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1.
New Phytol ; 231(5): 1798-1813, 2021 09.
Artículo en Inglés | MEDLINE | ID: mdl-33993520

RESUMEN

Deep-water access is arguably the most effective, but under-studied, mechanism that plants employ to survive during drought. Vulnerability to embolism and hydraulic safety margins can predict mortality risk at given levels of dehydration, but deep-water access may delay plant dehydration. Here, we tested the role of deep-water access in enabling survival within a diverse tropical forest community in Panama using a novel data-model approach. We inversely estimated the effective rooting depth (ERD, as the average depth of water extraction), for 29 canopy species by linking diameter growth dynamics (1990-2015) to vapor pressure deficit, water potentials in the whole-soil column, and leaf hydraulic vulnerability curves. We validated ERD estimates against existing isotopic data of potential water-access depths. Across species, deeper ERD was associated with higher maximum stem hydraulic conductivity, greater vulnerability to xylem embolism, narrower safety margins, and lower mortality rates during extreme droughts over 35 years (1981-2015) among evergreen species. Species exposure to water stress declined with deeper ERD indicating that trees compensate for water stress-related mortality risk through deep-water access. The role of deep-water access in mitigating mortality of hydraulically-vulnerable trees has important implications for our predictive understanding of forest dynamics under current and future climates.


Asunto(s)
Sequías , Árboles , Bosques , Hojas de la Planta , Agua , Abastecimiento de Agua , Xilema
2.
Oecologia ; 186(4): 1127-1135, 2018 04.
Artículo en Inglés | MEDLINE | ID: mdl-29411110

RESUMEN

In resource-limited savannas, the distribution and abundance of fine roots play an important role in acquiring essential resources and structuring vegetation patterns and dynamics. However, little is known regarding the three-dimensional distribution of fine roots in savanna ecosystems at the landscape scale. We quantified spatial patterns of fine root density to a depth of 1.2 m in a subtropical savanna landscape using spatially specific sampling. Kriged maps revealed that fine root density was highest at the centers of woody patches, decreased towards the canopy edges, and reached lowest values within the grassland matrix throughout the entire soil profile. Lacunarity analyses indicated that spatial heterogeneities of fine root density decreased continuously to a depth of 50 cm and then increased in deeper portions of the soil profile across this landscape. This vertical pattern might be related to inherent differences in root distribution between trees/shrubs and herbaceous species, and the presence/absence of an argillic horizon across this landscape. The greater density of fine roots beneath woody patches in both upper and lower portions of the soil profile suggests an ability to acquire disproportionately more resources than herbaceous species, which may facilitate the development and persistence of woody patches across this landscape.


Asunto(s)
Ecosistema , Pradera , Suelo , Árboles , Madera
3.
Arch Phys Med Rehabil ; 98(9): 1806-1811, 2017 09.
Artículo en Inglés | MEDLINE | ID: mdl-28137476

RESUMEN

OBJECTIVE: To establish the minimal detectable change (MDC) and minimal clinically important difference (MCID) for the Cumberland Ankle Instability Tool (CAIT) in a population with chronic ankle instability (CAI). DESIGN: Experimental cohort. SETTING: Laboratory. PARTICIPANTS: A convenience sample of individuals with CAI (N=50; 12 men; 38 women; episodes of giving way, 5.84±12.54mo). CAI inclusion criteria included a history of an ankle sprain, recurrent episodes of giving way, and a CAIT score ≤25. INTERVENTIONS: Participants completed demographic information, an injury history questionnaire, and the CAIT. Participants then either participated in 4 weeks of wobble board balance training, resistance tubing strength training, or no intervention. After 4 weeks, participants recompleted the CAIT and recorded their global rating of change (GRC). MAIN OUTCOME MEASURES: Dependent variables were pre- and postintervention scores on the CAIT and postintervention GRC. The MDC with 95% confidence interval was calculated. A receiver operating characteristic (ROC) curve identified the optimal CAIT cut point (MCID) between improved and unimproved individuals on the basis of their GRC. The area under the curve was used to identify a significant ROC curve (α=.05). RESULTS: The average CAIT score preintervention was 16.8±5.6, and postintervention, it was 20.0±5.2. Thirty-one participants (62%) rated themselves as improved on the GRC scale, whereas 19 (38%) were not improved. The ROC curve was significant (area under the curve, .797; P=.001), indicating that the CAIT change score significantly predicted clinical status. The MDC was 3.08, and the MCID was ≥3 points. CONCLUSIONS: The CAIT has an MDC and MCID of ≥3 points. When CAIT scores are used to assess patient change over time, these scores should be used as a minimum threshold to indicate detectable and clinically meaningful improvement.


