Institute For Klinische Chemie

Hannover, Germany

Institute For Klinische Chemie

Hannover, Germany
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Nowak-Gottl U.,Institute For Klinische Chemie | Langer F.,Universitatsklinikum Eppendorf | Limperger V.,Institute For Klinische Chemie | Mesters R.,Universitatsklinikum Munster | Trappe R.U.,Ev. Diakonie Krankenhaus
Deutsche Medizinische Wochenschrift | Year: 2014

Oral anticoagulants [Vitamin-K-Antagonists, Dabigatran, Rivaroxaban, Apixaban] or antiplatelet agents [Aspirin, Clopidogrel, Prasugrel, Ticagrelor] are effective in preventing thromboembolic diseases. In case of interventional of surgical procedures patients with indications for chronic anticoagulation [atrial fibrillation, valve prosthesis, venous thromboembolism] or use of antiplatelet agents [cerebrovascular events, cardiovascular events] will require interruption of antithrombotic/antiplatelet therapy with the need of replacement with a short-acting agent. Due to limited data available from randomized studies and meta-analyses the evidence level is low in the majority of recommendations. Therefore for each patient the bleeding and thrombosis risk depending on the individual patient constitution and the planned intervention must be weighted. In patients with an intermediate risk for thrombosis the bleeding risk of the scheduled intervention will influence the bridging recommendation: In patients with a low bleeding risk oral anticoagulation/ antiplatelet therapy can be continued or reduced in intensity. In patients with an intermediate or high bleeding risk along with a low thrombosis risk a temporary interruption of the anticoagulation/antiplatelet therapy is feasible. In patients with a high thrombosis and bleeding risk anticoagulation should be bridged with unfractionated heparin [renal insufficiency] or low molecular weight heparin. In the latter risk situation, inhibition of platelet function can be achieved with short-lasting GPIIb-IIIa inhibitors [Eptifibatide, Tirofiban]. Prior to intervention patients treated with the new oral anticoagulants [Dabigatran; Rivaroxaban; Apixaban] are requested to temporary interrupt the anticoagulation depending on the individual drug half-life and their renal function. Bridging therapy with heparin prior to intervention is not necessary with the new oral anticoagulants. © Georg Thieme Verlag KG. Stuttgart.New York.

Tarasov V.,Max Planck Institute of Biochemistry | Schwaiger R.,Institute For Klinische Chemie | Furtwangler K.,Max Planck Institute of Molecular Plant Physiology | Dyall-Smith M.,Charles Sturt University | Oesterhelt D.,Max Planck Institute of Biochemistry
BMC Molecular Biology | Year: 2011

Background: The halophilic archaeon Halobacterium salinarum expresses bacteriorhodopsin, a retinal-protein that allows photosynthetic growth. Transcription of the bop (bacterioopsin) gene is controlled by two transcription factors, Bat and Brz that induce bop when cells are grown anaerobically and under light.Results: A new gene was identified that is transcribed together with the brz gene that encodes a small basic protein designated as Brb (bacteriorhodopsin-regulating basic protein). The translation activity of the start codon of the brb gene was confirmed by BgaH reporter assays. In vivo site-directed mutagenesis of the brb gene showed that the Brb protein cooperates with Brz in the regulation of bop expression. Using a GFP reporter assay, it was demonstrated that Brb cooperates with both Brz and Bat proteins to activate bop transcription under phototrophic growth conditions.Conclusions: The activation of the bop promoter was shown to be dependent not only on two major factors, Bat and Brz, but is also tuned by the small basic protein, Brb. © 2011 Tarasov et al; licensee BioMed Central Ltd.

