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Biomedical subjects

O Gaillard

Publications and source records attributed to O Gaillard.

13 recordsLinked to original sources
PubMed1998

Apolipoprotein E and multiple sclerosis: a biochemical and genetic investigation.

Apolipoprotein E (apo E) is postulated to be a major lipid carrier protein in the brain involved in brain development and repair. Multiple sclerosis (MS) is a major demyelinating disease characterized by destruction of myelin and marked alteration of myelin cholesterol and lipid metabolism. We have determined serum and cerebrospinal fluid (CSF) apo E concentrations using an original time-resolved immunofluorometric assay and calculated intrathecal apo E concentration. Apo E concentrations were determined in 13 control subjects and 129 neurological patients: 34 definite MS patients, 25 with Guillain-Barré syndrome (GBS), 32 with amyotrophic lateral sclerosis (ALS) and 38 with other neurological diseases. Seven clinical parameters (sex, age, age at MS onset, duration of the disease, course, clinical status and disability score) were considered in MS patients. Significant (P < 0.01) decrease in CSF apo E was observed in MS, linked to a decrease in intrathecal apo E. The decreased CSF apo E concentration in MS patients occur independent of the apo E genotype. Apo E is considered as a neurotrophic factor in the brain. Any decrease in intrathecal apo E synthesis would thus contribute to progression of neurological diseases, such as MS.

Adult↗
PubMed1995

Decreased cervicovaginal production of both IgA1 and IgA2 subclasses in women with AIDS.

Paired sera and cervicovaginal secretions from 35 HIV-1-infected women representing different CDC stages of HIV infection were evaluated for total IgA, IgA1 and IgA2, for IgA, IgA1 and IgA2 to gp160, and for albumin. Age-matched healthy women (n = 45) served as controls. The secretion rates of total IgA, IgA1 and IgA2 were evaluated by calculating their relative coefficients of excretion by reference to albumin. In HIV-infected women, total IgA1 and IgA2 in sera and in cervicovaginal secretions increased proportionately as early as stages II + III and more markedly at stage IV. By contrast, the secretion rates of total IgA IgA1 and IgA2 were markedly reduced in AIDS women, the IgA2 secretion rate decreasing significantly as early as stages II + III. This apparent discrepancy was probably the result of increased transudation of serum-borne immunoglobulins into the vaginal cavity, since albumin levels in cervicovaginal secretions increased significantly according to the stages of disease. HIV-reactive IgA antibodies in serum, as in cervicovaginal secretions, were principally found within the IgA1 subclass. In women at stage IV, a high local production of IgA1 to gp160 occurred in spite of the impairment of cervicovaginal IgA synthesis, probably because of marked genital HIV replication at advanced stages.

Acquired Immunodeficiency Syndrome↗
PubMed1995

A sensitive time-resolved immunofluorometric assay for the measurement of apolipoprotein B in cerebrospinal fluid. Application to multiple sclerosis and other neurological diseases.

Although low density lipoprotein receptors have been described on oligodendrocytes, apolipoprotein B was thought to be absent or present in only very small amounts in cerebrospinal fluid (CSF). Several immunoassays have been used for the measurement of apolipoprotein B in serum. However, the majority of methods cannot be used to measure small amounts of apolipoprotein B in CSF. In this study, we describe a highly sensitive time resolved immunofluorometric assay (TR-IFMA) using europium as label (detection limit: 0.3 microgram/l). The reliability of the TR-IFMA for the measurement of apolipoprotein B was first studied in serum. Serum and CSF apolipoprotein B concentrations were then determined in subjects free of neurological disorders and in patients with multiple sclerosis. Local intrathecal apolipoprotein B synthesis was calculated. Although the high sensitivity of the TR-IFMA allowed low amounts of apolipoprotein B in CSF to be detected (0.11 +/- 0.06; 0.12 +/- 0.06 mg/l in controls and multiple sclerosis patients, respectively), no apolipoprotein B could be detected in CSF by electroimmunodiffusion. As suggested by the blood/CSF apolipoprotein B ratio (about 6000), no apolipoprotein B synthesis was observed by both using apolipoprotein B index and formula. This indicates its probable serum origin. Moreover, there was no difference between controls and multiple sclerosis patients in CSF, serum, blood/CSF, index, and local intrathecal apoliprotein B synthesis. Finally, these results suggest that the role of apolipoprotein B in lipid transport in the central nervous system may be questionable.

Adult↗
PubMed1994

Immunochemical characterization of monoclonal IgG containing mixed cryoglobulins.

Monoclonal IgG-containing type II cryoglobulins (CG) from 25 patients, most affected with autoimmune or inflammatory diseases, were characterized using a Western blotting procedure. Rheumatoid factors were measured by ELISA. Out of the 25 type II CG, 14 contained a single monoclonal IgG and 11 contained several distinct monoclonal Ig, as assessed by the electrophoretic mobility and isotypy of the narrow bands. Comparison of blots revealed by anti-IgG subclass antibodies in the patients' sera and CG showed a clear-cut enrichment of CG in both polyclonal and monoclonal IgG1 and IgG3. All monoclonal IgG in the CG belonged to the IgG1 or IgG3 subclasses. CG also contained more detectable RF of the IgM class than did the corresponding sera. Using conventional methods, the present CG either could not be typed or were all (immunoelectrophoresis) or often (immunofixation) classified as type III. The results challenge the classical classification of CG and show the necessity of the use of sensitive techniques for immunochemical characterization of mixed CG.

