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Allergic Contact Dermatitis from Rubber and Plastic Gloves
Published in Robert N. Phalen, Howard I. Maibach, Protective Gloves for Occupational Use, 2023
Guanidine is a rubber accelerator and a common contact allergen found among healthcare workers. A study conducted in a Belgium hospital performed patch testing to highlight the role of 1,3-diphenylguanidine (DPG) as the culprit allergen in contact hand dermatitis to synthetic rubber gloves.46 Patch test data was collected from healthcare workers who developed contact hand dermatitis after wearing rubber gloves and reacted positively to glove samples and rubber additives. The study demonstrated that 86% reacted positively to DPG, 84% reacted positively to “carba mix” (containing diphenylguanidine [DPG], zinc dibutyldithiocarbamate [ZDBC], and zinc diethyldithiocarbamate [ZDEC]), and 30% reacted positively to thiuram mix. DPG was the most commonly identified allergen, far ahead of thiurams, which had previously been described as the most sensitizing accelerator. The use of DPG-free gloves is recommended.46,47
Neuropeptide Regulation of Ion Channels and Food Intake
Published in Tian-Le Xu, Long-Jun Wu, Nonclassical Ion Channels in the Nervous System, 2021
Inwardly rectifying potassium (Kir) channels include seven subfamilies named Kir1- Kir7. Activation of Kir channels causes hyperpolarization following potassium channel opening (Glaaser and Slesinger 2015). Kir subfamily Kir3 is better known as G protein-gated inwardly rectifying potassium channels (GIRKs). When bound by agonists, GPCR activation leads to inhibitory G protein-dependent opening of GIRK channels for the hyperpolarizing response on neurons. Agonist binding induces an exchange of guanidine diphosphate (GDP) for the activated guanidine triphosphate (GTP) by the Gαi/o subunit. Free GTP bound Gαi/o disassociates from the Gβ/γ subunit complex. The Gβ/γ binds to the GIRK channel and, with PIP2 as a cofactor, the channel opening allows potassium ions to cross the membrane of the cell. GDP-bound Gα re-associates with the Gβ/γ and the channel closes (Glaaser and Slesinger 2015). When GIRK channels are activated, efflux of positively charged potassium ions results in hyperpolarization. In the brain, a variety of intercellular signaling molecules such as neuropeptides can activate GIRK channels so long as the GPCR contains the Gi/o (Glaaser and Slesinger 2015). GPCR kinases inactivate GIRKs through the competitive binding of Gβ/γ (van den Pol 2012).
Acquired Encephalopathies
Published in Philip B. Gorelick, Fernando D. Testai, Graeme J. Hankey, Joanna M. Wardlaw, Hankey's Clinical Neurology, 2020
Herman Sullivan, Muhammad U. Farooq
Several organic metabolites accumulate in ESRD, including urea, uric acid, and guanidine products (guanidine, creatinine, guanidinosuccinic acid, and methylguanidine). Guanidine compounds activate excitatory NMDA receptors and inhibit GABA receptors, leading to myoclonus and seizures. Metabolic changes, such as acidosis, electrolyte abnormalities (hyponatremia, hyperkalemia, hypocalcemia, and hypermagnesemia), dysregulation of fluid status, and imbalance between excitatory and inhibitory pathways contribute to neuronal dysfunction.
Enhancement of the oral bioavailability of isopropoxy benzene guanidine though complexation with hydroxypropyl-β-cyclodextrin
Published in Drug Delivery, 2022
Yixing Lu, Liuye Yang, Wanying Zhang, Shiting Xie, Feifei Zhao, Xianfeng Peng, Zonghua Qin, Dongping Zeng, Zhenling Zeng
Given that guanidine has strong organic bases and a hydrophilic nature, guanidine compounds have been widely used in the treatment of various diseases and have become candidates for the further structural modification of new promising drugs (Sączewski & Balewski, 2013; Massimba-Dibama et al., 2015). Isopropoxy benzene guanidine (IBG), a new guanidine compound, which displayed potent bactericidal activity against multidrug-resistant Enterococci and clinical isolates of methicillin-resistant Staphylococcus aureus by targeting the cell membrane (Zhang et al., 2019, 2021). Furthermore, the combination of IBG and colistin has synergistic antibacterial effect on colistin-resistant Salmonella (Kong et al., 2022). IBG is expected to become a new antibacterial agent in the treatment of bacterial infections. However, its bioavailability is not optimal due to its limited aqueous solubility.
Preliminary in vitro and in vivo evaluation of specific activity of branched oligohexamethyleneguanidine hydrochloride
Published in Drug Development and Industrial Pharmacy, 2020
S. V. Beliakov, D. O. Shatalov, S. A. Kedik, A. V. Aydakova, N. A. Zasypkina
Guanidine derivatives have already been used for a long time as active substances for antiseptic drugs due to their extensive spectrum of antimicrobial action and low toxicity. Preparations based on polyhexamethylenguanidium salts retain their activity in a wide range of environmental conditions; they readily dissolve in water and prevent the formation of microbial biofilms. The mechanism of the antimicrobial action of polyguanidines is based on the destruction of ester bonds in lipids and lipopolysaccharide complexes of the microorganism cell membrane first leads to the suppression of aggression factors (plasmocoagulase, hyaluronidase, oxidation of glycolytic enzyme SH-groups), and subsequently to the death of infectious agents. Polyguanidines are capable of sharply converging with the surface of the bacterial cell due to electrostatic charge, and then disrupt its integrity by replacing the metal cations [2,3].
Amifampridine for the treatment of Lambert-Eaton myasthenic syndrome
Published in Expert Review of Clinical Immunology, 2019
Guanidine hydrochloride was the only drug approved for use in LEMS in the US until 2018 but was approved by the US Food and Drug Administration (FDA) prior to 1962 when only safety information was necessary for approval [37,38]. Guanidine acts on the presynaptic junction as a potassium channel blocker and, thus, is an ideal drug for symptomatic treatment of LEMS. It was mostly studied in case reports and has not been studied in randomized trials. Guanidine has been used in 47 LEMS cases and clinical improvement was reported in most cases [27]. Two papers reported a larger series, both of nine patients [31,32]. Improvement ranged from ‘slight to dramatic.’ Electrophysiological improvement was also reported in two studies. The most common side effects are gastrointestinal symptoms and distal paresthesia. The most serious, but rare, side reactions of guanidine are hematologic abnormalities and renal insufficiency, which seem to be dose-related [31]. Because of these rare side reactions, guanidine is precluded as general use in LEMS. Combination therapy of low-dose of guanidine (less than 1 g a day) with a liberal dose of pyridostigmine was beneficial in nine LEMS cases with an improvement in muscle strength and CMAP amplitude without any undue serious side reaction [31]. This suggests that combination therapy of low-dose guanidine and pyridostigmine can be used as an alternative therapy for LEMS when 3,4-DAP or 3,4-DAPP is not readily available or patients were not able to take 3,4-DAP or 3,4-DAPP.