bluuebunny/crossref_metadata_2025_split huggingface dataset:
Concentration of citrate anticoagulant in peripheral blood progenitor cell collections
Authors: Burger S.R. , Fautsch S.K. , Stroncek D.F. , McCullough J. 
Published: March 2003

Background: Peripheral blood progenitor cell (PBPC) collection by hemapheresis has become widely used in recent years. For anticoagulation during cytapheresis, citrate solutions, commonly ACD‐A, are used, at a recommended anticoagulant‐to‐whole blood ratio of 1:11 to 1:12. Although the apheresis procedure is generally well tolerated, the most common patient complaints are attributable to transient hypocalcemia, which is a side effect of the citrate anticoagulant. Patients experiencing discomfort due to hypocalcemia are sometimes managed by a decrease in the flow rate of the anticoagulant. Case Reports: Two cases are reported in which seemingly minor reductions in the anticoagulant: whole blood ratio appeared to cause gelation of freezing solution prepared from plasma that was collected in addition to PBPCs for use in the cryopreservation of cells. In both cases, the final ratio of citrate anticoagulant to whole blood was less than 1:12. Gelation occurred when plasma collected under these conditions was used to prepare freezing solution. Conclusion: The addition of heparin to this plasma, or the addition of ACD‐A to correct the anticoagulant:whole blood ratio, prevented the gelation of freezing solution, which suggests that coagulation activation in the autologous plasma specimen was implicated in the subsequent gelation. During cytapheresis for PBPC collection, citrate‐containing anticoagulants should be used at the recommended ratio of 1:12, or with more anticoagulant than usual. Tolerance for a reduced concentration of citrate may be more limited than is generally appreciated. When plasma is collected in addition to PBPCs, heparin should be added to both the cells and the plasma as soon as possible after the collection. Patients undergoing PBPC and stem cell collection should be given supplemental calcium, rather than less anticoagulant, to alleviate the discomfort associated with citrate.
Automatic volumetric capillary cytometry for counting white cells in white cell‐reduced plateletpheresis components
Authors: Adams M.R. , Johnson D.K. , Busch M.P. , Schembri C.T. , Hartz T.P. , Heaton W.A. 
Published: March 2003

BACKGROUND: As the benefits of white cell (WBC)‐reduced blood components become increasingly apparent, the need has arisen for a simple, automated WBC‐counting technique that is sensitive to low WBC concentrations. Automated volumetric capillary cytometry was evaluated for its ability to quantify residual WBCs in WBC‐reduced plateletpheresis components.STUDY DESIGN AND METHODS: The volumetric capillary cytometry system evaluated uses a laser to excite fluorescent dye‐labeled nucleated cells. The number of nucleated cells per μL is reported. Four studies were performed: linearity, precision of results near the value of 5 × 106 WBCs per unit, the limit of detection, and correlation to the Nageotte manual counting method.RESULTS: Assay values correlated to expected values (range, 0–125 WBC/μL) with an r2 > 0.99. In the range of 5 × 106 WBCs per unit the CV was 8.5 percent, and concentration differences of 0.15 log10 were detectable. The limit of detection was 1.0 WBCs per microliter (95% upper confidence limit). The assay correlated to the Nageotte method with an r2 of 0.98, slope of 1.0, and y‐intercept of 2.0 WBCs per μL. Assay results were 10 to 15 percent higher than Nageotte results, in samples with values near 5 × 106 WBCs per unit. Technician time per sample was 2 to 3 minutes.CONCLUSION: Volumetric capillary cytometry is precise and sensitive to small differences in WBC concentration in the range of clinical interest. The device provides an efficient new method for quality assurance and control of WBC‐reduced plateletpheresis products.
Expression of blood group i antigen and fetal hemoglobin in paroxysmal nocturnal hemoglobinuria
Authors: Navenot J.‐M. , Mullet J.‐Y. , Blanchard D. 
Published: March 2003

