Biochemistry

Acta Nrurol Scand 1W7 95. 96-98 Printed in V Kall rrghts reserved Copyright 0 Munksgaard 1997 ACTA NEUROLOGICA SCANDINAVICA ISSN 0001-6314 Amino acid concentrations in cerebrospinal L fluid of patients with multiple sclerosis KlivCnyi P, Kekesi K, JuhAsz G, VCcsei L. Amino acid concentrations in cerebrospinal fluid of patients with multiple sclerosis. Acta Neurol Scand 1997: 95: 96-98. 0 Munksgaard 1997.

HERNANZ, A. 1990. Characterization and distribution of bombesin-like peptides in the rat brain and gastrointestinal tract. Biochem. Cell Biol. 68: 1142-1 145. Extracts of rat brain and gastrointestinal tract, analyzed by reverse-phase high-performance liquid chromatography and radioimmunoassay, contained two bombesin-like immunoreactivity peaks with similar retention times as porcine gastrin-releasing peptide (GRP) and its COOH-terminal decapeptide, neuromedin C or GRP(18-27). However, the GRP-like peptide peak did not elute with exactly the same retention time as porcine GRP. The highest concentration of bombesin-like immunoreactivity was found in extracts of antrum, whereas the lowest was found in whole brain. Neuromedin C was present at lower concentrations than the GRP in antrum, duodenum, and ileum, while similar amounts of each were found in brain.

To investigate the possible existence of age-related changes in excitatory amino acid release in brain, and the influence of glucose deprivation on this process, we have determined the release of endogenous aspartate and glutamate from synaptosomes freshly isolated from the cerebrum of young (12 months old)~and aged (24 months old) mice. We found that there are no age-related changes in the synaptosomal release of aspartic and glutamic acids. However, in the absence of glucose in the medium of incubation aspartate and glutamate release was higher in old than in young animals (P < 0.05, and P = 0.09 respectively). Our results suggest that the ability of cerebral synaptosomes to release glutamate and aspartate remains functionally intact in old cerebrum, but there is an age-dependent dysfunction in this process linked to energy metabolism disturbances.

Since moderate hyperhomocysteinemia is an independent risk factor for vascular disease and physiological thiol compounds mediate Cu 2ϩ -and Fe 3ϩ -dependent low-density lipoprotein (LDL) oxidation, we have studied the total plasma concentrations of thiol compounds including methionine as precursor of homocysteine in rheumatoid arthritis patients, in which the high mortality found is associated with cardiovascular disease. Design and methods: Thirty-eight women with rheumatoid arthritis and 25 age-matched control women were studied. Plasma was used to measure thiol compounds and amino acids by HPLC. Results: Rheumatoid arthritis patients showed significantly higher levels than healthy controls of total plasma homocysteine (17.3 Ϯ 7.8 vs. 7.6 Ϯ 1.9; p Ͻ0.001), cysteine (293 Ϯ 61 vs. 201 Ϯ 45; p Ͻ 0.001), cysteinglycine (32.7 Ϯ 8.3 vs. 22.3 Ϯ 4.7; p Ͻ 0.001) and methionine (25 Ϯ 9 vs. 18 Ϯ 3; p Ͻ 0.01), whereas total glutathione levels were not increased (4.7 Ϯ 2.0 vs. 4.1 Ϯ 1.6).

Overview: In newborns with symptomatic congenital cytomegalovirus (CMV) infection, neuroimaging is the best available predictor of neurodevelopmental outcome. Cerebrospinal fluid (CSF) findings in congenital CMV infection have seldom been described. Neonates with central nervous system infections present high CSF Beta 2 -microglobulin (β 2 -m) levels.

Some children with coeliac disease show behavioural disorders such as depression and other signs which have been correlated with reduced central monoamine metabolism. We have therefore investigated the brain availability of the monoamine precursors tryptophan and tyrosine in 15 untreated children with coeliac disease and 12 treated children with coeliac disease as well as in 12 control children. Significantly decreased plasma concentrations of tryptophan were found in untreated children (mean (SD) 13 (4) ,mol/l, p<0.001) compared with treated children (31 (13) ,mol/l), and in both groups of coeliac children when compared with control children (81 (22) gumoUll). A significantly lower ratio of plasma tryptophan to large neutral amino acids (tyrosine, valine, isoleucine, leucine, and phenylalanine) was also observed, which could indicate impaired brain availability of tryptophan in coeliac children and was more pronounced in untreated children. The impaired availability of tryptophan could produce decreased central serotonin synthesis and in turn behaviour disorders in children with coeliac disease.

