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At least 955 records · Page 53Linked to original sources
PubMed2005

Amphetamine fails to facilitate motor performance and to enhance motor recovery among stroke patients with mild arm paresis: interim analysis and termination of a double blind, randomised, placebo-controlled trial.

PURPOSE: To assess the effects of d-amphetamine on motor facilitation and recovery in stroke patients with mild arm paresis receiving the Arm Ability training. METHODS: Thirty-one stroke patients with mild arm paresis were randomly assigned to either (a.) receiving placebo or (b.) d-amphetamine twice a week 2 hours before Arm Ability training sessions for three weeks. MAIN OUTCOME MEASURE: time needed to perform TEMPA tasks, a measure of upper extremity performance reflecting everyday life tasks. Secondary measures: aimed movements, tapping, and a 10 m walkway as well as motor performance during training sessions. RESULTS: The interim efficacy analysis of 26 stroke patients who completed the study intervention showed overall arm motor recovery both from pre to post test after 3 weeks of training and from pre test to follow-up 1 year later. No superior effect of d-amphetamine over placebo could be substantiated for either motor facilitation during training or motor recovery (post training or long-term). D-amphetamine exerted mild effects on blood pressure. Serious adverse events were not observed. CONCLUSIONS: d-Amphetamine failed to facilitate motor performance during training sessions, to promote skill acquisition with training tasks, and most importantly to enhance motor recovery among patients with mild arm paresis after stroke.

Aged↗
PubMed1999

Reliability and effects of arm dominance on upper extremity isokinetic force, work, and power using the closed chain rider system.

OBJECTIVE: The purpose of our study was to assess the reliability of the Closed Chain Rider System between exercise sessions and to determine the effects of arm dominance using muscle force, work, and power measures during closed chain chest-press exercise. DESIGN AND SETTING: Sitting subjects underwent identical testing on 2 occasions and performed 5 reciprocal chest-press movements at speeds of 51 and 76 cm/s. SUBJECTS: Thirty-eight healthy college students. MEASUREMENTS: Average force, total work, average power, and linear range of motion were recorded. Reliability was evaluated by calculating intraclass correlation coefficients. Mean differences between the dominant and nondominant arms for the measured variables were analyzed by dependent t tests. RESULTS: For both the dominant and nondominant arms at the 51 and 76 cm/s speeds, reliabilities of average force (range = 0.85 to 0.91), total work (range = 0.88 to 0.92), and average power (range = 0.86 to 0.89) were clinically acceptable. The dominant arm produced significantly greater average force, total work, and average power compared with the nondominant arm. CONCLUSIONS: Our results provide clinically useful information about the reliability of force, work, and power measures during multijoint bilateral chest-press movement. Clinicians should be aware of measured differences between dominant and nondominant arms.

Journal Article↗
PubMed1989

Localization of HeLa cell tumor-suppressor gene to the long arm of chromosome II.

Cytogenetic and molecular genetic analyses of human intraspecific HeLa x fibroblast hybrids have provided evidence for the presence of a tumor-suppressor gene(s) on chromosome 11 of normal cells. In the present study, we have carried out extensive RFLP analysis of various nontumorigenic and tumorigenic hybrids with at least 50 different chromosome 11-specific probes to determine the precise location of this tumor-suppressor gene(s). Two different hybrid systems, (1) microcell hybrids derived by the transfer of a normal chromosome 11 into a tumorigenic HeLa-derived hybrid cell and (2) somatic cell hybrids derived by the fusion of the HeLa (D98OR) cells to a retinoblastoma (Y79) cell line, were particularly informative. The analysis showed that all but one of the nontumorigenic hybrid cell lines contained a complete copy of the normal chromosome 11. This variant hybrid contained a segment of the long arm but had lost the entire short arm of the chromosome. The tumorigenic microcell and somatic cell hybrids had retained the short arm of the chromosome but had lost at least the q13-23 region of the chromosome. Thus, these results showed a perfect correlation between the presence of the long arm of chromosome 11 and the suppression of the tumorigenic phenotype. We conclude therefore that the gene(s) involved in the suppression of the HeLa cell tumors is localized to the long arm (q arm) of chromosome 11.

