Polyetheretherketone as a Biomaterial for Spinal Applications

Threaded lumbar interbody spinal fusion devices (TIBFD) made from titanium have been reported to be 90% effective for single-level lumbar interbody fusion, although radiographic determination of fusion has been intensely debated in the literature. Using blinded radiographic, biomechanic, histologic, and statistical measures, we evaluated a radiolucent polyetheretherketone (PEEK)-threaded interbody fusion device packed with autograft or rhBMP-2 on an absorbable collagen sponge in 13 sheep at 6 months. Radiographic fusion, increased spinal level biomechanical stiffness, and histologic fusion were demonstrated for the PEEK cages filled with autograft or rhBMP-2 on a collagen sponge. No device degradation or wear debris was observed. Only mild chronic inflammation consisting of a few macrophages was observed in peri-implant tissues. Based on these results, the polymeric biomaterial PEEK may be a useful biomaterial for interbody fusion cages due to the polymer\u27s increased radiolucency and decreased stiffness

Bioresorbable Polylactide Interbody Implants in an Ovine Anterior Cervical Discectomy and Fusion Model: Three-Year Results

Study Design. In vivo study of anterior discectomy and fusion using a bioresorbable 70:30 poly(l-lactide-co-d,l-lactide) interbody implant in an ovine model. Objective. To evaluate the efficacy of the polylactide implant to function as an interbody fusion device, and to assess the tissue reaction to the material during the resorption process. Summary of Background Data. The use of polylactide as a cervical interbody implant has several potential advantages when compared with traditional materials. Having an elastic modulus very similar to bone minimizes the potential for stress shielding, and as the material resorbs additional loading is transferred to the developing fusion mass. Although preclinical and clinical studies have demonstrated the suitability of polylactide implants for lumbar interbody fusion, detailed information on cervical anterior cervical discectomy and fusion (ACDF) with polylactide devices is desirable. Methods. Single level ACDF was performed in 8 skeletally mature ewes. Bioresorbable 70:30 poly (l-lactide-co-d,l-lactide) interbody implants packed with autograft were used with single-level metallic plates. Radiographs were made every 3 months up to 1 year, and yearly thereafter. The animals were killed at 6 months (3 animals), 12 months (3 animals), and 36 months (2 animals). In addition to the serial plain radiographs, the specimens were evaluated by nondestructive biomechanical testing and undecalcified histologic analysis. Results. The bioresorbable polylactide implants were effective in achieving interbody fusion. The 6-month animals appeared fused radiographically and biomechanically, whereas histologic sections demonstrated partial fusion (in 3 of 3 animals). Radiographic fusion was confirmed histologically and biomechanically at 12 months (3 of 3 animals) and 36 months (2 of 2 animals). A mild chronic inflammatory response to the resorbing polylactide implant was observed at both 6 months and 12 months. At 36 months, the operative levels were solidly fused and the implants were completely resorbed. No adverse tissue response was observed in any animal at any time period. Conclusion. Interbody fusion was achieved using bioresorbable polylactide implants, with no evidence of implant collapse, extrusion, or adverse tissue response to the material. The use of polylactide as a cervical interbody device appears both safe and effective based on these ACDF animal model results