The age-related deterioration of the function of immune cells, or immunosenescence, is based on oxidative stress (an imbalance between the levels of oxidants and antioxidant defences with an increase of the former). Accordingly, the ingestion of a diet supplemented with thiolic antioxidants such as N-acetylcysteine (NAC), a glutathione precursor, by aged subjects improved their leucocyte functions. The aim of the present study was to show if NAC improves in vitro several functions of leucocytes from chronologically old mice and if this antioxidant is able to bring the values of these functions to the levels of those of adult animals. Six concentrations of NAC (in a range from 0.001 mM to 2.5 mM) were investigated on several functions of peritoneal leucocytes from old (78±2 weeks of age) BALB/c mice. These functions were those of the phagocytic process in macrophages, namely: adherence to substrate, directed migration or chemotaxis, phagocytosis of inert particles and superoxide anion levels as a measure of digestion capacity, as well as of the adherence and chemotaxis of lymphocytes. These functions were also studied in peritoneal leucocytes from adult (18±2 weeks of age) mice. The results showed that NAC in vitro improves all the functions studied, especially at the highest concentrations, which had shown impaired values in old mice, approaching those of adult animals. Since the immune functions studied are markers of health and predictors of longevity, the administration to aged subjects of NAC, which shows a direct action in leucocytes, seems to be a good strategy to improve their immune system and, therefore, to reach a healthy longevity.

We have studied the effects in vitro of gastrin-17 and gastrin-34, at concentrations from 10\m=-\14m to 10\m=-\6m, on several of the functions of peripheral blood human neutrophils, i.e. adherence to substrate, mobility (spontaneous and directed by a chemical gradient or chemotaxis), ingestion of inert particles (latex beads) and cells (Candida albicans) and superoxide anion production. Both gastrins inhibited several steps of the phagocytic process of human neutrophils, such as mobility and ingestion. By contrast, these peptides increased adherence and had no effect on superoxide anion production. In general, these effects were significant at peptide concentrations between 10 \m=-\12m and 10\m=-\8 m with a maximal effect at 10 \m=-\10m.

Thiamine is an essential cofactor for several important enzymes involved in brain oxidative metabolism, such as the alpha-ketoglutarate dehydrogenase complex (KGDHC), pyruvate-dehydrogenase complex (PDHC), and transketolase. Some investigators reported decreased thiaminediphosphate levels and decreased activities of KGDHC, pyruvatedehydrogenase complex and transketolase in the brain tissue of Alzheimer's disease (AD) patients. We measured cerebrospinal (CSF) levels of thiaminediphosphate, thiamine-monophosphate, free thiamine, and total thiamine, using ion-pair reversed phase high performance liquid chromatography, in 33 patients with sporadic AD and 32 matched controls.

Bombesin and the two mammalian bombesin-related peptides, gastrin-releasing peptide (GRP) and neuromedin C, at physiological concentrations ranging from 10 -11 M to 10 -9 M have been shown in this study to significantly stimulate in vitro the antibody-dependent cellular cytotoxicity (ADCC) and natural killer (NK) activities in BALB/c mouse leukocytes from axillary nodes, spleen and thymus. The three neuropeptides studied induced no change in interleukin-2 production. In addition, these neuropeptides induced in leukocytes from axillary nodes a rapid, transient and significant decrease of intracellular cyclic AMP at 30 s, but a significant transient increase of inositol 1,4,5-trisphosphate levels at 30 and 60 s and a stimulation of protein kinase C activity in membrane fractions after 5 min incubation. These results suggest that inositol phospholipid signalling and cAMP messenger systems are involved in the increase of NK and ADCC activities when leukocytes are incubated in the presence of bombesin, GRP or neuromedin C.

