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Biomedical subjects

R A Dracker

Publications and source records attributed to R A Dracker.

9 recordsLinked to original sources
PubMed1994

Collection and 28-day storage of human placental blood.

Placental blood was harvested using a novel collection system into packs containing citrate-phosphate-dextrose-adenine and then stored for 28 d. Before and during storage, sterility, adequacy of anticoagulation, blood chemistry, and red cell viability were assessed weekly. The average volume of blood collected was 65 mL (range 30-110 mL) with a 0.42 hematocrit once diluted in anticoagulant. All blood culture specimens were sterile at collection and during storage. Adequate anticoagulation (activated partial thromboplastin time > 90 s) on the day of collection was achieved in 15 specimens, all less than 65 mL of blood volume. Ten specimens, in blood volumes ranging from 65 to 110 mL, had mean activated partial thromboplastin time values of 65.3 +/- 10.2 s. Activated partial thromboplastin time values for all 25 specimens at 1, 2, 3, and 4 wk storage were > 90 s, presumably because of the decline in labile clotting factors after 24 h of storage. Hematocrit, red cell ATP, and red cell shape were maintained during storage. As expected, red cell 2,3-diphosphoglycerate declined and potassium levels rose significantly but were not different than levels reported for adult cells similarly preserved. Based on our results, it appears that placental blood represents a potential source of autologous transfusion for the sick neonate over the first month of life.

Blood Preservation↗
PubMed1992

Cold agglutinin disease after chicken pox. An uncommon complication of a common disease.

Chicken pox, although common, is rarely associated with autoimmune hemolytic anemia. Reported here is the case of an 8-year-old boy who was found to have cold agglutinin disease and severe anemia several days after he contracted chicken pox. The cold agglutinin appeared to be a polyclonal immunoglobulin M antibody with anti-Pr specificity. To our knowledge, this is the fifth reported case of autoimmune hemolytic anemia and the second reported case of cold agglutinin disease with anti-Pr specificity to be associated with chicken pox.

Anemia, Hemolytic, Autoimmune↗
PubMed1989

Granulocyte-macrophage colony-stimulating factor is an endogenous regulator of cell proliferation in juvenile chronic myelogenous leukemia.

Juvenile chronic myelogenous leukemia (JCML) is a rare myeloproliferative disorder of early childhood that is clinically and cytogenically distinct from the well-recognized adult type of chronic myeloid leukemia. Unlike the adult disease, growth of hematopoietic progenitors from peripheral blood (PB) occurs in the absence of exogenous stimulus even at low cell densities. This so-called "spontaneous" growth can be abrogated by adherent cell depletion and appears to depend on production of endogenous growth factors. We studied seven children with JCML to determine the nature of endogenous stimulators. With isolated PB mononuclear cells (PBMNCs) and a 3H-thymidine (3H-TdR) incorporation assay, JCML cells were shown to incorporate high levels of 3H-TdR when cultured in the absence of stimulus even at low cell densities. When neutralizing antisera prepared against each of the four known colony-stimulating factors (CSFs), GM-CSF, G-CSF, M-CSF, and interleukin-3 (IL-3), as well as antisera against interleukin-1 (alpha and beta) and tumor necrosis factor (TNF) were added to these cultures, only the antisera against recombinant human GM-CSF (rhGM-CSF) consistently resulted in significant inhibition of cell proliferation, achieving up to 72% inhibition of 3H-TdR incorporation in one case. Monoclonal antibodies (MoAbs) against rhGM-CSF resulted in a similar and highly significant degree of inhibition. A marked inhibitory effect of rhGM-CSF antiserum on "spontaneous" growth of PB CFU-GM derived colonies in semisolid medium was also demonstrated in four of five patients studied (87% to 90% inhibition). Production of growth factors by highly enriched JCML monocytes was variable. When initially studied in five of the seven patients, the monocytes from three of the patients revealed increased release of IL-1-like activities; two patients had levels similar to those of controls. One patient with normal levels when initially studied was later shown to have markedly increased amounts of IL-1-like activities in a second preparation of monocyte-conditioned medium (MCM). High levels of GM-CSF were detected in the initial MCM from one patient, but this may have indirectly reflected elevated IL-1-like activities present in the MCM. IL-3 and M-CSF levels were either low or undetectable in the patients studied as compared with MCM prepared with normal adult monocytes. These results clearly implicate GM-CSF as the primary endogenous regulator of JCML cell proliferation in culture and suggest that this malignant myeloproliferative disease may in part result from paracrine stimulation of marrow progenitor cells by growth factors/cytokines secreted by the malignant monocytes.

Bone Marrow↗
PubMedDate not supplied

The development and use of oxygen-carrying blood substitutes.

The major criteria by which any blood substitute product will be evaluated prior to commercial usefulness will include evaluations of its: oxygen transport characteristics purity and physical properties potential for and modality of toxicities efficacy in various clinical settings biologic half life metabolism immunogenicity Although a thorough review of these aspects are laborious, they are necessary prior to the performance of clinical trials. The promise and availability of a clinically useful oxygen-carrying blood substitute has been long in coming, however we fortunately enjoy the continued supply of the safest blood products ever available. Further improvements in our homologous blood system continue, while we strive for the development of a blood substitute. The availability of a safe, multi-use oxygen-transporting product could significantly contribute and improve upon the care of acutely ill patients. Table I reviews the current status of the various categories of blood substitutes. We look forward to the introduction of one or more of these products in the near future.

Biological Transport↗