Total Joint Arthroplasty in the Patient with Inflammatory Arthritis: A Review.

Inflammatory arthritis is a family of conditions including rheumatoid arthritis, juvenile inflammatory arthritis, and spondyloarthropathies affecting both the large and small joints. Total joint arthroplasty is commonly used for surgical management of end-stage disease. Preoperative and postoperative considerations as well as perioperative medical management and intraoperative treatment of patients with inflammatory arthritis undergoing total joint arthroplasty are reviewed. Although individualized, multidisciplinary approaches to treatment are necessary due to the complex nature of the disease and the varying levels of severity, patients generally have favorable outcomes with respect to pain scores and functional outcomes.

Contrasting Views of the Electric Double Layer in Electrochemical CO2 Reduction: Continuum Models vs Molecular Dynamics.

In the field of electrochemical CO2 reduction, both continuum models and molecular dynamics (MD) models have been used to understand the electric double layer (EDL). MD often focuses on the region within a few nm of the electrode, while continuum models can span up to the device level (cm). Still, both methods model the EDL, and for a cohesive picture of the CO2 electrolysis system, the two methods should agree in the regions where they overlap length scales. To this end, we make a direct comparison between state-of-the-art continuum models and classical MD simulations under the conditions of CO2 reduction on a Ag electrode. For continuum modeling, this includes the Poisson-Nernst-Planck formulation with steric (finite ion size) effects, and in MD the electrode is modeled with the constant potential method. The comparison yields numerous differences between the two modeling methods. MD shows cations forming two adsorbed layers, including a fully hydrated outer layer and a partial hydration layer closer to the electrode surface. The strength of the inner adsorbed layer increases with cation size (Li+ < Na+ < K+ < Cs+) and with more negative applied potentials. Continuum models that include steric effects predict CO2 to be mostly excluded within 1 nm of the cathode due to tightly packed cations, yet we find little evidence to support these predictions from the MD results. In fact, MD shows that the concentration of CO2 increases within a few Å of the cathode surface due to interactions with the Ag electrode, a factor not included in continuum models. The EDL capacitance is computed from the MD results, showing values in the range of 7-9 µF cm-2, irrespective of the electrolyte concentration, cation identity, or applied potential. The direct comparison between the two modeling methods is meant to show the areas of agreement and disagreement between the two views of the EDL, so as to improve and better align these models.

Force Production Measurements During a Supine Medicine Ball Throw: a Reliability and Correlation Study.

OBJECTIVES: This study aimed to examine the reliability of supine medicine ball throw peak force and rate of force development (RFD) measurements. A secondary aim was to investigate the correlations between these measurements and vertical jump height. METHODS: Twenty young women (21±3 years) reported for experimental testing on two different occasions. Supine medicine ball throw assessments were performed during each testing session to assess peak force, RFDmax, and RFD at specific percentages of peak force (RFD30% and RFD40-80%). Vertical jumps were performed on a jump mat. The jump mat measured vertical jump height based on flight time. RESULTS: Good intraclass correlation coefficients (≥0.82) and coefficients of variation (≤14.0%) were observed between sessions for peak force, RFDmax, and RFD40-80%, but not for RFD30% (0.55, 27.2%). There were significant correlations between jump height and peak force (r=0.483, P=0.031), RFDmax (r=0.484, P=0.031), and RFD40-80% (r=0.491, P=0.028). There was no significant correlation between jump height and RFD30% (r=0.359, P=0.120). CONCLUSIONS: Our results showed that supine medicine ball throw peak force, RFDmax, and RFD40-80% were reliable measures for assessing upper-body explosive strength in young adults. These measurements were significantly associated with vertical jump height and therefore, may be effective predictors of one's athletic ability.

Hand Surgeon Posture: An Evaluation and Factors That Affect It.