Auditory In-Vehicle Technologies to Support Older Drivers

OBJECTIVES Population aging, in combination with improved health care and more active lifestyles well into advanced age, have resulted in an increased number of older adults driving more miles than ever before. Unfortunately, these older drivers are over-represented in motor vehicle crashes and crash-related fatalities. Rather than the risk-tasking behaviors observed in young drivers, the collisions of older drivers frequently involve perceptual-cognitive errors. Advanced in-vehicle technologies have the potential to function as sensory-cognitive aids and may offset the negative impact of age-related changes in sensory and cognitive abilities. Collision Avoidance Systems (CASs) function as sensory aids to augment hazard detection capabilities, and therefore may be of particular benefit to older drivers. Navigation aids can offset the working memory requirements of wayfinding, and auditory guidance directions may reduce the visual demands of searching for street signs and reading maps. However, these advanced systems also have the potential to increase the information processing demands of the driving task or distract drivers, particularly if they are not designed in accordance with the sensory and perceptual capabilities of older adults. A series of experiments aimed at examining the impact of sensory-cognitive characteristics of auditory navigational aids on driver wayfinding, performance on a visual peripheral detection task, and neurophysiological, behavioral and subjective indices of driver mental workload and performance were conducted. METHODS Results of two investigations will be discussed. The first investigation examined the impact of amplitude level on working memory. Older adults frequently exhibit reduced complex working memory span. However, recent evidence indicates that increasing a sound’s amplitude increases its duration in echoic memory (Baldwin, in press). Based on these findings, we hypothesized that increasing the amplitude of verbal material would improve working memory efficiency. RESULTS In support of this hypothesis, a strong positive correlation between the amplitude level at which the verbal material was presented and complex working memory span as measured by a version of Daneman and Carpenter’s (1980) Listening span task was observed. This positive relationship OBJECTIVES Population aging, in combination with improved health care and more active lifestyles well into advanced age, have resulted in an increased number of older adults driving more miles than ever before. Unfortunately, these older drivers are over-represented in motor vehicle crashes and crash-related fatalities. Rather than the risk-tasking behaviors observed in young drivers, the collisions of older drivers frequently involve perceptual-cognitive errors. Advanced in-vehicle technologies have the potential to function as sensory-cognitive aids and may offset the negative impact of age-related changes in sensory and cognitive abilities. Collision Avoidance Systems (CASs) function as sensory aids to augment hazard detection capabilities, and therefore may be of particular benefit to older drivers. Navigation aids can offset the working memory requirements of wayfinding, and auditory guidance directions may reduce the visual demands of searching for street signs and reading maps. However, these advanced systems also have the potential to increase the information processing demands of the driving task or distract drivers, particularly if they are not designed in accordance with the sensory and perceptual capabilities of older adults. A series of experiments aimed at examining the impact of sensory-cognitive characteristics of auditory navigational aids on driver wayfinding, performance on a visual peripheral detection task, and neurophysiological, behavioral and subjective indices of driver mental workload and performance were conducted. METHODS Results of two investigations will be discussed. The first investigation examined the impact of amplitude level on working memory. Older adults frequently exhibit reduced complex working memory span. However, recent evidence indicates that increasing a sound’s amplitude increases its duration in echoic memory (Baldwin, in press). Based on these findings, we hypothesized that increasing the amplitude of verbal material would improve working memory efficiency. RESULTS In support of this hypothesis, a strong positive correlation between the amplitude level at which the verbal material was presented and complex working memory span as measured by a version of Daneman and Carpenter’s (1980) Listening span task was observed. This positive relationshi

The Next 10 Years in Atrial Fibrillation

Predicting future advancements in arrhythmia management – specifically AF – with any certainty is impossible. The clinical approach to AF has changed markedly since the turn of the century in ways that could never have been foreseen, but the current methods of identification and treatment remain far from perfect. Over the next decade we expect significant continued progress in AF management. However, if asked to forecast the future, we consider it wise to predict advancements in the nearer term. We believe there will be widespread expansion in digital health and mobile devices, altering the way we detect and monitor the arrhythmia. We expect substantial growth in advanced MRI to aid in early detection, evaluation, and possibly non-invasive treatment of AF substrate. We imagine there will be increasing focus on individual populations to identify at-risk groups and personalize early management. We also anticipate improvement in anticoagulation employment and left atrial appendage modification. Finally, recognizing the benefit of improvement in modifiable risk factors such as mandatory tobacco cessation and weight loss in obese patients, we predict that reimbursement will be dependent on successfully addressing modifiable risk. For now, several questions remain unanswered, and while no one can predict the next 10 years in AF, there is, without doubt, an abundance of opportunity

Cigarette smoke exposure mediated generation of Platelet-activating factor agonists induces systemic immunosuppression

