Comparison of serum copper determination by colorimetric and atomic absorption spectrometric methods in seven different laboratories. The S.F.B.C. (Société Française de Biologie Clinique) Trace Element Group.

An interlaboratory collaborative trial was conducted on the determination of serum copper using two different methods, based on colorimetry (test combination Copper, Boehringer Mannheim, Mannheim, Germany) and flame atomic absorption spectrometry (FAAS). The general performance of the colorimetric method was below that of FAAS, except for sensitivity and linear range, as assessed by detection limit (0.44 versus 1.32 mumol/L) and upper limit of linearity (150 versus 50 mumol/L). The range of the between-run CVs and the recovery of standard additions were, respectively, 2.3-11.9% and 92-127% for the colorimetric method and 1.1-6.0% and 93-101% for the FAAS method. Interferences were minimal with both methods. The two techniques correlated satisfactorily (the correlation coefficients ranged from 0.945-0.970 among laboratories) but the colorimetric assay exhibited slightly higher results than the FAAS method. Each method was transferable among laboratories.

[Anomalies in fatty acids distribution and superoxide dismutase activity in lymphocytes of an adult with atypical ceroid lipofuscinosis]. / Anomalies de la répartition des acides gras et de l'activité de la superoxyde dismutase dans les lymphocytes d'un adulte atteint de céroïde - lipofuscinose atypique.

A 27-year-old Algerian patient presented a slowly progressive disease clinically characterized by a cerebellar syndrome, absence of deep reflexes, bilateral sign of Babinski, deep sensory disturbances, ophthalmologic disorders and pes cavus. The diagnosis of ceroid lipofuscinosis resulted from the presence of lipofuscin deposits evidenced as autofluorescent bodies, and a particular type of curvilinear, crystalloid ultrastructural inclusion bodies in muscle, lymphocytes and liver. Biochemical tests showed reduction in levels of linoleic and arachidonic acids, and of superoxide dismutase activity in lymphocytes. These findings suggest that the biochemical anomalies result from disturbances in polyunsaturated fatty acids metabolism. These results can be related to pathogenetic hypotheses for ceroid lipofuscinosis suggesting a predominant role for peroxidation of fatty acids.

[Practical advice concerning biological fluids for analysis of trace-elements]. / Conseils pratiques concernant le recueil des liquides biologiques pour l'analyse des éléments-trace.

Sampling conditions are of utmost importance for the determination of trace elements in biological fluids. However, many biologists still underevaluate this critical step. This reports deals with collection of biological fluids from a routine point of view: detailed and careful descriptions of the contaminating role of air and the general handling of specimens are given in a practical and critical manner. The main commercial systems, made about needles, catheters, tubes (open and evacuated systems) and anticoagulants are reviewed. Choices and elementary rules, applicable in a hospital setting, are proposed.

[Levels of manganese in biological media: value, samplings, physiopathological variations. Bibliographic review]. / Dosage du manganèse dans les milieux biologiques: intérêt, prélèvements, variations physiopathologiques. Revue bibliographique.

The great diversity of methods for manganese analysis in biological materials (serum, plasma, whole blood, urine, spinal fluid and hair) reveals the difficulty in measuring extremely small quantities of this element. An examination of these methods demonstrate that the most used one is flameless atomic absorption spectrometry. This review offers a comparison of the different instrument settings. Authors' recommendations for the collecting of samples are reported in detail. A description of the preliminary steps, the handling of the specimen samples, the preparation of the standards, procedures used, analytical criteria and perturbations is also included. Normal values and their physiological and pathological variations are also described.

[Concentration of zinc, copper, selenium and aluminium in nutritive solutions for parenteral administration]. / Concentration de Zn, Cu, Se et Al dans des solutés nutritifs utilisés par voie parentérale.

Total parenteral nutrition (TNP) therapy is widely used. However the quantitative requirements or the toxicity of trace elements in parenteral solutions are difficult to assess. This paper deals with a study performed by the Trace Element Commission of the Société Française de Biologie Clinique. Trace metals (zinc, copper, selenium and aluminium) which are mainly involved in TPN solutions are analyzed in 12 different parenteral nutrition solutions commercially available. This multicentric assay (5 different sites of analysis) shows that a slight pollution can be noted for nearly all the solutions examined. But at this level (10 mumol/l for the most concentrated solution), the zinc intake cannot induce any toxicity. For copper and selenium the results indicated a negligible pollution. Small-volume solutions added with zinc, copper and selenium are correctly supplemented. As regard aluminium pollution, 4 solutions among 12 contain non negligible amounts of aluminium. The consequences of this TPN overload especially for young infants, indicate that the struggle against this pollution has to be strengthened.

[Determination of trace elements by an assay using flameless atomic absorption spectrometry]. / Mise au point d'un dosage d'élément trace par absorption atomique électrothermique.

The authors review the keys parameters of flameless atomic absorption spectrometry trace element determination in biological medium. Contamination during sample collection and analysis are discussed. Treatments of sample are indicated. The different graphite furnaces are reviewed. Interferences and background correction are discussed. Reference samples are quoted.

[Interlaboratory tests: completion of a method of aluminum assay in serum by electrothermal atomic absorption spectrometry]. / Essais interlaboratoires: mise au point d'une méthode de dosage de l'aluminium dans le sérum par spectrométrie d'absorption atomique électrothermique.

