RESUMEN
In the research devoted to ballet, ground reaction force (GRF) and shoe condition have been identified as possible risk factors for injury. Shoe conditions vary immensely between dancers and could indeed have significant impact on biomechanics and injury rates. Therefore, the objectives of this study were: 1. to investigate the maximal ground reaction force (GRFmax) when ballet dancers land from two jump conditions in pointe shoes, in flat technique shoes, and barefoot; and 2. to explore the effects that specific pointe shoe characteristics (shoe age, shank style) have on GRFmax. Twenty-one healthy female ballet majors in an elite college program volunteered for the study. All participants had similar years of classical ballet training (12.85 ± 2.37). For the study, they performed two ballet jumps, assemblé and grand jeté. Each jump was performed in the three shoe conditions mentioned previously. A total of 18 trials per subject were completed, with the order of jump type and shoe condition randomized. Each jump was landed on a force plate, and maximal GRFs were recorded. A repeated measures analysis of variance was calculated with two within subject factors, shoe type at three levels and jump type at two levels. Tukey's post hoc test was applied to significant findings. Alpha level was set a priori at p = 0.05. Results demonstrated no significant differences in GRFmax between the three shoe conditions; however, significant differences in GRFmax between the jump types were identified. Post-hoc testing revealed that when dancers performed the grand jeté jump, higher GRFmax was obtained compared to the assemblé jump. In conclusion, results of this study indicate that GRFmax varies between ballet jumps; however, it does not appear that shoe condition significantly affects GRFmax.
Asunto(s)
Articulación del Tobillo/fisiología , Baile/fisiología , Extremidad Inferior/fisiología , Equilibrio Postural/fisiología , Rango del Movimiento Articular/fisiología , Fenómenos Biomecánicos , Baile/lesiones , Femenino , Humanos , Presión , Zapatos , Estrés Mecánico , Adulto JovenRESUMEN
Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a hematopoietic growth factor that can stimulate a variety of cells, but its overexpression leads to excessive production and activation of granulocytes and macrophages with many pathogenic effects. This cytokine is a therapeutic target in inflammatory diseases, and several anti-GM-CSF antibodies have advanced to Phase 2 clinical trials in patients with such diseases, e.g., rheumatoid arthritis. GM-CSF is also an essential factor in preventing pulmonary alveolar proteinosis (PAP), a disease associated with GM-CSF malfunction arising most typically through the presence of GM-CSF neutralizing auto-antibodies. Understanding the mechanism of action for neutralizing antibodies that target GM-CSF is important for improving their specificity and affinity as therapeutics and, conversely, in devising strategies to reduce the effects of GM-CSF auto-antibodies in PAP. We have solved the crystal structures of human GM-CSF bound to antigen-binding fragments of two neutralizing antibodies, the human auto-antibody F1 and the mouse monoclonal antibody 4D4. Coordinates and structure factors of the crystal structures of the GM-CSF:F1 Fab and the GM-CSF:4D4 Fab complexes have been deposited in the RCSB Protein Data Bank under the accession numbers 6BFQ and 6BFS, respectively. The structures show that these antibodies bind to mutually exclusive epitopes on GM-CSF; however, both prevent the cytokine from interacting with its alpha receptor subunit and hence prevent receptor activation. Importantly, identification of the F1 epitope together with functional analyses highlighted modifications to GM-CSF that would abolish auto-antibody recognition whilst retaining GM-CSF function. These results provide a framework for developing novel GM-CSF molecules for PAP treatment and for optimizing current anti-GM-CSF antibodies for use in treating inflammatory disorders.
