Gene/Protein Disease Symptom Drug Enzyme Compound
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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

Nine bodybuilders performed heavy-resistance exercise activating the quadriceps femoris muscle. Intermittent 30-s exhaustive exercise bouts comprising 6-12 repetitions were interspersed with 60-s periods for 30 min. Venous blood samples were taken repeatedly during and after exercise for analyses of plasma free fatty acid (FFA) and glycerol concentration. Muscle biopsies were obtained from the vastus lateralis muscle before and after exercise and assayed for glycogen, glycerol-3-phosphate, lactate and triglyceride (TG) content. The activities of citrate synthase (CS), lactate dehydrogenase, hexokinase (HK), myokinase, creatine kinase and 3-hydroxyacyl-CoA dehydrogenase (HAD), were analysed. Histochemical staining procedures were used to assess fibre type composition, fibre area and capillary density. TG content before and after exercise averaged (SD) 23.9 (13.3) and 16.7 (6.4) mmol kg-1 dry wt. The basal triglyceride content varied sixfold among individuals and the higher the levels the greater was the change during exercise. The glycogen content decreased (P less than 0.001) from 690 (82) to 495 (95) mmol kg-1 dry wt. and lactate and glycerol-3-phosphate increased (P less than 0.001) to 79.5 (5.5) and 14.5 (7.3) mmol kg-1 dry wt., respectively, after exercise. The HK and HAD/CS content respectively correlated with glycogen or TG content at rest and with changes in these metabolites during exercise. FFA and glycerol concentrations increased slightly (P less than 0.001) during exercise. Lipolysis may, therefore, provide energy during heavy-resistance exercise of relatively short duration. Also, storage and utilization of intramuscular substrates appear to be influenced by the metabolic profile of muscle.
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PMID:Glycogen and triglyceride utilization in relation to muscle metabolic characteristics in men performing heavy-resistance exercise. 228 98

1. The activities of phosphofructokinase (PFK), citrate synthetase (CS), lactate dehydrogenase (LDH), 3-hydroxyacyl-CoA dehydrogenase (ACDH) and cytochrome-c oxidase(Cyt-ox) in the calf muscle tissue were compared in subjects with intermittent claudication (n = 38) and controls (n = 20). The activities of CS, ACDH and Cyt-ox were increased and the activity of Cytox was positively correlated to the maximal walking distance (MWD) in the patients. 2. Thirty-three patients with intermittent claudication were randomized to three treatment groups: (1) operative surgery, (2) operative surgery supplemented with physical training and (3) physical training alone. Before and after 6-12 months of treatment, symptom-free walking distance (SFWD), MWD, ankle-brachial blood pressure quotient (ankle index), maximal plethysmographic calf blood flow (MPBF) and the activities of PFK, CS, LDH, ACDH and Cyt-ox were measured. 3. SFWD and MWD increased in all three groups. Ankle index and MPBF increased in groups 1 and 2, but were unchanged in group 3. The activities of Cyt-ox and CS decreased with operation, but the activity of Cyt-ox was further augmented with training in group 3. Overall, the change in ankle index explained 80-90% of the variability in walking performance. In a separate analysis, the increased activity of Cyt-ox in group 3 was positively correlated to, and explained 31% of the variability in, the improvement in SFWD. 4. These findings indicate that both physical activity and a reduced calf blood flow are necessary conditions for the enzymatic adaptation to take place. A causal relationship between metabolic adaptation in the muscle tissue and walking performance is suggested.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Muscle enzyme adaptation in patients with peripheral arterial insufficiency: spontaneous adaptation, effect of different treatments and consequences on walking performance. 255 5

Effects of spinal cord transection in 2-wk-old cats on the metabolic, histochemical, and fatigue properties of a fast- and a slow-twitch muscle were determined. Chronic (6-12 mo) spinalization (Sp) resulted in an increased ratio of fast-twitch, oxidative-glycolytic (FOG) to slow-twitch, oxidative (SO) fibers in soleus (SOL). In medial gastrocnemius (MG), Sp produced a histochemical profile suggesting that fast fibers were increased at the expense of slow fibers. Changes in biochemical markers for oxidative (citrate synthase) and glycolytic (GPD) potential were consistent with the histochemical findings. The fatigue index of Sp MG and SOL remained normal and was consistent with the type and degree of fiber type change. Daily treadmill exercise did not markedly alter any of the adaptations. The metabolic and fatigue properties of skeletal muscle of Sp cats are consistent with the view that as some fibers develop "faster-like" characteristics, the oxidative and the glycolytic potential is also enhanced. As was true of the contractile properties and related biochemical data, the changes observed suggest that significant changes occurred within as well as across fiber types. These data, in conjunction with that of chronic EMG recordings, provide evidence that there is a relative independence of both the oxidative potential and the fatigability of a muscle relative to its quantity of activation.
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PMID:Relative independence of metabolic enzymes and neuromuscular activity. 673 19

Hyperthyroidism is associated with exercise intolerance. Previous research, however, has shown that cardiac output is either normal or enhanced during exercise in the hyperthyroid state. We therefore hypothesized that blood flow to working skeletal muscle is augmented in hyperthyroid animals during in vivo submaximal exercise and, consequently, that noncardiovascular factors are responsible for intolerance to exercise. To test this hypothesis, rats were made hyperthyroid (Hyper) over 6-12 wk with injections of triiodothyronine (300 micrograms/kg). Hyperthyroidism was evidenced by left ventricular hypertrophy [euthyroid (Eut), 2.12 +/- 0.05 mg/g body wt; Hyper, 2.78 +/- 0.06; P < 0.005], 25-60% increases in citrate synthase activities in Hyper hindlimb muscles over those of Eut rats, and higher preexercise heart rates (Eut, 415 +/- 18 beats/min; Hyper, 479 +/- 19; P < 0.025). Regional blood flows were determined by the radiolabeled microsphere method, preexercise, and at 1-2 min of treadmill running at 15 m/min (0% grade). Total hindlimb muscle blood flow preexercise was unaffected (Eut, 31 +/- 4 ml.min-1.(100) g-1, n = 11; Hyper, 40 +/- 6, n = 9; not significant) but was higher (P < 0.025) in Hyper (127 +/- 17, n = 9) compared with Eut (72 +/- 11, n = 9) during treadmill running. During exercise, flows to individual muscles and muscle sections were approximately 50-150% higher in Hyper compared with Eut rats. Visceral blood flows were largely similar between groups. These findings indicate that hyperthyroidism is associated with augmented blood flow to skeletal muscle during submaximal exercise. Thus hypoperfusion of skeletal muscle does not account for the poor exercise tolerance characteristic of hyperthyroidism.
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PMID:Effects of hyperthyroidism on muscle blood flow during exercise in rats. 784 Feb 80

Sera collected from apparently healthy 6-12-month-old cats (n = 31) presented to the Society for the Prevention of Cruelty to Animals Veterinary Clinic in Bloemfontein for neutering were tested for antibodies reactive to Bartonella henselae (Houston-1 strain) by indirect fluorescent antibody testing. Whole blood collected from the cats was used in isolation experiments and subsequent identification of Bartonella species was based on comparison of the nucleotide base sequence of polymerase chain reaction-amplified citrate synthase gene fragments. While none of the cats had antibodies reactive with B. henselae at titres > or =1/64, an organism with a partial citrate synthase gene sequence identical to that of B. henselae (Houston-1) was isolated from 1 cat.
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PMID:Isolation of Bartonella henselae from a serologically negative cat in Bloemfontein, South Africa. 1085 38