Efficacy of autologous fresh whole blood or platelet-rich plasma in adult cardiac surgery

BACKGROUND: Transfusing fresh autologous blood during cardiac surgery may improve hemostasis and decrease the need for transfusion. STUDY DESIGN AND METHODS: A prospective randomized study was performed with fresh whole blood (WB) obtained by intraoperative hemodilution (IH) and with platelet-rich plasma (PRP) obtained by perioperative apheresis from adult cardiac surgery patients. RESULTS: Seventy patients were randomly assigned to three arms: 24 to the PRP arm, 18 to the IH arm, and 28 to serve as controls. A mean of 924 +/− 130 mL of WB was collected from the IH group, and a mean of 650 +/− 124 mL of PRP was collected from the PRP group (mean, 1.42 +/− 0.74 × 10(11) platelets); these components were transfused after bypass. Preoperative measures were similar among groups. Intraoperatively, the groups did not differ in bypass time, estimated blood loss, number of transfusions, or proportion receiving transfusion(s). Postoperatively, control patients had more mediastinal drainage (736 mL vs. 476 mL [IH] and 463 mL [PRP]; p = 0.014), but there was no difference in the proportion of patients requiring red cell transfusion (p = 0.87), the hemoglobin at discharge (p = 0.20), or the length of hospitalization (p = 0.57). CONCLUSION: Although a hemostatic benefit manifested as reduced postoperative bleeding was observed, this study does not support the use of fresh blood components obtained by IH or PRP collection during low-risk cardiac surgery. Additional studies are needed to assess whether more aggressive component collection or the use of these techniques in high- risk cases may have a greater impact on clinical outcome variables, including transfusion.     

A flow cytometric method for phenotyping recipient red cells following transfusion

BACKGROUND: Reticulocyte phenotyping is used for transfused patients, who have red cell antibodies, to match blood for subsequent transfusion. Current methods are labor-intensive and require a significant amount of sample. STUDY DESIGN AND METHODS: A simple dual- color flow cytometry method developed for antigen typing of reticulocytes in mixed red cell populations is reported. Antigens were labeled by an indirect immunofluorescence technique using undiluted reagent sera as the primary label, biotinylated goat anti-human IgG as the secondary label, and avidin-phycoerythrin as the fluorescent stain. Reticulocytes were labeled with a thiazole orange fluorescent stain. Reticulocyte identification and antigen typing were performed on 319 samples to establish the validity of the procedure. Mixed red cells were prepared in all possible c antigen combinations to simulate transfusion concentrations of 25, 50, and 75 percent. RESULTS: The anti- c flow cytometry profiles readily distinguished between antigen- positive and antigen-negative populations and allowed the detection of reticulocytes at all simulated transfusion concentrations. Similar results were obtained in experiments using C, K, s, Fya, Fyb, Jka, or Jkb sera against equal volumes of antigen-positive and -negative cells. Anti-S gave inconsistent results. The in vitro results were confirmed in 19 transfused patients who had received red cells antigenically different from their own as well as cells from 1 chimera blood donor. CONCLUSION: This method provides a simpler, safer, less labor- intensive, and less subjective technique requiring far less sample volume than current methods for antigen typing of reticulocytes in mixed red cell samples from recently transfused patients.     

Radiation shielding in dentistry: an update

The purpose of this article was to review the literature and provide guidelines on the use of radiation protection for patients in the dental setting. There are limited published data on the effects of low radiation doses such as those used in dental radiology. Most of the evidence is subject to bias, with risk models extrapolated from higher dose models such as studies of the Hiroshima bomb survivors. However, the lack of evidence does not denote the absence of risk, as there is no established ‘safe’ level of radiation exposure. All imaging utilizing ionizing radiation carries a risk for the patient. Hence the patient benefits of imaging must outweigh the potential risk. All diagnostic imaging should adhere to three basic principles, these being justification, optimization and application of dose limits. This article discusses dose reduction techniques and shielding of sensitive organs, particularly the thyroid, during procedures such as intraoral imaging, orthopantomograms and imaging of the pregnant patient.     

The ontogeny of terminal deoxynucleotidyl transferase positive cells in the human fetus

The ontogeny of cells containing the enzyme terminal deoxynucleotidyl transferase (TdT) in human fetal liver, bone marrow, and thymus has been studied using a highly specific antiserum to TdT together with monoclonal antiprecursor cell antibodies in double and triple marker immunofluorescence. TdT+ cells were first observed in fetal liver at 12 wk of gestation and accounted for 55% of the lymphoid-like cells isolated after Ficoll-Hypaque separation. TdT+ cells were first observed in the bone marrow 16 wk after gestation. Like TdT+ cells in normal infant bone marrow, the majority of TdT+ cells in fetal liver and bone marrow expressed both BA-1 and RFB-1 antigens. This suggests that fetal TdT+ cells include progenitors of the B lineage (BA-1+) and perhaps of thymocytes (RFB-1+). Nevertheless, TdT was not observed in fetal thymocytes until after 20 wk of gestation, although thymic blasts and the majority of thymocytes were strongly RFB-1+ from 12 wk of gestation. These results clearly show that fetal thymus is first populated by TdT, RFB-1+, BA-1 cells, but does not exclude the fact that a second "wave" of TdT+ prothymocytes, possibly bone marrow derived, also exists.     