Objective: Approximately 68% of orthopaedic surgeons report occupational related musculoskeletal pain, with back pain being the most common. Poor posture while operating has been proven to contribute to these high rates of musculoskeletal pain. There is little research regarding intraoperative surgeon posture within the field of hand and upper extremity surgery. This prospective study aims to investigate and analyze hand surgeon posture in the operating room. Methods: Posture of three hand surgeons was recorded using the UPRIGHT GO posture tracking device while performing a prospective series of 223 hand and upper extremity surgeries. This device reports posture in terms of overall percentage of time spent slouched versus upright. For this cohort of 223 cases, data were collected including surgical procedure, whether the surgery was performed in a seated or standing position, whether or not loupes were worn during the procedure, and if the surgeon was the primary or assistant surgeon. These data were then analyzed to look for any contributing factors to poor posture. Results: The three hand surgeons in this study spent an average of 40.3% of their time slouched while operating. The average percentage of time slouched was significantly greater with the use of loupes versus no loupes. Additionally, mean time slouching was slightly increased when the surgeon was seated and also when the surgeon was acting as the assistant surgeon. Conclusion: The three orthopaedic hand surgeons in our study spent a significant portion of their operative time slouched. The main variable associated with a significant risk of poor surgical posture was wearing loupes. Slight increases in slouching were seen with operating while seated and as the assistant surgeon. Surgeon awareness of these variables, as well as techniques to improve surgeon posture, should be developed in order to help contribute to better surgeon posture within the field of hand surgery.

Is mild dehydration a risk for progression of childhood chronic kidney disease?

Children with chronic kidney disease (CKD) can have an inherent vulnerability to dehydration. Younger children are unable to freely access water, and CKD aetiology and stage can associate with reduced kidney concentrating capacity, which can also impact risk. This article aims to review the risk factors and consequences of mild dehydration and underhydration in CKD, with a particular focus on evidence for risk of CKD progression. We discuss that assessment of dehydration in the CKD population is more challenging than in the healthy population, thus complicating the definition of adequate hydration and clinical research in this field. We review pathophysiologic studies that suggest mild dehydration and underhydration may cause hyperfiltration injury and impact renal function, with arginine vasopressin as a key mediator. Randomised controlled trials in adults have not shown an impact of improved hydration in CKD outcomes, but more vulnerable populations with baseline low fluid intake or poor kidney concentrating capacity need to be studied. There is little published data on the frequency of dehydration, and risk of complications, acute or chronic, in children with CKD. Despite conflicting evidence and the need for more research, we propose that paediatric CKD management should routinely include an assessment of individual dehydration risk along with a treatment plan, and we provide a framework that could be used in outpatient settings.

MRI order appropriateness for chronic neck pain: Comparison of ordering practices and treatment outcomes for primary care physicians and specialists.

Chronic neck pain is a common reason for doctor visits in the United States. This diagnosis can be evaluated through patient history, physical examination, and judicious use of radiographs. However, possible inappropriate magnetic resonance imaging (MRI) ordering persists. We hypothesized that no difference in ordering practices, ordering appropriateness, and subsequent intervention would be appreciated regarding physician specialty, location, patient characteristics, and history and physical exam findings. A multisite retrospective review of cervical spine MRI between 2014 and 2018 was performed. A total of 332 patients were included. Statistical analysis was used to assess MRI order appropriateness, detail of history and physical exam findings, and intervention decision-making among different specialties. If significant differences were found, multiple linear regression was performed to evaluate the association of MRI order appropriateness regarding physician specialty, location, patient characteristics and history, and physical exam findings. The significance level for all tests was set at <0.05 Orthopedic surgeons ordered MRIs most appropriately with an average American College of Radiology (ACR) score of 8.4 (p < 0.005). Orthopedic surgeons had more comprehensive physical exams as compared to the remaining specialties. The decision for intervention did not vary by physician specialty or ACR score, except for patients of pain medicine physicians who received pain management (p = 0.000). Orthopedic surgeons utilize MRI most appropriately and have more comprehensive physical exams. These findings suggest a need for increased physician education on what indicates an appropriate MRI order to improve the use of resources and further protect patient risk-benefit profiles. Further research elucidating factors to minimize negative findings in "appropriate" MRIs is indicated. Clinical significance: More detailed physical exams may lead to more appropriately ordered MRIs, subsequently resulting in surgery or procedures being performed when appropriately indicated. This suggests the need for increased physician education on when MRI ordering is appropriate for chronic neck pain to improve the use of resources and further protect patient risk-benefit profiles.

