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Biomedical subjects

A Goguel

Publications and source records attributed to A Goguel.

At least 19 recordsLinked to original sources
PubMed2001

Flow cytometric analysis of inflammatory markers in KCS: 6-month treatment with topical cyclosporin A.

PURPOSE: Immune-based inflammation has been observed as a common mechanism of keratoconjunctivitis sicca (KCS). In KCS-affected eyes, upregulated expression of HLA DR and various immune- or apoptosis-related markers by conjunctival epithelial cells has been demonstrated in an earlier study, by a technique of flow cytometry in impression cytology (IC) specimens. The purpose of this study was to monitor the effects of topical cyclosporin A on the expression of these markers throughout a 6-month period of treatment. METHODS: Patients with moderate to severe KCS included in a large European multicenter clinical trial (Cyclosporin Dry Eye Study, Allergan, Irvine, CA) underwent collection of IC specimens at baseline, month 3, and month 6. For 6 months, they randomly received 0.05% or 0.1% cyclosporin A or vehicle. Specimens were processed and analyzed in a masked manner by flow cytometry, using monoclonal antibodies directed to HLA DR, CD40, CD40 ligand, Fas, and the apoptotic marker APO2.7. Percentages of positive cells were calculated and levels of expression quantified after conversion into standardized units of fluorescence. RESULTS: One hundred fifty-eight patients had at least two IC specimens available for flow cytometry analysis. HLA DR expression, both in percentage of positive cells and level of expression, was highly significantly reduced after 0.05% and 0.1% cyclosporin A treatment at months 3 and 6 compared with baseline values, whereas vehicle did not induce any change in HLA DR expression over time. The 0.05% and 0.1% cyclosporin emulsions were significantly more effective than the vehicle in reducing HLA DR at months 3 and 6 (0.05%), and at month 6 (0.1%). CD40 expression was significantly reduced at month 3 and partially at month 6, compared with baseline, with no reduction in patients who received the vehicle. CD40 ligand expression also decreased at months 3 and 6 in patients taking both concentrations of cyclosporin A. APO2.7 expression was significantly increased in all three groups, whereas percentage of Fas-positive cells decreased only in patients treated with 0.05% cyclosporin A at months 3 and 6. CONCLUSIONS: Flow cytometry provided an objective technique to monitor the effects of topical cyclosporin A on immune- and apoptosis-related markers in the conjunctival epithelium of patients with KCS enrolled in a large multicenter trial. Topical cyclosporin A strikingly reduced HLA DR and to a lesser extent, other inflammatory and apoptotic markers, whereas the vehicle, used as a control tear substitute, had almost no effect. This study confirms that cyclosporin A may be efficient in reducing conjunctival inflammation in moderate to severe KCS and is consistent with clinical results in this indication.

Administration, Topical↗
PubMed2000

Correlation between tear IgE levels and HLA-DR expression by conjunctival cells in allergic and nonallergic chronic conjunctivitis.

BACKGROUND: Chronic conjunctival inflammatory diseases may depend upon various mechanisms. Discriminating allergy from nonspecific inflammation has become of striking importance for diagnosis and treatment. We investigated conjunctival inflammatory response by comparing two objective biological tools, tear IgE and HLA-DR expression by conjunctival epithelium, as indirect indicators of activation of the Th2 and Th1 subsets, respectively. METHODS: Eighty-two patients with chronic conjunctivitis underwent tear IgE measurement by an ELISA technique and quantitation of HLA-DR expression in impression cytology specimens. Forty-two had direct or indirect clinical indications of allergic mechanisms, 26 had chronic conjunctivitis without any sign of allergy, and 14 suffered from isolated nonallergic dry eyes. RESULTS: Patients clinically considered as allergic only showed positive IgE in 47 of 84 eyes (56%), whereas 21% and 25% of eyes with nonspecific conjunctivitis and dry eyes respectively were also positive. IgE levels were significantly higher in the allergic group than in the other two groups. HLA-DR positivity in epithelial cells was found in 28.5%, 48% and 50% of eyes, respectively. HLA-DR expression by epithelial cells was negatively correlated with tear IgE, as most specimens positive to one criterion were negative to the other one (49 eyes DR+, IgE-; 47 eyes DR-, IgE+; only 9 eyes positive to both criteria; chi-square: P = 0.0001). CONCLUSION: As IgE synthesis and HLA-DR induction may represent indirect indicators of the activation of the Th2 and Th1 subsets, association of these two simple tests could be interesting for the routine assessment of the mechanisms of inflammatory ocular surface diseases.

