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Toxicon: X Jun 2022Snakebite envenoming affects more than 250,000 people annually in sub-Saharan Africa. Envenoming by (boomslang) results in venom-induced consumption coagulopathy...
Snakebite envenoming affects more than 250,000 people annually in sub-Saharan Africa. Envenoming by (boomslang) results in venom-induced consumption coagulopathy (VICC), whereby highly abundant prothrombin-activating snake venom metalloproteinases (SVMPs) consume clotting factors and deplete fibrinogen. The only available treatment for envenoming is the monovalent SAIMR Boomslang antivenom. Treatment options are urgently required because this antivenom is often difficult to source and, at US$6000/vial, typically unaffordable for most snakebite patients. We therefore investigated the and preclinical efficacy of four SVMP inhibitors to neutralise the effects of venom; the matrix metalloproteinase inhibitors marimastat and prinomastat, and the metal chelators dimercaprol and DMPS The venom of exhibited an SVMP-driven procoagulant phenotype . Marimastat and prinomastat demonstrated equipotent inhibition of the SVMP-mediated procoagulant activity of the venom , whereas dimercaprol and DMPS showed considerably lower potency. However, when tested in preclinical murine models of envenoming using mixed sex CD1 mice, DMPS and marimastat demonstrated partial protection against venom lethality, demonstrated by prolonged survival times of experimental animals, whereas dimercaprol and prinomastat failed to confer any protection at the doses tested. The preclinical results presented here demonstrate that DMPS and marimastat show potential as novel small molecule-based therapeutics for snakebite envenoming. These two drugs have been previously shown to be effective against VICC in preclinical models, and thus we conclude that marimastat and DMPS should be further explored as potentially valuable early intervention therapeutics to broadly treat VICC following snakebite envenoming in sub-Saharan Africa.
PubMed: 35321116
DOI: 10.1016/j.toxcx.2022.100118 -
Environmental Toxicology and... May 2022The reaction between 2,3-dimercaptopropane-1-sulfonate (DMPS, unithiol) and four phenylarsonic(V) acids, i.e. phenylarsonic acid (PAA), 4-hydroxy-3-nitrophenylarsonic...
The reaction between 2,3-dimercaptopropane-1-sulfonate (DMPS, unithiol) and four phenylarsonic(V) acids, i.e. phenylarsonic acid (PAA), 4-hydroxy-3-nitrophenylarsonic acid (HNPAA), 2-aminophenylarsonic acid (o-APAA) and 4-aminophenylarsonic acid (p-APAA), is investigated in aqueous solution. The pentavalent arsenic compounds are reduced by DMPS to their trivalent analogs and instantly chelated by the vicinal dithiol, forming covalent As-S bonds within a five-membered chelate ring. The different types and positions of polar substituents at the aromatic ring of the arsonic acids influence the reaction rates in the same way as observed for reaction with glutathione (GSH), as well as the syn/anti molar ratio of the diastereomeric products, which was analyzed using time- and temperature-dependent nuclear magnetic resonance (NMR) spectroscopy. Addition of DMPS to the conjugate formed by a phenylarsonic(V) acid and the biologically relevant tripeptide GSH showed the immediate replacement of GSH by chelating DMPS, underlining the importance of dithiols as detoxifying agent.
Topics: Arsenicals; Chelating Agents; Glutathione; Magnetic Resonance Spectroscopy; Oxidation-Reduction; Unithiol; X-Ray Diffraction
PubMed: 35248761
DOI: 10.1016/j.etap.2022.103837 -
Anti-cancer Agents in Medicinal... 2022The objective of this study was to analyze the antitumor effect of BisBAL NP in a mouse melanoma model.
AIM
The objective of this study was to analyze the antitumor effect of BisBAL NP in a mouse melanoma model.
MATERIALS AND METHODS
The antitumor activity of BisBAL NP on murine B16-F10 melanoma cells was determined both in vitro (PrestoBlue cell viability assay and Live/Dead fluorescence) and in vivo, in a mouse model, with the following 15-day treatments: BisBAL NP, negative control (PBS), and cell-death control (docetaxel; DTX). Mouse survival and weight, as well as the tumor volume, were recorded daily during the in vivo study.
RESULTS
BisBAL NP were homogeneous in size (mean diameter, 14.7 nm) and bismuth content. In vitro, 0.1 mg/mL BisBAL NP inhibited B16-F10 cell growth stronger (88%) than 0.1 mg/mL DTX (82%) (*p<0.0001). In vivo, tumors in mice treated with BisBAL NP (50 mg/kg/day) or DTX (10 mg/kg/day) were 76% and 85% smaller than the tumors of negative control mice (*p<0.0001). The average weight of mice was 18.1 g and no statistically significant difference was detected among groups during the study. Alopecia was only observed in all DTX-treated mice. The survival rate was 100% for the control and BisBAL NP groups, but one DTX- treated mouse died at the end of the treatment period. The histopathological analysis revealed that exposure to BisBAL NP was cytotoxic for tumor tissue only, without affecting the liver or kidney.