Asunto(s)
Anticuerpos Neutralizantes/química , Complejo Antígeno-Anticuerpo/química , Artritis Reumatoide/terapia , Autoanticuerpos/química , Epítopos/química , Factor Estimulante de Colonias de Granulocitos y Macrófagos/metabolismo , Inmunoterapia/métodos , Anticuerpos Neutralizantes/metabolismo , Artritis Reumatoide/inmunología , Autoanticuerpos/metabolismo , Autoanticuerpos/farmacología , Cristalografía por Rayos X , Citocinas/metabolismo , Epítopos/metabolismo , Factor Estimulante de Colonias de Granulocitos y Macrófagos/genética , Factor Estimulante de Colonias de Granulocitos y Macrófagos/inmunología , Humanos , Estructura Molecular , Unión Proteica , Conformación ProteicaRESUMEN
Recombinant monoclonal antibodies (Ab's) have widespread application as research tools, diagnostic reagents and as biotherapeutics. Whilst studying the cellular molecular switch protein m-ras, a recombinant monoclonal antibody to m-ras was generated for use as a research tool. Antibody genes from a single rabbit B cell secreting IgG to an m-ras specific peptide sequence were expressed in mammalian cells, and monoclonal rabbit IgG binding was characterized by ELISA and peptide array blotting. Although the monoclonal Ab was selected for specificity to m-ras peptide, it also bound to both recombinant full-length m-ras and h-ras proteins. The cross-reactive binding of the monoclonal Ab to h-ras was defined by peptide array blot revealing that the Ab showed preference for peptide sequences containing multiple positively charged amino acid residues. These data reinforce the concept of antibody multispecificity through multiple interactions of the Ab paratope with diverse polypeptides. They also emphasize the importance of immunogen and Ab selection processes when generating recombinant monoclonal Ab's.
Asunto(s)
Anticuerpos Monoclonales/metabolismo , Péptidos/metabolismo , Proteínas Recombinantes/metabolismo , Animales , Especificidad de Anticuerpos , Proteínas Proto-Oncogénicas p21(ras)/metabolismo , ConejosRESUMEN
The human Ab response to certain pathogens is oligoclonal, with preferred IgV genes being used more frequently than others. A pair of such preferred genes, IGVK3-11 and IGVH3-30, contributes to the generation of protective Abs directed against the 23F serotype of the pneumonococcal capsular polysaccharide of Streptococcus pneumoniae and against the AD-2S1 peptide of the gB membrane protein of human CMV. Structural analyses of Fab fragments of mAbs 023.102 and pn132p2C05 in complex with portions of the 23F polysaccharide revealed five germline-encoded residues in contact with the key component, l-rhamnose. In the case of the AD-2S1 peptide, the KE5 Fab fragment complex identified nine germline-encoded contact residues. Two of these germline-encoded residues, Arg91L and Trp94L, contact both the l-rhamnose and the AD-2S1 peptide. Comparison of the respective paratopes that bind to carbohydrate and protein reveals that stochastic diversity in both CDR3 loops alone almost exclusively accounts for their divergent specificity. Combined evolutionary pressure by human CMV and the 23F serotype of S. pneumoniae acted on the IGVK3-11 and IGVH3-30 genes as demonstrated by the multiple germline-encoded amino acids that contact both l-rhamnose and AD-2S1 peptide.
Asunto(s)
Antígenos/inmunología , Fragmentos Fab de Inmunoglobulinas/química , Fragmentos Fab de Inmunoglobulinas/genética , Región Variable de Inmunoglobulina/genética , Región Variable de Inmunoglobulina/inmunología , Antígenos/química , Citomegalovirus/inmunología , Variación Genética , Humanos , Fragmentos Fab de Inmunoglobulinas/inmunología , Región Variable de Inmunoglobulina/química , Conformación Proteica , Streptococcus pneumoniae/inmunologíaRESUMEN
Here we show that male, but not female mice lacking expression of the GTPase M-Ras developed urinary retention with distention of the bladder that exacerbated with age but occurred in the absence of obvious anatomical outlet obstruction. There were changes in detrusor morphology in Mras-/- males: Smooth muscle tissue, which exhibited a compact organization in WT mice, appeared disorganized and became increasingly 'layered' with age in Mras-/- males, but was not fibrotic. Bladder tissue near the apex of bladders of Mras-/- males exhibited hypercontractility in response to the cholinergic agonist carbachol in in vitro, while responses in Mras-/- females were normal. In addition, spontaneous phasic contractions of detrusors from Mras-/- males were increased, and Mras-/- males exhibited urinary incontinence. We found that expression of the muscarinic M2 and M3 receptors that mediate the cholinergic contractile stimuli of the detrusor muscle was dysregulated in both Mras-/- males and females, although only males exhibited a urinary phenotype. Elevated expression of M2R in young males lacking M-Ras and failure to upregulate M3R with age resulted in significantly lower ratios of M3R/M2R expression that correlated with the bladder abnormalities. Our data suggests that M-Ras and M3R are functionally linked and that M-Ras is an important regulator of male bladder control in mice. Our observations also support the notion that bladder control is sexually dimorphic and is regulated through mechanisms that are largely independent of acetylcholine signaling in female mice.
