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1.
Am J Physiol Endocrinol Metab ; 327(1): E42-E54, 2024 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-38717363

RESUMEN

Skeletal muscle microvascular blood flow (MBF) plays an important role in glucose disposal in muscle. Impairments in muscle MBF contribute to insulin resistance and prediabetes. Animal studies show that short-term (3 day) high-fat feeding blunts skeletal muscle MBF before impairing insulin-stimulated glucose disposal. It is not known whether this occurs in humans. We investigated the temporal impact of a 7-day high-calorie high-fat (HCHF) diet intervention (+52% kJ; 41% fat) on fasting and postprandial cardiometabolic outcomes in 14 healthy adults (18-37 yr). Metabolic health and vascular responses to a mixed-meal challenge (MMC) were measured at pre (day 0)-, mid (day 4)- and post (day 8)-intervention. There were no significant differences in body weight, body fat %, fasting blood glucose, and fasting plasma insulin concentrations at pre-, mid- and postintervention. Compared with preintervention there was a significant increase in insulin (but not glucose) total area under the curve in response to the MMC at midintervention (P = 0.041) and at postintervention (P = 0.028). Unlike at pre- and midintervention, at postintervention muscle MBF decreased at 60 min (P = 0.024) and 120 min (P = 0.023) after the MMC. However, macrovascular blood flow was significantly increased from 0 to 60 min (P < 0.001) and 120 min (P < 0.001) after the MMC at pre-, mid- and postintervention. Therefore, short-term HCHF feeding in healthy individuals leads to elevated postprandial insulin but not glucose levels and a blunting of meal-induced skeletal muscle MBF responses but not macrovascular blood flow responses.NEW & NOTEWORTHY This is the first study to investigate skeletal muscle microvascular blood flow (MBF) responses in humans after short-term high-calorie high-fat (HCHF) diet. The main findings were that HCHF diet causes elevated postprandial insulin in healthy individuals within 3 days and blunts meal-induced muscle MBF within 7 days, despite no impairments in postprandial glucose or macrovascular blood flow.


Asunto(s)
Glucemia , Dieta Alta en Grasa , Hiperinsulinismo , Insulina , Músculo Esquelético , Periodo Posprandial , Humanos , Adulto , Masculino , Músculo Esquelético/irrigación sanguínea , Músculo Esquelético/metabolismo , Adulto Joven , Femenino , Adolescente , Periodo Posprandial/fisiología , Insulina/sangre , Glucemia/metabolismo , Flujo Sanguíneo Regional , Microcirculación/fisiología , Resistencia a la Insulina/fisiología , Voluntarios Sanos , Microvasos , Ayuno
2.
Neurosurg Rev ; 47(1): 48, 2024 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-38224410

RESUMEN

Tranexamic acid (TXA) has long been utilized in spine surgery and can be administered through intravenous (IV) and topical routes. Although, topical and IV administration of TXA are both effective in decreasing blood loss during spine surgery, complications like deep vein thrombosis (DVT) and pulmonary embolism have been reported with the use of intravenous TXA (ivTXA). These potential complications may be mitigated through the use of topical TXA (tTXA). To assess optimal dosing protocols and efficacy of topical TXA in spine surgery, Embase, Ovid-MEDLINE, Scopus, Cochrane, and clinicaltrials.gov were queried for original research on the use of tTXA in adult patients undergoing spine surgery. Data parameters analyzed included blood loss, transfusion rate, thromboembolic, and other complications. Data was synthesized and confidence evaluated according to the Grades of Recommendation, Assessment, Development, and Evaluation approach. Nineteen studies were included in the final analysis with 2197 patients. Of the 18 published studies, 9 (50%) displayed high levels of evidence. Topical TXA showed a trend towards a lower risk of transfusion and complications. Protocols that used 1g tTXA showed a significantly reduced risk for transfusion when compared to controls (risk ratio -1.05, 95% CI (-1.62, -0.48); P = 0.94, I2 = 0%). Complications associated with tTXA included DVTs and wound infections. Topical TXA was non-inferior to intravenous TXA with similar efficacy and complication profiles for bleeding control in spine surgery; however, more studies are needed to discern benefits and risks.


