Papers by Lieselotte Wagner
Thrombosis Research, 2012
Thrombosis Research, Apr 1, 2012
Comparative Biochemistry and Physiology Part B: Comparative Biochemistry, 1974
Aimtract-1. RNAase from the roe of the scallop, Chlamys opercularis, was purified 192-fold, with ... more Aimtract-1. RNAase from the roe of the scallop, Chlamys opercularis, was purified 192-fold, with an apparent recovery of 97 per cent. The final product was free of DNAase, phosphodiesterase and phosphomonoesterase activities. 2. The enzyme is an acid RNAase, with a pH optimum of 5.2, at I = 0"3. 3. The molecular weight of the enzyme is 38,500. 4. The scallop roe RNAase exhibited no marked specificity towards bonds adjacent to either purine or pyrimidine nucleosides. However, the Km for Poly(A) (2-2/zg/ml) was considerably lower than the K m for Poly (U) (400/zg/ml). Neither Poly (C) nor Poly (G) was hydrolysed by the enzyme.
Blood, 2012
3424 Introduction: Dabigatran etexilate is a new orally direct thrombin inhibitor and rivaroxaban... more 3424 Introduction: Dabigatran etexilate is a new orally direct thrombin inhibitor and rivaroxaban is a new oral direct Factor Xa (FXa) inhibitor. The increasing use of the new oral anticoagulants administered for prevention of VTE in patients after orthopedic surgery creates the need of their measurement in the clinical routine. A modified thrombin time based assay can be used for measurement of thrombin inhibitors like dabigatran and the direct Xa inhibitor rivaroxaban can be measured with a chromogenic anti-Xa assay. The aim of this study was to evaluate the performance of the two assays on coagulation analyzers using lyophilized calibrators and controls. Method: The assay for dabigatran measurement is a clotting assay based on the inhibition of a constant and defined concentration of thrombin. Clotting times measured are directly related to thrombin inhibitor concentrations. Calibration of the assay is performed using the lyophilized calibrators with assigned dabigatran values. L...
International Journal of Biochemistry, 1983
ABSTRACT 1.1. This paper describes a method for concentrating proteins before sodium dodecyl sulp... more ABSTRACT 1.1. This paper describes a method for concentrating proteins before sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE).2.2. The procedure is based on gel electrofocusing and the main modifications are that (i) acrylamide gels were cast into 150 × 2.5 mm glass tubes to a height of 15−18 mm, in the remainder of the tube an argininc solution (20 mM arginine. 10% glycerol, 5% 2-mercaptoethanol, pH 10.5) containing the protein to be concentrated was placed, (ii) the pH in the gels was maintained by a mixture of Ampholine pH range 3.5−5.0 and 9−11.3.3. Bovine serum albumin (protein load 4μg), ribonuclease (10μg) ovalbumin (10μg), chymotrypsinogen A (10μg) and hemoglobin (10μg) were concentrated for 2−8 hours at 100 V and 0−5 C with recoveries of about 83%.4.4. The gels containing the concentrated protein were loaded onto a vertical gel slab and analyzed as a function of molecular weight by SDS-PAGE.
Journal of Biochemical and Biophysical Methods, 1983
We have developed a rapid and sensitive method for detecting ribonuclease (RNAase). The method ma... more We have developed a rapid and sensitive method for detecting ribonuclease (RNAase). The method makes use of a RNA-Pyronine Y complex which has a different absorption spectrum from that of Pyronine Y alone. When the RNA is hydrolyzed by RNAase, the spectrum of the complex changes to that of unbound Pyronine Y. The resultant decrease in absorbance at 572 nm is linear for final RNAase concentrations ranging from 2 to 45 ng/ml. Optimal assay conditions were 11.5 micrograms/ml Pyronine Y, 0.56 mg/ml RNA, 80 mumol/ml Tris-HCl buffer, pH 7.8, and 2-45 ng/ml RNAase. The effect of complex concentration, pH, molarity and temperature upon the rate of the reaction were determined. The assay is applicable to crude cell-free extracts.
