4,571 research outputs found
Platelet-Rich Plasma Injection With Percutaneous Needling for Recalcitrant Lateral Epicondylitis: Comparison of Tenotomy and Fenestration Techniques.
Background: Recalcitrant lateral epicondylitis (LE) is a common debilitating condition, with numerous treatment options of varying success. An injection of platelet-rich plasma (PRP) has been shown to improve LE, although it is unclear whether the method of needling used in conjunction with a PRP injection is of clinical importance.
Purpose: To determine whether percutaneous needle tenotomy is superior to percutaneous needle fenestration when each is combined with a PRP injection for the treatment of recalcitrant LE.
Study Design: Cohort study; Level of evidence, 3.
Methods: A total of 93 patients with recalcitrant LE were treated with a PRP injection and percutaneous needle fenestration (n = 45) or percutaneous needle tenotomy (n = 48) over a 5-year study interval. Preoperative patient data, including visual analog scale for pain (VAS-P), Quick Disabilities of the Arm, Shoulder and Hand (QuickDASH), and Patient-Rated Tennis Elbow Evaluation (PRTEE) scores and grip strength, were obtained from a chart review and compared with postoperative values obtained prospectively. Secondary outcomes included the incidence of complications, need for additional interventions, return to work, and patient satisfaction.
Results: At a mean follow-up of 40 months, significant improvements in VAS-P (mean, -6.1; 95% CI, -6.8 to -5.5; P \u3c .0001), QuickDASH (mean, -46; 95% CI, -52 to -40; P \u3c .0001), and PRTEE (mean, -57; 95% CI, -64 to -50; P \u3c .0001) scores and grip strength (mean, +6.1 kg; 95% CI, 4.9 to 7.3; P \u3c .0001) were observed across the entire study cohort, with no significant differences noted between the fenestration and tenotomy groups. Nine of 45 patients (22%) underwent additional procedures to treat recurrent symptoms in the fenestration group compared with 5 of 48 patients (10%) in the tenotomy group (P = .05). No complications occurred in any patients, and no patients expressed dissatisfaction with their treatment course.
Conclusion: A PRP injection with concomitant percutaneous needling is an effective treatment for recalcitrant LE, with sustained improvements in pain, strength, and function demonstrated at a mean follow-up of longer than 3 years. Although the method of concomitant needling does not appear to have a significant effect on treatment outcomes, more aggressive needle tenotomy is less likely to require conversion to open tenotomy than needle fenestration in the short term to midterm
Amorphous silica nanoparticles aggregate human platelets: potential implications for vascular homeostasis
J Jose Corbalan1,2, Carlos Medina1, Adam Jacoby2, Tadeusz Malinski2, Marek W Radomski11School of Pharmacy and Pharmaceutical Sciences, Faculty of Health Sciences, Panoz Institute, Trinity College Dublin, Ireland; 2Department of Chemistry and Biochemistry, Ohio University, Athens, OH, USABackground: Amorphous silica nanoparticles (SiNP) can be used in medical technologies and other industries leading to human exposure. However, an increased number of studies indicate that this exposure may result in cardiovascular inflammation and damage. A high ratio of nitric oxide to peroxynitrite concentrations ([NO]/[ONOO-]) is crucial for cardiovascular homeostasis and platelet hemostasis. Therefore, we studied the influence of SiNP on the platelet [NO]/[ONOO-] balance and platelet aggregation.Methods: Nanoparticle–platelet interaction was examined using transmission electron microscopy. Electrochemical nanosensors were used to measure the levels of NO and ONOO- released by platelets upon nanoparticle stimulation. Platelet aggregation was studied using light aggregometry, flow cytometry, and phase contrast microscopy.Results: Amorphous SiNP induced NO release from platelets followed by a massive stimulation of ONOO- leading to an unfavorably low [NO]/[ONOO-] ratio. In addition, SiNP induced an upregulation of selectin P expression and glycoprotein IIb/IIIa activation on the platelet surface membrane, and led to platelet aggregation via adenosine diphosphate and matrix metalloproteinase 2-dependent mechanisms. Importantly, all the effects on platelet aggregation were inversely proportional to nanoparticle size.Conclusions: The exposure of platelets to amorphous SiNP induces a critically low [NO]/[ONOO-] ratio leading to platelet aggregation. These findings provide new insights into the pharmacological profile of SiNP in platelets.Keywords: amorphous silica nanoparticles, nanotoxicology, nitric oxide, peroxynitrite, platelet aggregatio
On Pulsar Distance Measurements and their Uncertainties
Accurate distances to pulsars can be used for a variety of studies of the
Galaxy and its electron content. However, most distance measures to pulsars
have been derived from the absorption (or lack thereof) of pulsar emission by
Galactic HI gas, which typically implies that only upper or lower limits on the
pulsar distance are available. We present a critical analysis of all measured
HI distance limits to pulsars and other neutron stars, and translate these
limits into actual distance estimates through a likelihood analysis that
simultaneously corrects for statistical biases. We also apply this analysis to
parallax measurements of pulsars in order to obtain accurate distance estimates
and find that the parallax and HI distance measurements are biased in different
ways, because of differences in the sampled populations. Parallax measurements
typically underestimate a pulsar's distance because of the limited distance to
which this technique works and the consequential strong effect of the Galactic
pulsar distribution (i.e. the original Lutz-Kelker bias), in HI distance
limits, however, the luminosity bias dominates the Lutz-Kelker effect, leading
to overestimated distances because the bright pulsars on which this technique
is applicable are more likely to be nearby given their brightness.Comment: 32 pages, 1 figure, 2 tables; Accepted for publication in the
Astrophysical Journa
Early infant feeding and adiposity risk: from infancy to adulthood
Introduction: Systematic reviews suggest that a longer duration of breast-feeding is associated with a reduction in the risk of later overweight and obesity. Most studies examining breast-feeding in relation to adiposity have not used longitudinal analysis. In our study, we aimed to examine early infant feeding and adiposity risk in a longitudinal cohort from birth to young adulthood using new as well as published data.
