Tibial Tubercle Osteotomy and Medial Patellofemoral Ligament Imbrication for Patellar Instability Due to Trochlear Dysplasia.

BackgroundThe treatment of patellar instability in the setting of trochlear dysplasia is challenging.Purpose/hypothesisThe purpose of this study was to evaluate outcomes for the treatment of recurrent patellar dislocations due to trochlear dysplasia using anteromedialization tibial tubercle osteotomy combined with medial patellofemoral ligament (MPFL) imbrication. We hypothesized that the treatment of patellar instability with tibial tubercle osteotomy and MPFL imbrication would result in improved patient satisfaction and decrease patellar instability events in patients with prior instability and trochlear dysplasia.Study designCase series; Level of evidence, 4.MethodsWe performed a retrospective analysis of patients who underwent MPFL imbrication and concomitant anteromedialization tibial tubercle osteotomy for recurrent patellofemoral instability at a single institution. The minimum follow-up was 1 year. Patient demographic information including age at the time of surgery, sex, body mass index (BMI), tibial tubercle-trochlear groove (TT-TG) distance, and grade of trochlear dysplasia was collected along with relevant operative data. Postoperatively, recurrent dislocation events as well as Knee injury and Osteoarthritis Outcome Score (KOOS), Western Ontario and McMaster Universities Osteoarthritis Index, and Kujala scores were collected, and satisfaction was ascertained by asking patients whether they would undergo the procedure again.ResultsA total of 37 knees from 31 patients (23 female) with a mean follow-up of 3.8 years (range, 1-8.9 years) were included. The mean patient age was 28.8 years (range, 14-45 years), the mean BMI was 24 kg/m2 (range, 20-38 kg/m2), and the mean preoperative TT-TG distance was 18.9 mm (range, 8.4-32.4 mm). Two knees were classified as low-grade trochlear dysplasia (Dejour A) and 35 as high-grade trochlear dysplasia (Dejour B-D). At final follow-up, patients reported mean KOOS subscale scores of 86.5 (Pain), 79.8 (Symptoms), 93.9 (Activities of Daily Living), 74.3 (Sports/Recreation), and 61.9 (Quality of Life), as well as a mean Kujala score of 81.3. Mean patient satisfaction was 8.3 of 10. The majority of knees (86.5%; 32/37) remained stable without recurrent instability after this procedure, while 13.5% (5 knees) suffered a recurrent dislocation, with 2 requiring revision surgery. Eight knees (21.6%) underwent subsequent hardware removal.ConclusionAnteromedialization tibial tubercle osteotomy with MPFL imbrication can improve recurrent patellofemoral instability and provide significant clinical benefit to patients with trochlear dysplasia

Resilience reconciled

Resilience scholarship continues to inspire opaque discourse and competing frameworks often inconsistent with the complexity inherent in social–ecological systems. We contend that competing conceptualizations of resilience are reconcilable, and that the core theory is useful for navigating sustainability challenges. Resilience as a scientific concept exploded in the early 2000s and is now being adopted by a range of disciplines and by a wide diversity of actors, from city planners to networks of global protectedarea managers. Resilience concepts are now integrated within national and international calls for proposals, research initiatives and centres in both the biophysical and social sciences. However, resilience scholarship has encouraged abstract discourse including many new and derivative frameworks aimed at re-conceptualizing resilience. Competing frameworks contribute to a loss of clarity about the original concept and theory of resilience; these frameworks often differ only minimally from each other and, most importantly, are often inconsistent with the complexity inherent in social–ecological systems (SESs). We believe that this is because the concept of resilience has both an attractive simplicity, and a rich underlying complexity, which leaves key aspects open for debate. Despite apparent discrepancies among numerous competing frameworks and the recognition that a diversity of approaches is healthy for scientific progress, we contend that the prevailing definitions of resilience, such as those rooted in ecological stability (for example, recovery, robustness and persistence), are reconcilable under the umbrella of the original theory of ecological resilience (the amount of disturbance needed to cause a regime shift; for example, a clear-water lake changing to a turbid lake)2. Reconciling definitions of resilience is not trivial; our collective understanding and application of resilience has widespread implications for how we, as a society, understand and navigate global change. A view of the Earth as nested SESs — systems of dynamic, linked feedbacks between humans and the biophysical environment (for example, the influence of political economy on landscape shifts and vice versa) — is essential for definitions of resilience to resonate. Currently, resilience is applied as a descriptor, a measure, and a tool for relative analysis of system dynamics. Here we revisit three core uses of the term: resilience as a process, a rate, and an emergent property of SESs3. We reconcile these core uses with ecological resilience2 and provide examples of successful application and growth of the concept

