Cerebrospinal fluid protein concentrations in children: age-related values in patients without disorders of the central nervous system.

BACKGROUND: The published reference values for cerebrospinal fluid (CSF) total protein concentrations in children suffer from two major drawbacks: (a) the age-related range often is too broad when applied to the steeply falling concentrations in early infancy; and (b) no values have been published for widely used dry chemistry methods. METHODS: We conducted a 2-year retrospective survey of CSF results obtained in a children's hospital with a dry chemistry-based method set up on the Vitros 700 analyzer. RESULTS: The data related to ambulatory children up to 16 years of age and term neonates with no clinical or biological signs of brain disease (n = 1074). Seven age groups with significantly different CSF protein values were identified, and their age-related percentiles (5th, 50th, and 95th) were determined. On the basis of the upper 95th percentile, from age 0 to 6 months the CSF protein concentrations fell rapidly from 1.08 to 0.40 g/L. A plateau (0.32 g/L) was reached from age 6 months to 10 years, followed by a slight increase (0.41 g/L) in the 10-16 years age range. CONCLUSIONS: These results imply that CSF total protein concentrations in the pediatric setting, particularly in infants, must always be interpreted with regard to narrow age-related reference values to avoid false-positive results.

Trophic response of the intestinal mucosa to inflammation in rats injected with turpentine: a study using pair-fed controls.

The effects of restricted food intake and acute inflammation on the small bowel were studied, Wistar rats (250 g) were given subcutaneous injections of turpentine (TR) and compared to two control groups, at 18, 42 and 66 h. One was fed ad libitum (C), the other was pair fed (PF) with TR. The TR and PF rats showed hypoplasia of the jejunal mucosa with decreased protein and DNA contents at 42 h and 66 h. The hypoplasia resulted in a reduced villus height that was significantly different from the controls at 66 h (C: 468 +/- 17, TR[66] : 376 +/- 20, PF[66] : 258 +/- 2.9 microm, P<0.001). This decrease in villus height was significantly greater in the PF rats than in the TR rats at 66 h. The crypt height/villus height (C/V) ratio in the PF rats was greater than in the TR group at all times. However, the protein and DNA contents in the TR group were significantly higher than in the PF group at 42 h and 66 h (TR/PF[42] : 29.5 +/- 1.9 vs 20.5 +/- 2.0, P< 0.001, [66]: 25.8 +/- 2.0 vs 16.6 +/- 1.3 mg/10 cm, P,< 0.001). Disaccharidase activities (sucrase and glucoamylase) per 10 cm jejunum at 66 h were significantly lower in the PF group than in the control and TR groups (sucrase mU/10cm[66] C : 3090 +/- 144, TR 2683 +/- 479, PF 1969 +/- 144, P,< 0.001; glucoamylase mU/10 cm[66] 237 +/- 25, TR 169 +/- 40, PF 123 +/- 5, P< 0.01). The N-aminopeptidase patterns in the TR and PF groups were similar. These data suggest that dietary restriction during acute inflammation is the main factor causing hypoplasia of the jejunal mucosa. However, acute inflammation has a trophic effect on the morphological and function of the mucosa. This effect is probably due to inflammatory mediators, whose synthesis is stimulated by turpentine.

False increase in C-reactive protein attributable to heterophilic antibodies in two renal transplant patients treated with rabbit antilymphocyte globulin.

Increased serum C-reactive protein (sCRP) is a sensitive marker of renal graft rejection. We describe the cases of two children with uncomplicated renal transplantation who had false-positive sCRP values on analyzers using rabbit anti-CRP but values within the reference range with anti-CRP from other animal species. Cross-reaction with heterophilic antibodies was suggested by clinical and biological signs of serum sickness and daily treatment with rabbit antilymphocyte globulin (ALG). The interference depended on the serum concentration of the cross-reactant and was removed by subtotal IgG adsorption to Protein A or Protein G or by immunoadsorption using rabbit ALG or total IgG in non-immune rabbit serum. Anti-rabbit IgG and IgM antibodies were detected in both patients. These are the first reported cases of cross-reaction with heterophilic antibodies in a turbidimetric CRP assay.

Effects of alimentary whole proteins versus their small peptide hydrolysates on liver and skeletal muscle during the acute inflammation phase in the rat.