Asunto(s)
Embolia Pulmonar , Ácido Tranexámico , Adulto , Humanos , Ácido Tranexámico/uso terapéutico , Oportunidad Relativa
3.
Eur Spine J ; 2024 Mar 24.
Artículo en Inglés | MEDLINE | ID: mdl-38522054

RESUMEN

PURPOSE: Operative treatment of adult spinal deformity (ASD) has been shown to improve patient health-related quality of life (HRQOL). Selection of the uppermost instrumented vertebra (UIV) in either the upper thoracic (UT) or lower thoracic (LT) spine is a pivotal decision with effects on operative and postoperative outcomes. This review overviews the multifaceted decision-making process for UIV selection in ASD correction. METHODS: PubMed was queried for articles using the keywords "uppermost instrumented vertebra", "upper thoracic", "lower thoracic", and "adult spinal deformity". RESULTS: Optimization of UIV selection may lead to superior deformity correction, better patient-reported outcomes, and lower risk of proximal junctional kyphosis (PJK) and failure (PJF). Patient alignment characteristics, including preoperative thoracic kyphosis, coronal deformity, and the magnitude of sagittal correction influence surgical decision-making when selecting a UIV, while comorbidities such as poor body mass index, osteoporosis, and neuromuscular pathology should also be taken in to account. Additionally, surgeon experience and resources available to the hospital may also play a role in this decision. Currently, it is incompletely understood whether postoperative HRQOLs, functional and radiographic outcomes, and complications after surgery differ between selection of the UIV in either the UT or LT spine. CONCLUSION: The correct selection of the UIV in surgical planning is a challenging task, which requires attention to preoperative alignment, patient comorbidities, clinical characteristics, available resources, and surgeon-specific factors such as experience.

4.
J Sports Sci ; 42(1): 85-101, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38393985

RESUMEN

This study examined the influence of resistance training (RT) proximity-to-failure, determined by repetitions-in-reserve (RIR), on quadriceps hypertrophy and neuromuscular fatigue. Resistance-trained males (n = 12) and females (n = 6) completed an 8-week intervention involving two RT sessions per week. Lower limbs were randomised to perform the leg press and leg extension exercises either to i) momentary muscular failure (FAIL), or ii) a perceived 2-RIR and 1-RIR, respectively (RIR). Muscle thickness of the quadriceps [rectus femoris (RF) and vastus lateralis (VL)] and acute neuromuscular fatigue (i.e., repetition and lifting velocity loss) were assessed. Data was analysed with Bayesian linear mixed-effect models. Increases in quadriceps thickness (average of RF and VL) from pre- to post-intervention were similar for FAIL [0.181 cm (HDI: 0.119 to 0.243)] and RIR [0.182 cm (HDI: 0.115 to 0.247)]. Between-protocol differences in RF thickness slightly favoured RIR [-0.036 cm (HDI: -0.113 to 0.047)], but VL thickness slightly favoured FAIL [0.033 cm (HDI: -0.046 to 0.116)]. Mean volume was similar across the RT intervention between FAIL and RIR. Lifting velocity and repetition loss were consistently greater for FAIL versus RIR, with the magnitude of difference influenced by the exercise and the stage of the RT intervention.


Terminating RT sets with a close proximity-to-failure (e.g., 1- to 2-RIR) can be sufficient to promote similar hypertrophy of the quadriceps as reaching momentary muscular failure in resistance-trained individuals over eight weeks, but the overall influence of proximity-to-failure on muscle-specific hypertrophy may also depend on other factors (e.g., exercise selection, order, and subsequent musculature targeted).Due to high repetition loss (from the first to final set) when sets are terminated at momentary muscular failure, performing RT with 1- to 2-RIR allows for similar volume load and repetition volume accumulation as reaching momentary muscular failure across eight weeks, possibly influencing the overall RT stimulus achieved.Performing RT to momentary muscular failure consistently induces higher levels of acute neuromuscular fatigue versus RT performed with 1- to 2-RIR; however, improved fatigue resistance overtime may attenuate acute neuromuscular fatigue and subsequent repetition loss (but may depend on the exercise performed).


Asunto(s)
Entrenamiento de Fuerza , Masculino , Femenino , Humanos , Entrenamiento de Fuerza/métodos , Teorema de Bayes , Fuerza Muscular/fisiología , Adaptación Fisiológica , Músculo Cuádriceps/fisiología , Hipertrofia , Músculo Esquelético/fisiología
5.
J Strength Cond Res ; 38(3): e78-e85, 2024 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-37967832

