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1.
Annu Rev Biophys ; 2021 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-33710908

RESUMO

The ability of cells to generate mechanical forces, but also to sense, adapt to, and respond to mechanical signals, is crucial for many developmental, postnatal homeostatic, and pathophysiological processes. However, the molecular mechanisms underlying cellular mechanotransduction have remained elusive for many decades, as techniques to visualize and quantify molecular forces across individual proteins in cells were missing. The development of genetically encoded molecular tension sensors now allows the quantification of piconewton-scale forces that act upon distinct molecules in living cells and even whole organisms. In this review, we discuss the physical principles, advantages, and limitations of this increasingly popular method. By highlighting current examples from the literature, we demonstrate how molecular tension sensors can be utilized to obtain access to previously unappreciated biophysical parameters that define the propagation of mechanical forces on molecular scales. We discuss how the methodology can be further developed and provide a perspective on how the technique could be applied to uncover entirely novel aspects of mechanobiology in the future. Expected final online publication date for the Annual Review of Biophysics, Volume 50 is May 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

2.
Nat Commun ; 12(1): 919, 2021 02 10.
Artigo em Inglês | MEDLINE | ID: mdl-33568673

RESUMO

Single-molecule localization microscopy (SMLM) enabling the investigation of individual proteins on molecular scales has revolutionized how biological processes are analysed in cells. However, a major limitation of imaging techniques reaching single-protein resolution is the incomplete and often unknown labeling and detection efficiency of the utilized molecular probes. As a result, fundamental processes such as complex formation of distinct molecular species cannot be reliably quantified. Here, we establish a super-resolution microscopy framework, called quantitative single-molecule colocalization analysis (qSMCL), which permits the identification of absolute molecular quantities and thus the investigation of molecular-scale processes inside cells. The method combines multiplexed single-protein resolution imaging, automated cluster detection, in silico data simulation procedures, and widely applicable experimental controls to determine absolute fractions and spatial coordinates of interacting species on a true molecular level, even in highly crowded subcellular structures. The first application of this framework allowed the identification of a long-sought ternary adhesion complex-consisting of talin, kindlin and active ß1-integrin-that specifically forms in cell-matrix adhesion sites. Together, the experiments demonstrate that qSMCL allows an absolute quantification of multiplexed SMLM data and thus should be useful for investigating molecular mechanisms underlying numerous processes in cells.


Assuntos
Proteínas do Citoesqueleto/química , Integrina beta1/química , Proteínas Musculares/química , Imagem Individual de Molécula/métodos , Talina/química , Animais , Adesão Celular , Linhagem Celular , Humanos , Camundongos , Imagem Individual de Molécula/instrumentação
3.
J Neurotrauma ; 2020 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-33176582

RESUMO

Concussions are frequent in sports and can contribute to significant and long-lasting neurological disability. Adolescents are particularly susceptible to concussions, with accurate determination of the injury challenging. Our previous study demonstrated that concussion diagnoses could be aided by metabolomics profiling and machine learning, with particular weighting on changes in plasma glycerophospholipids (PCs). Here, our aim was to report directional change of PCs after concussion and to develop a diagnostic concussion panel utilizing a minimum number of plasma PCs. To this end, we enrolled 12 concussed male athletes at our academic Sport Medicine Concussion Clinic, as well as 17 sex-, age- and activity-matched healthy controls. Blood was drawn and 71 plasma PCs were measured for statistically significant changes within 72 hours of injury, and individual PCs were further analyzed with receiver operating characteristic (ROC) curves. Our data demonstrate that 26 of 71 PCs measured were significantly decreased after sports related concussion (P<0.01). None of the PCs increased in plasma after concussion. ROC curve analyses identified the top 4 PCs with areas-under-the curves (AUCs) ≥ 0.86 for concussion diagnosis; PCaeC36:0 (0.92, P<0.001); PCaaC42:6 (0.90, P<0.001); PCaeC36:2 (0.86, P=0.001) and PCaaC32:0 (0.86, P=0.001). Cut off values in M were ≤ to 0.31, 0.22, 5.07 and 4.63, respectively. Importantly, combining these 4 PCs produced an AUC of 0.96 for concussion diagnoses (P<0.001; 95% CI 0.89, 1.00). Our data suggest that as few as 4 circulating PCs may provide excellent diagnostic potential for adolescent concussion. External validation is required in larger cohorts.