BACKGROUND: The mechanism by which the paroxysmal nocturnal hemoglobinuria (PNH) clone progressively takes over normal hematopoietic cells remains unknown. The respective in vivo differentiation of normal and PNH erythroid progenitors was investigated through the expression of two fetal erythroid markers (i antigen and fetal hemoglobin [HbF]) whose expression in adult red cells is associated with altered erythropoiesis.STUDY DESIGN AND METHODS: Murine monoclonal antibodies directed against HbF and i and CD59 antigens were used to phenotype red cells of 10 PNH patients. A multiparametric flow cytometry assay of red cells and reticulocytes was designed to assess a possible association of i and HbF with PNH or normal red cells.RESULTS: Most patients exhibited greater expression of i and HbF than did normal controls. In each case, the percentages of i‐positive or HbF‐positive cells within CD59‐deficient and CD59‐positive red cells were very close, clearly showing a lack of preferential association of these markers with normal or PNH cells.CONCLUSION: In PNH patients, normal and PNH erythroid progenitors have the same ability to promote HbF and i antigen expression, which suggests that normal and PNH erythroid progenitors (burst‐forming units–erythroid, colony‐forming units–erythroid, erythroblasts) behave similarly in response to bone marrow stress.
Removing IgG antibodies from intact red cells: comparison of acid and EDTA, heat, and chloroquine elution methods
Authors: des Roziers N. Burin , Squalli S. 
Published: March 2003

BACKGROUND: To accurately phenotype red cell from patients with a positive direct antiglobulin test (DAT), nonlytic elution procedures were assessed for their ability to dissociate IgG from antibody‐coated red cells without altering red cell antigen expression.STUDY DESIGN AND METHODS: Antibodies coating red cells that were sensitized in vivo (warm‐reactive autoantibodies: 8 patients) or in vitro (42 alloantibodies) were eluted by using glycine‐HCl and EDTA (acid/EDTA), heat (56°C, 10 min), or chloroquine method.RESULTS: Acid/EDTA elution gave the best results, reducing DAT positivity to microscopic levels or rendering the DAT negative in 48 of 50 instances, whereas 4 samples remained resistant to heat elution and 24 to chloroquine. Standard DAT agglutination scores demonstrated that both acid/EDTA and heat elution were superior to the chloroquine method (p < 0.0001). With the gel low‐ionic‐strength saline indirect antiglobulin test, acid/ EDTA was superior to heat (p < 0.001). Overall, acid/ EDTA elution dissociated more antibodies than heat (p < 0.0001), especially for Kell system (K, k, Kpa, Kpb) alloantibodies. Common red cell antigens, other than Kell system antigens, were unaffected by acid/EDTA elution. In contrast, the expression of most blood group antigens was diminished after heat elution. However, it was possible to type red cell antigens by using gel low‐ionic‐strength saline indirect antiglobulin tests or tube agglutination methods.CONCLUSION: Although heat elution may be used on a limited basis, the acid/EDTA method appears to be the procedure of choice for typing red cell coated with warm‐reactive IgG alloantibodies or autoantibodies.
Detection and differentiation of platelet‐specific antibodies by flow cytometry: the bead‐mediated platelet assay
Authors: Helmberg W. , Fölsch B. , Wagner T. , Lanzer G. 
Published: March 2003

BACKGROUND: Platelet‐reactive antibodies cause a number of clinical disorders. The detection and differentiation of these antibodies are prerequisites for the adequate treatment of these disorders. The bead‐ mediated platelet assay described here enables the detection and differentiation of platelet‐bound antibodies by the use of flow cytometry.STUDY DESIGN AND METHODS: The bead‐mediated platelet assay is based on the isolation of human platelet glycoproteins by using flow cytometric standardization beads after the incubation of typed platelets with human sera. The specificity and sensitivity of this assay were tested with five sera, each containing a known platelet‐ reactive antibody. The monoclonal antibody‐specific immobilization of platelet antigens assay was used as a reference test.RESULTS: The bead‐ mediated platelet assay was able to determine the glycoprotein specificity of the antibody without cross‐reactions in every case. In serial dilution tests, the bead‐mediated platelet assay was able to detect the antibodies at higher dilutions than the monoclonal antibody‐ specific immobilization of platelet antigen assay. Total test time was 3.5 hours.CONCLUSION: The bead‐mediated platelet assay is a fast and reliable method for the detection and differentiation of platelet‐ reactive antibodies.
Factors affecting mobilization of CD34+ cells in normal donors treated with filgrastim
Authors: Anderlini P. , Przepiorka D. , Seong C. , Smith T.L. , Huh Y.O. , Lauppe J. , Champlin R. , Körbling M. 
Published: March 2003