poster abstractThe ubiquitous environmental pollutant cigarette smoke (CS) is known to exert immodulatory effects. CS also acts as a potent pro-oxidative stressor. Several studies including ours have characterized the importance of various pro-oxidative stressors including UVB to inhibit host immunity and an importance of the platelet-activating factor (1-alkyl-2-acetyl-glycerophosphocholine; PAF), a potent lipid mediator in this process. PAF is produced enzymatically in a tightly-controlled process. In addition, oxidative stressors can act directly on glycerophosphocholines (GPC) to produce oxidized GPC which are potent PAF-R agonists. The present studies employed model systems consisting of PAF-receptor (PAF-R)-expressing (KBP) and–deficient (KBM) cells and mice (wild type [WT] and Pafr-/-) to determine whether CS exposure could generate PAF-R agonists in blood and whether it could suppress contact hypersensitivity reactions in a PAF-R-dependent manner. We show that lipid extracts derived from the blood of CS-treated WT mice resulted in immediate intracellular calcium (Ca2+2+mice. This inhibitory effect of CS in WT mice were similar to those induced by a PAF-R agonist, CPAF or histamine. Furthermore, this inhibition of CHS by CS in WT mice was blocked by antioxidants vitamin C and N-acetyl cysteine. These findings indicate that CS exposure induces systemic immunosuppression in a PAF-R-dependent manner. These studies provide the first evidence that the pro-oxidative stressor CS can modulate cutaneous immunity via the generation of PAF agonists through lipid oxidation.) mobilization response only in KBP cells. However, no Camobilization response was detected with lipid extracts from non-smoked (sham) mice both in KBP and KBM cells. In addition, lipid extracts only from CS-treated mice induced an increase in IL-8 secretion in KBP cells indicating that CS generates systemic PAF-R agonists. CS exposure also inhibited contact hypersensitivity to the allergen dinitrofluorobenzene (DNFB) selectively in WT but not inPafr-/

Predicting the response of a submillimeter bolometer to cosmic rays

Bolometers designed to detect. submillimeter radiation also respond to cosmic, gamma, and x rays. Because detectors cannot be fully shielded from such energy sources, it is necessary to understand the effect of a photon or cosmic-ray particle being absorbed. The resulting signal (known as a glitch) can then be removed from raw data. We present measurements using an Americium-241 gamma radiation source to irradiate a prototype bolometer for the High Frequency Instrument in the Planck Surveyor satellite. Our measurements showed no variation in response depending on where the radiation was absorbed, demonstrating that the bolometer absorber and thermistor thermalize quickly. The bolometer has previously been fully characterized both electrically and optically. We find that using optically measured time constants underestimates the time taken for the detector to recover from a radiation absorption event. However, a full thermal model for the bolometer, with parameters taken from electrical and optical measurements, provides accurate time constants. Slight deviations from the model were seen at high energies; these can be accounted for by use of an extended model

Modeling Multi-Wavelength Stellar Astrometry. II. Determining Absolute Inclinations, Gravity Darkening Coefficients, and Spot Parameters of Single Stars with SIM Lite

We present a novel technique to determine the absolute inclination of single stars using multi-wavelength sub-milliarcsecond astrometry. The technique exploits the effect of gravity darkening, which causes a wavelength-dependent astrometric displacement parallel to a star's projected rotation axis. We find this effect is clearly detectable using SIM Lite for various giant stars and rapid rotators, and present detailed models for multiple systems using the REFLUX code. We also explore the multi-wavelength astrometric reflex motion induced by spots on single stars. We find that it should be possible to determine spot size, relative temperature, and some positional information for both giant and nearby main-sequence stars utilizing multi-wavelength SIM Lite data. This data will be extremely useful in stellar and exoplanet astrophysics, as well as supporting the primary SIM Lite mission through proper multi-wavelength calibration of the giant star astrometric reference frame, and reduction of noise introduced by starspots when searching for extrasolar planets.Comment: 8 pages, 7 figures, 4 tables. Accepted for publication in the Astrophysical Journa

Identifying nonalcoholic fatty liver disease patients with active fibrosis by measuring extracellular matrix remodeling rates in tissue and blood.