Haeckel R.,Katrepeler Landstrasse 45e | Wosniok W.,University of Bremen | Klauke R.,Institute For Klinische Chemie
LaboratoriumsMedizin | Year: 2013

A well-accepted tool for method validation is a method comparison study. Results are usually assessed on a scatter plot of which the fitting line is calculated by several approaches, for example, ordinary (vertical) linear regression (OLR), orthogonal regression (OR), Deming regression (DR), Passing-Bablok method (PBR) or standardized principal component regression (SPCR). DR was applied in its general form (gDR), requiring information of the imprecision of at least two different quantities and as simple DR (sDR) with imprecision information of only one quantity. The equation of the regression line calculated by these concepts varies depending on range of measurement, analytical variation and on imprecision ratio ( s AY / s AX ). There is still a global debate about which statistical concept is the most adequate for validating purposes. Various paired random samples with a size of 100 were simulated in 5000 replicates and evaluated with different regression models. The behavior of the slope and intercept of the regression lines were compared under various conditions. Two extreme ranges of measurement and several variance ratios in the absence and presence of bias were studied. The results clearly demonstrated that DR is the only model which can be applied without any precautions under conditions which usually occur in method comparison studies, and therefore should be preferred in laboratory medicine. Other models require restrictions with regard to range of measurement and/ or imprecision profile. Differences of the concentrations at different positions of the measurement interval calculated with regression coefficients of both DRs did not deviate more than the permissible bias. Therefore, the advantage of using gDR does not justify its greater disadvantages in comparison with sDR. © 2013 Walter de Gruyter GmbH.

Schumann G.,Institute For Klinische Chemie | Canalias F.,Autonomous University of Barcelona | Joergensen P.J.,Kolding Hospital | Kang D.,Kyushu University | And 2 more authors.
Clinical Chemistry and Laboratory Medicine | Year: 2010

The primary reference measurement procedures (PRMPs) for the international standardization of catalytic concentration measurements of α-amylase, alanine aminotransferase, aspartate aminotransferase (AST), creatine kinase (CK), γ-glutamyltransferase and lactate dehydrogenase have been performed in reference laboratories for several years. The IFCC Committee on Reference Systems for Enzymes and two reference laboratories, with official accreditation for the PRMPs, have collected useful information on some of the steps of the reference procedures that require special attention. This document comprises errata corrige for minor mistakes in published PRMPs for AST and CK. Several notes on the PRMPs are emphasized. This includes details that are very important for improved standardization, and general suggestions for reducing measurement uncertainty. © 2010 by Walter de Gruyter Berlin New York.

Neumaier M.,Institute For Klinische Chemie | Neumaier M.,University of Heidelberg
LaboratoriumsMedizin | Year: 2016

Circulating cell-free nucleic acids (cfNA, mostly referred to as cfDNA) are increasingly being recognized as a promising new substrate for clinical laboratory diagnostics. DNA, mRNA and miRNA are less likely to circulate in the peripheral blood in a "free naked" form, but rather as a packaged form and thus are fairly protected from degradation. Together with the fact that both qualities and quantities of cfNA vary in a number of important human disorders, this may create an entirely new universe for laboratory diagnostics. First applications enter the arena of routine diagnostic health care, e.g. the sensitive and highly specific detection of tumor mutations that will allow for a molecular profiling of tumor relapse or therapy failure (the so-called "liquid biopsy"). Still, many open questions require resolution including their cross validation with established and important routine biomarkers in the health care lab. Furthermore, critical preanalytical questions, analytical validity and precision need to be addressed to secure the quality of the material analyzed and meaningful results, respectively. Last but not least, circulating nucleic acids uncover a whole new biology of signals traveling through our bodies under various conditions of health and disease. It will be of great scientific importance to understand their biochemical and pathobiochemical implications. It is significant for both the development and implementation of this new diagnostic field that clinical chemistry can provide the required expertise in all these areas, thus ensuring rapid transition of cfNA into clinical medicine. It will complement the plethora of established diagnostic biomarkers that are provided every day to support clinical decisions for the benefit of the patient. © 2016 Walter de Gruyter GmbH, Berlin/Boston.

