Acute spinal cord injury: MR imaging at 1.5 T

Thirty-seven magnetic resonance (MR) imaging studies were performed with a 1.5-T magnet and surface coils in 27 patients with suspected spinal cord injuries. Imaging was performed 1 day to 6 weeks after injury. Cord abnormalities were seen with MR in 19 patients, while skeletal and/or ligamentous injuries were seen in 21 (78%). Three types of MR signal patterns were seen in association with cord injuries. Acute intraspinal hemorrhage was seen in five patients with cord injuries and demonstrated decreased signal intensity on T2-weighted images obtained within 24 hours of injury. Cord edema and contusion had high signal intensity on T2-weighted images and were observed in 12 cases with cord injury. Neurologic recovery, determined in 16 patients, was insignificant in patients with intraspinal hemorrhage; however, patients with cord edema or contusion recovered significant neurologic function. MR at 1.5 T is extremely useful in the diagnosis of acute cord injury and also demonstrates potential in predicting neurologic recovery.     

Numerical Simulation of Enhanced External Counterpulsation

Enhanced external counterpulsation (EECP) is a noninvasive, counterpulsative method to provide temporary aid to the failing heart by sequentially inflating cuffs on the lower extremity out-of-phase with the left ventricle. Optimization of the method necessitates consideration of the hemodynamics created by EECP and the mode of action providing patient benefit. A computational model based on the governing one-dimensional equations is developed that simulates cardiovascular hemodynamics during EECP. The model includes a 30-element arterial system including the left ventricle, bifurcations, and peripheral arterial vessels. Effects of vessel collapse as external pressure is applied, arterial refilling on pressure release, changes in aortic pressure, and shear stress generated in the arteries are each investigated. Device parameters are systematically varied to determine their effect on system performance. Results show the potential for significant collapse and shear augmentation throughout the arteries of the lower extremity. Performance is strongly influenced by the mean level of external pressurization and the timing of cuff inflation, but less so by the relative timing and pressure differences between cuff segments. © 2001 Biomedical Engineering Society. PAC01: 8719Uv, 0260Cb, 8710+e, 8780-y     

Early postnatal gene expression in the developing neocortex of prairie voles (Microtus ochrogaster) is related to parental rearing style

The earliest and most prevalent sensory experience includes tactile, thermal, and olfactory stimulation delivered to the young via contact with the mother, and in some mammals, the father. Prairie voles (Microtus ochrogaster), like humans, are biparental and serve as a model for understanding the impact of parent/offspring interactions on the developing brain. Prairie voles also exhibit natural variation in the level of tactile stimulation delivered by the parents to the offspring, and this has been well documented and quantified. Previous studies revealed that adult prairie vole offspring who received either high (HC) or low (LC) tactile contact from their parents have differences in the size of cortical fields and the connections of somatosensory cortex. In the current investigation, we examined gene expression, intraneocortical connectivity, and cortical thickness in newborn voles to appreciate when differences in HC and LC offspring begin to emerge. We observed differences in developmentally regulated genes, as well as variation in prelimbic and anterior cingulate cortical thickness at postnatal Day 1 (P1) in HC and LC voles. Results from this study suggest that parenting styles, such as those involving high or low physical contact, impact the developing neocortex via very early sensory experience as well as differences in epigenetic modifications that may emerge in HC and LC voles.