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At least 307 records · Page 17Linked to original sources

PubMed2005

Factors influencing yield of plateletpheresis using intermittent flow cell separator.

Platelet recovery in the recipient is influenced by the transfused dose of platelets, which in turn is dependent on the quality of single donor platelets (SDPs) in terms of platelet yield. Various donor factors such as predonation platelet count and Hemoglobin (Hb) concentration affect the platelet yield. A total of 61 plateletpheresis procedures performed on intermittent flow cell separator (MCS3p, Hemonetics) were evaluated for platelet yield. A relationship between predonation platelet count and Hb concentration with yield of platelets was studied using Pearson Correlation. The mean platelet yield was 2.9 +/- 0.64 x 10(11). While a direct relationship was observed between predonation platelet count and yield (r = 0.51, P < 0.001), no such correlation was noticed with donor Hb concentration (r = -0.05, P > 0.005). The yield was > or =3 x 10(11) in >80% of procedures when the predonation platelet count was > or =250 x 10(3)/mm. Optimization of platelet yield, which is influenced by predonation platelet count, is an emerging issue in blood transfusion services. However, further studies in this regard are needed using more advanced cell separators.

Adolescent↗

PubMed2001

Differential response of mast cells separated from various organs and basophils of dogs to the fluoroquinolone antimicrobial levofloxacin.

Histamine releases induced by the fluoroquinolone antimicrobial levofloxacin (LVFX) were investigated using mast cells separated from various organs and peripheral basophils of dogs, being the most susceptible species to quinolone derivatives, in both in vivo and in vitro systems. An intravenous infusion of LVFX at 30 mg/kg over a 30-min period produced endogenous histamine release from 5 min, and a maximum at 30 min, in which the plasma LVFX concentration was approximately 50 microM. A close correlation (r = 0.87, n = 20) between histamine and LVFX concentrations in plasma during the infusion was observed. In the in vitro study, LVFX at 30 microM or more caused histamine release from mast cells separated from the liver and skin, but not from the gastric mucosa, lung, and peripheral basophils. More exactly, the liver mast cells were most susceptible to LVFX among the organs tested. On the other hand, compound 48/80, a prototype histamine liberator, elicited the histamine release from the liver or skin mast cells at 10 microg/ml, and the calcium ionophore A23187 at 1 microM exhibited the histamine release from the mast cells derived from all organs examined. Histochemical analysis revealed that the liver and skin mast cells had positive reaction for both alcian blue and safranin staining, but the gastric mucosa and lung mast cells were only positive for alcian blue staining, indicating that LVFX preferably activated the connective tissue-type mast cells rather than the mucosal-type mast cells. The degranulation of the liver and skin mast cells brought about by either LVFX or compound 48/80, unlike the calcium ionophore A23187, was blocked by pretreatment with pertussis toxin, suggesting the involvement of pertussis toxin-sensitive G proteins. The results obtained from the canine experiments strongly suggest that LVFX induces histamine release from the connective tissue-type mast cells distributed mainly in the liver, somewhat in the cutaneous tissue, through the activation of pertussis toxin-sensitive G proteins.

Animals↗

PubMed2003

Effect of plateletpheresis on complete blood count values using three different cell separator systems in healthy donors.

The aim of this study is to investigate changes of CBC values after plateletpheresis in healthy and volunteer donors by using three different cell separator systems. The platelets were collected from 95 donors using the COBE Spectra, from 87 donors using the Fenwal CS-3000 Plus, and from 83 donors using the Fresenius AS-204. After plateletpheresis, white blood cells (WBC), hemoglobin (HGB), hematocrit (HCT), and platelets (PLT) were decreased significantly. When we used the COBE Spectra, the drop in the values of HGB and HCT was significantly less than for the other devices. It is recommended that hematological parameters should be monitored carefully in donors who are supposed to undergo long-term regular apheresis, and to prevent the occurrence of an artificial anemia, which is likely to happen. Selection of cell separator systems should be based on this possibility.

Blood Cell Count↗

PubMed2001

An investigation into the suitability of silica beads for cell separations based on density perturbation.