4.
CJEM ; 22(5): 603-607, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32576321

RESUMO

INTRODUCTION: Emergency medicine (EM) is a high-risk specialty for burnout. COVID-19 has had and will continue to have important consequences on wellness and burnout for EM physicians in Canada. Baseline data are crucial to monitor the health of EM physicians in Canada, and evaluate any interventions designed to help during and after COVID-19. OBJECTIVES: To describe the rates of burnout, depression, and suicidality in practicing EM physicians in Canada, just before the COVID-19 pandemic. METHODS: A modified snowball method was used for survey distribution. Participants completed the Maslach Burnout Inventory - Health Services Tool (MBI-HSS), a screening measure for depression (PHQ-9), and a question regarding if the physician had ever or in the past 12 months contemplated suicide. RESULTS: A total of 384 respondent surveys were included in the final analysis: 86.1% (329/382) met at least one of the criteria for burnout, 58% (217/374) scored minimal to none on the PHQ-9 screening tool for depression, 14.3% (53/371) had contemplated suicide during their staff career in EM, and of those, 5.9% (22/371) had actively considered suicide in the past year. CONCLUSION: Canadian EM physicians just before the COVID-19 pandemic had an alarming number of respondents meet the threshold for burnout, confirming EM as a high-risk specialty. This important baseline information can be used to monitor the physical and mental risks to EM physicians during and after COVID-19, and evaluate support for mental health and wellness, which is urgently needed now and post pandemic.


Assuntos
Esgotamento Profissional/epidemiologia , Esgotamento Profissional/prevenção & controle , Infecções por Coronavirus/epidemiologia , Saúde do Trabalhador , Estresse Ocupacional/epidemiologia , Médicos/psicologia , Pneumonia Viral/epidemiologia , Adulto , Canadá , Infecções por Coronavirus/prevenção & controle , Medicina de Emergência/estatística & dados numéricos , Serviço Hospitalar de Emergência/organização & administração , Feminino , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Pandemias/prevenção & controle , Pandemias/estatística & dados numéricos , Pneumonia Viral/prevenção & controle , Inquéritos e Questionários
6.
Neurology ; 95(4): e402-e412, 2020 07 28.
Artigo em Inglês | MEDLINE | ID: mdl-32554762

RESUMO

OBJECTIVE: To longitudinally assess brain microstructure and function in female varsity athletes participating in contact and noncontact sports. METHODS: Concussion-free female rugby players (n = 73) were compared to age-matched (ages 18-23) female swimmers and rowers (n = 31) during the in- and off-season. Diffusion and resting-state fMRI (rs-fMRI) measures were the primary outcomes. The Sports Concussion Assessment Tool and head impact accelerometers were used to monitor symptoms and impacts, respectively. RESULTS: We found cross-sectional (contact vs noncontact) and longitudinal (in- vs off-season) changes in white matter diffusion measures and rs-fMRI network connectivity in concussion-free contact athletes relative to noncontact athletes. In particular, mean, axial, and radial diffusivities were increased with decreased fractional anisotropy in multiple white matter tracts of contact athletes accompanied with default mode and visual network hyperconnectivity (p < 0.001). Longitudinal diffusion changes in the brainstem between the in- and off-season were observed for concussion-free contact athletes only, with progressive changes observed in a subset of athletes over multiple seasons. Axial diffusivity was significantly lower in the genu and splenium of the corpus callosum in those contact athletes with a history of concussion. CONCLUSIONS: Together, these findings demonstrate longitudinal changes in the microstructure and function of the brain in otherwise healthy, asymptomatic athletes participating in contact sport. Further research to understand the long-term brain health and biological implications of these changes is required, in particular to what extent these changes reflect compensatory, reparative, or degenerative processes.


Assuntos
Atletas , Traumatismos em Atletas/fisiopatologia , Encéfalo/fisiopatologia , Futebol Americano/lesões , Adolescente , Traumatismos em Atletas/etiologia , Estudos Transversais , Feminino , Humanos , Estudos Longitudinais , Imagem por Ressonância Magnética/métodos , Neuroimagem/métodos , Adulto Jovem
7.
Biofabrication ; 12(4): 045016, 2020 08 10.
Artigo em Inglês | MEDLINE | ID: mdl-32598334

