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Biomedical subjects

F Beaujean

Publications and source records attributed to F Beaujean.

87 records · Page 5Linked to original sources
PubMed1982

[Red cell preservation by freezing at -25 degrees C].

A method of red cell preservation by freezing at -25 degrees C is described. Glycerol is added to the red blood cells in the primary polyvinyl chloride plastic collection bag to achieve a concentration of 28 pr cent (W/V). The blood cells are concentrated by centrifugation and the supernatant glycerol is discarded. Glycerolized red cells are frozen and stored at -25 degrees C for 1 to 6 months. After thawing, Sodium chloride solutions are used to wash the red cells in the IBM Blood Processor 2991. The following parameters have been investigated before freezing, after thawing and washing and after storage of red blood cells at 4 degrees C for 24 hours: --Hemoglobin level --leukocytes and platelets --amount of 2-3 DPG and ATP. Preliminary data show that the in vitro quality of erythrocytes stored at -25 degrees C is well preserved for 4 months and that this simple method can be applied to blood preservation in any Blood Center.

Adenosine Triphosphate↗
PubMed1976

[Ventrale derotations-spondylodesis (author's transl)].

Results about 26 cases operated with the new developed "Ventrale Derotations-Spondylodesis". The first results with this new method are better than the results of the Harrington and the Dwyer method as it allows the operative derotation and lordosation. The risk of the operation put in relation to the distraction method by Harrington seems less. The importance of the operation one can't put into relation to the rather simple postoperative treatment. The results of the first 19 cases give the impression that the advantages of the Ventral Derotations-Spondylodesis make this method prefer to other instruments in the operative treatment of scoliosis.

Bone Plates↗
PubMed1976

[Value of using cell concentrates, preserved by freezing, during extracorporeal circulation].

The effectiveness of transfusions of frozen red cells has presently been clearly demonstrated. The authors present their technique of preparation of these cells and their experience of this material in 51 cases of ECC. The results observed plead in favour of the notion that frozen-defrosted blood, combines the advantages of washed blood, freed from all plasma and cellular contaminants of fresh blood with preservation of the oxyphoric power. Going beyond the realm of ECC, the authors think that cryopreservation of blood should be applied to the majority of indications for transfusions.

Blood Preservation↗
PubMed1975

[Post-hepatitic aplasia treated by grafts of allogenic bone marrow. Remission for more than 2 years. Persistance of a total hematopoietic chimera. Graft versus host reaction].

A successfull bone marrow transplant was achieved in a case of post hepatitic aplastic anemia after cyclophosphamide immunosuppression. Caryotype analysis, erythrocytic phenotype and IgG Gm allotype demonstrated evidence of complete chimerism. Anti-thymocyte serum undoubtly was able to suppress a life threatening episode of graft versus host reaction. Severe long lasting skin lesions are now persisting 2 years after the graft.

Adolescent↗
PubMed1975

[Preservation of erythrocytes by freezing in liquid nitrogen. Use of an I.B.M. blood regenerator].

The freezing of blood permits preservation of red cells over long periods of time, several months or years. Leucocyte and platelet contamination of red cell concentrates to be frozen is negligible. The amount of the various red cell metabolites (2.3 D.P.G., A.T.P., etc.) is maintained. Washing of thawed red cells removes the remaining plasma proteins and cell residues. The freezing method employed is that of Row et al. The protector used is 28% glycerol added in equal amounts to red cell concentrate to be frozen. The blood bag is kept in liquid nitrogen at -- 196 degrees C. Thawing takes place in a water bath at 45 degrees C. Wash solution is the IBM Blood regenerator. The solution used for removing glycerol is hypertonic natrium chloride. The following parameters have been investigated: --hemoglobin level; --osmotic fragility; --the amount of 2.3 D.P.G.; --residual glycerol after thawing; and clearance of leucocytes and platelets following each step of the protocol. Preliminary data regarding these features and therapeutic efficiency of processed blood are satisfactory.

Blood Preservation↗
PubMedDate not supplied

Separation of large quantities of mononuclear cells from human blood using a blood processor.

