Biomedical subjects
Publications and source records attributed to T Dengler.
A simple microtiterplate method to screen blood-donors for elevated alanine transaminase (ALT) was developed. The method permits a sufficiently precise measuring at room temperature without temperature control and has a high performance. The method was validated by comparison with a standardized method.
To produce a tri(n-butyl)phosphate/sodium-cholate-treated intermediate-purity factor VIII (FVIII) concentrate with a specific activity of about 1 IU/mg, we used a simple gel filtration step with Sephadex G25 to remove the solvent/detergent reagents from the final product. By exchanging the Sephadex G25 gel for a new high-resolution gel (Sephacryl S400 HR), we obtained a high-purity FVIII concentrate, by simultaneous elimination of about 98% of the extraneous proteins and removal of the solvent/detergent reagents, without reducing the FVIII:c yield and without altering the production scheme. With different protein analysis techniques we analysed the resulting FVIII concentrate and, comparing it to the formerly produced intermediate-purity FVIII concentrate, demonstrated improved purity.
A relatively simple and fast method for the quantitative determination of residual sodium-cholate in tri(n-butyl)phosphate/sodium-cholate treated factor VIII concentrate preparations was developed by solid-phase extraction and reversed-phase high-performance liquid chromatography.
The polymer/aggregate fractions of three human serum albumin preparations (HSA) from different manufacturers were isolated by size-exclusion high-performance liquid chromatography (HPLC) and analyzed by different electrophoretic and immunochemical methods. All of these polymer/aggregate fractions contained only 30-50% albumin. The rest seemed to be mainly heat-denatured haptoglobin which did not react with an anti-haptoglobin serum, whereas the albumin part reacted with an anti-albumin serum. It could be shown that these polymers or aggregates are formed by disulfide bonds between albumin and the small amounts of denatured impurity globulins (haptoglobin, transferrin) during the pasteurization step. The higher the amount of these heat labile globulins in the final preparation before the pasteurization step, the higher was the polymer/aggregate content of the pasteurized albumin preparation.
Formation of particles in human albumin solutions during the 10 h pasteurisation is discussed in detail as well as the formation of albumin polymers during the course of manufacture. The problems of green colour and of aluminium ions occurring in albumin solutions are touched upon.
The K3-antigenic capsular polysaccharide (K3 antigen) of Escherichia coli contains L-rhamnose, a 4-deoxy-2-hexulosonic acid, and an O-acetyl group in the molar ratio of 3:1:1. The backbone consists of a ----2)-O-alpha-L-rhamnopyranosyl-(1----3)-O-alpha-L-rhamnopyranosyl-(1----3)-O-alpha-L-rhamnopyranosyl-(1---- repeating unit. Either one of the 3-linked L-rhamnopyranosyl residues of each repeating unit may be substituted at O-2 with a 4-deoxy-2-hexulosonic acid, an isomer of the furanosyl form of KDO, about 90% of which is acetylated at 0-6. The 4-deoxy-2-hexulosonic acid residue is linked to the L-rhamnan backbone in a very labile linkage which is split by 1% acetic acid (30 min, 100 degrees). The K3 polysaccharide has a molecular weight of approximately 38,000, corresponding to approximately 60 repeating units.
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The structure of the K40 antigenic capsular polysaccharide (K40 antigen) of E. coli O8:K40:H9 was elucidated by determination of the composition, 1H- and 13C-n.m.r. spectroscopy, periodate oxidation and Smith degradation, and methylation analysis. The K40 polysaccharide consists of [(O-beta-D-glucopyranosyluronic acid)-(1----4)-O-(2-acetamido-2-deoxy-alpha-D-glucopyranosyl)-(1----6)-O -(2-acetamido-2-deoxy-alpha-D-glucopyranosyl)-(1----4)] repeating units. All of the glucuronic acid residues are substituted amidically with L-serine.
The structure of the K95 antigenic capsular polysaccharide (K95 antigen) of Escherichia coli O75:K95:H5 was elucidated by determination of the composition, 1H- and 13C-n.m.r. spectroscopy, periodate oxidation, and methylation analysis. The K95 polysaccharide, which contains furanosidic 3-deoxy-D-manno-2-octulosonic acid (KDOf) residues, consists of----3)-beta-D-Rib-(1----8)-KDOf-(2----repeating units, has a molecular weight of approximately 25,000 (approximately 65 repeating units), and is randomly O-acetylated (1 acetyl group per repeating unit at unknown positions).