Hip abductor moment arm - a mathematical analysis for proximal femoral replacement

<p>Abstract</p> <p>Background</p> <p>Patients undergoing proximal femoral replacement for tumor resection often have compromised hip abductor muscles resulting in a Trendelenberg limp and hip instability. Commercially available proximal femoral prostheses offer several designs with varying sites of attachment for the abductor muscles, however, no analyses of these configurations have been performed to determine which design provides the longest moment arm for the hip abductor muscles during normal function.</p> <p>Methods</p> <p>This study analyzed hip abductor moment arm through hip adduction and abduction with a trigonometric mathematical model to evaluate the effects of alterations in anatomy and proximal femoral prosthesis design. Prosthesis dimensions were taken from technical schematics that were obtained from the prosthesis manufacturers. Manufacturers who contributed schematics for this investigation were Stryker Orthopaedics and Biomet.</p> <p>Results</p> <p>Superior and lateral displacement of the greater trochanter increased the hip abductor mechanical advantage for single-leg stance and adduction and preserved moment arm in the setting of Trendelenberg gait. Hip joint medialization resulted in less variance of the abductor moment arm through coronal motion. The Stryker GMRS endoprosthesis provided the longest moment arm in single-leg stance.</p> <p>Conclusions</p> <p>Hip abductor moment arm varies substantially throughout the hip's range of motion in the coronal plane. Selection of a proximal femur endoprosthesis with an abductor muscle insertion that is located superiorly and laterally will optimize hip abductor moment arm in single-leg stance compared to one located inferiorly or medially.</p

The Effects of a Pre-Workout Energy Drink on Measures of Physical Performance

The purpose of this study was to investigate the effects of a pre-workout commercial energy drink on parameters of exercise performance, including anaerobic power, muscular endurance, speed, and reaction time. This study used a randomized, double blind, placebo controlled, parallel design. Participants visited the laboratory on two different occasions. On the first visit, participants were assessed for anaerobic power (via a vertical jump test), muscular endurance, reaction time, reactive sprint test, and aerobic power (via a 1.5 mile run). On the second visit, participants were randomly assigned to ingest four ounces of the energy drink beverage or a similar-tasting placebo beverage 30-minutes prior to engaging in these same physical performance tests. The energy drink treatment had no effect on anaerobic power (vertical jump), reaction time, reactive sprint test, or aerobic power. For the push-up to fatigue test, a significant difference (p = 0.014) was observed with the energy drink treatment enhancing performance by 12% as compared to the placebo treatment (improvement of ~ 4%). For the sit-up to fatigue test, a non-significant difference (p = 0.075) was observed with the energy drink treatment resulting in an enhancement of performance by ~13% as compared to no improvement for the placebo treatment. In light of these findings, individuals whose upper-body muscular endurance performance is part of their physical fitness assessment program may benefit from pre-workout energy drink consumption. In contrast, individuals needing to demonstrate anaerobic/aerobic power, or reactive abilities should not expect an improvement in performance from pre-workout energy drink consumption

Polarisation vision: overcoming challenges of working with a property of light we barely see.

In recent years, the study of polarisation vision in animals has seen numerous breakthroughs, not just in terms of what is known about the function of this sensory ability, but also in the experimental methods by which polarisation can be controlled, presented and measured. Once thought to be limited to only a few animal species, polarisation sensitivity is now known to be widespread across many taxonomic groups, and advances in experimental techniques are, in part, responsible for these discoveries. Nevertheless, its study remains challenging, perhaps because of our own poor sensitivity to the polarisation of light, but equally as a result of the slow spread of new practices and methodological innovations within the field. In this review, we introduce the most important steps in designing and calibrating polarised stimuli, within the broader context of areas of current research and the applications of new techniques to key questions. Our aim is to provide a constructive guide to help researchers, particularly those with no background in the physics of polarisation, to design robust experiments that are free from confounding factors

Congenital imprinting disorders: EUCID.net - a network to decipher their aetiology and to improve the diagnostic and clinical care.

