Storage of cord blood attracts private-sector interest.
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Storage of cord blood from their babies can cost parents several hundred dollars, and some private companies are already offering the service. Janis Hass reports that some Canadian specialists question the value of the banks. (+info)
Freezer anthropology: new uses for old blood.
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Archived blood fractions (plasma, settled red cells, white cells) have proved to be a rich and valuable source of DNA for human genetic studies. Large numbers of such samples were collected between 1960 and the present for protein and blood group studies, many of which are languishing in freezers or have already been discarded. More are discarded each year because the usefulness of these samples is not widely understood. Data from DNA derived from 10-35-year-old blood samples have been used to address the peopling of the New World and of the Pacific. Mitochondrial DNA haplotypes from studies using this source DNA support a single wave of migration into the New World (or a single source population for the New World), and that Mongolia was the likely source of the founding population. Data from Melanesia have shown that Polynesians are recent immigrants into the Pacific and did not arise from Melanesia. (+info)
Correlation of cytokine elaboration with mononuclear cell adhesion to platelet storage bag plastic polymers: a pilot study.
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The basis for many febrile nonhemolytic transfusion reactions associated with platelet transfusion therapy is cytokine elaboration and accumulation in the storage bag, which correlate with the leukocyte content and the length of platelet storage. We propose that a possible additional variable in the elaboration and accumulation of cytokines is the differential adhesion of mononuclear cells to the plastic substrate of the platelet storage bag. We hypothesize that mononuclear cell adhesion-induced cytokine release is greater in random-donor platelet bags composed of the polyolefin polymer compared to the single-donor apheresis platelet bags composed of the polyvinyl chloride polymer with the tri-(2-ethylhexyl) trimellitate (TEHTM) plasticizer. For four blood donors, we demonstrate preferential mononuclear cell adhesion, in vitro, to discs of polyolefin polymer versus discs of polyvinyl chloride polymer with the TEHTM plasticizer. Scanning electron microscopy corroborates this. In addition, proinflammatory cytokine (interleukin 1beta [IL-1beta] and tumor necrosis factor alpha [TNF-alpha]) levels are greater in culture wells containing discs of polyolefin polymer than in those containing discs of polyvinyl chloride polymer with the TEHTM plasticizer, and even more so in storage bags containing polyolefin polymer versus polyvinyl chloride polymer with the TEHTM plasticizer (IL-1beta, TNF-alpha, IL-6, and IL-8). This study suggests, for the first time, that differential plastic substrate mononuclear cell adhesion may contribute to cytokine release during platelet storage. This may represent an additional variable in the pathophysiology of febrile nonhemolytic transfusion reactions in patients receiving stored platelet units. (+info)
Heat treatment of normal human sera reveals antibodies to bactericidal permeability-inducing protein (BPI).
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Heat treatment of normal sera to 56 degrees C for 30 min, a common procedure for the inactivation of viruses, e.g. HIV, reveals the presence of antibodies to neutrophil cytoplasm antigens (ANCA), as detected by indirect immunofluorescence on ethanol-fixed human neutrophils and by antigen-specific ELISA for BPI. Reactivity was not seen to the other common vasculitis-associated antigens proteinase 3 (PR3) or myeloperoxidase (MPO). The effect of temperature was maximal at 56 degrees C, with substantial antibody demonstrable after only 5 min at this temperature. In experiments using polyethylene glycol (PEG)6000 to remove immune complexes, the effect of heating could be abrogated by preincubation with 8% PEG, which suggested that these anti BPI antibodies might be complexed in sera. After passage of normal plasma over a protein G column, the acid-eluted fraction contained elevated levels of antibodies to BPI but not to other vasculitis-associated antigens such as PR3 or MPO, nor to glomerular basement membrane (GBM), the Goodpasture antigen which is recognized by the pathogenically important human antibodies shown to mediate nephritis in transfer experiments. Moreover the levels of anti-BPI in the IgG fraction could be augmented by preincubation with glycine pH 2.5 for 30 min. This anti-BPI activity could be inhibited by addition of the unbound material from the protein G column and this inhibitory material was not heat-labile at 56 degrees C. The molecular specificity of this autoreactivity was confirmed using recombinant BPI in coincubation experiments and the epitope localized to the C or N terminal moieties by the use of recombinant fusion proteins. (+info)
Monitoring oral anticoagulant treatment from plasma stored for up to 48 hours and frozen plasma.
