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The Initial Metabolic Medicine Hospital Consult
Published in Michael M. Rothkopf, Jennifer C. Johnson, Optimizing Metabolic Status for the Hospitalized Patient, 2023
Michael M. Rothkopf, Jennifer C. Johnson
Malnutrition could have also resulted from inadequate gastrointestinal (GI) function and the inability to assimilate nutrients from food. Stomach conditions such as intractable nausea, gastritis, peptic ulcer, gastroparesis, dumping syndrome and gastric outlet obstruction can limit the quantity of food consumed. Intestinal diseases such as inflammatory bowel diseases, amyloidosis, enterocutaneous fistulae and short bowel syndrome may decrease the absorptive area of the mucosa. Pancreatic insufficiency and brush border conditions may alter chemical digestion. Diarrheal illnesses due to infection, bile acids or inflammation may limit transit time and deplete fluids and electrolytes.
The gastrointestinal tract
Published in Simon R. Knowles, Laurie Keefer, Antonina A. Mikocka-Walus, Psychogastroenterology for Adults, 2019
Christopher F.D. Li Wai Suen, Peter De Cruz
In response to the presence of food in the mouth, salivary glands located around the mouth produce saliva, which initiates the chemical digestion of food in the mouth. The largest salivary glands are the parotid glands situated in front of the ear, on either side of the face. Saliva contains mucin (a type of protein responsible for the gel-like consistency of saliva), water, and digestive enzymes. These enzymes start the process of chemical digestion in the mouth. Amylase breaks down starch (a complex form of carbohydrate), and lipase breaks down lipids (fats). Saliva also helps keep teeth healthy and has antimicrobial properties.
Exposure
Published in Frank A. Barile, Barile’s Clinical Toxicology, 2019
The primary function of the stomach is the mechanical and chemical digestion of food. Absorption is secondary. Consequently, several factors influence the transit and stability of a drug in the stomach, thereby influencing gastric emptying time (GET). The presence of food delays absorption and dilutes the contents of the stomach, thus reducing subsequent drug transit. An increase in the relative pH of the stomach causes a negative feedback inhibition of stomach churning and motility, which also results in delayed gastric emptying. Any factor that slows stomach motility will increase the amount of time in the stomach, prolonging the GET. Thus, the longer the GET, the greater the duration of a chemical within the stomach, and the more susceptible it is to gastric enzyme degradation and acid hydrolysis. In addition, prolonged GET delays passage to, and subsequent absorption in, the intestinal tract.
A comparative study on the accumulation of toxic heavy metals in fish of the Oman Sea: effects of fish size, spatial distribution and trophic level
Published in Toxin Reviews, 2023
About 200 g of dorsal muscle was dissected from each fish sample to assay heavy metals content. The samples were then frozen and kept at −20 °C immediately after fishing for further chemical analysis in lab. In lab, the tissue samples (0.5 ± 0.005 g) were weighed and then subjected to chemical digestion according to Vinodhini and Narayanan (2008). For this purpose, the tissue samples were poured into 25 ml digestion flasks and ultrapure concentrated nitric acid (HNO3) and hydrogen peroxide (H2O2) (1:1 v/v) were added. Then, the flasks were heated to 130 °C to dissolve all tissue components. After allowing 1:30 h for cooling, the digested tissue samples were diluted up to mark with double distilled water and filtered through 0.45 µ^m nitrocellulose membrane filter.
Distribution of 210Po in spice plants cultivated by conventional farming
Published in International Journal of Radiation Biology, 2022
A known mass of processed spice and soil sample was taken for wet washing through chemical digestion. Organic matters in known mass of sample were removed by adding 4 N HNO3 and subsequent incremental addition of mixture of concentrated HNO3 and H2O2. 0.5 N HCl was used to convert the residue to an acidic medium. 210Po electrostatically deposited on both sides of a polished silver disk for 8 h under constant stirring condition. To avoid a black coating on the polished silver disc by reducing ferric ions into a ferrous state, a small amount of ascorbic acid was added (Yamamoto et al. 1994; Sivakumar 2014).
Enhancing the multi-attribute method through an automated and high-throughput sample preparation
Published in mAbs, 2021
Pongkwan Sitasuwan, Thomas W. Powers, Tiffany Medwid, Yuting Huang, Bradley Bare, L. Andrew Lee
Given that analysis by MAM is performed at the peptide level, proteins must first be digested into peptides, which can be accomplished using an enzymatic or chemical digestion. Trypsin is widely used for peptide mapping experiments, cleaving C-terminal to lysine and arginine residues.10 While trypsin is a highly specific enzyme, it has several limitations that must be considered. The enzymatic activity is enhanced at alkaline pH conditions and elevated temperatures, resulting in artificial protein modifications, or artifacts, as a result of the sample preparation.11,12 Furthermore, the presence of guanidine hydrochloride (GdnHCl), which is frequently used to denature biotherapeutics prior to enzymatic digestion, results in reduced enzymatic activity.13,14 Thus, many procedures have focused on reducing incubation times and removing GdnHCl via a buffer exchange.12 While many of the sample preparation steps can be automated on standard robotic liquid handling systems, protein buffer exchange step is more challenging to automate.15–17 Buffer exchange with size exclusion columns has not been compatible with automation on a robotic system because these columns often require centrifugation for equilibration, loading and elution of the desalting product. The use of a 96-well dialysis plate containing micro-dialysis cartridges submerged in dialysis buffer to automate this buffer exchange step during MAM sample preparation was recently reported.15 While the study demonstrated the feasibility of completely automating the MAM sample preparation on a single liquid handling system, the buffer exchange step alone took 2 hours to complete, potentially introducing additional method artifacts. Here, we report a tip-based buffer exchange approach using the novel SizeX IMCStip to expedite the buffer exchange. A more rapid, yet complete buffer exchange with the SizeX IMCStip uses standard pipetting, where samples are loaded on top of the size exclusion resin bed and zero-pressure tip pickup with controlled air displacement are exploited to precisely elute and separate large molecules from denaturants within 10 minutes.