RESUMO

Understanding the pathophysiological processes of cartilage degradation requires adequate model systems to develop therapeutic strategies towards osteoarthritis (OA). Although different in vitro or in vivo models have been described, further comprehensive approaches are needed to study specific disease aspects. This study aimed to combine in vitro and in silico modeling based on a tissue-engineering approach using mesenchymal condensation to mimic cytokine-induced cellular and matrix-related changes during cartilage degradation. Thus, scaffold-free cartilage-like constructs (SFCCs) were produced based on self-organization of mesenchymal stromal cells (mesenchymal condensation) and (i) characterized regarding their cellular and matrix composition or secondly (ii) treated with interleukin-1ß (IL-1ß) and tumor necrosis factor α (TNFα) for 3 weeks to simulate OA-related matrix degradation. In addition, an existing mathematical model based on partial differential equations was optimized and transferred to the underlying settings to simulate the distribution of IL-1ß, type II collagen degradation and cell number reduction. By combining in vitro and in silico methods, we aimed to develop a valid, efficient alternative approach to examine and predict disease progression and effects of new therapeutics.

8.
Can J Anaesth ; 67(10): 1417-1423, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32394338

RESUMO

Symptom management and end-of-life care are core skills for all physicians, although in ordinary times many anesthesiologists have fewer occasions to use these skills. The current coronavirus disease (COVID-19) pandemic has caused significant mortality over a short time and has necessitated an increase in provision of both critical care and palliative care. For anesthesiologists deployed to units caring for patients with COVID-19, this narrative review provides guidance on conducting goals of care discussions, withdrawing life-sustaining measures, and managing distressing symptoms.


Assuntos
Infecções por Coronavirus/terapia , Cuidados Críticos/organização & administração , Pneumonia Viral/terapia , Assistência Terminal/organização & administração , Anestesiologistas/organização & administração , Anestesiologistas/normas , Competência Clínica , Infecções por Coronavirus/mortalidade , Cuidados Críticos/normas , Humanos , Cuidados Paliativos/organização & administração , Pandemias , Médicos/organização & administração , Médicos/normas , Pneumonia Viral/mortalidade , Assistência Terminal/normas , Suspensão de Tratamento
10.
Age Ageing ; 2020 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-32459301

RESUMO

BACKGROUND: Substitute decision-makers (SDMs) make decisions on behalf of patients who do not have capacity, in line with previously expressed wishes, values and beliefs. However, miscommunications and poor awareness of previous wishes often lead to inappropriate care. Increasing public preparedness to communicate on behalf of loved ones may improve care in patients requiring an SDM. METHODS: We conducted an online survey in January 2019 with a representative sample of the Canadian population. The primary outcome was self-reported preparedness to be an SDM. The secondary outcome was support for a high school curriculum on the role of SDMs. The effect of socio-demographics, known enablers and barriers to acting as an SDM, and attitudes towards a high school curriculum were assessed using multivariate analysis. RESULTS: Of 1,000 participants, 53.1% felt prepared to be an SDM, and 75.4% stated they understood their loved one's values. However, only 55.6% reported having had a meaningful conversation with their loved one about values and wishes, and only 61.7% reported understanding the SDM role. Engagement in advance care planning for oneself was low (23.1%). Age, experience, training and comfort with communication were associated with preparedness in our multivariate analysis. A high school curriculum was supported by 61.1% of respondents, with 28.3% neutral and 10.6% against it. INTERPRETATION: There is a gap between perceived and actual preparedness to be an SDM. Many report understanding their loved one's values yet have not asked them about wishes in illness or end of life. The majority of respondents support high school education to improve preparedness.

11.
Pflege ; 33(2): 93-104, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32208900

RESUMO

Psychosocial working conditions and symptoms of burnout in somatic and psychiatric nursing Abstract. Background: While mental workload and stress among nurses are generally well-documented, differences within the nursing profession have hardly been investigated so far. Aim: This study aims to examine the differences and associations between psychosocial working conditions and symptoms of burnout of nurses working in somatic and psychiatric settings. Methods: A cross-sectional study has been conducted with employees in one somatic and one psychiatric hospital (n = 576). The Copenhagen Psychosocial Questionnaire and the Copenhagen Burnout Inventory were used to assess psychosocial workloads and burnout symptoms. The data analysis was carried out by univariate, bivariate and multivariate (regression) analyses. Results: About 50 % of respondents report at least a moderate level of symptoms of burnout with somatic nurses more frequently affected. While quantitative and physical demands are higher in somatic nursing, psychiatric nurses have a higher degree of emotional demands, socialß = 0.33) in somatic nursing and emotional demands (ß = 0.29) in psychiatric nursing serve as strongest predictors of burnout symptoms. Conclusions: Findings suggest specific profiles of psychosocial workload in somatic and psychiatric nursing as well as a high need for differentiated approaches for occupational health promotion.