Asunto(s)
Traumatismos del Tobillo/fisiopatología , Inestabilidad de la Articulación/fisiopatología , Diferencia Mínima Clínicamente Importante , Índice de Severidad de la Enfermedad , Evaluación de Síntomas/normas , Adolescente , Adulto , Traumatismos del Tobillo/terapia , Articulación del Tobillo/fisiopatología , Evaluación de la Discapacidad , Femenino , Humanos , Inestabilidad de la Articulación/terapia , Masculino , Estándares de Referencia , Encuestas y Cuestionarios , Evaluación de Síntomas/métodos , Adulto Joven
4.
J Sport Rehabil ; 26(4): 250-256, 2017 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-27834579

RESUMEN

OBJECTIVE: To track the patient-reported efficacy of a 4-wk intervention (wobble board [WB] or resistance tubing [RT]) in decreasing symptoms of chronic ankle instability (CAI) at 6 mo postintervention (6PI) as compared with immediately postintervention (IPI). DESIGN: Randomized controlled trial. PARTICIPANTS: Fourteen of 21 participants (66.7%) responded to an electronic 6-m follow-up questionnaire (age 19.6 ± 0.9 y, height 1.63 ± 0.18 m, weight 70.5 ± 16.3 kg; 2 male, 12 female; 5 WB, 9 RT). All participants met CAI criteria at enrollment, including a history of ankle sprain and recurrent episodes of giving way. INTERVENTIONS: Participants completed either RT or WB protocols, both 12 sessions over 4 wk of progressive exercise. WB sessions consisted of five 40-s sets of clockwise and counterclockwise rotations. RT sessions consisted of 30 contractions against resistance tubing in each of 4 ankle directions. MAIN OUTCOME MEASUREMENTS: Patient-reported symptoms of "giving way" preintervention and at 6PI, global rating of change (GRC) frequencies at IPI and 6PI, and resprains at 6PI were reported descriptively. Changes in global rating of function (GRF) and giving way were compared using Wilcoxon tests, while GRC was compared with Fisher exact test. RESULTS: All participants reported giving way preintervention, only 57.1% reported giving way at 6PI. Resprains occurred in 21.4% of participants. Giving-way frequency (P = .017), but not GRF or GRC (P > .05), was significantly different at IPI vs 6PI. CONCLUSIONS: Simple 4-wk interventions maintained some but not all improvements at 6PI. At least 42.9% of participants would no longer meet the current study's CAI inclusion criteria due to a reduction in giving way.


Asunto(s)
Inestabilidad de la Articulación/rehabilitación , Medición de Resultados Informados por el Paciente , Equilibrio Postural , Entrenamiento de Fuerza , Tobillo/fisiopatología , Articulación del Tobillo/fisiopatología , Enfermedad Crónica , Femenino , Humanos , Inestabilidad de la Articulación/fisiopatología , Masculino , Resultado del Tratamiento , Adulto Joven
5.
J Sport Rehabil ; 26(4): 238-249, 2017 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-27632874

RESUMEN

CONTEXT: There is minimal patient-oriented evidence regarding the effectiveness of interventions targeted to reduce symptoms associated with chronic ankle instability (CAI). In addition, clinicians aiming to prioritize care by implementing only the most effective components of a rehabilitative program have very little evidence on comparative efficacy. OBJECTIVE: To assess the comparative efficacy of 2 common ankle rehabilitation techniques (wobble-board [WB] balance training and ankle strengthening using resistance tubing [RT]) using patient-oriented outcomes. DESIGN: Randomized controlled trial. SETTING: Laboratory. PATIENTS: 40 patients with CAI randomized into 2 treatment groups: RT and WB. CAI inclusion criteria included a history of an ankle sprain, recurrent "giving way," and a Cumberland Ankle Instability Tool (CAIT) score ≤25. INTERVENTIONS: Participants completed 5 clinician-oriented tests (foot-lift test, time-in-balance, Star Excursion Balance Test, figure-of-8 hop, and side-hop) and 5 patient-oriented questionnaires (CAIT, Foot and Ankle Ability Measure [FAAM], Activities of Daily Living [ADL] and FAAM Sport scale, Short-Form 36 [SF-36], and Global Rating of Function [GRF]). After baseline testing, participants completed 12 sessions over 4 wk of graduated WB or RT exercise, then repeated baseline tests. MAIN OUTCOME MEASURES: For each patient- and clinician-oriented test, separate 2 × 2 RMANOVAs analyzed differences between groups over time (alpha set at P = .05). RESULTS: There was a significant interaction between group and time for the FAAM-ADL (P = .04). Specifically, the WB group improved postintervention (P < .001) whereas the RT group remained the same (P = .29). There were no other significant interactions or significant differences between groups (all P > .05). There were significant improvements postintervention for the CAIT, FAAM-Sport, GRF, SF-36, and all 5 clinician-oriented tests (all P < .001). CONCLUSIONS: A single-exercise 4-wk intervention can improve patient- and clinician-oriented outcomes in individuals with CAI. Limited evidence indicates that WB training was more effective than RT. LEVEL OF EVIDENCE: Therapy, level 1b.


