Phospholipids of normal and experimentally injured spinal cord of the miniature pig

Experimental spinal cord trauma was produced in 3-month-old SS-1 minature pigs by dropping a 25 g weight from a height of 20 cm upon the exposed spinal cord. The histological lesion consisted of edema and hemorrhage. Phospholipid concentration and composition, cholesterol concentration and phospholipid fatty acid composition were determined in whole spinal cord 3 hours after injury, and in spinal cord myelin 5 hours after injury. Three hours after injury phospholipid and cholesterol concentration were decreased by about 14% in the whole spinal cord. Trauma had no effect on the phospholipid composition of whole spinal cord and myelin. Fatty acid composition of myelin also did not change after injury, and changed very slightly in the whole spinal cord. It is concluded that edema following spinal cord trauma is much more extensive than previously assumed. Furthermore, peroxidation of membrane lipid fatty acids does not appear to be a significant factor in spinal cord pathology 3 hours after injury.     

Developmental profiles of gangliosides in mouse and rat cerebral cortex

Summary Developmental profiles of 11 gangliosides, concentration of lipid- and glycoprotein-bound sialic acid, and activity of AChE of the rat and mouse cerebral cortex were followed from the 7^th day of gestation to the 21^st postnatal day.There are three main changes in ganglioside concentration, which are similar in both species. The first occurs from gestation day 10 until birth: parallel to decreased proliferation, cell migration, and neuroblast differentiation, G_M3 and G_D3 in mouse cortex and G_D3 in the rat's decreases in favor of G_Q1b, G_T1b, and G_D1a.The second occurs from birth until the first postnatal week: Parallel to increased growth and arborization of dendrites and axons as well as synaptogenesis in rats and mice, there is a two-fold rise of G_D1a, whereas G_Q1b and G_T1b remain on a nearly constant level. Concomitantly, G_M3 and G_D3 decreases. The third period of ganglioside changes starts in the second postnatal week, parallel to onset of myelination, and is characterized by an increase of G_M1 in parallel with a decrease of the polysialogangliosides G_T1b and G_Q1b.     

Membrane-bound neuraminidase in the developing mouse brain

The specific activity of membrane-bound neuraminidase towards exogenously added gangliosides in the developing mouse brain was investigated. While whole brain was examined in fetuses, studies were carried out comparatively in cortex and cerebellum of postnatal stages. Considerable differences were found among brain areas. There was a rapid increase in forebrain neuraminidase activity before birth. This high level of activity was maintained throughout the first postnatal week, followed by a slow leveling-off to adult values on the 30th day. In the cerebellum a rapid increase in neuraminidase activity occurred between the 10th and 16th postnatal day. After having reached the maximum, enzyme activity declined rapidly, with adult values being reached on the 21st day. Neuraminidase activity in the adult cerebellum exceeds that in the cortex by 65.9 %. The results are discussed in reference to developmental changes in ganglioside metabolism and the possible involvement of neuraminidase in its regulation is pointed out.