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M Masse

Publications and source records attributed to M Masse.

10 recordsLinked to original sources
PubMed1991

[Multicenter study on the efficacy of leukocyte depletion by filtration of red cells. The Labile Blood Products Group].

To determine the actual efficacy of red cells filtration technique, the "Labile Blood Component Production" french study group, including 21 blood centers, realized a large study on more than 1,400 filtrations and 3,000 controls. 745 units of red cell concentrates (RCC) and 690 units of buffy-coat poor red blood cells (BC PRBC) were filtered through 6 commercialized leukocytes depleting filters: not less than 170 experiments per filter, tested by 3 different blood centers. Pre-filtration controls prove that buffy-coat removal, done manually or with automated equipment, involves a first leukocytes depletion about 63% and an hemoglobin loss equal to 4 g (7%). After filtration, residual leukocytes counts were performed manually in a Nageotte counting chamber. In this study, we evaluated the reliability of this simple method which accurately measures very low leukocytes counts. The variation coefficient was 25% for 2.5 leukocytes/microliter concentration (O.6 x 10(6) per filtered unit). The results, obtained from 1200 evaluated filtrations, confirm that buffy-coat removal obviously improves the filtration performances (residual leukocytes level is lower than 1 x 10(6) per unit for 78% filtered BC PRBC versus 43% filtered RCC). Furthermore, 90% of overall filtered units are containing less than 5 x 10(6) leukocytes.

Cell Separation↗
PubMed1978

Application of cell electrophoretic methods (preparative and analytical) in demonstrating the surface heterogeneity of T-lymphocytes in man.

The preparative electrophoretic method allows separation of several cell populations, which can be characterized by the usual membrane markers. This qualitative study shows a heterogeneous distribution of the T-lymphocytes from the most rapid to the slowest migration zones. The electrophoretic mobility (E.M.) of each fraction has been studied by analytical electrophoresis, which confirms the heterogeneity of T-cells. The experiments used total blood lymphocytes and rosette-forming cells with sheep red blood cells. The results obtained with the two methods were well correlated. The average migration speed of the separated populations showed a regular variation from one extreme fraction to the other. The E.M. speeds that characterize the main populations are--0.90 micrometer.sec.--1v.--1cm for the B-lymphocytes; for the T-lymphocytes,--1.10 (previously identified as the "low affinity" E-rosette FC),--1.20 and a small population centered around--1.35 (corresponding to active E rosette FC). In the T-lymphocytes separated after E-rosetting, the progresssive variation in the mean E.M. of each fraction is confirmed, as well as the existence of the previous 3 T-cell populations. Further studies have to be done, to show that each separated population does correspond with a functional differentiation.

Cell Membrane↗
PubMed1975

[Application of free flow preparative methods for the separation of blood cells].

Human blood cells can be separated using an apparatus described by Hanning and co-workers (Model FF4 Desaga Heidelberg). The method of free flow preparative electrophoresis uses a specific property of blood cells when subjected to an electric field: their electrophoretic mobility. Three regions of migration can be defined: --a high mobility region (HMR); --a low mobility region (LMR) and --an intermediate mobility region (IMR). After the electrophoretic migration, the various cell fractions are identified. If human leucocytes are subjected to an electric field (40 volts/cm) it is possible to isolate several populations which differ by their membranes electric charge. The repartition of the neutrophiles granulocytes is twofold: --one fraction of high mobility (HMR) and --one fraction of low mobility (LMR). The meaning of these two populations is being discussed. Between these teo fractions is located the lymphocyte fraction which is represented by a single peak of intermediate mobility (IMR). Eosinophiles and monocytes are concentrated in low mobility fraction (LMR). With appropriate migration parameters (80 volts/cm, various component buffers) it is possible to obtain from lymphocytes, purified by density gradient, an electrophoretic separation of T and B lymphocytes population. Histograms obtained from quantitative measures (on collected cell fractions) show an unimodal distribution. When separated cells are characterized by three membranes markers (E. Rosettes, EAC Rosettes and surface immunoglobulins) the electrophoretic heterogeneity of B and T cells is then demonstrated. With E Rosettes (T cells) the majority of T lymphocytes is distributed in HMR and IMR. With EAC Rosettes and membrane immunofluorescence (B cells markers) the majority of B lymphocytes is found in the LMR. Thus an important enrichment of T and B sub-population is obtained, but contamination from one another still remains too important. More selective methods should lead to an improvement of this cell separation.