RESUMEN

ABSTRACT: Refalo, MC, Remmert, JF, Pelland, JC, Robinson, ZP, Zourdos, MC, Hamilton, DL, Fyfe, JJ, and Helms, ER. Accuracy of intraset repetitions-in-reserve predictions during the bench press exercise in resistance-trained male and female subjects. J Strength Cond Res 38(3): e78-e85, 2024-This study assessed the accuracy of intraset repetitions-in-reserve (RIR) predictions to provide evidence for the efficacy of RIR prescription as a set termination method to inform proximity to failure during resistance training (RT). Twenty-four resistance trained male ( n = 12) and female ( n = 12) subjects completed 2 experimental sessions involving 2 sets performed to momentary muscular failure (barbell bench press exercise) with 75% of 1 repetition maximum (1RM), whereby subjects verbally indicated when they perceived to had reached either 1 RIR or 3 RIR. The difference between the predicted RIR and the actual RIR was defined as the "RIR accuracy" and was quantified as both raw (i.e., direction of error) and absolute (i.e., magnitude of error) values. High raw and absolute mean RIR accuracy (-0.17 ± 1.00 and 0.65 ± 0.78 repetitions, respectively) for 1-RIR and 3-RIR predictions were observed (including all sets and sessions completed). We identified statistical equivalence (equivalence range of ±1 repetition, thus no level of statistical significance was set) in raw and absolute RIR accuracy between (a) 1-RIR and 3-RIR predictions, (b) set 1 and set 2, and (c) session 1 and session 2. No evidence of a relationship was found between RIR accuracy and biological sex, years of RT experience, or relative bench press strength. Overall, resistance-trained individuals are capable of high absolute RIR accuracy when predicting 1 and 3 RIR on the barbell bench press exercise, with a minor tendency for underprediction. Thus, RIR prescriptions may be used in research and practice to inform the proximity to failure achieved upon set termination.


Asunto(s)
Músculo Esquelético , Entrenamiento de Fuerza , Humanos , Masculino , Femenino , Levantamiento de Peso , Terapia por Ejercicio , Ejercicio Físico , Entrenamiento de Fuerza/métodos , Fuerza Muscular
6.
J Nucl Cardiol ; 30(1): 193-200, 2023 02.
Artículo en Inglés | MEDLINE | ID: mdl-36417121

RESUMEN

BACKGROUND: Radionuclide ventriculography (RNVG) can be used to quantify mechanical dyssynchrony and may be a valuable adjunct in the assessment of heart failure with reduced ejection fraction (HFrEF). The study aims to investigate the effect of beta-blockers on mechanical dyssynchrony using novel RNVG phase parameters. METHODS: A retrospective study was carried out in a group of 98 patients with HFrEF. LVEF and dyssynchrony were assessed pre and post beta-blockade. Dyssynchrony was assessed using synchrony, entropy, phase standard deviation, approximate entropy, and sample entropy from planar RNVG phase images. Subgroups split by ischemic etiology were also investigated. RESULTS: An improvement in dyssynchrony and LVEF was measured six months post beta-blockade for both ischemic and non-ischemic groups. CONCLUSIONS: A significant improvement in dyssynchrony and LVEF was measured post beta-blockade using novel measures of dyssynchrony.


Asunto(s)
Insuficiencia Cardíaca , Disfunción Ventricular Izquierda , Humanos , Estudios Retrospectivos , Volumen Sistólico , Ventriculografía con Radionúclidos , Imagen de Acumulación Sanguínea de Compuerta
7.
Eur J Appl Physiol ; 123(9): 1911-1928, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-37185932

RESUMEN

PURPOSE: Evolving investigative techniques are providing greater understanding about the early neuromuscular responses to resistance training among novice exercisers. The aim of this study was to investigate the time-course of changes in muscle contractile mechanics, architecture, neuromuscular, and strength adaptation during the first 6-weeks of lower-limb resistance training. METHODS: Forty participants: 22 intervention (10 males/12 females; 173.48 ± 5.20 cm; 74.01 ± 13.13 kg) completed 6-week resistance training, and 18 control (10 males/8 females; 175.52 ± 7.64 cm; 70.92 ± 12.73 kg) performed no resistance training and maintained their habitual activity. Radial muscle displacement (Dm) assessed via tensiomyography, knee extension maximal voluntary contraction (MVC), voluntary activation (VA), corticospinal excitability and inhibition via transcranial magnetic stimulation, motor unit (MU) firing rate, and muscle thickness and pennation angle via ultrasonography were assessed before and after 2, 4, and 6-weeks of dynamic lower-limb resistance training or control. RESULTS: After 2-weeks training, Dm reduced by 19-25% in the intervention group; this was before any changes in neural or morphological measures. After 4-weeks training, MVC increased by 15% along with corticospinal excitability by 16%; however, there was no change in VA, corticospinal inhibition, or MU firing rate. After 6-weeks training there was further MVC increase by 6% along with muscle thickness by 13-16% and pennation angle by 13-14%. CONCLUSION: Enhanced contractile properties and corticospinal excitability occurred before any muscle architecture, neural, and strength adaptation. Later increases in muscular strength can be accounted for by architectural adaptation.


