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Biomedical subjects

R Dickstein

Publications and source records attributed to R Dickstein.

47 records · Page 3Linked to original sources

Platform training and postural stability in hemiplegia.

Thirteen hemiplegic patients who had a cerebrovascular accident (CVA) in the anterior cerebral circulation were subjected to training on a moving platform. Each session consisted of a 5 min stance on the platform while they moved along an anteroposterior axis, and a 5min stance during transverse movement. Movement amplitude of the platform was adjusted once every three training sessions to the largest that the patients could sustain without using their hands for support. An electromyogram (EMG) was recorded from the tibialis anterior (TA) muscles of each patient during training and at stance on the floor. In addition, the distribution of body weight on the feet was measured in each case before the training program began and at its termination after three weeks (15 training sessions). A matched group of 11 hemiplegic patients served as controls. The maximal movement amplitude that each patient in the control group could sustain was determined twice, once at the beginning of the study and again after three weeks. Ten patients in the experimental group showed more than a two-fold increase in the maximal movement amplitude (MMA) that they could sustain. The patients most impaired initially showed the greatest increase in MMA--five- to seven-fold. In the control group, only one patient had an MMA increase greater than two-fold. A significant improvement in weight distribution on the feet during stance on the floor was found in the experimental patients, but not in the controls. EMG records indicated that improvement in stance did not result from increased TA activation in the hindered leg.(ABSTRACT TRUNCATED AT 250 WORDS)

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The pneumatic post-amputation mobility aid in geriatric rehabilitation.

Several disadvantages of rigid temporary dressings for geriatric amputees led to the trial of a relatively new kind of pylon--the Pneumatic Post-Amputation Mobility Aid (PPAM). Thirty-five geriatric amputees who were referred to a geriatric rehabilitation hospital participated in the study. Thirty-three of these patients learned to walk with the device easily and safety. The below-knee amputees achieved independent gait with a walker as early as their second treatment. The above-knee and the double below-knee amputees required closer supervision. The inexpensive price of the PPAM, its handiness, the possibility of treating several patients with the same device, and the lack of negative side effects, point to the advantages of this kind of pylon for geriatric patients.

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Detection of ligand-induced perturbations affecting the biotinyl group of mammalian acetyl-coenzyme A carboxylase by using biotin-binding antibodies.

Biotin-binding antibodies were raised in rabbits by injecting biotin-bovine serum albumin conjugate. Neither the protomer nor the polymer of rat mammary-gland acetyl-CoA carboxylase formed precipitin bands with the anti-biotin. By virtue of its ability to bind biotin (apparent binding constant for free biotin about 1mum), the anti-biotin inhibited the carboxylase activity under certain conditions. This property of the antibody was employed to detect the ligand-induced changes affecting the biotinyl group in different conformational states of mammalian carboxylase. Depending on the ligand present, the biotinyl group in the protomeric form was either accessible or inaccessible to the antibody. The biotinyl group of the protomer generated by a relatively high concentration of NaCl (0.5m) reacted with the antibody, and the antibody-carboxylase complex could not be converted into active enzyme by citrate. Further experiments showed that citrate failed to induce polymerization in this protomer-antibody complex and that anti-biotin could be displaced rapidly from this complex with excess of biotin. The resulting protomer was converted into the polymeric state on citrate addition, with parallel regain of enzyme activity. In the presence of ADP+Mg(2+), ATP+Mg(2+) or ATP+Mg(2+)+HCO(3) (-), however, the enzyme remained as a protomer, but its configuration was such that the biotinyl group was essentially inaccessible to the antibody. Likewise, the biotinyl group of the different polymeric forms of the carboxylase (s approximately 30-45S) engendered by phosphate, malonyl-CoA, acetyl-CoA or citrate remained essentially inaccessible, since their activity was minimally affected by the anti-biotin. In the presence of 0.15m-NaCl, the phosphate-induced polymer reverted to a approximately 19S form with concomitant appearance of anti-biotin-sensitivity, whereas the other polymeric forms remained unaffected under similar experimental conditions.

Acetyl-CoA Carboxylase↗

ENOD8, a novel early nodule-specific gene, is expressed in empty alfalfa nodules.

The alfalfa ENOD8 nodule-specific gene is expressed in empty nodules elicited by exopolysaccharide-deficient Rhizobium meliloti, and it is expressed early in nodule development. An ENOD8 cDNA was sequenced and found to encode a novel product. Its deduced polypeptide sequence was found to be similar to the nonproline-rich domains of the putative polypeptides encoded by a class of anther-specific genes from Arabidopsis thaliana and Brassica napus. The role of the ENOD8 gene product is predicted to be in nodule organogenesis. ENOD8 is expressed in a developmental pathway triggered as a result of Rhizobium nodulation signal transduction.

Amino Acid Sequence↗

Electromyographic activity of the biceps brachii muscles and elbow flexion during associated reactions in hemiparetic patients.

