Biomedical subjects

Yea-Ru Yang

Publications and source records attributed to Yea-Ru Yang.

14 recordsLinked to original sources

PubMed2006

Influence of external and intracellular pH on propofol-induced responses in rat locus coeruleus neurons.

The effect of external and intracellular pH on propofol-induced responses in rat locus coeruleus neurons was examined using intracellular recording from in vitro brain slice preparations. Experimental variation of external pH from 7.34 to 6.81 did not affect the propofol-induced responses. In contrast, raising the external pH from 7.34 to 8.10 resulted in enhanced 100 microM propofol effects. The effects were 1.8 times greater on membrane hyperpolarization (pH 8.10: 11.8 +/- 1.3 mV; pH 7.34: 6.5 +/- 1.0 mV, n = 5) and 1.5 times greater on reduction in input resistance (pH 8.10: 38.2 +/- 6.3%; pH 7.34: 24.7 +/- 4.1%, n = 5). Cytosolic acidification was used in which 1/3 NaCl in artificial cerebrospinal fluid was replaced with weak organic acids--sodium acetate. It did not significantly affect the propofol-induced responses. On the other hand, intracellular alkalinization with 5 mM NH(4)Cl markedly suppressed the 100 microM propofol-induced membrane hyperpolarization (1.0 +/- 0.6 mV; control: 13.9 +/- 0.9 mV, n = 5) and reduction of input resistance (38.1 +/- 1.3%; control: 61.0 +/- 4.3%, n = 5). However, the presence of 3-5 mM ammonium acetate also showed the similarly suppressing effect on membrane hyperpolarization (1.7 +/- 0.6 mV; control: 9.2 +/- 1.8 mV, n = 5) and reduction of input resistance (28.5 +/- 8.5%; control: 37.0 +/- 6.3%, n = 5) caused by 100 microM propofol. We suggested that the main suppressing effect of NH(4)Cl results from ammonium ion, but not intracellular alkalinization. Furthermore, we examined the feature of pharmacological regulation of propofol-induced responses by pentobarbital or alphaxalone during pH changes. It appears that neither pentobarbital nor alphaxalone could allosterically modulate the propofol-induced responses, which had been affected by pH changes.

Acidosis↗

PubMed2006

Dual-task-related gait changes in individuals with stroke.

Many daily activities require people to complete a motor task while walking. The purpose of this study was to analyze subjects' ability to perform motor tasks while walking. Subjects were classified into three different groups. The first group included 15 full community ambulators post-stroke. The second group included 15 least limited community ambulators post-stroke. The final group included 15 age-matched healthy subjects. Gait performance was measured under three different conditions: (1) preferred walking (single task); (2) walking buttoning up (buttoning task); (3) walking while carrying a tray with glasses (tray-carrying task). Gait velocity, cadence, stride time, stride length, temporal and spatial symmetry indices were examined with the GAITRite system. Our results showed that there were no significant differences between full community ambulators and control subjects for all gait variables. However, there were significant differences in dual-task-related gait decrement between the full community ambulators and control subjects. There were also significant differences in dual-task-related gait decrement between least limited community ambulators and control subjects. The findings of this study suggest that subjects with stroke including the full community ambulators have difficulty performing two motor tasks concurrently.

Adult↗

PubMed2006

The relation between ankle impairments and gait velocity and symmetry in people with stroke.

OBJECTIVE: To identify the most important factor among the ankle impairments on gait velocity and symmetry in stroke patients. DESIGN: Cross-sectional, descriptive analysis of convenience sample. SETTING: Patients from outpatient rehabilitation and neurovascular neurology departments in medical centers and municipal hospitals in Taiwan. PARTICIPANTS: Sixty-eight subjects with hemiparesis poststroke with the ability to walk independently. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Maximal isometric strength of plantarflexors and dorsiflexors were examined by a handheld dynamometer. Spasticity index, slope magnitudes between electromyographic activities, and muscle lengthening velocity of gastrocnemius during lengthening period of stance phases were measured to represent the dynamic spasticity. Passive stiffness of pantarflexors was indicated by degrees of dorsiflexion range that were less than normative values. Position error was measured by the degree of proprioceptive deficits of ankle joint by evaluating the joint position sense. Gait velocity, symmetry, and other gait parameters were measured by the GAITRite system. RESULTS: Regression analyses revealed that the dorsiflexors strength was the most important factor for gait velocity and temporal symmetry (R(2)=.30 for gait velocity, P<.001; R(2)=.36 for temporal asymmetry, P<.001). Dynamic spasticity was the most important determinant for gait spatial symmetry (R(2)=.53, P<.001). CONCLUSIONS: Gait velocity and temporal asymmetry are mainly affected by the dorsiflexors strength, whereas dynamic spasticity of plantarflexors influenced the degree of spatial gait asymmetry in our patients who were able to walk outdoors. Treatment aiming to improve different aspects of gait performance should emphasize on different ankle impairments.

