Search bioRxiv⌕ Search

Biology subjects

Ibrahim, M. A.

Publications and source records attributed to Ibrahim, M. A..

2 recordsLinked to original sources

Performing Roux-N Y Gastric Bypass on Rabbits: Perspective Report to Evaluate Body Weight Changes Food Consumption, And the Malabsorption of Vitamin D3

In 1998, Dr. Scopinaro published the first-ever known bariatric surgery, followed by reports by Buchwald and Oien in 2003 and 2013 [1,2]. Bariatric surgery (BS) is the most effective therapy against obesity, and recently it was recommended for type 2 diabetes as a therapeutic plan [3]. BS includes; Roux-en-Y gastric bypass (RYGB), sleeve gastrectomy, and laparoscopic adjustable gastric banding has gained the attention of most healthcare providers in elevation of the issue of obesity for its ease and fast results, especially with patients with mobility problems and those with high risk to develop chronic diseases [1,2]. Gastric bypass is considered the most common BS and a gold standard for weight loss, also known as Roux-en-Y gastric bypass (RYGB). The procedure of this BS is by creating a small pouch of the stomach (300 mL capacity) connected directly to the jejunum by bypassing the duodenum. RYGB has many advantages, such as; the alteration of guts hormones, which reduces appetite and hunger feeling, increases energy expenditure, causes significant long-term weight loss (60-80% of the excess body weight), decreases the amount of food consumed, and preserves 50% of the weight loss during this procedure. However, RYGB has some disadvantages. The most critical issue regarding this BS is altering the absorption of many medicines and nutrients, such as; vitamin D3 (Vit D3) [4,5]. (American Society for Metabolic and Bariatric Surgery. Bariatric Surgery Procedures. https://asmbs.org/patients/bariatric-surgery-procedures (accessed Feb 15, 2020). RYGB was performed on rodents before [6] but was never applied to rabbits. To determine the malabsorption procedure after the RYGB, the pharmacokinetics of the substance must be attained, and data must be calculated, such as; Cmax and Tmax, to determine the absorption mutation. It was reported that pharmacokinetic studies on rodents could not be accurate due to the erratic absorption of the rodents [7]; thus, many studies have suggested using larger animals, such as rabbits, that do not address the same problem [8]. The current study investigates the ability to perform RYGB on rabbits and tests the effect of the surgery on body weight, food consumption, and the absorption of Vit D3.

pharmacology and toxicology↗

Assessing biological network dynamics: Comparing numerical simulations with analytical decomposition of parameter space

Mathematical modeling of the emergent dynamics of gene regulatory networks (GRN) faces a double challenge of (a) dependence of model dynamics on parameters, and (b) lack of reliable experimentally determined parameters. In this paper we compare two complementary approaches for describing GRN dynamics across unknown parameters: (1) parameter sampling and resulting ensemble statistics used by RACIPE (RAndom CIrcuit PErturbation), and (2) use of rigorous analysis of combinatorial approximation of the ODE models by DSGRN (Dynamic Signatures Generated by Regulatory Networks). We find a very good agreement between RACIPE simulation and DSGRN predictions for four different 2- and 3-node networks typically observed in cellular decision making. This observation is remarkable since the DSGRN approach assumes that the Hill coefficients of the models are very high while RACIPE assumes the values in the range 1-6. Thus DSGRN parameter domains, explicitly defined by inequalities between systems parameters, are highly predictive of ODE model dynamics within a biologically reasonable range of parameters.

systems biology↗