Asunto(s)
Inestabilidad de la Articulación/rehabilitación , Medición de Resultados Informados por el Paciente , Equilibrio Postural , Entrenamiento de Fuerza , Adolescente , Adulto , Tobillo/fisiopatología , Traumatismos del Tobillo/fisiopatología , Traumatismos del Tobillo/rehabilitación , Articulación del Tobillo/fisiopatología , Enfermedad Crónica , Femenino , Humanos , Inestabilidad de la Articulación/fisiopatología , Masculino , Fuerza Muscular , Resultado del Tratamiento , Adulto Joven
6.
Eur J Immunol ; 45(8): 2232-42, 2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-26018465

RESUMEN

Both the recognition of HIV-infected cells and the immunogenicity of candidate CTL vaccines depend on the presentation of a peptide epitope at the cell surface, which in turn depends on intracellular antigen processing. Differential antigen processing maybe responsible for the differences in both the quality and the quantity of epitopes produced, influencing the immunodominance hierarchy of viral epitopes. Previously, we showed that the magnitude of the HIV-2 gag-specific T-cell response is inversely correlated with plasma viral load, particularly when responses are directed against an epitope, 165 DRFYKSLRA173 , within the highly conserved Major Homology Region of gag-p26. We also showed that the presence of three proline residues, at positions 119, 159 and 178 of gag-p26, was significantly correlated with low viral load. Since this proline motif was also associated with stronger gag-specific CTL responses, we investigated the impact of these prolines on proteasomal processing of the protective 165 DRFYKSLRA173 epitope. Our data demonstrate that the 165 DRFYKSLRA173 epitope is most efficiently processed from precursors that contain two flanking proline residues, found naturally in low viral-load patients. Superior antigen processing and enhanced presentation may account for the link between infection with HIV-2 encoding the "PPP-gag" sequence and both strong gag-specific CTL responses as well as lower viral load.


Asunto(s)
Epítopos de Linfocito T/inmunología , Infecciones por VIH/inmunología , VIH-2/inmunología , Inmunidad Celular , Linfocitos T/inmunología , Productos del Gen gag del Virus de la Inmunodeficiencia Humana/inmunología , Secuencias de Aminoácidos , Epítopos de Linfocito T/genética , Femenino , Infecciones por VIH/genética , Infecciones por VIH/patología , VIH-2/genética , Humanos , Masculino , Linfocitos T/patología , Carga Viral/inmunología , Productos del Gen gag del Virus de la Inmunodeficiencia Humana/genética
7.
Mol Cell Proteomics ; 11(2): M9.00384, 2012 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-22311593

RESUMEN

Ankylosing spondylitis (AS) is a common, inflammatory rheumatic disease that primarily affects the axial skeleton and is associated with sacroiliitis, uveitis, and enthesitis. Unlike other autoimmune rheumatic diseases, such as rheumatoid arthritis or systemic lupus erythematosus, autoantibodies have not yet been reported to be a feature of AS. We therefore wished to determine whether plasma from patients with AS contained autoantibodies and, if so, characterize and quantify this response in comparison to patients with rheumatoid arthritis (RA) and healthy controls. Two high density nucleic acid programmable protein arrays expressing a total of 3498 proteins were screened with plasma from 25 patients with AS, 17 with RA, and 25 healthy controls. Autoantigens identified were subjected to Ingenuity Pathway Analysis to determine the patterns of signaling cascades or tissue origin. 44% of patients with ankylosing spondylitis demonstrated a broad autoantibody response, as compared with 33% of patients with RA and only 8% of healthy controls. Individuals with AS demonstrated autoantibody responses to shared autoantigens, and 60% of autoantigens identified in the AS cohort were restricted to that group. The autoantibody responses in the AS patients were targeted toward connective, skeletal, and muscular tissue, unlike those of RA patients or healthy controls. Thus, patients with AS show evidence of systemic humoral autoimmunity and multispecific autoantibody production. Nucleic acid programmable protein arrays constitute a powerful tool to study autoimmune diseases.


Asunto(s)
Autoanticuerpos/sangre , Autoantígenos/inmunología , Ácidos Nucleicos/química , Análisis por Matrices de Proteínas , Espondilitis Anquilosante/diagnóstico , Espondilitis Anquilosante/inmunología , Adolescente , Adulto , Anciano , Autoanticuerpos/inmunología , Estudios de Casos y Controles , Femenino , Humanos , Masculino , Persona de Mediana Edad , Pronóstico , Proteoma/análisis , Espondilitis Anquilosante/sangre , Adulto Joven
8.
Mol Cell Proteomics ; 11(2): M111.013904, 2012 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-21997733

