Evidence for increased lipid peroxidation in multiple sclerosis.

Pentane and ethane are degradation products of unsaturated fatty acids which are released during lipid peroxidation. In order to assess whether multiple sclerosis is associated with lipid peroxidation, we measured pentane and ethane excretion by 16 patients with multiple sclerosis and compared them to healthy control subjects. Patients with acute exacerbation of multiple sclerosis had significantly higher concentrations of pentane (10.5 +/- 4.2 nmol/l)(p less than 0.01) compared to either patients in remission (4.5 +/- 1.7 nmol/l) or control subjects (4.9 +/- 1.1 nmol/l). The concentrations of ethane were not significantly different among these groups. Of the patients with acute exacerbation who later achieved remission, the pentane excretion also returned to normal (5.6 +/- 0.9 nmol/l). One patient who failed to reachieve clinical remission continued to excrete large amounts of pentane. We conclude that oxygen free radical activity is enhanced during exacerbation of multiple sclerosis.

Secretion of plasminogen activator by cerebral astrocytes and its modulation.

Plasminogen activator (PA) has been related to the neuron migration during brain development. PA has also been shown to degrade myelin basic protein. We present data to show that neonatal Balb/c astrocytes show PA activity on 125I-fibrin coated plates. Secreted and cell associated fibrinolytic activity is detected only in the presence of plasminogen. Modulants like concanavalin A and phorbol myristate acetate enhance PA production and this function involves a transcriptional event. Dexamethasone inhibits baseline as well as concanavalin A induced enhancement of PA activity. These results raise the possibility that astrocytes may have an active role in myelinoclastic disorders and CNS developmental defects.

Characterization of astrocyte plasminogen activator.

We have previously shown that astrocytes produce and secrete plasminogen activator (PA) and that this function is responsive to various modulating agents. When astrocyte conditioned medium (CM) is subjected to SDS-PAGE and PA activity localized by fibrin-agar gel overlay, the activity in the CM is found to comigrate with control t-PA. On affinity chromatography CM PA specifically binds to t-PA antibody. The latter also inhibits fibrinolytic activity of CM PA. When incubated with a fibrin clot, CM PA activity can be shown to bind to fibrin. These observations help identify the enzyme in astrocyte CM as t-PA. A possible role of astrocyte PA in myelin injury could provide an explanation for the previously observed correlation between fibrin deposition and demyelination as well as inhibition of demyelination by ancrod and heparin in experimental allergic encephalomyelitis.

Spinal epidural lipomatosis: report of a case secondary to hypothyroidism and review of literature.

Epidural lipomatosis usually occurs as a complication of steroid therapy. This report includes the first description of a case secondary to hypothyroidism. Adults in all age groups can be affected and present with progressive signs and symptoms of spinal cord or cauda equina compression. The dorsal aspect of the thoracic spine is most commonly involved, usually in its total extent. Spine radiographs are normal and myelography poorly delineates the nature and extent of abnormality. While computed tomography can provide information about the nature of the spinal mass, magnetic resonance imaging is the investigation of choice. Extensive decompressive laminectomy is useful but the results are variable. Correction of underlying endocrine abnormality can reverse the process. The need for early diagnosis of this disorder is therefore emphasized.

Purtscher's retinopathy secondary to pancreatitis. Aspects of the topography of retinal abnormalities.

A 22-year-old man with acute pancreatitis developed sudden bilateral blindness with funduscopic features of Purtscher's retinopathy. The topography of retinal abnormalities has been ascribed to the properties of the retinal capillary network. However, the similarity between the distribution of the retinal abnormalities and the density of the nerve fiber layer suggests that the observed topography may, in fact, result from the anatomical characteristics of the nerve fiber layer.