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Buffy Coat (buffy + coat)
Selected AbstractsFailure of immunocompetitive capillary electrophoresis assay to detect disease-specific prion protein in buffy coat from humans and chimpanzees with Creutzfeldt-Jakob diseaseELECTROPHORESIS, Issue 5 2003Larisa Cervenakova Abstract The emergence of a new environmentally caused variant of Creutzfeldt-Jakob disease (vCJD), the result of food-born infection by the causative agent of bovine spongiform encephalopathy (BSE), has stimulated research on a practical diagnostic screening test. The immunocompetitive capillary electrophoresis (ICCE) assay has been reported to detect disease-specific, proteinase-resistant prion protein (PrPres) in the blood of scrapie-infected sheep. We have applied this method to blood from CJD-infected chimpanzees and humans. The threshold of detection achieved with our ICCE was 0.6 nM of synthetic peptide corresponding to the prion protein (PrP) C -terminus, and 2 nM of recombinant human PrP at the optimized conditions. However, the test was unable to distinguish between extracts of leucocytes from healthy and CJD-infected chimpanzees, and from healthy human donors and patients affected with various forms of CJD. Thus, the ICCE assay as presently performed is not suitable for use as a screening test in human transmissible spongiform encephalopathies (TSEs). [source] Automated separation of cord blood units in top and bottom bags using the Compomat G4INTERNATIONAL JOURNAL OF LABORATORY HEMATOLOGY, Issue 3 2006P. SOLVES Summary Cord blood (CB) has become a real alternative source of haematopoietic stem cells for bone marrow reconstitution in a variety of malignant disorders. As a response to this increasing activity, CB banks have been developed to guarantee the quality of processed CB units. Volume reduction of CB units maximizes storage space and also has other advantages. The aim of this study was to develop a program for the volume reduction of CB in the Compomat G4 device. We also compared two different top and bottom systems for CB fractionation (Compomat G4 and Optipress II). We empirically designed three different programs for volume reduction of CB with Compomat G4: two for final BC volume of 41 ml (CB1 and CB2) and the other one for buffy coat (BC) volume of 25 ml (CB3). Significantly worse recoveries were achieved for CB processed with program CB3. A RBC depletion of ,50%, ,60% and ,70% were achieved for 67%, 39% and 9% of all units respectively. When comparing Compomat G4 and Optipress II, total nucleated cell recovery was similar for both methods, while lymphocytes recovery was significantly better for Optipress II. [source] Variant Creutzfeldt,Jakob disease and its transmission by bloodJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 7 2003J. W. Ironside Summary., Variant Creutzfeldt,Jakob disease (vCJD) is a novel acquired human prion disease resulting from human exposure to the agent causing bovine spongiform encephalopathy (BSE). vCJD differs from all other human prion diseases in that the disease-associated form of the prion protein and infectivity are present in lymphoid tissues throughout the body. Lymphoid tissues and lymphocytes are implicated in the peripheral pathogenesis of prion diseases (where infectivity may be detected during the preclinical phase of the illness), giving rise to concerns that blood and blood products may also contain infectivity, thus representing a possible source of iatrogenic spread of vCJD. These concerns have been reinforced by the recent transmission of BSE in an experimental sheep model by blood transfusion from an infected animal in the preclinical phase of the illness. Studies in other animal models suggest that most infectivity in blood may be cell-associated, with lower levels in the plasma, and there is evidence to indicate that any infectivity present may be reduced during the process of plasma fractionation. At present, the attempts to detect disease-associated prion protein and infectivity in buffy coat from vCJD patients have been negative, but these studies have been limited in size and in the sensitivity of the detection systems employed. Further studies are required to develop more sensitive means of detection of disease-associated prion protein in blood; such techniques could also be employed for screening purposes, both individually and to help ascertain more precisely the likely numbers of future cases of vCJD. [source] Genetic polymorphisms of cyclooxygenase-2 and colorectal adenoma risk: The Self Defense Forces Health StudyCANCER SCIENCE, Issue 3 2008Naoyuki Ueda Cyclooxygenase (COX) is a key enzyme in the formation of prostaglandins, and an inducible isoform of COX, COX-2, has been implicated in colorectal carcinogenesis. This study investigated the relation of COX-2 polymorphisms (,1195G>A, ,765G>C and 8160A>G) to colorectal adenomas in a case,control study of male officials in the Self Defense Forces (SDF). The study subjects were 455 cases of colorectal adenoma and 1052 controls with no polyps who underwent total colonoscopy. Genotypes were determined using the polymerase chain reaction,restriction fragment length polymorphism (PCR-RFLP) method with genomic DNA extracted from the buffy coat. Statistical adjustment was made for age, hospital, rank in the SDF, body mass index (BMI), cigarette smoking, and alcohol intake. A statistically non-significant decrease in the risk of colorectal adenomas was observed for the AA versus GG genotype of ,1195G>A polymorphism and for the GC versus GG genotype of ,765G>C polymorphism. None had the ,765CC genotype in either the case or control groups. No effect modification of overweight, smoking or alcohol use was observed for either ,1195G>A or ,765G>C polymorphism. The variant allele of the 8160A>G polymorphism was extremely rare. A haplotype of ,1195G, ,765G and 8160A alleles was associated with a modest increase in the risk (adjusted odds ratio [OR] 1.38, 95% confidence interval [CI] 0.99,1.91), and the increase was more evident for distal adenomas (adjusted OR 1.57, 95% CI 1.04,2.38). Another haplotype of ,1195A, ,765C and 