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Biomedical subjects

P C Foster

Publications and source records attributed to P C Foster.

8 recordsLinked to original sources
PubMed1984

Phospholipid exchange activity in developing rat brain.

Phospholipid exchange activity has been determined in the supernatant fraction of rat brain from birth through to maturity by measuring the protein-catalysed transfer of total and individual 32P-labelled phospholipids from microsomal membranes to mitochondria, and the transfer of [14C]phosphatidylcholine from liposomes to mitochondria. Transfer activity has also been compared in brain and liver supernatant. Overall phospholipid exchange activity in the brain increased only slightly with age. The activity at birth was 75% of the adult value. However, the transfer of individual phospholipids showed markedly different trends during postnatal brain development. The transfer of phosphatidylinositol (PI) and ethanolamine phospholipids increased postnatally to a maximum at 9 days of age, with lowest values in adult brain. Phosphatidylcholine (PC) transfer increased from 9 days to reach maximum values in the mature brain. The transfer of sphingomyelin was highest immediately after birth. PI transfer activity was higher in brain than liver, while PC and ethanolamine phospholipid transfer activity was higher in liver. The heterogeneity of phospholipid exchange proteins in central nervous system tissue is reflected in the developmental changes in exchange activity towards individual phospholipids. The various exchange proteins appear to have separate induction mechanisms. The presence of exchange-protein activity from birth in the rat indicates the functional importance of phospholipid transport during cell acquisition and membrane proliferation. Activity is not primarily associated with membrane formation such as the formation of the myelin sheath, and therefore is more likely to be involved in the process of phospholipid turnover.

Animals↗
PubMed1984

The activity of 2',3'-cyclic nucleotide 3'-phosphohydrolase in the corpus callosum, subcortical white matter, and spinal cord in infants dying from sudden infant death syndrome.

The activity of 2',3'-cyclic nucleotide 3'-phosphohydrolase (CNPase) has been determined in corpus callosum, subcortical white matter, and spinal cord of infants whose death was attributed to the sudden infant death syndrome (SIDS), and compared with enzyme activity in other cases in which the cause of death was not associated with respiratory distress. In nearly half the SIDS cases, CNPase activity and oligodendroglial cell numbers were reduced before the onset of myelination, but only in the corpus callosum. In other SIDS cases, enzyme activity and cell numbers were the same as in non-SIDS cases. If the expression of CNPase activity reflects glioblast differentiation to oligodendrocytes with myelinating potential, then this transformation is abnormal in certain SIDS cases, as also evidenced in cases of prolonged neonatal respiratory insufficiency and gives rise to a subsequent deficit of myelin in the corpus callosum.

2',3'-Cyclic Nucleotide 3'-Phosphodiesterase↗
PubMed1983

The ontogenic development of 2',3'-cyclic nucleotide 3'-phosphohydrolase in the corpus callosum in relation to oligodendroglial proliferation, myelination and the distribution of fat-containing glial cells.

The development of CNP'ase activity in the corpus callosum of infants dying from different causes has been compared with myelin formation and oligodendroglial proliferation determined by quantitative histological methods. Cases were classified according to the distribution of neutral lipid in capillary endothelia (Class I), with some fat-containing glial cells (Class II) or extensive occurrence of fatty glia (Class III) and compared with Class O cases, showing no neutral lipid accumulation. For cases in Classes II and III--in which nearly all cases of cardiorespiratory insufficiency were classified--there is a deficit of oligodendroglia and myelin, although the ratio of myelin staining intensity to glial cell numbers is similar to Class O cases. The deficit in myelin is due almost entirely to a reduction in oligodendroglial cell numbers. CNP'ase activity is reduced to a greater extent than myelin and the ratio of CNP'ase to glial cell number is reduced before myelination commences. The defect in expression of CNP'ase activity may be indicative of abnormal glioblast transformation. Fatty glial cells are also acquired before myelination suggesting that the primary insult to oligodendroglia, which may be hypoxia, occurs at the time of their proliferation and differentiation. Nearly half the cases of unexplained death in infancy show deficits in CNP'ase activity, correlating with reduced cell numbers and myelin, and the occurrence of fatty glial cells, all of which could be caused by hypoxia around birth.

2',3'-Cyclic Nucleotide 3'-Phosphodiesterase↗
PubMed1976

Changes in the activities of the enzymes of hepatic fatty acid oxidation during development of the rat.

1. Changes in the activities of several enzymes involved in mitochondrial fatty acid oxidation were measured in livers of developing rats between late foetal life and maturity. The enzymes studied are medium- and long-chain ATP-dependent acyl-CoA synthetases of the outer mitochondrial membrane and matrix, GTP-dependent acyl-CoA synthetase, carnitine acyltransferase, enoyl-CoA hydratase, 3-hydroxyacyl-CoA dehydrogenase, general 3-oxoacyl-CoA thiolase and acetoacetyl-CoA thiolase.

Acetyl-CoA C-Acetyltransferase↗
PubMed1976

Changes in hepatic fatty acid degradation and blood lipid and ketone body content during development of the rat.

The following have been measured during the development of the laboratory rat: the rate of oxidation of palmitoylcarnitine, decanoylcarnitine, and 14C-palmitate by liver mitochondria; the concentrations of ketone bodies in the blood; the plasma concentrations of non-esterified fatty acids, glycerol, and triglyceride. In each case, a rise after birth and a fall at weaning were observed. These changes can be correlated with the dietary changes which occur at these times. However, during the suckling period, when a constant high fat content diet is consumed, further marked changes in the parameters measured were observed which cannot be related to nutritional factors.

Age Factors↗