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At least 181 records · Page 10Linked to original sources
PubMed2003

Comparison of CD34+ cell collection on the CS-3000+ and Amicus blood cell separators.

BACKGROUND: Mobilized PBPCs, detectable on the basis of CD34 expression, can be collected on various cell separators. The CD34+ cell collection efficiencies of two cell separators (CS-3000+ and Amicus, Baxter) were tested on two comparable groups of oncology patients. STUDY DESIGN AND METHODS: Leukapheresis assisted by the standard manufacturer's software and variables settings was performed in 37 (CS-3000+) and 34 (Amicus) patients (total of 83 and 67 collections, respectively) after chemotherapy plus G-CSF treatment. RESULTS: The total CD34+ cell count per leukapheresis components as well as per kg of patient's body weight were twofold higher by using the Amicus than the CS-3000+ device. Platelet contamination in Amicus components was twice as low compared to the CS3000+. Mean Amicus CD34+ collection efficiency (CD34+eff) (54.9 +/- 27.2%) was significantly higher (p < 0.015) than the CS-3000+ (46.4 +/- 16.7%) one. However, Amicus CD34+eff decreased progressively as the peripheral blood CD34+ concentrations increases over 200 CD34+ cells per microL. A parallel increase in the WBC counts in these cases seems to be the principal cause of decrease in CD34+eff (evident for WBCs >40 x 10(3)/microL and most pronounced for WBCs >60 x 10(3)/microL). CONCLUSIONS: Mean CD34+eff and CD34+ cell yields were better on Amicus than on CS-3000+. CD34+eff of Amicus, however, seems to be related to the initial WBC counts, decreasing progressively when WBC increased over 4 x 10(3) per microL that coincided with the increase in CD34+ cell concentrations. For these cases, the volume and duration of cycles should be adapted to optimize CD34+ collections by using Amicus separators.

Adult↗
PubMedDate not supplied

Drug sensitivity tests after cell separation on density gradients.

Cells from two leukaemic cell lines (K562 and L1210) were separated on a discontinuous Percoll gradient with densities from 1040 to 1090 by centrifugation. The cells recovered from gradient interfaces were checked for their DNA content and subjected to two different drug sensitivity tests using three cytostatic drugs. The purpose of the study was to compare the sensitivity of a sample of the whole population with that of the fractions thus obtained. Depending on the test used and the line tested, there was a 5.5 to 55.5% discordance between the results for the fractions and the non-separated cells.

Animals↗
PubMed1997

[Technical aspects of extraction of platelet concentrates from dogs with an automated cell separator].

The results of this work point out that the cell separator AS 104 (Fresenius AG, Bad Homburg), which is developed to obtain platelet concentrates from human beings, can be used for dogs. The base adjustment of the cell separator for human beings (adjustment I) is useful, because of the high yield [platelet count (median): 1.75 x 10(11)] and quality [low leucocyte- (40/microliter) and erythro count (10 x 10(3)/microliter)]. In addition, there was no clear difference between the base adjustment (adjustment I) and an empirical modification (adjustment II). The platelet count of the donor dog decreased during the separation by approximately 140,000/microliter and reached the initial value after four days. Supplementary, the time course of the haematocrit and the concentrations of albumin, total protein and total calcium of the donor dog were measured. It should be mentioned that the concentrations of ionized calcium distinctly decreased during the separation. Synchronously, the concentrations of ionized calcium and of citrat reached the starting-counts 3-4 hours after the ending of the separation.

Animals↗
PubMed1997

Leukocyte filtration of single-donor platelet units through an integrated filter system for the Fresenius AS 104 blood cell separator.

BACKGROUND AND OBJECTIVES: White cell depletion of platelet concentrates is widely applied to reduce the incidence of transfusion complications. We investigated a new plateletpheresis kit with an integrated filter for leukocyte depletion of platelets. MATERIALS AND METHODS: Parameters of product quality were investigated before and after in-line filtration of 70 single-donor platelet (SDP) units obtained by apheresis. We studied three different filter batches manufactured for the Fresenius AS 104 blood cell separator, and evaluated different softwares and interface positions with respect to platelet (PLT) yield and white blood cell (WBC) contamination. RESULTS: PLT yields before and after filtration was not statistically different in the protocols studied. WBC contamination after WBC depletion was in the range of 10(4)/SDP unit. Glucose, lactate dehydrogenase, and the morphology score were not statistically different before and after filtration. CONCLUSIONS: In-line WBC filtration of SDP units sufficiently reduced WBC below 5 x 10(6)/unit. The study allowed definition of the filter composition and apheresis parameters to optimize PLT yield and minimize WBC contamination.

