Role of inducible nitric oxide synthase and p-selectin in platelet-arteriolar wall adhesion and associated arteriolar constriction during lung reperfusion.

Reperfusion of the ischemic lung causes pulmonary arteriolar vasoconstriction and reduces alveolar perfusion. Lung ischemia-reperfusion (IR) injury leads to platelet and leukocyte activation which could contribute to decreased alveolar perfusion during reperfusion by platelet-arteriolar wall interactions (rolling and adhesion) and subsequent microvascular constriction. During the oxidative stress of ischemia and reperfusion, formation of reactive nitrogen species (RNS) may promote platelet adhesion to the vascular wall with subsequent formation of microthrombi and release of vasoactive substances. Platelets play an important role in causing reperfusion injury in the systemic vasculature through accumulation and release of mediators, but information is lacking about consequences of their interactions with the arteriolar wall in the pulmonary microciculation over the time course of lung reperfusion. During IR induced oxidative stress, overproduction of nitric oxide (NO) could contribute to formation of harmful RNS by interactions with oxygen radicals. The emphasis of the present study was to investigate the relationship between inducible nitric oxide synthase (iNOS), RNS, P-selectin and platelet-arteriolar wall rolling/adhesion and microvascular constriction in the intact lung during the time course of pulmonary ischemia-reperfusion injury. We examined the hypothesis that pulmonary IR induces platelet-arteriolar wall rolling and adhesion (interactions) via a P-selectin dependent mechanism that contributes to pulmonary microvascular constriction during reperfusion. Increased P-selectin expression results from elevated iNOS activity and subsequent RNS generation. Subpleural arterioles, labeled platelets, and leukocytes were examined in anesthetized, open-chest rabbits by intravital fluorescence microscopy. Ischemia was caused by reversibly occluding the right pulmonary artery for 5 min, 1 h or 2 h (5minIR group, 1IR group and 2IR group, respectively). During reperfusion, postischemic platelet rolling and adhesion were independent from leukocyte-arteriolar wall interactions and correlated with pulmonary arteriolar constriction in proportion to the length of ischemia. After 1-h occlusion during reperfusion, platelet rolling was significantly greater than in the 5minIR or control group. Although arteriolar diameters decreased during the first 0.5 h of reperfusion, platelet adhesion was not increased and arteriolar diameters returned to the baseline by 1 h of reperfusion. However, after two hours of ischemia, platelet rolling increased and platelet adhesion was accompanied by arteriolar constriction that was correlated with the level of platelet adhesion after both 1-h and 2-h ischemia. Blockade of systemic P-selectin by Fucoidan (the selectin ligand) inhibited platelet rolling, adherence, and vasoconstriction. Pretreatment of only exogenously labeled platelets with monoclonal antibody (MoAb) to P-selectin prevented platelet rolling and adherence, but not vasoconstriction. In rabbits that were treated with an iNOS inhibitor (1400W) before occlusion (2IR+1400W group), platelet-arteriolar wall interactions and vasoconstriction were prevented. In lung tissue subjected to IR, iNOS activity and expression were markedly greater than control and were also dependent on ischemia duration. Immunochemically detected P-selectin and nitrotyrosine expression in ischemic lung tissue, and the plasma level of soluble P-selectin in 1IR and 2IR groups, were significantly higher than in non-ischemic lungs and were inhibited by pretreatment with 1400W. These results indicate that during reperfusion of the intact lung, pulmonary IR causes platelet rolling and adhesion along arteriolar walls and suggest that this process is mediated by platelet and endothelial P-selectin. The results show that platelet adhesion and arteriolar constriction during early reperfusion can result from increased iNOS activity and is highly correlated with RNS and P-selectin expre

Quality of Residual Neuromuscular Control and Functional Deficits in Patients with Spinal Cord Injury

