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The low 5-methyltetrahydrofolate (5MTHF) level in the cerebrospinal fluid of patients with cerebral folate deficiency is a consequence of impaired transport across the blood-brain and blood-cerebrospinal fluid barriers. Cerebral folate deficiency is caused by circulating autoaniboides that block the binding of folate to the glycosylphosphatidylinositol (GPI)-anchored folate receptors.

We exploited the high rate of homologous recombination shown by the chicken B cell line DT40 to inactivate the endogenous alleles for clathrin heavy chain and replace them with human clathrin complementary DNA under the control of a tetracycline-regulatable promoter. Clathrin repression perturbed the activities of Akt-mediated and mitogen-activated protein kinase-mediated signaling pathways and induced apoptosis; this finding suggests that in DT40 cells clathrin helps to maintain the integrity of antiapoptotic survival pathways. We also describe a variant cell line in which these signaling pathways were unaffected by clathrin down-regulation. This variant cell line did not undergo apoptosis in the absence of clathrin and was used to examine the effects of clathrin depletion on membrane-trafficking pathways. Receptor-mediated and fluid-phase endocytosis were both substantially inhibited, and transferrin-receptor recycling was modestly inhibited. Surprisingly, clathrin removal did not affect the morphology or biochemical composition of lysosomes., Clathrin-coated vesicles play a fundamental role in eukaryotic cells. They internalize selected cell-surface molecules by receptor-mediated endocytosis (RME) and are implicated in the export of lysosomal enzymes from the trans-Golgi [...]

Capillary electrophoresis with laser-induced fluorescence detection is used to analyze 10 [[micro]liter] samples of human cerebrospinal fluid. Primary amine-containing compounds in untreated cerebrospinal fluid are labeled with 3-(4-carboxybenzoyl)-2-quinolinecarboxaldehyde prior to analysis, producing fluorescent isoindoles. Electropherograms containing approximately 50 peaks are obtained in less than 35 min from cerebrospinal fluid samples. Ten peaks in the electropherograms have been identified and quantitated: arginine, glutamine, threonine, valine, [Gamma]-amino-n-butyric acid, serine, alanine, glycine, glutamic acid, and aspartic acid. Detection limits for these 10 amino acids range from 0.29 nM for [Gamma]-amino-n-butyric acid to 100 nM for threonine, and separation efficiencies as high as 190 000 theoretical plates are obtained for these analytes. Electropherograms of cerebrospinal fluid samples from patients with Alzheimer's disease and from children with different neurological disorders are compared to those of healthy controls. Differences in individual amino acid levels are observed between the patient groups, and these differences appear to be disease and age related. These results indicate that analysis of cerebrospinal fluid by capillary electrophoresis will be useful as a selective, rapid, and sensitive tool for both diagnosis of central nervous system disorders and for study of the mechanisms of these disorders.

Addition of amyloid beta protein (Abeta) to cerebrospinal fluid (CSF) of patients with Alzheimer's disease and normals reveals that transthyretin (TTR), a CSF protein, sequesters Abeta protein into stable complexes. Sequestration prevents aggregation of Abeta proteins leading to amyloid fibrils, which are associated with Alzheimer disease. In vitro studies show that apolipoprotein E does not complex with Abeta in CSF.

A study was conducted relating to chemokine involvement in leukocyte extravasion from both central nervous system and peripheral vascular beds. High resolution confocal microscopy and and three-dimensional image reconstruction were performed, for the first time, to reveal the perivascular binding of the monocyte chemoattractant protein-1 and macrophage inflammatory protein-1-alpha chemokines. It also aimed to delineate the cellular and molecular binding domains. Results are discussed.