Neural Mechanism Underlying Task-Specific Enhancement of Motor Learning by Concurrent Transcranial Direct Current Stimulation.

The optimal protocol for neuromodulation by transcranial direct current stimulation (tDCS) remains unclear. Using the rotarod paradigm, we found that mouse motor learning was enhanced by anodal tDCS (3.2 mA/cm2) during but not before or after the performance of a task. Dual-task experiments showed that motor learning enhancement was specific to the task accompanied by anodal tDCS. Studies using a mouse model of stroke induced by middle cerebral artery occlusion showed that concurrent anodal tDCS restored motor learning capability in a task-specific manner. Transcranial in vivo Ca2+ imaging further showed that anodal tDCS elevated and cathodal tDCS suppressed neuronal activity in the primary motor cortex (M1). Anodal tDCS specifically promoted the activity of task-related M1 neurons during task performance, suggesting that elevated Hebbian synaptic potentiation in task-activated circuits accounts for the motor learning enhancement. Thus, application of tDCS concurrent with the targeted behavioral dysfunction could be an effective approach to treating brain disorders.

Expression of HGF/c-Met is dynamically regulated in the dorsal root ganglions and spinal cord of adult rats following sciatic nerve ligation.

Hepatocyte growth factor (HGF) and its receptor c-Met play pivotal roles in post-traumatic regeneration of the nervous system. However, following peripheral nerve injury, the role and regulation of the HGF/c-Met system is less clear. Therefore, using a sciatic nerve ligation (SNL) model, spatiotemporal changes in HGF and c-Met expression were detected in the dorsal root ganglions (DRGs) and lumbar spinal cords of adult rats. HGF expression following SNL was found to be significantly decreased in ipsilateral L4-L5 DRGs from day 3 to day 14, with the lowest levels of expression detected on days 5 and 7. In contrast, no significant change in HGF expression was detected in the lumbar spinal cords. c-Met expression in ipsilateral L4-L5 DRGs and within the ipsilateral dorsal horn was found to be significantly up-regulated following SNL, particularly from day 5 to day 14, with peak levels of expression detected on days 7 and 14. In contrast, c-Met levels following SNL consistently remained stable in the spinal ventral horn. These findings suggest that the HGF/c-Met system is spatiotemporally regulated by a unique pattern of signaling pathways induced by peripheral nerve injury, and these pathways have a role in promoting the survival of injured neurons, especially adult DRG sensory neurons.

[Optimization of antibiotics in combination].

OBJECTIVE: To evaluate the antibacterial activity of Ciprofloxacin, Amikacin in combination with beta-lactams against Pseudomonas aeruginosa strains in vitro, to optimize treatment regime for antibiotics on the basis of pharmacokinetics (PK)/pharmacodynamics (PD) and drug sensitivity tests. Methods With checkerboard titration method, the minimal inhibitory concentrations (MIC) of a combination of antibiotics in different concentrations for 33 clinically isolated Pseudomonas aeruginosa strains were determined by broth dilution. Fractional inhibitory concentrations (FIC) were calculated for judging synergic effect of antibiotics. RESULTS: The combination of Amikacin and Ceftazidime showed synergic effects (accounting for 57.6%). The combinations of Ciprofloxacin with Ceftazidime, Cefepime, Imipenem/Cilastatin, Meropenem showed synergic or additive effect. In the study with PK/PD, C(max)/MIC was the principal parameters for evaluation of aminoglycoside and fluoroquinolone antibiotics, while T > MIC was the principal parameter to be used to evaluate beta-lactams antibiotics. CONCLUSION: When antibiotics are used in combination, MICs can be reduced significantly and antibacterial activities are enhanced remarkably. The combination of antibiotics results mainly in synergic or additive effect, and no inhibitory effect is observed. PK/PD analysis plays an important role in planning optimal combination regime to raise clinical efficacy.

[Applied anatomy of inferior epigastric artery in coronary artery bypass grafting].

OBJECTIVE: To measure the inferior epigastric artery(IEA),coronary artery and arterial bridge to supply the anatomic and hemodynamic data of IEA in coronary artery bypass grafting for clinicians. METHODS: Anatomic method was adopted to measure the length of IEA, arterial bridge, the outer diameter of IEA and coronary arteries. Colour doppler ultrasound instrument was adopted to measure the caliber and the blood flow rate of IEA and coronary artery. RESULTS: In the anatomic method, the length of IEA was (13.00+/-2.58)cm and the caliber of original IEA was (2.95+/-0.21)mm, the caliber of IEA intersecting with abdomen rectus was (2.51+/-0.32)mm, and (1.60+/-0.26)mm at 1.0 cm below the umbilicus. In color doppler ultrasound method, the caliber of original IEA was (2.98+/-0.37)mm, and at 5 cm from the original spot was (2.60+/-0.27)mm. The blood flow rate was (57.00+/-6.78)cm/s. The main stem caliber of the left coronary artery was (4.90+/-0.76)mm, and that of the right coronary artery was (3.58+/-0.63)mm; the blood flow rate was (48.50+/-7.72)cm/s. The length of the arterial bridge was (10.95+/-1.35) approximately (15.30+/-2.82)cm. CONCLUSION: IEA can bridge the aorta and the coronary artery branches including the left anterior descending branch, the left circumflex branch and the right main coronary artery in free grafting. Its caliber and blood flow rate can match with those of the coronary artery. Before the operation of applying color doppler ultrasound instrument, the safety of IEA in the coronary artery bypass grafting can be evaluated to provide a new safe method in clinical follow-up.

[Microscopic study on skin and soft tissue after repeated expansion].

OBJECTIVE: The study was to evaluate the microscopic changes on skin and soft tissue after repeated expansion for clinical work. METHODS: Six little pigs were divideded as: conventional expansion group, repeated expansion group, and blank control group. Histologic, ultrastructure and bFGF of the skin were observed and measured in each group after samples had been made. RESULTS: The skin and soft tissue after repeated expansion were healthy on the whole. Compared with the conventional expansion group, there was more microscopic change in the repeated expansion group. Collagen fibers were injured evidently. Cells were injured slightly and proliferated much more, and moreover, they were more activated. The content of bFGF was more higher. CONCLUSIONS: The skin and soft tissue after repeated expansion are healthy on the whole by more growth and more repair though repeated expansion may result in more injuries. So repeated expansion is safe and feasible.