CONCLUSION
BisBAL NP decreased the tumor growing in a mouse melanoma model without secondary effects, constituting an innovative low-cost alternative to treat melanoma.
Topics: Animals; Antineoplastic Agents; Bismuth; Cell Line, Tumor; Dimercaprol; Humans; Melanoma, Experimental; Mice; Nanoparticles; Organometallic Compounds
PubMed: 35168526
DOI: 10.2174/1871520622666220215124434 -
International Journal of Molecular... Feb 2022The increasing antibiotic resistance is a clinical problem worldwide. Numerous Gram-negative bacteria have already become resistant to the most widely used class of...
The increasing antibiotic resistance is a clinical problem worldwide. Numerous Gram-negative bacteria have already become resistant to the most widely used class of antibacterial drugs, β-lactams. One of the main mechanisms is inactivation of β-lactam antibiotics by bacterial β-lactamases. Appearance and spread of these enzymes represent a continuous challenge for the clinical treatment of infections and for the design of new antibiotics and inhibitors. Drug repurposing is a prospective approach for finding new targets for drugs already approved for use. We describe here the inhibitory potency of known detoxifying antidote 2,3-dimercaptopropane-1-sulfonate (unithiol) against metallo-β-lactamases. Unithiol acts as a competitive inhibitor of meropenem hydrolysis by recombinant metallo-β-lactamase NDM-1 with the K of 16.7 µM. It is an order of magnitude lower than the K for l-captopril, the inhibitor of angiotensin-converting enzyme approved as a drug for the treatment of hypertension. Phenotypic methods demonstrate that the unithiol inhibits natural metallo-β-lactamases NDM-1 and VIM-2 produced by carbapenem-resistant and bacterial strains. The 3D full atom structures of unithiol complexes with NDM-1 and VIM-2 are obtained using QM/MM modeling. The thiol group is located between zinc cations of the active site occupying the same place as the catalytic hydroxide anion in the enzyme-substrate complex. The sulfate group forms both a coordination bond with a zinc cation and hydrogen bonds with the positively charged residue, lysine or arginine, responsible for proper orientation of antibiotics upon binding to the active site prior to hydrolysis. Thus, we demonstrate both experimentally and theoretically that the unithiol is a prospective competitive inhibitor of metallo-β-lactamases and it can be utilized in complex therapy together with the known β-lactam antibiotics.
Topics: Carbapenems; Drug Repositioning; Drug Resistance, Bacterial; Gene Expression Regulation, Bacterial; Gene Expression Regulation, Enzymologic; Klebsiella pneumoniae; Models, Molecular; Protein Conformation; Pseudomonas aeruginosa; Quantitative Structure-Activity Relationship; Unithiol; beta-Lactamase Inhibitors; beta-Lactamases
PubMed: 35163756
DOI: 10.3390/ijms23031834 -
Langmuir : the ACS Journal of Surfaces... Nov 2021Dopamine (DA), a naturally occurring neurotransmitter, plays a crucial role in the function of the mammalian nervous system. DA-lipid-membrane interaction is inevitable...
Dopamine (DA), a naturally occurring neurotransmitter, plays a crucial role in the function of the mammalian nervous system. DA-lipid-membrane interaction is inevitable during the neurotransmission process. In this report, we have studied the interaction of DA with anionic 1,2-dimyristoyl--glycero-3-phospho-l-serine (DMPS), neutral (zwitterionic) 1,2-dimyristoyl--glycero-3-phosphocholine (DMPC), and synaptic membrane-mimicking mixed DMPC/DMPS (3:1 molar ratio) model multilamellar vesicle (MLV) membranes. Differential scanning calorimetry (DSC) studies suggest a strong specific interaction of DA with the anionic DMPS membrane, a weak interaction with the zwitterionic DMPC membrane, and a moderate interaction with the mixed DMPC/DMPS (3:1) membrane. The intrinsic fluorescence of DA was used as a new approach to gain a molecular-level understanding of DA-lipid-membrane interaction. Toward this end, a detailed photophysical study of DA, including its steady-state fluorescence anisotropy and fluorescence lifetime, was undertaken for the first time. The partition coefficient, location, and distribution of DA in the DMPS and DMPC model membranes were studied by employing intrinsic fluorescence. The effect of DA on the phase transition of the model membranes was also examined using the intrinsic fluorescence of DA. Zeta potential studies suggest a strong electrostatic interaction of DA with the anionic DMPS membrane and a nonspecific, relatively weak interaction of DA with the zwitterionic DMPC membrane. In addition, we observed cholesterol-induced DA expulsion from both DMPS and DMPC membranes. We believe that this work will provide a more in-depth understanding of DA-membrane interaction at a molecular level.