Adolescent↗
PubMed2000

Expression of CD40 and CD40 ligand in the human conjunctival epithelium.

PURPOSE: CD40 antigen is a membrane receptor that plays a role in the regulation of immune reactions. The expressions of CD40 and CD40 ligand (CD40L) were investigated ex vivo and in vitro in conjunctival epithelial cells, in correlation with HLA DR class H antigen, previously shown to be upregulated in conjunctival inflammatory conditions. METHODS: Impression cytology specimens were collected in 186 patients: 52 normal ones, 65 with keratoconjunctivitis sicca, and 69 with chronic conjunctivitis. Cells were processed for flow cytometry, by using monoclonal antibodies to CD40, CD40L, and HLA DR antigens. Chang conjunctival cells were also used and treated with human recombinant interferon (IFN)-gamma or tumor necrosis factor (TNF)-alpha. CD40, CD40L, and HLA DR expressions were studied by flow cytometry after 24 and 48 hours of treatment. RESULTS: CD40 was found in both normal and pathologic eyes. Quantitation of levels of fluorescence showed a significantly higher expression in pathologic eyes than in normal ones (P < 0.0001). CD40L was variably and inconstantly expressed by conjunctival cells. A strong expression of HLA DR was observed in pathologic eyes, whereas normal eyes showed very low levels (P < 0.0001). Significantly positive correlations were found among CD40, CD40L, and HLA DR levels. Chang conjunctival cells expressed CD40 in basal conditions, whereas CD40L and HLA DR were negative. CD40 expression significantly increased after 24 hours of IFNgamma treatment and after 48 hours' exposure to TNFalpha. These cytokines had no effect on CD40L expression. HLA DR was upregulated after 24 hours of treatment with IFNgamma but remained negative after exposure to TNFalpha. CONCLUSIONS: Human conjunctival epithelial cells normally express CD40 antigen, and, more inconsistently, CD40L. Flow cytometry showed higher expression of these molecules in inflammatory eyes than in normal ones in correlation with class II antigen expression, as well as CD40 and HLA DR upregulation after treatment with proinflammatory cytokines in vitro.

Adult↗
PubMed2000

Flow cytometric analysis of inflammatory markers in conjunctival epithelial cells of patients with dry eyes.

PURPOSE: To investigate in impression cytology (IC) specimens the expression of inflammatory and apoptosis-related markers by conjunctival epithelial cells from patients with dry eye as a rationale for treatment with topical cyclosporine. METHODS: Immunologic anomalies were identified at baseline, before treatment with the masked medication, in a homogeneous series of patients with dry eye syndrome, who were enrolled in a large European multicenter clinical trial (Cyclosporin A Dry Eye Study; Allergan, Irvine, CA). IC specimens were collected in 243 patients with moderate to severe keratoconjunctivitis sicca (KCS), with or without Sjogren's syndrome (SS). Fifty normal subjects were separately examined to provide normal control values. Specimens were analyzed in a masked manner by flow cytometry, using antibodies directed to markers of the immune system and/or apoptotic pathway: HLA DR, CD40, CD40 ligand, Fas, and APO2.7. Levels of expression were quantified, and results were compared with those obtained in the 50 normal patients. RESULTS: One hundred sixty-nine specimens were successfully interpreted at baseline, including 41% from patients with SS. A highly significant increase of HLA DR expression by conjunctival cells was found in KCS-affected eyes compared with normal eyes, which did not express this marker or did so very weakly. HLA DR expression in eyes with SS was significantly higher than in KCS-affected eyes without SS. Fas and APO2.7 were found at low levels in all normal and KCS-affected eyes. CD40 and CD40 ligand expressions were significantly increased in eyes with KCS compared with normal eyes. HLA DR, CD40 and Fas were found at significantly higher levels in the SS group than in the non-SS group. CONCLUSIONS. Conjunctival cells from patients with dry eye with moderate to severe KCS, with or without SS, overexpress inflammatory and apoptosis-related markers. Whether inflammation is a primary phenomenon in KCS or is the consequence of repetitive abrasion of the ocular surface after tear film deficiency remains to be determined. These data, nevertheless, support the use of immunomodulatory and/or anti-inflammatory drugs in the treatment of patients with KCS.