After carrying out a prior analysis of published literature, the members of the SFBC trace-elements study group present an interlaboratory trial on the measurement of aluminum in serum using electrothermal atomic absorption spectrometry. The means of measurement chosen, following methods reliability criteria, was the use of a standard addition calibration of the samples diluted 1/5 in nitric acid 0.02 mol.l-1. Standard addition calibration was performed on two serums and gives acceptable results. Measurements are preferably carried out in 'tantalised' graphite tubes or pyrolytic tubes with platforms. However, when using graphite tubes, their quality must be checked because measurements can be seriously affected by poor quality tubes.

[Determination of proteinuria in children: changes in results according to the methods used (author's transl)]. / Dosage de la protéinurie chez l'enfant. Variabilité des résultats selon la méthode de dosage.

Five methods for determination of proteinuria are compared : gravimetry, colorimetry (bromocresol green, Biuret test, Lowry's test), opacimetry (sulfosalicylic acid). Determinations were performed on normal urine, overloaded with albumin or gammaglobulins or on abnormal urine, after varying several parameters (pH, osmolarity, glucose, fructose, red blood cells, hemoglobin. leukocytes, germs). Some methods give non linear results depending on the concentrations (gravimetry, sulfosalicylic acid, bromocresol green). Some systematically give over-results (Biuret test, Lowry's test). Some almost exclusively determine albumin levels (bromocresol green, sulfosalicylic acid). In some, results are altered by glucose or fructose (Biuret, Lowry) or by red blood cells (Biuret, Lowry, sulfosalicylic acid). None of the tested methods can be used as a reference method. The method using sulfosalicylic acid is suitable for routine determination; however, results should be interpreted according to the parameters mentioned above.

Determination of manganese in biological materials by electrothermal atomic absorption spectrometry: a review.

The great diversity of methods for measuring manganese in biological materials (serum, plasma, whole blood, urine, spinal fluid, and hair) reflects the difficulty in measuring extremely small quantities of this element. Detailed examination of these methods demonstrates that the one most used is flameless atomic absorption spectrometry. In this review we report the different instrument settings for wavelength, slit width, protection gases, graphite furnaces, type of background correction, amounts measured, and thermal programs. We give detailed recommendations by various authors for collecting samples. A thorough description of the preliminary steps and the handling of the specimen samples is also included: direct determination with or without dilution, addition of a matrix modifier or determination after ashing, with or without chelation-extraction steps. The preparation of the standards, procedures used, analytical criteria (accuracy, precision, specificity, detection limit, linearity), problems (interferences, matrix effects), and reference values and their physiological variations are also described. We give a consensus of recommendations concerning the choice of a method.

Sampling conditions for biological fluids for trace elements monitoring in hospital patients: a critical approach.

Lack of coherence in the results of trace element (TE) analyses produced by various laboratories has been such as to necessitate much needed technical improvements and more detailed control over sample preparations. For too long, except for a few praiseworthy researchers, the importance of sampling conditions has been underestimated as a source of erroneous TE results. Many of the precautionary procedures for previously studied TE collection materials have proven to be so cumbersome that they cannot be applied in a hospital setting. This report deals with sampling material and conditions from a workday standpoint; a rigorous description of the contaminating roles of ambient air and routine handling of specimens places emphasis on the practical. While some metals, including cobalt, copper, iron, and selenium, present no significant risk of contamination, others, such as aluminum, cadmium, chromium, manganese, and nickel, pose quite a significant risk. They warrant attention with respect not only to the sampling itself but also the selection of the material to be used. Drawing on our hospital experience, we propose a critical approach toward the collection of samples of biological fluids (blood, urine, dialysis fluids). Needles, catheters, tubes (open and evacuated systems), and anticoagulants on the market are likewise assessed in terms of their contaminative roles. For each one elementary rules as well as realistic choices of materials and methods for a hospital environment are proposed.

[Maternal oligo-elements and fetal malformations]. / Oligo-éléments maternels et malformations foetales.

Serum levels of zinc, copper, manganese, magnesium, folates and vitamin B12 and A, were titrated in the early stage of pregnancy in women who delivered children presenting malformations. These levels were compared with those of control patients who delivered normal children. There were 65 malformations. The most frequent were cardiac, musculo-skeletal, urogenital and chromosomal malformations. Only 2 cases of spina bifida were studied. The oligo-elements and vitamin levels are not different in both groups of women: those who carry malformed fetuses and those carrying normal fetuses. These results are compared with those from the literature.

Glutamic acid decarboxylase in tubules and glomeruli isolated from rat kidney cortex.

4-Aminobutyric acid (GABA) synthesis was examined in purified glomeruli and tubules of rat kidney cortex that were incubated in the presence of [2,3-3H2]glutamate. The GABA that was formed was separated from glutamate using anion-exchange resin, and identified by means of an automatic amino acid analyser. In the renal cortex only the tubules were able to form GABA (35.0 nmol mg-1 h-1); the remaining GABA synthesis found in the glomerular preparations can most probably be attributed to a contamination by cortical tubules (9%), as shown by determination of a known tubular marker enzyme (L-gamma-glutamyltransferase). Hydroxylamine (1 mM) and ethanolamine-O-sulfate (10 mM), well-known inhibitors of cerebral GABA formation and GABA catabolism respectively, inhibited renal tubular GABA formation at 100% and 44% respectively.