Tear analysis as a tool to detect oligoclonal bands in radiologically isolated syndrome.

BACKGROUND: Although radiologically isolated syndrome (RIS) is a newly defined entity, incidental findings of T2 hypersignals on brain MRI can lead to misdiagnosis or useless investigations. The detection of oligoclonal bands (OCBs) in cerebrospinal fluid (CSF) is a major indicator that helps in diagnosis of subclinical inflammatory disease of the central nervous system, but lumbar puncture still remains an invasive option. METHODS: We have prospectively included patients with RIS, have compared the results of CSF and tear OCB detection by isoelectric focusing (IEF) and assessed concordance between OCB detection in tears and in CSF. Tears were collected using a Schirmer strip. RESULTS: In 45 recruited RIS patients, OCBs were detected in CSF for 55% (25/45) and in tears for 50% (21/42) of samples. CONCLUSIONS: We suggest that tear OCB detection may replace CSF OCB detection as a diagnostic tool in patients with RIS and be useful in follow-up.

[Reliability of immunoturbidimetric urine albumin determination for normal and moderately high values]. / Fiabilité du dosage immunoturbidimétrique de l'albumine urinaire pour les valeurs normales ou modérément élevées.

The value of albuminuria determination is commonly accepted in the monitoring of renal function, particularly in diabetic patients. This may be achieved in different ways and using different assay kits. The aim of this study was to assess the reliability of immunoturbidimetric measurements by comparing the results obtained by two different methods in our laboratory. Therefore we measured albuminuria of 54 patients monitored for their diabetes, with normal to moderately high albuminuria, according to two methods: Microalbumin reagent (Beckman Coulter) on a Unicel DxC 600 (Beckman Coulter) and Albumin Turbiquant reagent (Dade Behring, Siemens) on a Turbitimer system (Dade Behring, Siemens). It was then possible to study the correlation between the two techniques. Our results suggest that although this correlation is excellent, the values differ significantly: the results observed with the Siemens method are higher by about 10%. It seems legitimate to think that a correction should be applied, depending on the used method. In addition, it appears that standardization is necessary, concerning analytical stage but although urine collection, pre-analytical stage or reporting and interpretation of results.

Evaluation of semi-automatic image analysis tools for cerebrospinal fluid electrophoresis of IgG oligoclonal bands.

BACKGROUND: IgG concentrations in cerebrospinal fluid generally range from 20 to 45 mg/L. In multiple sclerosis immune reactions lead to intrathecal synthesis of specific IgGs that can be detected in biological fluid samples both quantitatively and qualitatively by isoelectric focusing of supplementary oligoclonal IgG bands. METHOD: A simple tool, using the MATLAB application, to facilitate and improve isoelectric focusing profile analysis is presented and evaluated in terms of its sensitivity, repeatability and reproducibility. A comparison between human readers and semi-automatic method has also been performed. RESULTS: Results from the semi-automatic method were found to be equivalent or superior to generally employed laboratory methods. Repeatability analysis for semi-automatic processing yielded coefficients of variation (CVs) in the 3-7% range, and using a sample with an estimated IgG concentration of 200 mg/L, four bands were still visible after dilution to 5 mg/L, corresponding to band concentrations of 1.1-1.6 mg/L. Discordances between visual inspection and automatic analysis only appear at threshold levels for interpretation (the gray zone). CONCLUSION: The semi-automatic method has acceptable performance for routine implementation.

[Interest of Prom-Test in the follow-up of premature rupture of membranes]. / Place du Prom-Test dans la prise en charge de la rupture prématurée des membranes.

The follow-up of premature rupture of membranes requires an hospitalization. The aim of this work was to evaluate the interest of the Prom-Test in the action to be taken in the case of a suspicion of premature rupture of membranes, a negative result allowing to not hospitalize the patient. 105 tests have been carried out producing 73 negative results, 23 positive and 9 doubtful. The childbirth, started or not, occurred much more quickly when the test is positive. Only 13 of the 73 negative tests resulted in a hospitalization including 11 for beginning of delivery. A correct use of the test can prevent unnecessary days of hospitalization.

