Biological safety considerations
C M Langton, C F Njeh in The Physical Measurement of Bone, 2016
Fortunately, most tissue processing methods require washing in tap water or solvent between the different chemical treatments. Moreover, the quantities and concentrations used are such that there is little danger from adverse reactions during processing. The greatest risk arises from the concentrated chemicals during preparation and storage. Oxidizing agents must be kept away from acids and flammables.Acids must be kept away from solvents.Chemicals with particular incompatibilities such as methyl methacrylate and benzoyl peroxide must be segregated in storage.
Chemistries of Chemical Warfare Agents
Brian J. Lukey, James A. Romano, Salem Harry in Chemical Warfare Agents, 2019
Physical Properties: Chloropicrin is a colorless oil with a bp of 112°C, a mp of −69°C, and a pungent, stinging odor that has been described as anise-like. Its vapor pressure is ~20 mm/Hg at 20°C, and its molecular mass is 164 g/mol (Redeman et al., 1948). The oil has a density of 1.66 g/mL and a vapor density of 5.6 relative to that of air. Chloropicrin has low solubility in water (~2 g/L) but is quite soluble in typical organic solvents (chloroform, acetone, ethyl acetate, etc.) and a variety of organic compounds including, for example, benzoic acid and various resins. Although chloropicrin is nonflammable, contact with oxidizing agents may lead to fires or explosions. Exposure to high temperatures can produce toxic gases, including phosgene and carbon monoxide. Electron diffraction (Knudsen et al., 1966) and mass spectrometry (Murty et al., 2005) studies of chloropicrin have been reported in addition to the vibrational spectra of bromopicrin and chloropicrin (Mason et al., 1959).
Liquid Phase Sequence Analysis of Proteins/Peptides
Ajit S. Bhown in Protein/Peptide Sequence Analysis: Current Methodologies, 1988
If the sequencer has not been used for some time (a week or so), it is necessary to run a standard protein, e.g., sperm whale myoglobin or insulin, to check the performance and efficiency of the sequencer. The standard or unknown protein sample for automated degradation must be free of nonvolatile salts as well as denaturing agents. Large amounts tend to precipitate the protein and form an impermeable covering on the protein film inside the cup. Oxidizing agents and heavy metals interfere with the chemical reaction of the degradation and, therefore, cannot be tolerated even in trace amounts. Ammonium salts are undesirable, because ammonia reacts with PITC to form phenylthiourea.
New frontier radioiodinated probe based on in silico resveratrol repositioning for microtubules dynamic targeting
Published in International Journal of Radiation Biology, 2023
Ashgan F. Mahmoud, Mohamed H. Aboumanei, Walaa Hamada Abd-Allah, Mohamed M. Swidan, Tamer M. Sakr
In the radioiodination reactions, the adjustment of the reaction pH has great impact on the radioiodination yield as it highly affects the redox potential of the utilized oxidizing agent (Moustapha 2020). In this experimental study, the oxidizing agent (CAT) loosed some of its oxidizing power by raising the pH of the reaction mixture toward the alkaline medium. This may be justified by the CAT can be present in active forms (HOCl and H2OCl+) in acidic medium while the less reactive species (HOCl and ClO) appeared in alkaline one (Rashed et al. 2014). Figure 2(b) revealed that the potential pH which can achieve the maximum radioiodination yield (94.6 ± 1.66) is 5. At this pH, the maximum oxidizing power of CAT is attained which has the capability of oxidizing most of the iodine to iodonium (I+) facilitating the electrophilic substitution of H+ of the resveratrol ring by the iodonium (I+) (Mahmoud et al. 2020; Sanad 2021). By shifting the pH of the reaction mixture toward the highly acidic one, the radioiodination yield significantly reduced to be 77 ± 2.07 at pH 1. Furthermore, shifting the reaction pH toward the neutral and alkaline mediums lead to dwindling the radioiodination yield (87.2 ± 1.38 and 82 ± 1.03 at pH 7 and 9, respectively) that could be explained by the formation of undesirable oxidative forms of iodine (hypoiodite ion (IO−) and iodate (IO−3)) (Abdel-Ghany et al. 2013; Moustapha et al. 2013).
Potential protective effect of catechin on doxorubicin-induced cardiotoxicity in adult male albino rats
Published in Toxicology Mechanisms and Methods, 2022
Aml Salem Saleh Ahmed
Beside these ventricular alterations, continuing myocyte degeneration and abridged coronary reserve might be the causes of enzyme leakage (Afsar et al. 2017). Moreover, the mitochondria in the cardiac muscle contains cardiolipin, which has a high affinity to DOX, leading to DOX accumulation within the cardiac mitochondria, impairment of the respiratory chain, and induction of apoptotic death (Abdel-Daim et al. 2017). Mitochondrial enzymes (e.g. NADH dehydrogenase) act on DOX in such a way that the quinone ring undergoes redox cycling between quinone and semiquinone states. During this process, electrons are generated and captured by oxidizing agents, including oxygen, which then initiate a chain reaction leading to the generation of ROS. Cytochrome P450 reductase and xanthine oxidase also have been found to catalyze the reduction of anthraquinone to a semiquinone free radical. DOX has the ability to suppress cytochrome P450, stimulating its own metabolism and thus could accelerate its elimination and increase the production of reactive toxic metabolites (Khan et al. 2014).
Cyanosis, hemolysis, decreased HbA1c and abnormal co-oximetry in a patient with hemoglobin M Saskatoon [HBB:c.190C > T p.His64Tyr]
Published in Hematology, 2021
Eva-Leonne Göttgens, Kristian Baks, Cornelis L. Harteveld, Kristel Goossens, Adriaan J. van Gammeren
In Hb M disease, treatment with both MB and ascorbic acid is ineffective because the ferric state in Hb M is stabilized. The Hb M structural variants are unstable or characterized by decreased oxygen affinities rather than other causes of methemoglobinemia, such as oxidative stress or enzymatic deficiency (CYB5R3). Treatment with MB would be undesirable, because as an oxidating agent, MB itself poses a risk of hemolytic anemia and could exacerbate methemoglobinemia. Exposure to any oxidizing agent should be avoided since these patients exhibit an increased risk of progression to symptomatic methemoglobinemia. Since there are no effective treatment options for patients with Hb M disease, counseling should focus on reassuring the patient about their benign condition and offering genetic testing to first-degree relatives.
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