Functional role of the corticoreticular pathway in chronic stroke patients.

BACKGROUND AND PURPOSE: The corticoreticular pathway (CRP) is known to be an important extrapyramidal tract for walking ability. However, little is known about the functional role of the CRP in recovery of walking ability. We investigated relation between the CRP and walking ability in chronic hemiparetic stroke patients. METHODS: Among 209 consecutive patients, 54 patients, who showed complete injury of the corticospinal tract (CST) in the affected hemisphere on diffusion tensor tractography, and 20 normal subjects were recruited. Functional ambulation category was used in measurement of walking ability. The fractional anisotropy value, apparent diffusion coefficient value, and fiber volume of the CRP and CST were used for the diffusion tensor imaging parameters. RESULTS: In the affected hemisphere, no significant difference in diffusion tensor imaging parameters of the CRP was observed between patient subgroups. In the unaffected hemisphere, patients who were able to walk showed significantly increased fiber volume of the CRP, compared with patients who could not walk and normal control subjects (P<0.05), without significant difference in fractional anisotropy and apparent diffusion coefficient values. In addition, the fiber volume of the CRP in the unaffected hemisphere showed positive correlation with functional ambulation category (P<0.05). In contrast, diffusion tensor imaging parameters of the CST in the unaffected hemisphere showed no correlation with functional ambulation category (P>0.05). CONCLUSIONS: The increased fiber volume of the CRP in the unaffected hemisphere seems to be related to walking ability in patients with chronic stroke. Therefore, the compensation of the CRP in the unaffected hemisphere seems to be one of the mechanisms for recovery of walking ability after stroke.

Inhibitory characteristics of flavonol-3-O-glycosides from Polygonum aviculare L. (common knotgrass) against porcine pancreatic lipase.

Pancreatic lipase (PL) is an enzyme that plays an essential role in the digestion of dietary lipids and is a suitable target for an anti-obesity dietary supplement. The objective of this study was to find a novel source of PL inhibitors from Korean medicinal plants and investigate the PL-inhibitory properties of the active constituents. From among 34 kinds of methanolic crude extracts, Polygonum aviculare L. showed the highest PL-inhibitory activity (63.97 ± 0.05% of inhibition). Solvent fractionation and liquid chromatography/mass spectrometry (LC/MS) analysis identified flavonol-3-O-glycosides, flavonol-3-O-(2″-galloyl)-glycosides, and flavonol aglycones as active constituents. Furthermore, the inhibitory characteristics of the major compounds were investigated in terms of enzyme kinetics and fluorescence quenching. The results suggested that the inhibitory activity of the major compounds is closely related to the tertiary structural change in PL, and that differences in inhibitory activity occurred due to slight discrepancies in their chemical structure.

Ipsi-lesional motor deficits in hemiparetic patients with stroke.

Previous studies have proven that motor deficits are expressed in the ipsi-lesional limbs of the injured hemisphere in a variety of motor tasks. However, it still remained controversial for the distinct characteristics of the motor deficits according to the dysfunction of each hemisphere related to motor control. We evaluated the performance of the ipsi-lesional limb in stroke patients and age-sex matched normal controls. Kinematic components such as the temporal variation and accuracy index were analyzed. Our findings revealed that both groups with right or left hemisphere damage showed poor accuracy in terms of complex visuomotor function. Overall, patients with left hemisphere damage exhibited temporal inconstancies in simple repetitive movement. Accordingly, the non-dominant hemisphere plays a primary role in the function of complex visuospatial accuracy, whereas the dominant hemisphere is mainly involved in the motor control of bilateral upper limbs as well as the performance of complex tasks. Therefore, we assumed that such deficits may be caused by damage of the lateralized hemispheric function, depending on the property of the performed task and hemispheric asymmetry. The manifest understanding of the ipsi-lesional motor abnormalities provides clinicians with useful neurophysiologic information, and with the necessity of careful evaluation and therapeutic intervention on the ipsi-lesional upper limb, often clinically assumed as "the non-affected side".

Plant virus cDNA chip hybridization for detection and differentiation of four cucurbit-infecting Tobamoviruses.