This study has investigated possible alternative types of beads for fractionating cells on the basis of density perturbation. It is well known that uniform magnetic beads can be extremely important tools for separating cells by both magnetic separation techniques and density perturbation. However, because of the inherent expense associated with the use of magnetic beads, it was decided to study the possible use of inexpensive silica beads for density perturbation in terms of their attachment and modification of density of cells and to compare them with uniform Dynabeads. Silica beads were analyzed to determine their size and effect on the density of cells. Differentiated HL60 cells were used as a model system. As differentiation occurs, different levels of antigens are expressed on the cell surface and this results in different numbers of beads binding to cells. DMSO-differentiated HL60 cells were mixed with anti-CD11b-coated beads at a ratio of 20:1 (beads/cell), and gentle mixing was carried out at 20 degrees C on the end-over-end mixer. The binding of antibody-coated silica beads and Dynabeads to partially differentiated HL60 cells were compared. The conclusions reached on the basis of these experiments are that antibody-coated silica beads (Ab-coated silica) can be used as alternative beads for some cell fractionations. However, compared with Dynabeads, there are more beads that are only transiently associated with cells, possibly indicating that higher levels of detachment of beads from cells occur when silica beads are used. In addition, silica beads are usually heterogeneous in size and this would make it difficult to use these beads for the isolation of purified subpopulations of differentiated cells.

Cell Count↗

PubMed1990

Bone marrow processing on the Haemonetics V50 cell separator.

We have processed 27 bone marrow (BM) harvests using the Haemonetics V50 cell separator with a paediatric plasmapheresis set and programmed for lymphocyte collection. The mean starting volume of 843 mL was processed in 6-8 cycles to a buffy coat (BC) with a mean volume of 230 mL. The mean starting mononuclear cell (MNC) count was 1.22 x 10 8/kg recipient weight, and recovery was 92%. Clonogenic potential of the BC was assessed using CFU-GM assays and recovery was measured after cryopreservation or purging. On 4 occasions where major ABO incompatibility existed between donor and recipient, both BM and BC were consecutively diluted in compatible blood and processed twice. This achieved a calculated reduction in donor erythrocytes of 98%. The procedure was efficient and yielded a BC fraction suitable for cryopreservation and purging. Adequate stem-cells were retained as verified by CFU-GM assays and documentation of stable engraftment.

Adolescent↗

PubMed2003

Medical Devices; hematology and pathology devices; reclassification of automated blood cell separator device operating by filtration principle from class III to class II. Final rule.

The Food and Drug Administration (FDA) is reclassifying the automated blood cell separator (ABCS) device operating by filtration principle, intended for routine collection of blood and blood components, from class III to class II (special controls). The special control requirement for this device is an annual report with emphasis on adverse reactions to be filed by the manufacturer for a minimum of 3 years. The agency is taking this action in response to a petition submitted under the Federal Food, Drug, and Cosmetic Act (the act) as amended by the Medical Device Amendments of 1976 (the 1976 amendments), the Safe Medical Devices Act of 1990 (the SMDA), and the Food and Drug Administration Modernization Act of 1997 (FDAMA). The agency is reclassifying the automated blood cell separator devices operating by filtration principle into class II (special controls) because special controls, in addition to general controls, are capable of providing a reasonable assurance of safety and effectiveness of the device.

Device Approval↗

PubMed1993

[Single needle results with A-201 and AS-104 cell separators].

In plateletpheresis, new single-needle techniques have been developed for the cell separators A 201 (Baxter) and AS 104 (Fresenius). These new techniques were studied concerning donation time, ACD consumption, platelet yield, separation efficiency, erythrocyte and leukocyte contamination. The total amount of thrombocytes and the separation efficiency were significantly better with the single-needle version of the AS 104 apparatus than with the A 201 device. The contamination values were significantly lower with the AS 104 machine.

Cell Separation↗

PubMed1999

Annexin V and platelet antigen expression is not altered during storage of platelet concentrates obtained with the AMICUS cell separator.