[Hyperhomocysteinaemia and type 2 diabetes]. / Hyperhomocystéinémie et diabète de type 2.

OBJECTIVES: Hyperhomocysteinaemia is associated with cardiovascular events in nondiabetic individuals. The present study was aimed to explore the implication of hyperhomocysteinemia in development of cardiovascular events in patients with type 2 diabetes. DESIGN: A total of 185 patients with type 2 diabetes (115 women and 70 men, 30 to 93 years of age) have been included consecutively in the ambulatory unit at the Saint-Philibert Hospital. For each patient the concentration of homocysteine, cholesterol and triglyceride levels and HbA1c have been measured. In the studied population, 121 patients presented cardiovascular events (myocardial infarctus, peripheric arteriopathy, cerebrovascular accident). RESULTS: The patients with cardiovascular events were older, the concentration of homocysteine and creatinine were higher. The plasma homocysteine levels adjusted for age and creatinine levels were higher in patients with cardiovascular events than in patients without cardiovascular events (15.4 +/- 3.52 micromol/L and 13.13 +/- 2.26 micromol/L respectively; p = 2. 10(-5)). CONCLUSIONS: Hyperhomocysteinemia is an independant risk factor for cardiovascular events in type 2 diabetes, independent of age and renal function.

Semi-automated image analysis of gel electrophoresis of cerebrospinal fluid for oligoclonal band detection.

Detection of oligoclonal electrophoretic bands in cerebrospinal fluid (CSF) is an important diagnostic tool for Multiple Sclerosis (MS). Electrophoretic profiles are difficult to interpret due to low contrast and artefacts. A semi-automated method to ease analysis and to reduce subjectivity is presented. The method sequentially converts color images to grayscale, realigns bands, removes artifacts, then converts 2D images to a signal, before detecting, thresholding and editing peaks to optimize profiles. Such treated profiles (21 positive and 15 negative) are compared to ground truth analysis of an expert biologist. 16 profiles over 21 are well detected positive and 12 profiles over 15 are detected negative, results seem similar to inter-experts variability reported in literature.

The MxA protein levels in whole blood lysates of patients with various viral infections.

Interferon alpha (IFNalpha), a type I interferon, can be considered as a viral infection marker because this cytokine is induced during many viral infections. However, it is quite difficult to detect IFNalpha in sera. Investigations are interested in various intra-cellular IFNalpha-induced proteins as viral infection markers. However the activity of these enzymes increased not only in response to type I IFNs but also to type II IFN. MxA protein can be detected in the cytoplasm of IFNalpha/beta-treated cells, whereas other cytokines, including IFNgamma, are poor inducers. Using an immunochemiluminescent assay, we studied MxA protein in whole blood of 34 patients with various viral infections. The whole blood was drawn into sterile vacuum tubes containing heparin or EDTA. MxA values were relatively similar in heparin-treated samples and EDTA-treated samples, with differences not exceeding 1 ng/ml. The levels of MxA protein were compared in whole blood obtained by using two different lysis procedures. A correlation was found between the MxA levels obtained by using procedure I and procedure II, but higher amounts of MxA protein were found with procedure II. The second procedure is rapid and more convenient than the other and it is carried out in one step which reduce technical problems. High levels of MxA protein were found in peripheral blood cells of patients with acute viral infections (Rotavirus, Adenovirus, RSV, CMV), but MxA protein was not elevated in bacterial infections. The MxA levels were also studied in peripheral blood of 32 HCV positive patients. MxA protein was not found in most of IFNalpha-untreated patients, even those with high viral load. In contrast, high levels of MxA protein were found in IFNalpha-treated patients. MxA quantitation can be considered as a specific marker of acute viral infections, and could be useful in the management of treatment with IFNalpha.

Silver stained isoelectrophoresis of tears and cerebrospinal fluid in multiple sclerosis.