8160A alleles showed an adjusted OR of 0.22 (95% CI 0.06,0.88). These findings add to evidence for the role of COX-2 in colorectal carcinogenesis and warrant further studies focusing on haplotypes. (Cancer Sci 2008; 99: 576,581) [source] Extracorporeal photopheresis: what is it and when should it be used?CLINICAL & EXPERIMENTAL DERMATOLOGY, Issue 7 2009J. Scarisbrick Summary Extracorporeal photopheresis (ECP) is a technique that was developed > 20 years ago to treat erythrodermic cutaneous T-cell lymphoma (CTCL). The technique involves removal of peripheral blood, separation of the buffy coat, and photoactivation with a photosensitizer and ultraviolet A irradiation before re-infusion of cells. More than 1000 patients with CTCL have been treated with ECP, with response rates of 31,100%. ECP has been used in a number of other conditions, most widely in the treatment of chronic graft-versus-host disease (cGvHD) with response rates of 29,100%. ECP has also been used in several other autoimmune diseases including acute GVHD, solid organ transplant rejection and Crohn's disease, with some success. ECP is a relatively safe procedure, and side-effects are typically mild and transient. Severe reactions including vasovagal syncope or infections are uncommon. This is very valuable in conditions for which alternative treatments are highly toxic. The mechanism of action of ECP remains elusive. ECP produces a number of immunological changes and in some patients produces immune homeostasis with resultant clinical improvement. ECP is available in seven centres in the UK. Experts from all these centres formed an Expert Photopheresis Group and published the UK consensus statement for ECP in 2008. All centres consider patients with erythrodermic CTCL and steroid-refractory cGvHD for treatment. The National Institute for Health and Clinical Excellence endorsed the use of ECP for CTCL and suggested a need for expansion while recommending its use in specialist centres. ECP is safe, effective, and improves quality of life in erythrodermic CTCL and cGvHD, and should be more widely available for these patients. [source] Performance of the Now Malaria rapid diagnostic test with returned travellers: a 2-year retrospective study in a French teaching hospitalCLINICAL MICROBIOLOGY AND INFECTION, Issue 11 2005F. Durand Abstract Malaria caused by Plasmodium falciparum remains the major life-threatening parasitic infection in the world. The number of cases in non-endemic countries continues to increase, and it is important that misdiagnosis of malaria should not occur, especially in non-immune travellers, because of the high risk of a fatal outcome. In a retrospective study of 399 sera, the Now Malaria rapid test was compared with the quantitative buffy coat (QBC) test and microbiological examination of thin blood films. Compared with the QBC test and thin blood films, the Now Malaria test had sensitivity and specificity values of 96.4% and 97%, respectively, for the detection of pure P. falciparum infection. A negative predictive value of 99.4% allows this test to be included in diagnostic strategies for patients presenting with clinical suspicion of malaria. Two false-negative results were associated with low levels of parasitaemia in the specimens. Thus, use of the Now Malaria test alone to detect P. falciparum infection in non-endemic countries could lead to misdiagnosis of malaria. This rapid diagnostic test should therefore be performed in association with another prompt traditional method such as examination of thin blood films. [source] Optimization of an enrichment process for circulating tumor cells from the blood of head and neck cancer patients through depletion of normal cellsBIOTECHNOLOGY & BIOENGINEERING, Issue 2 2009Liying Yang Abstract The optimization of a purely negative depletion, enrichment process for circulating tumor cells (CTCs) in the peripheral blood of head and neck cancer patients is presented. The enrichment process uses a red cell lysis step followed by immunomagnetic labeling, and subsequent depletion, of CD45 positive cells. A number of relevant variables are quantified, or attempted to be quantified, which control the performance of the enrichment process. Six different immunomagnetic labeling combinations were evaluated as well as the significant difference in performance with respect to the blood source: buffy coats purchased from the Red Cross, fresh, peripheral blood from normal donors, and fresh peripheral blood from human cancer patients. After optimization, the process is able to reduce the number of normal blood cells in a cancer patient's blood from 4.05,×,109 to 8.04,×,103 cells/mL and still recover, on average, 2.32 CTC per mL of blood. For all of the cancer patient blood samples tested in which CTC were detected (20 out of 26 patients) the average recovery of CTCs was 21.7 per mL of blood, with a range of 282 to 0.53 CTC. Since the initial number of CTC in a patient's blood is unknown, and most probably varies from patient to patient, the recovery of the CTC is unknown. However, spiking studies of a cancer cell line into normal blood, and subsequent enrichment using the optimized protocol indicated an average recovery of approximately 83%. Unlike a majority of other published studies, this study focused on quantifying as many factors as possible to facilitate both the optimization of the process as well as provide information for current and future performance comparisons. The authors are not aware any other reported study which has achieved the performance reported here (a 5.66 log10) in a purely negative enrichment mode of operation. Such a mode of operation of an enrichment process provides significant flexibility in that it has no bias with respect to what attributes define a CTC; thereby allowing the researcher or clinician to use any maker they choose to define whether the final, enrich product contains CTCs or other cell type relevant to the specific question (i.e., does the CTC have predominately epithelial or mesenchymal characteristics?). Biotechnol. Bioeng. 2009;102: 521,534. © 2008 Wiley Periodicals, Inc. [source] | |||||||||||||