RESUMEN

In this preliminary study we measured maximum walking distance and walking time on four consecutive days in 29 patients with clinically stable multiple sclerosis (MS). Patients were included in the study if they could achieve a maximum unaided walking distance of 100 up to 500 m. Our results showed a certain day-to-day variability of maximum walking distance, in some cases meaning changes up to 1.5 points in the expanded disability status scale (EDSS), which could be misinterpreted as a progression of the disease. Simultaneous measurements of maximum walking time showed a similar variability, unlike the mean walking speed which turned out to be more stable. Our results therefore suggest that scoring of MS patients should not be based on one single measurement of the maximum walking distance. The more reliable parameter appears to be the mean walking speed.

Asunto(s)

Esclerosis Múltiple/fisiopatología , Índice de Severidad de la Enfermedad , Caminata , Adulto , Anciano , Evaluación de la Discapacidad , Femenino , Humanos , Masculino , Persona de Mediana Edad

RESUMEN

Activities catalyzing the synthesis of fructose-2,6-bisphosphate (fructose-6-phosphate,2-kinase or Fru-6-P,2K) and its breakdown (fructose-2,6-bisphosphatase or Fru-2,6-P(2)ase) were identified in leaves of corn (Zea mays), a C(4) plant. Fru-6-P,2K and Fru-2,6-P(2)ase were both localized mainly, if not entirely, in the leaf mesophyll cells. A partially purified preparation containing the two activities revealed that the kinase and phosphatase were regulated by metabolite effectors in a manner generally similar to their counterparts in C(3) species. Thus, corn Fru-6-P,2K was activated by inorganic phosphate (Pi) and fructose-6-phosphate, and was inhibited by 3-phosphoglycerate and dihydroxyacetone phosphate. Fru-2,6-P(2)ase was inhibited by its products, fructose-6-phosphate and Pi. However, unlike its spinach equivalent, corn Fru-2,6-P(2)ase was also inhibited by 3-phosphoglycerate and, less effectively, by dihydroxyacetone phosphate. The C(4) Fru-6-P,2K and Fru-2,6-P(2)ase were also quite sensitive to inhibition by phosphoenolpyruvate, and each enzyme was also selectively inhibited by certain other metabolites.