Asunto(s)
Proteínas de Unión al GTP Monoméricas/deficiencia , Receptor Muscarínico M2/fisiología , Receptor Muscarínico M3/fisiología , Caracteres Sexuales , Vejiga Urinaria/metabolismo , Incontinencia Urinaria/fisiopatología , Retención Urinaria/fisiopatología , Acetilcolina/fisiología , Envejecimiento/genética , Envejecimiento/fisiología , Animales , Femenino , Regulación de la Expresión Génica , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Proteínas de Unión al GTP Monoméricas/genética , Proteínas de Unión al GTP Monoméricas/fisiología , Contracción Muscular , Músculo Liso/metabolismo , Fenotipo , Proteinuria/genética , Proteinuria/fisiopatología , ARN Mensajero/biosíntesis , Receptor Muscarínico M2/biosíntesis , Receptor Muscarínico M2/genética , Receptor Muscarínico M3/biosíntesis , Receptor Muscarínico M3/genética , Vejiga Urinaria/patología , Vejiga Urinaria Hiperactiva/genética , Vejiga Urinaria Hiperactiva/fisiopatología , Incontinencia Urinaria/genética , Retención Urinaria/genética , Micción/fisiología , Proteínas rasRESUMEN
BACKGROUND: The molecular mechanisms that determine social behavior are poorly understood. Pheromones play a critical role in social recognition in most animals, including mice, but how these are converted into behavioral responses is largely unknown. Here, we report that the absence of the small GTPase M-Ras affects social behavior in mice. RESULTS: In their interactions with other males, Mras(-/-) males exhibited high levels of territorial aggression and social investigations, and increased fear-related behavior. They also showed increased mating behavior with females. Curiously, increased aggression and mating behaviors were only observed when Mras(-/-) males were paired with Mras(-/-) partners, but were significantly reduced when paired with wild-type (WT) mice. Since mice use pheromonal cues to identify other individuals, we explored the possibility that pheromone detection may be altered in Mras(-/-) mice. Unlike WT mice, Mras(-/-) did not show a preference for exploring unfamiliar urinary pheromones or unfamiliar isogenic mice. Although this could indicate that vomeronasal function and/or olfactory learning may be compromised in Mras(-/-) mice, these observations were not fully consistent with the differential behavioral responses to WT and Mras(-/-) interaction partners by Mras(-/-) males. In addition, induction of c-fos upon pheromone exposure or in response to mating was similar in WT and Mras (-/-) mice, as was the ex vivo expansion of neural progenitors with EGF. This indicated that acute pheromone detection and processing was likely intact. However, urinary metabolite profiles differed between Mras(-/-) and WT males. CONCLUSIONS: The changes in behaviors displayed by Mras(-/-) mice are likely due to a complex combination of factors that may include an inherent predisposition to increased aggression and sexual behavior, and the production of distinct pheromones that could override the preference for unfamiliar social odors. Olfactory and/or social learning processes may thus be compromised in Mras(-/-) mice.
Asunto(s)
Conducta Animal/fisiología , Proteínas de Unión al GTP Monoméricas/fisiología , Feromonas/fisiología , Conducta Social , Agresión/fisiología , Animales , Femenino , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Receptores de Feromonas , Conducta Sexual Animal/fisiología , Órgano Vomeronasal/fisiología , Proteínas rasRESUMEN
OBJECTIVE: The purpose of this study was to determine the prevalence of chronic ankle instability among high school and collegiate athletes. DESIGN: Descriptive epidemiological survey. METHODS: Athletes from four high schools and a division I university were contacted to participate. For collegiate athletes, a questionnaire packet was distributed during preparticipation physicals. For high school athletes, parental consent was obtained and then questionnaires were distributed during preparticipation physicals, parent meetings, or individual team meetings. All athletes completed the Cumberland Ankle Instability Tool for both their left and right ankles. Subjects also provided general demographic data and completed the Ankle Instability Instrument regarding history of lateral ankle sprains and giving way. Athletes were identified as having chronic ankle instability if they scored less than 24 on the Cumberland Ankle Instability Tool. RESULTS: Of the 512 athletes who completed and returned surveys, 23.4% were identified as having chronic ankle instability. High school athletes were more likely to have chronic ankle instability than their collegiate counterparts (P < .001). Chronic ankle instability was more prevalent among women than among men in both high school (P = .01) and collegiate settings (P = .01). CONCLUSIONS: Findings of this study revealed differences in the distribution of chronic ankle instability that warrant further study.