Structure and Metal Binding Properties of ZnuA, a Periplasmic Zinc Transporter from \u3cem\u3eEscherichia coli\u3c/em\u3e

ZnuA is the periplasmic Zn2+-binding protein associated with the high-affinity ATP-binding cassette ZnuABC transporter from Escherichia coli. Although several structures of ZnuA and its homologs have been determined, details regarding metal ion stoichiometry, affinity, and specificity as well as the mechanism of metal uptake and transfer remain unclear. The crystal structures of E. coli ZnuA (Eco-ZnuA) in the apo, Zn2+-bound, and Co2+-bound forms have been determined. ZnZnuA binds at least two metal ions. The first, observed previously in other structures, is coordinated tetrahedrally by Glu59, His60, His143, and His207. Replacement of Zn2+ with Co2+ results in almost identical coordination geometry at this site. The second metal binding site involves His224 and several yet to be identified residues from the His-rich loop that is unique to Zn2+ periplasmic metal binding receptors. Electron paramagnetic resonance and X-ray absorption spectroscopic data on CoZnuA provide additional insight into possible residues involved in this second site. The second site is also detected by metal analysis and circular dichroism (CD) titrations. Eco-ZnuA binds Zn2+ (estimated K d \u3c 20 nM), Co2+, Ni2+, Cu2+, Cu+, and Cd2+, but not Mn2+. Finally, conformational changes upon metal binding observed in the crystal structures together with fluorescence and CD data indicate that only Zn2+ substantially stabilizes ZnuA and might facilitate recognition of ZnuB and subsequent metal transfer

An infrared survey of brightest cluster galaxies: Paper I

We report on an imaging survey with the Spitzer Space Telescope of 62 brightest cluster galaxies with optical line emission. These galaxies are located in the cores of X-ray luminous clusters selected from the ROSAT All-Sky Survey. We find that about half of these sources have a sign of excess infrared emission; 22 objects out of 62 are detected at 70 microns, 18 have 8 to 5.8 micron flux ratios above 1.0 and 28 have 24 to 8 micron flux ratios above 1.0. Altogether 35 of 62 objects in our survey exhibit at least one of these signs of infrared excess. Four galaxies with infrared excesses have a 4.5/3.6 micron flux ratio indicating the presence of hot dust, and/or an unresolved nucleus at 8 microns. Three of these have high measured [OIII](5007A)/Hbeta flux ratios suggesting that these four, Abell 1068, Abell 2146, and Zwicky 2089, and R0821+07, host dusty active galactic nuclei (AGNs). 9 objects (including the four hosting dusty AGNs) have infrared luminosities greater than 10^11 L_sol and so can be classified as luminous infrared galaxies (LIRGs). Excluding the four systems hosting dusty AGNs, the excess mid-infrared emission in the remaining brightest cluster galaxies is likely related to star formation.Comment: accepted for publication in ApJ

Laboratory Focus on Improving the Culture of Biosafety: Statewide Risk Assessment of Clinical Laboratories That Process Specimens for Microbiologic Analysis