Adolescent↗
PubMed1999

Multicenter study of reference stabilized human blood for lymphocyte immunophenotyping quality control in flow cytometry. GEIL.

The development of automated methods and normative rules, as well as the dependence of some therapeutic approaches on lymphocyte subsets counts, has led to the appearance of calibration reagents. Such reagents are expected to perform equally well in very different settings. We developed a multicenter trial to evaluate the performance of a new quality control reagent, i.e., stabilized blood to be used in immunophenotyping laboratories. Aliquots of the same batch of stabilized blood were shipped to 45 French and Belgian laboratories on a Monday and had to be tested for percentages and absolute counts of at least CD3-, CD4-, and CD8-positive lymphocytes on 4 consecutive days. The percentages and absolute counts obtained on each assay were recorded, as well as the type of lysis used, the trademark of reagents, and the brand of flow cytometer. The mean values collected did not differ significantly from those expected by the manufacturer. Absolute counts generated through one-step techniques displayed lower CVs. This new reagent therefore appears to be a robust product, liable to yield consistent results in the array of different conditions represented by routine laboratories, and it could be useful for quality control procedures.

Flow Cytometry↗
PubMed1999

Interferon-gamma induces apoptosis and expression of inflammation-related proteins in Chang conjunctival cells.

PURPOSE: The purpose of this study was to investigate the effect of interferon (IFN)gamma on cell viability, cell growth, and apoptosis and on expression of apoptotic and inflammation-related proteins in epithelial conjunctival cells in vitro. Some aspects of transduction pathways of IFNgamma-induced alterations were also investigated, especially the role of protein kinase C (PKC) and IFNgamma transcriptional factor STAT1. METHODS: A human conjunctival cell line was treated with different concentrations (30 and 300 U/ml) of human recombinant IFNgamma. After 24, 48, and 72 hours of treatment, cell viability and relative cell number were studied with 3-(4,5-dimethylthiazol-2yl)2,5-diphenyl tetrazolium bromide (MTT) and crystal violet colorimetric assays. The apoptotic process was sought by phase-contrast microscopy, 4',6'-diamidino-2-phenylindole dihydrochloride (DAPI) staining, and transmission electron microscopy and was confirmed by DNA electrophoresis and immunoblotting of poly(ADP-ribose) polymerase (PARP). The cell cycle and expression of apoptotic proteins Fas, bax, and p53; of inflammation-related proteins HLA-DR and intercellular adhesion molecule (ICAM)-1; and of IFNgamma signal-transducing factor STAT1 were evaluated by flow cytometry and/or western blot analysis. To investigate PKC-related transduction pathways, two PKC modulators, 12-O-tetradecanoyl-phorbol-13-acetate (TPA) and staurosporine, were applied for 3 hours, followed by IFNgamma treatment for 72 hours. Moreover, the effects of PKC depletion were studied after a 24-hour application of TPA, also followed by IFNgamma treatment for 72 hours. Then, Fas, ICAM-1, and HLA-DR expressions were studied by flow cytometry. RESULTS: IFNgamma at 30 U/ml induced no change in cell cycle and in cell viability. Cell viability significantly decreased after 48 hours of treatment with 300 U/ml IFNgamma, associated with cell cycle alterations (decrease in number of cells in the S-M phase), apoptotic chromatin condensation and fragmentation, ladder pattern on DNA electrophoresis assay, and cleavage of PARP. Moreover, IFNgamma-treated cells overexpressed plasma membrane Fas, HLA-DR, and ICAM-1 in a dose- and time-dependent manner, and STAT1 in both nuclear and cytosolic cell fractions. Only 300 U/ml IFNgamma-treated cells overexpressed bax, whereas Bcl-2 and p53 proteins were not modified. HLA-DR and Fas were upregulated after addition of staurosporine or after PKC-depleting treatment and repressed with TPA. Staurosporine, PKC depletion, and TPA all enhanced ICAM-1 expression. CONCLUSIONS: In our model, IFNgamma induced expression of inflammatory molecules and apoptotic mediators, cell growth arrest, and apoptosis of Chang conjunctival cells. Moreover, our results suggest that activation of PKC is not involved in some IFNgamma cellular effects that possibly imply the upregulation and nuclear translocation of STAT1. IFNgamma-induced apoptosis could explain in part the recently reported coexistence of inflammation and programmed cell death in ocular surface inflammatory disorders such as Sjögren's syndrome.