A plant virus cDNA chip was developed by using viral cDNA clones and microarray technology. The cDNA chip was designed for detection and differentiation of the four species of selected cucurbit-infecting tobamoviruses [target viruses: Cucumber green mottle mosaic virus (CGMMV); Cucumber fruit mottle mosaic virus (CFMMV); Kyuri green mottle mosaic virus (KGMMV); and Zucchini green mottle mosaic virus (ZGMMV)]. The chip consisted of cDNA clones of the four cucurbit-infecting tobamoviruses, two target-related tobamoviruses, and another three unrelated plant viruses. Polymerase chain reaction products were amplified from the selected cDNA clones and arrayed onto slide glass. The cDNA chip, which was called cucurbit-virus chip, detected successfully specific target viruses. When applied to probes made from ZGMMV-infected samples, ZGMMV reacted strongly with its homologous cDNA and moderately reacted with KGMMV and CFMMV, while it did not react with CGMMV on the same chip. CGMMV probe gave strong signal intensity to its homologous cDNA spot and weakly reacted with ZGMMV, KGMMV, and CFMMV. The signal intensity of all combinations of probe and target was correlated significantly with nucleotide sequence identities between the probes and target viruses based on scatter diagrams. The signals could be made as image files for specific virus detection, and this could be useful for virus identification and differentiation. This is the first report of plant virus detection by using cDNA chip technology.

Changes of plantar pressure distributions following open and closed kinetic chain exercise in patients with stroke.

OBJECTIVE: The aim of this study is to investigate whether progressive resistive training with closed-kinetic chain (CKC) and open-kinetic chain (OKC) exercises could change plantar pressure distribution during walking in patients with stroke. METHODS: Thirty-nine stroke patients were recruited and randomly divided into a CKC exercise group (n = 13), an OKC exercise group (n = 13), and a control group (n = 13). Both CKC and OKC exercise groups performed their own respective training programs 5 times per week for 6 weeks, whereas no training was done in the control group. Barefoot plantar pressure distribution was measured during walking in terms of contact area (CA), peak contact force (PCF), and contact impulse (CI) on each of three foot regions (i.e. forefoot (FF), midfoot (MF), and hindfoot (HF)). RESULTS: In the CKC exercise group, there were significant changes in only the CA and PCF of HF. In the OKC exercise and control groups, no significant differences were found for all variables of plantar pressure distributions. CONCLUSION: We found that resistive training with closed kinetic chain exercises could be an effective treatment method for improving normal gait patterns in stroke patients. These findings may be attributed to the fact that CKC exercise induced use of the ankle and knee muscles and provided repetitive sensory input from the affected foot.

The effect of transcranial direct current stimulation on the motor suppression in stop-signal task.

PURPOSE: This study examined whether transcranial direct current stimulation (tDCS) of the primary motor cortex alters the response time in motor suppression using the stop-signal task (SST). METHODS: Forty healthy subjects were enrolled in this study. The subjects were assigned randomly to either the tDCS condition or sham control condition. All subjects performed a stop-signal task in three consecutive phases: without, during or after the delivery of anodal tDCS on the primary motor cortex (the pre-tDCS motor phase, on-tDCS motor phase, and after-tDCS motor phase). RESULTS: The response times of the stopping process were significantly lower in each SST motor phase during or after tDCS (p < 0.05) and shorter immediately during delivery of the tDCS, whereas there was no change after the delivery of tDCS compared to sham condition. In contrast, the response times of the going process were similar under the two conditions (p > 0.05). No subjects complained of any adverse symptoms or signs. CONCLUSION: Anodal tDCS enhances voluntary going and stopping of movement in executive control. tDCS appears to be an effective modality to modulate motor suppression and its related dynamic behavioral changes in motor sequential learning.

Adverse effects of motor-related symptoms on the ipsilateral upper limb according to long-term cane usage.

