Genetic heterogeneity of glycogen storage disease type Ia in France: a study of 48 patients.

Forty-eight patients with glycogen storage disease type Ia (GSD Ia) were studied. Using a combination of single-strand conformation polymorphism (SSCP) analysis, restriction enzyme digestion and direct sequencing, we were able to identify 93/96 mutant alleles, comprising 23 different mutations in the glucose-6-phosphatase gene (G6PC). Among these, 7 are novel mutations of G6PC: M5R, T111I, A241T, C270R, F322L, and two deletions, 793delG and 872delC, resulting in the same mutation at the amino acid level, fs300Ter (300X).

Oxidized low-density lipoprotein induces the production of interleukin-8 by endothelial cells.

The concentration of interleukin-8 (IL-8) and RANTES was measured in culture supernatants of human EA.hy 926 endothelial cells incubated with oxidized low-density lipoproteins (LDL). Oxidized LDL induced a 3-fold increase in IL-8 production (p < 0.01), whereas RANTES was not detected. Native LDL did not stimulate IL-8 production. IL-8 production in oxidized-LDL-treated cells was mediated by reactive oxygen species, as it was partially inhibited by catalase and completely inhibited by glutathione peroxidase and N-acetylcysteine (p < 0.01).

In vitro study of the cytotoxicity of isolated oxidized lipid low-density lipoproteins fractions in human endothelial cells: relationship with the glutathione status and cell morphology.

Toxic effects of oxidized lipid compounds contained in oxidized LDL to endothelial cells are involved in the pathogenesis of atherosclerosis. Glutathione (GSH) plays an important role in the redox status of the cell and in the protective effect against oxidant injuries. However, little is known about the respective effect of these different oxidized lipid compounds toward cytotoxicity and GSH status of the cell. In this report, we isolated by high-performance liquid chromatography oxidized lipid compounds from low-density lipoproteins (LDL) oxidized by copper and we examined their effects on cultured endothelial cells. Cytotoxicity and GSH status were determined after incubation of endothelial cells with crude LDL or isolated lipid fractions derived from cholesterol, phospholipids, or cholesteryl esters. Their effects on cell morphology were also assessed. Oxidized lipids coming from cholesteryl esters (hydroperoxides or short-chain polar derivatives) induced a slight but significant GSH depletion without inducing cytotoxicity. The same species coming from phospholipids induced a more pronounced GSH depletion and a cytotoxic effect which is only present for the more polar compounds (short-chain polar derivatives) and corresponding to a total GSH depletion. In contrast, fractions containing oxysterols had a larger cytotoxic effect than their effect on GSH depletion suggesting that their cytotoxic effects are mediated by a GSH-independent pathway. All together, these data suggest that LDL-associated oxidized lipids present in copper-oxidized LDL exert cytotoxicity by an additional or synergistic effect on GSH depletion, but also by another mechanism independent of the redox status of the cell.

Oxidized-LDL induce apoptosis in HUVEC but not in the endothelial cell line EA.hy 926.

We studied the cytotoxic effect of copper-oxidized LDL in human primary human umbilical vein endothelial cells (HUVEC) and the immortalized EA.hy 926 cell line. Copper oxidized LDL (50-200 microg apoB/ml) induced concentration-dependent apoptotic cell death in HUVEC but did not induce apoptosis in EA.hy 926 cells. Only necrotic EA.hy 926 cells were evidenced at all copper oxidized LDL concentrations (25-200 microg apoB/ml), oxidation states (lightly, moderately and extensively copper-oxidized LDL) and incubation periods (4, 8 and 20 h). The different mechanisms of cell death induced by copper-oxidized LDL in EA.hy 926 cells and HUVEC may be related to various factors such as cytokines. In this study, we investigated whether interleukin-8 may be implicated in this process. The interleukin-8 production was increased in EA.hy 926 cells but not in HUVEC incubated with oxidized LDL. This increase in EA.hy 926 cells was associated with necrosis but not apoptosis. Nevertheless, the addition of interleukin-8 to HUVEC did not inhibit apoptosis induced by oxidized LDL. As the lower antioxidant capacity of EA.hy 926 cells results in higher sensitivity to oxidized LDL cytotoxicity (as we previously described), the redox status of cells may also control the form of endothelial cell death. In atherosclerotic lesions, the formation of apoptotic endothelial cells may result in part from the induction by oxidized LDL.