Topics: Anions; Dimyristoylphosphatidylcholine; Dopamine; Lipid Bilayers; Unithiol
PubMed: 34732050
DOI: 10.1021/acs.langmuir.1c02184 -
Pharmaceutics Oct 2021Actinium-225 (Ac) is a promising radionuclide used in targeted alpha therapy (TAT). Although Ac labeling of bifunctional chelating ligands is effective, previous in vivo...
Evaluation of Aminopolycarboxylate Chelators for Whole-Body Clearance of Free Ac: A Feasibility Study to Reduce Unexpected Radiation Exposure during Targeted Alpha Therapy.
Actinium-225 (Ac) is a promising radionuclide used in targeted alpha therapy (TAT). Although Ac labeling of bifunctional chelating ligands is effective, previous in vivo studies reported that free Ac can be released from the drugs and that such free Ac is predominantly accumulated in the liver and could cause unexpected toxicity. To accelerate the clinical development of Ac TAT with a variety of drugs, preparing methods to deal with any unexpected toxicity would be valuable. The aim of this study was to evaluate the feasibility of various chelators for reducing and excreting free Ac and compare their chemical structures. Nine candidate chelators (D-penicillamine, dimercaprol, Ca-DTPA, Ca-EDTA, CyDTA, GEDTA TTHA, Ca-TTHA, and DO3A) were evaluated in vitro and in vivo. The biodistribution and dosimetry of free Ac were examined in mice before an in vivo chelating study. The liver exhibited pronounced Ac uptake, with an estimated human absorbed dose of 4.76 Sv/MBq. Aminopolycarboxylate chelators with five and six carboxylic groups, Ca-DTPA and Ca-TTHA, significantly reduced Ac retention in the liver (22% and 30%, respectively). Significant Ac reductions were observed in the heart and remainder of the body with both Ca-DTPA and Ca-TTHA, and in the lung, kidney, and spleen with Ca-TTHA. In vitro interaction analysis supported the in vivo reduction ability of Ca-DTPA and Ca-TTHA. In conclusion, aminopolycarboxylate chelators with five and six carboxylic groups, Ca-DTPA and Ca-TTHA, were effective for whole-body clearance of free Ac. This feasibility study provides useful information for reducing undesirable radiation exposure from free Ac.
PubMed: 34683999
DOI: 10.3390/pharmaceutics13101706 -
BMJ Case Reports Sep 2021A 38-year-old man presented at the emergency department with abdominal pain, vomiting, generalised weakness and altered consciousness. He had been ingesting opioids for...
A 38-year-old man presented at the emergency department with abdominal pain, vomiting, generalised weakness and altered consciousness. He had been ingesting opioids for over 5 years and had several past hospital admissions for abdominal pain. His investigations showed deranged liver function tests, anaemia and basophilic stippling on the peripheral blood smear. Further investigations revealed a significant increase in the serum lead level. We started chelation with peroral penicillamine 250 mg every 6 hours for 2 days and switched to intramuscular dimercaprol 4 mg/kg every 12 hours and intravenous calcium ethylenediamine tetraacetic acid 50 mg/kg in two divided doses daily for the next 5 days. We then discharged him home; he had become clinically stable by that time. We repeated his lead level and followed him up in the clinic. In this report, we emphasise the consideration of lead toxicity in opioid abusers and bring to attention a rare way of lead chelation in resource-limited settings.
Topics: Abdominal Pain; Adult; Analgesics, Opioid; Brain Diseases; Humans; Lead; Lead Poisoning; Male
PubMed: 34544696
DOI: 10.1136/bcr-2020-240977 -
Technology in Cancer Research &... 2021To investigate the efficacy of a formula comprising arsenic trioxide and dimercaprol (BAL-ATO) as a radiosensitizing agent in model mice with pancreatic cancer...
OBJECTIVE
To investigate the efficacy of a formula comprising arsenic trioxide and dimercaprol (BAL-ATO) as a radiosensitizing agent in model mice with pancreatic cancer xenografts.
METHODS
Female BALB/c nude mice bearing SW1990 human pancreatic cancer xenografts were divided into four treatment arms, including control, radiotherapy (RT), BAL-ATO, and RT + BAL-ATO groups. Survival and tumor volume were analyzed. We also assessed apoptosis in tumor samples by live imaging and detected hypoxia by confocal laser microscope observation. We further investigated the mechanisms of BAL-ATO action in RT by detecting affected proteins by western blot and immunohistochemistry assays.
