Aberrant crossed corticospinal facilitation in muscles distant from a spinal cord injury.

Crossed facilitatory interactions in the corticospinal pathway are impaired in humans with chronic incomplete spinal cord injury (SCI). The extent to which crossed facilitation is affected in muscles above and below the injury remains unknown. To address this question we tested 51 patients with neurological injuries between C2-T12 and 17 age-matched healthy controls. Using transcranial magnetic stimulation we elicited motor evoked potentials (MEPs) in the resting first dorsal interosseous, biceps brachii, and tibialis anterior muscles when the contralateral side remained at rest or performed 70% of maximal voluntary contraction (MVC) into index finger abduction, elbow flexion, and ankle dorsiflexion, respectively. By testing MEPs in muscles with motoneurons located at different spinal cord segments we were able to relate the neurological level of injury to be above, at, or below the location of the motoneurons of the muscle tested. We demonstrate that in patients the size of MEPs was increased to a similar extent as in controls in muscles above the injury during 70% of MVC compared to rest. MEPs remained unchanged in muscles at and within 5 segments below the injury during 70% of MVC compared to rest. However, in muscles beyond 5 segments below the injury the size of MEPs increased similar to controls and was aberrantly high, 2-fold above controls, in muscles distant (>15 segments) from the injury. These aberrantly large MEPs were accompanied by larger F-wave amplitudes compared to controls. Thus, our findings support the view that corticospinal degeneration does not spread rostral to the lesion, and highlights the potential of caudal regions distant from an injury to facilitate residual corticospinal output after SCI

Diagnosis of inflammatory demyelination in biopsy specimens: a practical approach

Multiple sclerosis is the most frequent demyelinating disease in adults. It is characterized by demyelination, inflammation, gliosis and a variable loss of axons. Clinically and histologically, it shares features with other demyelinating and/or inflammatory CNS diseases. Diagnosis of an inflammatory demyelinating disease can be challenging, especially in small biopsy specimens. Here, we summarize the histological hallmarks and most important neuropathological differential diagnoses of early MS, and provide practical guidelines for the diagnosis of inflammatory demyelinating diseases

Rapid estimation of split renal function in kidney donors using software developed for computed tomographic renal volumetry

Purpose: To evaluate the speed and precision of split renal volume (SRV) measurement (SRV), which is the ratio of unilateral renal volume to bilateral renal volume, using a newly developed software for computed tomographic (CT) volumetry and to investigate the usefulness of SRV for the estimation of split renal function (SRF) in kidney donors. Method: Both dynamic CT and renal scintigraphy in 28 adult potential living renal donors were the subjects of this study. We calculated SRV using the newly developed volumetric software built into a PACS viewer (n-SRV), and compared it with SRV calculated using a conventional workstation, ZIOSOFT (z-SRV). The correlation with split renal function (SRF) using 99mTc-DMSA scintigraphy was also investigated. Results: The time required for volumetry of bilateral kidneys with the newly developed software (16.7 ± 3.9 sec) was significantly shorter than that of the workstation (102.6 ± 38.9 sec, p < 0.0001). The results of n-SRV (49.7 ± 4.0%) were highly consistent with those of z-SRV (49.9 ± 3.6%), with a mean discrepancy of 0.12 ± 0.84%. The SRF also agreed well with the n-SRV, with a mean discrepancy of 0.25 ± 1.65%. The dominant side determined by SRF and n-SRV showed agreement in 26 of 28 cases (92.9%). Conclusion: The newly developed software for CT volumetry was more rapid than the conventional workstation volumetry and just as accurate, and was suggested to be useful for the estimation of SRF and thus the dominant side in kidney donors