RESUMEN

Ankylosing Spondylitis (AS) is a common inflammatory rheumatic disease with a predilection for the axial skeleton, affecting 0.2% of the population. Current diagnostic criteria rely on a composite of clinical and radiological changes, with a mean time to diagnosis of 5 to 10 years. In this study we employed nano liquid-chromatography mass spectrometry analysis to detect and quantify proteins and small compounds including endogenous peptides and metabolites in serum from 18 AS patients and nine healthy individuals. We identified a total of 316 proteins in serum, of which 22 showed significant up- or down-regulation (p < 0.05) in AS patients. Receiver operating characteristic analysis of combined levels of serum amyloid P component and inter-α-trypsin inhibitor heavy chain 1 revealed high diagnostic value for Ankylosing Spondylitis (area under the curve = 0.98). We also depleted individual sera of proteins to analyze endogenous peptides and metabolic compounds. We detected more than 7000 molecular features in patients and healthy individuals. Quantitative MS analysis revealed compound profiles that correlate with the clinical assessment of disease activity. One molecular feature identified as a Vitamin D3 metabolite-(23S,25R)-25-hydroxyvitamin D3 26,23-peroxylactone-was down-regulated in AS. The ratio of this vitamin D metabolite versus vitamin D binding protein serum levels was also altered in AS as compared with controls. These changes may contribute to pathological skeletal changes in AS. Our study is the first example of an integration of proteomic and metabolomic techniques to find new biomarker candidates for the diagnosis of Ankylosing Spondylitis.


Asunto(s)
Biomarcadores/análisis , Proteínas Sanguíneas/metabolismo , Metabolómica , Proteómica , Espondilitis Anquilosante/diagnóstico , Adolescente , Adulto , Anciano , Estudios de Casos y Controles , Cromatografía Liquida , Femenino , Humanos , Masculino , Persona de Mediana Edad , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Espondilitis Anquilosante/sangre
9.
Arch Phys Med Rehabil ; 95(10): 1853-9, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-24814563

RESUMEN

OBJECTIVE: To independently recalibrate and revalidate the Cumberland Ankle Instability Tool (CAIT) cutoff score for discriminating individuals with and without chronic ankle instability (CAI). There are concerns the original cutoff score (≤27) may be suboptimal for use in the CAI population. DESIGN: Case control. SETTING: Research laboratory. PARTICIPANTS: Two independent datasets were used (total N=200). Dataset 1 included 61 individuals with a history of ≥1 ankle sprain and ≥2 episodes of giving way in the last year (CAI group) and 57 participants with no history of ankle sprain or instability in their lifetime (uninjured group). Dataset 2 included 27 uninjured participants, 29 participants with CAI, and 26 individuals with a history of a single ankle sprain and no subsequent instability (copers). INTERVENTIONS: All participants completed the CAIT during a single session. In dataset 1, a receiver operating characteristic (ROC) curve was calculated using the CAIT score and group membership as test variables. The ideal cutoff score was identified using the Youden index. The recalibrated cutoff score was validated in dataset 2 using the ROC analysis and clinimetric characteristics. MAIN OUTCOME MEASURES: CAIT cutoff score and clinimetrics. RESULTS: In dataset 1, the optimal cutoff score was ≤25, which is lower than previously reported. In dataset 2, the recalibrated cutoff score demonstrated a sensitivity of 96.6%, specificity of 86.8%, positive likelihood ratio of 7.318, and negative likelihood ratio of .039. There were 7 false positives and 1 false negative. CONCLUSIONS: The recalibrated CAIT score demonstrated very good clinimetric properties; all properties improved compared with the original cutoff score. Clinicians using the CAIT should use the recalibrated cutoff score to maximize test characteristics. Caution should be taken with copers, who had a high rate of false positives.


Asunto(s)
Traumatismos del Tobillo/complicaciones , Inestabilidad de la Articulación/diagnóstico , Esguinces y Distensiones/complicaciones , Adulto , Área Bajo la Curva , Calibración , Estudios de Casos y Controles , Enfermedad Crónica , Técnicas de Apoyo para la Decisión , Reacciones Falso Negativas , Reacciones Falso Positivas , Femenino , Humanos , Inestabilidad de la Articulación/etiología , Masculino , Curva ROC , Índice de Severidad de la Enfermedad , Adulto Joven
10.
J Athl Train ; 59(4): 419-427, 2024 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-38116808