Spinal Versus General Anesthesia for Outpatient Total Hip and Knee Arthroplasty in the Ambulatory Surgery Center: A Matched-Cohort Study.

BACKGROUND: Spinal anesthesia is the predominant regimen in outpatient total joint arthroplasty (TJA), but induction often is unsuccessful, unobtainable, or against patient preference. We compared outcomes of same-day discharge (SDD) TJA with spinal versus general anesthesia in a free-standing ambulatory surgery center (ASC). METHODS: We took 105 general anesthesia TJA and one-to-one nearest-neighbor matched them to 105 spinal anesthesia TJA over 7 years at 1 ASC. The rate of successful SDD, minutes to discharge, postoperative pain and nausea, and 90-day complications were compared. Postanesthesia care unit outcomes were additionally stratified by spinal anesthetic (mepivacaine versus bupivacaine). RESULTS: All spinal anesthetic patients underwent SDD compared with 103 (98%) general anesthetic patients (P = .498). Mepivacaine spinal anesthesia patients spent the fewest minutes in postanesthesia care unit prior to discharge from the facility (206), followed by general anesthesia (227), and bupivacaine spinal anesthesia (291; P < .001). General anesthesia patients had the highest levels of pain at 1 hour (5.2 versus 1.5 versus 1.5) and 2 hours (3.2 versus 2.0 versus 1.3) postoperatively, and rates of nausea (48 versus 22 versus 28%) compared with mepivacaine and bupivacaine spinal anesthesia, respectively. The 90-day complications (6 versus 7), admissions (1 versus 3), and reoperations (5 versus 2) were similar among spinal and general anesthesia, respectively (P ≥ .445). CONCLUSIONS: Both spinal and general anesthesia led to reliable SDD with similar 90-day complication rates. General anesthesia facilitated faster discharge from the ASC compared with bupivacaine spinal anesthesia but led to higher levels of pain and incidence of nausea postoperatively. LEVEL OF EVIDENCE: Level 3, Retrospective Cohort Comparison.

Rare Guest-Induced Electrical Conductivity of Zn-Porphyrin Metallacage Inclusion Complexes Featuring π-Donor/Acceptor/Donor Stacks.

Charge-transfer (CT) interactions between co-facially aligned π-donor/acceptor (π-D/A) arrays engender unique optical and electronic properties that could benefit (supra)molecular electronics and energy technologies. Herein, we demonstrate that a tetragonal prismatic metal-organic cage (MOC18+) having two parallel π-donor tetrakis(4-carboxyphenyl)-Zn-porphyrin (ZnTCPP) faces selectively intercalate planar π-acceptor guests, such as hexaazatriphenylene hexacarbonitrile (HATHCN), hexacyanotriphenylene (HCTP), and napthanelediimide (NDI) derivatives, forming 1:1 πA@MOC18+ inclusion complexes featuring supramolecular π-D/A/D triads. The π-acidity of intercalated π-acceptors (HATHCN ≫ HCTP ≈ NDIs) dictated the nature and strength of their interactions with the ZnTCPP faces, which in turn influenced the binding affinities (Ka) and optical and electronic properties of corresponding πA@MOC18+ inclusion complexes. Owing to its strongest CT interaction with ZnTCPP faces, the most π-acidic HATHCN guest enjoyed the largest Ka (5 × 106 M-1), competitively displaced weaker π-acceptors from the MOC18+ cavity, and generated the highest electrical conductivity (2.1 × 10-6 S/m) among the πA@MOC18+ inclusion complexes. This work demonstrates a unique through-space charge transport capability of πA@MOC18+ inclusion complexes featuring supramolecular π-D/A/D triads, which generated tunable electrical conductivity, which is a rare but much coveted electronic property of such supramolecular assemblies that could further expand their utility in future technologies.

