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Cellular Injury Associated with Organ Cryopreservation: Chemical Toxicity and Cooling Injury
Published in John J. Lemasters, Constance Oliver, Cell Biology of Trauma, 2020
Gregory M. Fahy, Carla da Mouta, Latchezar Tsonev, Bijan S. Khirabadi, Patrick Mehl, Harold T. Meryman
DMSO is not the only component of our cryoprotectant formulae, and the toxic effects of propylene glycol and formamide are also of interest. Virtually nothing is known of the toxic mechanisms of either solute, but Figure 6demonstrates that whatever the mechanism of toxicity of formamide may be, it can be completely reversed by the addition of DMSO. This protection appears specific to formamide since addition of DMSO to ethylene diamine (a highly toxic glass-forming agent) or to 2,3-butanediol39 exacerbated rather than reduced injury. Acetamide, which differs from formamide only by the addition of a methyl group, is dramatically less toxic than formamide, and in fact, a toxic level of acetamide has not yet been found. Addition of DMSO to acetamide produced a net increase in injury at total concentrations similar to those found to be protective in the case of formamide. Since DMSO and formamide do not hydrogen bond with one another at the temperature of exposure pertinent to Figure 6, neutralization of formamide toxicity by DMSO must be via actions of these agents on a common cell constituent or constituents that remain to be identified.
Experimental perturbations to investigate cardiovascular physiology
Published in Neil Herring, David J. Paterson, Levick's Introduction to Cardiovascular Physiology, 2018
Neil Herring, David J. Paterson
Another way of physically manipulating an isolated cell without physical contact with the cell membrane, is through osmotic stress. This can cause the cell to swell or shrink and while this is useful for investigating the regulation of cell volume, it is not the same as manipulating the preload experienced by a myocyte in the intact organ. Changes in preload produce stretch between each end of the cell, together with a slight degree of curvature along its axis, rather than a change on whole-cell volume. Osmotic shock can also be used to produce detubulation in isolated myocytes, that is, loss of sarcolemma transverse tubule (T-tubule) invaginations, which is also observed in myocytes from failing hearts and may influence excitation- contraction coupling. This can be achieved by brief exposure to high concentrations of formamide (at 1800 mOsm/L), which produces a transient reduction in cell volume on perfusion. As formamide is membrane permeable, it then enters the cell dragging water, so the cell subsequently expands. During washout, the intracellular concentration of formamide is initially high so that water enters the cell, causing the rapid expansion that may cause the T-tubules to break from the surface membrane. While this is a useful model of manipulating the physical space between L-type Ca2+ channels and ryanodine receptors, it is clearly different to the chronic structural remodelling that occurs in myocytes of the failing heart.
Reproductive and Developmental Toxicity Studies by Cutaneous Administration
Published in Rhoda G. M. Wang, James B. Knaak, Howard I. Maibach, Health Risk Assessment, 2017
Rochelle W. Tyl, Raymond G. York, James L. Schardein
Most of the formamides tested have had no developmental toxicity potential when tested by the cutaneous route. While methylformamide has been teratogenic in the rat but not the rabbit, this may be related more to dosage than species differences. In the rat, methylformamide applied topically at doses of 200 mg/kg and higher on gestation days 11 and 12 or 12 and 13 caused encephalocele and inguinal hernias.99 Similar malformations, reduced fetal weight, and diminished viability were also recorded for this species when the chemical was administered orally.102 As with the acetamides, methylformamide did not elicit developmental toxicity in rabbits at a topical dose of 200 mg/kg.99
Nanoparticle-based chewable gels of praziquantel
Published in Pharmaceutical Development and Technology, 2023
M. Alejandra Gonzalez, M. Verónica Ramírez-Rigo, Noelia L. Gonzalez Vidal
The moisture content of the developed chewable gels was determined by Karl Fischer titration using a Metrohm Titrando 852 model, with associated software Tiamo version 2.2 (Methrom Schweiz, Zofingen, Switzerland). Approximately 0.1 g of chewable gel was dissolved in a solution consisting of anhydrous methanol and formamide, in a 1: 1 ratio. Formamide was used because it improves the solubility in methanol of polar substances and accelerates the extraction of water from solids at elevated temperatures. Molecular sieves of 0.3 nm were used for the conditioning of the cell, previously dried at 300 °C for 24 h. The reaction mixture was heated to 50 °C, to favour the dissolution of the sample, and then it was titrated with the titration reagent. The assay was performed fivefold.
Overcoming hydrolytic degradation challenges in topical delivery: non-aqueous nano-emulsions
Published in Expert Opinion on Drug Delivery, 2022
Arya Kadukkattil Ramanunny, Sachin Kumar Singh, Sheetu Wadhwa, Monica Gulati, Bhupinder Kapoor, Rubiya Khursheed, Gowthamarajan Kuppusamy, Kamal Dua, Harish Dureja, Dinesh Kumar Chellappan, Niraj Kumar Jha, Piyush Kumar Gupta, Sukriti Vishwas
Atanase and Reiss reported the preparation of stable non-aqueous emulsions by using PEG 400 and paraffin oil [30]. Powell et al. revealed a method of preparation of non-aqueous emulsions using a range of polar solvents including ethylene glycol, ethanol, propyl alcohol, iso-propyl alcohol, propylene glycol, dipropylene glycol, tripropylene glycol, butylene glycol, iso-butylene glycol, methyl propane diol, glycerin, sorbitol, PEG, polypropylene glycol mono alkyl ethers, polyoxyalkylene copolymers, and mixtures thereof [55]. As mentioned in section 2, formamide derivatives such as N-methyl formamide (NMF), DMF, DMSO, and dimethyl acetylamide (DMA) are also used in preparation of non-aqueous emulsions. Sakthivel et al. reported the preparation of non-aqueous emulsion of 3H-dehydroepiandrosterone in dodecane-formamide system stabilized by polysorbate 20 [56]. Formamide is a polar solvent that closely resembles water in terms of hydrogen bonding and dielectric constant [57]. However, its stability and toxicity are of great concern that limits its application in pharmaceuticals.
Targeting the TGF-β signaling pathway for fibrosis therapy: a patent review (2015–2020)
Published in Expert Opinion on Therapeutic Patents, 2021
Xuanyi Li, Ziang Ding, Zixuan Wu, Yinqiu Xu, Hequan Yao, Kejiang Lin
Representative molecules targeting SMAD that mediate negative feedback are shown in Table 7. Novartis AG primarily studies smurf-1 inhibitors of formamide. Smurf-1 belongs to the HECT family of E3 ubiquitin ligases. SMAD7 plays an important role in limiting EMT and collagen induction and is responsible for negative feedback inhibition, and inhibition of smurf-1 protects SMAD7 [96]. The general structural formula published in the document is as follows: the main body is formamide with pyrazole, triazole or isoxazole structure, in which R1 is mostly (C3-C6) alkyl or (C3-C6) cycloalkane, R2 is methyl, R3 is selected from polysubstituted cyclohexene and benzene ring, and can form azepine. Among them, 907,941 and 903,773 effectively inhibited smurf-1 activity (IC50 = 0.9 nM, 0.55 nM, respectively) [97–100]. According to the protective effect of SMAD-7, Petrash et al. from University of Colorado constructed a recombinant fusion protein TAT-PY-C-Smad7, containing the PY domain derived from Smad7. It inhibited expression of α-SMA in lens epithelial cells (LECs) in vitro and inhibit the activation of SMAD in LECs in vivo and is expected to be used for the treatment of ocular fibrosis [101].