Apoptosis↗
PubMed1998

Expression of Fas-Fas ligand antigens and apoptotic marker APO2.7 by the human conjunctival epithelium. Positive correlation with class II HLA DR expression in inflammatory ocular surface disorders.

Fas antigen (CD95) is a membrane receptor that plays a major role in induction of apoptosis. In surface conjunctival epithelial cells the expressions of Fas, Fas ligand, the apoptotic marker APO2.7 and of HLA DR class II antigen, a membrane marker known to be expressed in inflammatory conditions were investigated. Impression cytology specimens were collected in 65 patients: 20 normal ones, 15 contact lens wearers, 20 receiving chronic topical antiglaucoma treatment and 10 with nonspecific chronic conjunctivitis. Cells were processed for flow cytometry, using monoclonal antibodies to Fas, Fas ligand, APO2.7, HLA DR antigens and a negative isotypic control. Percentages of positive cells were recorded and levels of fluorescence quantified using fluorescent beads at standardized fluorescence intensities. In addition, a human conjunctival cell line was incubated with anti-Fas stimulating antibodies in order to test Fas-induced apoptosis in vitro. Fas was found in all specimens in most of the conjunctival cells, but quantitation of levels of fluorescence showed a significantly higher expression in pathologic eyes than in normal ones. Fas ligand and APO2.7 were variably expressed by conjunctival cells, but in a significantly higher percentage of cells in pathological eyes than in normal ones. In these eyes a strong expression of HLA DR was also observed, whereas normal eyes showed lowest levels. Highly significant correlations were found between Fas, Fas ligand, APO2.7 and HLA DR levels. Anti-Fas antibodies in vitro induced strong apoptosis in epithelial cells as confirmed by APO2.7 expression and DAPI staining. This study confirms that conjunctival epithelial cells normally express Fas antigen, and more inconstantly its ligand, as do corneal ones or keratinocytes. Fluorescence quantitation by flow cytometry showed much higher expression in inflammatory eyes than in normal ones, and demonstrated a strong correlation between apoptotic and inflammatory pathways in the ocular surface.

Adult↗
PubMed1998

[Treatment of polycythemia. I--Using radiophosphorus with or without treatment in 483 patients over 65 years of age].

AIMS: To compare by a prospective study in high risk polycythemia vera (PV) patients 33P alone and 32P followed by low-dose hydroxyurea (HU) maintenance therapy. Toxicity, efficiency, and leukemogenic potential were studied. PATIENTS: 483 patients with a documented PV, aged more than 65 years at diagnosis, were included between 1980 and 1996 in a prospective study comparing 32P alone and 32P followed by low-dose HU maintenance therapy. Blood cell counts were performed every two months and a clinical evaluation by a specialist was obtained every four or six months. RESULTS: Treatments were well tolerated, but chronic leg ulcers were observed in the maintenance therapy arm. The risk of leukemia was about 15% at the 15th year in the group of patients treated by 32P alone, but reached 30% in the group receiving maintenance therapy. In both arms, there was no significant correlation between occurrence of leukemia and the total dose of 32P. There was a correlation between the leukemic risk and disease severity, estimated on the frequency of relapse. Cancer occurrence was slightly higher than expected in the maintenance arm. HU treatment did not protect against progression to myelofibrosis, probably due to the lack of maintenance of an efficient myeloid or megakaryocytic suppression. Median life-span was slightly shorter in the group receiving HU maintenance. In all cases, life-span was only one year lower than that observed in the reference population. CONCLUSION: For all these reasons, we suggest the us of 32P alone in elderly patients; complementary chemotherapy should only be prescribed in the cases with short-term relapse, and late resistance to 32P.

