RESUMEN
OBJECTIVE: Surface and intramuscular electromyography was used to investigate shoulder muscle activity in subjects with multidirectional instability (MDI). METHODS: Subjects (seven MDI, 11 control) performed repetitive shoulder abduction/adduction, flexion/extension and internal/external rotation movements on an isokinetic dynamometer. The activity of the deltoid, infraspinatus, supraspinatus, latissimus dorsi, and pectoralis major muscles were recorded using double-differential surface and intramuscular fine-wire electrodes. A repeated measures analysis of variance evaluated group differences in the amplitude, onset, termination and duration of the muscle activity. RESULTS: Significant activation parameter differences for the supraspinatus, infraspinatus, posterior deltoid and pectoralis major muscles were found in the subjects with MDI. The rotator cuff and posterior deltoid muscles demonstrated abbreviated periods of activity when performing internal/external rotation, despite activation amplitudes that were similar to the controls. In contrast, the activation of the pectoralis major differed from the control group in both the amplitude and time domains when performing shoulder extension. CONCLUSIONS: MDI is associated with atypical patterns of muscle activity that occur even when highly constrained movements are used to elicit the activity. SIGNIFICANCE: In addition to glenohumeral hyperlaxity, the results suggest that dysfunctional neuromuscular control of the rotator cuff is also a contributing factor to the pathoetiology of MDI.
Asunto(s)
Inestabilidad de la Articulación/patología , Músculo Esquelético/fisiología , Hombro/fisiología , Adulto , Estudios de Casos y Controles , Electromiografía , Humanos , Masculino , MovimientoRESUMEN
We studied the effect of a single oral dose of ICI 204,219 on subject response to bronchoprovocation and quantitative skin testing with standardized allergen (cat dander). Cat-allergic male subjects with asthma entered the double-blind, randomized, placebo-controlled, crossover study. Each subject received a 40 mg dose of ICI 204,219 or placebo on study days separated by at least 10 days. After dosing, each subject underwent bronchoprovocation with cat allergen until a provocative dose of allergen caused a 20% decrease in FEV1 or a maximum dose of 30,000 AU/ml was reached. Fifteen subjects entered and 13 completed the study. No significant shift in the dose-response curve of the quantitative skin test occurred in any subject. A mean tenfold increase in the interpolated provocative concentration causing a 20% decrease in FEV1 was observed between ICI 204,219 (6996 +/- 3204 AU/ml) and placebo (460 +/- 98 AU/ml). Eight of 12 subjects required more antigen to provoke a bronchoprovocation response after dosing with ICI 204,219 than that required with placebo (range, threefold to 30-fold), three demonstrated no difference (less than twofold), and one subject required less antigen after ICI 204,219 (sevenfold less). Area under the curve measurements were significantly different (p less than 0.05) between ICI 204,219 and placebo for the fixed time from the end point of the allergen bronchoprovocation to 5 hours after provocation. In conclusion, this trial demonstrates that a single oral dose of ICI 204,219 antagonizes the bronchoconstriction induced by inhaled cat allergen.