Freshly isolated hepatocytes are currently regarded as the most superior in vitro model for use in prediction studies, in particular to provide estimates of in vivo intrinsic clearance (CL(int)). However, due to their loss of viability within 4 h and a decrease in cytochrome P450-dependent metabolism upon culture, newer cellular models are being developed. Cryopreserved hepatocytes have several...

Xanthine Oxidase is of importance because of its potential to generate superoxide anion and hydrogen peroxide; reactive oxygen species that have been implicated in many instances of ischaemia-reperfusion injury [I]. The proposed pathogenic mechanism (21 is largely based on the well known properties of the bovine milk and rat liver enzymes [3] and depends on the ischaemia-induced proteolytic con...

Biosensor behaviour is characterised by non-linear differential equations that describe well-defined physical, chemical, and biological processes. Mathematical modelling of these biosensors highly desirable since they have many applications. These models enable the prediction a variety their properties. In this study, cyclic conversion substrate in an amperometric biosensor with oxidase enzyme ...

Abstract The venerable process of cellular respiration is essential for cells to produce energy from glucose molecules, in order carry out work. responsible producing molecules ATP, a molecule which thermodynamically coupled with other biochemical and biophysical processes provide such occur. While the biology, one cycle occurs only matter milliseconds, so, it would be impractical measure time ...

It is known that the enzyme activities of non-target organisms are influenced in vivo or vitro by pesticides play a major role to obtain higher yields field agriculture. foreseen used for various purposes may negatively affect lipase, an digestive system, non target organisms. Therefore, this study, effect diazinon (organophosphate class) and carbaryl (carbamate pesticides, which be widely agri...

Estuaries emit a large but highly uncertain amount of N2O into the atmosphere. To better understand cycling processes in estuaries, we provide first direct observations consumption seasonally anoxic Chesapeake Bay, largest estuary United States. rates waters reached up to 3.3 nmol L-1 d-1 were generally undetectable oxygenated waters. However, substantially enhanced when oxygen concentration wa...

A novel method of estimating enzyme kinetic parameters is presented using the Lambert omega function coupled with nonlinear regression. Explicit expressions for the substrate and product concentrations in the integrated Michaelis-Menten equation were obtained using the omega function which simplified kinetic parameter estimation as root-solving and numerical integration of the Michaelis-Menten ...

Quasi steady-state enzyme kinetic models are increasingly used in systems modelling. The Michaelis Menten model is popular due to its reduced parameter dimensionality, but its low-enzyme and irreversibility assumption may not always be valid in the in vivo context. Whilst the total quasi-steady state assumption (tQSSA) model eliminates the reactant stationary assumptions, its mathematical compl...

Glucose is the major substrate that sustains normal brain function. When the brain glucose concentration approaches zero, glucose transport across the blood-brain barrier becomes rate limiting for metabolism during, for example, increased metabolic activity and hypoglycemia. Steady-state brain glucose concentrations in alpha-chloralose anesthetized rats were measured noninvasively as a function...

Ruminally undegraded protein (RUP) values of blood meal (n = 2), hydrolyzed feather meal (n = 2), fish meal (n = 2), meat and bone meal, and soybean meal were estimated using an in situ method, an inhibitor in vitro method, and an inhibitor in vitro technique applying Michaelis-Menten saturation kinetics. Degradation rates for in situ and inhibitor in vitro methods were calculated by regression...