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M Delamaire

Publications and source records attributed to M Delamaire.

28 records · Page 2Linked to original sources
PubMed1994

Combined analysis of islet cell antibodies which cross-react with mouse pancreas, antibodies to the M(r) 64,000 islet protein, and antibodies to glutamate decarboxylase in subjects at risk for IDDM.

With regard to progression to diabetes, ICA cross-reactive with mouse pancreas, antibodies to the M(r) 64,000 islet antigen (64K), antibodies immunotrapping brain GAD activity, and IAA were analysed in 53 ICA-positive first-degree relatives of IDDM patients and 18 ICA-positive schoolchildren without a family history of diabetes. Sera from 29 (55%) relatives did not bind to mouse pancreas, whereas 24 (45%) displayed cross-species reaction. ICA titres on human and mouse pancreas were weakly correlated in the overall population (p < 0.05) but more strongly (p < 0.01) in only those subjects who displayed antibodies on tissues from both species. GAD and 64K antibodies were detected in 31% and 35% of relatives. In schoolchildren, the frequencies of cross-species reactive ICA (22%), GAD antibodies (6%), 64K antibodies (22%), and IAA (6%), were lower (p < 0.05) than in relatives. A strong correlation (p < 0.0001) was observed between GAD and 64K antibodies. GAD or 64K antibodies were strongly correlated with ICA on human pancreas (p < 0.0001) but poorly with ICA on mouse pancreas (p = 0.05). After pre-incubation of sera with brain homogenate, ICA titres were unaffected on mouse pancreas but reduced on human pancreas. ICA-positive subjects who displayed neither cross-species reactive ICA nor GAD or 64K antibodies were more frequent (p < 0.05) among schoolchildren than relatives, whereas subjects who displayed all antibody specificities were more numerous (p < 0.04) in relatives. All relatives with ICA binding only to human pancreas, as well as all schoolchildren, permanently displayed an AIRG higher than the first control percentile and remained non-diabetic.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Ex vivo studies of polymorphonuclear neutrophils from patients with early-onset forms of periodontitis. (I). Chemotactic assessment using the under agarose method.

The polymorphonuclear neutrophil (PMN) appears to be an important cell in the protection of the host from pathogenic periodontal microorganisms and, despite some reports to the contrary, it is generally assumed that early-onset forms of periodontal disease (including both juvenile and rapidly progressing periodontitis) are associated with a defect in PMN chemotactic behaviour. The purpose of the present study was to examine the peripheral PMN chemotactic behaviour, using the under agarose method, in 4 groups, namely healthy periodontium group (n = 7), gingivitis group (n = 8), early-onset periodontitis group (n = 17) and adult periodontitis group (n = 8). PMN from early-onset periodontitis patients showed normal random and chemotactic locomotory behaviour when compared with those of PMN from subjects of the other groups. No statistically significant difference could be found among the 4 studied groups, with regard to spontaneous and oriented migration.

Adult↗
PubMed1994

Ex vivo studies of polymorphonuclear neutrophils from patients with early-onset-periodontitis (II). Chemiluminescence response analysis.

Previous studies have indicated that oxygen-free radicals may cause damage to the periodontal tissues. This study compared the luminol-dependent chemiluminescence response (after stimulation with either opsonized zymosan or phorbol myristate acetate (PMA) of peripheral blood polymorphonuclear leukocytes (PMN) isolated from human subjects with a healthy periodontium (n = 7), gingivitis (n = 8), adult periodontitis (n = 8), or early-onset periodontitis (n = 17). These results were also compared with those obtained in a larger reference group which consists of 50 subjects without infection or inflammation, selected on the basis of laboratory investigations. An enhanced response was defined as being 2 standard deviations above the reference group mean; a reduced response was defined as being 2 standard deviations below this mean. Although PMN from patients with either gingivitis or periodontitis were often functionally activated (when compared to the PMN from the reference group), no significant differences could be found between the 4 groups, with regard to the chemiluminescence response means obtained in a basal state or after stimulation.

Adult↗
PubMed1994

Combined analysis of islet cell antibodies that cross-react with mouse pancreas, antibodies to the M(r) 64,000 islet protein, and antibodies to glutamate decarboxylase in type I diabetic patients.