Asunto(s)
Contracción Muscular , Músculo Esquelético , Masculino , Femenino , Humanos , Electromiografía , Músculo Esquelético/fisiología , Contracción Muscular/fisiología , Fuerza Muscular/fisiología , Extremidad Inferior , Estimulación Magnética Transcraneal/métodos , Potenciales Evocados Motores/fisiología
8.
Nurs Educ Perspect ; 2023 Mar 08.
Artículo en Inglés | MEDLINE | ID: mdl-36881514

RESUMEN

ABSTRACT: Postpartum hemorrhage (PPH) is the leading cause of maternal mortality and morbidity. Effective nurse training for PPH management can reduce negative health impacts on childbearing women. This article discusses a framework for the development of an innovative immersive virtual reality simulator for PPH management training. The simulator should consist of: 1) a virtual world, including virtual physical and social environments, and simulated patients, and 2) a smart platform, providing automatic instructions, adaptive scenarios, and intelligent performance debriefing and evaluations. This simulator will provide a realistic virtual environment for nurses to practice PPH management and promote women's health.

9.
Osteoarthritis Cartilage ; 30(1): 61-68, 2022 01.
Artículo en Inglés | MEDLINE | ID: mdl-34534662

RESUMEN

OBJECTIVE: To determine whether good versus poor outcome trajectories and predictors of poor outcome obtained in a derivation study could be replicated in an independent sample of persons undergoing knee arthroplasty (KA). METHODS: We used data from TRIO-POPULAR, a prospective cohort study of 926 participants who underwent KA in the United Kingdom. The participants were assessed preoperatively and 6-weeks, 6- and 12-months postoperatively. The Oxford Knee Score was the primary outcome and a variety of pre-operative predictors of outcome were selected. The outcome measure and the predictors were selected to most closely align with a previously published derivation study of good versus poor outcome. Confirmatory two-piece latent class growth curve analyses were used to model outcome and regression was used to identify predictors of outcome class. RESULTS: Trajectories for the Oxford Knee Scores from TRIO-POPULAR replicated trajectories for WOMAC Pain and Function scores from the previously published derivation study. Multivariable predictors of poor outcome were pain catastrophizing (odds ratio = 1.125, 95% CI = 1.048, .206, p = 0.001) and comorbidity (odds ratio = 1.134, 95%CI = 1.049, 1.227, p = 0.002. Pain catastrophizing also predicted poor outcome in the derivation study. CONCLUSIONS: Good and poor outcome trajectories replicated those found in the previously published derivation study. Our model-based method produces stable outcome trajectories despite using data from different countries and participants with substantively different characteristics. Predictors of poor outcome were somewhat inconsistent between the cross-validation and derivation studies. Pain catastrophizing was the only consistent poor outcome predictor.


Asunto(s)
Artroplastia de Reemplazo de Rodilla , Osteoartritis de la Rodilla/cirugía , Medición de Resultados Informados por el Paciente , Autoinforme , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos
10.
J Nucl Cardiol ; 29(2): 581-589, 2022 04.
Artículo en Inglés | MEDLINE | ID: mdl-32748278

RESUMEN

BACKGROUND: Accurate diagnostic tools to identify patients at risk of cancer therapy-related cardiac dysfunction (CTRCD) are critical. For patients undergoing cardiotoxic cancer therapy, ejection fraction assessment using radionuclide ventriculography (RNVG) is commonly used for serial assessment of left ventricular (LV) function. METHODS: In this retrospective study, approximate entropy (ApEn), synchrony, entropy, and standard deviation from the phase histogram (phase SD) were investigated as potential early markers of LV dysfunction to predict CTRCD. These phase parameters were calculated from the baseline RNVG phase image for 177 breast cancer patients before commencing cardiotoxic therapy. RESULTS: Of the 177 patients, 11 had a decline in left ventricular ejection fraction (LVEF) of over 10% to an LVEF below 50% after treatment had commenced. This patient group had a significantly higher ApEn at baseline to those who maintained a normal LVEF throughout treatment. Of the parameters investigated, ApEn was superior for predicting the risk of CTRCD. Combining ApEn with the baseline LVEF further improved the discrimination between the groups. CONCLUSIONS: The results suggest that RNVG phase analysis using approximate entropy may aid in the detection of sub-clinical LV contraction abnormalities, not detectable by baseline LVEF measurement, predicting a subsequent decline in LVEF.


