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Biomedical subjects

P Sacco

Publications and source records attributed to P Sacco.

At least 19 recordsLinked to original sources
PubMed2006

Greater muscle damage induced by fast versus slow velocity eccentric exercise.

Debate exists concerning the effect of contraction velocity on muscle damage, and few human studies have yet to address this issue. This study examined whether the velocity of eccentric exercise affected the magnitude of muscle damage. Twelve untrained subjects performed a series of slow velocity isokinetic eccentric elbow flexions (SV: 30 degrees . s (-1)) of one arm and a fast velocity exercise (FV: 210 degrees . s (-1)) of the other arm, separated by 14 days. In order to standardise the time under tension (120 s) for the two conditions, the number of muscle actions for SV was 30 and 210 for FV. Criterion measures consisted of maximal voluntary torque for isometric, concentric (4 velocities) and eccentric contractions (2 velocities), range of motion (ROM) and relaxed elbow joint angle (RANG), upper arm circumference, muscle soreness and plasma creatine kinase (CK) activity. Measures were taken before, immediately after, 0.5 hour and 24 - 168 hours (240 hours for CK) after each eccentric exercise protocol, and changes in the measures over time were compared between FV and SV by two-way repeated measures ANOVA. Both protocols resulted in significant decrements in isometric and dynamic torque (p < 0.01), but FV showed significantly (p < 0.05) greater reductions over time ( approximately 55 %) and a slower recovery compared to SV ( approximately 30 %). Significantly (p < 0.05) larger decreases in, and delayed recovery of, ROM and RANG were evident after FV compared to SV. FV had significantly (p < 0.05) larger increases in upper arm circumference and soreness compared to SV, and peak plasma CK activity was 4.5-fold greater (p < 0.05) following FV than SV. These results suggest that, for the same time under tension, fast velocity eccentric exercise causes greater muscle damage than slow velocity exercise in untrained subjects.

Adult↗
PubMed2004

Hypertelorism, ptosis, and myopia associated with drug-resistant epilepsy, mental delay, growth deficiency, ectodermal defects, and osteopenia.

We report a 30-year-old woman with hypertelorism, ptosis, and myopia associated with drug-resistant epilepsy (DRE, Lennox-Gastaut syndrome), mental delay, growth deficiency, ectodermal defects, and osteopenia. To the best of our knowledge, this patient has an unusual combination of symptoms not previously described, associated with severe central nervous system dysfunction. The ectodermal defects were present in a very intriguing form, were difficult to diagnose, and did not conform to any classification or previous description.

Adult↗
PubMed2004

Phytoextraction of heavy metals by canola (Brassica napus) and radish (Raphanus sativus) grown on multicontaminated soil.

Phytoextraction can provide an effective in situ technique for removing heavy metals from polluted soils. The experiment reported in this paper was undertaken to study the basic potential of phytoextraction of Brassica napus (canola) and Raphanus sativus (radish) grown on a multi-metal contaminated soil in the framework of a pot-experiment. Chlorophyll contents and gas exchanges were measured during the experiment; the heavy metal phytoextraction efficiency of canola and radish were also determined and the phytoextraction coefficient for each metal calculated. Data indicated that both species are moderately tolerant to heavy metals and that radish is more so than canola. These species showed relatively low phytoremediation potential of multicontaminated soils. They could possibly be used with success in marginally polluted soils where their growth would not be impaired and the extraction of heavy metals could be maintained at satisfying levels.

Brassica napus↗
PubMed2003

18q-syndrome and ectodermal dysplasia syndrome: description of a child and his family.

The 18q- syndrome [MIM #601808] is a terminal deletion of the long arm of chromosome 18. The most common deletion extends from region q21 to qter. We report here a nine-year-old boy possessing a simple 18q- deletion who had abnormalities of the brain, skull, face, tooth, hair, bone, and skin, plus joint laxity, tongue palsy, subtle sensoneural deafness, mental and speech delay, attention deficit hyperactivity disorder (ADHD), tic, and restless legs syndromes. His karyotype was 46, XY, del (18)(q21.31-qter). The size of the deletion was approximately 45 cM. Most of these abnormalities were not explained by the 18q- deletion. The family pedigree suggested the presence of a subtle involvement of ectodermal and/or mesodermal structures. Karyotypes of the other family members were normal.