Cerebrospinal fluid (CSF) analysis aids in the diagnosis of multiple sclerosis. However, this examination is invasive. The aim of this study was to assess the potentials of a new method of tears isoelectrophoresis (IEF). Silver staining of IEF was used to examined tears and CSF from 123 patients including 60 patients with multiple sclerosis (MS), 50 other neurological patients and 13 patients with inflammatory neurological diseases. Tears were collected on a Shirmer strip placed in one eye, avoiding reflex secretion. This method of IEF with silver staining allowed the detection of oligoclonal bands in tears that were truly immunoglobulin G on immunofixation. The concordance rate between tears and CSF was 83%, meaning that CSF provided no more information than tears analysis in 83% of cases. Sensitivity in tears (72%) and CSF (75%) was very close as was specificity (respectively 84 % and 86 %). High concordance between tears and CSF is the first step in developing a non invasive test which could replace lumbar puncture, particularly when this procedure is not fearalele or is refused by the patient.

Unconjugated pteridines in amniotic fluid during gestation.

Neopterin and biopterin concentrations were measured in amniotic fluid in 226 pregnancies from the 12th week of gestation to term. At mid-gestation, neopterin and biopterin levels were low and remained relatively constant between 12 and 26 weeks of gestation, whereas during the third trimester, a progressive increase was observed. Near term the values were greater than those in maternal serum and the higher neopterin to biopterin ratio suggested that pteridine concentration in amniotic fluid may reflect the maturation of pteridine metabolism in the fetus.

Poisoning with methanol and ethylene glycol:1H NMR spectroscopy as an effective clinical tool for diagnosis and quantification.

Analysis of serum and urine samples from three patients in a metabolic acidotic state was performed using biochemical methods and proton nuclear magnetic resonance (1H NMR). Methanol and ethylene glycol were identified by their singlet peaks in the 1H NMR spectra recorded directly from 0.5 ml of the collected samples. Quantification of these compounds was obtained simultaneously with that of their metabolites, formate and glycolate respectively and of lactate and ethanol, the latter being used as an antidote. The NMR results were found to be very similar to the biochemical findings. The results presented here suggest that 1H NMR can be clinically useful since it quickly provides information on the onset of metabolic acidosis and on the biotransformation of xenobiotics.

[Diagnostic importance of middle latency auditory evoked potentials (MLAEP) in multiple sclerosis]. / Intérêt diagnostique des potentiels évoqués auditifs de latence moyenne (PEALM) dans la sclérose en plaques.

This study was aimed at assessing the interest of middle latency auditory evoked potentials (MLAEP) recordings in multiple sclerosis (MS). Brainstem auditory evoked potentials (BAEP) and MLAEP were recorded in 40 control subjects and 65 patients who had MS according to Poser's criteria. Na and Pa latencies were significantly delayed in the MS group. These abnormalities were detected in 60% of the patients. In 26% of the cases with normal BAEP, abnormalities of MLAEP were present. In 71% of the patients abnormalities of both BAEP and MLAEP were observed. These results suggest the ability of MLAEP recordings to detect lesions of the auditory pathways rostral to the pons and show the value of their combined recordings in MS patients.

[Comparison of spectral analysis and non-linear analysis of EEG in patients with cognitive decline]. / Comparaison de l'analyse spectrale et de l'analyse non-linéaire de l'EEG dans les troubles cognitifs.

Twenty-five elder subjects were classified in two groups according to the MMS score and the cognitive evoked potentials. Normal subjects (n = 15) had mean MMS = 27.6 and mean P3 amplitude = 7.1 uV), while patients with cognitive decline (n = 10) had respective values of 18 (MMS) and 3.3 uV (P3). Spectral analysis and non-linear analysis of EEG (recurrence plots of dynamical systems) were performed and both showed statistically significant differences between groups for all the parameters analysed. Subjects' classification with discriminant analysis was slightly better using the non-linear parameters. The recurrence plot method applied to EEGs, gave similar results as the dimension of correlation (D2) calculation, and was in favour of a more constraint and less complex dynamics of brain activity associated with cognitive decline.

Variations of IL2, IL6, TNF alpha plasmatic levels in relapsing remitting multiple sclerosis.