Acute inflammation induces changes in liver proteins with an increase in synthesis of positive acute-phase proteins such as alpha1-acid glycoprotein (alpha1-AGP) and a decrease in synthesis of negative acute-phase proteins such as albumin. This is associated with muscle wasting, mediated by increased proteolysis and impaired protein synthesis. As protein metabolism can be altered in other situations (malnutrition, growth) by the form of the dietary nitrogen, we studied the effects of the molecular form of nitrogen on liver and skeletal muscle adaptation, looking at gene expression for two acute-phase proteins (albumin and alpha1-AGP) and a number of muscle proteins (alpha1-actin, ubiquitin and C9 proteasome subunit). Two groups of 24 Wistar rats (250 g) were injected S/C with 0.125 ml turpentine/rat and were fed one of two liquid diets. These diets had caloric, nitrogen, carbohydrate and lipid content but differed in the molecular form of the nitrogen source (whole protein [WP] versus peptide hydrolysate [PH]). Liver and muscle adaptation were studied at 18, 42 or 66 h after turpentine injection. Weight, deoxyribonucleic acid and protein content of the liver were significantly higher with the WP diet than with the PH diet at 42 h and 66 h. There was more alpha1-AGP messenger ribonucleic acid (mRNA) at 18 h and less albumin mRNA at 42 h. Thus, the PH diet causes a more rapid increase in alpha1-AGP mRNA content and a smaller decrease in albumin mRNA content after turpentine injection than the WP diet. However, the changes in plasma acute-phase proteins (albumin and alpha1-AGP) were similar with the two diets. In skeletal muscle, there was no change in mRNA levels for the C9 proteasome subunit at any time point with both diets compared to the controls. However, there were greater ubiquitin mRNA levels at 18|h and less alpha-actin mRNA levels at 18 h, 42 h and 66 h following turpentine injection in the two dietary groups than in the controls. These results suggest that the molecular form of nitrogen ingested regulates hepatic gene transcription or mRNA stability of acute-phase proteins, during the early period of inflammation, but did not affect the expression of muscle proteins, which was altered by turpentine injection. Post-transcriptional control of acute-phase protein genes may contribute to the maintenance of similar plasma levels.

Recovery processes after repeated supramaximal exercise at the altitude of 4,350 m.

We tested the hypothesis that prolonged exposure to high altitude would impair the restoration of muscle power during repeated sprints. Seven subjects performed two 20-s Wingate tests (WT1 and WT2) separated by 5 min of recovery, at sea level (N) and after 5-6 days at 4,350 m (H). Mean power output (MPO) and O2 deficit were measured during WT. O2 uptake (VO2) and ventilation (VE) were measured continuously. Blood velocity in the femoral artery (FBV) was recorded by Doppler ultrasound during recovery. Arterialized blood pH and concentrations of bicarbonate ([HCO3-]), venous plasma lactate ([La-]), norepinephrine ([NE]), and epinephrine ([Epi]) were measured before and after WT1 and WT2. MPO decreased between WT1 and WT2 by 6.9% in N (P < 0.05) and by 10.7% in H (P < 0.01). H did not further decrease MPO. O2 deficit decreased between WT1 and WT2 in H only (P < 0.01). Peak VO2 after WT was reduced by 30-40% in H (P < 0.01), but excess postexercise O2 consumption was not significantly lowered in H. During recovery in H compared with N, VE, exercise-induced acidosis, and [NE] were higher, [Epi] tented to be higher, [La-] was not altered, and [HCO3-] and FBV were lower. The similar [La-] accumulation was associated with a higher exercise-induced acidosis and a larger increase in [NE] in H. We concluded from this study that prolonged exposure to high altitude did not significantly impair the restoration of muscle power during repeated sprints, despite a limitation of aerobic processes during early recovery.

Separation and characterization of the main methylated nucleobases from nuclear, cytoplasmic and poly (A)+ RNA by high-performance liquid chromatography and mass spectrometry.

We were able to detect nine methylated nucleobases (3-methyluracil, 1-, 2-, 3- and 7-methylguanine, 1-, 2-, 3- and 6-methyladenine) in RNA from rat and calf liver, baker's yeast, Torula and Euglena cells by using reversed-phase high-performance liquid chromatography and thermospray mass spectrometry. Total cellular, nuclear, cytoplasmic and poly (A)+ RNA from rat liver showed marked methylation, mainly of 1- and 3- methylguanine, and 3- and 2-methyladenine. These bases were especially abundant in nuclear RNA and, to a lesser extent, in poly (A)+ RNA. In contrast, 7-methylguanine and 6-methyladenine were poorly represented in poly (A)+ RNA.