BACKGROUND: Multiple days of apheresis are required for some normal peripheral blood progenitor cell (PBPC) donors, to ensure a sufficient collection of CD34+ cells for allografting. It would be of practical value to be able to identify the patients with poor mobilization on the basis of simple pretreatment clinical or hematologic variables.STUDY DESIGN AND METHODS: Clinical characteristics and laboratory data for 119 normal PBPC donors who underwent apheresis on Days 4 to 6 of treatment with granulocyte‐colony‐stimulating factor (filgrastim) were analyzed for correlations with CD34+ cell yield from the first day of apheresis.RESULTS: The CD34+ cell yield was significantly lower in donors who were more than 55 years of age, who underwent apheresis on Day 4 of filgrastim therapy, or who were not obese. There were weak direct correlations between CD34+ cell yield and the baseline white cell count, preapheresis white cell count, and preapheresis mononuclear cell count, and there was a weak inverse correlation with age. Twenty‐ one donors (18%) were considered to have poor mobilization (< 20 × 106 CD34+ cells/L blood processed). In the multivariate analysis, the only significant factor was age greater than 55 years, which conferred a 3.8 times greater risk (95% CI, 1.1–13.7) of poor mobilization (p = 0.04). However, poor mobilization occurred in all age groups, so the predictive value of the model was low.CONCLUSION: Donor variables correlated with CD34+ cell yield only weakly, so no particular clinical characteristic can be used to exclude an individual as a PBPC donor if he or she is otherwise suitable for the apheresis procedure.
Perioperative myocardial ischemic episodes are related to hematocrit level in patients undergoing radical prostatectomy
Authors: Hogue C. W. , Goodnough L. T. , Monk T. G. 
Published: March 2003

BACKGROUND: The anemia associated with perioperative blood conservation has raised concerns regarding the safety of these strategies in patients with ischemic cardiovascular disease. Therefore the relationship between hematocrit level and myocardial ischemic episodes in a group of elderly patients undergoing elective noncardiac surgery was studied.STUDY DESIGN AND METHODS: One hundred ninety patients undergoing radical prostatectomy were randomly assigned to one of three blood conservation groups: preoperative autologous blood donation, acute normovolemic hemodilution, and preoperative erythropoietin therapy with acute normovolemic hemodilution. Patients underwent ambulatory electrocardiography monitoring to evaluate for myocardial ischemia at randomization (baseline), 7 days preoperatively, throughout surgery, and for 24 hours after surgery.RESULTS: Myocardial ischemic episodes occurred in 61 (34%) of 181 evaluable patients. Patients with hematocrit levels < 28 percent immediately after surgery were significantly (p = 0.05) more likely to have intraoperative and postoperative ECG ischemic episodes. Intraoperative ischemia and tachycardia correlated (r = 0.21, p = 0.008) with hematocrit levels. Hematocrit levels after surgery were associated with postoperative ischemia (r = 0.14, p = 0.03) and duration of myocardial ischemic episodes (r = 0.14, p = 0.04). After adjusting for other risk factors, intraoperative tachycardia episodes, hematocrit level < 28 percent immediately after surgery, and risk factors for coronary artery disease were independently associated with the likelihood of intraoperative ischemia (r = 0.36, p = 0.002, area under receiver operating characteristic curve = 0.73). Similarly, tachycardia episodes and hematocrit levels < 28 percent immediately after surgery were independently associated with ischemic episodes during the first postoperative day (r = 0.30, p = 0.004, area under receiver operating characteristic curve = 0.71).CONCLUSION: A hematocrit level < 28 percent is independently associated with risk for myocardial ischemia during and after noncardiac surgery. Avoidance of cardiac complications may require higher transfusion thresholds, closer attention to tachycardia, or better monitoring for ischemia.
A multi‐laboratory evaluation of in vitro platelet assays: the tests for extent of shape change and response to hypotonic shock. Biomedical Excellence for Safer Transfusion Working Party of the International Society of Blood Transfusion
Authors: S. Holme PhD Scientific Director  , G. Moron PhD Senior Scientist  , S. Murphy MD Chief Medical Officer  
Published: March 2003