Pathways to enhance electrochemical CO2 reduction identified through direct pore-level modeling.

Electrochemical conversion of CO2 to fuels and valuable products is one pathway to reduce CO2 emissions. Electrolyzers using gas diffusion electrodes (GDEs) show much higher current densities than aqueous phase electrolyzers, yet models for multi-physical transport remain relatively undeveloped, often relying on volume-averaged approximations. Many physical phenomena interact inside the GDE, which is a multiphase environment (gaseous reactants and products, liquid electrolyte, and solid catalyst), and a multiscale problem, where "pore-scale" phenomena affect observations at the "macro-scale". We present a direct (not volume-averaged) pore-level transport model featuring a liquid electrolyte domain and a gaseous domain coupled at the liquid-gas interface. Transport is resolved, in 2D, around individual nanoparticles comprising the catalyst layer, including the electric double layer and steric effects. The GDE behavior at the pore-level is studied in detail under various idealized catalyst geometries configurations, showing how the catalyst layer thickness, roughness, and liquid wetting behavior all contribute to (or restrict) the transport necessary for CO2 reduction. The analysis identifies several pathways to enhance GDE performance, opening the possibility for increasing the current density by an order of magnitude or more. The results also suggest that the typical liquid-gas interface in the GDE of experimental demonstrations form a filled front rather than a wetting film, the electrochemical reaction is not taking place at a triple-phase boundary but rather a thicker zone around the triple-phase boundary, the solubility reduction at high electrolyte concentrations is an important contributor to transport limitations, and there is considerable heterogeneity in the use of the catalyst. The model allows unprecedented visualization of the transport dynamics inside the GDE across multiple length scales, making it a key step forward on the path to understanding and enhancing GDEs for electrochemical CO2 reduction.

Reliability of handgrip strength measurements and their relationship with muscle power.

BACKGROUND: Handgrip peak force and rate of force development (RFD) have been shown to be useful measurements at characterizing the strength capacities of numerous muscle groups, including those of the lower extremities. However, the reliability of these measurements and their relationship with peak muscle power remain uncertain. We aimed to examine the reliability of handgrip peak force and RFD measurements. A secondary aim was to determine if these measurements are correlated with peak muscle power. METHODS: Twenty young women (21±3 years) reported for testing on two different occasions. Handgrip contractions were performed during each testing session to assess peak force, peak RFD, and RFD at 0-100 (RFD100) and 0-200 (RFD200) ms. Peak power was assessed from a vertical jump test. RESULTS: Handgrip peak force and RFD measurements were highly consistent between sessions, with intraclass correlation coefficients of 0.89-0.92 and coefficients of variation of 4.9-6.4%. There were significant correlations between peak power and handgrip peak force (r=0.612, P=0.004), peak RFD (r=0.731, P<0.001), RFD100 (r=0.671, P=0.001), and RFD200 (r=0.701, P=0.001). Stepwise multiple regression analysis indicated that handgrip peak RFD was the single best predictor of peak power (R2=0.535). CONCLUSIONS: Our results showed that handgrip peak force and RFD measurements are highly reliable and significantly associated with performance during a vertical jump test. The output from our multiple regression analysis suggests that handgrip peak RFD may be an effective predictor of muscle power.

Percutaneous thrombectomy of upper extremity and thoracic central veins using Inari ClotTriever System: Experience in 14 patients.

