Muttenz, Switzerland
Muttenz, Switzerland

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Sciotti M.A.,Hochschule fur Life science | Hasan L.,Buhlmann Laboratories AG | Scholer A.,Labormedizin Universitatsspital Basel | Jermann T.M.,Buhlmann Laboratories AG | And 2 more authors.
Chimia | Year: 2010

Gamma hydroxybutyric acid (GHB) is a regulated therapeutic drug, which naturally occurs in mammalian brain tissues as an intermediate of the GABA (gamma aminobutyric acid) neurotransmitter metabolism. The increasing misuse of GHB as a narcotic or abusing drug in recent years calls for the development of a simple and rapid screening method as an alternative to the currently available, technically demanding diagnostic methods. We have developed a rapid enzymatic assay based on the GHB dehydrogenase of Ralstonia eutropha. The enzyme is expressed as a recombinant protein in Escherichia coli and characterized in terms of reaction mechanism and kinetic parameters for the catalysis of conversion of GHB into succinic semialdehyde (SSA). The concomitant NADH production enables spectrophotometric monitoring of the reaction and the quantification of GHB in physiological fluids depending on initial velocities. We have tested a panel of twelve serum and urine samples containing GHB concentrations from 0.0 to 2.1 mmol/L. GHB dehydrogenase activity obeys a non classical bi bi ping pong mechanism exhibiting substrate inhibition by NAD +. With an optimal NAD+ concentration of 3.7 mmol/L in the reaction, the enzyme yields a KM of 1.0 mmol/L for GHB and a V max of 3.37 mmol/min/mg. The assay shows a linear standard curve from 0.1 to at least 1 mmol/L of GHB. Spiking experiments result in mean recoveries of 92% for urine and 114% for serum, respectively. The comparison to an ion chromatographic reference method exhibits a mean difference of 10% divergence from the target values in urine and 9% in serum, respectively. © Schweizerische Chemische Gesellschaft.


Schwarz-Wings D.,Museum fur Naturkunde Berlin | Meyer C.A.,Naturhistorisches Museum Basel | Frey E.,Staatliches Museum Fur | Manz-Steiner H.-R.,Esslingen University of Applied Sciences | Schumacher R.,Hochschule fur Life science
Proceedings of the Royal Society B: Biological Sciences | Year: 2010

The pre-sacral vertebrae of most sauropod dinosaurs were surrounded by interconnected, air-filled diverticula, penetrating into the bones and creating an intricate internal cavity system within the vertebrae. Computational finite-element models of two sauropod cervical vertebrae now demonstrate the mechanical reason for vertebral pneumaticity. The analyses show that the structure of the cervical vertebrae leads to an even distribution of all occurring stress fields along the vertebrae, concentrated mainly on their external surface and the vertebral laminae. The regions between vertebral laminae and the interior part of the vertebral body including thin bony struts and septa are mostly unloaded and pneumatic structures are positioned in these regions of minimal stress. The morphology of sauropod cervical vertebrae was influenced by strongly segmented axial neck muscles, which require only small attachment areas on each vertebra, and pneumatic epithelia that are able to resorb bone that is not mechanically loaded. The interaction of these soft tissues with the bony tissue of the vertebrae produced lightweight, air-filled vertebrae in which most stresses were borne by the external cortical bone. Cervical pneumaticity was therefore an important prerequisite for neck enlargement in sauropods. Thus, we expect that vertebral pneumaticity in other parts of the body to have a similar role in enabling gigantism. © 2009 The Royal Society.


Case description of the complex course following a mountain bike accident with grade II open fracture of the forearm. Initial treatment was performed with external fixation. Complications after definitive osteosynthesis with plates led to an implant-related infected nonunion. To restore the defect, a y-shaped vascularized fibular graft was used with reconstruction of the stenosed radial artery. © 2015, Springer-Verlag Berlin Heidelberg.


Sciotti M.A.,Hochschule fur Life science | Chen G.J.,NCL New Concept Laboratory | Gygax D.,Hochschule fur Life science
Chimia | Year: 2010

A spectrophotometric assay based on a miniaturized 96-well plate device (IMAPlate) enables a rapid and simple screening of bioengineered recombinant lipases expressed and secreted by Saccharomyces cerevisiae. Starting from a colony, the test delivers a quantitative estimation of enzymatic activity titer in 24 h or less with manual high throughput performances. © Schweizerische Chemische Gesellschaft.


A spectrophotometric assay based on a miniaturized 96-well plate device (IMAPlate) enables a rapid and simple screening of bioengineered recombinant lipases expressed and secreted by Saccharomyces cerevisiae. Starting from a colony, the test delivers a quantitative estimation of enzymatic activity titer in 24 h or less with manual high throughput performances.

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