Muller B.,Ruhr University Bochum | Muller B.,Institute For Klinische Chemie | Prante C.,Ruhr University Bochum | Knabbe C.,Ruhr University Bochum | And 2 more authors.
Glycoconjugate Journal | Year: 2013

Recently, we demonstrated that the human xylosyltransferase II (XT-II) has enzymatic activity and is able to catalyze the initial and rate-limiting step in the biosynthesis of glycosaminoglycans (GAGs) like chondroitin and dermatan sulfate, as well as heparan sulfate and heparin. Therefore, this enzyme also very likely assumes a crucial regulatory role in the biosynthesis of proteoglycans (PGs). In this study, we identified and characterized for the first time the XYLT2 gene promoter region and transcription factors involved in its regulation. Several binding sites for members of the Sp1 family of transcription factors were identified as being necessary for transcriptional regulation of the XYLT2 gene. This was determined by mithramycin A treatment, electrophoretic mobility shift and supershift assays, as well as numerous site-directed mutagenesis experiments. Different 5′ and 3′ deletion constructs of the predicted GC rich promoter region, which lacks a canonical TATA and CAAT box, revealed that a 177 nts proximal promoter element is sufficient and indispensable to drive the constitutive transcription in full strength in HepG2 hepatoma cells. In addition, we also detected the transcriptional start site using 5′-RACE (rapid amplification of cDNA ends). Our results provide an insight into transcriptional regulation of the XYLT2 gene and may contribute to understanding the manifold GAG-involving processes in health and disease. © 2012 Springer Science+Business Media, LLC.

Lichtinghagen R.,Institute For Klinische Chemie | Senkpiel-Jorns D.,Institute For Klinische Chemie | Brand K.,Institute For Klinische Chemie | Janzen N.,Institute For Klinische Chemie
LaboratoriumsMedizin | Year: 2013

Background: The influence of venous congestion on the laboratory values has been demonstrated. The mean percentage deviations seem physiologically questionable because the results depend mainly on the absolute values at the time point t 0 . For a better assessment of the influence of venous congestion time, the biological variability should be taken into account. Methods: The routine laboratory tests were determined in 92 volunteers after up to 6 min of venous congestion. All the values were normalised against the local reference intervals by the z-transformation. Results: All the measured variables except creatinine and sodium showed statistically significant changes under venous congestion, irrespective of whether the changes were expressed as the percentages or z-values. The proteins and protein-associated substances like calcium increased, whereas the soluble small molecules like potassium and glucose decreased. The largest increase was seen for bilirubin ( + 9 % ), while the increase in calcium was low. After normalisation, however, the magnitude and the ranking of the congestion-dependent differences changed markedly. The highest increase could be shown for the total protein ( + 1.4 standard deviations), while bilirubin only revealed a slight increase. As expected, the changes for calcium became much more pronounced, corresponding with those of albumin. Conclusions: The normalised deviations meet the physiological expectations far better. © 2013 Walter de Gruyter GmbH.

Seifert-Klauss V.,TU Munich | Fillenberg S.,TU Munich | Schneider H.,Institute For Klinische Chemie | Luppa P.,Institute For Klinische Chemie | And 2 more authors.
Climacteric | Year: 2012

Introduction Few longitudinal data about rates of bone loss in women in midlife exist. Fewer still with their reproductive states having been carefully assessed and sequentially followed-up. Methods Complete data from 50 women younger than 60 years (mean age at baseline 48.3±5.4 years) were prospectively collected over 9 years. This was done by standardized interviews, measurement of endocrinological parameters as well as bone markers and repeated bone mineral density (BMD) measurements using quantitative computer tomography (QCT). Women were classified in three groups according to their reproductive characteristics over 9 years. Results Significant BMD loss was found in women going through the menopausal transition. In perimenopause, there was a correlation (multiple regression results, r -0.396 and r -0.527) between accelerated bone density loss and increased gonadotropin levels (follicle stimulating hormone, luteinizing hormone). Although significantly higher levels of bone markers (osteocalcin, bone-specific alkaline phosphatase, c-terminal telopeptide cross-linked collagen type I) were measured in postmenopause, the greatest increase in these markers was seen during the menopausal transition. No individual marker's increase, however, was predictive for perimenopausal bone density loss. The major risk factors for rapid bone loss were a lower initial body weight (<57 kg), a body mass index <20 kg/m2 as well as a positive family history of fragility fractures. Conclusions Women in the menopausal transition lose trabecular bone at a rapid rate despite intermittently high and usually normal estrogen levels. This is the only prospective study to date that documents trabecular bone changes in women through the entire perimenopause, which may last up to 10 years. © 2012 International Menopause Society.