Objective: In the present report, we have described the technical and clinical outcomes of percutaneous thrombectomy in the deep veins of the upper extremity and thorax using the ClotTriever system (Inari Medical, Irvine, CA). Methods: Fourteen patients with symptomatic deep venous occlusive disease in the upper extremity deep veins and thoracic central veins who had undergone thrombectomy using the ClotTriever system between October 2020 and January 2022 were reviewed. The technical results, adverse events, imaging follow-up data, and clinical outcomes were recorded. Results: Fourteen patients (seven men and seven women; mean age, 53.6 ± 13.3 years) constituted the study cohort. Of the 14 patients, 9 (64.3%) had had DVT due to intravascular invasion or external compression from known malignancy, 2 (14.3%) had had infected thrombi and/or vegetation due to Staphylococcus aureus refractory to intravenous antibiotic therapy, and 3 (21.4%) had had a benign etiology for thrombus formation. The presenting symptoms included upper extremity and/or facial swelling (n = 14), upper extremity pain (n = 6), fever (n = 2), and dyspnea (n = 1). Thrombectomy with the ClotTriever system was successfully completed in all 14 patients. Seven patients (50.0%) had required additional venous stent reconstruction after thrombectomy to address the underlying stenosis. No major adverse events were noted. All the patients had experienced resolution of the presenting symptoms. Conclusions: For the management of symptomatic deep venous occlusive disease of the upper extremity deep veins and thoracic central veins, thrombectomy using the ClotTriever system was feasible with excellent technical and clinical success.

Effect of treatment adherence on the association between sex and unfavourable treatment outcomes among tuberculosis patients in Puducherry, India: a mediation analysis.

BACKGROUND: A better understanding of the complex interplay between risk factors of tuberculosis (TB) is essential. This study was part of the Regional Prospective Observational Research for Tuberculosis (RePORT) India consortium and includes newly diagnosed TB patients in Puducherry between 2014 and 2018. We employed mediation analysis to identify the effect of treatment adherence on association between sex and unfavourable TB treatment outcomes. METHODS: Required demographic and treatment-related variables were extracted from the RePORT India consortium database and causal mediation analysis using parametric regression models was done. RESULTS: Of the 712 TB patients, ~87 (12.2%) had unfavourable TB treatment outcomes. Total effect of male sex was significantly associated with the unfavourable TB treatment outcomes [adjusted odds ratio (aOR) = 2.48; 95% confidence interval (CI): 1.11-5.55]. However, the overall association between male sex and TB treatment outcomes was dominated by the indirect pathway, as the direct pathway does not show significant association (aOR = 1.67; 95% CI: 0.75-3.75), while the indirect pathway shows significantly higher odds of TB treatment outcomes (aOR = 1.48; 95% CI:1.27-1.73), indicating complete mediation by the treatment adherence. CONCLUSIONS: The study has shown a complete mediation of sexes through TB treatment adherence for unfavourable treatment outcomes. Developing of treatment strategies require better understanding between the biological and social factors related to TB.

Total water intake guidelines are sufficient for optimal hydration in United States adults.