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BACKGROUND AND OBJECTIVE: The number of patients being referred for lifelong anticoagulant treatment has increased markedly in the last years. The prothrombin time test is sometimes difficult to perform the same day as sample collection. The aim of this study is to determine International Normalized Ratio (INR) and vitamin-K dependent factor levels of frozen plasma and plasma stored for up 48 hours. DESIGN AND METHODS: The INR of 84 patients receiving acenocoumarol were determined fresh (0 hours), on samples stored between 2 degrees C and 8 degrees C for 24 hours and 48 hours, and on frozen samples (-40 degrees C) using 4 different thromboplastin reagents (Thromboplastin IS; Thromborel; Simplastin; and Thromboplastin D+G). In addition, factors II, VII, IX, X were determined in 34 of these patients in all these situations. We used the interclass correlation coefficient to compare the results obtained at 0 hours and the results obtained in the subsequent measurements. Both measurement and proportional errors were also estimated by linear regression analysis. RESULTS: The correlation coefficient of the INR between fresh and frozen plasma was 0.98, 0.98, 0.92 and 0.97 for IS, Thromborel, Simplastin and D+G respectively. The correlation between 0 and 24 hours was 0. 98, 0.91, 0.95 and 0.85 for IS, Thromborel, Simplastin and D+G respectively. By 48 hours although IS still had r=0.94, Thromborel, Simplastin, and D+G had r=0.55, r=0.50 and r=0.81, respectively. By 24 hours in stored plasma and in frozen plasma the activity of vitamin-K dependent factors was slightly reduced (r=0.97 at 24h/r=0. 94 with frozen plasma for factor II, r=0.92/0.96 for factor VII, r=0. 83/0.98 for factor IX, and r=0.98/0.95 for factor X). By 48 hours however, significant reductions were noted in the activity of these factors (r=0.94 for factor II, r=0.88 for factor VII, r=0.70 for factor IX, and r=0.98 for factor X). INTERPRETATION AND CONCLUSIONS: The INR can be reliable determined in frozen plasma and in plasma stored at 2-8 degrees C for up to 24 hours. (+info)
Assessment of the stability of N-terminal pro-brain natriuretic peptide in vitro: implications for assessment of left ventricular dysfunction.
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Plasma concentrations of N-terminal pro-brain natriuretic peptide (NT-proBNP) are raised in patients with left ventricular dysfunction. Measurement of this peptide has a potential diagnostic role in the identification and assessment of patients with heart failure. The stability of this peptide over time periods and conditions pertaining to routine clinical practice has not been reported previously. Blood samples were obtained from 15 subjects. One aliquot was processed immediately, and the remaining portions of the blood samples were stored for 24 h or 48 h at room temperature or on ice prior to processing. Plasma concentrations of NT-proBNP were measured with a novel immunoluminometric assay developed within our laboratory. Mean plasma concentrations of NT-proBNP were not significantly different whether blood samples were centrifuged immediately and stored at -70 degrees C or kept at room temperature or on ice for 24 h or 48 h. The mean percentage differences from baseline (reference standard) were +5.2% (95% confidence interval +18.2 to -7.8%) and +0.8% (+15.2 to -13.7%) after storage for 24 h at room temperature or on ice respectively, and +8.9% (+24.2 to -6. 5%) and +3.2% (+15.1 to -0.9%) for storage for 48 h at room temperature or on ice respectively. Pearson correlation coefficients for baseline NT-proBNP concentrations compared with levels at 48 h at room temperature or on ice were r=0.89 and r=0.83 respectively (both P<0.0001). Thus NT-proBNP extracted from plasma samples treated with EDTA and aprotinin is stable under conditions relevant to clinical practice. (+info)
Preanalytical variables affecting the quantification of fatty acid ethyl esters in plasma and serum samples.
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BACKGROUND: Fatty acid ethyl esters (FAEEs) are cytotoxic nonoxidative ethanol metabolites produced by esterification of fatty acids and ethanol. FAEEs are detectable in blood up to 24 h after ethanol consumption. The objective of this study was to assess the impact of gender, serum or plasma triglyceride concentration, time and temperature of specimen storage, type of alcoholic beverage ingested, and the rate of ethanol consumption on FAEE concentrations in plasma or serum. METHODS: For some studies, subject were recruited volunteers; in others, residual blood samples after ethanol quantification were used. FAEEs were isolated by solid-phase extraction and quantified by gas chromatography-mass spectrometry. RESULTS: For weight-adjusted amounts of ethanol intake, FAEE concentrations were twofold greater for men than women (P /=24 h. The type of alcoholic beverage and rate of consumption did not affect FAEE concentrations. CONCLUSION: These studies advance plasma and serum FAEE measurements closer to implementation as a clinical test for ethanol intake. (+info)
Increased serum transferrin saturation is associated with lower serum transferrin receptor concentration.
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BACKGROUND: Serum transferrin receptor (sTfR) concentrations are increased in iron deficiency. We wished to examine whether they are decreased in the presence of potential iron-loading conditions, as reflected by increased transferrin saturation (TS) on a single occasion. METHODS: We compared sTfR concentrations between 570 controls with normal iron status and 189 cases with increased serum TS on a single occasion; these latter individuals may be potential cases of iron overload. Cases and controls were selected from adults who had been examined in the third National Health and Nutrition Examination Survey (1988-1994) and for whom excess sera were available to perform sTfR measurements after the survey's completion. Increased TS was defined as >60% for men and >55% for women; normal iron status was defined as having no evidence of iron deficiency, iron overload, or inflammation indicated by serum ferritin, TS, erythrocyte protoporphyrin, and C-reactive protein. RESULTS: Mean sTfR and mean log sTfR:ferritin were approximately 10% and 24% lower, respectively, in cases than in controls (P <0.002). Cases were significantly more likely to have an sTfR value <2.9 mg/L, the lower limit of the reference interval, than were controls (odds ratio = 1.8; 95% confidence interval, 1.04-2.37). CONCLUSION: Our results support previous studies that suggested that sTfR may be useful for assessing high iron status in populations. (+info)