Asunto(s)
Articulación del Tobillo/fisiopatología , Atletas/estadística & datos numéricos , Inestabilidad de la Articulación/epidemiología , Estudiantes/estadística & datos numéricos , Adolescente , Traumatismos del Tobillo/epidemiología , Enfermedad Crónica , Femenino , Humanos , Puntaje de Gravedad del Traumatismo , Inestabilidad de la Articulación/fisiopatología , Masculino , Prevalencia , Distribución por Sexo , Esguinces y Distensiones/epidemiología , Encuestas y Cuestionarios , Estados Unidos/epidemiología , Adulto JovenRESUMEN
The origin of pathogenic autoantibodies remains unknown. Idiopathic pulmonary alveolar proteinosis is caused by autoantibodies against granulocyte-macrophage colony-stimulating factor (GM-CSF). We generated 19 monoclonal autoantibodies against GM-CSF from six patients with idiopathic pulmonary alveolar proteinosis. The autoantibodies used multiple V genes, excluding preferred V-gene use as an etiology, and targeted at least four nonoverlapping epitopes on GM-CSF, suggesting that GM-CSF is driving the autoantibodies and not a B-cell epitope on a pathogen cross-reacting with GM-CSF. The number of somatic mutations in the autoantibodies suggests that the memory B cells have been helped by T cells and re-entered germinal centers. All autoantibodies neutralized GM-CSF bioactivity, with general correlations to affinity and off-rate. The binding of certain autoantibodies was changed by point mutations in GM-CSF that reduced binding to the GM-CSF receptor. Those monoclonal autoantibodies that potently neutralize GM-CSF may be useful in treating inflammatory disease, such as rheumatoid arthritis and multiple sclerosis, cancer, and pain.
Asunto(s)
Anticuerpos Monoclonales/inmunología , Autoanticuerpos/inmunología , Factor Estimulante de Colonias de Granulocitos y Macrófagos/inmunología , Factor Estimulante de Colonias de Granulocitos y Macrófagos/metabolismo , Proteinosis Alveolar Pulmonar/inmunología , Linfocitos B/citología , Antígeno CD11b/metabolismo , Línea Celular Tumoral , Proliferación Celular , Mapeo Epitopo/métodos , Humanos , Memoria Inmunológica , Concentración 50 Inhibidora , Cinética , Mutación , Neutrófilos/metabolismo , Mutación Puntual , Proteinosis Alveolar Pulmonar/metabolismo , Resonancia por Plasmón de Superficie , Linfocitos T/citologíaRESUMEN
Human granulocyte macrophage colony-stimulating factor (hGM-CSF) is a haematopoietic growth factor and proinflammatory cytokine. Recombinant hGM-CSF is important not only as a research tool but also as a biotherapeutic. However, rhGM-CSF expressed in E. coli is known to form inclusion bodies of misfolded, aggregated protein. Refolding and subsequent purification of rhGM-CSF from inclusion bodies is difficult with low yields of bioactive protein being produced. Here we describe a method for the isolation, refolding and purification of bioactive rhGM-CSF from inclusion bodies. The method is straightforward, not requiring extensive experience in protein refolding nor purification and using standard laboratory equipment.