We performed a longitudinal analysis of serum IL2, IL6 and TNF alpha concentrations in 40 relapsing remitting MS patients and 20 healthy subjects. Disease activity was quantified by Minimal Record of Disease (M.R.D.) for MS, every 2 or 3 months. IL2, IL6 TNF alpha production was analysed without and with PHA stimulation of whole blood for 2 hours at 37 degrees C. No significant change in IL2 level was found in MS serum. Individual TNF alpha production was significantly increased (P < 0.007) during relapses. The global spontaneous IL6 production was markedly higher in the relapse group than in the control group (P < 0.01) and than in the remission group (P < 0.002) without significant individual variations of cytokine levels regarding the disease activity. Productions of cytokines were enhanced by PHA stimulation, a condition that however suppressed the differences observed without mitogen stimulation. Our data suggest that TNF alpha could be a marker for relapses while IL6 might reflect the global activity of the immune system in MS.

[Prevalence of hepatitis C, B and D markers and histopathological aspects in a group of intravenous drug addicts]. / Prévalence des marqueurs des hépatites C, B et D et aspects histopathologiques dans un groupe de toxicomanes intraveineux.

OBJECTIVES: The aim of this study was to assess the prevalence of infection by HCV, HBV, HDV and HIV and their biological and histopathological patterns in 104 intravenous drug users. METHODS AND RESULTS: Seventy-five patients (72%) had anti-HCV antibodies. Transmission was rapid because 33% of those who had been drug users for 6 months or less had anti-HCV antibodies. The contamination rate was very high because 90% of those who had been drug users for 2 years or less had anti-HCV antibodies. Thirty-four (33%) had an HBV marker, and 6 were HBs Ag carriers. None of the patients had anti-HDV antibodies. Only one patient had anti-HIV antibodies. Twenty-five anti-HCV antibody positive drug users underwent liver biopsy. Seven (28%) had normal ALAT levels and 18 (72%) had permanently or intermittently elevated ALAT levels. The mean histological activity on the Knodell index was 4.1 (range: 1-8). CONCLUSIONS: This study indicates that contamination by HCV is almost inevitable after 2 years of intravenous drug use. The low prevalence of HBV, HDV, and HIV infection might be explained by a low endemic state of these viruses in our area.

[Visual evoked potentials and face recognition. Influence of celebrity and emotional expression]. / Potentiels évoqués visuels et reconnaissance des visages: influence de la célébrité et de l'expression émotionnelle.

Visual evoked potentials (VEP) were recorded in the right and left parietal and occipital regions of 40 right-handed controls in a facial recognition task. VEP were studied first according to the renown of the faces, then according to their emotional expression. Asymmetry was noted between the hemispheres: P100 was of greater amplitude and longer latency in the left occipital region. Later components (P400 and P600) were of greater amplitude and longer latency in the right parietal region in all situations. P100 latency on the left side was shorter for renowned faces than for non-renowned faces (P = 0.05). P600 latency was shorter on the right (P < 0.03) and left (P < 0.05) sides for smiling than for non-smiling faces. When the subjects were asked to look for emotional expression of the face (smiling or non-smiling) P400 was very ample and P600 of little amplitude. When the subjects were asked to recognize the face (renowned or not renowned) P600 was very ample and P400 of little amplitude. Thus, there seems to be a differential treatment of information: automatic and rapid to detect emotion (P400), controlled, tardy (P600) and involving memory in the search for renown.

[Late auditory evoked potentials in subcortical cognitive deterioration]. / Potentiels évoqués auditifs tardifs dans les détériorations cognitives sous-corticales.

Late auditory evoked potentials (AEPs) were recorded by the odd-ball method in 55 non-deteriorated parkinsonians (NP) and in 27 parkinsonians with cognitive deterioration (CDP), compared with 20 controls (C) and 24 patients with Alzheimer-type senile dementia (ATSD). The latency of P 300 was prolonged in the CDP and ATSD groups (410.72 +/- 24.45 and 433.62 +/- 38.30 respectively; P less than 0.001. The latency of N 100 was prolonged only in the CDP group (106.6 +/- 4.82; P less than 0.001). Late AEPs were also studied in 63 subjects with possible or confirmed disseminated sclerosis (DS) compared with 33 controls of similar mean age. The ERFC test divided these patients into 38 with non-deteriorated DS (NDS) and 25 with deteriorated DS (DDS). The latency of P 300 was prolonged in both groups: NDS 331.14 +/- 25.89; DDS 376.64 +/- 29.51 (P less than 0.001). The latency of N 100 was prolonged in the NDS group (100.25 +/- 9.20) and the DDS group (104.43 +/- 9.01). Following a study of correlations between the degree of mental deterioration and the electrophysiological parameters in these populations, the significance of the N 100 latency as electrophysiological marker of subcortical dementia is discussed.