B-Lymphocytes↗
PubMedDate not supplied

A multicenter study on the efficiency of white cell reduction by filtration of red cells.

To evaluate accurately the current performance of filtration, the French Produits Sanguins Labiles study group, composed of 21 transfusion teams, conducted a large-scale 6-month study involving over 1400 filtrations and 3000 controls. Some 745 standard red cell concentrates (RBC concentrates) and 690 concentrates previously white cell (WBC)-reduced by removal of buffy coat (BC-poor RBC concentrates) were filtered using six commercially available filters: at least 170 results were collected per filter, spread among a minimum of three teams. Prefiltration controls show that the removal (manual and automated) of the buffy coat results in an initial WBC reduction of approximately 63 percent, along with a hemoglobin loss of 4 g (7%). After filtration, residual WBCs were counted in the Nageotte manual counting chamber. The reliability of this counting method, which is simple and adapted to low WBC concentrations, was characterized in this study by a 25-percent coefficient of variation (CV) for a concentration of 2.5 WBCs per microL (i.e, 0.6 x 10(6) WBCs/filtered unit). The analysis of the results shows that, for five of six filters (1 filter was excluded), the postfiltration median value of residual WBCs was 1.1 x 10(6) in filtered RBC concentrates (n = 590), whereas it was 0.34 x 10(6) in filtered BC-poor RBC concentrates (n = 581). The difference is significant (p less than 10(-8), Wilcoxon test). Hemoglobin loss due to filtration varies according to the filter, from 5.7 +/- 2.2 to 17.3 +/- 2.5 g.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Component Removal↗
PubMedDate not supplied

Validation of a simple method to count very low white cell concentrations in filtered red cells or platelets.

The increased performance of white cell (WBC) filters makes it difficult to count precisely the number of residual WBCs. Concentrations as low as 0.01 WBC per microL cannot be determined with electronic cell counters, conventional hemocytometers, or the flow cytometric techniques currently being used. This article describes a simple, manual method using a Nageotte hemocytometer with a large-volume chamber (50 microL) to count the number of WBCs contained in red cell (RBC) suspensions (preparations A, B, and C) and in platelet suspensions (preparation D) diluted 1 in 10 pure, or concentrated two fold. To validate the method, several reference ranges, prepared by successively adding mononuclear cells to a suspension of pure RBCs or platelets, were used. Among the different series, validation ranges varied from 0.2 to 12 to 0.01 to 0.5 WBCs per microL and correlation coefficients ranged from 0.929 to 0.996. To determine the limit of accurate detection, accuracy tests (n = 160) were carried out by two experienced operators on samples with WBC concentrations of about 5, 10, and 120 times the concentration at the theoretical limit of detection (1 WBC/chamber). No significant difference was observed in the various types of preparations (A, B, C, D) in the tests performed by the two operators. However, intra-assay coefficients of variation were 18, 9.5, and 2.2 percent, respectively, at WBC concentrations of 5, 10, and 120 times that at the theoretical limit of detection. These observations show that a limit of accurate detection (10%) seems to be reached when 10 cells are observed in a Nageotte hemocytometer.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Platelets↗
PubMedDate not supplied

[Treatment of immediate post-operative agitation (author's transl)].

Though organic causes and operative factors can produce post-operative agitation, a background of anxiety, alcoholism, or neurosis plays a major role in its development. Excellent results were obtained with tiapride in 58 patients with post-operative agitated states. Local and general tolerance were both excellent. Furthermore, an association of tiapride-corticoids was effective in treating post-anaesthetic spasm of the glottis.

Adolescent↗