Cell Line↗
PubMed1988

Effects of sphygmomanometer type and position of the arm on blood pressure measurement.

Random zero and standard sphygmomanometers were compared in a balanced study performed by 36 members of a General Practitioner Clinical Research Group. In addition the influence of arm position, supported versus dependent, was examined. There was minimal difference between the mean blood pressures measured by the two sphygmomanometers, although the results from the random zero were more variable. The mean blood pressures with the arm supported were consistently lower than with the arm dependent: 127/79 mmHg arm supported vs 131/83 mmHg arm dependent. It is recommended that the position of the arm should be standardised to that of being supported roughly horizontally at heart level. The random zero machine should be used for clinical trial work where the elimination of observer bias is important, and when proper training of observers can be undertaken.

Blood Pressure Determination↗
PubMed1986

The translational efficiency of tRNA is a property of the anticodon arm.

We have reciprocally transplanted the anticodon arm sequences of a set of amber suppressor tRNA genes, using recombinant DNA techniques. By this means, a very efficient suppressor may be converted to a poor one, and the poorest tRNA to the efficiency of the best one. In tRNA molecules of normal 2 degrees and 3 degrees structure, the suppressor efficiencies of different composite tRNAs having the same anticodon arm sequence are approximately the same. Large numbers of simultaneous changes throughout the rest of the molecule do not affect the efficiency. Selective nucleotide modification as a result of varied anticodon arm sequences cannot explain these efficiencies. Efficiencies are also unlikely to differ because of selective aminoacylation. Measurement of in vivo tRNA shows, however, that tRNA levels do vary if the anticodon arm sequence is changed. If tRNA levels are normalized, the anticodon arm effect on the translational efficiency remains. Therefore, different anticodon arms, all of normal secondary structure, are not equivalent in translation. The most efficient sequences in this series resemble those found in natural tRNAs associated with similar anticodons, as is proposed in the extended anticodon theory (Yarus, M. (1982) Science 218, 646-652). These molecules also provide some information on the specificity of nucleotide modification enzymes and on determinants of the steady-state tRNA level.

Anticodon↗
PubMed1983

[Recent advances in studies of rat memory in the radial-arm maze].

Radial-arm maze task provides a new experimental paradigm for assessing animal memory, which is different from those of the traditional mazes such as T- and Y-mazes. Radial-arm maze consists of a central platform and multiple (usually 8) arms extending radially from the platform. The animal (the rat in the most cases) is trained for one trial a day to eat pellets placed in the end of each arm, and after trainings for 1-2 weeks, it becomes to obtain the pellets efficiently, i.e., without reentering the arms already visited in that trial. The effective performance in this task is based on the following two kinds of memory components: "reference memory", which includes information about the configuration of extramaze (mainly visual) stimuli, and "working memory", which incorporates the chosen arms in that trial. The information in the reference memory is effective across the trials, whereas that in the working memory is only in a particular trial. A series of experiments have demonstrated that the septo-hippocampal system is involved in the performance of this task, especially in the working memory component. It has also been reported that central cholinergic system plays an important role in the performance. Recently, the task is employed as a useful tool in such research areas as the experimental gerontology and the behavioral teratology.

Aging↗
PubMed1984

Differences between right and left arm blood pressures in the elderly.

Recommendations vary on whether blood pressures should be measured in the right or in the left arm because no frequency distributions for a pressure difference between the arms exist. We took a total of 12 blood pressure determinations in both arms of 174 elderly persons and analyzed the data by a least-squares components of variance method. The mean difference between the arms (right minus left) was 0.93 mm of mercury for systole and 0.70 mm of mercury for diastole. For systole the proportion of persons having arm pressure differences exceeding 10 mm of mercury is 1.4% and that exceeding 7.5 mm of mercury is 6.5%. For most people, the pressure difference between the arms is small.

Aged↗
PubMed1983

Arm crank vs handrim wheelchair propulsion: metabolic and cardiopulmonary responses.