Excess collagen synthesis (fibrogenesis) in the liver plays a causal role in the progression of nonalcoholic fatty liver disease (NAFLD). Methods are needed to identify patients with more rapidly progressing disease and to demonstrate early response to treatment. We describe here a novel method to quantify hepatic fibrogenesis flux rates both directly in liver tissue and noninvasively in blood. Twenty-one patients with suspected NAFLD ingested heavy water (2 H2 O, 50-mL aliquots) two to three times daily for 3-5 weeks prior to a clinically indicated liver biopsy. Liver collagen fractional synthesis rate (FSR) and plasma lumican FSR were measured based on 2 H labeling using tandem mass spectrometry. Patients were classified by histology for fibrosis stage (F0-F4) and as having nonalcoholic fatty liver or nonalcoholic steatohepatitis (NASH). Magnetic resonance elastography measurements of liver stiffness were also performed. Hepatic collagen FSR in NAFLD increased with advancing disease stage (e.g., higher in NASH than nonalcoholic fatty liver, positive correlation with fibrosis score and liver stiffness) and correlated with hemoglobin A1C. In addition, plasma lumican FSR demonstrated a significant correlation with hepatic collagen FSR.ConclusionUsing a well-characterized cohort of patients with biopsy-proven NAFLD, this study demonstrates that hepatic scar in NASH is actively remodeled even in advanced fibrosis, a disease that is generally regarded as static and slowly progressive. Moreover, hepatic collagen FSR correlates with established risks for fibrotic disease progression in NASH, and plasma lumican FSR correlates with hepatic collagen FSR, suggesting applications as direct or surrogate markers, respectively, of hepatic fibrogenesis in humans. (Hepatology 2017;65:78-88)

Oiling Of The Continental Shelf And Coastal Marshes Over Eight Years After The 2010 Deepwater Horizon Oil Spill

We measured the temporal and spatial trajectory of oiling from the April, 2010, Deepwater Horizon oil spill in water from Louisiana\u27s continental shelf, the estuarine waters of Barataria Bay, and in coastal marsh sediments. The concentrations of 28 target alkanes and 43 target polycyclic aromatic hydrocarbons were determined in water samples collected on 10 offshore cruises, in 19 water samples collected monthly one km offshore at 13 inshore stations in 2010 and 2013, and in 16-60 surficial marsh sediment samples collected on each of 26 trips. The concentration of total aromatics in offshore waters peaked in late summer, 2010, at 100 times above the May, 2010 values, which were already slightly contaminated. There were no differences in surface or bottom water samples. The concentration of total aromatics declined at a rate of 73% y(-1) to 1/1000th of the May 2010 values by summer 2016. The concentrations inside the estuary were proportional to those one km offshore, but were 10-30% lower. The oil concentrations in sediments were initially different at 1 and 10 m distance into the marsh, but became equal after 2 years. Thus, the distinction between oiled and unoiled sites became blurred, if not non-existent then, and oiling had spread over an area wider than was visible initially. The concentrations of oil in sediments were 100-1000 times above the May 2010 values, and dropped to 10 times higher after 8 years, thereafter, demonstrating a long-term contamination by oil or oil residues that will remain for decades. The chemical signature of the oil residues offshore compared to in the marsh reflects the more aerobic offshore conditions and water-soluble tendencies of the dissolved components, whereas the anaerobic marsh sediments will retain the heavier molecular components for a long time, and have a consequential effect on the ecosystems. (C) 2019 The Authors. Published by Elsevier Ltd

Expanding Paramedicine in the Community (EPIC): study protocol for a randomized controlled trial.

BackgroundThe incidence of chronic diseases, including diabetes mellitus (DM), heart failure (HF) and chronic obstructive pulmonary disease (COPD) is on the rise. The existing health care system must evolve to meet the growing needs of patients with these chronic diseases and reduce the strain on both acute care and hospital-based health care resources. Paramedics are an allied health care resource consisting of highly-trained practitioners who are comfortable working independently and in collaboration with other resources in the out-of-hospital setting. Expanding the paramedic's scope of practice to include community-based care may decrease the utilization of acute care and hospital-based health care resources by patients with chronic disease.Methods/designThis will be a pragmatic, randomized controlled trial comparing a community paramedic intervention to standard of care for patients with one of three chronic diseases. The objective of the trial is to determine whether community paramedics conducting regular home visits, including health assessments and evidence-based treatments, in partnership with primary care physicians and other community based resources, will decrease the rate of hospitalization and emergency department use for patients with DM, HF and COPD. The primary outcome measure will be the rate of hospitalization at one year. Secondary outcomes will include measures of health system utilization, overall health status, and cost-effectiveness of the intervention over the same time period. Outcome measures will be assessed using both Poisson regression and negative binomial regression analyses to assess the primary outcome.DiscussionThe results of this study will be used to inform decisions around the implementation of community paramedic programs. If successful in preventing hospitalizations, it has the ability to be scaled up to other regions, both nationally and internationally. The methods described in this paper will serve as a basis for future work related to this study.Trial registrationClinicalTrials.gov: NCT02034045. Date: 9 January 2014