Ankle↗

PubMed2006

Balance ability in patients with benign paroxysmal positional vertigo.

OBJECTIVE: The purpose of the study was to investigate the balance ability of the patients with benign paroxysmal positional vertigo (BPPV). STUDY DESIGN AND SETTING: Twenty-three patients (63.3 +/- 9.2 years of age) with a diagnosis of unilateral posterior semicircular canal BPPV were recruited. Static balance was measured in 4 conditions with eyes open and eyes closed: stance on firm surface, stance on foam surface, left leg stance, and right leg stance. Dynamic balance was measured in tandem walk test. Data of the patients with BPPV were compared to age-matched norm values of the healthy adults. RESULTS: The patients with BPPV demonstrated greater sway velocity in stance on foam surface with eyes closed (P < 0.05), in single leg stance with eyes closed (P < 0.001), and in tandem walk test (P < 0.05) compared to the healthy adults. CONCLUSIONS: Patients with BPPV demonstrated impaired static and dynamic balance ability particularly when depriving visual and changing proprioceptive inputs. SIGNIFICANCE: Clinically, in addition to canalith repositioning maneuver, balance retraining on different conditions may be a useful adjunct to treatment for patients with BPPV.

Aged↗

PubMed2006

Task-oriented progressive resistance strength training improves muscle strength and functional performance in individuals with stroke.

OBJECTIVE: To examine the effectiveness of task-oriented progressive resistance strength training on lower extremity strength and functional performance in chronic stroke subjects. DESIGN: Single-blind, randomized controlled trial. SETTING: Medical centre and district hospital. SUBJECTS: Forty-eight subjects at least one year post stroke. INTERVENTIONS: Participants randomly allocated to two groups, control (n-/24) and experimental (n-/24). Subjects in the control group did not receive any rehabilitation training. Subjects in the experimental group were put on a four-week task-oriented progressive resistance strength training. MAIN MEASURES: Lower extremity muscle strength, gait velocity, cadence, stride length, six-minute walk test, step test, and timed up and go test. RESULTS: Muscle strength significantly improved in the experimental group for strong side muscle groups (ranged from 23.9% to 36.5%) and paretic side muscle groups (ranged from 10.1% to 77.9%). In the control group muscle strength changes ranged from 6.7% gain to 11.2% decline. The experimental group showed significant improvement in all selected measures of functional performance except for the step test. In the control group, the number of repetitions of the step test significantly decreased (-20.3%) with no change in other functional tests. There was a significant difference between groups for muscle strength and all functional measures. The strength gain was significantly associated with gain in the functional tests. CONCLUSIONS: The task-oriented progressive resistance strength training programme could improve lower extremity muscle strength in individuals with chronic stroke and could carry over into improvement in functional abilities.

Aged↗

PubMed2005

Ankle muscle activation during functional reach in hemiparetic and healthy subjects.

OBJECTIVE: To compare the differences of reaching ability and electromyography of ankle muscles between healthy and hemiparetic subjects. DESIGN: This is a cross-sectional control trial. A total of 31 subjects with hemiparesis and 31 age-matched healthy adults meeting our selection criteria participated in this study. Subjects performed forward reach and lateral reach, in random sequence, in a sitting position. The average reaching velocity, reaching distance, and onset time and mean muscle activity of bilateral tibialis anterior and soleus were recorded. RESULTS: Subjects with hemiparesis had slower movement velocity and less reaching distance than that of healthy subjects (P < 0.05). The distance for the lateral reach was shorter than that of the forward reach (P < 0.05). The high correlations between contralateral tibialis anterior and soleus were noted in forward (r = 0.66, P < 0.01) and lateral (r = 0.68, P < 0.01) reaching in healthy subjects, but such correlations were not established in subjects with hemiparesis. Except for the ipsilateral soleus, normalized electromyographic activities (percentage of maximal voluntary isometric contraction) during forward and lateral reach were higher for the hemiparetic subjects than that for the healthy subjects (P < 0.05). CONCLUSION: The functional reach abilities and the ankle electromyographic activity patterns in hemiparetic subjects were significantly different from those of healthy subjects. The muscles in the affected ankle cannot be recruited timely and efficiently for the reaching task, even with relative recovery.