Asunto(s)
Neoplasias de la Mama , Cardiopatías , Disfunción Ventricular Izquierda , Neoplasias de la Mama/diagnóstico por imagen , Neoplasias de la Mama/tratamiento farmacológico , Cardiotoxicidad , Femenino , Humanos , Ventriculografía con Radionúclidos , Estudios Retrospectivos , Medición de Riesgo , Volumen Sistólico , Disfunción Ventricular Izquierda/inducido químicamente , Disfunción Ventricular Izquierda/diagnóstico por imagen , Función Ventricular Izquierda
11.
Geophys Res Lett ; 49(13): e2022GL098016, 2022 Jul 16.
Artículo en Inglés | MEDLINE | ID: mdl-36245954

RESUMEN

Distinctively-light isotopic signatures associated with Fe released from anthropogenic activity have been used to trace basin-scale impacts. However, this approach is complicated by the way Fe cycle processes modulate oceanic dissolved Fe (dFe) signatures (δ56Fediss) post deposition. Here we include dust, wildfire, and anthropogenic aerosol Fe deposition in a global ocean biogeochemical model with active Fe isotope cycling, to quantify how anthropogenic Fe impacts surface ocean dFe and δ56Fediss. Using the North Pacific as a natural laboratory, the response of dFe, δ56Fediss, and primary productivity are spatially and seasonally variable and do not simply follow the footprint of atmospheric deposition. Instead, the effect of anthropogenic Fe is regulated by the biogeochemical regime, specifically the degree of Fe limitation and rates of primary production. Overall, we find that while δ56Fediss does trace anthropogenic input, the response is muted by fractionation during phytoplankton uptake, but amplified by other isotopically-light Fe sources.

12.
Nature ; 540(7631): 94-96, 2016 12 01.
Artículo en Inglés | MEDLINE | ID: mdl-27851735

RESUMEN

The deep nitrogen-covered basin on Pluto, informally named Sputnik Planitia, is located very close to the longitude of Pluto's tidal axis and may be an impact feature, by analogy with other large basins in the Solar System. Reorientation of Sputnik Planitia arising from tidal and rotational torques can explain the basin's present-day location, but requires the feature to be a positive gravity anomaly, despite its negative topography. Here we argue that if Sputnik Planitia did indeed form as a result of an impact and if Pluto possesses a subsurface ocean, the required positive gravity anomaly would naturally result because of shell thinning and ocean uplift, followed by later modest nitrogen deposition. Without a subsurface ocean, a positive gravity anomaly requires an implausibly thick nitrogen layer (exceeding 40 kilometres). To prolong the lifetime of such a subsurface ocean to the present day and to maintain ocean uplift, a rigid, conductive water-ice shell is required. Because nitrogen deposition is latitude-dependent, nitrogen loading and reorientation may have exhibited complex feedbacks.

13.
J Sports Sci ; 40(12): 1369-1391, 2022 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-35658845

RESUMEN

While proximity-to-failure is considered an important resistance training (RT) prescription variable, its influence on physiological adaptations and short-term responses to RT is uncertain. Given the ambiguity in the literature, a scoping review was undertaken to summarise evidence for the influence of proximity-to-failure on muscle hypertrophy, neuromuscular fatigue, muscle damage and perceived discomfort. Literature searching was performed according to PRISMA-ScR guidelines and identified three themes of studies comparing either: i) RT performed to momentary muscular failure versus non-failure, ii) RT performed to set failure (defined as anything other than momentary muscular failure) versus non-failure, and iii) RT performed to different velocity loss thresholds. The findings highlight that no consensus definition for "failure" exists in the literature, and the proximity-to-failure achieved in "non-failure" conditions is often ambiguous and variable across studies. This poses challenges when deriving practical recommendations for manipulating proximity-to-failure in RT to achieve desired outcomes. Based on the limited available evidence, RT to set failure is likely not superior to non-failure RT for inducing muscle hypertrophy, but may exacerbate neuromuscular fatigue, muscle damage, and post-set perceived discomfort versus non-failure RT. Together, these factors may impair post-exercise recovery and subsequent performance, and may also negatively influence long-term adherence to RT.KEY POINTS This scoping review identified three broad themes of studies investigating proximity-to-failure in RT, based on the specific definition of set failure used (and therefore the research question being examined), to improve the validity of study comparisons and interpretations.There is no consensus definition for set failure in RT, and the proximity-to-failure achieved during non-failure RT is often unclear and varies both within and between studies, which together poses challenges when interpreting study findings and deriving practical recommendations regarding the influence of RT proximity-to-failure on muscle hypertrophy and other short-term responses.Based on the limited available evidence, performing RT to set failure is likely not superior to non-failure RT to maximise muscle hypertrophy, but the optimal proximity to failure in RT for muscle hypertrophy is unclear and may be moderated by other RT variables (e.g., load, volume-load). Also, RT performed to set failure likely induces greater neuromuscular fatigue, muscle damage, and perceived discomfort than non-failure RT, which may negatively influence RT performance, post-RT recovery, and long-term adherence.


