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Vienna, Austria

Lawo J.-P.,Baxter Innovations GmbH | Lawo N.C.,University of Natural Resources and Life Sciences, Vienna
Journal of Applied Entomology | Year: 2011

The intrinsic rate of natural increase (r m) is a common measurement in entomology to describe and evaluate the growth and adaptation of a population of arthropods to certain environmental conditions. Following the method of Birch, the r m is the solution of an exponential equation, which depends on the whole life cycle of each female and her survival time. A simplification of this equation was provided by Wyatt and White, which allows the study to be shortened as it does not depend on any survival times and only a part of the life cycle of the females. Therefore, this method has become quite popular among entomologists. As the r m is a population parameter, it lacks any variance and thus a valid statistical comparison of r ms for different populations is not straightforward. Hence, many approaches include statistical misconceptions. We discuss those approaches, apply them to real data and demonstrate some drawbacks of them. Furthermore, we present an easy to implement and consistent method for the comparison of r ms. © 2011 Blackwell Verlag, GmbH. Source

Jaki T.,Lancaster University | Wolfsegger M.J.,Baxter Innovations GmbH
Statistics in Medicine | Year: 2012

Pharmacokinetic (PK) studies aim to understand the kinetics of absorption, distribution, metabolism and elimination of a drug. Typically, such studies involve measuring the concentration of the drug in the plasma or blood at several time points after drug administration. In studying the PK behaviour, either the non-compartmental approach or alternatively a modelling approach can be utilized. Traditionally, the non-compartmental approach makes minimal assumptions about the data-generating process but requires the data to be collected in a very structured way. Conversely, the modelling approach depends heavily on assumptions about the data-generating process but does not impose a specific data structure. In this paper, we will discuss non-compartmental methods for estimating the area under the concentration versus time curve and other common PK parameters that use minimal assumptions about the data structure making it applicable to a wide range of PK studies. We will evaluate the methods using simulation and give an illustrative example. © 2011 John Wiley & Sons, Ltd. Source

Jaki T.,Lancaster University | Wolfsegger M.J.,Baxter Innovations GmbH
Pharmaceutical Statistics | Year: 2011

The study of the pharmacokinetic (PK) behavior of a compound is crucial to understand the absorbtion, distribution, metabolism and elimination of a drug by the body. PK studies involve measuring the concentration of the drug in the plasma or blood at several time points post drug administration. The classic complete data design samples each subject at all predefined time points. Ethical considerations and restrictions in blood volume, however, lead to incomplete data designs being frequently used instead. In serial sampling designs only one sample is taken from each subject, whereas batch designs take samples more than once from each subject, but not at all time points. In this manuscript the R package PK, which enables the computation of various PK parameters in complete and incomplete data designs, is introduced and some examples are given. Copyright © 2010 John Wiley & Sons, Ltd. Source

Birschmann I.,Hannover Medical School | Dittrich M.,University of Wurzburg | Eller T.,Institute For Laboratoriumsmedizin | Wiegmann B.,Hannover Medical School | And 3 more authors.
Journal of Heart and Lung Transplantation | Year: 2014

Background Thromboembolic and bleeding events in patients with a left ventricular assist device (LVAD) are still a major cause of complications. Therefore, the balance between anti-coagulant and pro-coagulant factors needs to be tightly controlled. The principle hypothesis of this study is that different pump designs may have an effect on hemolysis and activation of the coagulation system. Referring to this, the HeartMate II (HMII; Thoratec Corp, Pleasanton, CA) and the HeartWare HVAD (HeartWare International Inc, Framingham, MA) were investigated. Methods For 20 patients with LVAD support (n = 10 each), plasma coagulation, full blood count, and clinical chemistry parameters were measured. Platelet function was monitored using platelet aggregometry, platelet function analyzer-100 system (Siemens, Marburg, Germany), vasodilator-stimulated phosphoprotein phosphorylation assay, immature platelet fraction, platelet-derived microparticles, and von Willebrand diagnostic. Results Acquired von Willebrand syndrome could be detected in all patients. Signs of hemolysis, as measured by lactate dehydrogenase levels (mean, 470 U/liter HMII, 250 U/liter HVAD; p < 0.001), were more pronounced in the HMII patients. In contrast, D-dimer analysis indicated a significantly higher activation of the coagulation system in HVAD patients (mean, 0.94 mg/liter HMII, 2.01 mg/liter HVAD; p < 0.01). The efficacy of anti-platelet therapy using clopidogrel was not sufficient in more than 50% of the patients. Conclusions Our results support the finding that all patients with rotary blood pumps suffered from von Willebrand syndrome. In addition, a distinct footprint of effects on hemolysis and the coagulation system can be attributed to different devices. As a consequence, the individual status of the coagulation system needs to be controlled in long-term patients. © 2014 International Society for Heart and Lung Transplantation. Source

Baxter Innovations GmbH | Date: 2011-08-04

A medium is described for the protein-free and serum-free cultivation of cells, especially mammalian cells, whereby the medium contains a proportion of soy hydrolysate.

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