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Prophylaxis and Chemotherapy
Published in Ronald Fayer, Lihua Xiao, Cryptosporidium and Cryptosporidiosis, 2007
Heather D. Stockdale, Jennifer A. Spencer, Byron L. Blagburn
HAART increases CD4+ T-cell counts and inhibits viral replication using a combination of nucleoside and non-nucleoside reverse transcriptase inhibitors (NNRTIs) and HIV protease inhibitors (Table 9.2) (Cacciò and Pozio, 2006). In treating cryptosporidiosis with HAART, an NNRTI or protease inhibitor (PI) is normally used in conjunction with two or more nucleoside reverse transcriptase inhibitors (NRTIs) (Ives et al., 2001). Nucleoside analogs or NRTIs, target reverse transcriptase via competitive binding and inhibit DNA synthesis (Hoffmann and Mulcahy, 2006b). NNRTI also target reverse transcriptase, binding noncompetitively and blocking nearby active sites. This will slow DNA synthesis (Hoffmann and Mulcahy, 2006a). PIs inhibit HIV protease and proteolytic splicing, preventing the viral particles from becoming infective (Hoffmann and Mulcahy, 2006c). Cryptosporidiosis becomes chronic in immunocompromised patients with CD4+ T-cell counts lower than 180/μL (Carr et al., 1998) and life threatening in patients with CD4+ T-cell counts lower than 50/μL (Hoffmann, 2006). In these patients, improving the immune system to levels comparable to a healthy individual with HAART results in self-limiting diarrhea and resolution of cryptosporidiosis (Hoffmann, 2006). A study involving more than 3000 HIV-infected patients, over a 5-year period, undergoing treatment with antiretroviral combinations of NRTIs and PIs, showed a decreasing incidence of opportunistic infections and death. The incidence of cryptosporidiosis decreased from 0.8/100 patients to 0.1/100 patients (Moore and Chaisson, 1999).
Anti-HIV Agents
Published in Mihai V. Putz, New Frontiers in Nanochemistry, 2020
The classes of therapeutical agents are: Entry inhibitors (fusion inhibitors) – EI.Reverse-transcriptase inhibitors (nucleoside analogs – NRTI, nonnucleoside analogs – NNRTI, and nucleotide analogs – NtRTI).Integrase inhibitors – INSTIs.Protease inhibitors – PI.Maturation inhibitors – MI.
Principles and Techniques for Deoxyribonucleic Acid (DNA) Manipulation
Published in Hajiya Mairo Inuwa, Ifeoma Maureen Ezeonu, Charles Oluwaseun Adetunji, Emmanuel Olufemi Ekundayo, Abubakar Gidado, Abdulrazak B. Ibrahim, Benjamin Ewa Ubi, Medical Biotechnology, Biopharmaceutics, Forensic Science and Bioinformatics, 2022
Nwadiuto (Diuto) Esiobu, Ifeoma M. Ezeonu, Francisca Nwaokorie
In the nucleotide structure, the central sugar moiety is connected to the nitrogenous base by a bond between its C-1 carbon atom and the N-1 atom of a pyrimidine or the N-9 atom of a purine as shown in Figure 1.1e. The sugar and base of a nucleotide are together referred to as a nucleoside. The addition of a phosphate makes it a nucleotide. Both DNA and RNA are therefore polynucleotides, because they are polymers of nucleotide subunits. Free unincorporated nucleotides exist as triphosphates, with three phosphate groups, but during incorporation into the nucleic acid chain, only one phosphate group is incorporated, while two phosphates are released as pyrophosphate (PPi).
Selective extraction of cordycepin from Cordyceps militaris – optimisation, kinetics and equilibrium studies
Published in Indian Chemical Engineer, 2022
Chayanid Sornchaithawatwong, Naphaphan Kunthakudee, Niti Sunsandee, Prakorn Ramakul
Nucleosides, such as uridine, guanosine, adenosine and cordycepin, comprise the main compounds and demonstrate several pharmacological activities [11]. Among these compositions, cordycepin is the most versatile compound because it has many pharmacological benefits [3,4] such as anti-bacterial, anti-tumour, anti-metastatic, anti-viral, anti-inflammatory, immunomodulatory and obvious synergies with cyclophosphamide [12–15].
A comprehensive screening shows that ergothioneine is the most abundant antioxidant in the wild macrofungus Phylloporia ribis Ryvarden
Published in Journal of Environmental Science and Health, Part C, 2018
Hengqiang Zhao, Minmin Zhang, Qian Liu, Xiaoli Wang, Ruixuan Zhao, Yanling Geng, Tityee Wong, Shengbo Li, Xiao Wang
A comprehensive screening and identification method of polar and non-polar antioxidants based on HILIC/RP-HPLC-DPPH assay coupled to ESI-Q-TOF/MS for the antioxidants discovery is presented. This method is rapid and efficient. As many as 46 compounds with antioxidant activity are detected from P. ribis. DPPH, a stable free-radical, is a common dye used for antioxidant detection.26,27,40–42,44,46,47 However, we caution the use of a single dye for antioxidant discovery. For example, DPPH is a poor indicator for some antioxidants such as inosine, p-hydroxybenzoic acid, and naringenin (Table 3). In fact, Table 3 shows that the abilities to scavenge DPPH and the OH radicals by an antioxidant are not necessarily proportional. We also noticed that ergothioneine is abundant in P. ribis. Ergothioneine (2-mercaptohistidine trimethylbetaine) has been known for more than a century and the compound has been reviewed by a number of authors.37–39,49–51 This water-soluble thione compound is synthesized by some bacteria and fungi. Many animals, including humans, store up a high level of this compound in the body via a specific organic cation transporter, SLC22A4. Once transported into the body, the half-life of ergothioneine is very long.51,52 Numerous in vitro assays have demonstrated the cytoprotective capabilities of this compound as a possible mitochondrial-targeted antioxidant. However, the physiology and mechanism of this compound in human is still not clear. P. ribis is also rich in adenosine (Table 3). Adenosine is a nucleoside. In addition to its roles in DNA, secondary messenger, and energy metabolism, adenosine can regulate blood flow through vasodilation.53 We also reported that there are some toxins (ergosterol and cerevisterol) in P. ribis. In view of its diverse composition, P. ribis as herbal medicine should be used with caution.