BACKGROUND: There is no consensus regarding the use of specific in vitro tests for the assessment of the quality of platelet components. A literature review found that the platelet discoid shape as measured photometrically by the extent of shape change (ESC) and hypotonic shock response (HSR) correlated well with in vivo viability. The purpose of this study was to determine whether multiple research laboratories can perform the ESC and HSR assays in an accurate, reproducible manner, with acceptable sensitivity and comparable results.STUDY DESIGN AND METHODS: Eleven laboratories conducted five identical experiments, each with a different unit of platelet‐rich plasma (PRP). For each experiment, 2 half‐units of PRP were prepared and stored overnight: 1 half‐unit at 20 to 24 degrees C in CPD (CPD‐PRP) and the other at 1 to 6 degrees C with 2 mg per mL of EDTA (cold EDTA‐PRP) added to produce spherical platelets with reduced HSR. Platelet suspensions having different proportions of the two PRPs were prepared and evaluated in duplicate by ESC and HSR assays, and morphologically scored by microscopy. One‐way ANOVA and Duncan multiple‐range tests were performed to determine significant differences in assay results for suspensions having different proportions of CPD‐PRP.RESULTS: Comparable ESC (mean range: 20–28% for CPD‐PRP and 1–6% for cold EDTA‐ PRP) and HSR (mean range: 58–81% for CPD‐PRP and 12–31% for cold EDTA‐ PRP) measurements were obtained by nine laboratories. Duplicate testing showed high reproducibility of ESR and HSR results /in all laboratories. A 25‐percent difference in the proportion of CPD‐PRP (indicative of a difference of approximately 25% in the proportions of discoid and spherical platelets) was detected with a sample size of five (p<0.05) for both the ESC and HSR assays. A high correlation was found for the ESC assay and morphology score (r = 0.93, n = 345). CONCLUSION: Multiple laboratories were able to obtain comparable results with the ESC and HSR tests. They were able to show that the tests can be performed in an accurate, reproducible manner and with acceptable sensitivity.
Clinical utility of plasma membrane vesicles expressing recombinant glycophorin A‐encoded blood group antigens
Authors: Donnell M.E. , Martin A.L. , Blackall D.P. 
Published: March 2003

BACKGROUND:Although the genes encoding most of the major blood group determinants are now cloned, recombinant blood group antigens are not commonly used in the clinical laboratory. This study assessed the feasibility of using plasma membrane vesicles expressing recombinant glycophorin A blood group antigens as soluble immunoadsorbants.STUDY DESIGN AND METHODS:Chinese hamster ovary cells were transfected with plasmids containing the cDNA encoding the M‐ or N‐allele of glycophorin A. Plasma membrane vesicles were chemically induced from stable, high‐ expressing cell lines. Antibodies were assessed for reactivity in hemagglutination‐inhibition assays.RESULTS:Eight anti‐M antibodies were evaluated. Vesicles expressing the M‐allele of glycophorin A neutralized four antibodies (two murine monoclonals; two human sera), while the activity of four human sera was unaffected. Three anti‐N reagents were also evaluated (murine monoclonal antibody; rabbit polyclonal antibody; Vicia graminea lectin). All were neutralized by vesicles expressing the N‐allele of glycophorin A. There was no detectable neutralization of other clinically significant blood group antibodies.CONCLUSIONS:Plasma membrane vesicles expressing recombinant glycophorin blood group determinants may prove to be useful reagents in the clinical laboratory. However, the partial failure of M antibody recognition requires further study. This general approach could be utilized for any similarly expressed recombinant blood group antigen.
Clinical factors influencing posttransfusion platelet increment in patients undergoing hematopoietic progenitor cell transplantation—a prospective analysis
Authors: Ishida A. , Handa M. , Wakui M. , Okamoto S. , Kamakura M. , Ikeda Y. 
Published: March 2003

