China
Africa
Explore chapters and articles related to this topic
Stroke
Published in Henry J. Woodford, Essential Geriatrics, 2022
Aspirin 300 mg daily should be commenced as soon as possible and continued for the first two weeks or until the time of discharge (whichever occurs sooner) after an ischaemic stroke. It can be given rectally or via a nasogastric tube, if required. After this time, it can be switched to clopidogrel 75 mg daily (unless anticoagulation is being commenced). A proton pump inhibitor can be co-prescribed if there is concern about gastric irritation. Use clopidogrel initially if aspirin is contraindicated.
Implication of Mitochondrial Coenzyme Q10 (Ubiquinone) in Alzheimer’s Disease *
Published in Abhai Kumar, Debasis Bagchi, Antioxidants and Functional Foods for Neurodegenerative Disorders, 2021
Sayantan Maitra, Dibyendu Dutta
Fe3+accepts electron and is oxidized to Fe2+. The system also acts as a proton pump. It is believed that four protons are pumped across the mitochondrial membrane during the oxidation process.
Application of Bioresponsive Polymers in Drug Delivery
Published in Deepa H. Patel, Bioresponsive Polymers, 2020
Manisha Lalan, Deepti Jani, Pratiksha Trivedi, Deepa H. Patel
Poly(methacrylic acid-co-methyl methacrylate) (Eudragit L, S, and F), hydroxypropylmethylcellulose phthalate and HPMC acetate succinate, they have carboxyl groups on the polymer side chains. These polymers are insoluble at low gastric pH but soluble at neutral intestinal pH. There are countless research studies and even significant number of products in the market which are based on such polymers. They are very apt for acid-labile products and offer a cost-effective solution to drug delivery issues. The proton pump inhibitors are a group of drugs which is well known for its acid sensitivity have been extensively investigated for such applications. A number of formulations like enteric-coated tablets, capsules, beads, granules, etc., have been developed. Not even small molecules but large molecules like bovine serum albumin (BSA) has also been encapsulated in such enteric-coated microspheres which displayed negligible drug release at pH 1.0 but ensure unimpeded release at pH 6.8.
Diagnostic performance of endoscopy for subsquamous extension of superficial adenocarcinoma of the esophagogastric junction
Published in Scandinavian Journal of Gastroenterology, 2023
Kazunori Takada, Yohei Yabuuchi, Tatsunori Minamide, Yoichi Yamamoto, Masao Yoshida, Yuki Maeda, Noboru Kawata, Kohei Takizawa, Yoshihiro Kishida, Sayo Ito, Kenichiro Imai, Kinichi Hotta, Hirotoshi Ishiwatari, Hiroyuki Matsubayashi, Hiroyuki Ono
All white-light endoscopic images, chromoendoscopy images following dyeing with indigo carmine, and narrow-band images with and without magnifying endoscopy were reviewed. Gastric atrophy (no atrophy, closed type or open type), longitudinal location (tumor center above, on or below the EGJ), circumferential location (anterior wall, right wall, posterior wall, left wall or circumferential), tumor size, macroscopic type (flat type, 0-IIa and 0-IIb; depressed type, 0-IIc and 0-IIa + IIc; and protruded type, 0-I and 0-I + IIa), and the presence of Barrett’s esophagus were evaluated. Gastric atrophy was diagnosed as the presence of a pale color, increased visibility of the mucosal vessels and a loss of the gastric folds [23] and subclassified according to the Kimura-Takemoto classification system [24]. The Helicobacter pylori (H. pylori) infection status was evaluated using H. pylori IgG antibody testing (cut-off value: 10 U/mL). Data on medication with proton pump inhibitor (PPI) were collected. Barrett’s esophagus was defined as an endoscopically-confirmed columnar epithelial metaplasia continuously extending from the stomach to the esophagus [25].
Clinical pharmacology of antiplatelet drugs
Published in Expert Review of Clinical Pharmacology, 2022
Georg Gelbenegger, Bernd Jilma
Proton pump inhibitors (PPI) are known CYP2C19 substrates and show different potency to inhibit CYP2C19 [82]. PPIs are often co-administered with aspirin and P2Y12 inhibitors to prevent gastrointestinal bleeding. Omeprazole, a widely used PPI, is metabolized to hydroxyomeprazole and omeprazole sulfate primarily by CYP2C19 and CYP3A4 [83]. However, it shows a greater affinity for CYP2C19 and therefore has a greater potential for drug-drug interactions mediated by CYP2C19 [84]. Clopidogrel relies heavily on hepatic bioactivation by CYP2C19, and concomitant use with omeprazole has consistently been shown to attenuate the antiplatelet effect of clopidogrel [85–90]. In contrast, pantoprazole does not attenuate clopidogrel responsiveness [91]. A meta-analysis of >150.000 patients indicates that proton pump inhibitor use was associated with an about 30% increase in major cardiovascular events, while gastrointestinal bleeding risk was reduced by about 50% [92].
Protective effect of the solvent extracts of Portulacca oleracea against acidified ethanol induced gastric ulcer in rabbits
Published in Drug and Chemical Toxicology, 2022
Muhammad Shah Zeb Jan, Waqar Ahmad, Atif Kamil, Mir Azam Khan, Maqsood Ur Rehman, Irfan ullah, Muhammad Saeed Jan
Moreover for the mechanistic study, three different pathways were determined. Histamine which is the main mediator of gastric acid secretion, triggers a chain of events which damage the mucosa (Mahmood et al.2005). Histamine increase gastric acid secretion via H2-receptors that are coupled to G-protein system. Stimulation of adenyl cyclase increases cAMP level, which is compulsory for activation of protein kinases. The protein kinases cause the phosporylation of certain phosphatases and activate the proton pump for the production of HCl (Mesia-Vela et al.2002). The oral administration of P. oleracea extracts reduced the histamine level which is the main pathway for blockade of gastric acid secretion. Moreover, EAF at high dose (400 mg/kg, p.o.) inhibited H+K+ATPase enzyme in comparison with positive control group. The H+K+ATPase enzyme which is also known as proton pump, that exchange protons (H+) and potassium (K+) ions across the plasma membrane of stomach and play vital role in acid formation (Gumz et al.2010). Similarly, acidified ethanol can also augment the production of ROS i.e., superoxide anion and hydroxyl radicals (Bailey 2003). ROS react with cellular lipids and form lipid peroxides. An effective indicator of oxidative stress is MDA, the major metabolite of lipid peroxidation (Rouhollahi et al.2014). This study showed that EAF at high dose (400 mg/kg, p.o.) prevented gastric ulceration by reducing MDA production against acidified ethanol.