Asunto(s)
Factor Estimulante de Colonias de Granulocitos y Macrófagos/química , Factor Estimulante de Colonias de Granulocitos y Macrófagos/aislamiento & purificación , Ingeniería de Proteínas/métodos , Pliegue de Proteína , Proteínas Recombinantes/química , Proteínas Recombinantes/aislamiento & purificación , Clonación Molecular , Cartilla de ADN/genética , Escherichia coli , Humanos , Cuerpos de Inclusión/química , Espectrometría de MasasRESUMEN
CONTEXT: Although strength training is commonly used to rehabilitate ankle injuries, studies investigating the effects of strength training on proprioception have shown conflicting results. OBJECTIVE: To determine the effects of a 6-week strength-training protocol on force sense and strength development in participants with functional ankle instability. DESIGN: Randomized controlled clinical trial. SETTING: University athletic training research laboratory. PATIENTS OR OTHER PARTICIPANTS: A total of 40 participants with functional ankle instability were recruited. They were randomly placed into a training group (10 men, 10 women: age = 20.9 ± 2.2 years, height = 76.4 ± 16.1 cm, mass = 173.0 ± 7.9 kg) or control group (10 men, 10 women: age = 20.2 ± 2.1 years, height = 78.8 ± 24.5 cm, mass = 173.7 ± 8.2 kg). INTERVENTION(S): Participants in the training group performed strength exercises with the injured ankle 3 times per week for 6 weeks. The protocol consisted of a combination of rubber exercise bands and the Multiaxial Ankle Exerciser, both clinically accepted strengthening methods for ankle rehabilitation. The progression of this protocol provided increasingly resistive exercise as participants changed either the number of sets or resistance of the Thera-Band or Multiaxial Ankle Exerciser. Main Outcome Measure(s): A load cell was used to measure strength and force sense. Inversion and eversion strength was recorded to the nearest 0.01 N. Force-sense reproduction was measured at 2 loads: 20% and 30% of maximal voluntary isometric contraction. RESULTS: Increases in inversion (F(1,38) = 11.59, P < 0.01, η(p)(2) = 0.23, power = 0.91) and eversion (F(1,38) = 57.68, P < .01, η(p)(2) = 0.60, power = 0.99) strength were found in the training group at the posttest when compared with the control group. No significant improvements were noted in force-sense reproduction for either group. CONCLUSIONS: Strength training at the ankle increased strength but did not improve force sense.
Asunto(s)
Traumatismos del Tobillo/rehabilitación , Traumatismos del Tobillo/terapia , Terapia por Ejercicio , Inestabilidad de la Articulación/rehabilitación , Entrenamiento de Fuerza , Tobillo , Traumatismos del Tobillo/fisiopatología , Articulación del Tobillo , Ejercicio Físico , Femenino , Humanos , Inestabilidad de la Articulación/fisiopatología , Masculino , Fuerza Muscular , Propiocepción , Adulto JovenRESUMEN
Fragile X syndrome is caused by the absence of the Fragile X Mental Retardation Protein (FMRP), an RNA-binding protein. FMRP is associated with messenger RiboNucleoParticles (mRNPs) present in polyribosomes and its absence in neurons leads to alteration in synaptic plasticity as a result of translation regulation defects. The molecular mechanisms by which FMRP plays a role in translation regulation remain elusive. Using immunoprecipitation approaches with monoclonal Ab7G1-1 and a new generation of chicken antibodies, we identified Caprin1 as a novel FMRP-cellular partner. In vivo and in vitro evidence show that Caprin1 interacts with FMRP at the level of the translation machinery as well as in trafficking neuronal granules. As an RNA-binding protein, Caprin1 has in common with FMRP at least two RNA targets that have been identified as CaMKIIα and Map1b mRNAs. In view of the new concept that FMRP species bind to RNA regardless of known structural motifs, we propose that protein interactors might modulate FMRP functions.
