Papers by Katerina Prohaska
The Analyst
Reproducible in situ SERS delivers a significantly reduced analysis time compared to HPLC, allowi... more Reproducible in situ SERS delivers a significantly reduced analysis time compared to HPLC, allowing timely decisions regarding Synechocystis PHB production.
Blood
TFPI is a Kunitz-type protease inhibitor which efficiently regulates the extrinsic coagulation pa... more TFPI is a Kunitz-type protease inhibitor which efficiently regulates the extrinsic coagulation pathway. It is composed of three flexible linked Kunitz-type domains (KD) where KD1 and KD2 are involved in efficient inhibition of TF/FVIIa and FXa. TFPI inhibition has been shown to improve coagulation and hemostasis in hemophilia models in vitro and in vivo. Recombinant KD1-KD2 (residues 22-150) produced by E. coli and complexed to JBT-B5, a cyclic peptide composed of 23 amino acids, was co-crystallized in 20% w/v PEG6000 and 50mM imidazole, pH8.0. JBT-B5 binding to TFPI was verified by BiaCore experiments with TFPI immobilized on a chip surface. Functional inhibition of TFPI by JBT-B5 was tested in model assays including TFPI inhibition of FXa, FX activation by TF/FVIIa, inhibition of TFPI released upon platelet activation, and by global hemostatic assays including calibrated automated thrombography in FVIII-inhibited plasma and rotational thomboelastometry (ROTEM) using FVIII-inhibite...
Blood
2245 Blood coagulation is initiated by the tissue factor-factor VIIa (TF-FVIIa) complex which cle... more 2245 Blood coagulation is initiated by the tissue factor-factor VIIa (TF-FVIIa) complex which cleaves and activates coagulation factor X to Xa (FXa). Tissue factor pathway inhibitor (TFPI) controls this key process and thus plays a crucial role in maintaining the delicate balance of pro- and anticoagulant processes. Inhibition of TFPI in hemophilia plasma and in a rabbit model of hemophilia has been shown to improve coagulation and hemostasis (Nordfang et al., Thromb Haemost. 1991;66:464; Erhardsen et al., Blood Coagulation and Fibrinolysis 1995;6:388). TFPI is a Kunitz-type protease inhibitor that inhibits FXa and TF-FVIIa. TFPI is a slow, tight-binding FXa inhibitor which rapidly forms a loose FXa-TFPI complex that slowly isomerises to a tight FXa-TFPI* complex. The FXa-TFPI* complex inhibits TF-FVIIa by formation of a quaternary FXa-TFPI-TF-FVIIa complex. Using a library approach, we selected a peptide which binds and inhibits TFPI. We located the binding site of the antagonistic...
Fresenius' journal of analytical chemistry, 2000
An electrothermal atomic absorption method (ETAAS) for the direct determination of trace elements... more An electrothermal atomic absorption method (ETAAS) for the direct determination of trace elements (Cd, Cr, Cu, Mn, Se) both in blood fractions (erythrocytes, plasma and lymphocytes) and whole blood was developed. Zeeman background correction and graphite tubes with L'vov platforms were used. Samples were diluted with HNO3/Triton X-100 and pipetted directly into the graphite tube. Ashing, pretreatment and atomization steps were optimized carefully for the different fractions and elements applying different matrix modifiers for each element. For the lymphocyte fraction a multi-fold injection technique was applied. Low detection limits of the ETAAS method (Cd 0.13 microgram/L, Cr 0.11 microgram/L, Cu 0.52 microgram/L, Mn 0.13 microgram/L, Se 0.7 microgram/L of whole blood) combined with small quantities of sample necessary for analysis allow determination of trace elements in this matrix. Verification of possible differences in the trace element status of humans was performed with ...
Fresenius' journal of analytical chemistry, 2000
Inductively coupled plasma-optical emission spectrometry (ICP-OES) was applied to the determinati... more Inductively coupled plasma-optical emission spectrometry (ICP-OES) was applied to the determination of the elements Ca, Mg, Fe, Cu, and Zn in blood plasma, erythrocytes, lymphocytes, and whole blood to obtain reliable data on their distribution in blood fractions. The samples were carefully collected to avoid contamination. Two different nebulizers (Babington and Meinhard) were tested and optimized for this analytical problem. Line selections for all elements of interest were performed (LODs were 0.8 microg/L for Ca, 1.7 microg/L for Cu, 3.0 microg/L for Fe, 1.1 microg/L for Mg, and 4.2 microg/L for Zn). Recoveries were determined as approx. 100%, and standard reference material was analyzed to obtain reliable data on element distribution. The optimized method was applied to the determination of Ca, Mg, Fe, Cu, and Zn in the course of a clinical study on blood and blood fractions of two groups of humans of differing health. The concentrations measured in blood fractions were verifie...
Biological Trace Element Research, 2001
Journal of Chromatography A, 2002
Journal of Analytical Atomic Spectrometry, 2000
ABSTRACT ETAAS, FIA-ETAAS and HG-ICP-AES methods were applied for measuring selenium in blood and... more ABSTRACT ETAAS, FIA-ETAAS and HG-ICP-AES methods were applied for measuring selenium in blood and blood fractions. For ETAAS, the temperature program was optimized, namely the ashing, the pretreatment and the atomization steps. For this purpose real blood samples were used as the matrix. Different chemical modifiers were tested. A combination of Pd and Mg(NO3)2 was found to be optimal using a pretreatment temperature of 1100°C, an ashing temperature of 600°C and an atomization temperature of 1900°C. For fractions with low selenium content a multi-fold injection technique was applied. For comparison, measurements by FIA-ETAAS and HG-ICP-AES were performed. They were in good agreement with the results obtained by direct ETAAS measurement. As an application of the method Se was determined in blood and blood fractions (erythrocytes, plasma and lymphocytes) of two groups of people. For the selenium determination in whole blood a detection limit of 0.7 ng ml−1 by ETAAS, of 0.5 ng ml−1 by HG-ICP-AES and of 0.05 ng ml−1 by FIA-ETAAS was obtained.
Journal of Agricultural and Food Chemistry, 1999
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Papers by Katerina Prohaska