Study Design: Prospective cohort study. Objective: This study examined the relationship between motor control and clinical function outcomes after spinal cord injury (SCI). Setting: University of Louisville, Louisville, KY, USA. Materials: Eleven persons with SCI and 5 non-injured subjects were included in this study. Methods: The ASIA Impairment Scale (AIS) was used to categorize injury level and severity. Multi-muscle, surface EMG (sEMG) recording, was carried out using a protocol of reflex and volitional motor tasks and was analyzed using a vector-based tool that calculates index values that relate a distribution of multi-muscle activation pattern of each SCI subject to the prototype obtained from non-injured subject group and presents overall magnitude as a separate value. Functional Independence Measure motor sub-scale, Spinal Cord Injury Independence Measure (SCIM-III), and Walking Index for Spinal Cord Injury (WISCI) scale scores were compared to neurophysiological parameters. Results: AIS category and injury level correlated significantly with the WISCI and SCIM mobility sub-scales. sEMG-derived parameters were significantly correlated with SCIM and WISCI scores but only for examinations carried out 48 or more days post-injury. Conclusion: These results supported the hypothesis that clinically relevant function after SCI is related to the degree to which functional organization within the central nervous system is disrupted. Further, due likely to the constraints placed on the expression of functional ability by early post-injury immobilization and hospitalization, neurophysiological assessment of motor function may provide better sensitivity and reliability than can be obtained using the clinical function scales examined here within the early period after injury

Quality of residual neuromuscular control and functional deficits in patients with spinal cord injury

Materials: Eleven persons with SCI and 5 non-injured subjects were included in this study. Methods: The ASIA Impairment Scale (AIS) was used to categorize injury level and severity. Multi-muscle, surface EMG (sEMG) recording, was carried out using a protocol of reflex and volitional motor tasks and was analyzed using a vector-based tool that calculates index values that relate a distribution of multi-muscle activation pattern of each SCI subject to the prototype obtained from non-injured subject group and presents overall magnitude as a separate value. Functional Independence Measure motor sub-scale, Spinal Cord Injury Independence Measure (SCIM-III), and Walking Index for Spinal Cord Injury (WISCI) scale scores were compared to neurophysiological parameters. Results: AIS category and injury level correlated significantly with the WISCI and SCIM mobility sub-scales. sEMG-derived parameters were significantly correlated with SCIM and WISCI scores but only for examinations carried out 48 or more days post-injury. Conclusion: These results supported the hypothesis that clinically relevant function after SCI is related to the degree to which functional organization within the central nervous system is disrupted. Further, due likely to the constraints placed on the expression of functional ability by early post-injury immobilization and hospitalization, neurophysiological assessment of motor function may provide better sensitivity and reliability than can be obtained using the clinical function scales examined here within the early period after injury

Analysis of wet-steam microturbine self-regulation characteristics

The paper analyzes the characteristics of a wet-steam microturbine self-regulation with a constant and variable consumption of a wet steam, depending on the rotor speed of the turbine. The characteristics of self-regulation are the electric power, the consumption load and the torque generated on the microturbine blades. The dependence of electric power on the rotation speed for a wet-steam microturbine with a power of 5 kW is constructed

Analysis of wet-steam microturbine self-regulation characteristics

The paper analyzes the characteristics of a wet-steam microturbine self-regulation with a constant and variable consumption of a wet steam, depending on the rotor speed of the turbine. The characteristics of self-regulation are the electric power, the consumption load and the torque generated on the microturbine blades. The dependence of electric power on the rotation speed for a wet-steam microturbine with a power of 5 kW is constructed

Novel Noninvasive Spinal Neuromodulation Strategy Facilitates Recovery of Stepping after Motor Complete Paraplegia

It has been suggested that neuroplasticity-promoting neuromodulation can restore sensory-motor pathways after spinal cord injury (SCI), reactivating the dormant locomotor neuronal circuitry. We introduce a neuro-rehabilitative approach that leverages locomotor training with multi-segmental spinal cord transcutaneous electrical stimulation (scTS). We hypothesized that scTS neuromodulates spinal networks, complementing the neuroplastic effects of locomotor training, result in a functional progression toward recovery of locomotion. We conducted a case-study to test this approach on a 27-year-old male classified as AIS A with chronic SCI. The training regimen included task-driven non-weight-bearing training (1 month) followed by weight-bearing training (2 months). Training was paired with multi-level continuous and phase-dependent scTS targeting function-specific motor pools. Results suggest a convergence of cross-lesional networks, improving kinematics during voluntary non-weight-bearing locomotor-like stepping. After weight-bearing training, coordination during stepping improved, suggesting an important role of afferent feedback in further improvement of voluntary control and reorganization of the sensory-motor brain-spinal connectome