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Biomedical subjects

E A Beck

Publications and source records attributed to E A Beck.

At least 73 records · Page 4Linked to original sources
PubMed1979

A modified assay for studies of cultured granulocyte precursors: cryopreservation of stimulating mononuclear cells.

Mononuclear cells (MNC), isolated from peripheral blood of healthy donors, were cryoprotected by dimethyl sulfoxide and stored in liquid nitrogen. Colony-stimulating factor (CSF), produced by cryopreserved MNC, was compared with that of nonfrozen controls in a double-layer agar system with human bone marrow as target cells. Our results indicate that cryopreserved MNC retain their ability to stimulate myelopoiesis-committed stem cells after freezing. In addition, evidence was obtained that CSF of feeder layers changes, depending on the duration of preincubation and cell concentration. In a system where either stimulating or target cells are cryopreserved the dynamics of interactions between normal or abnormal cell lines can thus be studied.

Blood Preservation↗
PubMed1977

Effects of amidination and chemical cross-linking on human factor VIII (antihemophilic factor).

The bifunctional reagent dimethyl suberimidate, reacting with primary amino groups of proteins, was used to cross-link highly purified human factor VIII. Reaction products were reduced with beta-mercaptoethanol or treated with Rhizopus arrhizus triglyceride lipase. The proportions of the dissociated subunits and their oligomers were calculated from the relative staining intensities of individual bands following polyacrylamide electrophoresis in the presence of sodium dodecyl sulfate. Low concentrations of dimethyl suberimidate (up to 0.5 mM) produced covalently linked dimers which retained full functional (coagulant and von Willebrand factor) activities. Treatment with increasing concentrations of dimethyl suberimidate resulted in an almost simultaneous appearance of both trimeric and tetrameric species, suggesting the existence of specific intra-dimer contacts. A parallel decrease of functional activities was observed at higher concentrations of dimethyl suberimidate. A monofunctional reagent (ethyl acetimidate), reacting similarly with primary amino groups, amidinated factor VIII at rates similar to dimethyl suberimidate. Up to 40% amidinated factor VIII retained full biological activities. We conclude that the most reactive lysine residues are not involved in the active sites responsible for either coagulant or von Willebrand activity.

Blood Coagulation↗
PubMed1977

Pharmacokinetics of heparin after a single intravenous or subcutaneous injection.

In 2 groups of 4 probands the pharmacokinetics of heparin were investigated by a physiologic method (factor Xa inhibition) and an isotope method (35S-heparin) following a single intravenous injection of 5000 IU heparin and a single subcutaneous injection of 10000 IU heparin respectively. Following intravenous administration the anticoagulant effect and radioactivity fall exponentially. The half-life is about 50 min and the distribution volume 3000 ml (factor Xa inhibition) and 3800 ml (radioactivity). With subcutaneous injection peak concentrations above 0.2 IR heparin/ml were measured by both methods 2-4 h after administration; 9 h after administration, no further factor Xa inhibition was detectable in 2 probands. In the light of these and previously published results, some practical aspects of the conduct of therapy and prophylaxis of thromboembolism with heparin are discussed.

Antithrombin III↗
PubMed1977

Sideroblast score: A sensitive indicator of iron deficiency and hypoproliferative anemia.

The detection and enumeration of sideroblasts depend critically on the method used for iron staining of bone marrow smears. Several methods proposed for semiquantitative evaluation of bone marrow hemosiderin (iron stores) were compared with respect to their suitability for detection of normal and abnormal sideroblasts. Instead of the customary percentage of sideroblasts, the introduction of a sideroblast score is proposed and its diagnostic relevance was prospectively studied. Low sideroblast scores are associated with iron deficiency and hypoproliferative anemia. A normal sideroblast score, despite the absence of stainable hemosiderin, exclused the diagnosis of severe iron depletion. Elevated sideroblast scores may be correlated either with iron overload and/or sideroblastic (sideroachrestic) anemias.

Anemia, Hypochromic↗
PubMed1977

Significance of Hageman factor (coagulation factor XII) for neutrophil locomotion and chemotaxis.

Neutrophils separated from Hageman factor-deficient blood exhibit normal random and directional locomotion. No defect in cytotaxin formation could be demonstrated in Hageman factor-deficient plasma, nor did kallikrein inhibitor interfere with the chemotactic activity of normal immune complex-activated human plasma. The results suggest that the chemotactic activity which is detectable in unfractionated human plasma is not derived from Hageman factor-dependent pathways.

Antigen-Antibody Complex↗