Filtration↗
PubMed2000

Cell separation by dielectrophoretic field-flow-fractionation.

Dielectrophoretic field-flow-fractionation (DEP-FFF) was applied to several clinically relevant cell separation problems, including the purging of human breast cancer cells from normal T-lymphocytes and from CD34+ hematopoietic stem cells, the separation of the major leukocyte subpopulations, and the enrichment of leukocytes from blood. Cell separations were achieved in a thin chamber equipped with a microfabricated, interdigitated electrode array on its bottom wall that was energized with AC electric signals. Cells were levitated by the balance between DEP and sedimentation forces to different equilibrium heights and were transported at differing velocities and thereby separated when a velocity profile was established in the chamber. This bulk-separation technique adds cell intrinsic dielectric properties to the catalog of physical characteristics that can be applied to cell discrimination. The separation process and performance can be controlled through electronic means. Cell labeling is unnecessary, and separated cells may be cultured and further analyzed. It can be scaled up for routine laboratory cell separation or implemented on a miniaturized scale.

Animals↗
PubMed1989

Relation between cell cycle stage and the activity of DNA-synthesizing enzymes in cultured human lymphoblasts: investigations on cells separated according to DNA content by way of a cell sorter.

Exponentially growing human lymphoblasts (culture LS-2) were separated by cell sorting (FACS II, Becton Dickinson) according to their deoxyribonucleic acid (DNA) content, designating them at particular phases of the cell cycle. Prior to cell sorting the DNA has been fluorochrome-labeled with the Hoechst stain H 33342. Maximum cell enrichments of 94% for G0 + G1 cells, 96% for S cells and 74% for G2 + M cells could be achieved. The enzyme activities of thymidine kinase (TK), thymidylate synthase (TS), DNA polymerase (DNA-P), dihydrofolate reductase (FH2-R), methionine synthase (MS), and hexokinase (HK) were determined in the obtained cell fractions. Although incorporation of 3H-thymidine (3H-dTR) and the 3H-dTR labeling index were significantly inhibited by the dye, no evidence of cell staining's having a significant effect on the enzyme activities was found. The enzyme activities for approximately 100% pure G0 + G1, S, and G2 + M cells were computed. With exception of TK, all the enzymes under study were shown to exhibit activities--although of differing degree--in the G0 + G1, S, and G2 + M cells. No TK activity was shown in G0 and G1 cells; its activity, however, was approximately the same in S and G2 + M cells. This applies likewise for TS which, in contrast to TK, exhibits minor activity in G0 + G1 cells. DNA-P was highly active in G0 + G1 cells, but maximum activity was in S cells. FH2-R exhibited maximum activity in S cells, although the difference in activity between S and G2 + M cells was not significant. None of the observed differences in MS activity was significant, indicating equally high activity in cells of all cell cycle phases. HK activity is approximately twice as high in G2 + M cells as in G0 + G1 cells.

Benzimidazoles↗
PubMed1982

Donor symptomatology and safety in blood cell separation procedures.

Increasing demands for platelet and granulocyte concentrates collected by cell separation technology for replacement strategies requires expanding available donor pools, related or unrelated by recruiting additional donors or increasing the frequency with which a donor is processed. The expanding application of cell separation devices for plasma or red cell exchange as a therapeutic modality for many medical diagnoses now exposes patients with altered physiology to technology and procedures originally designed for healthy blood component donors. Some possible risks from the technology and/or procedure are discussed. Donor symptomatology from the chemical agents used in blood processing and a relationship to scheduling frequency are introduced.

Adult↗
PubMed1987

The use of fluorescence quenching in flow cytofluorometry to measure the attachment and ingestion phases in phagocytosis in peripheral blood without prior cell separation.

Flow cytofluorimetry identifies and quantifies cell markers of different leukocyte subpopulations by combining cytofluorimetry with the differences in the light scattering properties of the leukocytes in mixed populations. In the phagocytic assay, reported in this paper, the experimental conditions were selected in such a way that it was possible to analyse the phagocytic function of granulocytes in peripheral blood without time-consuming cell separation. The percentage of phagocytosing granulocytes was not dependent on the concentration of granulocytes at the selected incubation time and particle (yeast-C3b) concentration. Furthermore, it was possible to adapt a previously described fluorescence quenching technique (FQ method) to differentiate between attachment and ingestion. Crystal violet, originally used in the FQ method, could not be used in this assay due to its lysomotropic effect. Trypan blue at a concentration of 0.25 mg/ml or higher at pH 4.5 showed a plateau effect in fluorescence quenching indicating an effect on attached but not ingested particles. This assay offers a simple technique to screen the functional properties of phagocytic cells in peripheral blood.