Aged↗
PubMed1998

[Value of lacrymal IgE determination and conjunctival cytology in the diagnosis of chronic conjunctivitis].

PURPOSE: Chronic conjunctival inflammatory diseases may depend upon various strongly intricated mechanisms. Discriminating allergy from nonspecific inflammation has become of striking importance for diagnosis and treatment. We investigated conjunctival inflammatory response by comparing two objective biological tools, tear IgE detection and HLA DR expression by conjunctival epithelium, as indirect indicators of activation of the Th1 and Th2 subsets, respectively. METHODS: Sixty-eight patients (135 eyes) with chronic conjunctivitis underwent tear IgE dosage by an ELISA technique and quantification of HLA DR expression in impression cytology specimens. 34 had direct or indirect clinical indications of allergic mechanisms, 22 had chronic conjunctivitis without any sign of allergy, and 12 suffered from isolated nonallergic dry eyes. RESULTS: Patients clinically considered as allergic only showed positive IgE in 31 out pf 68 eyes (46 per cent), whereas 11/44 (25%) and 7/24 (29%) eyes with nonspecific conjunctivitis and dry eyes respectively were also positive. HLA DR positivity in epithelial cells was found in 18/61 (29.5%), 15/40 (37.5%) and 9/22 (41%) eyes, respectively. HLA DR expression by epithelial cells was negatively correlated with tear IgE, as most specimens positive to one criterion were negative to the other one (37 eyes DR+ IgE-, 35 eyes DR- IgE+, and 5 eyes DR+ IgE+; chi-square: p = 0.0001). CONCLUSION: As IgE synthesis and HLA DR induction may represent indirect indicators of the activation of the Th1 and Th2 subsets, association of these two simple tests could be interesting for the routine assessment of the mechanisms of inflammatory ocular surface diseases.

Adult↗
PubMed1997

PMA induces platelet activation of specific antigens (CD62/CD63) in GpIIb-IIIa deficient platelets from Glanzmann's thrombasthenia.

Glanzmann's thrombasthenia (GT) is a hereditary platelet disorder resulting from a quantitative or qualitative deficiency of the major platelet membrane complex GPIIb-IIIa (CD41) required for platelet aggregation. We investigated by flow cytometry, the expression of CD41, fibrinogen, and of two platelet activation-related antigens, CD62 and CD63, (i) before and after activation of platelets by PMA, and (ii) on the surface and within the cytoplasm of resting platelets, after permeabilization by saponin. Platelets from a series of normal subjects and from nine members of two GT families, were reacted with FITC-conjugated antibodies and analyzed on a flow cytometer. Fluorescence intensities measured on normal and GT platelets were quantified by using calibrated beads. Results showed lack of both GPIIb-IIIa and fibrinogen, on the platelet surface and also within the cytoplasm in five of these GT patients, whereas GPIIb-IIIa and fibrinogen remained normal in the four other cases. However, CD62 and CD63 antigenic levels were found within normal range for all members of these families, after PMA stimulation and also after platelet permeabilization. This work therefore showed that the lack of CD41 in GT, which causes strong disturbance of platelet aggregation, may not be associated with the deficiency of activation pathways.

Journal Article↗
PubMed1997

Flow cytometry in impression cytology specimens. A new method for evaluation of conjunctival inflammation.