A blood processor (IBM 2991) was used to separate lymphocytes from large volumes of blood. The procedure included the centrifugation of 200 ml whole blood on a density gradient. The results of this procedure were compared with those obtained with a manual procedure. Mononuclear cell (MNC) viability was preserved well in the two methods. But with the processor, recovery of MNC was better (63.5 +/- 2.5%) than with manual separation (26.5 +/- 4.1%). Monoclonal antibodies were used to identify the various cell subsets in the MNC fractions. No particular cell selection was observed when MNC fractions were obtained by the separator. In conclusion, the use of a cell separator provided an efficient technique for rapid isolation of large quantities of lymphocytes.

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

Peripheral blood stem cell collection with a blood cell separator.

Forty-three patients with malignant nonmyeloid diseases underwent peripheral blood stem cell collections on an apheresis system (Spectra, COBE BCT, Lakewood, CO). Collections took place during the white cell (WBC) recovery phase following conditioning chemotherapy. One hundred two procedures were done after chemotherapy alone, and 72 procedures after chemotherapy plus granulocyte-colony-stimulating factor (G-CSF). Four centrifugal separation factors were tested. One and one-half patient blood volumes were processed in each procedure. The mean volume of the collected component was 158 +/- 16 mL. After chemotherapy alone, the procedures provided a mean of 0.8 x 10(8) WBCs per kg and 2.3 x 10(4) colony-forming units-granulocyte macrophage (CFU-GM) per kg of recipient body weight. The mononuclear cell percentage in the components increased with the centrifugal separation factor from 85 to 96 percent. In parallel, platelet contamination increased from 2.1 to 3.8 x 10(11). The collect hematocrit ranged from 1.0 to 2.5 percent (0.01-0.025). The collection efficiency for mononuclear cells and CFU-GM also increased with the centrifugal separation factors from 52 to 70 percent for mononuclear cells and from 55 to 68 percent for CFU-GM. Collections performed after G-CSF-stimulated mobilization were characterized by a higher neutrophil contamination independent of centrifugal separation factor, which gave a mean mononuclear cell percentage of 64 percent in the collected component. The average yield for these procedures was 2 x 10(8) WBCs per kg and 28 x 10(4) CFU-GM per kg.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Positive selection of autologous peripheral blood stem cells.

The development of monoclonal antibodies against differentiation antigens on human haematopoietic cells has led to a new concept in stem cell purification: the positive selection. In terms of autologous PBSC transplantation, the immature stem cells are identified by their expression of a specific antigen, the CD34. The CD34 antigen is expressed on early lymphohaematopoietic stem cells and progenitor cells, but not on mature blood cells or on tumour cells of several diseases. CD34+ cells are found in low numbers in bone marrow (<2%) and in even lower numbers in steady state blood (<0.01%) but may increase from 1 to 5% after mobilization using chemotherapy and/or growth factors. Several techniques have been set up to enrich PBSC grafts in CD34+ stem cells. The quality of each system is here analysed in terms of CD34 purity of the selected cell fraction, the CD34 cell recovery, the tumour cell depletion efficiency and the functional capacity ex vivo and in vivo of the selected cells. The final CD34+ cell purity of the selected fractions is correlated to the concentration of CD34+ cells before selection. The optimal recoveries and the highest purities were generally obtained when the initial CD34 content was roughly over 1%. Below this figure, the final purity seems to be less predictable. Besides the better tolerance resulting from the reduction in the number of autologous cells, and consequently the total volume of DMSO reinfused to the patient, the selective enrichment of the CD34 cell population offers a new approach to tumour purging. The procedure by itself results in elimination of about 99% in the total number of initial cells, thus allowing reduction of the overall tumour cell number in the final autograft. However, its major interest is that, in diseases where tumour cells do not express the CD34 antigen, it is theoretically able to completely eliminate the tumour contamination of the graft. Based on previous data showing that lymphoma, myeloma, neuroblastoma and breast cancer cells are not CD34+, pilot clinical trials for the separation and transplantation of CD34+ cells selected from PBSC of patients with these diseases have recently been conducted. The efficacy of CD34 selection in reducing the tumour load of the PBSC of patients with these diseases has been reported. However, the efficacy of purging may greatly differ between individual patients, and complete eradication of contaminating cells from PBSC grafts was not always reached. There is now evidence that purified CD34+ cells are capable of supporting haematopoietic reconstitution in autologous transplantation. However, until now no study has demonstrated clear evidence that the reduction of tumour cells from PBSC of patients by CD34+ cell selection resulted in a lower relapse rate post-transplant, as compared to unselected PBSC infusion.

Antigens, CD34↗