Benzoselenazolinone derivatives designed to be glutathione peroxidase mimetics feature inhibition of cyclooxygenase/5-lipoxygenase pathways and anti-inflammatory activity.

Two series of compounds, substituted benzoselenazolinones and their opened analogs, diselenides, were prepared. The diselenides were designed according to the available SAR about glutathione peroxidase mimics and were expected to have activity. An initial series of tests was performed in order to assess the glutathione peroxidase and antioxidant activity of the diselenides compared to their cyclized analogs. The diselenides were shown to be very potent (up to 3 times the activity of ebselen), whereas the benzoselenazolinones were inactive, thus confirming our hypothesis. A second series of tests was done to determine the anti-inflammatory potency of the two series. Both were found to be potent on cyclooxygenase and 5-lipoxygenase pathways (up to 95% inhibition at 10(-5) M). Some compounds were selective, and the variations in the activity allowed us to draft some structure-activity relationships. The most interesting compound of each series, 6-benzoylbenzoselenazolinone and bis[(2-amino-5-benzoyl)phenyl] diselenide, was tested in vivo on the rat foot edema induced with different phlogistic agents and was shown to have some anti-inflammatory properties.

Hyperchloremic acidosis during grand mal seizure lactic acidosis.

OBJECTIVE: To evaluate the prevalence and the mechanism of hyperchloremic acidosis component (HClA) during lactic acidosis secondary to grand mal seizures. DESIGN: Retrospective study. SETTING: Medical intensive care unit in a university hospital. PATIENTS: 35 patients admitted for grand mal seizures with lactic acidosis (pH < 7.35, TCO2 < 20 mmol/l and PaCO2 < 8 kPa). MEASUREMENTS: HClA was defined by the ratio: excess anion gap/HCO3 deficit (delta AG/delta TCO2) < 0.8. A difference in the distribution space of protons and their accompanying anion, i.e., a displacement of chloride from cells by the entering lactate, was evaluated by the ratio natremia/chloremia (Na+/Cl-). RESULTS: Immediately after seizures, a profound lactic acidosis was observed (pH = 7.22 +/- 0.17 (mean +/- SD), AG: 23.8 +/- 7.1 mmol/l, TCO2 = 14.5 +/- 5.3 mmol/l, lactate: 14.6 +/- 6.9 mmol/. HClA was present on admission in 11 patients (31.5%). Its prevalence increased to 73% after recovery. delta AG/delta TCO2 ratios were unrelated to creatinine, level and PaCO2, but dependent on the ratio Na+/Cl- (r = 0.803; p < 0.001, delta AG/delta TCO2 = 6.4 x (Na+/Cl-)-7.9). These data demonstrate that HClA is not a respiratory or renal phenomenon and suggest differences in the distribution spaces of hydrogen ions and their accompanying anions. CONCLUSION: HClA component may be associated with lactic acidosis in grand mal seizures and appears to be secondary to a lactate antiport. This phenomenon could be an immediate physiological response to a sudden metabolic acidosis.

Blood lipids and rheological modifications in glycogen storage disease.

OBJECTIVES: Hyperlipidemia is a feature of liver glycogen storage disease (GSD). Recent studies have suggested that rheological mechanisms such as elevated erythrocyte aggregation may be involved in the pathogenesis of ischemic syndromes associated with hyperlipidemia. DESIGN AND METHODS: We investigated erythrocyte aggregation, lipids, and circulatory proteins in the blood of 24 patients affected with GSD, aged from 1 to 23 years (mean = 8) and 26 controls aged from 1 to 28 years (mean = 9). RESULTS: The aggregation results were much higher in patients than controls. The lipid data showed a mixed hyperlipidemia with predominant hypertriglyceridemia, low HDL-C, apoA-I and LpA-I/A-II, and high apoB as compared with controls. However, the LpA-I was not significantly different from controls. CONCLUSIONS: In conclusion, patients with GSD presented hyperlipidemia and elevated erythrocyte aggregation such that they are at long-term risk of ischemic complications.

