only the bitches which were examined by ultrasound with the latest equipment were included, while only three of 11 coincided, six of the remaining eight were within one day of the LH estimated ovulation. It is concluded that, at present, of the rapid assessments, the measurement of plasma progesterone is a better estimator of ovulation than ultrasound.

Rapid isolation of human CD34 hematopoietic stem cells--purging of human tumor cells

Human CD34+ hematopoietic stem cells were purified using a new technology in which monoclonal antibodies are covalently immobilized on polystyrene surfaces. The CD34+ cell isolation scheme involved three sequential processes: (1) purification of bone marrow mononuclear cells; (2) enrichment of CD34+ cells using covalently immobilized soybean agglutinin; and (3) positive selection of CD34+ cells using polystyrene surfaces coated with the anti-CD34 monoclonal antibody ICH3. CD34+ cells purified by this process have both low-to-medium forward light scatter and low 90 degrees light-scatter properties. Moreover, the purified CD34+ cells are greater than 85% viable, express appropriate characteristic surface antigens, and are 10-50-fold enriched in short- and long-term hematopoietic activity. CD34+ cells collected in this manner from bone marrow samples contaminated with radiolabeled breast carcinoma, neuroblastoma, acute myelogenous leukemia, or small cell lung carcinoma cells were 99.9% depleted of the tumor cells. The CD34+ cell selection devices are sterile and are easily scaled-up to process clinical scale bone marrow samples.

Ovulation, fertilization and early embryonic development in the bitch (Canis familiaris)

Using circulating plasma hormone estimations, ovulation was monitored in bitches. The results obtained indicate that the timing of ovulation bears little relationship to alterations in sexual behaviour. The bitches were killed and reproductive tracts were removed at various intervals after ovulation and ova or embryos were recovered. The embryo stages were assessed visually and some were investigated histologically. Embryonic development, to early blastocyst stage, took place within the oviducts during the first 12 days after ovulation and there was a marked increase in size between the early and late blastocyst. A culture system using cells from the uterine tube supported the development of one 1-cell embryo to the morula stage.

The use of a bovine plasma progesterone ELISA kit to measure progesterone in equine, ovine and canine plasmas

A commerical kit designed to measure the concentration of progesterone in bovine plasma using an enzyme-linked immunosorbent assay (ELISA) has been assessed for measuring progesterone in the plasma of horses, sheep and dogs. Without validation, an immunoassay developed for progesterone in one species should not be used to measure progesterone in the plasma of other species. The kit was assessed by using the criteria of parallelism to a standard curve, the recovery of added progesterone, the correlation with an established radioimmunoassay and the detection of physiological change for each of the species tested. The ELISA kit proved to be acceptable for the analysis of progesterone in the plasma of each species, and in particular for the detection of the low concentrations found during the follicular phase and of the subsequent rise during the luteal phase of the oestrous cycle.