OBJECTIVE: A combined analysis of whether islet cell autoantibodies (ICAs) are cross-reactive with mouse pancreas, with glutamate decarboxylase (GAD) antibodies, and with 64K antibodies was performed in a large sample of recently diagnosed type I diabetic patients. The disappearance rates of these different autoantibodies were compared in some patients after onset of the disease. The aims were to determine patterns in GAD/64K antibodies with regard to cross-species reaction of ICA and to assess whether GAD could contribute to ICA positivity in mouse and human pancreases and whether the simultaneous search for all the antibody specificities enhances the detection of autoimmune stigma. RESEARCH DESIGN AND METHODS: ICA detected by immunofluorescence in human and mouse pancreases, antibodies immunoprecipitating the 64K rat islet antigen, and antibodies immunotrapping brain GAD activity were quantified at diagnosis of diabetes in 95 patients and in sequential samples during 1 year after diagnosis in 13 patients. The contribution of GAD to ICA positivity in mouse and human pancreases was evaluated by the analysis of correlations between tests and by the ability of brain homogenate to block ICA reactivity in pancreases from both species. RESULTS: ICAs were detected in human pancreases in sera from 63 (66%) patients, among which 61% bound also to a mouse pancreas. GAD and 64K antibodies were strongly correlated (P < 0.0001) and were detected in 69 and 73% of the patients, respectively. All but two patients with ICA in human pancreas also displayed either ICA in mouse pancreas or GAD/64K antibodies. Among 32 patients without ICA in human pancreas, 54% displayed either GAD/64K antibodies or ICA in mouse pancreas. Only 16% of the patients displayed neither ICA nor GAD/64K antibodies. A correlation (P < 0.005) was found between ICA in human and mouse pancreases. GAD or 64K antibodies were strongly correlated with ICA in human pancreas (P < 0.0001), but not with ICA in mouse pancreas. After preincubation of six sera with GAD-containing brain homogenate, ICA titers were unaffected in mouse pancreas but reduced in human pancreas. ICA titers in mouse pancreas were decreased after 3 months (P < 0.01) in diabetic patients, contrasting with the stability of ICA in human pancreas and GAD antibodies by 1 year after diagnosis. CONCLUSIONS: According to cross-species reaction, we confirm the heterogeneity of ICA in a large series of type I diabetic patients, ICAs that cross-reacted with mouse pancreas being more frequent than ICAs without cross-species reactivity. GAD and 64K antibodies were also present in a majority of patients. The simultaneous search for all the antibody specificities enhances the detection of autoimmune stigma so that only a few patients did not display any autoantibody at diagnosis. GAD is not the target of ICAs in mouse pancreas, whereas GAD accounts for ICA positivity in human pancreas. The conclusion that ICAs in mouse pancreas are not GAD-reactive is reinforced by the fact that they are more transient after onset of diabetes than are GAD antibodies or the complex mixture of ICAs in human pancreas.

Adolescent↗
PubMed1992

Is there a mechanical factor of haemolysis in patients with positive IgG-type direct antiglobulin test?

In autoimmune haemolytic anaemia, the presence of antibodies on the erythrocyte membrane results in haemolysis through an immune process, but does it not alter the rheological properties of red blood cells (RBC), thus adding a mechanical factor to haemolysis? This study was designed to examine the rheological properties of erythrocytes sensitized with IgG-type antibodies. The study involved 20 patients with anaemia and positive direct antiglobulin test, including 12 with straightforward haemolysis, 10 samples sensitized in vitro, and 20 controls. The following haemorheological parameters were studied: erythrocyte filtration, blood and plasma viscosities, titration of adenosine triphosphate (ATP) and 2-3-DPG, erythrocyte morphology under scanning electron microscopy. The results showed increased erythrocyte rigidity (P less than 0.025) as well as higher blood viscosity compared to controls with similar haematocrit values, and unaltered ATP and 2-3-DPG (consistently with scanning electron microscope observations). These haemorheological disorders were more noticeable in patients with clear-cut haemolysis, and there was a correlation between the increase in erythrocyte rigidity indices and the haemolytic parameters, especially haptoglobin (P less than 0.001). The in vitro study confirmed the results obtained ex vivo. To conclude, the mechanical properties of antibody-coated erythrocytes are impaired, which may promote the immunological mechanism favouring haemolysis in the spleen.