Decreased erythrocyte deformability in glycogen storage disease.

Liver glycogen storage diseases (GSD) are disorders associated with severe dyslipidaemia which can induce cell membrane alterations and possibly reduced cell deformability. Since decreased erythrocyte deformability is known to disturb blood flow in capillaries and may promote ischaemic diseases, this study was designed to investigate erythrocyte deformability using a new filtration system, the Cell Transit Analyser (CTA), and to examine lipid compounds in the blood of 23 patients affected with GSD, aged from 1 to 20 years and 18 controls aged from 1 to 17 years. The patients showed a mixed hyperlipidaemia with predominant hypertriglyceridaemia and an increase in erythrocytes mean transit times (TT) due to the presence of more rigid erythrocytes subpopulations when compared to controls. Thus the erythrocyte rigidity, in addition to the lipid abnormalities must be taken into account for long-term evolution of GSD patients. Moreover this cellular alteration may contribute to shortened erythrocyte survival.

Effect of ethyl esterification of phenolic acids on low-density lipoprotein oxidation.

Inhibition of copper-induced low-density lipoprotein (LDL) oxidation by phenolic acids and their ethyl esters was investigated. LDL oxidation was evaluated by the hydroperoxide concentration and the chromatographic pattern of apoprotein fractions after fast protein liquid chromatography (FPLC). Antiradical properties against 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical and 2,2'-azobis(2-amidinopropane)dihydrochloride (AAPH) were also investigated, and lipophilicity determined by thin-layer chromatography. Caffeic acid at 5 microM and sinapic acid at 10 microM protected LDL against oxidation, inhibiting both hydroperoxide formation and the increase of apoprotein negative charge. Ferulic, gallic and p-hydroxy cinnamic acids were ineffective. Ethyl esterification increased the lipophilicity of the five acids, and enhanced the antioxidant properties of caffeic, sinapic and ferulic acids. Ethyl caffeate was protective at 1 microM. In contrast, gallic and p-hydroxy cinnamic ethyl esters were ineffective. Our results indicate that ethyl esterification of phenolic acids increases lipophilicity of their ethyl esters and may enable a better incorporation into the lipid layer of the LDL particle and the exertion of their antioxidant effect in the true site of lipoperoxidation. However, increasing lipophilicity is not the only mechanism able to potentiate preexisting antioxidant properties of molecules, and probably other mechanisms are implicated.

Implication of apolipoprotein E and the L-arginine-nitric oxide system in preeclampsia.

OBJECTIVE: During pregnancy, Apolipoprotein (Apo) E is synthesized in the placenta to facilitate the uptake of maternal lipoproteins. Preeclampsia is associated with an abnormal lipid profile. Apo E levels may affect the production of nitric oxide. We investigated whether Apo E variations could be related to the high lipid levels and nitric oxide secretion in preeclamptic women. METHODS: Blood samples from 15 normotensive women and 12 mild and 23 severe cases of preeclampsia were assayed for standard lipid profile, Apo E, and nitrate. Urine samples were analyzed for nitrate and cyclic GMP. RESULTS: In women with mild preeclampsia, the triglyceride concentration was significantly higher (p < 0.05) than in normotensive women (3.30 +/- 1.38 versus 2.31 +/- 0.92 g/L) and associated with a higher (p < 0.01) triglyceride/Apo E ratio (0.71; range = 0.40-1.70). In women with severe preeclampsia, the triglyceride/Apo E ratio was similar to normotensive women [0.39 (range = 0.18-1.19) versus 0.41 (range = 0.18-0.79)] associated with a normal triglyceride level and a twofold higher serum nitrate level [36 (range = 1-63 mumol/L) versus 14 (range = 1-37 mumol/L)]. CONCLUSION: The triglyceride/Apo E ratio is significantly higher in mild preeclampsia. In the severe form, this ratio is similar to that of normotensive pregnant women, probably due to a better uptake of triglyceride. Moreover, in the severe form, it is associated with a twofold normal serum nitrate level. Thus, Apo E and the nitric oxide status may be implicated in preeclampsia.

