Pseudo-nullclines enable the analysis and prediction of signaling model dynamics.

A powerful method to qualitatively analyze a 2D system is the use of nullclines, curves which separate regions of the plane where the sign of the time derivatives is constant, with their intersections corresponding to steady states. As a quick way to sketch the phase portrait of the system, they can be sufficient to understand the qualitative dynamics at play without integrating the differential equations. While it cannot be extended straightforwardly for dimensions higher than 2, sometimes the phase portrait can still be projected onto a 2-dimensional subspace, with some curves becoming pseudo-nullclines.

Adenoviral Transfer of Human Aquaporin-8 Gene to Mouse Liver Improves Ammonia-Derived Ureagenesis.

We previously reported that, in cultured hepatocytes, mitochondrial aquaporin-8 (AQP8) channels facilitate the conversion of ammonia to urea and that the expression of human AQP8 (hAQP8) enhances ammonia-derived ureagenesis. In this study, we evaluated whether hepatic gene transfer of hAQP8 improves detoxification of ammonia to urea in normal mice as well as in mice with impaired hepatocyte ammonia metabolism. A recombinant adenoviral (Ad) vector encoding hAQP8, AdhAQP8, or a control Ad vector was administered via retrograde infusion into the bile duct of the mice.

A nested bistable module within a negative feedback loop ensures different types of oscillations in signaling systems.

In this article, we consider a double phosphorylation cycle, a ubiquitous signaling component, having the ability to display bistability, a behavior strongly related to the existence of positive feedback loops. If this component is connected to other signaling elements, it very likely undergoes some sort of protein-protein interaction. In several cases, these interactions result in a non-explicit negative feedback effect, leading to interlinked positive and negative feedbacks.

Resource utilization and disaggregated cost analysis of bariatric surgery in the Australian public healthcare system.

Objectives: To present a comprehensive real-world micro-costing analysis of bariatric surgery.

Methods: Patients were included if they underwent primary bariatric surgery (gastric banding [GB], gastric bypass [GBP] and sleeve gastrectomy [SG]) between 2013 and 2019. Costs were disaggregated into cost items and average-per-patient costs from the Australian healthcare systems perspective were expressed in constant 2019 Australian dollars for the entire cohort and subgroup analysis.

Healthcare resource utilisation and predictors for critical care unit admissions after primary bariatric surgery in an Australian public hospital setting: an exploratory study using a mixed-methods approach.

Objectives The aim of this exploratory study was to investigate resource use and predictors associated with critical care unit (CCU) admission after primary bariatric surgery within the Tasmanian public healthcare system. Methods Patients undergoing primary bariatric surgery in the Tasmanian Health Service (THS) public hospital system between 7 July 2013 and 30 June 2019 were eligible for inclusion in this study. The THS provides two levels of CCU support, an intensive care unit (ICU) and a high dependency unit (HDU).