Methods: Data from the Western Australian Pregnancy Cohort (Raine) Study in Perth, W.A., Australia, were used to examine associations between breast-feeding and measures of adiposity at 1, 2, 3, 6, 8, 10, 14, 17, and 20 years.
Results: Breast-feeding was measured in a number of ways. Longer breast-feeding (in months) was associated with reductions in weight z-scores between birth and 1 year (β = -0.027; p \u3c 0.001) in the adjusted analysis. At 3 years, breast-feeding for \u3c4 months increased the odds of infants experiencing early rapid growth (OR 2.05; 95% CI 1.43-2.94; p \u3c 0.001). From 1 to 8 years, children breast-fed for ≤4 months compared to ≥12 months had a significantly greater probability of exceeding the 95th percentile of weight. The age at which breast-feeding was stopped and a milk other than breast milk was introduced (introduction of formula milk) played a significant role in the trajectory of the BMI from birth to 14 years; the 4-month cutoff point was consistently associated with a higher BMI trajectory. Introduction of a milk other than breast milk before 6 months compared to at 6 months or later was a risk factor for being overweight or obese at 20 years of age (OR 1.47; 95% CI 1.12-1.93; p = 0.005).
Discussion: Breast-feeding until 6 months of age and beyond should be encouraged and is recommended for protection against increased adiposity in childhood, adolescence, and young adulthood. Adverse long-term effects of early growth acceleration are fundamental in later overweight and obesity. Formula feeding stimulates a higher postnatal growth velocity, whereas breast-feeding promotes slower growth and a reduced likelihood of overweight and obesity. Biological mechanisms underlying the protective effect of breast-feeding against obesity are based on the unique composition and metabolic and physiological responses to human milk
V605 Aquilae: a born again star, a nova or both?
V605 Aquilae is today widely assumed to have been the result of a final
helium shell flash occurring on a single post-asymptotic giant branch star. The
fact that the outbursting star is in the middle of an old planetary nebula and
that the ejecta associated with the outburst is hydrogen deficient supports
this diagnosis. However, the material ejected during that outburst is also
extremely neon rich, suggesting that it derives from an oxygen-neon-magnesium
star, as is the case in the so-called neon novae. We have therefore attempted
to construct a scenario that explains all the observations of the nebula and
its central star, including the ejecta abundances. We find two scenarios that
have the potential to explain the observations, although neither is a perfect
match. The first scenario invokes the merger of a main sequence star and a
massive oxygen-neon-magnesium white dwarf. The second invokes an
oxygen-neon-magnesium classical nova that takes place shortly after a final
helium shell flash. The main drawback of the first scenario is the inability to
determine whether the ejecta would have the observed composition and whether a
merger could result in the observed hydrogen-deficient stellar abundances
observed in the star today. The second scenario is based on better understood
physics, but, through a population synthesis technique, we determine that its
frequency of occurrence should be very low and possibly lower than what is
implied by the number of observed systems. While we could not envisage a
scenario that naturally explains this object, this is the second final flash
star which, upon closer scrutiny, is found to have hydrogen-deficient ejecta
with abnormally high neon abundances. These findings are in stark contrast with
the predictions of the final helium shell flash and beg for an alternative
explanation.Comment: 8 pages, 1 figures, 2 tables, accepted for MNRAS. Better title and
minor corrections compared to previous versio
Discovery of Five Recycled Pulsars in a High Galactic Latitude Survey
We present five recycled pulsars discovered during a 21-cm survey of
approximately 4,150 deg^2 between 15 deg and 30 deg from the galactic plane
using the Parkes radio telescope. One new pulsar, PSR J1528-3146, has a 61 ms
spin period and a massive white dwarf companion. Like many recycled pulsars
with heavy companions, the orbital eccentricity is relatively high (~0.0002),
consistent with evolutionary models that predict less time for circularization.
The four remaining pulsars have short spin periods (3 ms < P < 6 ms); three of
these have probable white dwarf binary companions and one (PSR J2010-1323) is
isolated. PSR J1600-3053 is relatively bright for its dispersion measure of
52.3 pc cm^-3 and promises good timing precision thanks to an intrinsically
narrow feature in its pulse profile, resolvable through coherent dedispersion.
In this survey, the recycled pulsar discovery rate was one per four days of
telescope time or one per 600 deg^2 of sky. The variability of these sources
implies that there are more millisecond pulsars that might be found by
repeating this survey.Comment: 15 pages, 3 figures, accepted for publication in Ap
Analysis of Climate Policy Targets under Uncertainty
Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/).Although policymaking in response to the climate change is essentially a challenge of risk management, most studies of the relation of emissions targets to desired climate outcomes are either deterministic or subject to a limited representation of the underlying uncertainties. Monte Carlo simulation, applied to the MIT Integrated Global System Model (an integrated economic and earth system model of intermediate complexity), is used to analyze the uncertain outcomes that flow from a set of century-scale emissions targets developed originally for a study by the U.S. Climate Change Science Program. Results are shown for atmospheric concentrations, radiative forcing, sea ice cover and temperature change, along with estimates of the odds of achieving particular target levels, and for the global costs of the associated mitigation policy. Comparison with other studies of climate targets are presented as evidence of the value, in understanding the climate challenge, of more complete analysis of uncertainties in human emissions and climate system response.This study received support from the MIT Joint Program on the Science and Policy of Global Change, which is funded by a consortium of government, industry and foundation sponsors
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