Asunto(s)
Entrenamiento de Fuerza , Adaptación Fisiológica/fisiología , Humanos , Hipertrofia , Fatiga Muscular , Fuerza Muscular/fisiología , Músculo Esquelético/fisiología , Entrenamiento de Fuerza/efectos adversos
14.
J Sports Sci ; 40(15): 1700-1711, 2022 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-35852164

RESUMEN

Training interventions often have small effects and are tested in small samples. We used a Bayesian approach to examine the change in jump distance after different resistance training programmes. Thirty-three 18- to 45-year-old males completed one of three lower limb resistance training programmes: deadlift (DL), hip thrust (HT) or back squat (BS). Horizontal and vertical jump performance was assessed over the training intervention. Examination of Bayesian posterior distributions for jump distance estimated that the probability of a change above a horizontal jump smallest worthwhile change (SWC) of 4.7 cm for the DL group was ~12%. For the HT and BS groups, the probability of a change above the SWC was ~87%. The probability of a change above a vertical jump SWC of 1.3 cm for the DL group was ~31%. For the HT and BS groups, the probability of a change above the vertical jump SWC was ~62% and ~67%, respectively. Our study illustrates that a Bayesian approach provides a rich inferential interpretation for small sample training studies with small effects. The extra information from such a Bayesian approach is useful to practitioners in Sport and Exercise Science where small effects are expected and sample size is often constrained.


Asunto(s)
Rendimiento Atlético , Entrenamiento de Fuerza , Adolescente , Adulto , Teorema de Bayes , Prueba de Esfuerzo , Humanos , Masculino , Persona de Mediana Edad , Fuerza Muscular , Posición de Pie , Adulto Joven
15.
Nature ; 522(7554): 45-9, 2015 Jun 04.
Artículo en Inglés | MEDLINE | ID: mdl-26040889

RESUMEN

Four small moons--Styx, Nix, Kerberos and Hydra--follow near-circular, near-equatorial orbits around the central 'binary planet' comprising Pluto and its large moon, Charon. New observational details of the system have emerged following the discoveries of Kerberos and Styx. Here we report that Styx, Nix and Hydra are tied together by a three-body resonance, which is reminiscent of the Laplace resonance linking Jupiter's moons Io, Europa and Ganymede. Perturbations by the other bodies, however, inject chaos into this otherwise stable configuration. Nix and Hydra have bright surfaces similar to that of Charon. Kerberos may be much darker, raising questions about how a heterogeneous satellite system might have formed. Nix and Hydra rotate chaotically, driven by the large torques of the Pluto-Charon binary.

16.
Eur Spine J ; 30(8): 2157-2166, 2021 08.
Artículo en Inglés | MEDLINE | ID: mdl-33856551

RESUMEN

PURPOSE: AI algorithms have shown promise in medical image analysis. Previous studies of ASD clusters have analyzed alignment metrics-this study sought to complement these efforts by analyzing images of sagittal anatomical spinopelvic landmarks. We hypothesized that an AI algorithm would cluster preoperative lateral radiographs into groups with distinct morphology. METHODS: This was a retrospective review of a multicenter, prospectively collected database of adult spinal deformity. A total of 915 patients with adult spinal deformity and preoperative lateral radiographs were included. A 2 × 3, self-organizing map-a form of artificial neural network frequently employed in unsupervised classification tasks-was developed. The mean spine shape was plotted for each of the six clusters. Alignment, surgical characteristics, and outcomes were compared. RESULTS: Qualitatively, clusters C and D exhibited only mild sagittal plane deformity. Clusters B, E, and F, however, exhibited marked positive sagittal balance and loss of lumbar lordosis. Cluster A had mixed characteristics, likely representing compensated deformity. Patients in clusters B, E, and F disproportionately underwent 3-CO. PJK and PJF were particularly prevalent among clusters A and E. Among clusters B and F, patients who experienced PJK had significantly greater positive sagittal balance than those who did not. CONCLUSIONS: This study clustered preoperative lateral radiographs of ASD patients into groups with highly distinct overall spinal morphology and association with sagittal alignment parameters, baseline HRQOL, and surgical characteristics. The relationship between SVA and PJK differed by cluster. This study represents significant progress toward incorporation of computer vision into clinically relevant classification systems in adult spinal deformity. LEVEL OF EVIDENCE IV: Diagnostic: individual cross-sectional studies with the consistently applied reference standard and blinding.


