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Because of the importance of oligodendrocytes (OL) in forming and maintaining myelin in the CNS and the fact that remyelination in the CNS is very limited in contrast to the peripheral nervous system, we investigated the effect of a chemically defined medium OLDEM, previously characterized by the maintenance of mature myelinating OL, on oligodendroblasts (or OL progenitors) in culture. The effect of each component of this medium as well as different combinations of them were also examined. Cultures were examined at different developmental stages immunocytochemically for developmental markers, such as transferrin, sulfatides, myelin basic protein and proteolipid protein. OLDEM accelerated the appearance of developmental markers and concomitant morphological changes. Furthermore, myelin-specific enzymes such as glycerophosphorylcholine phosphodiesterase; p-nitro-phenolphosphocholine phosphodiesterase; 2′3′-cyclic nucleotide 3′-phosphodiesterase and UDP galactose: ceramide galactosyltransferase had enzymatic activities similar to values found in pure myelin, indicating that OLDEM allows the optimal expression of myelin-related genes. The effect of each OLDEM constituent was evaluated by immunocytochemistry and by measurement of enzymatic activities. With each single additive or multiple combinations, oligodendrocytes displayed different degrees of maturation. Deletion of selenium, glucose, and galactose severely affected cell survival as well as enzymes expression in young cultures. However, older cultures were more resistant to these deletions. Putrescine and insulin did not cause such effects on survival, but their absence affected cell maturation. None of the OLDEM additives individually supported survival and/or maturation. Enzyme assays performed on isolated myelin-like membranes or the cells soma revealed a redistribution of the activity between these fractions as the cell matured. The biological role of each of these constituents on the maturation of the oligodendroglial cell is discussed. These observations indicate that OLDEM constituents have a powerful effect on OL progenitor maturation, and membrane formation. This medium will be useful for investigating the remyelination potential of adult OL progenitors.

An oleate dependent form of phospholipase D is present in rat brain neuronal nuclei and both the hydrolytic and transphosphatidylation activities measured. Several acidic phospholipids were found to inhibit this activity in a dose dependent manner. The IC5o values varied from 3.5 ttM for PIP2 to 200 pM for phosphatidic acid. The hydrolysis of PIP2 by phospholipase C would be expected to result in the disinhibition of the oleate dependent phospholipase D activity.

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ExtractRetarded growth, lethargy, motor retardation, and tremor were observed in all offspring from dams subjected to vitamin deficiency during pregnancy or shortly after delivery of litters. Renal development in these animals was delayed and the degree of retardation depended upon the time of initiation of the deficient diet. Uremia, lethargy, motor retardation, and tremor coincided with this maturational delay. T h e degree of reduction of vitamin B 6 in liver and brain bore no systematic relation to the degree of deprivation. Moreover, all symptoms were consistent with the effects of uremia alone. Although cellular mitotic rates were clearly decreased in deprived animals, there was no apparent failure of glomerular neogenesis from diverse vascular, tubular, and subcapsular cellular components. SpeculationRetarded growth, lethargy, motor retardation, and tremor, observed in vitamin B 6-deficient young, were the secondary consequences of uremia which resulted from retarded renal development. This suggests a possible role of vitamin B 6 in kidney morphogenesis. cerebral tissue are direct consequences of failure in vitamin B, is a in metabolic transvitamin B,-dependent enzyme systems. These cerebral formations of amino acids and may also be involved in changes may be indirect consequences of a general the synthesis of compIex lipids. ~h~~ far little is cellular or systemic metabolic failure caused by viknown, however, about those specific metabolic detamin B, deprivation. They may be the consequence rangements, caused by vitamin B6 deprivation, which of uremia, known to occur in vitamin B6-deficient rats lead ultimately to failure of growth and death of the (1-3, 6) and mice [lo]. It was suggested that elevated developing animal. Only cerebral tissue has been exblood urea nitrogen (BUN) reflected increased oxidaamined systematically, where the content of both vition of amino acids for energy production. However, Delayed maturation in vitamin Bg deficiency 547 the possibility that uremia may be the consequence of structural alterations of the kidney was not investigated. T h e purpose of this study is to examine the effect of vitamin B, deprivation on the developing organism by employing simple clinical, morphologic, and biochemical methods of analysis. Morphologic. Liver, kidney, heart, lung, and spleen were excised immediately after decapitation. Tissue were fixed in 10% buffered neutral formalin and embedded in paraffin. Blocks were cut at 6-pm sections and stained with either periodic acid-Schiff reagent or hematoxylin and eosin [ll]. Brains were embedded in albumin-gelatin. Frozen sections were cut at 30 pm and stained with cresylviolet r41. Separate brain sections were stained for myelin by-the ~o i e z method [9]. Biochemical. T h e content of pyridoxal-5'-phosphate in liver and brain samples was quantitated by the tyrosine apodecarboxylase method [13] Offspring from groups I-ZV were killed at 10 and 12 postnatal days while offspring from group ZV only were killed at 19 days. Animals were decapitated and b...