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Parenteral Nutrition Components, Admixture and Administration
Published in Michael M. Rothkopf, Jennifer C. Johnson, Optimizing Metabolic Status for the Hospitalized Patient, 2023
Michael M. Rothkopf, Jennifer C. Johnson
We see evidence of zinc deficiency quite often in malnourished individuals. For this reason, it is our practice to add additional zinc on top of the standard trace element ampule until the zinc levels become available. Zinc is involved in more than 200 enzymatic functions in the body. It is secreted with exocrine pancreatic fluid as a zymogen to activate digestive enzymes. Therefore, it is lost in increased amounts in any patient with bowel fluid loss, such as NGT suction, severe diarrhea or enterocutaneous fistula.
Digestive and Metabolic Actions of Dopamine
Published in Nira Ben-Jonathan, Dopamine, 2020
The pancreas is composed of two structurally and functionally distinct glands that cohabit in one organ [41]. The bulk of the pancreas is made of exocrine cells that produce digestive enzymes, while the islets of Langerhans produce several hormones, primarily associated with glucose metabolism, as discussed later in this chapter. Digestive enzymes produced by the exocrine pancreas include amylase, lipase, phospholipase, trypsinogen, and chymotrypsinogen. The latter two are proteolytic enzymes that are synthesized as inactive zymogens to prevent autodigestion and are activated by cleavage in the intestines. The pancreatic exocrine cells release their secretory products into small ducts that join to form the main pancreatic duct running along the length of the pancreas. The pancreatic duct merges with the bile duct in the head of the pancreas, and the content of both is released directly into the duodenum.
Macromolecular Absorption From The Digestive Tract In Young Vertebrates
Published in Károly Baintner, Intestinal Absorption of Macromolecules and Immune Transmission from Mother to Young, 2019
Enterokinase already is active in the proximal small intestine of young mammals, as indicated by the activation of trypsinogen. Enterokinase activity is not suppressed by the colostral inhibitor,51 which affects only the product of the reaction, namely, the activated trypsin. The remainder of the pancreatic zymogens (chymotrypsinogens, proelastase, procarboxypeptidases, and prophospholipases) are activated by trypsin, and in vitro addition of excess trypsin inhibitor suppresses these secondary reactions. The requirement of trypsin for the activation of zymogens may explain the wider occurrence of trypsin inhibitors than any other protease inhibitor in nature; however, chemical causes may also underlie the phenomenon. We have no experimental proof for the in vivo inhibition of activation of zymogens by any of the trypsin inhibitors.
Epithelial damage in the cystic fibrosis lung: the role of host and microbial factors
Published in Expert Review of Respiratory Medicine, 2022
Arlene M. A. Glasgow, Catherine M. Greene
MMPs are potent ECM-degrading proteases but their targets also include cytokines, growth factors, other proteases, antiproteases, clotting factors, and cell–cell adhesion molecules [103]. They are found to be increased and actively involved in inflammation, tissue remodeling, and repair. Cytokines such as IL-1β and TNFα can induce MMP transcription [104]. They are then synthesized as inactive zymogens that require cleavage of their pro-domain to become activated. Mediators of this activation include the active form of the MMP itself (auto-activation), or other proteases, e.g. NSPs are known to activate MMP-9 and MMP-12 [104,105]. Inhibition of MMP activity occurs via the four TIMP molecules (TIMPs 1–4) and also less specific inhibitors such as alpha-2 macroglobulin [103]. The actions of MMPs can be both pro- and anti-inflammatory, depending on the cellular or pathological context [106]. Whilst the full extent of MMP activity in CF pathogenesis is still a developing picture, MMP-2, −7, −8, −9, −10 and −12 have all been found increased in the CF lung and have several known functions of relevance.
Trypsinogen and chymotrypsinogen: potent anti-tumor agents
Published in Expert Opinion on Biological Therapy, 2021
Aitor González-Titos, Pablo Hernández-Camarero, Shivan Barungi, Juan Antonio Marchal, Julian Kenyon, Macarena Perán
The pancreas plays a very important role in the digestive function through the secretion of several enzymes necessary for the degradation of nutrients. These enzymes are secreted by acinar cells as zymogens (inactive forms also known as (pro)enzymes) [3]. Once secreted, they are transferred to the small intestine where they are activated. The most studied zymogens are Trypsinogen and Chymotrypsinogen. In the case of Trypsinogen, it is activated to Trypsin in the small intestine by enterokinase. Once activated, it is capable of activating the rest of the pancreatic zymogens, including Chymotrypsinogen into Chymotrypsin [4]. A failure in the production of these proteins can cause poor absorption of nutrients, the most common diseases that lead to exocrine pancreatic insufficiency are chronic pancreatitis and cystic fibrosis [5].
A novel anticancer chromeno-pyrimidine analogue inhibits epithelial-mesenchymal transition in lung adenocarcinoma cells
Published in Toxicology Mechanisms and Methods, 2021
Venkateswarareddy Nallajennugari, Sankar Pajaniradje, Srividya Subramanian, Suhail Ahmad Bhat, Parthasarathi D, Savitha Bhaskaran, Syed Ali Padusha M, Rukkumani Rajagopalan
Matrix metalloproteinases such as MMP-2 and MMP-9 belong to the family of zinc-dependent proteases (Chia et al. 2014). These mainly occur in the zymogen form. Upon activation through hydrolysis, they degrade the basement membrane of the extracellular matrix (ECM). This degradation is important for facilitating the penetration of ECM by tumor cells and helps in cancer cell movement (Zhang et al. 2014). It was shown that activity of both MMP-2 and MMP-9 promotes invasion, and thereby metastasis of cancer cells (Safranek et al. 2009). Collagens of type IV, V, VI, and X and gelatins are degraded by MMP-2 when activated (Merchant et al. 2017). Similarly, MMP-9, when activated, degrades fibronectins and collagens of type IV (Li et al. 2013). Expression of MMP-2 and MMP-9 is exceptionally high in metastatic cancer cells (Parsons et al. 1998) and actively involved in tumor invasion and metastasis (Fang et al. 2003). Gelatin zymography assay was performed to investigate whether the decreased migrating potential, confirmed through wound healing assay, is due to inhibition of MMP activity. Higher activity of MMP-9 and MMP-2 in untreated cells compared to their activity in the treated A549 cells indicated that anti-metastatic action of the drug was effected via decreased activity of MMPs.