Assuntos
Esgotamento Profissional/psicologia , Recursos Humanos de Enfermagem no Hospital/psicologia , Enfermagem Psiquiátrica , Especialidades de Enfermagem , Carga de Trabalho/psicologia , Estudos Transversais , Humanos , Recursos Humanos de Enfermagem no Hospital/estatística & dados numéricos , Inquéritos e Questionários
13.
Clin J Sport Med ; 30(5): e130-e133, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30113967

RESUMO

OBJECTIVE: Test the hypotheses that (1) concussion in adolescents impairs autonomic neural control of heart rate (HR), and (2) HR reactivity improves with symptom resolution. DESIGN: Observational, case-control. PARTICIPANTS: Nineteen concussed adolescents (8 female adolescents; age 15 ± 2 years) and 16 healthy controls (6 female adolescents, age 15 ± 2 years). INTERVENTION: All participants performed an isometric handgrip (IHG) at 30% maximum voluntary contraction lasting 30 seconds. Heart rate (electrocardiogram) and hemodynamic responses (photoplethysmographic Finometer) were recorded from 30 seconds of baseline and the last 10 seconds of handgrip. MAIN OUTCOME MEASURES: The HR response (ΔHR) at the onset of moderate-intensity IHG using a mixed 1-way analysis of variance. RESULTS: A group × time interaction (P < 0.005) indicated that handgrip evoked a greater ΔHR among control participants (13 ± 10 beats/min) compared with concussed (6.4 ± 6.3 beats/min; group P = 0.63; time P < 0.001; d = 0.77). CONCLUSION: These preliminary results suggest that a concussion impairs the ability to elevate HR at the exercise onset and, given the nature of the task, this could be interpreted to reflect reduced ability to withdraw cardiovagal control. Therefore, the data support the hypothesis of neural cardiac dysregulation in adolescents diagnosed with concussion. CLINICAL RELEVANCE: The IHG test could aid concussion diagnosis and support return-to-play decisions.

14.
J Strength Cond Res ; 34(3): 708-716, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30946260

RESUMO

Versteegh, TH, Dickey, JP, Emery, CA, Fischer, LK, MacDermid, JC, and Walton, DM. Evaluating the effects of a novel neuromuscular neck training device on multiplanar static and dynamic neck strength: A pilot study. J Strength Cond Res 34(3): 708-716, 2020-The neck serves an important function in damping the transference of acceleration forces between the head and the trunk, such as that occurring during contact sports or motor vehicle collisions. An inability to adequately dissipate forces has been proposed as a potential mechanism for clinical conditions such as whiplash or concussion, but current approaches to neck training may not be targeting the correct mechanisms. The purpose of this study was to explore the training effect of a novel neuromuscular strengthening protocol on dynamic and static neck strength. This was a quasiexperimental pilot study design with intervention (n = 8) and control (n = 10) groups. The intervention group was trained (twice/week, ∼10 minutes, for 7 weeks) on a training device that uses self-generated centripetal force to create a dynamic rotational resistance. This protocol is intended to target the ability of the neck muscles to perform coordinated multiplanar plyometric contractions. Both groups also continued with traditional neck strengthening that included training on a straight-plane, isotonic, 4-way neck machine. Performance on the training device showed improvement after routine practice within 1 week, as evidenced by a trend toward increased peak speed in revolutions per minute (RPM). After 7 weeks, peak RPM increased from 122.8 (95% confidence interval [CI], 91.3-154.4) to 252.3 (95% CI, 241.5-263.1). There was also a large positive effect size (Hedge's d, 0.68) in isometric composite (multiplane) neck strength favoring the intervention group over the control group (difference, 20 N; 95% CI, -8 to 48). The largest magnitude strength improvement in a single plane was in axial rotation and also favored the intervention group over the control group (Hedge's d, 1.24; difference, 46 N; 95% CI, 9-83). Future studies should explore whether the dynamic training presented here could help reduce the risk of sports concussion, whiplash, or other head-neck trauma.