During storage of platelet concentrate the so-called "storage lesion" occurs. During this time, platelets loose their morphological and functional capacities that are necessary for proper in vivo efficacy following transfusion. Annexin V represents a marker for apoptosis. In this study, Annexin V and additional antigens were analyzed by flow cytometry. Platelet concentrates were obtained with a new cell separator (AMICUS Separator, Fenwal). Following apheresis, platelet units were stored for an experimentally prolonged time of seven days. Daily aliquots of the platelet-rich plasma were obtained to measure Annexin V and platelet antigens CD62p, CD63, CD41a, CD42b, and the binding of fibrinogen. All analyses were performed using flow cytometry. During storage, no significant changes in mean channel fluorescence intensity (MCFI) of CD41a (P = 0.99) and CD42b (P = 0.29), percentage of CD62p+ and CD63+ platelets (P = 0.23 for CD62p; P = 0.52 for CD63), and the binding of fibrinogen to platelets occurred (P = 0.85). Also, the expression of Annexin V remained constant with no significant change (P = 0.36). This study shows that antigens of platelets, obtained with the AMICUS cell separator are well preserved during storage. Regarding Annexin V, no obvious signs of apoptosis can be detected by flow cytometry. These findings demonstrate the high degree of biocompatibility of the apheresis device and storage container.

Annexin A5↗

PubMed1999

Bone marrow processing for transplantation using the COBE spectra cell separator.

BM processing, volume reduction, and granulocyte and erythrocyte depletion are important considerations for minimizing the side effects of graft administration and bypassing ABO incompatibility in allogeneic BMT. We used the COBE Spectra cell separator for BM processing in 33 patients suffering from hematologic malignancy and solid tumor (median age 39 years). We processed 42 BM harvests with the aim of maximizing recovery of mononuclear cells (MNC). BM was collected from the posterior iliac crest under general anesthesia. The mean volume of collected BM before filtration was 1,303 ml, and the mean number of collected total nucleated cells (TNC) was 2.61 x 10(8)/kg. The BM processing resulted in a mean recovery of 35.8% (10.1%-78.3%) TNC, 22.3% (1.1%-75.7%) of granulocytes, 78.8% (34.3%-135.2%) of MNC, 77.2% (8.3%-260.0%) of CD34+ cells, and 153.3% (32.9%-464.0%) of colony-forming units (CFU-GM) in the final product. A mean of 98.2% (94.5%-99.5%) of RBC was removed, with a mean of 13.3 ml (5.1-26.2 ml) of RBC in the final product. BM processing using the COBE Spectra cell separator proved to be fast, safe, and effective. However, the reasons for the very wide range of recovery of harvested CD34+ cells and CFU-GM need to be further investigated.

Adult↗

PubMed2002

Leukocyte apheresis using a centrifugal cell separator in refractory ulcerative colitis: a multicenter open label trial.

Recently, successful results of ulcerative colitis (UC) treatments with leukocyte apheresis have been reported by several institutes. To certify the efficacy of leukocyte apheresis in refractory UC patients, a multicenter open label trial was conducted, and results were analyzed. Fifty patients diagnosed with active steroid-resistant UC were enrolled in this study from 14 medical centers. Using a centrifugal cell separator (Component Collection System, Haemonetics), leukocyte apheresis was performed once a week for 5 weeks. General conditions and abdominal symptoms were recorded daily, and laboratory tests were followed weekly. Changes of colonoscopic and histological manifestations of luminal activity through the study period were evaluated. At the end of the study period, stool frequency was decreased to less than 4 times a day in 68.4% (26 of 38) and serum C-reactive protein (CRP) concentration was normalized in 56.7% (17 of 30) of the patients. Colonoscopic remission was achieved in 57.7% (26 of 45), and histological improvement was noted in 54.1% (20 of 37) of the patients tested. Improved disease activity was demonstrated in 74% (37 of 50) of the patients by general assessment criteria. Analysis of the trial data confirmed the valid clinical efficacy of leukocyte apheresis by centrifugal cell separator in refractory UC patients.

Adult↗

PubMed2005

The fission yeast MO25 protein functions in polar growth and cell separation.

Proteins of the MO25 family are widely conserved but their function has not been characterized in detail. Human MO25 is a cofactor of LKB1, a conserved protein kinase with roles in cell polarity in nematodes, flies and mammalian cells. Furthermore, the budding yeast MO25 homologue, Hym1, is important for cell separation and morphogenesis. We have characterized Pmo25p, the MO25 homologue in the fission yeast Schizosaccharomyces pombe. Pmo25p is an essential protein required for polar growth; in its absence the actin cytoskeleton becomes depolarized and cells adopt a round morphology. In addition, pmo25 mutants are defective in cell separation. Both functions of Pmo25p appear to be mediated by the Orb6p-Mob2p kinase complex. Pmo25p shows no distinct localization during interphase, but it is recruited to one of the two spindle pole bodies during anaphase and to the division site during cytokinesis. The septation initiation network (SIN) regulates the localization of Pmo25p, suggesting that it regulates Pmo25p function during cell division.

