Gastric cells

Persons who have a congenital decrease in the number of gastric cells secreting intrinsic factor... 

Figure 3.1 A schematic representation of the control mechanism that stimulates gastric acid secretion, and the intervention points used to treat ulcers. The parietal cells and gastric cells form part of the epithelial cell lining of the stomach. Histamine release is usually triggered as part ofthe enteric nervous system response to distension of the stomach when food is eaten.

Interaction of the food with the gastric mucosal layer is the normal trigger for gastric cells to release gastrin, which is then carried by the bloodstream to the parietal cells. Calcium ions and cyclic AMP act as intracellular messengers in the transfer of the signal from the receptors to the proton pumps of parietal cells where the acid is generated. 

The process, once initiated, is self-sustaining and may become more accelerated with time because the atrophy and intestinal metaplasia are progressive lesions and lead to further loss of parietal cells and incrased bacterial colonization of the mucosa. The initial mutations transform gastric cells into mature intestinal-type cells. Further superimposed mutations transform metaplastic cells into progressively dysplastic cells and eventually into neoplastic cells. This is a process of loss of differentiation which implies a multihit phenomenon which could be explained on the basis of continued formation of minute amounts of nitroso compounds over many years. 

Fry Are you saying that the gastric cells have no internal release mechanisms ... 

Shibata, H., KimuraTakagi, I., Nagaoka, M., Hashimoto, S., Sawada, H., Ueyama, S., and Yokokura, T. (1999). Inhibitory effect of Cladosiphon fucoidan on the adhesion of Helicobacter pylori to human gastric cells. /. Nutr. Sci. Vitaminol. (Tokyo) 45, 325-336. 

It acts by increasing mucus production, slowing turnover of gastric cells and increasing regeneration of cells around ulcer. 

Cherifi, Y., Pigeon, C., Le Romancer, M., Bado, A., Reyl-Desmars, F., Lewin, M.J.M., 1992. Purification of a histamine H3 receptor negatively coupled to phosphoinositide turnover in the human gastric cell line HGT1. J. Biol. Chem. 267, 25315-25320. 

At least three types of ATP driven H+ pumps may be potentially involved in the regulation of pHi. These are (a) an electrogenic H+ translocating ATPase found in the mammalian distal nephron (b) an electroneutral K+-H+ exchange ATPase that is responsible for acid secretion by gastric cells and (c) a vacuolar H+-ATPase which is responsible for the low pH of endocytic vesicles. The vacuolar H+-ATPase can be inhibited by the macrolide antibiotic bafilomycin Al. The gastric K+-H+-ATPase is inhibited by antiulcer drugs such as omeprazole. 

Wada, A., Mori, N., Oishi, K., Hojo, H., Nakahara, Y., Hamanaka, Y., Nagashima, M., Sekine, I., Ogushi, K., Niidome, T., Nagatake, T., Moss, J., Hirayama, T. Induction of human (S-defensin-2 mRNA expression by Helicobacter pylori in human gastric cell line MKN45 cells on cag pathogenicity island. Biochem Biophys Res Commun 263 (1999) 770-774. 

Haber, P, Gentry, R Malt, K., Mirmiran-Yazdy, S.. Griecn.stein, R., and Ucbcr, C. (1996). Metabolism of alcohol by human gastric cells Relation to first-pass metaboLsm, Gns-troenterology 111. 863-870. 

Lee, 1. S. Nishikawa, A. Fmukawa, F. Kasahara, K. Kim, S. U., Effects of Selaginella tamariscina on in vitro tumor cell growth, p53 expression, Gi arrest and in vivo gastric cell proliferation, Cancer Lett., 1999, 144, 93-99. 

Some flavonoids have been shown both to inhibit and to stimulate production of prostaglandins in vitro [28, 212]. Flavone and flavanone induced PGE2 production in isolated gastric mucosal cells, but since these compounds did not stimulate the prostanoid production in gastric cells exposed to arachidonic acid, it is likely that both flavonoids enhance prostaglandin formation by acting as cofactors of cyclooxygenase [142]. 

Moreover, fucoidan is a fucan sulfate occurring in brown marine algae. Shibata et ah studied the inhibitory effect of Cladosiphon fucoidan on H. pylori adhesion to human stomach (Shibata et ah, 1999). Their researches proved that fucoidan inhibited bacterial binding to human gastric cell. It was also shown that this fucoidan blocks both Leb- and sulfatide-mediated attachment of H. pylori to gastric cells. 

Major Applications Recording materials, biosensors, regulating acidity in gastric cells, for biological silicification studies, 1 fluorescence lifetime characterization of lysosomal pH Safety/Toxicity No data available... 

Proteins are digested in the stomach and intestine under the influence of proteolytic enzymes. The stomach contains at least two enzymes— pepsin and renin— which are secreted by the mucosal cells in the form of zymogens. The gastric cell secretes pepsinogen, a long polypeptide molecule with no catalytic property. Pepsin is activated to pepsinogen within the gastric lumen under the influence of at least two factors the low pH of the medium, which is a result of hydro-... 

Human gastric adenocarcinoma cell line Hydrophobin Class II protein (CRL-173 9) conjugated to porous silicon particles. Stable in gastric fluid and hydrophobin coating allows it to attach to the gastric cells Sarparanta et al. (2012a)... 

---