Cell Membrane↗
PubMed1975

[The use of the cell separator in the treatment of leukemia].

In order to provide leukemic patients during the critical granulocytopenic stage with a sufficient amount of granulocytes a blood cell separator with a continuous extracorporeal circulation was developed. This permits to obtain up to 3.0-10(10) leukocytes during a 4---5 hours period from a single donor. According to our own experiences with 20 leukophereses performed in 13 healthy donors by the use of the AMINCO cell separator an average of 1.17-10(10) leukocytes with a granulocytic portion of 61% was collected per run. In two cases of agranulocytosis and septic fever (one case of pseudomonas septicaemia) the repeated administration of leukocyte concentrates, while specific antibiotic therapy was continued, led to a marked improvement over a longer period of time. Furthermore thrombocyte concentrates up to 7.0-10(10) platelets can be obtained by the cell separator. Applied as depletory method in the treatment of CML and CLL leukopheresis may rapidly diminish the peripheral leucocyte count while spleen and lymphomas decrease in size at the same time. A 20% reduction in cell count may be achieved by a serie of 3---4 leukophereses. Also the use of the cell separator in the treatment of makroglobulinemia by plasmapheresis is discussed.

Adolescent↗
PubMed1991

Cell separation system studied by mixed culture of single wild strain with tetrads-forming mutant strain of Micrococcus luteus.

Mixed culture study of singly occurring wild strain IFO 3333 of Micrococcus luteus and a tetrads-forming mutant strain MT, in the absence or presence of trypsin, supported our previous assumption that at least two kinds of separation systems were involved in cell separation of M. luteus, the one having a physiological role in cutting off the outermost layer of the cell wall (separation system-Om) and the other in cutting off the inner layer of the "proper" cell wall or the septum (separation system-In). The separation system-Om of IFO 3333 insensitive to trypsin substituted, freely from the cells, for that of MT sensitive to trypsin.

Micrococcus luteus↗
PubMed1979

Mode of cell separation and arrangement of Staphylococcus.

The process of cell separation and arrangement of Staphylococcus was investigated using a scanning electron microscope. After two cycles of cell division, the Staphylococcal cells cultured on an agar medium were generally observed to be arranged in three morphological types: linear, square, and crooked arrangements. Results of the examination of cell surface structure revealed that separations had occurred in these clustered cells following two patterns. One type of second separation occurred parallel to the transversal axis of the preceding pair of the parental cells (X-type) and the other occurred tangential to it (Y-type). In the former type, the four daughter cells were usually arranged tetragonally after the separations, and in the latter type they were arranged either linearly or crookedly depending on the direction of the second separation. The final pattern of the cell arrangement was thus determined by the type of septal wall formation and the direction of cell separation. After several cycles of cell divisions, the cells were finally arranged in an irregular grape-like cluster, even though the cross walls were formed regularly at the rectangular face of the preceding cross walls.

Cell Division↗
PubMed1981

[Discontinuous cell separation as depletion therapy in chronic leukemias].

Blood cell separators have been successfully used in the treatment of chronic leukaemias. With the intermittent flow system Haemonetics model 30, we found it important to collect 150-300 ml buffy coat/cycle in order to obtain a substantial depletory effect. In 2 patients with chronic myeloid leukaemia on short-term leukapheresis and in 1 patient with prolymphocytic leukaemia on long-term leukapheresis we found a definite decrease in the WBC count. 2 of them experienced a transitory improvement of their disease. Only minor side-effects occurred. However, the loss of erythrocytes and plasma albumin necessitated replacement therapy. From our experience the intermittent flow blood cell separator can be successfully used in the treatment of well-defined forms of chronic leukaemia.

Humans↗
PubMedDate not supplied

Exchange transfusion in sickle cell disease using a continuous-flow blood cell separator.

An exchange transfusion was performed preoperatively on a patient with sickle cell disease using a continuous-flow blood cell separator. An exchange of 2,825 ml red blood cells achieved a hemoglobin A level of 90.8 per cent. The continuous-flow blood cell separator appears to offer a safe and effective method of exchange transfusion in sickling disorders.

Adult↗
PubMed1978

Transfer of mouse IgG2 production by IgM-bearing spleen cells separated by a fluorescence-activated cell sorter.