RESUMEN

CONTEXT: Over the past decade, the United States military has taken an interest in addressing soldiers' spiritual fitness and readiness to help improve their mental health and resiliency. Similar efforts have not been applied within the Reserve Officers' Training Corps (ROTC) population despite the mental health challenges these college students experience. OBJECTIVE: To examine spiritual readiness, spiritual fitness, and depressive symptoms in ROTC cadets. DESIGN: Cross-sectional study. SETTING: Web-based survey. PATIENTS OR OTHER PARTICIPANTS: We recruited ROTC cadets from 1 large southeastern university (n = 91 of 315, 28.9% response rate). The ROTC cadets (age = 21 ± 3 years; men = 68, 74.7%; women = 22, 24.2%; missing = 1, 1.1%) were mainly classified as juniors (n = 30, 33.0%) and in Army ROTC (ROTC branch: Army = 69, Air Force = 20, Navy = 2). MAIN OUTCOME MEASURE(S): The survey contained 3 validated instruments used to assess spiritual fitness (the Spiritual Fitness Inventory [SFI]), spiritual readiness (Spiritual Wellbeing Scale [SWBS]), and mental health via depressive symptoms (Patient Health Questionnaire [PHQ-9]). Results were analyzed using descriptive statistics and nonparametric Mann-Whitney U tests to compare belief in God or gods with the dependent measures. A Pearson correlation was calculated to assess the relationship between the SWBS score and PHQ-9 data. RESULTS: In total, 85.7% (n = 78/91) of ROTC cadets stated that they believed in God or gods. Overall, the cadets were considered to have average spiritual fitness (mean = 75.04 ± 14.89) and moderate spiritual well-being (mean = 90.46 ± 18.09). The average PHQ-9 score was 4.22 ± 5.25. Individuals who believed in God or gods had higher spiritual readiness (believer = 94.44 ± 16.10, nonbeliever = 67.00 ± 9.35; P ≤ .01). No statistically significant differences were noted for symptoms of depression (believer = 3.38 ± 4.90, nonbeliever = 6.60 ± 6.90; P = .143) or spiritual fitness (believer = 76.12 ± 14.78, nonbeliever = 64.40 ± 12.68; P = .054) in ROTC cadets based on belief status. CONCLUSIONS: Overall, the ROTC cadets had moderate to average spiritual fitness and readiness, with typical depressive symptoms scores. Spiritual readiness was different for those who believed in God or gods, and existential well-being was significantly correlated with depressive symptoms.


Asunto(s)
Depresión , Personal Militar , Espiritualidad , Humanos , Masculino , Femenino , Depresión/psicología , Personal Militar/psicología , Estudios Transversales , Adulto Joven , Encuestas y Cuestionarios , Salud Mental , Adulto , Estudiantes/psicología , Estados Unidos , Adolescente , Universidades
11.
Tree Physiol ; 44(1)2024 02 06.
Artículo en Inglés | MEDLINE | ID: mdl-37935389

RESUMEN

In forest ecosystems, transpiration (T) patterns are important for quantifying water and carbon fluxes and are major factors in predicting ecosystem change. Seasonal changes in rainfall and soil water content can alter the sensitivity of sap flux density to daily variations in vapor pressure deficit (VPD). This sensitivity is species-specific and is thought to be related to hydraulic strategies. The aim of this work is to better understand how the sap flux density of species with low versus high wood density differ in their sensitivity to VPD and soil water content and how potentially opposing water-use strategies influence T dynamics, and ultimately, correlations to evapotranspiration (ET). We use hysteresis area analysis to quantify the sensitivity of species-specific sap flux density to changes in the VPD, breakpoint-based models to determine the soil water content threshold instigating a T response and multiscalar wavelet coherency to correlate T to ET. We found that low wood density Commiphora leptophloeos (Mart.) Gillett had a more dynamic T pattern, a greater sensitivity to VPD at high soil water content, required a higher soil water content threshold for this sensitivity to be apparent, and had a significant coherency correlation with ET at daily to monthly timescales. This behavior is consistent with a drought avoidance strategy. High wood density Cenostigma pyramidale  (Tul.)  E. Gagnon & G. P. Lewis, conversely, had a more stable T pattern, responded to VPD across a range of soil water content, tolerated a lower soil water content threshold to T, and had a significant coherency correlation with ET at weekly timescales. This behavior is consistent with a drought-tolerant strategy. We build on previous research to show that these species have contrasting water-use strategies that should be considered in large-scale modeling efforts.


Asunto(s)
Ecosistema , Agua , Agua/análisis , Árboles/fisiología , Bosques , Suelo , Transpiración de Plantas/fisiología
12.
Acad Med ; 99(5): 493-499, 2024 05 01.
Artículo en Inglés | MEDLINE | ID: mdl-38166321

RESUMEN

ABSTRACT: Outcome data from 6 National Institutes of Health-funded Postbaccalaureate Research Education Programs (PREPs) in the Mid-Atlantic region were combined to give a multi-institutional perspective on their scholars' characteristics and progress through biomedical research training. The institutions hosting these programs were Johns Hopkins University School of Medicine, the Medical University of South Carolina, the University of Maryland School of Medicine, the University of North Carolina at Chapel Hill, Virginia Commonwealth University, and Virginia Polytechnic Institute and State University. The authors summarize the institutional pathways, demographics, undergraduate institutions, and graduate institutions for a total of 384 PREP scholars who completed the programs by June 2021. A total of 228 (59.4%) of these PREP scholars identified as Black or African American, 116 (30.2%) as Hispanic or Latinx, and 269 (70.0%) as female. The authors found that 376 of 384 scholars (97.9%) who started PREP finished their program, 319 of 376 (84.8%) who finished PREP matriculated into PhD or MD/PhD programs, and 284 of 319 (89.0%) who matriculated have obtained their PhD or are successfully making progress toward their PhD.


