CSF amino acid

CSF should be free of any blood contamination because of the marked differences between plasma and CSF amino acid levels. Usually the first milliliter of CSF is used for routine measurements and the second milliliter is used for amino acid analysis. CSF samples are routinely stored at - 80°C. 

The analysis of amino acids has been the first-line approach for the diagnosis of inborn errors of metabolism in most laboratories ever since the end of the 1950s, and it is expected to continue to play this role for a long time. Both the plasma and the CSF amino acid profile are now well known and interpretation should not pose any problems. A correct diagnosis requires adequate pattern recognition [7]. 

CSF amino acids do not show an important age dependence (Table 2.1.7). Levels of most amino acids in the CSF are much lower than in the plasma, the exception being glutamine. The low CSF values bear a certain analytical risk a traumatic lumbar puncture will result in the presence of small amounts of blood in the CSF. This readily influences the CSF amino acid levels and should be interpreted with care. In contrast with some of the neurotransmitter metabolites, no ventral/dorsal gradient for the amino acid is observed. 

A. Tsarbopoulos, B. N. Pramanik, J. Labdon, P. Reichert, G. Gitlin, S. Patel, V. Sardana, T. L. Nagabhushan, and P. P. Trotta, Isolation and characterization of a resistant core peptide of recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF) confirmation of the GM-CSF amino acid sequence by mass spectrometry. Protein Sci. 2 (1993), 1948-1958. 

The conventional amino acid analysis with colorimetric detection often resulted in conflicting data on the normal ammo acid profile of the CSF and hence on the use of CSF ammo acid levels in diagnostics (Hare et al., 1980). The introduction of fluorimetnc, radioreceptor, gas chromatographic, and mass-spectrometnc methods, alone or in combination, has improved the analytical strength of many routine laboratories. We recently utilized the OPA technique for the analysis of CSF amino acids in an unselected group of patients (n = 32) from the Department of Neurology of the university hospital (Table 2). Various aspects of... 

Primary structures of several CSFs have been reported, based on partial protein sequencing and on sequence prediction from cloned cDNA murine GM-CSF [M, 23,000 N. M. Gough et al. Nature 309 (1984) 763-767] murine multi-CSF [M, 23,000-28,000 M. C. Fung et al. Nature 307 (1984) 233-237 T. Yokata et al. Proc. Nall Acad. Scl USA 81 (1984) 1070-1074] human GM-CSF [M, 22,000 G.G. Wong el al. Science 228 (1985) 810-815] human M-CSF M, 45,000 of the homodimer also called CSF-1 E.S. Kawasaki Science 230 (1985) 291-296]. The CSF amino acid sequences determined so far show no homologies, and they display considerable differences in predicted secondary and tertiary structures, which is surprising in view of their extensive functional overlap and the similar response of progenitor cells to different CSFs. 

Perry, T. L., Hansen, S., and Kennedy, J., 1975, CSF amino acids and plasma-CSF amino acid ratios in adults, J. Neurochem. 24 587-589. 

Table F.2 summarizes the metabolites that are observed with NMR in more than 50% of the samples in a body fluid and remain undetected when routine metabolic screening techniques are applied. It is assumed that routine screening comprises measurement of 1. Urine organic acids, amino acids, purines and pyrimidines, monosaccharides and polyols, mucopolysaccharides, oligosaccharides 2. Plasma aminoacids, carnitine (esters), glucose, lactate, pyruvate 3. CSF amino acids and glucose.

G-CSF is also known as pluripoietin and CSI -fl. Two slight variants are known, one consisting of 174 amino acids and the other of 177. The smaller polypeptide predominates and also displays significantly greater biological activity than the larger variant. 

GM-CSF is also known as CSF-a or pluripoietin-a. It is a 127 amino acid, single-chain, glycosylated polypeptide, exhibiting a molecular mass in the region of 22 kDa. It is produced by various cells (Table 10.5), and studies have indicated that its biological activities include ... 