Anaphase↗

PubMed1975

Use of cell separation and short-term culture techniques to study erythroid cell development.

Cell populations highly enriched for the different stages of erythroid cell maturation were obtained by three sequential operations: harvesting of erythroid cells after induction of erythroid hyperplasia in the spleens of mice, elimination of the more mature erythrocytes by immunologic techniques, and separation of the residual nucleated erythroid cells as a function of size by the velocity sedimentation technique. The resulting cell fractions were studied both directly and after overnight incubation in the presence or absence of erythropoietin. In short-term culture, erythropoietin stimulated proliferation of pronormoblasts and basophilic normoblasts but probably not cells at later stages of differentiation. Erythropoietin also appeared to recruit increased numbers of pronormoblasts. In this experimental system, erythroid cell differentiation was able to proceed in the absence of erythropoietin, but without proliferation of these early erythroid cells. These techniques have provided a model system for the study of erythroid cells at different stages of maturation isolated from a uniform source at one point in time. The morphologic observations indicated that erythropoietin stimulates erythroid cell proliferation at several early stages of the maturation pathway.

Anemia, Hemolytic↗

PubMed2002

Differential display: analysis of gene expression during plant cell separation processes.

An essential component in the study of cell growth and development in any organism is the analysis of differential gene expression. There are numerous techniques available for comparison of two or more systems at the molecular level, including subtractive hybridization, reverse transcriptase (RT), polymerase chain reaction (PCR), differential screening of cDNA libraries, and, more recently, cDNA microarrays. Differential display has advantages in that it is relatively less time-consuming and can result in the identification of rare cDNA, which may be missed by conventional cDNA library screening. In addition, cDNA microarrays are a valuable asset to the analysis of regulated gene expression but the technique is expensive to employ. Although we successfully applied differential display to isolate novel mRNAs that are up- and downregulated during cell separation processes in plants, the technique can be applied to any system where two or more mRNA sets are to be compared.

Brassica napus↗

PubMed1985

Functional integrity of anterior pituitary cells separated by a density gradient.

Using a continuous Percoll density gradient, endocrine cells of the anterior pituitary were separated. The cells were obtained from adult female Sprague-Dawley rats which had been ovariectomized for 7 days. The gradient revealed two equally sized populations of cells with densities of about 1.02 and 1.09 g/ml. Ninety-two per cent of the cellular GH content, 64% of LH, and 60% of TSH were found in the high density peak. Sixty-one per cent of the cellular Prl appeared in the low density peak. Immunocytochemical staining of the LH containing cells showed that 74% of the gonadotrophs were in the high density peak. After separation, the cells retained their responsiveness to LRH, TRH and GRF. Culture conditions influenced stimulated hormone release. Before stimulation, the cells were cultured either in tissue culture flasks (attached cells) or in Petri dishes (cells in suspension) for 3 days. After TRH-stimulation, suspended thyrotrophs released more TSH than attached thyrotrophs. Comparing the cells of both peaks, attached thyrotrophs of the high density peak showed higher stimulated TSH-release than those of the low density peak. The response of the gonadotrophs and somatotrophs to stimulation did not differ when culture conditions were changed. The present results demonstrate that the secretory activity of endocrine cells is influenced by culture conditions and should be evaluated fore each cell type.

Animals↗

PubMed1977

Glucose-6-phosphate dehydrogenase isoenzymes in acinar epithelial cells separated from the mammary gland of the rat at intervals during the course of lactation.

Acinar epithelial cells were purifed from suspensions of cells from the lactating mammary glands of rats. As described previously, this purififaction was accomplished by sedimentation in an isokinetic gradient of Ficoll (polysucrose) in tissue culture medium, and the purity of the separated cells was established by electron microscopy and by histochemical markers. Isoenzymes of glucose-6-phosphate dehydrogenase were investigated at various intervals during lactation in separated populations of stromal and acinar cells. Acinar cells contained three- to eightfold more glucose-6-phosphate dehydrogenase activity than did stromal cells. The proportions of the respective isoenzymes varied during the course of lactation, and the observed changes were parallel in purified acinar cells and in the lactating mammary glands from which the cell suspensions were obtained. The availability of purified acinar cells in the investigation of interactions between hormones and cells from the mammary gland permits a greater degree of specificity than has been possible in the study of mammary cell suspensions which contain myoepithelial cells, duct cells, acinar cells, endothelial cells, fibroblasts, fat cells, mast cells, plasma cells, and blood cells.