Ankle↗

PubMed2005

Effects of an ankle-foot orthosis on balance performance in patients with hemiparesis of different durations.

OBJECTIVE: To examine the effects of an ankle-foot orthosis (AFO) on balance performance in patients with hemiparesis of short and long duration. DESIGN: Within-subject random order of intervention, cross-sectional study design. SETTINGS: Medical centres and district hospitals. SUBJECTS: Forty-two subjects with hemiparesis of short duration (< six months) and 61 subjects of long duration ( > 12 months). MEASUREMENTS: The balance and gait ability of subjects were evaluated both with an AFO and without. The static and dynamic balance activities were evaluated by the Balance Master System, whereas the functional balance was assessed with the Berg Balance Scale. The speed and cadence were also measured during a 10-metre walk. Paired t-test was used to determine the effect of the AFO. RESULTS: In subjects with hemiparesis of short duration, we found that subjects wearing an AFO showed significant improvements in (1) weight-bearing distribution during quiet standing (p = 0.042, 95% confidence interval (CI) 0.521, 7.325), (2) body sway during standing on foam surface with eyes open (p = 0.020, 95% CI 0.020, 0.680) and eyes closed (p = 0.041, 95% CI 0.023, 0.921), (3) movement velocity during limit of stability test (LOS)--toward the affected side (p = 0.037, 95% CI - 0.978, - 0.042) and nonaffected side (p = 0.008, 95% CI -2.223, - 0.377), (4) maximal excursion toward the affected side (p= 0.042, 95% CI -19.546, -0.071), and (5) speed (p=0.028, 95% CI -0.204, -0.017) and cadence (p= 0.021, 95% CI - 22.983, - 1.864). Such effects were not observed in subjects with hemiparesis of long duration. CONCLUSIONS: For the subjects with hemiparesis of short duration, the AFO improves the symmetry in quiet and dynamic standing balances. It also increases speed and cadence. However, its effectiveness is minimal for patients of long duration.

Ankle↗

PubMed2005

Efficacy of Bobath versus orthopaedic approach on impairment and function at different motor recovery stages after stroke: a randomized controlled study.

OBJECTIVE: To investigate the effectiveness of Bobath on stroke patients at different motor stages by comparing their treatment with orthopaedic treatment. DESIGN: A single-blind study, with random assignment to Bobath or orthopaedic group. SETTING: Physical therapy department of a medical centre. SUBJECTS: Twenty-one patients with stroke with spasticity and 23 patients with stroke at relative recovery stages participated. INTERVENTIONS: Twenty sessions of Bobath programme or orthopaedic treatment programme given in four weeks. MAIN OUTCOME MEASURES: Stroke Impairment Assessment Set (SIAS), Motor Assessment Scale (MAS), Berg Balance Scale (BBS) and Stroke Impact Scale (SIS) for impairment and functional limitation level. RESULTS: Participants with spasticity showed greater improvement in tone control (change score: 1.20 +/- 1.03 versus 0.08 +/- 0.67, p = 0.006), MAS (change score: 7.64 +/- 4.03 versus 4.00 +/- 1.95, p = 0.011), and SIS (change score: 7.30 +/- 6.24 versus 1.25 +/- 5.33, p = 0.023) after 20 sessions of Bobath treatment than with orthopaedic treatment. Participants with relative recovery receiving Bobath treatment showed greater improvement in MAS (change score: 6.14 +/- 5.55 versus 2.77 +/- 9.89, p = 0.007), BBS (change score: 19.18 +/- 15.94 versus 6.85 +/- 5.23, p = 0.015), and SIS scores (change score: 8.50 +/- 3.41 versus 3.62 +/- 4.07, p = 0.006) than those with orthopaedic treatment. CONCLUSION: Bobath or orthopaedic treatment paired with spontaneous recovery resulted in improvements in impairment and functional levels for patient with stroke. Patients benefit more from the Bobath treatment in MAS and SIS scores than from the orthopaedic treatment programme regardless of their motor recovery stages.