The purpose of the present study was to determine whether at least some splenic B lymphocytes can switch from the synthesis of one isotype of immunoglobulin to another during B cell differentiation. The experimental system invovled the transfer of characterized cell suspensions between allotype congenic strains of mice followed by analysis in the recipient for donor type immunoglobulin production. Donor splenic lymphocytes were incubated with specific fluorescent labelled anti-mu antiserum and passed through the Los Alamos fluorescence-activated cell sorter; mu-depleted cell suspensions were transferred into sublethally irradiated congenic recipients and the amount of donor type immunoglobulin of IgG2 type was measured at weekly intervals. The results demonstrated taht at least some cell bearing membrane bound IgM can differentiate in vivo into IgG2-secreting cells, although not all IgG2-secreting cells have been recently derived from IgM positive precursors.

Animals↗
PubMedDate not supplied

Flow through, immunomagnetic cell separation.

A brief, process-oriented overview of immunologically based cell separation technology is presented. In addition, the design and preliminary experimental data of two unique flow-through immunomagnetic cell separation devices are presented. The first design is based on a dipole magnetic field, while the second design is basis on a quadrupole magnetic field. The dipole design can "fractionate" an inlet, magnetically labeled, cell stream into different outlet streams on the basis of the degree to which the cell is immunomagnetically labeled. The quadrupole separator splits an inlet, immunomagnetically labeled, cell stream into two outlet streams in which the purity, recovery, and potentially the degree to which the cells are immunomagnetically labeled is controlled by the flow rates in the inlet and outlet flows. A 99% purity and 86% recovery have been achieved with this system. Some distinct advantages of these two systems are the potential of high purity, recovery, and throughput at a cost which is potentially significantly lower than current, comparable technologies.

Electrochemistry↗
PubMed2000

Cell separation improves the sensitivity of detecting rare human normal and leukemic hematopoietic cells in vivo in NOD/SCID mice.

BACKGROUND: This report describes a novel cell-separation procedure developed to improve detection and analysis of rare human hematopoietic populations, obtained from NOD/SCID mice engrafted with normal and/or leukemic stem cells. METHODS: In preliminary experiments, artificial mixtures of murine and human BM cells were labeled with a combination of Abs specific for murine hematopoietic cells, prior to immunomagnetic negative selection using StemSep. In subsequent experiments, BM was harvested from individual NOD/SCID mice transplanted 6-12 weeks earlier with either human cord blood or primary CML cells and a similar immunomagnetic selection procedure was applied to enrich human cells present. RESULTS: Application of this selection procedure to mixtures of murine and human hematopoietic cells using anti-mouse CD45 and Ter-119 allowed a > 1000-fold depletion of murine cells with > 50% recovery of human cells, including progenitors. This level of depletion and recovery were found to be reproducible for NOD/SCID mice transplanted and engrafted with human cord blood stem cells, thus facilitating detection of human progenitors, including colony-forming cells (CFC) and LTCIC. For NOD/SCID mice previously transplanted with CML cells, this procedure increased the sensitivity of detecting rare human cell subsets by up to > 100-fold. This, in turn, improved the sensitivity of RT-PCR for BCR-ABL and made possible the identification by FACS of various minor subsets of human cells, including CD34(-)CD19/20(+) B-lineage cells, CD34(+) progenitors, mature CD15(+) myeloid cells and CD3(+) T cells present in the mice. DISCUSSION: This simple cell-depletion procedure should facilitate future investigations of normal and CML stem cell populations in vitro and in NOD/SCID mice.

Animals↗
PubMed1995

[Comparison of platelet and leukocyte content in platelet concentrates obtained from CS-3000 and third generation (CS-3000 plus and Cobe-Spectra) cell separators].

Platelet concentrates (PCs) obtained using old generation of cell separators contain high number of leukocytes. White cell (WBC) contamination and platelet (Plts) number in PCs obtained from separator II-nd generation CS-3000 and separators III-rd generations CS-3000 plus and Cobe-Spectra have been determined. PCs from new separators contain the same Plts number as PCs from CS-3000. The average leukocyte count in PCs obtained from CS-3000 was 171.26 x 10(6), whereas WBC number in PCs from CS-3000 plus and Cobe-Spectra were 2.87 and 2.54 x 10(6) respectively. In about 85% of PCs obtained from III-rd generation cell separators the leukocyte count did not exceed 5 x 10(6). This count is considered sufficient to prevent alloimmunization of HLA antigens. The determination of WBC count in every PCs allows to select PCs with fewer than 5 x 10(6) leukocytes and to transfuse them without the necessity of using expensive filters for leukocyte removing.

Blood Platelets↗