Animals↗

PubMedDate not supplied

Use of a continuous-flow cell separator in density gradient isolation of lymphocytes.

A continuous-flow technique was developed to isolate and concentrate lymphocytes over Ficoll-Hypaque (FH) density gradients using an automated cell separator (Model CS-3000, Fenwal). Lymphocyte concentrates (LC) containing 6.51 X 10(9) mononuclear cells were obtained by standard leukapheresis techniques. Disposable apheresis kits were modified to allow the LC to be pumped into a separation chamber along with a counter-centrifugal flow of saline, removing the platelets and plasma by elutriation. The remaining cells were underlaid with 300 ml of FH, displacing the lymphocytes into a collection bag, where they were washed and concentrated. Mean leukocyte recovery was 59.2 percent (99.9% lymphocytes, n = 14). The final product contained 6.7 percent of the initial platelets and had a hematocrit of less than 1 percent. In paired studies using split leukocyte concentrates (n = 15), lymphocyte recovery obtained by the automated apheresis technique compared favorably with that obtained by standard manual FH gradients (59.8 +/- 3.4% versus 67.3 +/- 4.2%, p greater than 0.05) and platelet contamination was significantly reduced (2.7 +/- 0.5% versus 26.6 +/- 5.7% residual platelets, p less than 0.001). Equivalent lymphokine-activated killer (LAK) activity was generated from cells isolated by both manual and automated techniques. An automated continuous-flow cell separator can be used for rapid FH isolation of large numbers of lymphocytes, providing a sterile product suitable for human use.

Cell Separation↗

PubMed2005

ACE2, CBK1, and BUD4 in budding and cell separation.

Mutations in the RAM network genes, including CBK1, MOB2, KIC1, HYM1, and TAO3, cause defects in bud site selection, asymmetric apical growth, and mating projections. Additionally, these mutants show altered colony morphology, cell separation defects, and reduced CTS1 expression, phenotypes also seen by mutating the Ace2 transcription factor. We show that an ACE2 multicopy plasmid suppresses the latter three defects of RAM network mutations, demonstrating that Ace2 is downstream of the RAM network and suggesting that these phenotypes are caused by reduced expression of Ace2 target genes. We show that wild-type W303 strains have a bud4 mutation and that combining bud4 with either ace2 or cbk1 in haploids results in altered colony morphology. We describe a timed sedimentation assay that allows quantitation of cytokinesis defects and subtle changes in budding pattern and cell shape. Experiments examining budding patterns and sedimentation rates both show that Ace2 and Cbk1 have independent functions in addition to their common pathway in transcription of genes such as CTS1. SWI5 encodes a transcription factor paralogous to ACE2. Additive effects are seen in cbk1 swi5 strains, and we show that activation of some target genes, such as EGT2, requires either Swi5 or Ace2 with Cbk1. The relative roles and interactions of Ace2, Cbk1, and Bud4 in bud site selection, polarized growth, and cell separation are discussed.

Cell Cycle Proteins↗

PubMed1988

Concentration of bone marrow mononuclear cells for in vitro treatment and AB0-incompatible transplantation: a rapid and reproducible procedure using the haemonetics V50 cell separator.

Forty-nine allogeneic and 14 autologous bone marrow grafts were processed with the Haemonetics V50 cell separator (Haemonetics Corp., Braintree, USA) for in vitro treatment with antibodies and cryopreservation respectively. The concentration of hemopoietic progenitor cells was performed without any sedimentation or density gradient agents. The recovery is given in percent (mean +/- sd) of the original marrow values: mononuclear cells (MNC) 74 +/- 10%, polymorphonuclear cells (PMC) 48 +/- 17%, red blood cells (RBC) 12 +/- 5%, granulocyte/monocyte progenitors (CFU-GM) 83 +/- 36%, and erythroid progenitors (BFU-E) 78 +/- 38%. The recovery of nucleated cells (NC) was 90 +/- 13% and the viability 82 +/- 11% after cryopreservation. The technique described provides a simple, rapid and efficient preparation of large bone marrow volumes for in vitro treatment and AB0-incompatible transplantation.

Blood Grouping and Crossmatching↗