[Determination of fructosamine on the Cobas-Bio centrifuge system. Importance of white reagent]. / Dosage de la fructosamine sur appareil centrifuge Cobas-Bio. Importance du blanc réactif.

An automated assay for fructosamine on Cobas-Bio centrifugal analyzer with subtracting the contribution of the albumin matrix present in standards is described. This rapid and simple test has suitable analytical performances. Fructosamine concentrations were measured in 100 healthy subjects and in 95 diabetic patients. For the diabetic patients, results were compared with those obtained from a commercialized test kit.

[Enzymatic determination of sodium, potassium and chloride in plasma]. / Le dosage enzymatique du sodium, du potassium et du chlorure dans le plasma.

The Boehringer enzymatic reagents for Na, K and Cl determination on a Hitachi 717 automatic analyser at 37 degrees C were evaluated. Except for Na, the within-run and between-run precision assays gave CV within the SFBC ranges but were higher than those of the comparison analysers: Ektachem 500 Kokak, Dimension Ars Du Pont-De-Nemours and flame photometry. The linear ranges were larger than the usual clinical results. Accuracy, estimated from human controls, was 99 to 103% for Na and K, and 105% for Cl. Comparison of plasma from 102 to 152 patients showed a good concordance for sodium with the Dimension ARS (y = 1x + 0). On the contrary, with Ektachem Kodak, differences appeared, particularly for high values (y = 0.91x + 13.6). For potassium, the concordance was good with flame photometry (y = 1x + 0.1) and Ektachem Kodak (y = 0.94x - 0.16). For chloride, comparison was satisfactory except for high values which were underestimated by the enzymatic method: Dimension ARS (y = 1.03x - 4.8), Ektachem Kodak (y = 0.91x + 9.8). The enzymatic methods were very easy to perform and can be adapted on any autoanalyser at 37 degrees C. We conclude that they are suitable for routine clinical determination. Urinary assays are currently being developed.

[Evaluation of the technique of CKMB assay using Ektachem (500 and 700)]. / Evaluation de la technique de mesure de la CKMB de l'Ektachem (500 et 700).

The aim of this study was to compare the dry-chemistry CKMB Ektachem method to a liquid immunoinhibition method (Merck/Cobas Bio) and to the electrophoretic method (Helena France), both on patients (n = 95) and control (4 specimens from different commercial origin) sera. The Ektachem method was found linear in the range tested (7 to 97 U/l). Within run imprecision tested with low, medium and high control sera were satisfying (CV 3-4%) as well as between run imprecision (CV < 10%), for CKMB activities of at least 30 U/l. As compared to the liquid immunoinhibition method (Merck), the results of patient sera were very close but slightly lower (y = 0.97x-1; r = 0.74; y = Ektachem, x = Merck). As compared to the electrophoretic method, the Kodak Ektachem method showed a specificity of 74% and a sensitivity of 85% (n = 95). A close agreement (r = 0.73) between these two methods was obtained for samples with a total CK activity at least 3 times over the upper limit of normal range. We therefore conclude that the Kodak Ektachem CKMB method allows a rapid and easy determination of CKMB activity for samples undergoing total CK activity 3 times over the upper limit of normal range. Like all liquid immunoinhibition methods, the Kodak Ektachem method shows some lack of specificity and does not show a better concordance with the electrophoretic method than does the Merck/Cobas Bio method.

[Refinement and role of the diagnosis of Gilbert disease with molecular biology]. / Mise au point et intérêt du diagnostic de la maladie de Gilbert par biologie moléculaire.

