The long-term effects of spinal cord ischemia were studied in 21 rats by lesion scores (LS, n = 21), somatosensory evoked potentials (SEP, n = 16), electromyographic measurements (EMG, n = 12) and histology of the spinal cord (n = 21) 48.5 +/- 57.2 days after 10- to 12-min occlusion of the thoracic aorta and subclavian arteries. All the animals were initially paraplegic with a spastic presentation but seven recovered within 2 days (group A), demonstrating low LS (3.4 +/- 1.05) normal EMGs (n = 3) and unremarkable histology. The 14 paraplegic animals presented relevant findings of the lumbar cord consisting of white matter lesions only (group B, n = 7) or white and gray matter lesions (group C, n = 7). Group B animals showed severe deficit (LS = 11.8 +/- 2.93) without denervation on EMG (n = 5) or muscle atrophy on histology. Group C animals displayed equal impairment (LS = 14.4 +/- 0.71), denervation on EMG (n = 4), and muscle atrophy. Resting motor unit activity of groups B and C were significantly different from group A (p < 0.001), while LS of groups B and C did not differ (p = 0.083). These data underscore the nature and the extent of white matter lesions during spinal cord ischemia, a finding which has generally been eclipsed by emphasis on gray matter lesions in previous studies.

Neonatal hemochromatosis is a specific entity in the spectrum of pediatric liver disease. The clinical course is characterized by progressive deterioration, leading to death within a few days to weeks. The pathologic changes are hepatic fibrosis with massive iron accumulation in hepatocytes. Lesser amounts of iron are found in parenchymal cells of the endocrine organs (adrenal, thyroid, pancreas, pituitary), the heart, and renal tubules. Little iron is present in cells of the reticuloendothelial system. The morphologic pattern thus resembles that of adult idiopathic hemochromatosis. Iron accumulation is a relatively specific finding, as shown by a review of a series of pediatric autopsy cases. Premortem diagnosis of this disease has been made only rarely, and little information is available on laboratory parameters. Recognition of this entity in living neonates is necessary for better understanding of its pathogenesis and treatment.

Occlusion of the thoracic aorta and both subclavian arteries (XC) in the rat model produces spastic paraplegia. In order to characterize the lesion of white matter, 14 male Sprague-Dawley rats underwent XC for 10.5 to 12 min, were observed for 32 days and assessed with a lesion score. A sham group of eight underwent surgical manipulations without XC. The spinal cords were studied by optical microscopy and electron microscopy. An additional group of normal animals (n = 8) underwent spinal cord blood flow measurement with the auto radiographic technique. Optical microscopy showed normal histology in sham operated rats and rats with aortic cross-clamp and lesion score = 2-4 (n = 5), rare changes in the white matter of rats with lesion score = 8 (n = 2), and demyelination of the anterior and lateral tracts of the white matter and motor neuron loss in the gray matter of rats with lesion score = 13-15 (n = 7) and spastic paraplegia. In this last group, electron microscopy disclosed severe axonal degeneration of corticospinal tracts. In the same region spinal cord blood flow was higher than the remaining white matter. This study confirms that spastic paraplegia observed in the rat model after XC is due to degeneration of the pyramidal tracts, perhaps more susceptible to injury due to the high spinal cord blood flow.