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The cell and tissues
Published in Peate Ian, Dutton Helen, Acute Nursing Care, 2020
Both glycerol and fatty acids, the breakdown products of fats, are used as fuel for ATP production under normal circumstances. In fact, the liver and resting skeletal muscle will use them out of preference. The glycerol joins the pathway during glycolysis and contributes to the production of pyruvic acid. Fatty acids undergo a process leading to the production of acetyl coenzyme A.
Functions of the Liver
Published in Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal, Principles of Physiology for the Anaesthetist, 2020
Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal
The breakdown of glucose to carbon dioxide and water with the production of energy is called glycolysis. Glucose catabolism proceeds by two pathways, either by cleavage to trioses producing pyruvic acid and lactic acid (the Embden–Meyerhof pathway) or via oxidation and decarboxylation to pentose (hexose monophosphate shunt). The net energy gain from glycolysis is three molecules of ATP. Pyruvic acid enters the citric acid cycle by conversion to acetic acid with the loss of one molecule of CO2. The citric acid cycle generates 12 molecules of ATP for every molecule of acetic acid. In total, 38 molecules of ATP are produced by the aerobic breakdown of glucose to pyruvate and its incorporation into the citric acid cycle. Pyruvic acid can be formed from the metabolism of amino acids and fat. Glycolysis produces acetyl CoA, which is used as a substrate for lipogenesis and subsequently the production of triglycerides. Another important property of the liver is the formation of reduced nicotinamide adenine dinucleotide phosphate (NADPH) via the pentose phosphate pathway. Two NADPH molecules and ribose-5-phosphate are produced from one glucose molecule. NADPH is required for microsomal and mitochondrial hydroxylation of steroid hormones and biotransformation of many drugs.
Features of Lipid Metabolism in Diabetes Mellitus and Ischemic Heart Disease
Published in E.I. Sokolov, Obesity and Diabetes Mellitus, 2020
Under anaerobic conditions, glycolysis proceeds with the participation of a large number of enzymes. The glucose decomposes into pyruvic acid. The following are the basic biochemical stages of glycolysis:
Mitochondria as a key player in systemic lupus erythematosus
Published in Autoimmunity, 2022
Diana C. Quintero-González, Marcela Muñoz-Urbano, G. Vásquez
ATP production involves two processes with synergistic effects: glycolysis and oxidative phosphorylation (OXPHOS). Glucose is broken down and oxidized through glycolysis, resulting in four ATP molecules (two as net gain). Electrons released from glycolysis reduce nicotinamide adenine dinucleotide 1 (NAD1) to NADH1. Pyruvic acid, another product of glycolysis, enters the mitochondria in an oxygen-charged environment and is transformed into acetyl coenzyme A (CoA). CoA oxidation and other serial reactions in the Krebs cycle permit the generation of energy and compounds that carry hydrogen, including flavin adenine dinucleotide (FADH2) and NADH1 [13]. The OXPHOS reaction occurs in the electron transport chain (ETC), wherein hydrogen ions (H+) from NADH1/FADH2 on the MM are pumped to the intermembrane space through four respiratory complexes (in the order I, III, II, and IV), generating the mitochondrial transmembrane potential (MTP). Ultimately, the V complex, also known as ATP synthase, drives back the H+, leading to adenosine diphosphate phosphorylation and the formation of 34 ATP [14].
Safety considerations with new antibacterial approaches for chronic bacterial prostatitis
Published in Expert Opinion on Drug Safety, 2022
Gianpaolo Perletti, Alberto Trinchieri, Konstantinos Stamatiou, Vittorio Magri
The toxicity profile of linezolid is complex, and reports on adverse effects caused by this drug are not always unequivocal. Nevertheless, it is acknowledged that linezolid has a narrow therapeutic index and that long-term treatment with this drug may expose patients to the emergence of adverse events [75]. The effects causing major concerns are (i) serotonin syndromes, which are usually seen after several days of therapy, (ii) lactic acidosis, occurring after several weeks, (iii) peripheral and optic neuropathy seen after several months, and (iv) myelosuppression [76–78]. Most likely, linezolid can cause the two latter effects by targeting protein synthesis in mitochondrial ribosomes and by affecting the activity of mitochondrial complex IV [79–83]. As far as metabolic acidosis is concerned, the linezolid-associated impairment of mitochondrial enzymes in complex IV of the electron transfer chain may affect not only the chain itself but also the upstream Krebs cycle. This may cause the abnormal accumulation of pyruvic acid, which is in turn converted into lactic acid, whose excess is ultimately responsible for the onset of acidosis [84].
Repurposing metformin for covid-19 complications in patients with type 2 diabetes and insulin resistance
Published in Immunopharmacology and Immunotoxicology, 2021
Payam Hashemi, Shaghayegh Pezeshki
According to the investigations, glycolysis is the main metabolic pathway rather than mitochondrial pathway in inflammatory cells such as neutrophils, M1 macrophages, effector T cells, activated NK cells, and T helper 1, 17 [72,73]. Glycolysis can induce higher levels of inflammation due to more generation of ROS [74]. On the other hand, immunomodulatory cells such as M2 macrophages, regulatory and memory T cells are dependent on mitochondrial oxidation rather than glycolysis [72]. Electron transport chains of mitochondria have more ability to control oxidative stress of catalytic pathways compared with glycolysis [75–77]. Levels of mitochondrial oxidation of pyruvate (the main production of glycolysis) in inflammatory cells are lower than regulatory cells. So, inflammatory cells release more amounts of pyruvic acid into the circulation [78]. Generation of oxidative stress and inflammation in immune system is partially based on glycolysis [79]. Overactivity of immune system against the Covid-19 infection leads to damage of lung tissue including fibrosis, blood clots, endothelial dysfunction. These alternations may induce severe hypoxemia and ARDS in end stage of the infection [80].