PURPOSE: To investigate feasibility and potential uses of flow cytometry in impression cytology as a new procedure to assess and quantify conjunctival inflammation. METHODS: Specimens for cytology were collected by impression from 30 patients with various chronic ocular surface disorders and from 10 normal subjects. Two specimens were obtained in each eye: One was transferred onto a glass slide and processed by immunofluorescence with antibodies to human leukocyte antigen (HLA)-DR antigens; cells from the other were suspended in phosphate-buffered saline for flow cytometry. Monoclonal antibodies to HLA-DR antigens and CD23, the low affinity receptor to immunoglobulin E, were used. RESULTS: Abnormal expression of HLA-DR and CD23 by conjunctival cells was found in 13 of 18 dry eyes and in 20 of 22 eyes with chronic conjunctivitis, whereas specimens remained almost negative (less than 10% of cells were positive) in normal eyes. Percentages of positive cells ranged between 20% and 98% of all conjunctival cells. Correlation between the two methods, immunocytology and flow cytometry, was highly significant (coefficient of correlation 0.77, P = 0.0001). Moreover, HLA-DR positivity, at its strongest intensity, was observed in a minority of cells (1% to 12%), most of which were resident class II-expressing dendritic cells. Percentages of those cells expressing high levels of HLA-DR were 3 +/- 1.2% in normal eyes, 5.8 +/- 4% in dry eyes (P = 0.05), and 5.9 +/- 3.5% in eyes with chronic conjunctivitis (P = 0.02). CONCLUSIONS: Results of this preliminary study confirm that conjunctival epithelial cells may abnormally express inflammatory markers in chronic ocular surface disorders. Development of flow cytometry in analysis of cytologic specimens provides a new, sensitive, and objective tool for exploring conjunctival pathology.

Antibodies, Monoclonal↗
PubMed1996

Lupus anticoagulants: first French interlaboratory Etalonorme survey.

In 1994, the, French National Quality Control Group for Hematology, Etalonorme, conducted a large-scale interlaboratory survey concerning the detection of lupus anticoagulants (LA) involving all the 4,500 French laboratories. Each laboratory received the same batch of a lyophilized citrated plasma (94B3) prepared from a patient with LA that had been confirmed by all the techniques used in the intralaboratory study. In the interlaboratory survey, the screening test was activated partial thromboplastin time (APTT); mean APTT calculated from the results reported by 4,029 labs was prolonged (clotting ratio = 1.44) with a large dispersion (coefficients of variation = 18.8%). APTT of the mixture 94B3 + normal plasma were performed by 2,698 laboratories. No correction of APTT was obtained (R = 1.36, Rosner index = 24) with a wide variation between reagents (17 < Rosner index < 39). Only 15% of the participants performed confirmatory tests; dilute tissue thromboplastin inhibition test (TTI) performed by 509 laboratories gave 75% positive results. Tests with an increased amount of phospholipids (Staclot LA and Staclot PNP from Diagnostica Stago), used by 116 and 72 laboratories, gave 88% and 61% positive results, respectively. A total of 1,862 laboratories made the diagnosis of LA. The majority of those who failed in diagnosing LA used an APTT reagent largely used in France, containing kaolin. This survey allowed Etalonorme to inform French biologists and draft an educational program for the biologic detection of LA and the identification of its mechanism of action.

France↗
PubMed1996

Risk of leukaemia, carcinoma, and myelofibrosis in 32P- or chemotherapy-treated patients with polycythaemia vera: a prospective analysis of 682 cases. The "French Cooperative Group for the Study of Polycythaemias".

