The Spin Structure of the Nucleon

We present an overview of recent experimental and theoretical advances in our understanding of the spin structure of protons and neutrons.Comment: 84 pages, 29 figure

DNA DAMAGE INDUCED BY EXERCISE IN MIDDLE GLUTEAL MUSCLE OF THOROUGHBREDS HORSES

ABSTRACT It is well known that two classical consequences of severe exercise are soreness and stiffness. Both consequences develop in the days following severe exercise. The objective of the present work was to establish the association between DNA damage, the energetic metabolism and the effects of the generation of oxygen free radicals in middle gluteal muscle of horses, measured after a severe exercise bout on a treadmill. Four thoroughbreds, ranging in aged from 3 to 4 years old were used for this study. The test consisted in warming-up, severe exercise, and cooling down. Venous blood samples were withdrawn via a catheter from the jugular vein before and at 5 min, 30 min, 45 min and 24 h post-exercise. Muscle biopsy samples were obtained from the middle gluteal muscle before and at 45 min and 24 h after exercise. All statistical analyses were performed using Student's t-tests for unpaired data. ATP concentration significantly decreased (p< .05) after 45 min of severe exercise and subsequently increased by 24 h. Plasma CK activity increased significantly (p< .05) after 45 min and 24 h of exercise. Both free MDA and protein-bound MDA concentrations significantly increased (p< .001) after 45 min of exercise, and both of them returned almost to the pre-exercise values after 24 h of exercise. The percentage of TUNEL positive cells increased significantly (p< .001) so as the plasma hypoxanthine and uric acid level during exercise. It was strongly suggested that the generation of free radicals was developed during exercise. The mechanism of exercise-induced myopathy could be the cell membrane damage by lipid peroxidation and DNA fragmentation in the working muscle cells by free radicals generation. RESUMEN Dos consecuencias clásicas del ejercicio severo son el dolor y la rigidez. Ambas consecuencias ocurren en los días siguientes al ejercicio. El objetivo de este trabajo fue establecer la asociación entre daño en el ADN, el metabolismo energético y la generación de radicales del oxígeno en el músculo gluteo medio de caballos sometidos a ejercicio severo. Se utilizaron 4 caballos de entre 3 y 4 años de edad, que fueron sometidos a ejercicio en cinta ergométrica. Se obtuvieron muestras de sangre por punción yugular antes, a los 5, 30, 45 minutos y 24 horas pos ejercicio. Se realizaron biopsias del músculo gluteo medio antes, a los 45 minutos y 24 horas pos ejercicio. Se realizaron múltiples determinaciones y mediciones y en todos los casos el análisis estadístico se realizó utilizando el test de t para muestras no apareadas. La concentración de ATP disminuyó significativamente a los 45 minutos de ejercicio severo (p< 0, 05) y se recupero a las 24 hs. La actividad plasmática CK se incremento significativamente (p< .05) a los 45 minutos y 24 h de realizado el ejercicio. Tanto el MDA libre como el fijado a proteínas aumentaron sus concentraciones significativamente (p< .001) a 45 minutos, y ambos volvieron a los valores de pre ejercicio a las 24 horas. El porcentaje de células tunnel positive y los niveles plasmáticos de hipoxantina y ácido úrico se incrementaron signioficativamente durante el ejercicio (p< .001). Los datos obtenidos sugieren la generación de radicales libres durante el ejercicio y la producción de daño en el ADN. El mecanismo por el cual el ejercicio induce miopátias puede deberse al daño de membranas celulares por peroxidación de lípidos y a la fregmentación del ADN, debida a la producción de radicales libres

Congenital muscular dystrophies with cognitive impairment. A population study

Cognitive impairment has been reported in a significant proportion of patients with congenital muscular dystrophies (CMD), generally associated with brain changes

Congenital muscular dystrophies with defective glycosylation of dystroglycan: a population study

Congenital muscular dystrophies (CMD) with reduced glycosylation of alpha-dystroglycan (alpha-DG) are a heterogeneous group of conditions associated with mutations in six genes encoding proven or putative glycosyltransferases