Asunto(s)
Proteínas de Ciclo Celular/metabolismo , Proteína de la Discapacidad Intelectual del Síndrome del Cromosoma X Frágil/metabolismo , Neuronas/metabolismo , Proteínas de Unión al ARN/metabolismo , Ribonucleoproteínas/química , Secuencias de Aminoácidos , Animales , Anticuerpos Monoclonales/química , Secuencia de Bases , Encéfalo/metabolismo , Proteína Quinasa Tipo 2 Dependiente de Calcio Calmodulina/metabolismo , Cartilla de ADN/genética , Células HeLa , Humanos , Inmunoprecipitación , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Proteínas Asociadas a Microtúbulos/metabolismo , Datos de Secuencia Molecular , Células 3T3 NIH , Polirribosomas/metabolismo , Unión Proteica , Biosíntesis de ProteínasRESUMEN
Reports in the literature suggest an abundance of lower extremity injuries in ballet dancers; however, few studies have identified the underlying causes of these injuries. Excessive ground reaction forces and shoe type are two potential contributing factors. Eighteen collegiate female ballet majors volunteered for this study. Each participant performed 12 trials of a basic ballet jump, six trials in flat shoes and 6 trials in pointe shoes, landing on a force plate. Ground reaction force (Newtons) and jump height (centimeters) were assessed for each trial. The mean ground reaction force and jump height for each shoe condition was used for statistical analysis. Two dependent t-tests were conducted to determine differences between the shoe types, one for ground reaction force and one for jump height. Alpha level was set at p < .05. We found that the ground reaction force was significantly higher when landing in flat shoes than in pointe shoes (p = .003). There was no significant difference in jump height between the two shoe conditions. This leads us to believe that the increase in ground reaction force was produced primarily by the shoe type.
Asunto(s)
Baile/fisiología , Zapatos , Estrés Mecánico , Adulto , Fenómenos Biomecánicos , Baile/lesiones , Femenino , Humanos , Persona de Mediana EdadRESUMEN
The human Ab response to many common pathogens is oligoclonal, with restricted usage of Ig V-genes. Intriguingly, the IGVK3-11 and IGVH3-30 V-genes are repeatedly paired in protective Abs against the 23F polysaccharide of Streptococcus pneumoniae, as well as against the gB envelope protein of human CMV, where germline-encoded amino acids make key contacts with the gB protein. We constructed IgGs encoded by the germline IGVK3-11 and IGVH3-30 V-genes together with DNA encoding the respective CDR3 regions of the L chain and H chain found in a hypermutated anti-23F Ab. These IgGs encoded by germline V-genes bound specifically to 23F pneumococcal capsular polysaccharides with no reactivity to other serotypes of pneumococcal capsular polysaccharides or arrayed glycans and recognized L-rhamnose, a component of the 23F repeating subunit. IgGs encoded by this pair of germline V-genes mediated complement-dependent phagocytosis of encapsulated 23F S. pneumoniae by human neutrophils. Mutations in CDRL3 and CDRH3 had significant effects on binding. Thus, IGKV3-11 and IGHV3-30, depending on with which distinct DNA sequences encoding CDR3 they are recombined, can encode binding sites for protective Abs against chemically distinct Ags and thus, may encode innate immunological memory against human CMV and S. pneumoniae.
Asunto(s)
Regiones Determinantes de Complementariedad/genética , Inmunidad Innata/genética , Región Variable de Inmunoglobulina/genética , Memoria Inmunológica/genética , Virus Sincitiales Respiratorios/inmunología , Hipermutación Somática de Inmunoglobulina/genética , Streptococcus pneumoniae/inmunología , Secuencia de Aminoácidos , Anticuerpos Monoclonales/metabolismo , Sitios de Unión de Anticuerpos/genética , Células Cultivadas , Regiones Determinantes de Complementariedad/metabolismo , Humanos , Cadenas Pesadas de Inmunoglobulina/genética , Cadenas Pesadas de Inmunoglobulina/metabolismo , Cadenas Ligeras de Inmunoglobulina/genética , Cadenas Ligeras de Inmunoglobulina/metabolismo , Región Variable de Inmunoglobulina/química , Región Variable de Inmunoglobulina/metabolismo , Datos de Secuencia Molecular , Neutrófilos/inmunología , Neutrófilos/microbiología , Neutrófilos/virología , Virus Sincitiales Respiratorios/metabolismo , Virus Sincitiales Respiratorios/patogenicidad , Streptococcus pneumoniae/metabolismo , Streptococcus pneumoniae/patogenicidadRESUMEN