Exercise Therapy↗

PubMed2005

Gait outcomes after additional backward walking training in patients with stroke: a randomized controlled trial.

OBJECTIVE: To examine the effectiveness of additional backward walking training on gait outcome of patients post stroke. DESIGN: Randomized controlled trial. SETTING: Medical centre. SUBJECTS: Twenty-five subjects with stroke, who were lower extremity Brunnstrom motor recovery stage at 3 or 4 and were able to walk 11 m with or without a walking aid or orthosis, randomly allocated to two groups, control (n = 12) and experimental (n = 13). INTERVENTIONS: Subjects in both groups participated in 40 min of conventional training programme three times a week for three weeks. Subjects in experimental group received additional 30 min of backward walking training for three weeks at a frequency of three times per week. MAIN MEASURES: Gait was measured using the Stride Analyzer. Gait parameters of interest were walking speed, cadence, stride length, gait cycle and symmetry index. Measures were made at baseline before commencement of training (pre-training) and at the end of the three-week training period (post-training). RESULTS: After a three-week training period, subjects in experimental group showed more improvement than those in control group for walking speed (change score: 8.60 +/- 6.95 versus 3.65 +/- 2.92, p-value = 0.032), stride length (change score: 0.090 +/- 0.076 versus -0.0064 +/- 0.078, p-value = 0.006), and symmetry index (change score: 44.07 +/- 53.29 versus 5.30 +/- 13.91, p-value = 0.018). CONCLUSIONS: This study demonstrated that asymmetric gait pattern in patients post stroke could be improved from receiving additional backward walking therapy.

Female↗

PubMed2003

Early and late treadmill training after focal brain ischemia in rats.

Treadmill training is increasingly recognized as an effective means to promote rhythmical vigorous walking and also as a useful method of task-related training. The present study endeavored to investigate the effects of early and late treadmill training after ligation of the middle cerebral artery. Forty male Sprague-Dawley rats were subjected to 60 min right middle cerebral artery occlusion (MCAO). All rats were randomly assigned to one of four groups: 24 h group, 2 week no training group, early training group (training started 24 h post MCAO), and late training group (training started 1 week post MCAO). Infarct volume was measured morphometrically. A five-point neurological evaluation scale was used to assess the neurological status of rats. Rats sacrificed 24 h post MCAO had the largest infarct volume (177.8+/-14.3 mm(3)) and the highest neurological score [2(1-4)]. Early treadmill training was found to have significant effects in reducing brain infarct volume and in improving neurologic function when compared with spontaneous recovery. However, the same effects cannot be found in late training. Based on the present findings, we would encourage early treadmill training for ischemic brain recovery.

Animals↗

PubMed2003

Treadmill training effects on neurological outcome after middle cerebral artery occlusion in rats.

BACKGROUND: Treadmill training is used for promoting rhythmical vigorous walking and for task-related training in patients with stroke. The neurological impact of treadmill training has not been established. The present investigation is aimed at (1) examining neurological changes over a four-week period after middle cerebral artery occlusion (MCAO) in rats and (2) assessing the impact of one-week, two-week and four-week treadmill training in MCAO rats. METHODS: Male Sprague-Dawley rats were subjected to 60-minute right MCAO. All rats were randomly assigned to one of seven groups. Infarct volume and neurological score were measured. RESULTS: Rats sacrificed 24 hours post MCAO had the largest infarct volumes (171.4 +/- 14.4 mm3) and the highest neurological score (median: 2, range: 1-3). We noted that without treadmill training, infarct sizes and neurological score diminished with time. Treadmill training for at least one week further reduced infarct volume and significantly improved neurologic function in MCAO rats. CONCLUSION: Treadmill training after focal cerebral ischemia significantly improves neurological outcome in MCAO rats. Treadmill training may be beneficial for ischemic brain recovery.

Animals↗

PubMed2002

Effects of functional electric stimulation on upper limb motor function and shoulder range of motion in hemiplegic patients.