PURPOSE: Recent studies suggest that 24-h urine osmolality (UOsm) for optimal water intake should be maintained < 500 mmol·kg-1. The purpose of this study was to determine the total water intake (TWI) requirement for healthy adults to maintain optimal hydration as indicated by 24-h urine osmolality < 500 mmol·kg-1. METHODS: Twenty-four-hour UOsm was assessed in 49 men and 50 women residing in the United States (age: 41 ± 14 y, body mass index: 26.3 ± 5.2 kg·m-2). TWI was assessed from 7-day water turnover, using a dilution of deuterium oxide, corrected for metabolic water production. The diagnostic accuracy of TWI to identify UOsm < 500 mmol·kg-1 was evaluated using receiver operating characteristic (ROC) analysis in men and women separately. RESULTS: Twenty-four-hour UOsm was 482 ± 229 and 346 ± 182 mmol·kg-1 and TWI was 3.57 ± 1.10 L·d-1 and 3.20 ± 1.27 L·d-1 in men and women, respectively. ROC analysis for TWI detecting 24-h UOsm < 500 mmol·kg-1 in men yielded an area under the curve (AUC) of 77.4% with sensitivity, specificity, and threshold values of 83.3%, 64.5%, and 3.39 L·d-1, respectively. The AUC was 82.4% in women with sensitivity, specificity, and threshold values of 85.7%, 72.1%, and 2.61 L·d-1. CONCLUSION: Considering threshold values in men and women of 3.4 L·d-1 and 2.6 L·d-1, respectively, maintaining TWI in line with National Academy of Medicine guidelines of 3.7 L·d-1 in men and 2.7 L·d-1 in women should be sufficient for most individuals in the United States to maintain 24-h UOsm < 500 mmol·kg-1.

Age-related differences in vertical jump height and handgrip strength measurements.

PURPOSE: This study aimed to examine the effects of age on vertical jump height and handgrip strength measurements in women. A secondary aim was to investigate the correlations between vertical jump height and handgrip strength. METHODS: Twenty young (21.5 ± 2.8 years) and twenty older (67.0 ± 5.5 years) healthy women participated in this study. Handgrip contractions were used to assess strength measurements of peak force and rate of force development at different time intervals. Vertical jumps were performed on a jump mat. The jump mat measured vertical jump height based on flight time. RESULTS: The older women had lower vertical jump height (P < 0.001) and handgrip peak force (P = 0.028) and rate of force development values (P = 0.003-0.016) than the younger women. A larger difference was observed between the groups for vertical jump height (41%) than handgrip peak force and rate of force development (12-17%). Of all the strength measurements, handgrip rate of force development at 200 ms in the young (r = 0.502, P = 0.024) and older (r = 0.446, P = 0.049) women exhibited the strongest correlation with vertical jump height. CONCLUSIONS: This investigation showed significantly lower vertical jump height and handgrip peak force and rate of force development values in older compared to younger women. Interestingly, the difference between age groups was larger for jump height than handgrip peak force and rate of force development. This suggests that vertical jump performance may be more severely affected by age than handgrip strength characteristics.

An explanation for unexpected population crashes in a constant environment.

Unexpected population crashes are an important feature of natural systems, yet many observed crashes have not been explained. Two difficulties in explaining population crashes are their relative rarity and the multi-causal nature of ecological systems. We approach this issue with experimental microcosms, with large numbers of replicates of red flour beetle populations (Tribolium castaneum). We determined that population crashes are caused by an interaction between stochasticity and successive episodes of density dependence: demographic stochasticity in oviposition rates occasionally produces a high density of eggs; so high that there are insufficient flour resources for subsequent larvae. This mechanism can explain unexpected population crashes in more general settings: stochasticity 'pushes' population into a regime where density dependence is severely overcompensatory. The interaction between nonlinearity and stochasticity also produces chaotic population dynamics and a double-humped one-generation population map, suggesting further possibilities for unexpected behaviour in a range of systems. We discuss the generality of our proposed mechanism, which could potentially account for previously inexplicable population crashes.

Development of a Three-Dimensional Multi-Modal Perfusion-Thermal Electrode System for Complete Tumor Eradication.