Abnormalities, Multiple↗
PubMed2002

The effects of therapeutic massage on delayed onset muscle soreness and muscle function following downhill walking.

This study Investigated the effects of a therapeutic massage on delayed onset muscle soreness and muscle function following downhill walking. Eight male subjects performed a 40-min downhill treadmill walk loaded with 10% of their body mass. A qualified masseur performed a 30-min therapeutic massage to one limb 2 hours post-walk. Muscle soreness, tenderness, isometric strength, isokinetic strength, and single leg vertical jump height were measured on two occasions before, and 1, 24, 72 and 120 hours post-walk for both limbs. Subjects showed significant (p < 0.004) increases in soreness and tenderness for the non-massaged limb 24 hours post-walk with a significant (p < 0.001) difference between the two limbs. A significant reduction In isometric strength was recorded for both limbs compared to baseline 1 hour post-walk. Isokinetic strength at 60 degrees/sec and vertical jump height were significantly lower for the massaged limb at 1 and 24 hours post-walk. No significant differences were evident in the remaining testing variables. These results suggest that therapeutic massage may attenuate soreness and tenderness associated with delayed onset muscle soreness. However it may not be beneficial in the treatment of strength and functional declines.

Adult↗
PubMed2002

Responses of human elbow flexor muscles to electrically stimulated forced lengthening exercise.

This study developed an electrical stimulation model for human elbow flexors to examine eccentric exercise-induced muscle damage and adaptation. Male students (n=17) were randomly placed into one of two groups; isometric (ES-ISO, n=8) and eccentric (ES-ECC, n=9). The elbow joint was fixed at 90 degrees (1.57 rad) and the elbow flexors stimulated percutaneously by an electronic muscle stimulator for 5 s through two electrodes placed over the muscles for ES-ISO. In ES-ECC, the muscles were stimulated similarly to the ES-ISO, but the elbow joint was forcibly extended from an elbow flexed (90 degrees 1.57 rad) to a full-extended position (180 degrees, 3.14 rad) in 3 s. Maximal voluntary isometric force, range of motion, upper arm circumference, muscle thickness by ultrasonography, muscle soreness, plasma creatine kinase and aspartate aminotransferase activities were assessed before and for 4 days after exercise. ES-ECC produced significantly larger changes in all criterion measures compared with ES-ISO (P < 0.01). These findings confirmed that eccentric muscle actions induced muscle damage, but isometric contractions resulted in little or no damage. Six subjects from the ES-ECC group repeated the same eccentric exercise (ECC2) 2 weeks after the first bout (ECC1), and changes in the criterion measures were compared between the bouts. Changes in all criterion measures after ECC2 were significantly smaller than ECC1 (P < 0.01). These results suggest that the first eccentric exercise produced a protective effect against muscle damage in the subsequent eccentric exercise bout, which does not involve adaptations in the central nervous system.

Adaptation, Physiological↗
PubMed2001

The repeated bout effect of reduced-load eccentric exercise on elbow flexor muscle damage.

In this study we investigated the extent to which an initial eccentric exercise consisting of two (2ECC) or six maximal eccentric actions (6ECC) of the elbow flexors would produce a similar effect to 24 maximal eccentric actions (24ECC), on a second bout of 24ECC performed 2 weeks later. Male students (n = 34) were assigned to one of three groups, and with their non-dominant arm performed either 2ECC (n = 12), 6ECC (n = 10), or 24ECC (n = 12) as a first bout of exercise. Two weeks later all groups performed 24ECC. Maximal isometric strength, range of motion, upper arm circumference, muscle soreness, plasma creatine kinase activity and myoglobin concentration were assessed before, immediately after, and for 4 days after exercise. Changes in all variables were compared between the bouts and groups by a two-way repeated measures analysis of variance. All variables changed significantly (P< 0.05) after 2ECC, 6ECC, and 24ECC, but the amount of change after 2ECC and 6ECC was significantly smaller (P<0.05) than both 6ECC and 24ECC, and 24ECC, respectively. After the second bout, the 6ECC and 24ECC groups showed a profound repeated bout effect, and no significant differences were found between the groups. All variables except muscle soreness were significantly (P< 0.05) larger after the second bout for the 2ECC group, however the changes observed after 24ECC were significantly smaller (P < 0.01) than those observed after the first 24ECC of the 24ECC group. These results suggest that it is not necessary to conduct a high number of eccentric actions in the first bout to elicit a repeated bout effect in a subsequent bout performed some time later.