Granulocyte colony-stimulating factor after allogeneic bone marrow transplantation

Hematopoietic growth factors have been shown to be effective in reducing the period of neutropenia after autologous bone marrow transplantation (BMT). Initial concerns over potential aggravation of graft-versus-host disease (GVHD) and increase in the incidence of relapse in patients with myeloid leukemias influenced the number of studies using hematopoietic growth factors after allogeneic BMT. We report the experience with 50 patients treated at a single institution using granulocyte colony-stimulating factor (G-CSF) after allogeneic sibling (n = 30) and matched unrelated (n = 20) BMT. The time to an absolute neutrophil count > or = 500/microL was significantly faster in patients who received G-CSF and cyclosporine and prednisone for GVHD prophylaxis when compared with historical control patients receiving the same GVHD prophylaxis (10 v 13 days, P < .01). A similar accelerated myeloid engraftment was observed for those patients who received the addition of methotrexate for GVHD prophylaxis when compared with historical control patients receiving the same GVHD prophylaxis regimen (16 v 19 days, P < .05). The median time to engraftment for patients receiving a matched unrelated BMT and G-CSF was 17 days (range 13 to 26). We did not observe any increase in GVHD or early mortality in the matched related sibling BMT. The incidence of acute GVHD in the matched unrelated BMT recipients was also low at 21%; however, 9 patients (45%) died within 100 days of the date of BMT, similar to the experience reported with granulocyte-macrophage CSF. This study confirms the efficacy of G-CSF in accelerating myeloid engraftment after allogeneic matched sibling BMT. The higher early mortality associated with patients receiving matched unrelated BMT suggests that randomized controlled trials using G-CSF after allogeneic BMT should be performed.     

A multiparameter analysis of sickle erythrocytes in patients undergoing hydroxyurea therapy

During 24 weeks of hydroxyurea treatment, we monitored red blood cell (RBC) parameters in three patients with sickle cell disease, including F-cell and F-reticulocyte profiles, distributions of delay times for intracellular polymerization, sickle erythrocyte adherence to human umbilical vein endothelial cells in a laminar flow chamber, RBC phthalate density profiles, mean corpuscular hemoglobin concentration and cation content, reticulocyte mean corpuscular hemoglobin concentration, 1H-nuclear magnetic resonance transverse relaxation rates of packed RBCs, and plasma membrane lateral and rotational mobilities of band 3 and glycophorins. Hydroxyurea increases the fraction of cells with sufficiently long delay times to escape the microcirculation before polymerization begins. Furthermore, high pretreatment adherence to human umbilical vein endothelial cells of sickle RBCs decreased to normal after only 2 weeks of hydroxyurea treatment, preceding the increase in fetal hemoglobin levels. The lower adhesion of sickle RBCs to endothelium would facilitate escape from the microcirculation before polymerization begins. Hydroxyurea shifted several biochemical and biophysical parameters of sickle erythrocytes toward values observed with hemoglobin SC disease, suggesting that hydroxyurea moderates sickle cell disease toward the milder, but still clinically significant, hemoglobin SC disease. The 50% reduction in sickle crises documented in the Multicenter Study of Hydroxyurea in Sickle Cell Disease is consistent with this degree of erythrocyte improvement.     

A gene for hereditary pancreatitis maps to chromosome 7q35

BACKGROUND & AIMS: Hereditary pancreatitis (HP) is an autosomal- dominant disorder with incomplete penetrance characterized by recurrent bouts of severe epigastric pain with onset usually at 5-10 years of age. A genetic linkage study was designed to identify the HP gene. METHODS: A 500-member pedigree was constructed from a U.S. kindred centered in eastern Kentucky and western Virginia. A genome-wide search strategy was employed using a 36-member subset of this family to determine the genetic locus for HP. Testing for linkage to microsatellite loci was performed at 20-cM intervals. RESULTS: Linkage was established between the HP phenotype and chromosome 7q in this subset of the family. Modeled as an autosomal dominant disorder with 80% penetrance, a maximal multipoint logarithm of the odds score of 4.3 was obtained using a four-point analysis consisting of markers D7S684, D7S661, D7S505, and the HP locus. Two microsatellite markers, D7S661 and D7S505, that correspond to the 7q35 region of chromosome 7 spanning a 6-cM region did not evidence obligate recombinations with HP. The centromeric and telomeric limits are defined by recombinations at D7S684 and D7S483, respectively, which generates a 19-cM locus for HP. Utilizing family members from the extended pedigree, a break in the high-risk haplotype between D7S684 and D7S661 was observed, which suggests it may be possible to exclude an additional 8 cM from the HP locus. A maximal pairwise logarithm of the odds score of 4.73 at a recombination fraction of theta at D7S684 was obtained with the addition of these extended family members. CONCLUSIONS: Linkage of HP to 7q35 represents a major advancement in our understanding of the genetic basis of this disorder. (Gastroenterology 1996 Jun;110(6):1975-80)