Background: Residual viable tumor cells after ablation at the tumor periphery serve as the source for tumor recurrence, leading to treatment failure. Purpose: To develop a novel three-dimensional (3D) multi-modal perfusion-thermal electrode system completely eradicating medium-to-large malignancies. Materials and Methods: This study included five steps: (i) design of the new system; (ii) production of the new system; (iii) ex vivo evaluation of its perfusion-thermal functions; (iv) mathematic modeling and computer simulation to confirm the optimal temperature profiles during the thermal ablation process, and; (v) in vivo technical validation using five living rabbits with orthotopic liver tumors. Results: In ex vivo experiments, gross pathology and optical imaging demonstrated the successful spherical distribution/deposition of motexafin gadolinium administered through the new electrode, with a temperature gradient from the electrode core at 80 °C to its periphery at 42 °C. An excellent repeatable correlation of temperature profiles at varying spots, from the center to periphery of the liver tumor, was found between the mathematic simulation and actual animal tumor models (Pearson coefficient ≥0.977). For in vivo validation, indocyanine green (ICG) was directly delivered into the peritumoral zones during simultaneous generation of central tumoral lethal radiofrequency (RF) heat (>60 °C) and peritumoral sublethal RF hyperthermia (<60 °C). Both optical imaging and fluorescent microscopy confirmed successful peritumoral ICG distribution/deposition with increased heat shock protein 70 expression. Conclusion: This new 3D, perfusion-thermal electrode system provided the evidence on the potential to enable simultaneous delivery of therapeutic agents and RF hyperthermia into the difficult-to-treat peritumoral zones, creating a new strategy to address the critical limitation, i.e., the high incidence of residual and recurrent tumor following thermal ablation of unresectable medium-to-large and irregular tumors.

Towards a heuristic understanding of the storage effect.

The storage effect is a general explanation for coexistence in a variable environment. Unfortunately, the storage effect is poorly understood, in part because the generality of the storage effect precludes an interpretation that is simultaneously simple, intuitive and correct. Here, we explicate the storage effect by dividing one of its key conditions-covariance between environment and competition-into two pieces, namely that there must be a strong causal relationship between environment and competition, and that the effects of the environment do not change too quickly. This finer-grained definition can explain a number of previous results, including (1) that the storage effect promotes annual plant coexistence when the germination rate fluctuates, but not when the seed yield fluctuates, (2) that the storage effect is more likely to be induced by resource competition than the apparent competition, and (3) why the storage effect arises readily in models with either stage structure or environmental autocorrelation. Additionally, our expanded definition suggests two novel mechanisms by which the temporal storage effect can arise-transgenerational plasticity and causal chains of environmental variables-thus suggesting that the storage effect is a more common phenomenon than previously thought.

A dedicated breast-PET/CT scanner: Numerical observer study of lesion detection.

BACKGROUND: Dedicated, breast-specific positron emission tomography (BPET)-cone-beam computed tomography (BPET/CT) systems have been developed to improve detection and diagnosis of cancer in women with indeterminate mammograms caused by radiodense breasts. The absorption of X-rays that often vexes mammography in this subset of women does not affect the detection of the high energy annihilation photons used in PET. PET imaging of the breast, however, is subject to limitations caused by their comparatively low spatial resolution (∼2 mm) and often moderate radiotracer uptake in lesions. PURPOSE: The purpose of this investigation is to explore the PET-based lesion detection capabilities of a BPET/CT scanner developed by the Department of Radiology Instrumentation group at West Virginia University. METHODS: The PET component of the system consists of a rotating pair of 96 × 72 arrays of 2 × 2 × 15 mm3 LYSO scintillator elements. The cone-beam-CT component utilized a pulsed X-ray source and flat panel detector operated in portrait orientation. The density maps created by the CT scanner were used to correct the BPET data for photon attenuation and Compton scattering. The nonuniform uptake of 18 F-fluorodeoxyglucose (FDG) in normal breast tissue was emulated in a specially designed phantom consisting of an acrylic cylinder filled with a mixture of acrylic beads and liquid containing FDG. FDG-avid lesions were simulated with agar spheres (3, 4, 6, 8, and 10 mm diameters) containing vary amounts of FDG to produce target-to-background ratios (TBR) of 6:1, 8:1, and 10:1. The spheres also contained X-ray contrast agent to make even the smallest ones readily visible in CT images. Positions of all the lesions were identified in the CT images. These positions were used to extract signal present and signal absent sub-images from the PET images. The sub-images were then input to software that calculated areas-under-the-curve for two numerical model observers (Laguerre-Gauss channelized Hotelling observer and non-prewhitening matched filter). RESULTS: The results showed that the smallest detectable lesion with this system is no smaller than ∼3 mm in diameter with a TBR of 6:1. Simulated lesions with diameters of 4 mm and greater were calculated to have good to excellent likelihood of detection for all TBRs tested. CONCLUSION: The results from this investigation identified the detectability capabilities and limitations for a dedicated breast-PET/CT scanner. Its ability to detect relatively small simulated FDG-avid breast lesions for a range of TBRs indicates its potential for clinical application. Finally, the study used methodologies that could be applied to a detectability assessment of other PET/CT scanners.