Adolescent↗
PubMed2001

How long does the protective effect on eccentric exercise-induced muscle damage last?

PURPOSE: One bout of eccentric exercise produces an adaptation that reduces muscle damage in subsequent bouts. Because it is not known how long this adaptation lasts, the present study investigated the maximal length of the attenuated changes in muscle damage indicators after high-force eccentric exercise. METHODS: Male students (N = 35) were placed into three groups and performed two bouts of eccentric exercise of the nondominant elbow flexors separated by either 6 (N = 14), 9 (N = 11), or 12 (N = 10) months. Maximal isometric force (MIF), range of motion (ROM), upper arm circumference (CIR), muscle soreness (SOR), and plasma creatine kinase activity (CK) were measured before and for 5 d after exercise. Magnetic resonance (MR) images of the transverse and longitudinal scans of the upper arm were taken 4 d after exercise. Changes in the criterion measures were compared between the first and second bouts and between groups by a two-way repeated measures ANOVA. RESULTS: A faster recovery in MIF was evident after a second bout performed at 6 or 9 months, and reduced SOR as well as smaller increases in CIR, CK, and T2 relaxation time of MR images also occurred after the second exercise bout at 6 months compared with initial responses. No significant differences between the bouts were found for ROM, and the 12-month group did not show any repeated bout effect. CONCLUSION: These results show that the repeated bout effect for most of the criterion measures lasts at least 6 months but is lost between 9 and 12 months.

Adolescent↗
PubMed2000

The role of the supplementary motor area in externally timed movement: the influence of predictability of movement timing.

A significant role in the planning and preparation for voluntary movement has been ascribed to secondary motor areas located on the medial wall of the cerebral hemispheres, and in particular to the supplementary motor area (SMA). Within the SMA, rostral and caudal subdivisions have been described, and differential roles have been attributed to these regions in relation to movement planning, preparation and execution. We have used functional magnetic resonance imaging (fMRI) to investigate the role of the SMA in the timing of movement execution, by recording the fMRI signal from mesial pre-motor areas and primary sensorimotor cortex (SM1) during the execution of a simple motor task externally cued at predictable (regular) and unpredictable (irregular) time intervals. The mean rate of movement was matched in both experiments. There was a greater activation of caudal than rostral SMA with both predictably and unpredictably cued movements, and a doubling of the signal when the timing of the motor response was unpredictable. In contrast, there was no difference in the activation of primary sensorimotor cortex with the two tasks. The data demonstrate that the caudal SMA has an important role in the execution of externally cued movements. The results also suggest a greater role for this region in the performance of unpredictably timed compared with predictably timed movements, however a model is proposed (based on electrophysiological data) which shows how the difference in functional signal in these two situations can be explained on the basis of a difference in the time course of neuronal activation in the SMA, rather than in the overall degree of activation.

Adult↗
PubMed2000

Changes in corticomotor excitability after fatiguing muscle contractions.

To investigate whether the type and duration of activity influences corticomotor excitability following fatiguing exercise, we compared motor evoked potential (MEP) responses of the biceps brachii to transcranial magnetic stimulation (TMS) during recovery from two different exercise regimens. Responses were recorded in both the resting state and during a weak contraction. Ten subjects performed a 60-s maximal voluntary contraction (MVC) and, on a subsequent occasion, a sustained 20% MVC to the point of exhaustion. Resting MEP amplitude declined following maximal and submaximal protocols, reaching 34% and 31% of pre-exercise means, respectively (P < 0.001 for both). In contrast, mean facilitated MEP amplitude showed a smaller and more transient decrement following the sustained submaximal effort (64%; P < 0.05), but not the 60-s MVC. Abolition of the postexercise depression in resting MEP amplitude by a weak tonic contraction indicates that decreases in excitability at the spinal level contribute to the reduced corticomotor excitability observed after fatiguing exercise.

Action Potentials↗
PubMed1999

Differences in functional magnetic resonance imaging of sensorimotor cortex during static and dynamic finger flexion.