Aged↗
PubMed1991

[Improvement of hemorheologic parameters in hemodialyzed patients treated with human recombinant erythropoietin].

Recombinant human erythropoietin (rhu EPO) is the choice treatment of dialytic anemia; however, this therapy has side effects due to the increased number of blood components involved. It seemed to us worth assessing, by hemorheological study, the impact of such a treatment on blood flow properties, already impaired in this type of patients. This study was designed to measure the evolution of hemorheological parameters in 16 hemodialysed patients before and after 2.3 and 6 months of treatment with rhu EPO. Hemorheological work-ups included: erythrocyte filtration with a hemorheometer; blood and plasma viscosities (LS30), ATP and 2.3 DPG, RBC aggregation (Sefam erythroaggregameter), RBC morphology under a scanning electron microscope; blood counts and full biochemical work-ups were performed to explore renal function. The results showed, besides a significant increase in hemoglobin: normalized rigidity index, reflecting the better deformability of erythrocytes; a moderate increase in blood viscosity with uncorrected hematocrit, becoming significant after 6 months of treatment. This increase however did not reach the values that could be expected with the increased hematocrit (it was probably balanced by improved erythrocyte deformability, which is confirmed by the fact that with corrected hematocrit, blood viscosity decreases during treatment). Studying erythrocyte aggregation in hemodialysed patients reveals, in the absence of any treatment, a decrease in aggregation time and a higher dissociation threshold, which reflects a tendency to erythrocyte hyperaggregation enhanced by erythropoietin.(ABSTRACT TRUNCATED AT 250 WORDS)

Anemia↗
PubMed1990

[Erythrocyte aggregation and vascular pathology].

The aggregation of erythrocytes plays an essential part in vascular diseases involving both the veins and the arteries. In the veins, where the lowest blood flow rates are observed, the conditions of flow foster the aggregation of the erythrocytes, which accounts for blood hyperviscosity that may reinforce the effects of the stasis. In arterial diseases, hyperaggregation of the erythrocytes resulting from risk factors such as smoking, high BP, diabetes, disorders of lipemia, etc. contributes to the formation of stenosis, which has severe consequences for the patient. The prospects of the treatment aimed at correcting the hemorheological disorders caused by hyperaggregation of the platelets are ruled by Poiseuille's formula and based on hemodilution processes and the use of agents lowering fibrinogenemia or molecules improving the forming properties of the red blood cells.

Erythrocyte Aggregation↗
PubMedDate not supplied

Multicenter study of an erythro-aggregometer: quality control and standardization.

There is a need for quality assurance procedures in hemorheology, especially for clinical and pharmacological studies, which require reliable and well-calibrated instruments to be interpretable and comparable. Preliminary investigations allowed preparation of standardized SM (normal NS and hyperaggregable HS), and checking of storage conditions (in accordance with the guidelines of the SSC of ISTH) of RBC in nutritive SAG mannitol for at least 2 or 3 weeks with subsequent washings and resuspension in SM. In our study, we compared erythro-aggregometers of the same brand in 6 laboratories, using the same red blood cells (RBC) and suspending media (SM) for each series of tests. EA was measured by laser backscattering with determination of aggregation time (AT), partial dissociation threshold (PDT) and aggregation index (AI). Prior to the study, devices were set up on the same day with the same standardized blood, and calibration data were then analyzed. Within-assay precision (WAP) was assessed on 3 days for the 2 types of SM (n = 18 x 2). Between-assay precision (BAP) was assessed on 6 occasions, once every month (n = 6 x 2 x 6). Accuracy was studied with 3 series of RBC resuspended in 10 SM of "unknown" aggregability. Good agreement was observed between 5/6 centers for the 3 parameters of EA. WEP was good: CV of AT ranging from 1.4 to 2.5% for the NS and from 1.4 to 2.4% for the HS. In each center, BAP was slightly lower than WEP (CV: 8-11.8% for the NS and 3.8-4.7% for the HS over the 6-month study), with no drift, except for one center. Precision was always better with the HS than with the NS which seemed a better tool to assess it. As to accuracy, non-significant differences were generally found between centers, with similar data to the reference values. This work also stressed the importance of the RBC parameter itself in rheological data. For the first time, a protocol for standardization of EA has been developed and evaluated, permitting the Quality Control of this technique.

Analysis of Variance↗