Gilbert syndrome (GS), characterized by mild, chronic and isolated unconjugated hyperbilirubinemia is due to a partial deficiency of bilirubin-UDP-glucuronosyltransferase (UGT1A1). Recently, the genetic basis of GS has been identified in caucasian populations : it is related to the insertion of a dinucleotide (TA) in the promoter region of the UGT1A1 gene. In Asian populations, GS is due to missense mutations (either homozygous or heterozygous) in the coding sequence. The aim of this study was to develop a simple and rapid method to detect both genetic polymorphisms and mutations. This technique was performed (1) to explore unrelated unconjugated hyperbilirubinemia; (2) to evaluate the frequency of GS in a population of 97 healthy caucasian volunteers: 17% of them were homozygous for the TA7/TA7 polymorphism; (3) to determine the incidence of this syndrome in a population of 105 neonates with unconjugated hyperbilirubinemia. The incidence of GS (15%) was not significantly higher than it was in the control group. A correlation between GS genotype and neonatal jaundice was not established; (4) to seek a relationship between GS and preeclampsia with or without Hellp syndrome. The incidence in the Hellp syndrome group (n = 19) was 26%, two fold higher than in preeclampsia group (n = 22) and control group (n = 50) with only 14% and 13% respectively, (5) to start a study regarding the toxicity of irinotecan treatment in a population of homozygous children for the UGT1A1 polymorphism.

[Concentrations of superoxide dismutase (copper and manganese), catalase and glutathione peroxidase in red cells, platelets and plasma in patients with rheumatoid polyarthritis]. / Concentration en superoxyde dismutase (cuivre et manganèse), catalase et glutathion peroxydase dans les hématies, les plaquettes et le plasma de sujets atteints de polyarthrite rhumatoïde.

Antioxidant enzymes assays (CuZnSOD, MnSOD, catalase glutathione peroxidase) have been performed by radioimmunoassay in erythrocytes, platelets and plasma of rheumatoid polyarthritis patients. No difference has been shown as compared with control subjects whatever the therapy or the length of time for which the patients have been affected. If a deficiency in antioxidant enzymes is related to the destruction of joint tissues by free radicals, it cannot be detected in blood tissue elements.

[Molecular genetics: pre- and post-analytic "best practices"]. / Génétique moléculaire: les << bonnes pratiques>> pré-et postanalytieques.

Medical prescriptions for molecular genetic analyses are not yet very common in general practice, neverless they are becoming more and more frequent, and therefore it is more difficult to deal with them in part because of the recent french rules. Laboratory managers are supposed to be able to deal with such requests. This document, describing good laboratory practices, has been elaborated by members of the group "molecular genetics" from the "College National de Biochimie des Hôpitaux", providing details about: assessment of the prescriptions, including patient's consent, choice of the executing laboratory, specimen transmission, assessment and control of clinical and biological data, results transmission, confidentiality, archiving system. Such recommendations should facilitate exchanges with specialized laboratories, being specifically approved for practicing such analyses. The authors draw the attention of laboratory managers to the specificities of such requests.

[Glutathione peroxidases: value of their determination in clinical biology]. / Les glutathion peroxydases: intérêt de leur dosage en biologie clinique.

The role of glutathione peroxidase in the oxidative metabolism and recent advances in the demonstration of the consequences of the desequilibrium in the proxidant/antioxidant balance on biological molecules oxidation, intracellular signals transduction, apoptosis and necrosis, have led to new approach in the knowledge of many pathological processes. Methods for determining antioxidant capacity have been developed. The measurement of glutathione peroxidase activity is a key step in the study of oxidative stress. Its determination in clinical biology needs optimal conditions for standardised assays which will be used for epidemiological studies aimed to evaluate the role of nutritional factors involved in the pathogeny of diseases caused or accompanied by oxidative stress.

[Vitamin D and pubertal maturation. Value and tolerance of vitamin D supplementation during the winter season]. / Vitamine D et maturation pubertaire. Intérêt et tolérance d'une supplémentation vitaminique D en période hivernale.