The handrim propulsion system of most manual wheelchairs has been shown to be inefficient and stressful to the cardiovascular and pulmonary systems. Arm crank propulsion has been suggested to reduce these stresses. In order to compare conventional handrim wheelchair propulsion to arm crank type wheelchair propulsion, 16 volunteers (9 able-bodied, 7 wheelchair-dependent) operated both wheelchairs over level tiled and carpeted test courses at 3km.hr-1. The arm crank propelled wheelchair was operated in 3 gear ratios: low, medium and high. Exercise bouts were 5 minutes in duration. During the final minute of each test, oxygen uptake (VO2), net locomotive energy cost (NLEC), pulmonary ventilation (VE) and heart rate (HR) were monitored. Subjects exhibited significantly lower magnitude of these physiologic responses during arm crank wheelchair propulsion relative to handrim wheelchair propulsion for all gear drive ratios. Average percent differences were 30% and 32% for VO2; 50% and 50% for NLEC; 27% and 34% for VE; and 16% and 19% for HR on the tiled and carpeted test surfaces, respectively. From these data we conclude that arm crank wheelchair propulsion is less strenuous than conventional handrim wheelchair propulsion and that arm crank propulsion systems should be considered as a possible means to improve wheelchair design.

Adult↗
PubMed1981

The blood flow through the "resting" arm during hand-grip contractions.

These experiments were designed to add information about the control of the circulation in the contralateral arm during isometric hand-grip contractions. The existing evidence came from two laboratories and was in conflict. The most recent data claimed that there is an inevitable increase in blood flow through the contralateral arm and that it is neurogenically controlled, while some degree of electromyographic activity was not associated with an increase in the blood flow. In the present experiments, the blood flow and the oxygen uptake over the arm were first "calibrated" against the electromyographic activity during isometric contractions at known low tensions. In steady state conditions, there were direct, linear relationships between all four measurements. The "calibrated" arm then became the contralateral (resting) arm, while strong isometric contractions were held by the other hand. Of 12 subjects examined, half showed no increase in blood flow or electromyographic activity. The other six subjects all showed some muscular activity (electromyogram) in the contralateral arm which was always associated with an increase in blood flow and oxygen uptake. Not all those findings fitted the "calibration" closely; the problems of this approach are discussed.

Adult↗
PubMed1980

Regeneration of reversed aneurogenic arms of the axolotl.

Aneurogenic arms of young axolotls were implanted into the flank as heterotopic autografts with reversed proximo-distal orientation. The formerly proximal ends of such arms regressed to a variable extent, and then either regenerated or could do so following a second amputation. The regenerate always contained a complete sequence of skeletal elements between the adjacent stump skeleton and terminal digits, being a mirror image of the implanted arms with identical transverse axes but an opposed proximo-distal axis. Many reversed arms also regenerated fingers from the implanted hand. Identical results were obtained from reversed arms of control larvae, confirming previous studies on reversed well-innervated arms. Nerves are not required for the establishment of a new proximo-distal axis, therefore, and probably have no influence on the determination of any limb axis. Morphogenesis of the regenerate is clearly related to the position along the proximo-distal axis where the blastema originates. Although this axis is reasonably envisaged in terms of a gradient, its polarity is ignored during regeneration.

Ambystoma↗
PubMed1996

Effect of body position on isometric arm lifting strength.

The purpose of this study was to examine the influence of three different body positions on isometric arm lifting strength. Thirty students aged between 20 and 27 years volunteered as subjects for the study. A force Evaluation and Testing System (FET 5000) was used to measure the arm lifting strength in the supine, sitting, and standing positions. Average force of each body position was determined by the mean of two trials. At the same time, electromyographic activity of bilateral biceps brachii muscles was measured during maximal voluntary isometric arm lifting. Repeated measures analysis of variance was used to analyze the effects of body positions on the amount of average force value and integrated electromyographic (IEMG) values during isometric arm lifting. The results showed that the highest mean lifting strength was recorded in the sitting position for both males and females. Significant difference in arm lifting strength was found between each body position. Differences in force were elicited more easily between the female and male subjects. However, the average IEMG values were not significantly correlated with the force produced in arm lifting. Nevertheless, this study supports the conclusion that body position did influence the production of isometric elbow flexors strength. We conclude, therefore, that body position must be considered during rehabilitation of upper extremities.

Adult↗
PubMed1996

Differences in the interaction of Escherichia coli RNase P RNA with tRNAs containing a short or a long extra arm.