Experimental Gerontology, 1982
Experimental Gerontology, 1982
Analytical Biochemistry, 1984
A method for electrophoretic concentration of differently charged proteins is described. A nonlin... more A method for electrophoretic concentration of differently charged proteins is described. A nonlinear pH gradient is generated by imposing a potential gradient on an electrolyte system composed of (+)H3PO4-valine (pI 6.0)-Servalyte (pH 9-11)-triethylamine(-). Proteins contained in the valine solution accumulate at the interphase formed between the valine solution and the Servalyte solution. This interphase acts as a barrier or liquid membrane to all proteins having isoelectric points in the range 6-9. For proteins having isoelectric points in the range 5-7 valine is replaced by histidine (pI 7.64) and the Servalyte by Pharmalyte, pH 2.5-5.0. Ribonuclease, hexokinase, bovine serum albumin, and hemoglobin were concentrated and recovered from the top of the column using a peristaltic pump. The duration of concentration process was 1-4 h, the length of the run depending on the experiment scale (20 or 100 ml protein solution), the amount of protein, and the isoelectric point of the protein. Proteins were concentrated 9- to 48-fold, depending on the initial volume and concentration of the protein. The recoveries ranged from 79.7 +/- 1.1 for hemoglobin to 93.17 +/- 2.84 for ribonuclease.
Analytical Biochemistry, 1983
A simple and rapid technique for simultaneous separation of the acidic and basic isoenzymes of ho... more A simple and rapid technique for simultaneous separation of the acidic and basic isoenzymes of horseradish peroxidase is described. Upon application of a potential gradient on the electrolyte system composed of Pharmalyte (pH 2.5-5.0) histidine (pI 7.64), and Ampholyte (pH 9-11), the acidic and basic isoenzymes with pI 4.0-8.4 of horseradish peroxidase accumulated at the two interphases generated by this arrangement, with a recovery of 75 +/- 5%. Some advantages, such as rapidity, simplicity, low cost, good yields, and others, of this system over existing ones are outlined.
AGE, 1982
The possible changes in rRNA amounts in the spleens of immunized and non-Immunized rats during ag... more The possible changes in rRNA amounts in the spleens of immunized and non-Immunized rats during aging were Investigated. The cytoplasmic RNA was extracted from Intact spleens or spleen cell suspensions and 28So/ 18S o, 28Sy118Sy, 28So/28Sy, 18So/18Sy retios were calct~lated, the most-significant-change (P < 0.01) occurring at the level of 28So/28Sy ratio; I.e., there was a six-fold Increase in the ritlo of 28S rRNA In old rats as compared to young rats suggesting a preferential digestion of 26S subunlt by neutral and alkaline RNAase whose activities were found to decrease in old non-immunized rats. In Immunized rats the situation was different, as there was a considerable decrease (over twenty fold) In rRNA from old animals as compared to young ones, the most significant results being obtained with spleen cell suspensions. As age-related changes In the Immune system begin st the time of sexual maturity, we propose the use of rRNA as a marker of rat senescence.
Blood, 2008
Aims: Aim of the study was to show the suitability of the new coagulation analyzer Ceveron® alpha... more Aims: Aim of the study was to show the suitability of the new coagulation analyzer Ceveron® alpha for determination of thrombin generation (TGA) in routine laboratories for discrimination of normal plasma samples from haemophilic and thrombophilic patient samples, from patients with a Lupus syndrome and patients with bleeding disorders. Methods: TGA was determined by a thrombin generation assay based on monitoring the formation of thrombin by means of a fluorigenic substrate upon activation of the coagulation cascade by tissue factor and phospholipids using 2 reagents with different phospholipid concentrations (RClow and RChigh) on Ceveron® alpha. Thrombin generation is measured with a specially adapted TGA fluorimetric module which is placed over the cuvette rotor. Readout parameters were lag time (tLag), peak thrombin (Peak), time to peak(tPeak), velocity index (VI) and area under the curve (AUC). In case of patients with Lupus Anticoagulants a ratio of peak thrombin values trigge...
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Papers by Lieselotte Wagner