Wagner, M., Coelho, D. M., Barschak, A. G. et al. Reduction of large neutral amino acid concentrations in plasma and CSF of patients with maple syrup urine disease. J. Inker. Metab. Dis. 23 505-512,2000. 

The affect of Li+ on the metabolism of serotonin (5-hydroxytryp-tamine, 5-HT) is equivocal. A number of studies consistently find a Li+-induced increase in the levels of the major metabolite, 5-hydroxyin-doleacetic acid (5-HIAA), in rat brain and in human CSF [155], which appears to reflect an increase in the rate of synthesis of 5-HT [156]. Li+-induced increases in the level of the amino acid precursor, tryptophan, and in the uptake of tryptophan by brain have also been reported [157], implying elevated tryptophan availability during Li+ treatment. In rat brain, chronic Li+ decreases the activity of tryptophan hydroxylase, the enzyme which, when activated by a Ca2+ and calmodulin-dependent protein kinase, leads to the synthesis of 5-HT [158]. Ca2+ increases the strength of binding of tryptophan to the enzyme, whereas Li+ has the opposite effect [159]. Tryptophan uptake is coupled to 5-HT utilization by a negative feedback mechanism and, therefore, the Li+-induced inhibition of tryptophan hydroxylase with a resultant decrease in 5-HT utilization could produce the observed increase in tryptophan uptake. 

G-CSF may be related to IL-6 because both the number and size of in-trons and exons in these two genes are similar. Furthermore, amino acid residues 20-85 in G-CSF and 28-91 in IL-6 have 26% homology, and the positions of four cysteine residues in these regions are precisely conserved. Whilst the IL-6 gene is located on chromosome 7pl5, it may be that the two genes arose from duplication and have since diverged. 

Preliminary information useful in prodrug design has been obtained with amino acids attached to model aromatic amines. Thus, N-(naphthalen-2-yl) amides of amino acids (6.1, R=side chain of amino acid, R =H) proved to be of interest as test compounds to monitor peptidase activity such as ami-nopeptidase M (membrane alanyl aminopeptidase, microsomal aminopepti-dase, EC 3.4.11.2) [16][17], In the presence of purified rabbit kidney aminopeptidase M or human cerebrospinal fluid (CSF) aminopeptidase activity, the rate of hydrolysis decreased in the order Ala-> Leu->Arg->Glu-2-naphthyl-amide. Ala-2-naphthylamide, in particular, proved to be a good test compound, as its rate of hydrolysis was influenced by experimental conditions (preparation, inhibitors, etc.), as was the hydrolysis of a number of low-molecular-weight opioid peptides and circulating vasoactive peptides. 

Atypical dysbetalipoproteinemia, associated with the APOE-313 phenotype rather than the classic APOE-212 phenotype, is characterized by severe hypercholesterolemia and hypertriglyceridemia, xanthomatosis, premature vascular disease, and a preponderance of 3-VLDL. Subjects with atypical dysbetalipoproteinemia are homozygous for an amino acid substitution in APOE at residue 158 (495). In AD, APOE-4 carriers show lower levels of APOE in the CSF compared to controls (496). 

The constant transport of substances among blood, CSF, and brain cells is influenced by the blood-brain barrier (BBB) (Section 3.2.1). The transport function of the BBB depends on the concentration gradient, molecular weight, ion composition, and liposolubility of compounds as well as on the presence of specific transmitters (i.e., glucose and amino acids). 

Thus, for hydrophilic molecules, there is a clear correlation between the CSF/ serum ratio and the hydrodynamic radius of the molecule. This is applicable only in the presence of a steady-state equilibrium (i.e., when the serum concentration is stable and the exchange conditions at the blood-CSF barrier are undisturbed) (Tib). The ratio for water is by definition 1.0. The concentration of the smaller chloride ion is higher in CSF than in serum therefore, in barrier dysfunction, it decreases in comparison to larger molecules. For most amino acids, active... 

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