Activity of the biceps brachii muscles and movements of the elbows were studied during associated reactions in hemiparetic patients and in healthy volunteers. Onset time and increase in electromyographic (EMG) activity during associated reactions and onset of elbow flexion and its maximal magnitude were measured. Testing was performed while standing with a footswitch attached to the sole of the nonparetic foot in patients and to the sole of the right foot in controls. Lifting of that foot generated a trigger signal that served to time the dependent variables. Bilateral EMG activity associated with one foot stance appeared in the two upper extremities in both patients and controls. Elbow flexion occurred in the majority of patients bilaterally, whereas in controls it frequently took place on one side only. There was a significant difference between patients and controls in onset of EMG activity and elbow flexion. This difference indicates an earlier preparatory activity to one foot stance in the upper limbs of patients than in healthy controls. The greatest excursion into flexion was measured in the paretic upper extremity of patients; it significantly exceeded both the flexion angle measured in controls and increase in flexion angle on the nonparetic side. Further understanding of the nature of associated reactions seems to be required for their adequate treatment by physical procedures.

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Activation of flexor and extensor trunk muscles in hemiparesis.

OBJECTIVE: The purpose of this work was to study the bilateral activity of trunk flexor and extensor muscles in post-stroke hemiparetic patients. DESIGN: Criterion variables were degree of temporal synchronization and level of electromyographic activity in pertinent muscle pairs during two symmetrical tasks: (1) from reclined sitting, bringing the trunk forward; (2) during upright sitting, shrugging shoulders, and extending back. The recti abdomini and external oblique muscles were tested as prime movers of the first task, and the lumbar erector spinae and latissimus dorsi muscles were tested in the second task. Electromyographic recordings from these muscles during three repetitions of each exercise were used for analysis. RESULTS: Cross-correlation analysis pointed to higher temporal synchronization between the abdominal muscles than between the back extensor muscles and in axial compared with para-axial muscles. Differences between patients and controls were found only for the erector spinae muscle pair, which indicates less synchronous activity between the two sides in the patients. The average electromyographic activity level was comparable for corresponding abdominal muscles, both in the patients and in the control subjects. Regarding the back extensor, side differences were detected for the latissimus dorsi muscles in both groups, with the paretic and right side less active in the patients and controls, respectively. CONCLUSIONS: Altogether, the findings do not support the claim of unilateral deficits in the function of trunk muscles in post-stroke hemiparetic patients. They emphasize the need for further characterization of the impairment of trunk extensor and flexor muscles in post-stroke patients.

Abdominal Muscles↗

Physical rehabilitation of the elderly blind patient.

OBJECTIVE: to evaluate the policy of admitting elderly blind patients with motor impairments for physical rehabilitation. DESIGN: retrospective chart review for comparisons between blind and visually intact patients with similar diagnoses. SETTING: geriatric rehabilitation hospital. PATIENTS: all patients with stroke, fractured hip, and lower limb amputation. EXCLUSIONS: none. ASSESSMENTS: walking ability and functional performance (ADL), using the Barthel Index. RESULTS: overall outcome in blind patients was only slightly less favourable than in the visually intact, although, in comparison with premorbid status, only just over half were ambulatory at discharge and functional independence was less common. CONCLUSIONS: elderly blind patients with motor impairments should be offered a trial by physical rehabilitation.

Activities of Daily Living↗

Evaluating the effects of reflex-inhibiting patterns among hemiplegic patients using EMG biofeedback.

Bobath's hypothesis--that the reflex-inhibiting patterns (RIP)s of a hemiplegic patient's non-exercising limb will prevent an abnormal increase in the muscle tone while the ipsilateral limb is being exercised--is examined in this study with the aid of an EMG biofeedback unit. Recordings were taken of the biceps brachii muscle of 15 patients during performance of lower extremity exercise, and from the medial gastrocnemius muscle of 12 patients during performance of an upper extremity exercise. Each muscle was examined six times in the same session: three of these repetitions being conducted in a RIP, the other three in a neutral position. The highest EMG values recorded in each of the two test situations were compared. The results did not point to a definite relationship between the RIPs and the electrical activity of the test muscles. Bobath's claim that there exists a consistent trend relating RIPs to reduction of muscle tone is therefore placed in doubt. Further research using objective techniques is required as a means of exploring this issue.

Electromyography↗

The effect of treadmill training on the ambulation of stroke survivors in the early stages of rehabilitation: a randomized study.

The objective of this study was to compare the effects of conventional over-ground gait training with treadmill training on the restoration of gait in people with hemiparesis following a stroke. Twenty-five individuals in the early stages of rehabilitation were alternately assigned to one of two treatment groups. In addition to conventional physical therapy, the experimental group participated in 15 treadmill-training sessions in which a handrail was used for external support. The control group received the same number of equal length sessions of over-ground ambulation. Treatment effects were established by pre- and posttreatment assessment of: 1) functional walking ability, 2) walking speed, 3) stride length, 4) temporal characteristics of gait, and 5) electromyographic activity of calf muscles. Normal values were obtained from eight healthy individuals of approximately the same age as the stroke survivors. The study demonstrates that individuals following a stroke are well able to tolerate treadmill training in the early stage of their rehabilitation process without the use of a weight support apparatus. Furthermore, the findings suggest that treadmill training may be more effective than conventional gait training for improving some gait parameters such as functional ambulation, stride length, percentage of paretic single stance period, and gastrocnemius muscular activity.

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