RESULTS
Median survival was significantly longer in the RT + BAL-ATO group (64.5 days) compared with the control (49.5 days), RT (39 days), and BAL-ATO (48 days) groups ( 0.001). RT + BAL-ATO inhibited the growth of tumors in mice by 73% compared with the control group, which was significantly higher than the rate of inhibition following RT alone (59%) ( < 0.01). Further analysis showed an improved microenvironment in terms of hypoxia in tumors treated with BAL-ATO alone or RT + BAL-ATO. Expression of signaling molecules associated with pancreatic cancer stem cells, including CD24, CD44, ALDH1A1, Gli-1, and Nestin, was detected in tumors treated with BAL-ATO alone or in combination with RT.
CONCLUSION
These data suggest that BAL-ATO function as a radiosensitizer in mice with pancreatic cancer xenografts, via mechanisms involving hypoxia reduction and inhibition of signaling pathways associated with pancreatic cancer stem cells. BAL-ATO may thus be a promising radiosensitizing agent in patients with pancreatic cancer.
Topics: Animals; Antineoplastic Agents; Arsenic Trioxide; Biomarkers; Cell Line, Tumor; Cell Proliferation; Dimercaprol; Disease Models, Animal; Drug Combinations; Drug Compounding; Female; Humans; Mice; Pancreatic Neoplasms; Prognosis; Radiation Tolerance; Radiation-Sensitizing Agents; Signal Transduction; Treatment Outcome; Xenograft Model Antitumor Assays
PubMed: 34433326
DOI: 10.1177/15330338211036324 -
Frontiers in Immunology 2021Palearctic vipers are medically significant snakes in the genera , and which occur throughout Europe, Central Asia, Near and Middle East. While the ancestral condition... (Comparative Study)
Comparative Study
Palearctic vipers are medically significant snakes in the genera , and which occur throughout Europe, Central Asia, Near and Middle East. While the ancestral condition is that of a small-bodied, lowland species, extensive diversification has occurred in body size, and niche specialization. Using 27 venom samples and a panel of coagulation assays, we evaluated the relative coagulotoxic potency of Palearctic viper venoms and compared their neutralization by three antivenoms (Insoserp Europe, VIPERFAV and ViperaTAb) and two metalloprotease inhibitors (prinomastat and DMPS). We show that variation in morphology parallels variation in the Factor X activating procoagulant toxicity, with the three convergent evolutions of larger body sizes ( genus, genus, and uniquely within the genus) were each accompanied by a significant increase in procoagulant potency. In contrast, the two convergent evolutions of high altitude specialization (the genus and uniquely within the genus) were each accompanied by a shift away from procoagulant action, with the species being particularly potently anticoagulant. Inoserp Europe and VIPERFAV antivenoms were both effective against a broad range of species, with Inoserp able to neutralize additional species relative to VIPERFAV, reflective of its more complex antivenom immunization mixture. In contrast, ViperaTAb was extremely potent in neutralizing but, reflective of this being a monovalent antivenom, it was not effective against other species. The enzyme inhibitor prinomastat efficiently neutralized the metalloprotease-driven Factor X activation of the procoagulant venoms. In contrast, DMPS (2,3-dimercapto-1-propanesulfonic acid), which as been suggested as another potential treatment option in the absence of antivenom, DMPS failed against all venoms tested. Overall, our results highlight the evolutionary variations within Palearctic vipers and help to inform clinical management of viper envenomation.
Topics: Animals; Antivenins; Blood Coagulation; Blood Coagulation Tests; Evolution, Molecular; Humans; Immunoglobulin Fab Fragments; Matrix Metalloproteinase Inhibitors; Organic Chemicals; Snake Bites; Species Specificity; Time Factors; Unithiol; Viper Venoms; Viperidae
PubMed: 34177943
DOI: 10.3389/fimmu.2021.688802 -
Nanoscale Jul 2021A novel nanomaterial is synthesized based on the functionalization of graphene quantum dot with dimercaprol (GQD-DMC). Fourier transform infrared spectroscopy (FTIR),...
A novel nanomaterial is synthesized based on the functionalization of graphene quantum dot with dimercaprol (GQD-DMC). Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (TEM) are used to approve the successful synthesis of GQD-DMC. The synthesized nanomaterial is used as an electrode modifier for the sensitive and selective determination of mercury(ii) ions in real water samples. The method of evaluation is based on the pre-concentration of mercury ions on the GQD-DMC modified glassy carbon electrode, reduction of Hg(ii), and anodic stripping voltammetric measurement of these reduced ions in a buffer solution. The pre-concentration of mercury ions is driven by the affinity interaction between the surface containing functional groups of DMC and Hg(ii) ions. The GQD-DMC modified glassy carbon electrode (GQD-DMC/GCE) shows extra sensitivity and selectivity for mercury(ii) detection, which is assumed to be due to the increased surface area as well as the presence of sulfur-containing functional groups on the modified structure.
PubMed: 34160516
DOI: 10.1039/d1nr00076d