Complexities of cooccurrence of catatonia and autoimmune thyroiditis in bipolar disorder: A case series and selective review.

In recent years the neurobiological underpinnings of catatonia have been an emerging area of interest. Catatonia is frequently encountered in mood disorders, neurological disorders and systemic illnesses. Furthermore, the manifestation of catatonia in autoimmune disorders such as NMDA receptor antibody encephalitis and thyroiditis reinforces its neuropsychiatric nature. Irrespective of cause benzodiazepines and electroconvulsive therapy remain the standard treatments for catatonia, although a proportion fail to respond to the same. This report describes three women with pre-existing bipolar disorder presenting in catatonia. Interestingly in all three, while benzodiazepines and electroconvulsive therapy failed, a dramatic resolution of catatonia with corticosteroids was noted following the detection of Hashimoto's thyroiditis. Hashimoto's encephalopathy presenting as catatonia has been reported, but our patients' profile differed in having had an a priory diagnosis of bipolar disorder. Given that both catatonia and thyroid dysfunction are frequently encountered in bipolar disorder, Hashimoto's encephalopathy as a potential cause for this concurrent manifestation in bipolar disorder may be overlooked. Therefore, it is essential to suspect Hashimoto's encephalopathy when catatonia manifests in bipolar disorder. A timely evaluation would be prudent as they may fail to respond to standard treatments for catatonia but respond remarkably to corticosteroids, saving much time and angst. Recent evidence implicates immune system dysfunction, with neuroinflammation and peripheral immune dysregulation contributing to the pathophysiology of bipolar disorder as well as catatonia. Findings from this study reaffirm the role of immune system dysfunction common to the etiopathogenesis of all these disorders, highlighting the complex interplay between catatonia, thyroiditis and bipolar disorder.

Uneven but Conservative Pacing Is Associated With Performance During Uphill and Downhill Running.

PURPOSE: To investigate the relationship between pacing strategy and performance during uphill and downhill running-specifically, what distribution of energy corresponds to faster race finish times between and among participants. METHODS: Eighteen years of race data from a 10.2-mile running race with an uphill first half and a downhill second half were analyzed to identify relationships between pacing and performance. A pacing coefficient (PC), equal to a participant's ascent time divided by finishing time (FT), was used to define each participant's pacing strategy. The American College of Sports Medicine metabolic running equation was used to estimate energy expenditure during the ascent, descent, and total race. Statistical analyses compared participants' PC to their FT and finishing place within their age and gender category. Additionally, FT and finishing place were compared between groups of participants who exhibited similar pacing strategies. RESULTS: PCs were positively associated with faster FTs (r2 = .120, P < .001) and better finishing positions (r2 = .104, P < .001). PCs above .600 were associated with the fastest average FTs and best average finishing position within age and gender categories (all P ≤ .047). CONCLUSIONS: Participants performed the best when energy expenditure increased no more than 10.4% during the uphill portion compared to their overall average. It is not possible to state that overly aggressive uphill efforts resulted in premature fatigue and thus slower decent times and worse race performance. However, participants should still avoid overly aggressive uphill pacing, as performance was associated with larger PCs.