The Wisconsin State Laboratory of Hygiene challenged Wisconsin laboratories to examine their biosafety practices and improve their culture of biosafety. One hundred three clinical and public health laboratories completed a questionnaire-based, microbiology-focused biosafety risk assessment. Greater than 96% of the respondents performed activities related to specimen processing, direct microscopic examination, and rapid nonmolecular testing, while approximately 60% performed culture interpretation. Although they are important to the assessment of risk, data specific to patient occupation, symptoms, and travel history were often unavailable to the laboratory and, therefore, less contributory to a microbiology-focused biosafety risk assessment than information on the specimen source and test requisition. Over 88% of the respondents complied with more than three-quarters of the mitigation control measures listed in the survey. Facility assessment revealed that subsets of laboratories that claim biosafety level 1, 2, or 3 status did not possess all of the biosafety elements considered minimally standard for their respective classifications. Many laboratories reported being able to quickly correct the minor deficiencies identified. Task assessment identified deficiencies that trended higher within the general (not microbiology-specific) laboratory for core activities, such as packaging and shipping, direct microscopic examination, and culture modalities solely involving screens for organism growth. For traditional microbiology departments, opportunities for improvement in the cultivation and management of highly infectious agents, such as acid-fast bacilli and systemic fungi, were revealed. These results derived from a survey of a large cohort of small- and large-scale laboratories suggest the necessity for continued microbiology-based understanding of biosafety practices, vigilance toward biosafety, and enforcement of biosafety practices throughout the laboratory setting

Characteristics of Freebase Cocaine Psychosis.

Psychosis was present in 29 percent of cocaine-disordered patients hospitalized in 1985 during an epidemic of freebase cocaine abuse in the Bahamas. Record reviews revealed that a variety of psychotic phenomenologic patterns were present. Prior major mental disorders and increased dosage of cocaine were more common among psychotic than non-psychotic patients. Violent behavior was common among cocaine patients, especially those with psychosis. We conclude that freebase cocaine psychosis is neither rare nor benign

On Bayesian Modelling of the Uncertainties in Palaeoclimate Reconstruction

We outline a model and algorithm to perform inference on the palaeoclimate and palaeoclimate volatility from pollen proxy data. We use a novel multivariate non-linear non-Gaussian state space model consisting of an observation equation linking climate to proxy data and an evolution equation driving climate change over time. The link from climate to proxy data is defined by a pre-calibrated forward model, as developed in Salter-Townshend and Haslett (2012) and Sweeney (2012). Climatic change is represented by a temporally-uncertain Normal-Inverse Gaussian Levy process, being able to capture large jumps in multivariate climate whilst remaining temporally consistent. The pre-calibrated nature of the forward model allows us to cut feedback between the observation and evolution equations and thus integrate out the state variable entirely whilst making minimal simplifying assumptions. A key part of this approach is the creation of mixtures of marginal data posteriors representing the information obtained about climate from each individual time point. Our approach allows for an extremely efficient MCMC algorithm, which we demonstrate with a pollen core from Sluggan Bog, County Antrim, Northern Ireland.Comment: 25 pages, 7 figure

Mass Models and Sunyaev-Zeldovich Effect Predictions for a Flux Limited Sample of 22 Nearby X-Ray Clusters

We define a 90% complete, volume-limited sample of 31 z<0.1 x-ray clusters and present a systematic analysis of public ROSAT PSPC data on 22 of these objects. Our efforts are undertaken in support of the Penn/OVRO SZE survey, and to this end we present predictions for the inverse Compton optical depth towards all 22 of these clusters. We have performed detailed Monte Carlo simulations to understand the effects of the cluster profile uncertainties on the SZE predictions given the OVRO 5.5-meter telescope beam and switching patterns; we find that the profile uncertainties are one of the least significant components of our error budget for SZE-based distance measurements. We also present baryonic masses and baryon mass fractions derived under the assumption of hydrostatic equilibrium for these 22 clusters. The mean baryonic mass fraction within R_500 \sim 500 h^-1 kpc is (7.02 \pm 0.28) x 10^-2 h^-3/2, or (19.8 \pm 0.8) x 10^-2 for h=0.5. We confirm the Allen et al. (1993) claim of an excess absorbing column density towards Abell 478, but do not find similar anomalies in the other 21 clusters in our sample. We also find some evidence for an excess of soft counts in the ROSAT PSPC data. A measurement of H_o using these models and OVRO SZE determinations will be presented in a second paper.Comment: 51 pages, 6 figures included in text. Added comparison of different cosmologies; accepted for publication in Ap