Assuntos
Força Muscular , Músculos do Pescoço/fisiologia , Treinamento de Resistência/métodos , Cabeça , Humanos , Masculino , Projetos Piloto , Exercício Pliométrico , Treinamento de Resistência/instrumentação , Rotação , Adulto Jovem
15.
Clin J Sport Med ; 30(5): e147-e149, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30969186

RESUMO

OBJECTIVE: To assess the predictive capability of the postconcussion symptom scale (PCSS) of the sport concussion assessment tool (SCAT) III to differentiate concussed and nonconcussed adolescents. DESIGN: Retrospective. SETTING: Tertiary. PARTICIPANTS: Sixty-nine concussed (15.2 ± 1.6 years old) and 55 control (14.4 ± 1.7 years old) adolescents. INDEPENDENT VARIABLES: Postconcussion symptom scale. MAIN OUTCOME MEASURE: Two-proportion z-test determined differences in symptom endorsement between groups. To assess the predictive power of the PCSS, we trained an ensemble classifier composed of a forest of 1000 decision trees to classify subjects as concussed, or not concussed, based on PCSS responses. The initial classifier was trained on all 22-concussion symptoms addressed in the PCSS, whereas the second classifier removed concussion symptoms that were not statistically significant between groups. RESULTS: Concussion symptoms common between groups were trouble falling asleep, more emotional, irritability, sadness, and anxious. After removal, analysis of the second classifier indicated that the 5 leading feature rankings of symptoms were headache, head pressure, light sensitivity, noise sensitivity, and "don't feel right," which accounted for 52% of the variance between groups. CONCLUSIONS: Collectively, self-reported symptoms through the PCSS can differentiate concussed and nonconcussed adolescents. However, predictability for adolescent patients may be improved by removing emotional and sleep domain symptoms.

16.
Eur J Cell Biol ; 98(5-8): 151046, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31677819

RESUMO

CRN2 is an actin filament binding protein involved in the regulation of various cellular processes including cell migration and invasion. CRN2 has been implicated in the malignant progression of different types of human cancer. We used CRN2 knock-out mice for analyses as well as for crossbreeding with a Tp53/Pten knock-out glioblastoma mouse model. CRN2 knock-out mice were subjected to a phenotyping screen at the German Mouse Clinic. Murine glioblastoma tissue specimens as well as cultured murine brain slices and glioblastoma cell lines were investigated by immunohistochemistry, immunofluorescence, and cell biological experiments. Protein interactions were studied by immunoprecipitation, pull-down, and enzyme activity assays. CRN2 knock-out mice displayed neurological and behavioural alterations, e.g. reduced hearing sensitivity, reduced acoustic startle response, hypoactivity, and less frequent urination. While glioblastoma mice with or without the additional CRN2 knock-out allele exhibited no significant difference in their survival rates, the increased levels of CRN2 in transplanted glioblastoma cells caused a higher tumour cell encasement of murine brain slice capillaries. We identified two important factors of the tumour microenvironment, the tissue inhibitor of matrix metalloproteinase 4 (TIMP4) and the matrix metalloproteinase 14 (MMP14, synonym: MT1-MMP), as novel binding partners of CRN2. All three proteins mutually interacted and co-localised at the front of lamellipodia, and CRN2 was newly detected in exosomes. On the functional level, we demonstrate that CRN2 increased the secretion of TIMP4 as well as the catalytic activity of MMP14. Our results imply that CRN2 represents a pro-invasive effector within the tumour cell microenvironment of glioblastoma multiforme.


Assuntos
Glioblastoma/metabolismo , Metaloproteinase 14 da Matriz/metabolismo , Proteínas dos Microfilamentos/metabolismo , Inibidores Teciduais de Metaloproteinases/metabolismo , Animais , Glioblastoma/diagnóstico por imagem , Camundongos , Camundongos Knockout , Proteínas dos Microfilamentos/deficiência , Células Tumorais Cultivadas , Microambiente Tumoral
18.
CMAJ Open ; 7(3): E573-E581, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31530581

RESUMO

BACKGROUND: When a patient is incapable of making medical decisions for him- or herself, a substitute decision-maker makes choices according to the patient's previously expressed wishes, values and beliefs; however, little is known about public readiness to act as a substitute decision-maker in Canada. Our primary objective was to measure public self-reported preparedness to act as a substitute decision-maker, and explore the attitudes, barriers and enablers associated with preparedness. METHODS: From November 2017 to June 2018, we conducted a mixed-methods street intercept survey at 12 pedestrian areas in Ottawa, Ontario. We used descriptive statistics and logistic regression analysis to assess predictors of perceived preparedness to be a substitute decision-maker and determine support for high school education. We analyzed qualitative interview questions using inductive thematic analysis. RESULTS: Of the 626 eligible respondents, 196 refused to participate, leaving 430 participants (response rate 68.7%). A total of 404 surveys (94.0%) were fully complete with no missing data. The respondents were mostly female (243 [56.5%]) and residents of Ontario (364 [84.6%]). The average age was 33.9 years. Although 314 respondents (73.0%) felt prepared to be a substitute decision-maker, 194 (45.1%) reported never having had meaningful conversations with loved ones to understand their wishes in the event of critical illness. A total of 293 participants (68.1%) identified important barriers to feeling prepared. Most respondents (309 [71.9%]) agreed that high school students should learn about being a substitute decision-maker, citing age appropriateness, potential societal benefit and improved decision-making, while cautioning the need to respect different maturity levels, cultures and experiences. INTERPRETATION: he lack of conversation between loved ones reveals a gap between perceived and actual preparedness to be a substitute decision-maker for a loved one with a critical illness. The overall acceptability of high school education warrants further exploration.