Imprinting disorders (IDs) are a group of eight rare but probably underdiagnosed congenital diseases affecting growth, development and metabolism. They are caused by similar molecular changes affecting regulation, dosage or the genomic sequence of imprinted genes. Each ID is characterised by specific clinical features, and, as each appeared to be associated with specific imprinting defects, they have been widely regarded as separate entities. However, they share clinical characteristics and can show overlapping molecular alterations. Nevertheless, IDs are usually studied separately despite their common underlying (epi)genetic aetiologies, and their basic pathogenesis and long-term clinical consequences remain largely unknown. Efforts to elucidate the aetiology of IDs are currently fragmented across Europe, and standardisation of diagnostic and clinical management is lacking. The new consortium EUCID.net (European network of congenital imprinting disorders) now aims to promote better clinical care and scientific investigation of imprinting disorders by establishing a concerted multidisciplinary alliance of clinicians, researchers, patients and families. By encompassing all IDs and establishing a wide ranging and collaborative network, EUCID.net brings together a wide variety of expertise and interests to engender new collaborations and initiatives

Closed-loop insulin delivery during pregnancy complicated by type 1 diabetes.

OBJECTIVE: This study evaluated closed-loop insulin delivery with a model predictive control (MPC) algorithm during early (12-16 weeks) and late gestation (28-32 weeks) in pregnant women with type 1 diabetes. RESEARCH DESIGN AND METHODS: Ten women with type 1 diabetes (age 31 years, diabetes duration 19 years, BMI 24.1 kg/m(2), booking A1C 6.9%) were studied over 24 h during early (14.8 weeks) and late pregnancy (28.0 weeks). A nurse adjusted the basal insulin infusion rate from continuous glucose measurements (CGM), fed into the MPC algorithm every 15 min. Mean glucose and time spent in target (63-140 mg/dL), hyperglycemic (>140 to ≥ 180 mg/dL), and hypoglycemic (140 mg/dL) was 7% (0-40%) in early and 0% (0-6%) in late pregnancy (P = 0.25) and hypoglycemic (<63 mg/dL) was 0% (0-3%) and 0% (0-0%), respectively (P = 0.18). Postprandial glucose control, glucose variability, insulin infusion rates, and CGM sensor accuracy were no different in early or late pregnancy. CONCLUSIONS: MPC algorithm performance was maintained throughout pregnancy, suggesting that overnight closed-loop insulin delivery could be used safely during pregnancy. More work is needed to achieve optimal postprandial glucose control.Diabetes UK (07/0003551), TCC (PDF/01/036), MRC (G0600717

Heterotrimeric G-protein Signaling Is Critical to Pathogenic Processes in Entamoeba histolytica

Heterotrimeric G-protein signaling pathways are vital components of physiology, and many are amenable to pharmacologic manipulation. Here, we identify functional heterotrimeric G-protein subunits in Entamoeba histolytica, the causative agent of amoebic colitis. The E. histolytica Gα subunit EhGα1 exhibits conventional nucleotide cycling properties and is seen to interact with EhGβγ dimers and a candidate effector, EhRGS-RhoGEF, in typical, nucleotide-state-selective fashions. In contrast, a crystal structure of EhGα1 highlights unique features and classification outside of conventional mammalian Gα subfamilies. E. histolytica trophozoites overexpressing wildtype EhGα1 in an inducible manner exhibit an enhanced ability to kill host cells that may be wholly or partially due to enhanced host cell attachment. EhGα1-overexpressing trophozoites also display enhanced transmigration across a Matrigel barrier, an effect that may result from altered baseline migration. Inducible expression of a dominant negative EhGα1 variant engenders the converse phenotypes. Transcriptomic studies reveal that modulation of pathogenesis-related trophozoite behaviors by perturbed heterotrimeric G-protein expression includes transcriptional regulation of virulence factors and altered trafficking of cysteine proteases. Collectively, our studies suggest that E. histolytica possesses a divergent heterotrimeric G-protein signaling axis that modulates key aspects of cellular processes related to the pathogenesis of this infectious organism