Asunto(s)
Inteligencia Artificial , Lordosis , Adulto , Análisis por Conglomerados , Estudios Transversales , Humanos , Lordosis/diagnóstico por imagen , Lordosis/cirugía , Estudios Retrospectivos
17.
BMC Musculoskelet Disord ; 22(1): 635, 2021 Jul 24.
Artículo en Inglés | MEDLINE | ID: mdl-34303341

RESUMEN

BACKGROUND: Total knee arthroplasty is known to successfully alleviate pain and improve function in endstage knee osteoarthritis. However, there is some controversy with regard to the influence of obesity on clinical benefits after TKA. The aim of this study was to investigate the impact of body mass index (BMI) on improvement in pain, function and general health status following total knee arthroplasty (TKA). METHODS: A single-centre retrospective analysis of primary TKAs performed between 2006 and 2016 was performed. Data were collected preoperatively and 12-month postoperatively using WOMAC score and EQ-5D. Longitudinal score change was compared across the BMI categories identified by the World Health Organization. RESULTS: Data from 1565 patients [mean age 69.1, 62.2% women] were accessed. Weight distribution was: 21.2% BMI < 25.0 kg/m2, 36.9% BMI 25.0-29.9 kg/m2, 27.0% BMI 30.0-34.9 kg/m2, 10.2% BMI 35.0-39.9 kg/m2, and 4.6% BMI ≥ 40.0 kg/m2. All outcome measures improved between preoperative and 12-month follow-up (p < 0.001). In pairwise comparisons against normal weight patients, patients with class I-II obesity showed larger improvement on the WOMAC function and total score. For WOMAC pain improvements were larger for all three obesity classes. CONCLUSIONS: Post-operative improvement in joint-specific outcomes was larger in obese patients compared to normal weight patients. These findings suggest that obese patients may have the greatest benefits from TKA with regard to function and pain relief one year post-op. Well balanced treatment decisions should fully account for both: Higher benefits in terms of pain relief and function as well as increased potential risks and complications. Trial registration This trial has been registered with the ethics committee of Eastern Switzerland (EKOS; Project-ID: EKOS 2020-00,879).


Asunto(s)
Artroplastia de Reemplazo de Rodilla , Osteoartritis de la Rodilla , Anciano , Índice de Masa Corporal , Femenino , Humanos , Articulación de la Rodilla/cirugía , Masculino , Osteoartritis de la Rodilla/cirugía , Medición de Resultados Informados por el Paciente , Estudios Retrospectivos , Suiza , Resultado del Tratamiento
18.
J Sports Sci ; 39(15): 1723-1745, 2021 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-33874848

RESUMEN

This systematic review and meta-analysis determined resistance training (RT) load effects on various muscle hypertrophy, strength, and neuromuscular performance task [e.g., countermovement jump (CMJ)] outcomes. Relevent studies comparing higher-load [>60% 1-repetition maximum (RM) or <15-RM] and lower-load (≤60% 1-RM or ≥ 15-RM) RT were identified, with 45 studies (from 4713 total) included in the meta-analysis. Higher- and lower-load RT induced similar muscle hypertrophy at the whole-body (lean/fat-free mass; [ES (95% CI) = 0.05 (-0.20 to 0.29), P = 0.70]), whole-muscle [ES = 0.06 (-0.11 to 0.24), P = 0.47], and muscle fibre [ES = 0.29 (-0.09 to 0.66), P = 0.13] levels. Higher-load RT further improved 1-RM [ES = 0.34 (0.15 to 0.52), P = 0.0003] and isometric [ES = 0.41 (0.07 to 0.76), P = 0.02] strength. The superiority of higher-load RT on 1-RM strength was greater in younger [ES = 0.34 (0.12 to 0.55), P = 0.002] versus older [ES = 0.20 (-0.00 to 0.41), P = 0.05] participants. Higher- and lower-load RT therefore induce similar muscle hypertrophy (at multiple physiological levels), while higher-load RT elicits superior 1-RM and isometric strength. The influence of RT loads on neuromuscular task performance is however unclear.


