Anatomical, physiological, and functional connectivity exists between the neurons of the primary motor cortex (M1) and spinal cord. Paired associative stimulation (PAS) produces enduring changes in M1, based on the Hebbian principle of associative plasticity. The present study aimed to establish neurophysiological changes in human cortical and spinal neuronal circuits by pairing noninvasive transspinal stimulation with transcortical stimulation via transcranial magnetic stimulation (TMS). We delivered paired transspinal and transcortical stimulation for 40 min at precise interstimulus intervals, with TMS being delivered after (transspinal-transcortical PAS) or before (transcortical-transspinal PAS) transspinal stimulation. Transspinal-transcortical PAS markedly decreased intracortical inhibition, increased intracortical facilitation and M1 excitability with concomitant decreases of motor threshold, and reduced the soleus Hoffmann's reflex (H-reflex) low frequency-mediated homosynaptic depression. Transcortical-transspinal PAS did not affect intracortical circuits, decreased M1 excitability, and reduced the soleus H-reflex-paired stimulation pulses' mediated postactivation depression. Both protocols affected the excitation threshold of group Ia afferents and motor axons. These findings clearly indicate that the pairing of transspinal with transcortical stimulation produces cortical and spinal excitability changes based on the timing interval and functional network interactions between the two associated inputs. This new PAS paradigm may constitute a significant neuromodulation method with physiological impact, because it can be used to alter concomitantly excitability of intracortical circuits, corticospinal neurons, and spinal inhibition in humans.

Knikou M, Dixon L, Santora D, Ibrahim MM. Transspinal constant-current long-lasting stimulation: a new method to induce cortical and corticospinal plasticity.

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Aim Diabetic (type-2) is a metabolic disease characterized by increased blood glucose level from the normal level. In the present study, apigenin (AG) loaded lipid vesicles (bilosomes: BIL) was prepared, optimized and evaluated for the oral therapeutic efficacy. Experimental AG-BIL was prepared by a thin-film evaporation method using cholesterol, span 60 and sodium deoxycholate. The prepared formulation was optimized by 3-factor and 3-level Box-Behnken design using particle size, entrapment efficiency and drug release as a response. The selected formulation further evaluated for ex-vivo permeation, in vivo pharmacokinetic and pharmacodynamics study. Results The optimized AG bilosomes (AG-BILopt) has shown the vesicle size 183.25 ± 2.43 nm, entrapment efficiency 81.67 ± 4.87%. TEM image showed a spherical shape vesicle with sharp boundaries. The drug release study revealed a significant enhancement in AG release (79.45 ± 4.18%) from AG-BILopt as compared to free AG-dispersion (25.47 ± 3.64%). The permeation and pharmacokinetic studies result revealed 4.49 times higher flux and 4.67 folds higher AUC 0-t than free AG-dispersion. The antidiabetic activity results showed significant (P < 0.05) enhancement in therapeutic efficacy than free AG-dispersion. The results also showed marked improvement in biochemical parameters. Conclusion Our findings suggested, the prepared apigenin loaded bilosomes was found to be an efficient delivery in the therapeutic efficacy in diabetes.

Paclitaxel (PTX) is formulated in a mixture of Cremophor EL and dehydrated alcohol. The intravenous administration of this formula is associated with a risk of infection and hypersensitivity reactions. The presence of Cremophor EL as a pharmaceutical vehicle contributes to these effects. Therefore, in this study, we used human erythrocytes, instead of Cremophor, as a pharmaceutical vehicle. PTX was loaded into erythrocytes using the preswelling method. Analysis of the obtained data indicates that 148.8 lg of PTX was loaded/mL erythrocytes, with an entrapment efficiency of 46.36% and a cell recovery of 75.94%. Furthermore, we observed a significant increase in the mean cell volume values of the erythrocytes, whereas both the mean cell hemoglobin and the mean cell hemoglobin concentration decreased following the loading of PTX. The turbulence fragility index values for unloaded, sham-loaded and PTX-loaded erythrocytes were 3, 2, and 1 h, respectively. Additionally, the erythrocyte glutathione level decreased after PTX loading, whereas lipid peroxidation and protein oxidation increased. The release of PTX from loaded erythrocytes followed first-order kinetics, and about 81% of the loaded drug was released into the plasma after 48 h. The results of the present study revealed that PTX was loaded successfully into human erythrocytes with acceptable loading parameters and with some oxidative modification to the erythrocytes.ª 2013 Production and hosting by Elsevier B.V. on behalf of King Saud University.