Asunto(s)
Investigación Biomédica , Adulto , Femenino , Humanos , Masculino , Negro o Afroamericano/estadística & datos numéricos , Hispánicos o Latinos/estadística & datos numéricos , Evaluación de Programas y Proyectos de Salud , Facultades de Medicina/organización & administración , South Carolina , Estados Unidos , Universidades
13.
PLoS Pathog ; 7(5): e1001341, 2011 May.
Artículo en Inglés | MEDLINE | ID: mdl-21589893

RESUMEN

A major challenge to developing a successful HIV vaccine is the vast diversity of viral sequences, yet it is generally assumed that an epitope conserved between different strains will be recognised by responding T-cells. We examined whether an invariant HLA-B8 restricted Nef90₋97 epitope FL8 shared between five high titre viruses and eight recombinant vaccinia viruses expressing Nef from different viral isolates (clades A-H) could activate antiviral activity in FL8-specific cytotoxic T-lymphocytes (CTL). Surprisingly, despite epitope conservation, we found that CTL antiviral efficacy is dependent on the infecting viral isolate. Only 23% of Nef proteins, expressed by HIV-1 isolates or as recombinant vaccinia-Nef, were optimally recognised by CTL. Recognition of the HIV-1 isolates by CTL was independent of clade-grouping but correlated with virus-specific polymorphisms in the epitope flanking region, which altered immunoproteasomal cleavage resulting in enhanced or impaired epitope generation. The finding that the majority of virus isolates failed to present this conserved epitope highlights the importance of viral variance in CTL epitope flanking regions on the efficiency of antigen processing, which has been considerably underestimated previously. This has important implications for future vaccine design strategies since efficient presentation of conserved viral epitopes is necessary to promote enhanced anti-viral immune responses.


Asunto(s)
Epítopos de Linfocito T/genética , VIH-1/inmunología , Complejo de la Endopetidasa Proteasomal/fisiología , Linfocitos T Citotóxicos/inmunología , Productos del Gen nef del Virus de la Inmunodeficiencia Humana/inmunología , Vacunas contra el SIDA/normas , Secuencia de Aminoácidos , Presentación de Antígeno/genética , Secuencia Conservada , ADN Viral/química , ADN Viral/genética , Ensayo de Immunospot Ligado a Enzimas , Epítopos de Linfocito T/fisiología , Antígenos VIH/metabolismo , Infecciones por VIH/inmunología , Infecciones por VIH/prevención & control , Infecciones por VIH/virología , VIH-1/genética , VIH-1/metabolismo , Antígeno HLA-B8/metabolismo , Humanos , Interferón gamma/metabolismo , Datos de Secuencia Molecular , Mutación , Polimorfismo Genético , Complejo de la Endopetidasa Proteasomal/inmunología , Análisis de Secuencia de ADN , Linfocitos T Citotóxicos/virología , Virus Vaccinia/genética , Productos del Gen nef del Virus de la Inmunodeficiencia Humana/genética , Productos del Gen nef del Virus de la Inmunodeficiencia Humana/metabolismo
14.
Foot Ankle Orthop ; 8(1): 24730114231160996, 2023 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37009417

RESUMEN

Background: Manuscripts discussing return to play (RTP) following ankle surgery are common. However, the definition for RTP and the method by which it is determined remains unclear. The purpose of this scoping review was to clarify how RTP is defined following ankle surgery in physically active patients, to identify key factors informing RTP decision making (such as objective clinical measures), and make recommendations for future research. Methods: A scoping literature review was performed in April 2021 using PubMed, EMBASE, and Nursing and Allied Health databases. Thirty studies met inclusion criteria: original research following ankle surgery reporting at least 1 objective clinical test and documentation of RTP. Data were extracted for study methods and outcomes (RTP definition, RTP outcomes, and objective clinical tests). Results: The scoping review found studies on 5 ankle pathologies: Achilles tendon rupture, chronic lateral ankle instability, anterior ankle impingement, peroneal tendon dislocation, and ankle fracture. RTP criteria were not provided in the majority of studies (18/30 studies). In the studies that provided them, the RTP criteria were primarily based on time postsurgery (8/12) rather than validated criteria. Objective clinical outcome measures and patient-reported outcome measures (PROMs) were documented for each surgery when available. Both clinical outcomes and PROMs were typically measured >1 year postsurgery. Conclusion: In physically active patients who have had ankle surgery, RTP remains largely undefined and is not consistently based on prospective objective criteria nor PROMS. We recommend standardization of RTP terminology, adoption of prospective criteria for both clinical measures and PROMs to guide RTP decision making, and enhanced reporting of patient data at the time of RTP to develop normative values and determine when the decision to RTP is not safe. Level of Evidence: Level IV, scoping review.

