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Medium Design for Cell Culture Processing
Published in Wei-Shou Hu, Cell Culture Bioprocess Engineering, 2020
Nucleosides and nucleic acid make up a very significant portion of a cell’s content, as they constitute the genome. Most cultured cells are diploid, although many industrial cell lines are multiploid. Nucleosides constitute all RNAs whose cellular content is higher than DNA. Additionally, free ribonucleotides, like ATP, ADP, and AMP, are present in relatively high abundance in the cell. In fast-growing cells, deoxyribonucleotides (deoxyadenosine, deoxyguanidine, deoxythymidine, deoxycytidine) and ribonucleotides (adenosine, guanidine, uridine, cytidine) must be synthesized sufficiently quickly or otherwise be supplied exogenously to sustain growth. Mammals have de novo synthesis pathways for making purines (adenosine and guanidine) and pyrimidines (uracil, cytidine, thymidine), although the major site of such synthesis is in the liver (Panel 7.16). Both bases (purine and pyrimidine) and nucleosides (base + ribose or deoxyribose, without phosphate) can be transported into cells from tissue fluid or culture medium. Cultured cells, notably cancer cells, can develop the capability to synthesize purines and pyrimidines. Nucleic acids, especially mRNAs, are subjected to degradation due to gene expression regulation and turned over rapidly in the cell. These degradation products, mostly nucleosides or nucleoside monophosphates, are recycled to nucleoside triphosphates through salvage pathways for incorporation into nucleic acids again.
Prospects of Nanotechnology in Brain Targeting Drug Delivery
Published in Bhaskar Mazumder, Subhabrata Ray, Paulami Pal, Yashwant Pathak, Nanotechnology, 2019
Srijita Chakrabarti, Probin Kr Roy, Pronobesh Chattopadhyay, Bhaskar Mazumder
It is well known that purine and pyrimidine nucleosides and their metabolic products are the nucleic acids such as deoxyribonucleic acid (DNA) and RNA precursors and participate in different biological brain processes. In general, nucleosides are synthesized endogenously via de novo synthetic pathways (Carver, 1999). However, a number of tissues, including the brain, are deficient in de novo nucleotide synthetic pathways and rely on the salvage of exogenous nucleosides to maintain nucleoside pools and to meet their metabolic demands (Fox and Kelley, 1978). Therefore, the brain is dependent on a continuous and balanced supply of purine and pyrimidine nucleoside constituents from both synthesis in situ and the blood. Nucleoside transport systems have only been identified in selected mammalian cells: macrophages, CP, microglia, leukemia cells, splenocytes, intestinal cells, and renal brush border membrane vesicles. Several nucleoside transport systems such as concentrative nucleoside transporters and equilibrative nucleoside transporters have been identified in the BBB and BCSFB. Early in vivo studies revealed that at the BBB, purine ribonucleosides cross from the blood to the brain by facilitated diffusion, whereas pyrimidine deoxyribonucleosides did not show appreciable uptake into the brain (Lee et al., 2001).
Articular Cartilage Pathology and Therapies
Published in Kyriacos A. Athanasiou, Eric M. Darling, Grayson D. DuRaine, Jerry C. Hu, A. Hari Reddi, Articular Cartilage, 2017
Kyriacos A. Athanasiou, Eric M. Darling, Grayson D. DuRaine, Jerry C. Hu, A. Hari Reddi
Gout is a buildup of uric acid crystals in the blood and synovial fluid, leading to inflammatory arthritis. This increase in uric acid levels in the blood can be due to a lack of uric acid excretion by the kidneys or increased dietary intake of foods high in purine, a uric acid precursor. Excessive alcohol consumption is also commonly associated with increased uric acid concentrations (Saker et al. 1967; Liberopoulos et al. 2004; Fam 2005; Zhang et al. 2006; Choi and Curhan 2007), although the role of alcohol in gout progression is increasingly being questioned (Hennigan and Terkeltaub 2007). Gout has been described since ancient times by both the Babylonians and Egyptians, with Hippocrates providing one of the classical descriptions in the fifth century BC, relating it to dietary intake of alcohol and certain foods. The most common joint affected is the first metatarsophalangeal joint (big toe). Other disorders associated with increased uric acid concentration include tophus formation (large MSU crystals) and renal calculi (Figure 3.7).
Advancement of corrosion inhibitor system through N-heterocyclic compounds: a review
Published in Corrosion Engineering, Science and Technology, 2023
Rashika Batra, Ashish Kumar Singh, Manjeet Singh, Sanjeeve Thakur, Balaram Pani, Savas Kaya
Purine, a heterocyclic compound having a general formula of C5H4N4. Purine primarily consists of two rings fused together: pyrimidine and imidazole. Purines can be functionalised or substituted with many groups to bring a variation in properties. Widely purines play the role in the structure formation of nucleic acids but their structural aspects led scientists to work on their ability to prevent corrosion. Jiang et al. investigated two purine derivatives for their ability to prevent corrosion namely 6-Furfurylaminopurine (FAP) and N-Benzoylaminopurine (N-BAP) for mild steel in 1M HCl. It was perceived that both the inhibitors slowed the rates of respective cathodic as well as anodic reactions, so behaved in mixed mode and adsorption type adopted was chemisorption. Additionally, EIS study revealed; N-BAP with highest inhibition efficiency of 97.0% among the two which further increased to 98.6% when subjected to 24 h immersion in 0.6 mM inhibitor concentration. N-FAP ligated to metal surface via 2 N of purine ring while N-BAP with 2 N and O of carbonyl [152].