Effect of purified IgGs from HIV-1-infected and non infected individuals on immune activation.

The purification and analysis of IgGs from sera of HIV-1-infected and non infected individuals are reported. The effect of antibodies purified from sera of infected individuals on antigen-induced T cell proliferation was investigated in relation to their possible involvement in an autoimmune reaction in AIDS, in view of the previously unravelled striking peptide similarities between HIV-1 gp120 and the immunoregulatory CD4 and Fas molecules. However, our data do not allow definite conclusions to be drawn. The necessity of purifying antibodies against specific peptides to show their direct effect on T-cell activation is further stressed.

Changes in the glycoforms of rat alpha-1-acid glycoprotein during experimental polyarthritis.

We analyzed the carbohydrate moiety of purified alpha-1-acid glycoprotein (AGP) from Lewis adult male rats that were healthy (AGPh) or had experimental polyarthritis (AGPi). Sodium dodecyl sulfate polyacrylamide gel electrophoresis before and after N-glycanase treatment showed that AGPi had a slightly lower molecular mass (43 kDa vs. 45 kDa for AGPh) due to a lesser carbohydrate content. Carbohydrate analysis of purified AGP showed a slight decrease in the sialyl and galactosyl molar ratio in polyarthritis. However, the same difference in AGPh and AGPi (i.e. 0.6 residue) between the sialyl and galactosyl molar ratio indicated more than one sialyl residue per complex-type branch. Affinity for concanavalin A (ConA) of the whole glycoprotein and released oligosaccharides showed a progression during polyarthritis towards more reactive glycoforms or more ConA-bound oligosaccharides. Anion-exchange HPLC of the ConA-fractionated oligosaccharides corroborated the decreased sialylation in polyarthritis. Taken together, these results suggest a fall in branched and sialylated oligosaccharides during experimental polyarthritis. These structural changes might be related to an increase in Gal beta 1-4GlcNAc alpha 2-6 sialyltransferase activity described elsewhere in inflammatory states.

Oligosaccharide specificity of normal human hepatocyte alpha 1-3 fucosyltransferase.

A purified alpha 1-3 fucosyltransferase (alpha 1-3 FT) was recovered in the Golgi fraction of isolated hepatocytes from normal human liver tissue. The efficiency of purification was controlled by measurement of fucose transfer to asialotransferrin (for alpha 1-3 FT), to phenyl-beta-D-galactose (for alpha 1-2 FT) and to 2' fucosyl lactose (for alpha 1-3/4 FT). The initial hepatocyte isolation step got rid of 97% and 94% of alpha 1-2 and alpha 1-3/4 total liver FT, respectively. After Golgi enrichment (26-fold purification and a yield of 7.6%), alpha 1-3 FT extract expressed a specific activity of 2 pM/min per mg protein. When incubated in optimized conditions with type 1, 2 or 6 oligosaccharide acceptors (10 mM), hepatocellular alpha 1-3 FT efficiently transferred fucose to N-acetyllactosamine and its 3' sialylated derivative, but poorly to lactose. When incubated with neutral or sialylated biantennary N-glycans, the enzyme expressed the highest affinity (Km = 0.38 mM) for the 3'bisialylated derivative. This suggests that hepatocellular alpha 1-3 FT is involved in the synthesis of sialosyl Le(x) determinants on cirrhotic alpha 1AGP.

Determination of cortisol and associated glucocorticoids in serum and urine by an automated liquid chromatographic assay.

We describe a method for the determination of urinary free cortisol and glucocorticoids in plasma, used in the diagnosis of adrenal disorders, based on automated reverse-phase high-performance liquid chromatography (HPLC). The within-day and day-to-day CVs were less than 5.5 and 8.0%, respectively. The calibration curves for cortisol and 11-deoxycortisol were linear up to 2000 nmol/L. Cortisol concentrations as low as 3.5 nmol/L in 1 mL of plasma or urine can be measured. Correlation of HPLC results for 40 plasma specimens with those by radioimmunoassay showed r = 0.965. This method is sensitive and free from the interference habitually encountered in immunoassays, and can thus be proposed for research and as a potential reference method.