PubMed | Institute For Klinische Chemie
Type: Journal Article | Journal: Journal of clinical oncology : official journal of the American Society of Clinical Oncology | Year: 2016

8067 Background: Accumulation of MTX in patients (pts.) with renal failure after HD-MTX is a rare, but life-threatening complication. Recombinant CPG2 cleaves MTX into the less toxic metabolite 2,4-diamino-N-pteroic acid (DAMPA) and glutamate. We have conducted an emergency use protocol using CPG2 in pts. with delayed MTX-elimination/renal failure after HD-MTX.Pts. with MTX serum levels of >5mol/l at 42h, >1mol/l at 42h* or >0.4mol/l at 48h* (* + renal insufficiency: creatinine >1.5 upper limit of normal) after start of HD-MTX (>1g/m2 MTX) were eligible. Pts. with renal insufficiency were also eligible at <42h. Concentrations of MTX and metabolites were measured by high-performance-liquid-chromatography (HPLC) in acidified serum samples.42 pts. (age: 10-78 years) with lymphoma (29), acute lymphoblastic leukemia (12) or germ cell tumor (1) were enroled. MTX serum levels at registration ranged from 1.01 - 1187.42mol/l (median: 9.8). CPG2 was given at dosages ranging from 10-58units/kg i.v. at median 55h (range: 27-176h) after start of HD-MTX. Except for skin reaction grade III and fever grade II in one pt. each, CPG2 was well tolerated. Serial serum samples were available for HPLC analysis in 24 pts.. MTX serum levels rapidly declined from a median of 5.11mol/l (range: 0.35-165.86) to 1mol/l or less within 7-50 minutes after CPG2 administration. Serum creatinine levels remained normal in 2 pts. and returned to normal values in 21 pts. after a median of 17 days (range: 4-127). The remaining 19 pts. had median peak serum creatinine levels of 283mol/l which subsequently declined to a median of 150mol/l by days 1-58 after CPG2.CPG2 is a safe and effective antidote in HD-MTX treated pts. with delayed MTX-clearance/renal failure. Further studies are needed to evaluate the efficacy of CPG2 with respect to clinical endpoints, as well as the role of this novel drug as a standard rescue agent. [Table: see text].

Luppa P.B.,Institute For Klinische Chemie
Methods in molecular biology (Clifton, N.J.) | Year: 2010

Surface plasmon resonance (SPR) is a novel biophysical detection method. In combination with sophisticated surface chemistries and sensing instrumentations, SPR biosensors are approved as tools for molecular interaction studies. SPR plays also a role in interaction proteomics. Once being detected in urine, SPR helps to unravel the functions of new proteins. Due to its outstanding analytical characteristics, SPR also moves more and more into the realm of quantitative analyses in the clinical laboratory. Complex urine determinations of proteins and/or metabolites will bring the SPR biosensor both to the core lab and to point-of-care-testing.This review delineates first the optical phenomena of SPR near to the gold surface, and also the main features of bioconjugation chemistry on a solid-state surface. Then the kinetic calculation of molecular interaction analysis using SPR is introduced. In order to portray the capability of the method, new applications in urine proteomics and proteinuria diagnostics are finally described in detail.

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