15.
Nat Ecol Evol ; 7(5): 687-697, 2023 05.
Artículo en Inglés | MEDLINE | ID: mdl-37069334

RESUMEN

We show that the high seas are colonized by a diverse array of coastal species, which survive and reproduce in the open ocean, contributing strongly to its floating community composition. Analysis of rafting plastic debris in the eastern North Pacific Subtropical Gyre revealed 37 coastal invertebrate taxa, largely of Western Pacific origin, exceeding pelagic taxa richness by threefold. Coastal taxa, including diverse taxonomic groups and life history traits, occurred on 70.5% of debris items. Most coastal taxa possessed either direct development or asexual reproduction, possibly facilitating long-term persistence on rafts. Our results suggest that the historical lack of available substrate limited the colonization of the open ocean by coastal species, rather than physiological or ecological constraints as previously assumed. It appears that coastal species persist now in the open ocean as a substantial component of a neopelagic community sustained by the vast and expanding sea of plastic debris.


Asunto(s)
Plásticos , Reproducción , Océanos y Mares , Reproducción Asexuada
16.
J Sport Rehabil ; 21(2): 127-36, 2012 May.
Artículo en Inglés | MEDLINE | ID: mdl-22104559

RESUMEN

CONTEXT: Force sense (FS), the proprioceptive ability to detect muscle-force generation, has been shown to be impaired in individuals with functional ankle instability (FAI). Fatigue can also impair FS in healthy individuals, but it is unknown how fatigue affects FS in individuals with FAI. OBJECTIVE: To assess the effect of fatigue on ankle-eversion force-sense error in individuals with and without FAI. DESIGN: Case control with repeated measures. SETTING: Sports medicine research laboratory. PARTICIPANTS: 32 individuals with FAI and 32 individuals with no ankle sprains or instability in their lifetime. FAI subjects had a history of ≥1 lateral ankle sprain and giving-way ≥1 episode per month. INTERVENTIONS: Three eversion FS trials were captured per load (10% and 30% of maximal voluntary isometric contraction) using a load cell before and after a concentric eversion fatigue protocol. MAIN OUTCOME MEASURES: Trial error was the difference between the target and reproduction forces. Constant error (CE), absolute error (AE), and variable error (VE) were calculated from 3 trial errors. A Group × Fatigue × Load repeated-measures ANOVA was performed for each error. RESULTS: There were no significant 3-way interactions or 2-way interactions involving group (all P > .05). CE and AE had a significant 2-way interaction between load and fatigue (CE: F1,62 = 8.704, P = .004; AE: F1,62 = 4.024, P = .049), and VE had a significant main effect for fatigue (F1,62 = 5.130, P = .027), all of which indicated increased FS error with fatigue at 10% load. However, at 30% load only VE increased with fatigue. The FAI group had greater error as measured by AE (F1,62 = 4.571, P = .036) but not CE or VE (P > .05). CONCLUSIONS: Greater AE indicates that FAI individuals are less accurate in their force production. Fatigue impaired force sense in all subjects equally. These deficits provide evidence of impaired proprioception with fatigue and in individuals with FAI.


Asunto(s)
Traumatismos del Tobillo/fisiopatología , Retroalimentación Sensorial/fisiología , Inestabilidad de la Articulación/fisiopatología , Fatiga Muscular/fisiología , Esguinces y Distensiones/fisiopatología , Adolescente , Adulto , Traumatismos del Tobillo/complicaciones , Articulación del Tobillo/fisiopatología , Estudios de Casos y Controles , Femenino , Humanos , Contracción Isométrica/fisiología , Inestabilidad de la Articulación/etiología , Masculino , Músculo Esquelético/fisiopatología , Esguinces y Distensiones/complicaciones , Adulto Joven
17.
Front Plant Sci ; 13: 825097, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35401584