Adult↗
PubMed1994

Electrophoretic study of the physico-chemical characteristics of Bence-Jones proteinuria and its association with kidney damage.

AIM: To identify a physico-chemical criterion, or set of criteria, explaining and possibly predicting the nephrotoxic behaviour of Bence-Jones proteins (BJP). METHODS: The electrophoretic mobility and isoelectric point (pI) of 92 BJP isolates were determined using various electrophoresis procedures on polyacrylamide gel. The proportions of monomers and dimers were determined using sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS PAGE) in 58 cases. PAGE data for 10 BJP isolates were used to construct Ferguson plots and titration curves. RESULTS: The distribution of electrophoretic mobility and pI values was bimodal and showed a positive correlation when the pI was above 6. The values of these two parameters in 22 patients with renal impairment were not significantly different from those in the patients without renal impairment, and the statistical analysis showed no predictive value for the onset of renal impairment. However, patients excreting the lambda light chain isotype had a 2.8-fold higher risk of developing renal impairment compared with the other patients. Studies of the charge variation of the protein with pH indicated three types of behaviour, suggesting that the charge of BJP is highly variable at physiological pH. CONCLUSION: It is important to study not only the positivity or negativity of the BJP charge at a given pH, but also its intensity. The study of the BJP titration curves in patients with renal impairment suggests that a low charge at physiological urinary pH could predict renal impairment.

Aged↗
PubMed1994

[Time-resolved fluorometry: principles and applications in clinical biology].

Time-resolved fluorometric assay is based on lanthanide fluorescence. This time-resolved fluorescence has a narrow-band emission line whose wavelength differs from that of emission-pulsed light and has a long decay-time. These characteristics make it possible to avoid background interference from sample constituents (protein, light-scattering particles, etc). Europium and its chelates are the most commonly used lanthanides. The europium-labelling of antigens or antibodies is followed by immunoassay. In the final step, fluorescence is measured, after enhancement, as counts per second. This assay has several advantages, including a wide working range, high sensitivity and good practicability. The method has widespread applications in the field of immunoassays in both clinical and research laboratories. The use of non-radioactive europium-labelled probes and the development of simultaneous multiple tests are possible future orientations.

Europium↗
PubMed1993

Application of the time-resolved immunofluorometric assay to the study of C3 complement component glycation in vitro and in vivo.

A time-resolved immunofluorometric assay (TR-IFMA) was used for the measurement of glycated C3. The very high sensitivity of this technique allowed the direct measurement of glycated and non-glycated proteins (especially C3) in chromatography eluates. C3 glycation in vitro after incubation with 20 mmol/l glucose was always less than 3.5% by day 5. As determined with the TR-IFMA, the means +/- standard deviations of glycated C3 were 0.20% +/- 0.04 for non-diabetic subjects and 0.88% +/- 0.06 for insulin-dependent diabetic patients. The low percentages of glycated C3 in both our in vitro and in vivo studies show that this protein is subject to only moderate rates of glycation.

Adolescent↗
PubMed1993

Time-resolved immunofluorometric assay of complement C3: application to cerebrospinal fluid.

Complement components have a role in various neurological disorders. Complement C3 can be measured by immunochemical methods, but only radioimmunoassays and electroimmunodiffusion assays (EIDs) are sufficiently sensitive to be applied to biological fluids in which the C3 concentration is low, especially cerebrospinal fluid (CSF). We report a sandwich-type time-resolved immunofluorometric assay (TR-IFMA) for C3 in CSF. The linearity (0.7-3650 micrograms/L) and intra- (CV < 4.8%) and inter-assay (CV < 10.9%) precision were satisfactory and the results agreed with those of EID. The assay is extremely sensitive (< 1 microgram/L) and its analytical range is large and well suited to clinical applications. This simple TR-IFMA is thus a nonisotopic alternative to radioimmunoassay for the quantification of complement C3 in CSF.

Adult↗
PubMed1992

Characterization of cryoglobulins by immunoblotting.

We adapted an immunoblotting technique for the immunochemical characterization of cryoglobulins. We first compared the results from 157 samples with results obtained by immunofixation and immunoelectrophoresis and then with clinical observations in 125 cases. Full identification was possible in 98% of the cases by immunoblotting, in 54% by immunofixation, and in 28% by immunoelectrophoresis. Novel microheterogeneity aspects were observed by immunoblotting and immunofixation in 13% and 6% of the cases studied, respectively. Our results confirm the frequency of autoimmune and infectious diseases associated with mixed cryoglobulinemias, whereas a lymphoproliferative syndrome was observed only in cases of cryoglobulinemia with a monoclonal constituent or a microheterogeneity aspect, which was not always revealed by immunofixation or immunoelectrophoresis. The pathophysiological importance and classification of microheterogeneity aspects is not clear. These observations justify using a sensitive and specific method for identifying cryoglobulins, even when present at low concentrations, and call for long-term studies of these patients.

Autoimmune Diseases↗