CONTEXT: Peroneal reaction to sudden inversion has been determined to be too slow to overcome the joint motion. A focused plyometric training program may decrease the muscle's reaction time. OBJECTIVE: To determine the effect of a 6-wk plyometric training program on peroneus longus reaction time. DESIGN: Repeated measures. SETTING: University research laboratory. PARTICIPANTS: 48 healthy volunteers (age 20.0+/-1.2 y, height 176.1+/-16.9 cm, weight 74.5+/-27.9 kg) from a large Midwestern university. Subjects were randomly assigned to either a training group or a control group. INTERVENTIONS: Independent variables were group at 2 levels (training and no training) and time at 2 levels (pretest and posttest). The dependent variable was peroneal latency measured with surface electromyography. A custom-made trapdoor device capable of inverting the ankle to 30 degrees was also used. Latency data were obtained from the time the trapdoor dropped until the peroneus longus muscle activated. Peroneal latency was measured before and after the 6-wk training period. The no-training group was instructed to maintain current activities. The training group performed a 6-wk plyometric protocol 3 times weekly. Data were examined with a repeated-measures ANOVA with 1 within-subject factor (time at 2 levels) and 1 between-subjects factor (group at 2 levels). A priori alpha level was set at PAsunto(s)
Tobillo/fisiología
, Ejercicio Físico/fisiología
, Músculo Esquelético/fisiología
, Tiempo de Reacción/fisiología
, Adulto
, Electromiografía
, Femenino
, Humanos
, Masculino
RESUMEN
BACKGROUND: The purpose of this investigation was to evaluate the relationship between the severity of functional and mechanical ankle instability in physically active individuals. MATERIALS AND METHODS: Eighty college aged physically active individuals from a large university were recruited for this study. All subjects had unilateral functional ankle instability (FAI). FAI was defined as a history of at least two ankle sprains and a score less than or equal to 27 on the Cumberland Ankle Instability Tool (CAIT). The contralateral limb had no history of ankle injury or instability. Anterior displacement (mm) and talar tilt (degrees) were measured using the LigMaster joint arthrometer to identify mechanical ankle instability(MAI). Individuals were tested bilaterally and the maximum value attained during talar tilt and anterior displacement was used for statistical analysis. RESULTS: First we evaluated side-to-side differences in MAI in all subjects. We found no significant difference between the FAI and the non-FAI ankle for anterior displacement (t(1.79)=1.66, p = 0.10) or talar tilt (t(1.79)=-0.07, p=0.95). Secondly, we evaluated the relationship between the FAI and MAI measures and found no significant correlations between the severity of FAI and magnitude of anterior displacement(r=0.18, p=0.12) or talar tilt (r=0.09, p=0.42). CONCLUSION: This study demonstrated there was no side-to-side difference in MAI in individuals with unilateral functional ankle instability. Similarly, we also conclude there was no significant relationship between the severity of FAI and MAI. We feel that these findings suggest the symptoms of FAI may not be related to ankle joint laxity, but instead due to other factors associated with FAI.
Asunto(s)
Traumatismos del Tobillo/fisiopatología , Articulación del Tobillo/fisiopatología , Inestabilidad de la Articulación/fisiopatología , Esguinces y Distensiones/fisiopatología , Adolescente , Femenino , Humanos , Inestabilidad de la Articulación/diagnóstico , Masculino , Debilidad Muscular , Propiocepción/fisiología , Recurrencia , Índice de Severidad de la Enfermedad , Estrés Mecánico , Adulto JovenRESUMEN
OBJECTIVE: To compare the dichotomous results for 7 ulnar nerve clinical motor tests (Froment's sign, Wartenberg's sign, finger flexion sign, Jeanne's sign, crossed finger test, Egawa's sign, presence of clinical fasciculations) with motor nerve conduction velocity findings. DESIGN: A static group comparison design assessed for differences among dichotomous test outcomes with respect to motor nerve conduction velocity. SETTING: Five medical facilities throughout the United States provided data for this study. PARTICIPANTS: Records from participants (N=26) with diagnosed ulnar neuropathy at the elbow were included for data analysis. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Demographic data included age, sex, handedness, duration of symptoms, and the number of days between the clinical and electrodiagnostic exam. Other dependent variables included motor conduction velocity of the ulnar nerve, compound muscle action potential amplitude, and the dichotomous clinical motor test outcomes. RESULTS: Two motor signs, the presence of clinical fasciculations and a positive finger flexion sign, were identified more frequently (each present in 11 patients) than the other motor signs. An analysis of covariance revealed significant differences in motor nerve conduction velocity between positive and negative results for all the clinical motor tests except for the finger flexion sign. Significant chi-square analyses were found for the following comparisons: the presence of clinical fasciculations and Froment's sign, the finger flexion sign and the crossed finger test, Egawa's sign and Froment's sign, Warteberg's sign and Froment's sign, the crossed finger test and Froment's sign, and Egawa's sign and Wartenberg's sign. CONCLUSIONS: Some clinical motor tests are better than others at identifying early motor involvement, providing the rehabilitation professional some insight regarding the relative decrement of motor nerve conduction velocity when a selected test is positive.