An analysis of the risk of progression towards leukemia, carcinoma and myelofibrosis was performed in 93 patients treated by 32P alone (PVSG protocols) since 1970-1979, 395 patients over the age of 65 years treated by 32P with or without maintenance therapy using hydroxyurea (French protocol) since 1980-1994, and 202 patients under the age of 65 treated by either hydroxyurea or pipobroman since 1980. The risk of leukemia, or myelodysplasia, or lymphoma in the 32P-treated patients was 10% at the 10th year, but increase after that time to reach a value of about 30% at the 20th year, in the surviving case. This risk was not dose-related. Despite a marked reduction of the cumulative 32P dose in the patients maintained by hydroxyurea, the actuarial risk was 19% at the 10th year. In the patients treated exclusively by non radio-mimetic agents (hydroxyurea or pipobroman) a risk of 10% at the 10th year was observed. The risk of carcinoma (excluding skin cancers) was about 15% at the 10th year in the 32P-treated cases, a value similar to that generally reported by the French statistics. There was no prevalence of digestive carcinomas. In contrast, the patients receiving 32P and hydroxyurea as maintenance had an excess risk: 29% at the 10th year. In the relatively young cases treated by non radio-mimetic agents, the risk was similar in both arms: 9% at the 10th year, similar to the expected incidence at this age. The risk of myelofibrosis with myeloid metaplasia was still relatively low at the 10th year, about 15% in all arms, but increased towards a value higher than 30% in the patients surviving at the 20th year. At the present time, but in only a few cases with long-term following, no myelo-fibrosis with splenic metaplasia has been observed in the pipobroman-treated cases. The present results, which need to be confirmed (the present analysis has been done in spring 95) suggest that:-the use of non radio-mimetic agents does not protect against leukemic transformation, which may be a consequence of the disease; rather than of the treatment,-maintenance therapy after initial use of 32P increases the risk of both leukemia and carcinoma,-and hydroxyurea does not delay the risk of developing myelo-fibrosis, in comparison with 32P alone.

Actuarial Analysis↗
PubMed1994

[Modifications of hemorheologic parameters in the course of hemodialysis in chronic renal insufficiency].

The influence of haemodialysis (HD) was assessed in 72 patients, undergoing a thrice weekly routine HD for chronic renal failure (CRF). Some of them received human recombinant erythropoietin (Eprex). Measurements were performed before and after the HD session: the erythrocyte aggregation (EA) was carried out by a laser backscattering technique with determination of the aggregation time (AT) and of the dissociation thresholds. Plasma viscosity (PV) was evaluated in an automatic capillary viscometer. Fibrinogen (Fg) levels, haematological features (blood cell count), serum proteins, creatinine, and some other biochemical parameters, were also determined. Anaemia was a common feature. Our results compared to those of a control group, confirmed the erythrocyte hyperaggregation before HD which increased during HD. PV also elevated before HD, further increased after HD; the same finding was observed for Fg. Some of these results might be related to the haemoconcentration. Significant correlations were noted between AT and PV, AT and Fg with closer correlations after HD, suggesting a strong cohesion of RBC aggregates, which enhanced during HD. Correlations were highly significant between relative variations of AT and relative variations of PV, Fg, proteins and body weight, before and after HD. Special attention was given to the group of patients under long term treatment with Eprex compared to non-treated dialysed patients: no significant difference was found between both groups. Our results are in agreement with a blood and plasma viscosity syndrome due to increased EA and with a tendency, to thrombosis reported in those patients.

Adult↗
PubMed1990

Real-time quality control: the French Minitel system.

A prototype system designed to provide real-time response to inter-laboratory proficiency testing results has been developed using the French Minitel telecommunication system. This nationwide computer networking system allows for instantaneous reporting and evaluation of results obtained on external quality assessment (EQA) samples. If a certain test is in error and presumably out of control the problem can be remedied immediately with obvious advantages to patient care.

Clinical Laboratory Techniques↗
PubMed1990

The French national system for external quality assessment.

Building upon the experience of professional organizations, which began in the 1970s, the French National Health Laboratory organized a national interlaboratory programme 10 years ago. Four thousand eight hundred laboratories are enrolled in this external quality control programme, which is compulsory for all clinical laboratories and is financed by a fee covering all expenses. Results are strictly anonymous and the programme is basically informative and educational. More than 20 surveys are conducted each year with four in haematology. During the last 10 years, the national programme has documented improved laboratory performances. The evaluations have had an impact on the instrument and reagents marketplace. Finally, it has helped the Ministry of Health to more efficiently manage the problems of laboratory medicine in France.

Blood Cell Count↗