OBJECTIVE: Although the cane is prescribed to aid in daily living and social participation in stroke patients, this study aimed to identify whether long-term cane usage affected sensorimotor functions in the distal part of the non-affected upper limb in relation to a tracking task, a nine-hole pegboard test, and proprioceptive joint sense. PATIENT AND METHOD: Forty stroke patients who were divided into a cane using group (CUG) or a non-cane using group (NCUG) participated in this study. Subjects were evaluated in a tracking task for visuomotor coordination, a nine-hole pegboard test for dexterous hand motion, and a joint reposition test for proprioceptive sense integrity. RESULT: Comparison of the CUG and NCUG revealed significant differences in performance of the tracking task, the nine-hole pegboard test, and the joint reposition test (p < 0.05). The CUG had more difficulty performing visuomotor coordination and dexterous hand motion tasks compared with the NCUG. Proprioceptive joint sense was also deteriorated in the CUG. CONCLUSION: These results suggest that stroke patients who use a cane for a long period, could experience decreased sensorimotor function in the ipsilateral upper limb of a damaged hemisphere. Therefore, it will be necessary to provide careful evaluation and appropriate therapeutic intervention for stroke patients who require the use of a cane over a long period.

Differences of ground reaction forces and kinematics of lower extremity according to landing height between flat and normal feet.

The study compared lower extremity kinematics and kinetics between male subjects with flat and normal feet when landing on both feet from platforms at different heights. Ten subjects with a flat feet arch and 10 subjects with a normal foot arch were recruited. They performed a double limb drop landing from 20, 40, and 60 cm onto a force-plate. A three-dimensional motion analysis system, force plates, and electromyography were used to analyze lower extremity kinetic and kinematic data. The GRF and angle of sagittal plane significantly increased with landing height in the flat foot group. In particular, hip joint angles at a height of 60 cm were significantly greater. The electromyography values were significantly higher for the tibialis anterior and vastus lateralis muscles, but were significantly lower in the abductor hallucis, gastrocnemius, and biceps femoris muscles in the flat foot group. GRF, joint angles, and muscle activity patterns in the lower extremities increases more with height in flat footed individuals than in people with a normal foot arch. Flat feet may aggravate the risk of shock on landing from a height; this might be ameliorated by a compensatory strategy at the hip joints to facilitate load distribution.

The effect of transcranial direct current stimulation on the cortical activation by motor task in the human brain: an fMRI study.

OBJECTIVES: We attempted to evaluate whether cortical activation resulting from hand movements is changed by transcranial direct current stimulation (tDCS) applied on the primary motor cortex for the hand in the human brain, using functional MRI (fMRI). METHODS: Fourteen normal subjects were recruited; subjects were randomly assigned to either the tDCS group (n=7) or the sham group (n=7). fMRI was performed with hand grasp-release movements at 1Hz before and after 20 min of intervention (the tDCS group: anodal tDCS, the sham group: sham stimulation). RESULTS: The activation of the tDCS underlying primary sensorimotor cortex (SM1) was significantly increased in the tDCS group (p<0.05). By contrast, the SM1 was significantly decreased in the sham group in terms of the voxel count and intensity (p<0.05). No subjects complained of any adverse symptoms or signs. CONCLUSION: We demonstrated that anodal tDCS increased the cortical excitability of the underlying motor cortex in the human brain. It seems that tDCS is an effective modality to modulate brain function.

Use of virtual reality to enhance balance and ambulation in chronic stroke: a double-blind, randomized controlled study.

OBJECTIVE: To examine an additive effect of virtual reality on balance and gait function in patients with chronic hemiparetic stroke. DESIGN: Twenty-four adults with hemiparetic stroke were randomly assigned to either an experimental group (n = 12) or a control group. Both groups underwent conventional physical therapy, 40 mins a day, 4 days a week for 4 wks. The experimental group received an additional 30 mins of virtual reality therapy each session. Balance performance was determined by the Balance Performance Monitor and Berg Balance Scale tests. Gait performance was determined by the 10-m walking test and Modified Motor Assessment Scale, and spatiotemporal parameters were obtained using GAITRite. Analysis of variance and correlation statistics were performed at P < 0.05. RESULTS: In the balance test, the experimental group had improved Berg Balance Scale scores, balance and dynamic balance angles (ability to control weight shifting) compared with the controls (P < 0.05). In the gait performance test, the experimental group showed significant improvements in velocity, Modified Motor Assessment Scale scores, cadence, step time, step length, and stride length (P < 0.05). Improvement in dynamic balance angles was correlated with velocity and cadence (P < 0.01). CONCLUSIONS: This study demonstrates that virtual reality has an augmented effect on balance and associated locomotor recovery in adults with hemiparetic stroke when added to conventional therapy.