We studied interleukin-1/3 (IL-1/3), /32-microglobulin (/3z-m) , /3-endorphin, substance P, neuropeptide Y and somatostatin concentrations in the cerebrospinal fluid of 13 patients with dementia of the Alzheimer type (DAT), 13 patients with multi-infarct dementia (MID) and 15 age-matched control subjects. Substance P was significantly lower in DAT than in controls (P < 0.05), as well as somatostatin in DAT as compared to both controls (P < 0.01) and MID (P < 0.05), whereas /32-m was higher in DAT than in controls (P < 0.01). Neuropeptide Y, /3-endorphin and IL-1/3 showed similar concentrations in the three groups studied. A significantly positive correlation was observed between IL-1/3 and substance P (r = 0.79, P < 0.01) and somatostatin (r = 0.75, P < 0.05) in DAT, which was not observed in MID. In addition, /32-m showed a negative correlation with IL-1/3 (r = -0.73, P < 0.05) in DAT, and age correlated negatively with IL-1/3 in controls and MID, but positively in DAT. Therefore, these results support the idea that an altered relationship may exist in Alzheimer's disease between the nervous and immune system.

The neuropeptides neurotensin and neuromedin N (from 10 ~2 M to 10 -~ M) have been shown in this study to stimulate significantly in vitro several steps of the phagocytic process: adherence to substrate, chemotaxis, ingestion of inert particles (latex beads) and production of superoxide anion measured by nitroblue tetrazolium reduction in resting peritoneal macrophages from BALB/c mice. A dose-response relationship was observed, with a maximal stimulation of the phagocytic process at 10 ~1 M. The two neuropeptides induced no change of intracellular cyclic AMP in murine macrophages. Moreover, adherence and chemotaxis decreased significantly in the presence of EGTA (1 raM), a chelator of extracellular Ca 2+, or ryanodine (0.5 raM), a blocker of a Ca-~+-gated channel from the endoplasmic reticulum, in both controls and samples with the addition of neurotensin or neuromedin N. These results suggest that there is no relation between the cAMP messenger system and the phagocytic process stimulation in murine peritoneal macrophages by neurotensin or neuromedin N. In addition, the results observed with EGTA and ryanodine could indicate that these two neuropeptides produce their effects through an increase of intracellular Ca 2 + concentration.

is a difficult diagnosis because of the limitation of standard cerebrospinal fluid (CSF) tests. This limitation means that new markers in CSF tests are needed to establish whether meningitis is present in presumptive cases of CS. b 2 -Microglobulin (b 2 -m) is raised in CSF recovered from neonates with central nervous system (CNS) infections, but it does not correlate with cellular count or proteins in the CSF. We present a preterm newborn with symptomatic CS. First-day CSF showed 50 cells/mm 3 , protein of 220 mg/dL and a b 2 -m concentration of 16.9 mg/dL (normal -2.25 mg/dL). Serial determinations of b 2 -m showed a marked reduction (76%) after 10 days of appropriate treatment. At 30 days of life, b 2 -m was already within the normal range (1.8 mg/dL). Cerebral ultrasonography showed ventricular dilatation, moderate periventricular echogenicity, subependimal hemorrhages, and linear hyperechoic areas in the thalamus and basal ganglia. We suggest that b 2 -microglobulin is very useful in the diagnosis of CNS involvement and in monitoring the response to treatment. In addition, infants with CS may exhibit CNS imaging findings similar to those observed in other intrauterine CNS infections.

To study the possible role of several amino acids on feeding in the anorexia of aging, we have measured plasma and cerebrospinal fluid (CSF) concentrations of 22 amino acids in 14 elderly persons with idiopathic anorexia and 10 healthy subjects with normal weight in a similar age range. Plasma and CSF amino acid concentrations and CSF homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA) levels were all measured by HPLC methods. Elderly anorectic subjects had significantly lower levels of glutamie acid but increased concentrations of glutamine in both plasma and CSF compared to controls. Likewise, a significant increase of histidine, threonine, alanine, arginine, valine, methionine, isoleucine, leucine, phenylalanine, tryptophan, ornithine and lysine was found in CSF, but not in plasma, from patients with anorexia. Besides, the CSF histidine/LNAA (large neutral amino acids) and tryptophan/LNAA ratios were elevated in anorectie patients as compared with controls of similar age. In addition, we found higher CSF concentrations of HVA and 5-HIAA, as well as a positive correlation between CSF LNAA and either HVA (r=0.74, p=0.002) or 5-HIAA (r=0.61, p=0.020) concentrations in elderly anorecties. CSF tryptophan correlated positively with 5-HIAA levels (r=0.59, p=0.026) and CSF tyrosine with HVA levels (r=0.77, p=0.002). Our results suggest that changes in the CSF concentration of amino acids could contribute to an increased biogenie amine metabolism in the central nervous system of elderly anorectic subjects, possibly increasing the synaptic liberation of biogenie amines involved in the appetite regulation.