Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.3.3.1 (citrate synthase)
 4,488 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Persons who suffered poliomyelitis 3 or more decades ago now report functional decline and symptoms designated as "post-polio syndrome". The objects of this investigation were to identify subjects fulfilling the criteria of this syndrome, to describe their motor impairment and resulting disabilities/handicaps, to study the adaptive changes in the muscle structure and effects of a resistance exercise program. Forty-one late-polio subjects, 40-65 years old, volunteered for the studies of motor impairment, subgroups of those volunteered to further studies of long-term and short-term adaptations. Seventy-five per cent of the subjects met the criteria for the post-polio syndrome. Complete manual muscle tests and dynamometer measurements of knee muscle strength revealed severe motor impairment predominantly in the lower extremities, the strength of the latter correlating to the degree of mobility handicap. In biopsies from the vastus lateralis muscle, type grouping was frequent. Half of the subjects demonstrated over 70% occurrence of type I fibers with negative significant correlation to strength in the female subjects. Cross-section areas of muscle fibers were on average twice the normal, with negative significant correlation to strength values in male subjects. Muscle enzymatic activity values showed large individual variations; oxidative activities (citrate synthase) were low or very low, while average glycolytic activities were nearly normal. Macro EMG and single-fiber EMG measurements in the vastus lateralis muscle demonstrated large macro motor unit potentials and increased fiber density. Neuromuscular transmission was disturbed as identified by jitter and blockings in most subjects regardless of the occurrence of new muscular symptoms. A statistically significant increase in strength (25-30%) resulted from a 6 weeks' heavy resistance exercise program, utilizing a dynamometer, without any obvious side-effects. Strength improvement was maintained for 6-12 months after training while fatigue index increased. A substantial impact on intermediate (secondary or instrumental) ADL, most severely affecting the quality of mobility, was generally found, while little effect was found on primary ADL as revealed by the Katz' ADL index, the Functional Status Questionnaire and the WHO ICIDH Classification of Handicap. The impaired motor function confirms findings in earlier studies. It also corresponds with the locomotor disabilities and handicaps. The negative correlation of strength to cross-section fiber area might result from excessive use of remaining fibers leading to a prominent hypertrophy in the weakest subjects. Enzyme activities probably reflect the pattern of everyday activities with little demands on endurance.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Muscle adaptation and disability in late poliomyelitis. 183 29

Capillary supply and oxidative and glycolytic enzyme activities were determined in muscle biopsies from the tibialis anterior muscle in six prior polio patients and a control group. The polio patients, who had paresis and atrophy, but were able to walk normally by making maximal use of all remaining anterior tibial motor units, showed type I (slow-twitch) muscle fibre predominance with a mean (SD) of 98 (2%) type I fibres versus 81 (8)% in the controls (p less than 0.01) and muscle fibre hypertrophy, the average type I fibre cross-sectional area being 108% (p less than 0.005) larger than in the controls. The number of capillaries per muscle fibre was not significantly different from that in the control group, but with the increased muscle fibre area in the polio patients, the capillary density was significantly lower. The number of capillaries in contact with type I fibres relative to fibre area was 40% lower in the patients than in the controls (p less than 0.005). The levels of citrate synthase and phosphofructokinase were significantly lower (38% and 33%, respectively, p less than 0.05) in the patients than in the controls, indicating decreased oxidative and glycolytic potentials in the muscle fibres of the polio patients. It is proposed that the abnormal high-frequency activation of all remaining motor units during each step cycle recorded in these patients constitutes a stimulus for type I muscle fibre predominance and hypertrophy but that the overall low muscle usage results in a decreased stimulation of capillary proliferation and mitochondrial enzyme synthesis. The low capillary density and decreased oxidative and glycolytic enzyme potentials might be important factors for the development of muscle weakness, fatigue and muscle pain, which are commonly occurring symptoms in patients with prior poliomyelitis.
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PMID:Prior poliomyelitis-reduced capillary supply and metabolic enzyme content in hypertrophic slow-twitch (type I) muscle fibres. 203 Mar 51

Nineteen post-polio subjects (9 men and 10 women) aged 41-65 years were studied by means of muscle strength measurements (Cybex) of knee extension and muscle biopsies of the vastus lateralis for morphometric, histopathological and enzymatic analyses. Data from a reference group of 10 male subjects, age 42-51 years, are also given. Fourteen of the post-polio subjects had experienced a post-polio syndrome-like drop in function. All had had polio at least 25 years earlier. In nine of the 19 subjects, type I fibers accounted for more than 70% of the total. There was a significant negative correlation between muscle strength and the percentage of type I fibers in women. Large cross-section areas of muscle fibers were found, with an average mean fiber area of 8 microns 2 X 10(3). It is assumed that the large muscle fiber areas are due to an extreme use of the remaining muscle fibers in post-polio subjects with low muscle strength. There were significant negative correlations between muscle strength values and mean fiber area in men. Most subjects had single atrophic fibers; groups of atrophic fibers were less common. Internal nuclei and splitting were seen in about half of the subjects. The activity of citrate synthase was low, but normal for glycolytic enzymes.
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PMID:Muscle adaptive changes in post-polio subjects. 271 Nov 35