Asunto(s)
Fuerza Muscular/fisiología , Músculo Esquelético/anatomía & histología , Músculo Esquelético/fisiología , Entrenamiento de Fuerza/métodos , Crecimiento del Músculo Esquelético/fisiología , Factores de Edad , Índice de Masa Corporal , Humanos , Contracción Isométrica , Fibras Musculares Esqueléticas/fisiología , Percepción/fisiología , Esfuerzo Físico/fisiología , Análisis y Desempeño de Tareas
19.
Knee Surg Sports Traumatol Arthrosc ; 29(5): 1378-1384, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-32691092

RESUMEN

PURPOSE: The forgotten joint score-12 (FJS-12) is an outcome questionnaire designed to evaluate joint awareness. The responsiveness and validity of the English language version of the FJS-12 in patients undergoing hip arthroscopy for femoroacetabular impingement (FAI) is not known. METHODS: Consecutive patients undergoing hip arthroscopy for a diagnosis of FAI were prospectively followed up over a 1 year period. Patients completed preoperative and postoperative FJS-12, EuroQol 5 Dimension (EQ-5D-5L), and the 12-item international hip outcome tool (iHOT-12). We evaluated construct validity with Spearman correlation coefficients for the FJS-12, and responsiveness by way of effect size and ceiling effects. RESULTS: Forty-six patients underwent hip arthroscopy, of which 42 (91%) completed post-operative PROMs at 1 year follow-up. Construct validity was strong with the iHOT-12 (r = 0.87) and also the EQ-5D-5L (r = 0.83). The median postoperative FJS score was 50.2 (IQR 64). The mean change in score for the FJS-12 was 31 points (SD 31) (p < 0.001), with an effect size (Cohen's d) of 1.16. Preoperatively, three patients scored the lowest possible value resulting in a floor effect of 7.1%. Similarly, only three patients (7.1%) scored the best possible score post-operatively. CONCLUSION: This is the first evaluation of the joint awareness concept in the English language version of the FJS-12 following hip arthroscopy for FAI. The FJS-12 is a valid and responsive tool for the assessment of this cohort of patients. LEVEL OF EVIDENCE: II.


Asunto(s)
Artroscopía/métodos , Pinzamiento Femoroacetabular/cirugía , Articulación de la Cadera/cirugía , Medición de Resultados Informados por el Paciente , Adolescente , Adulto , Estudios de Cohortes , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Periodo Posoperatorio , Estudios Prospectivos , Psicometría , Rango del Movimiento Articular , Reproducibilidad de los Resultados , Estadísticas no Paramétricas , Encuestas y Cuestionarios , Resultado del Tratamiento , Adulto Joven
20.
Int Orthop ; 45(10): 2735-2740, 2021 10.
Artículo en Inglés | MEDLINE | ID: mdl-34401932

RESUMEN

INTRODUCTION: Histologic diagnosis of the lesion is important while intramedullary nailing of a pathologic or impending fracture of a long bone. A biopsy can be performed extramedullary using a targeted sampling device such as a pituitary rongeur or intramedullary from the bone removed from the reamer during preparation of the intramedullary canal. The purpose of this study is to compare a cup pituitary rongeur vs. a reaming biopsy from the intramedullary canal during the treatment of pathologic bone lesions with an intramedullary nail. METHODS: An IRB approved retrospective case control study was performed on 46 consecutive patients who underwent an IMN for pathologic fracture or impending pathologic fracture with an obvious lytic lesion with a known metastatic primary. A laryngeal cup pituitary forceps' rongeur was used in 25 patients and the intramedullary reamer as it passed the lesion was used in 21 patients. Histopathology reports were assessed for (1) adequacy of bone sample (defined as containing sufficient bone and marrow-derived tissue to allow complete histological analysis) and (2) tumor tissue diagnosis. A standard approach for IMN was used. RESULTS: Twenty-three of 25 cup biopsy cases (92%) had positive pathology that corresponded to the primary cancer. Eleven of 21 reaming cases (52.4%) had positive pathology that corresponded to the primary cancer (p = 0.0117). CONCLUSION: The use of an intramedullary cup biopsy forceps is better than reamings to diagnose pathological lesions of impending and pathological fractures in long bones caused by metastatic lesions.


Asunto(s)
Biopsia , Fracturas del Fémur , Fijación Intramedular de Fracturas , Fracturas Espontáneas , Neoplasias Óseas/secundario , Estudios de Casos y Controles , Fracturas Espontáneas/diagnóstico , Fracturas Espontáneas/cirugía , Humanos , Estudios Retrospectivos
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