Leukotriene antagonists as first-line or add-on asthma controller therapy

Most randomized trials of treatment for asthma study highly selected patients under idealized conditions. METHODS: We conducted two parallel, multicenter, pragmatic trials to evaluate the real-world effectiveness of a leukotriene-receptor antagonist (LTRA) as compared with either an inhaled glucocorticoid for first-line asthma-controller therapy or a long-acting beta(2)-agonist (LABA) as add-on therapy in patients already receiving inhaled glucocorticoid therapy. Eligible primary care patients 12 to 80 years of age had impaired asthma-related quality of life (Mini Asthma Quality of Life Questionnaire [MiniAQLQ] score =6) or inadequate asthma control (Asthma Control Questionnaire [ACQ] score =1). We randomly assigned patients to 2 years of open-label therapy, under the care of their usual physician, with LTRA (148 patients) or an inhaled glucocorticoid (158 patients) in the first-line controller therapy trial and LTRA (170 patients) or LABA (182 patients) added to an inhaled glucocorticoid in the add-on therapy trial. RESULTS: Mean MiniAQLQ scores increased by 0.8 to 1.0 point over a period of 2 years in both trials. At 2 months, differences in the MiniAQLQ scores between the two treatment groups met our definition of equivalence (95% confidence interval [CI] for an adjusted mean difference, -0.3 to 0.3). At 2 years, mean MiniAQLQ scores approached equivalence, with an adjusted mean difference between treatment groups of -0.11 (95% CI, -0.35 to 0.13) in the first-line controller therapy trial and of -0.11 (95% CI, -0.32 to 0.11) in the add-on therapy trial. Exacerbation rates and ACQ scores did not differ significantly between the two groups. CONCLUSIONS: Study results at 2 months suggest that LTRA was equivalent to an inhaled glucocorticoid as first-line controller therapy and to LABA as add-on therapy for diverse primary care patients. Equivalence was not proved at 2 years. The interpretation of results of pragmatic research may be limited by the crossover between treatment groups and lack of a placebo group

A Science-Based Policy for Managing Free-Roaming Cats

Free-roaming domestic cats (i.e., cats that are owned or unowned and are considered ‘at large’) are globally distributed non-native species that have marked impacts on biodiversity and human health. Despite clear scientific evidence of these impacts, free-roaming cats are either unmanaged or managed using scientifically unsupported and ineffective approaches (e.g., trap-neuter-release [TNR]) in many jurisdictions around the world. A critical first initiative for effective, science-driven management of cats must be broader political and legislative recognition of free-roaming cats as a non-native, invasive species. Designating cats as invasive is important for developing and implementing science-based management plans, which should include efforts to prevent cats from becoming free-roaming, policies focused on responsible pet ownership and banning outdoor cat feeding, and better enforcement of existing laws. Using a science-based approach is necessary for responding effectively to the politically charged and increasingly urgent issue of managing free-roaming cat populations

The economic impact of Los Alamos National Laboratory on north-central New Mexico and the state of New Mexico fiscal year 1998

Los Alamos National Laboratory (LANL) is a multidisciplinary, multiprogram laboratory with a mission to enhance national military and economic security through science and technology. Its mission is to reduce the nuclear danger through stewardship of the nation`s nuclear stockpile and through its nonproliferation and verification activities. An important secondary mission is to promote US industrial competitiveness by working with US companies in technology transfer and technology development partnerships. Los Alamos is involved in partnerships and collaborations with other federal agencies, with industry (including New Mexico businesses), and with universities worldwide. For this report, the reference period is FY 1998 (October 1, 1997, through September 30, 1998). It includes two major impact analysis: the impact of LANL activities on north-central New Mexico and the economic impacts of LANL on the state of New Mexico. Total impact represents both direct and indirect responding by business, including induced effects (responding by households). The standard multipliers used in determining impacts result from the inter-industry, input-output models developed for the three-county region and the state of New Mexico