RESUMEN

With current observations and future projections of more intense and frequent droughts in the tropics, understanding the impact that extensive dry periods may have on tree and ecosystem-level transpiration and concurrent carbon uptake has become increasingly important. Here, we investigate paired soil and tree water extraction dynamics in an old-growth upland forest in central Amazonia during the 2018 dry season. Tree water use was assessed via radial patterns of sap flow in eight dominant canopy trees, each a different species with a range in diameter, height, and wood density. Paired multi-sensor soil moisture probes used to quantify volumetric water content dynamics and soil water extraction within the upper 100 cm were installed adjacent to six of those trees. To link depth-specific water extraction patterns to root distribution, fine root biomass was assessed through the soil profile to 235 cm. To scale tree water use to the plot level (stand transpiration), basal area was measured for all trees within a 5 m radius around each soil moisture probe. The sensitivity of tree transpiration to reduced precipitation varied by tree, with some increasing and some decreasing in water use during the dry period. Tree-level water use scaled with sapwood area, from 11 to 190 L per day. Stand level water use, based on multiple plots encompassing sap flow and adjacent trees, varied from ∼1.7 to 3.3 mm per day, increasing linearly with plot basal area. Soil water extraction was dependent on root biomass, which was dense at the surface (i.e., 45% in the upper 5 cm) and declined dramatically with depth. As the dry season progressed and the upper soil dried, soil water extraction shifted to deeper levels and model projections suggest that much of the water used during the month-long dry-down could be extracted from the upper 2-3 m. Results indicate variation in rates of soil water extraction across the research area and, temporally, through the soil profile. These results provide key information on whole-tree contributions to transpiration by canopy trees as water availability changes. In addition, information on simultaneous stand level dynamics of soil water extraction that can inform mechanistic models that project tropical forest response to drought.

19.
Virol J ; 8(1): 442, 2011 Sep 20.
Artículo en Inglés | MEDLINE | ID: mdl-21933386

RESUMEN

ABSTRACT: A large quantitative study was carried out to compare the proteome of respiratory syncytial virus (RSV) infected versus uninfected cells in order to determine novel pathways regulated during viral infection. RSV infected and mock-infected HEp2 cells were lysed and proteins separated by preparative isoelectric focussing using offgel fractionation. Following tryptic digestion, purified peptides were characterized using label-free quantitative expression profiling by nano-ultra performance liquid chromatography coupled to electrospray ionisation mass spectrometry with collision energy ramping for all-ion fragmentation (UPLC-MSE). A total of 1352 unique cellular proteins were identified and their abundance compared between infected and non-infected cells. Ingenuity pathway analysis revealed regulation of several central cellular metabolic and signalling pathways during infection. Selected proteins that were found regulated in RSV infected cells were screened by quantitative real-time PCR for their regulation on the transcriptional level. Synthesis of interferon-induced protein with tetratricopeptide repeats 3 (IFIT3) and 5'-3'-exoribonuclease 2 (XRN2) mRNAs were found to be highly induced upon RSV infection in a time dependent manner. Accordingly, IFIT3 protein levels accumulated during the time course of infection. In contrast, little variation was observed in XRN2 protein levels, but different forms were present in infected versus non-infected cells. This suggests a role of these proteins in viral infection, and analysis of their function will shed further light on mechanisms of RNA virus replication and the host cell defence machinery.

20.
J Athl Train ; 56(9): 980-992, 2021 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-34530435

RESUMEN

CONTEXT: As part of clinical practice, athletic trainers (ATs) provide immediate management of patients with acute joint dislocations. Management techniques may include on-site closed joint reduction of the dislocated joint. Although joint reduction is part of the 2020 educational standards, currently practicing ATs may have various levels of exposure, knowledge, and skills. OBJECTIVE: To capture AT self-reported knowledge and practice patterns concerning closed joint reductions. DESIGN: Cohort study. SETTING: Online survey (Qualtrics). PATIENTS OR OTHER PARTICIPANTS: The survey link was emailed to 5000 certified ATs. A total of 772 responses were completed by certified ATs with clinical practice experience (15.4% response rate). MAIN OUTCOME MEASURE(S): Participants were asked to complete a survey about their practice patterns concerning patients with closed joint reductions, which included questions about the types of closed reductions ATs performed most commonly, the frequency of on-site reduction by ATs, and participants' demographic information. Additionally, the survey addressed the ATs' training and comfort level in performing closed reductions and knowledge of standing orders and the state practice act. RESULTS: Ninety percent (n = 694) of ATs reported ever performing a closed reduction (either with or without a physician present), with 10% (n = 78) stating they had never performed a joint reduction. The interphalangeal joint of the finger (73.2% of ATs), shoulder (63.3%), and patella (48.2%) were cited as the 3 most common reductions performed without a physician present. Only 46.5% (n = 359) of ATs indicated receiving training in joint-reduction techniques as part of their precertification athletic training curriculum or program; a greater percentage (64%) said they learned directly from a physician. Fewer than 60% of ATs reported having standing orders related to joint reductions. CONCLUSIONS: Considering the high percentage of ATs who reported performing closed joint reductions and the low percentage with formal training, further development of joint-reduction training and standing orders is warranted.


Asunto(s)
Traumatismos en Atletas , Conmoción Encefálica , Luxaciones Articulares , Deportes , Traumatismos en Atletas/terapia , Estudios de Cohortes , Estudios Transversales , Conocimientos, Actitudes y Práctica en Salud , Humanos , Encuestas y Cuestionarios
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