BACKGROUND: Platelet transfusion refractoriness remains problematic in the management of patients who have undergone hematopoietic progenitor cell transplantation. Bone marrow transplantation itself is reported to be a relevant factor hampering efficient platelet transfusions. However, a prospective analysis assessing factors affecting platelet transfusion efficacy in the setting of hematopoietic progenitor cell transplantation has yet to be conducted.STUDY DESIGN AND METHODS: To identify factors independently influencing platelet transfusion efficacy after hematopoietic progenitor cell transplantation, a prospective study was performed to determine the effectiveness of platelet transfusions by estimating posttransfusion (16‐hour) corrected count increments (CCI) in 42 consecutive patients (26 who received allogeneic transplants and 16 who received autologous transplants) with 439 available platelet transfusions.RESULTS: The mean CCI and percentage of CCI <4500 for all transfusions were 6161.1 +/− 7775.2 per microL and 42.1 percent, respectively. Multiple linear regression analyses revealed high total bilirubin, total body irradiation, high serum tacrolimus, and high serum cyclosporin A to be major factors independently predicting a lower CCI. HLA antibodies with restricted specificity and platelet antibodies were detected transiently in 17 and 14 percent of the patients, respectively. The presence of these antibodies was not, however, associated with a poor response to platelet transfusions.CONCLUSION: Platelet transfusion efficacy in hematopoietic progenitor cell transplant recipients is markedly influenced by clinical factors specific to the procedure as well as those already recognized in other settings. Alloimmunization is not, however, a major factor associated with a poor response to platelet transfusions after this procedure.
Clinical evaluation of a staphylococcal protein A immunoadsorption system in the treatment of myasthenia gravis patients
Authors: Benny W.B. , Sutton D.M.C. , Oger J. , Bril V. , McAteer M.J. , Rock G. 
Published: March 2003

BACKGROUND: The role of plasma exchange is well established in the management of myasthenia gravis, an autoimmune disorder characterized by muscle weakness and caused by circulating IgG antibodies with specificity against the acetylcholine receptor. Plasma antibody removal by conventional means, however, is nonselective and uses replacement fluids (chiefly, albumin solution) derived from human plasma.STUDY DESIGN AND METHODS: The Canadian Apheresis Group undertook a study at two Canadian apheresis centers to clinically evaluate a staphylococcal protein A immunoadsorption system (EXCORIM) in myasthenia gravis patients.RESULTS: The immunoadsorption system was safe and well tolerated. Ten of 12 patients had improvement in their neurologic status, as measured by a 20‐point scoring system. The mean improvement in the weakness score was significant for the group (p = 0.0013).CONCLUSION: Patients with myasthenia gravis respond to treatment with plasma immunoadsorption. Further studies are required for a cost‐benefit analysis.
Severe delayed hemolytic transfusion reaction secondary to anti‐Ata
Authors: Cash K.L. , Brown T. , Sausais L. , Uehlinger J. , Reed L.J. 
Published: March 2003

BACKGROUND: Anti‐Ata is a rare red cell (RBC) alloantibody found in the black population. It has been described as causing one case of mild hemolytic disease of the newborn, but its ability to cause hemolytic transfusion reactions is uncertain.CASE REPORT: The patient was a 60‐year‐old black female with a history of three uneventful pregnancies but no transfusions. On admission, her direct and indirect antiglobulin tests were negative, total bilirubin was 0.5 mg per dL, and lactate dehydrogenase was 224 IU per L. She received nine units of compatible RBCs in the perioperative period of a hemicolectomy. Her hemoglobin rose appropriately and stabilized at 12.6 g per dL by the 6th postoperative day. By Day 10 after surgery her hemoglobin had dropped to 6.8 g per dL, and her total bilirubin and lactate dehydrogenase had risen to 1.4 mg per dL and 783 IU per L, respectively. The direct and indirect antiglobulin tests were now newly positive with strengths of 3+. A warm hemolytic autoantibody was suspected. She was transfused two units of incompatible RBCs for a rapidly falling hemoglobin and symptomatic anemia. On Day 11, the total bilirubin rose to 3.5 mg per dL, and the lactate dehydrogenase was 1154 IU per L with a hemoglobin of 7.6 g per dL. Corticosteroids were begun. Studies of serum and an acid eluate revealed anti‐Ata, but no other RBC antibodies. The patient stabilized, and further transfusion was avoided.CONCLUSION: Although anti‐Ata was previously described as being of uncertain clinical significance, this patient demonstrated the ability of the antibody to cause a severe delayed hemolytic transfusion reaction.