The phosphorothioate footprinting technique was applied to the investigation of phosphate moieties in tRNA substrates involved in interactions with M1 RNA, the catalytic subunit of Escherichia coli RNase P. In general agreement with previous data, all affected sites were localized in acceptor stem and T arm. But the analyzed examples for class I (Saccharomyces cerevisiae pre-tRNA(Phe) with short variable arm) and class II tRNAs (E. coli pre-tRNA(Tyr) with large variable arm) revealed substantial differences. In the complex with pre-tRNA(Phe), protection was observed at U55, C56, and G57, along the top of the T loop in the tertiary structure, whereas in pre-tRNA(Tyr), the protected positions were G57, A58, and A59, at the bottom of the T loop. These differences suggest that the size of the variable arm affects the spatial arrangement of the T arm, providing a possible explanation for the discrepancy in reports about the D arm requirement in truncated tRNA substrates for eukaryotic RNase P enzymes. Enhanced reactivities were found near the junction of acceptor and T stem (U6, 7, 8 in pre-tRNA(Phe) and G7, U63, U64 in pre-tRNA(Tyr)). This indicates a partial unfolding of the tRNA structure upon complex formation with RNase P RNA.

Base Sequence↗
PubMed1998

[Arm folding--an overview].

The literature concerning arm folding is reveiwed. This analysis could be based on 121 populations. In addition to this the paper discusses incidence, sex, age differences and genetical problems including twinning. The incidence of left arm folding ranges from 20% to 65% (mean value 54%). The review shows a predominance of the left-type in Europe. Age and sex differences are only small. Between arm folding and handedness no relationship could be found, and only a very weak one between arm folding and hand clasping. 13 authors examined arm folding in families, and 2 in twins. The family data suggest that arm folding may be under a certain genetic control, yet it is clear that no simple genetic model concerning the inheritance can be assumed. Monozygotic as well as dizygotic twins show a low rate of concordance, and the frequencies of R-R, R-L and L-L pairs in monozygotic and dizygotic twins show a binomial distribution.

Female↗
PubMed1998

Patterns of arm muscle activation involved in octopus reaching movements.

The extreme flexibility of the octopus arm allows it to perform many different movements, yet octopuses reach toward a target in a stereotyped manner using a basic invariant motor structure: a bend traveling from the base of the arm toward the tip (Gutfreund et al., 1996a). To study the neuronal control of these movements, arm muscle activation [electromyogram (EMG)] was measured together with the kinematics of reaching movements. The traveling bend is associated with a propagating wave of muscle activation, with maximal muscle activation slightly preceding the traveling bend. Tonic activation was occasionally maintained afterward. Correlation of the EMG signals with the kinematic variables (velocities and accelerations) reveals that a significant part of the kinematic variability can be explained by the level of muscle activation. Furthermore, the EMG level measured during the initial stages of movement predicts the peak velocity attained toward the end of the reaching movement. These results suggest that feed-forward motor commands play an important role in the control of movement velocity and that simple adjustment of the excitation levels at the initial stages of the movement can set the velocity profile of the whole movement. A simple model of octopus arm extension is proposed in which the driving force is set initially and is then decreased in proportion to arm diameter at the bend. The model qualitatively reproduces the typical velocity profiles of octopus reaching movements, suggesting a simple control mechanism for bend propagation in the octopus arm.

Animals↗
PubMed2003

Thoracic outlet syndrome--aspects of diagnosis in the differential diagnosis of hand-arm vibration syndrome.

BACKGROUND: Thoracic outlet syndrome (TOS) is a cause of vascular and neurological compromise to the arm and hand, and may manifest as Raynaud's phenomenon. It may be under-diagnosed. AIM: This review was undertaken in order to clarify the diagnostic and investigative features of TOS that may differentiate it from hand-arm vibration syndrome. METHODS: A tiered review of the world literature was undertaken using Medline and Embase as the primary search engines. CONCLUSION: Thoracic outlet syndrome most commonly presents with neurological symptoms in the arm. Vascular symptoms, including Raynaud's phenomenon, may occur in approximately 10% of cases. Careful clinical assessment by history and examination may reveal the elements of forearm and upper arm symptoms with postural exacerbation, which distinguish this condition from hand-arm vibration syndrome. The usefulness of investigation is unclear, but Doppler and neuroelectric studies may be valuable. Magnetic resonance imaging scan is the investigation of choice.