Functional magnetic resonance imaging (fMRI) studies of the human motor system have commonly used movement paradigms which contain a dynamic component; however, the relationship between the fMRI signal for motor tasks with and without a dynamic component is not known. We have investigated the relationship between the fMRI signal during a static finger flexion task and during dynamic finger flexion at 1-3 Hz, each at two levels of force (5% and 10% of maximum voluntary contraction). A small fMRI response could be recorded from only a few subjects during the static tasks. In contrast, a substantial fMRI response occurred during dynamic tasks in all subjects at both levels of force. The fMRI response was not significantly correlated with force or movement rate during the dynamic tasks. It is concluded that the factors responsible for generating an fMRI response are fundamentally different during steady contractions compared to those involving a dynamic component, and that the fMRI signal may be more sensitive to changes in the pattern of neural activation rather than the ongoing firing rate or extent of activation.

Adult↗
PubMed1999

Corticomotor excitability and perception of effort during sustained exercise in the chronic fatigue syndrome.

OBJECTIVE: We have investigated the possibility of a central basis for the complaints of fatigue and poor exercise tolerance in subjects with chronic fatigue syndrome (CFS). METHODS: Transcranial magnetic stimulation of the motor cortex was used to measure sequential changes in motor evoked potential (MEP) amplitude, post-excitatory silent period (SP) duration and twitch force of the biceps brachii muscle during a 20% maximum isometric elbow flexor contraction maintained to the point of exhaustion. Ten patients with post-infectious CFS and 10 age- and sex-matched control subjects were studied. Results were analysed using non-parametric repeated measures analysis of variance (Friedman's test) and Mann-Whitney U-tests for intra- and inter-group comparisons respectively. RESULTS: Mean endurance time for the CFS group was lower (13.1+/-3.2 min, mean +/- SEM) than controls (18.6+/-2.6 min, P < 0.05) and CFS subjects reported higher ratings of perceived exertion. During the exercise period MEP amplitude and SP duration increased in both groups but to a lesser extent in CFS subjects. Interpolated twitch force amplitude also increased during exercise, being more pronounced in CFS subjects. CONCLUSION: The findings are in keeping with an exercise-related diminution in central motor drive in association with an increased perception of effort in CFS.

Adult↗
PubMed1998

The effects of eccentric exercise on neuromuscular function of the biceps brachii.

This study investigated the effects of a bout of exercise-induced muscle damage on strength and motor skill of the elbow flexor muscles. Eight subjects performed 35 maximal isokinetic eccentric elbow flexions at 90 degrees sec(-1) and maximal voluntary contraction (MVC) force, surface electromyography (EMG), plasma creatine kinase (CK) and tracking error associated with a one-dimensional elbow flexion/extension visuomotor pursuit task were studied at intervals up to 28 days after exercise. Subjects showed a post-exercise decline in MVC (mean = 63 +/- 11% (s.d.) of pre-exercise after 1 day, p<0.02) and were still significantly weaker at 21 days. The delayed-onset plasma CK rise and the absence of any quantitative change in surface EMG suggest that the observed weakness was related to muscle fibre damage. Tracking performance decreased in all subjects with the greatest tracking error occurring 1 day post-exercise (mean = 127% +/- 20% of control value, p<0.02). There was a significant negative correlation between strength and tracking performance following exercise (r2 = 0.724). The results demonstrate that performance in activities requiring fine motor control will be impaired for a number of days following a bout of damaging exercise.

Adult↗
PubMed1998

The corticomotor representation of upper limb muscles in writer's cramp and changes following botulinum toxin injection.

Transcranial magnetic stimulation was used to investigate the properties of the corticomotor pathway and to map the primary motor cortex projection to hand and forearm muscles during a sustained isometric contraction in a group of subjects with writer's cramp of varying duration. Corticomotor threshold, motor evoked potential amplitude and latency, and silent-period duration were normal on both sides in all subjects. The maps of the corticomotor projection were displaced relative to normal in all subjects, and in some cases were distorted in shape, with extensions of the lateral borders and the emergence of almost discrete secondary motor areas. The degree of map distortion and displacement was greatest in subjects with long-standing writer's cramp (> 5 years), and was bilateral in some cases. Injection of botulinum toxin into affected muscles demonstrated that the alterations in map topography were not fixed, and could be temporarily reversed during the period when the clinical effects of the injection were greatest, with the maps returning to their original positions as the effects of the injection wore off. It is concluded from this study that there are slowly evolving reorganizational changes in the primary motor cortex in writer's cramp, and that these changes may be secondary to altered afferent inputs from both clinically affected and unaffected muscles.

Adult↗