19.
Analyst ; 144(15): 4653-4660, 2019 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-31257367

RESUMO

In this work, we introduce a high-throughput quantitative multi-element method for biological fluids enabled by omitting sample preparation and an analysis time of a few seconds per sample. For the first time, flow injection of an undiluted cerebrospinal fluid (CSF) was combined to state-of-the-art ICP-TOFMS detection for multi-element analysis. Owing to the low sample volume and trace element concentrations of the CSF, flow injection methods with only 5 µL sample intake were used in combination with an icpTOF 2R TOF-based ICP-MS instrument. Due to the lack of certified reference materials for CSF analysis, a validated method employing open vessel digestion of the CSF material in combination with ICP-sectorfield-MS analysis was carried out and used as a reference. Additionally, the performance of the flow injection ICP-TOFMS was cross-validated by flow injection quadrupole-based ICP-MS/MS analysis using both external calibration and isotope dilution strategies. In the latter case, the sample had to be injected several times because of the need for tailored gas conditions for different elements. Overall, flow injection of biological fluids delivered quantitative values, which were in excellent agreement with the gold standard established by ICP-SFMS demonstrating the capability of ICP-TOFMS analysis in terms of resolution and sensitivity for the accurate quantification of trace elements in biological samples.


Assuntos
Espectrometria de Massas em Tandem/métodos , Oligoelementos/líquido cefalorraquidiano , Animais , Calibragem , Análise de Injeção de Fluxo/métodos , Humanos , Limite de Detecção , Oligoelementos/sangue
20.
Clin J Sport Med ; 2019 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-30908327

RESUMO

OBJECTIVE: To study autonomic responses to postural changes in concussed adolescents. The influence of sex was also studied. DESIGN: Longitudinal cohort observational study. PARTICIPANTS: Concussed adolescents (CONC; n = 65; 26 male adolescents; age 15 ± 1 years, range = 12-18 years) and a control (CTRL) group of nonconcussed adolescents of similar age and sport (CTRL; n = 54; 29 male adolescents; age 14 ± 1 years, range = 12-18 years). INTERVENTIONS: Concussed participants were monitored through 6 weekly visits throughout usual physician care. Control participants underwent 2 visits separated by at least 1 week to account for intrapersonal variation in testing measures. MAIN OUTCOME MEASURES: Heart rate variability as the root mean square of successive differences in R-R intervals (RMSSD), heart rate (HR), and blood pressure [mean arterial pressure (MAP) and diastolic blood pressure (DBP)] were measured in supine, sitting, and standing postures. RESULTS: A mixed analysis of variance revealed a group × sex × posture interaction (P = 0.04) where seated values of RMSSD were less in concussed female participants versus control female participants (42 ± 4 vs 61 ± 7 ms; P = 0.01; Mann-Whitney rank test). Compared with CTRL, CONC exhibited increased pretesting seated DBP (69 ± 1 vs 74 ± 1 mm Hg; P < 0.01), MAP (83 ± 1 vs 86 ± 1 mm Hg; P = 0.02), and baseline seated HR (72 ± 1 vs 77 ± 2 bpm; P = 0.03). Values of DBP (P = 0.03) and MAP (P < 0.01) improved at clinical discharge, whereas the RMSSD in female participants did not (P > 0.5). Data are mean ± SEM. CONCLUSIONS: A modest reduction in female cardiac autonomic regulation was observed during seated postures. Alterations in seated concussed DBP and MAP, but not RMSSD, resolved at clinical discharge (median = 37 days). The results indicate that, in adolescents, concussion may impair cardiovagal function in a sex- and posture-dependent manner. The findings also suggest that BP metrics, but not RMSSD, are associated with clinical concussion recovery.This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal.

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