Arm↗
PubMed2001

Hand-transmitted vibration and biodynamic response of the human hand-arm: a critical review.

Hand-arm vibration syndrome (HAVS) has been associated with prolonged exposure to vibration transmitted to the human hand-arm system from hand-held power tools, vibrating machines, or hand-held vibrating workpieces. The biodynamic response of the human hand and arm to hand transmitted vibration (HTV) forms an essential basis for effective evaluations of exposures, vibration-attenuation mechanisms, and potential injury mechanisms. The biodynamic response to HTV and its relationship to HAVS are critically reviewed and discussed to highlight the advances and the need for further research. In view of its strong dependence on the nature of HTV and the lack of general agreement on the characteristics of HTV, the reported studies are first reviewed to enhance an understanding of HTV and related issues. The characteristics of HTV and relevant unresolved issues are discussed on the basis of measured data, proposed standards, and measurement methods, while the need for further developments in measurement systems is emphasized. The studies on biodynamic response and their findings are grouped into four categories based on the methodology used and the objective. These include studies on (1) through-the-hand-arm response, expressed in terms of vibration transmissibility; (2) to-the-hand response, expressed in terms of the force-motion relationship of the hand-arm system; (3) to-the-hand biodynamic response function, expressed in terms of vibration energy absorption; and (4) computer modeling of the biodynamic response characteristics.

Arm↗
PubMed1997

[Tolerance limit of human upper extremity with arm restraint plate on eject seat to simulated aerodynamic loads].

To obtain tolerance limit of human upper extremity with arm restraint plate on eject seat to windblast, impact was applied to the upper extremity of 13 human corpses and 7 living monkeys by a spring driven impact device. Relationship between impact load, moment of elbow joints and arm injuries with arm restraint plate were studied. Relationship between biomechanical characteristic curve of human elbow joint and clinical injuries was obtained. The results indicated that tolerance limit of human upper arm is higher than forearm. Safety limit of human anterior arm to simulated aerodynamic load is 1.26 kN.

Aerospace Medicine↗
PubMed2004

Repetitive bilateral arm training and motor cortex activation in chronic stroke: a randomized controlled trial.

CONTEXT: Reorganization in central motor networks occurs during early recovery from hemiparetic stroke. In chronic stroke survivors, specific rehabilitation therapy can improve upper extremity function. OBJECTIVE: To test the hypothesis that in patients who have chronic motor impairment following stroke, specific rehabilitation therapy that improves arm function is associated with reorganization of cortical networks. DESIGN, SETTING, AND PATIENTS: A randomized controlled clinical trial conducted in a US ambulatory rehabilitation program with 21 patients (median [IQR], 50.3 [34.8-77.3] months after unilateral stroke). Data were collected between 2001 and 2004. INTERVENTIONS: Patients were randomly assigned to bilateral arm training with rhythmic auditory cueing (BATRAC) (n = 9) or standardized dose-matched therapeutic exercises (DMTE) (n = 12). Both were conducted for 1 hour, 3 times a week, for 6 weeks. MAIN OUTCOME MEASURES: Within 2 weeks before and after the intervention, brain activation during elbow movement assessed by functional magnetic resonance imaging (fMRI) and functional outcome assessed using arm function scores. RESULTS: Patients in the BATRAC group but not in the DMTE group increased hemispheric activation during paretic arm movement (P = .03). Changes in activation were observed in the contralesional cerebrum and ipsilesional cerebellum (P = .009). BATRAC was associated with significant increases in activation in precentral (P<.001) and postcentral gyri (P = .03) and the cerebellum (P<.001), although 3 BATRAC patients showed no fMRI changes. Considering all patients, there were no differences in functional outcome between groups. When only BATRAC patients with fMRI response were included (n = 6), BATRAC improved arm function more than DMTE did (P = .02). CONCLUSIONS: These preliminary findings suggest that BATRAC induces reorganization in contralesional motor networks and provide biological plausibility for repetitive bilateral training as a potential therapy for upper extremity rehabilitation in hemiparetic stroke.

Aged↗