Asunto(s)
Electrofisiología/métodos , Síndromes de Compresión Nerviosa/fisiopatología , Nervio Cubital/fisiopatología , Adulto , Análisis de Varianza , Distribución de Chi-Cuadrado , Femenino , Humanos , Masculino , Persona de Mediana Edad , Conducción Nerviosa/fisiología , Estados UnidosRESUMEN
STUDY DESIGN: Experimental laboratory testing using a cross-sectional design. OBJECTIVES: To determine if functional performance deficits are present in individuals with functional ankle instability (FAI) in 4 single-limb hopping tests, including figure-of-8 hop, side hop, 6-meter crossover hop, and square hop. BACKGROUND: Conflicting results exist regarding the presence of functional deficits in individuals with FAI. It is important to evaluate whether functional performance deficits are present in this population, as well as if subjective feelings of giving way can assist in identifying these deficits. METHODS: Sixty college students volunteered for this study. Thirty participants with unilateral ankle instability were placed in the FAI group and 30 participants with no history of ankle injuries were placed in the control group. The FAI group was subsequently further divided to indicate those that reported giving way during the functional test (FAI-GW) and those that did not (FAI-NGW). Time to complete each test was recorded and the mean of 3 trials for each test were used for statistical analysis. To identify performance differences, we used 4 mixed-design 2-way (side-by-group) ANOVAs, 1 for each hop test. A Tukey post hoc test was completed on all significant findings. RESULTS: We identified a significant side-by-group interaction for all 4 functional performance tests (P<.05). Specifically, for each functional performance test, the FAI limb performed significantly worse than the contralateral uninjured limb in the FAI-GW group. Additionally, the FAI limb in the FAI-GW group performed worse than the FAI limb in the FAI-NGW group, and the matched limb in the control group in 3 of the 4 functional performance tests. CONCLUSION: We found that functional performance deficits were present in participants with FAI who also experienced instability during the test. This difference was identified when comparing the FAI limb to the contralateral uninjured limb as well as control participants. However, the performance deficits identified in this study were relatively small. Future research in this area is needed to further evaluate the clinical meaningfulness of these findings. Finally, we found that limb dominance did not affect performance.
Asunto(s)
Prueba de Esfuerzo/métodos , Inestabilidad de la Articulación/fisiopatología , Pierna/fisiopatología , Movimiento/fisiología , Rango del Movimiento Articular/fisiología , Estudios Transversales , Femenino , Humanos , Inestabilidad de la Articulación/diagnóstico , Masculino , Análisis y Desempeño de Tareas , Adulto JovenRESUMEN
The lens of the eye is derived from the non-neural ectoderm situated next to the optic vesicle. Fibroblast growth factor (FGF) signals play a major role at various stages of vertebrate lens development ranging from induction and proliferation to differentiation. Less is however known about the identity of genes that are induced by FGF activity within the lens. We have isolated and characterized mouse cytoplasmic activation/proliferation-associated protein-2 (Caprin2), with domains belonging to both the Caprin family and the C1q and tumour necrosis factor (TNF) super-family. Here we show that Caprin2 is expressed in the developing vertebrate lens in mouse and chick, and that Caprin2 expression is up-regulated in primary lens fiber cells, after the induction of crystallins the earliest known markers for differentiated lens fiber cells. Caprin2 is subsequently down-regulated in the centre of the lens at the time and at the position of the first fiber cell denucleation and terminal differentiation. In vitro analyses of lens fiber cell differentiation provide evidence that FGF activity emanating from neighboring prospective retinal cells is required and that FGF8 activity is sufficient to induce Caprin2 in lens fiber cells. These results not only provide evidence that FGF signals induce the newly characterized protein Caprin2 in the lens, but also support the general idea that FGF signals are required for lens fiber cell differentiation.