OBJECTIVES: The present study examines functional electric stimulation (FES) applied on patients with hemiplegia of short and long duration for the purpose of upper limb motor recovery and increasing shoulder range of motion. DESIGN: Patients with hemiplegia with subluxation participating in the study were placed into a short-duration group or a long-duration group. Subjects in each group were then randomly assigned to either the control or the experimental subgroup. The experimental groups of both short- and long-duration groups received FES therapy in which the supraspinatus and posterior deltoid muscles were induced to contract repetitively up to 6 hr a day for 6 wk. Duration of FES session and muscle contraction/relaxation ratio were progressively increased as performance improved. The experimental groups also received a second 6-wk FES therapy 6 wk after completing the first FES therapy. RESULTS: After the first 6-wk FES therapy, the experimental group of short-duration hemiplegia showed significant improvements in motor recovery as indicated by Fugl-Meyer scores compared with the control group. Such significant improvement did not occur for the experimental group of long-duration hemiplegia. The changes in the second FES treatment program were insignificant. CONCLUSIONS: This study suggests that patients with hemiplegia of short duration are effectively trained by FES for motor recovery.

Adult↗

PubMedDate not supplied

Effect of age in rats following middle cerebral artery occlusion.

BACKGROUND: Despite the impressive increased understanding of the ischemic brain damage in general, the study of effects on different age groups, young versus old, using comparable ischemic insults is clearly lacking. OBJECTIVES: To investigate the mortality rate and neurological outcome among young and old rats, through a model of cerebral ischemia by middle cerebral artery occlusion (MCAO). METHODS: Twenty-three old (22-24 months of age) and 16 young (3-4 months of age) male rats underwent a MCAO procedure for 60 min. Surviving rats were randomly assigned to the 24-hour or 28-day resting group. The mortality rate and neurological outcome in different recovery time periods were determined for comparison between the young and old rats. RESULTS: The overall mortality rate in old rats (43.5%) was significantly higher than that of the young rats (6.3%) (p = 0.01). The infarct volume for the 24-hour post-MCAO was 181.86 +/- 11.87 mm(3) for the young rats, and 204.64 +/- 27.18 mm(3) for the old rats. For the 28-day post-MCAO, the value was 91.16 +/- 3.59 mm(3) for the young rats, and 103.38 +/- 26.43 mm(3) for the old rats. A significant reduction in infarct volume is noted in both young (p < 0.01) and old (p < 0.05) rats after 28 days of recovery compared to that after 24 h of recovery. There was no meaningful difference in infarct volume between the young and old rats measured at 24 h or 28 days after the ischemic procedure. The right volume was larger than the left volume at 24 h post-MCAO for both the young and the old rats, whereas the quotient approached unity for the young rats at 28 days post-MCAO. For the old rats, the quotient was negative at 28 days post-MCAO, representing the ipsilateral hemisphere was smaller than the contralateral hemisphere. CONCLUSION: The mortality risk to ischemic damage is greater for old rats. If an old rat survives the high-risk mortality in a short period after the MCAO procedure, the recovery would be of no difference to that of a young rat.

Aging↗

PubMedDate not supplied

Treadmill training effects in different age groups following middle cerebral artery occlusion in rats.

BACKGROUND: Despite the increased understanding of treadmill training on stroke patients, its effects on different age groups are not clearly known. The present study presents such effects through a model of cerebral ischemia on young and old groups of rats. OBJECTIVES: To investigate the effect of treadmill training on young and old rats after cerebral ischemia caused by middle cerebral artery occlusion (MCAO). METHODS: Forty old (22-24 months of age) and 32 young (3-4 months of age) rats underwent the MCAO procedure for 60 min. Rats that survived the procedure were randomly assigned to a 1- or a 2-week treadmill training group, or a time-matched control group (n=6-8 for each group). The infarct volume was compared between the treadmill training and the control groups for both the young and old rats at 1 or 2 weeks. RESULTS: After treadmill training for 1 week, the mean infarct volume was 7.26+/-0.49 and 9.51+/-0.84% for the young and old rats, respectively. The 1-week treadmill training effect was significant in the young rats (p=0.0207) but not in the old rats (p=0.0840). The mean infarct volume was 6.84+/-0.51 and 7.63+/-0.52% for the young and old rats, respectively, after the 2-week treadmill training. Both the young and old rat groups demonstrated a significant reduction in the infarct volume compared with that of the control group (p=0.021 for the young group and p=0.039 for the old group) after 2 weeks of treadmill training. CONCLUSION: The present findings clearly demonstrate the different training effects of locomotor activity in reducing ischemic infarction in young and old rats. The delayed reduction in ischemic infarction in old rats was notable and may be attributable to the slow response of angiogenic and neurogenic mechanisms in the old rats.

Age Factors↗