BACKGROUND: In France, several cases of vitamin D-deficiency rickets among adolescents have been reported, but no prophylaxis measure has been systematically recommended at this age. The aim of this study was to measure 25-hydroxyvitamin D (25-(OH)D) levels and to search for biological signs of vitamin D deficiency during adolescence. Moreover, the effects of a unique oral dose of 100,000 IU of vitamin D3, given during the winter, were analysed. POPULATION AND METHODS: Circulating levels of 25-(OH)D, 1,25-dihydroxyvitamin D, intact parathyroid hormone (iPTH), alkaline phosphatase activities, calcium and phosphate were measured in 53 adolescents aged 10-17 years (81% of metropolitan origin), seen during the winter. The effect of a single oral dose of 100,000 IU of vitamin D3 or of placebo was studied in 15 of these subjects. RESULTS: 24.5% of the adolescents had low 25-(OH)D concentrations (< 6 ng/ml), this frequency being even more elevated (38%) at the end of pubertal maturation (stages 4 and 5). An increase in iPTH concentrations was found in subjects with lowest 25-(OH)D levels (< 3 ng/ml). An oral dose of 100,000 IU of vitamin D3 resulted in a significant increase in the 25-(OH)D levels; yet, these levels remained within the normal range during the 1-2 month follow-up of the nine treated subjects. This dosage made it possible to correct the low calcium concentrations (2.20-2.24 mmol/l) found before treatment in three adolescents. CONCLUSIONS: The high frequency of low vitamin D status observed during puberty and its normalization after a 100,000 IU vitamin D3 supplementation show the interest and safety of this intermittent 100,000 IU vitamin D3 supplementation to adolescents during the winter season.

[Clinical electrophysiologic properties of magnesium and correlations with its anti-arrhythmia efficacy in acquired torsade de pointes]. / Propriétés électrophysiologiques cliniques du magnésium et corrélations avec son efficacité anti-arythmique dans les torsades de pointe acquises.

Recently, intravenous administration of low doses of magnesium has proved remarkably effective in the treatment of acquired torsade de pointe, but its electrophysiologic effects remain poorly understood. Three clinical cases are reported in three distinct situations (quinidine treatment, hypokalemia, bradycardia with complete atrioventricular block). These cases confirm the efficacy of magnesium, which acts without notable modification of ventricular cycles or the duration of repolarization. In ten patients undergoing intracavitary exploration, the electrophysiologic parameters were analyzed before and after injection of magnesium sulfate (35 mg/kg). Only three parameters were significantly altered; the corrected sinusal recovery time (increase from 245 +/- 92 ms to 296 +/- 96 ms), the effective nodal refractory period (increase from 333 +/- 98 ms to 346 +/- 93 ms), and the Wenckebache period (decrease from 157 +/- 28/min to 144 +/- 21/min). No changes were noted in other parameters, notably ventricular (QT interval, QRS duration, HV interval, and effective ventricular refractory period). The arrhythmic action on the ventricle is therefore remarkable and is not accompanied by patent electrophysiologic effects. The efficacy of magnesium in torsade de pointe may suggest action on calcium currents.

[Fructosamine, a new marker of blood glucose control in the diabetic]. / La fructosamine, nouveau marqueur du contrôle glycémique chez le diabétique.

Serum fructosamine assay is a new, simple and fast method used to evaluate serum glycosylprotein concentrations. We performed this assay in 96 healthy controls, 95 patients with diabetes (insulin-dependent in 71, non insulin-dependent in 24) and 23 non diabetic pregnant women. Serum fructosamine concentrations were increased and correlated with percents of glycosyl haemoglobin in all diabetics, irrespective of the type of diabetes. However, the low correlation coefficient and the fact that some individual values plotted were distant from the regression slope suggested that fructosamine does not have the same biological significance as glycosyl haemoglobin: the formation and degradation kinetics of these two substances are known to be very different. Fructosamine values were tightly close together in controls and in pregnant women, the latter showing lower values.