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The Scientific Basis of Medicine
Published in John S. Axford, Chris A. O'Callaghan, Medicine for Finals and Beyond, 2023
Chris O'Callaghan, Rachel Allen
Genetic information is stored and transferred in the form of the nucleic acids deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). These molecules provide the necessary information for protein production. Like many biological molecules, nucleic acids are multimers of smaller units; which in this case are known as nucleotides. A set of four nucleotide components is used to generate DNA or RNA. Adenine (A), guanine (G) and cytosine (C) are common to both DNA and RNA. Thymine (T) is found in DNA but absent from RNA, with uracil (U) present in its place.
Haematological malignancy
Published in Peter Hoskin, Peter Ostler, Clinical Oncology, 2020
Chemotherapy will comprise high-dose cytosine arabinoside. Patients with CNS disease will also require cranial irradiation and intrathecal methotrexate but prophylactic CNS treatment is not generally recommended in contrast to that in ALL.
Biological Basis of Behavior
Published in Mohamed Ahmed Abd El-Hay, Understanding Psychology for Medicine and Nursing, 2019
A strand of DNA serves as a template for the synthesis of ribonucleic acid (RNA) molecules. There are four types of RNA, each encoded by its own type of gene. Messenger RNA serves as a template for the synthesis of protein molecules. DNA contains four bases (adenine, guanine, cytosine, and thymine). The order of those bases determines the order of corresponding bases along an RNA molecule (adenine, guanine, cytosine, and uracil). In turn, the order of bases along an RNA molecule determines the order of amino acids that compose a protein, e.g., if three RNA bases are, in order, cytosine, adenine, and guanine, then the protein adds the amino acid glutamine. If the next three RNA bases are uracil, guanine, and guanine, the next amino acid on the protein is tryptophan. In total, proteins consist of 20 amino acids, and the order of those amino acids depends on the order of DNA and RNA bases.
The use of IV vitamin C for patients with COVID-19: a case series
Published in Expert Review of Anti-infective Therapy, 2020
Raul Hiedra, Kevin Bryan Lo, Mohammad Elbashabsheh, Fahad Gul, Robert Matthew Wright, Jeri Albano, Zurab Azmaiparashvili, Gabriel Patarroyo Aponte
The inpatient mortality rate in this series was 12% with 17.6% rate of intubation and mechanical ventilation, respectively. On correlational analysis, only hypertension was significantly positively associated with need for mechanical ventilation (r = 0.491, p = 0.045), while age (r = 0.508, p = 0.037) and post treatment FiO2 requirements (r = 0.700, p = 0.002) were significantly positively associated with inpatient mortality. Analyses using paired T-tests showed significantly lower D-dimer and ferritin levels post treatment with vitamin C. FiO2 requirements also had a trend toward reduction but did not reach statistical significance (see Table 2). Further analyses of medications administered in combination with vitamin C showed no significant differences in terms of need for intubation and mortality among patients who received hydroxychloroquine, methylprednisolone, and/or tocilizumab. Of the three patients who needed intubation, one was on hydroxychloroquine and methylprednisolone, one was on methylprednisolone alone, and one was on hydroxychloroquine and tocilizumab. No adverse events directly related to the administration of vitamin C were recorded.
Chromosome aberration in typical biological systems under exposure to low- and high-intensity magnetic fields
Published in Electromagnetic Biology and Medicine, 2020
Emanuele Calabrò, Hit Kishore Goswami, Salvatore Magazù
Chromosomes are molecules composed of the deoxyribonucleic acid (DNA) that represents the genetic material of a living being. In human beings, there are 22 pairs of chromosomes and 2 sex chromosomes for a total of 46. DNA is an organic polymer composed of monomers that are called nucleotides. They consist of a phosphate group and a nitrogenous base linked to deoxyribose by the so-called N-glycoside bond. The nitrogenous bases that can be used in nucleotide formation are adenine, cytosine, guanine and thymine disposed in base pairs of adenine-thymine (A-T) and guanine-cytosine (G-C) that in aqueous solutions are linked one each other by hydrogen bonds forming a double helix structure because of the repulsions between the negative charge of phosphate groups. This double helix structure is bound to proteins (the histones) that have positively charged amino acids in order to bind the DNA which is negatively charged and is wrapped around the core of histone of eight protein subunits forming the nucleosome. About 200 base pairs of DNA are coiled around each histone. This coil is untwisted generating a negative superturn per nucleosome that is the active chromatin.
Comprehensive overview of the recently FDA-approved contraceptive vaginal ring releasing segesterone acetate and ethinylestradiol: A new year-long, patient controlled, reversible birth control method
Published in Expert Review of Clinical Pharmacology, 2019
The most critical component that accounts for the success of this new CVR is the new progestin segesterone acetate. Segesterone acetate is a 19-nor-progesterone derivative, known as 19-norpregn-4-ene-3,20-dione, 17-hydroxy-16-methylene-19-nonpregn-4-ene-3,20-dione acetate ester and 16-methylene-17α-acetoxy-19-nor-pregn-4-ene-3,20-dione (see Figure 3). Its molecule formula is C23H3004 (see Figure 3). It is a white or yellowish-white powder with a molecular weight of 370.5 Dalton. This compound has significant potency; only low doses are needed for ovulation suppression. However, it is rapidly metabolized when administered orally, so a slow release, transdermal or transmucosal delivery system, such as the contraceptive vaginal ring, represents an excellent delivery system to utilize its strengths [11].