[Unconjugated pteridines and neuromeningeal infections]. / Ptéridines non conjuguées et infections neuro-méningées.

Concentrations of unconjugated pteridines (neopterin, monapterin, biopterin, pterin) were measured in the cerebrospinal fluid (CSF) of 310 patients, using a high performance liquid chromatography (HPCL) method. Our cohort included 209 controls (C), 15 patients with meningism (M), 22 with viral meningitis (VM), 17 with bacterial meningitis (BM), 9 with herpetic meningoencephalitis (HME), 2 with tuberculous meningoencephalitis (TME) and 36 with peripheral systemic infections (PI). These measurements, expressed as nmol/litre, showed a gradation of neopterin concentrations according to the type of infection: 20.1 + 6.5 in group C; 46.9 +/- 29.9 in group PI; 274.3 +/- 231.7 in group VM; 699.2 +/- 711.2 in group BM, 1,101.9 +/- 1,107.9 in group HME and 1,169 +/- 1,171.9 in group TME. There was no such gradation with biopterin. Comparisons of means showed that total concentrations in the pathology groups were very different from those observed in controls and in the neuromeningeal infections of the PI group. There was no correlation between the number of lymphocytes and the concentrations of neopterin or biopterin in the CSF. It is concluded that the concentration of neopterin in the CSF is a sensitive but little specific marker of infection, independent of CSF cellular reaction. Measuring this concentration makes it possible: 1) to evaluate the status of immune defences; 2) to predict that a meningitis will become chronic, and 3) to detect a possible parenchymal participation in a meningeal infection.

[Usual values for 5-hydroxy-indol acetic acid and homovanillic acid in cerebrospinal fluid]. / Etablissement de valeurs usuelles pour les acides 5-hydroxyindolacétique et homovanilliquedans le liquide céphalorachidien.

The aim of this work was to reinvestiagte usual values of neurotransmitter catabolites (5-HIAA and HVA) in CSF, their determination being a current method for studying pathological processes and/or drug induced changes on CNS metabolism. 5-HIAA and HVA have been measured by reverse phase HPLC and electrochemical detection. Since many confounding factors have been identified to modify the concentration of both analytes in CSF, data from 1.480 patients have been revisited with strict exclusion and 323 have been selected. Age dependent variation and asymetric distributions were observed. Age-related usual values ranges were established after identification of outliers by non-parametric analysis. In a group of patients for which repeated CSF collection have been performed for the follow up of acute leukemia, wide and unpredictible individual variations (up to 400 %) of CSF 5-HIAA and HVA concentrations have been observed. These large interindividual and individual variations may explain the numerous discrepancies found in studies investigating the CNS monoamine metabolism, especially when small groups of patients are used. Such observation limits the interpretation of monoamine metabolic for diagnostic purposes without a strict selection of indication.

[Use of formulas for calculating serum osmolality]. / De l'usage des formules de calcul de l'osmolalité sérique.

Osmolality can be measured or calculated. More than ten formulas have been proposed for calculating serum osmolality from chemical concentrations. The aim of this work was to compare results obtained whith some of these formulas, those calculated in the laboratory using a multiple regression model and measurements with an osmometer. Scattered results for natremia and chloremia, depending on the automate, led us to define formulas adapted for each measurement system in order to reduce the risk of error in the evaluation of the " osmolar gap ".

[Comparison of 11 electrochemical detectors used in high performance liquid chromatography]. / Comparaison de onze détecteurs électrochimiques utilisés en chromatographie liquide haute performance.

Electrochemical detection is more and more frequently used in clinical chemistry. The performances of eleven detectors (sensitivity stability, limit of detection, figure of merit) have been compared. There is a large variation in results for sensitivity and figure of merit, but all of these detectors seem stable and reproducible.