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result(s) for
"Antidote"
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Andexanet Alfa for the Reversal of Factor Xa Inhibitor Activity
by
Mathur, Vandana S
,
Lu, Genmin
,
Crowther, Mark A
in
Administration, Oral
,
Aged
,
Anticoagulants
2015
The new oral anticoagulants have many advantages over warfarin, but one disadvantage is the inability to rapidly reverse their anticoagulant effects. Andexanet, a small-molecule factor Xa fragment, rapidly lowered levels of rivaroxaban and apixaban in older healthy volunteers.
The direct factor Xa inhibitors apixaban, rivaroxaban, and edoxaban are used in the prevention and treatment of thromboembolism. Indications for the use of these agents include the prevention of stroke in patients with nonvalvular atrial fibrillation, the treatment and secondary prevention of deep-vein thrombosis and pulmonary embolism, and the prevention of venous thrombosis after orthopedic surgery. In spite of the demonstrated safety and efficacy of factor Xa inhibitors, as well as their practical advantages over vitamin K antagonists such as warfarin, the lack of a specific antidote to reverse their anticoagulant effects is an important limitation. In clinical trials involving . . .
Journal Article
Pralidoxime in Acute Organophosphorus Insecticide Poisoning—A Randomised Controlled Trial
by
Mohamed, Fahim
,
Jeganathan, K.
,
Hittarage, Ariyasena
in
Acetylcholinesterase - metabolism
,
Adult
,
Antidotes - adverse effects
2009
Poisoning with organophosphorus (OP) insecticides is a major global public health problem, causing an estimated 200,000 deaths each year. Although the World Health Organization recommends use of pralidoxime, this antidote's effectiveness remains unclear. We aimed to determine whether the addition of pralidoxime chloride to atropine and supportive care offers benefit.
We performed a double-blind randomised placebo-controlled trial of pralidoxime chloride (2 g loading dose over 20 min, followed by a constant infusion of 0.5 g/h for up to 7 d) versus saline in patients with organophosphorus insecticide self-poisoning. Mortality was the primary outcome; secondary outcomes included intubation, duration of intubation, and time to death. We measured baseline markers of exposure and pharmacodynamic markers of response to aid interpretation of clinical outcomes. Two hundred thirty-five patients were randomised to receive pralidoxime (121) or saline placebo (114). Pralidoxime produced substantial and moderate red cell acetylcholinesterase reactivation in patients poisoned by diethyl and dimethyl compounds, respectively. Mortality was nonsignificantly higher in patients receiving pralidoxime: 30/121 (24.8%) receiving pralidoxime died, compared with 18/114 (15.8%) receiving placebo (adjusted hazard ratio [HR] 1.69, 95% confidence interval [CI] 0.88-3.26, p = 0.12). Incorporating the baseline amount of acetylcholinesterase already aged and plasma OP concentration into the analysis increased the HR for patients receiving pralidoxime compared to placebo, further decreasing the likelihood that pralidoxime is beneficial. The need for intubation was similar in both groups (pralidoxime 26/121 [21.5%], placebo 24/114 [21.1%], adjusted HR 1.27 [95% CI 0.71-2.29]). To reduce confounding due to ingestion of different insecticides, we further analysed patients with confirmed chlorpyrifos or dimethoate poisoning alone, finding no evidence of benefit.
Despite clear reactivation of red cell acetylcholinesterase in diethyl organophosphorus pesticide poisoned patients, we found no evidence that this regimen improves survival or reduces need for intubation in patients with organophosphorus insecticide poisoning. The reason for this failure to benefit patients was not apparent. Further studies of different dose regimens or different oximes are required.
Journal Article
An Appraisal of Antidotes’ Effectiveness: Evidence of the Use of Phyto-Antidotes and Biotechnological Advancements
by
Aruwa, Christiana Eleojo
,
Sabiu, Saheed
,
Mukaila, Yusuf Ola
in
Animals
,
antidotes
,
Antidotes - administration & dosage
2020
Poisoning is the greatest source of avoidable death in the world and can result from industrial exhausts, incessant bush burning, drug overdose, accidental toxication or snake envenomation. Since the advent of Albert Calmette’s cobra venom antidote, efforts have been geared towards antidotes development for various poisons to date. While there are resources and facilities to tackle poisoning in urban areas, rural areas and developing countries are challenged with poisoning management due to either the absence of or inadequate facilities and this has paved the way for phyto-antidotes, some of which have been scientifically validated. This review presents the scope of antidotes’ effectiveness in different experimental models and biotechnological advancements in antidote research for future applications. While pockets of evidence of the effectiveness of antidotes exist in vitro and in vivo with ample biotechnological developments, the utilization of analytic assays on existing and newly developed antidotes that have surpassed the proof of concept stage, as well as the inclusion of antidote’s short and long-term risk assessment report, will help in providing the required scientific evidence(s) prior to regulatory authorities’ approval.
Journal Article
A Synthetic Receptor as a Specific Antidote for Paraquat Poisoning
by
Zhang, Xiangjun
,
Wang, Ruibing
,
Li, Lanlan
in
Administration, Oral
,
Animal Structures - pathology
,
Animals
2019
Accidental or suicidal ingestion of the world's most widely used herbicide, paraquat (PQ), may result in rapid multi-organ failure with a 60% fatality rate due to the absence of an effective detoxification solution. Effective, specific antidotes to PQ poisoning have been highly desired.
The binding constant of PQ and a synthetic receptor, cucurbit[7]uril (CB[7]), was first determined in various pH environments. The antidotal effects of CB[7] on PQ toxicity were firstly evaluated with
cell lines. With
mice models, the pharmacokinetics and the biodistribution of PQ in major organs were determined to evaluate the influence of CB[7] on the oral bioavailability of PQ. Major organs' injuries and overall survival rates of the mice were systemically examined to evaluate the therapeutic efficacy of CB[7] on PQ poisoning.
We demonstrate that CB[7] may complex PQ strongly under various conditions and significantly reduce its toxicity
and
. Oral administration of PQ in the presence of CB[7] in a mouse model significantly decreased PQ levels in the plasma and major organs and alleviated major organs' injuries, when compared to those of mice administered with PQ alone. Further studies indicated that oral administration of CB[7] within 2 h post PQ ingestion significantly increased the survival rates and extended the survival time of the mice, in contrast to the ineffective treatment by activated charcoal, which is commonly recommended for PQ decontamination.
CB[7] may be used as a specific oral antidote for PQ poisoning by strongly binding with PQ and inhibiting its absorption in the gastrointestinal tracts.
Journal Article
A non-canonical vitamin K cycle is a potent ferroptosis suppressor
2022
Ferroptosis, a non-apoptotic form of cell death marked by iron-dependent lipid peroxidation
1
, has a key role in organ injury, degenerative disease and vulnerability of therapy-resistant cancers
2
. Although substantial progress has been made in understanding the molecular processes relevant to ferroptosis, additional cell-extrinsic and cell-intrinsic processes that determine cell sensitivity toward ferroptosis remain unknown. Here we show that the fully reduced forms of vitamin K—a group of naphthoquinones that includes menaquinone and phylloquinone
3
—confer a strong anti-ferroptotic function, in addition to the conventional function linked to blood clotting by acting as a cofactor for γ-glutamyl carboxylase. Ferroptosis suppressor protein 1 (FSP1), a NAD(P)H-ubiquinone reductase and the second mainstay of ferroptosis control after glutathione peroxidase-4
4
,
5
, was found to efficiently reduce vitamin K to its hydroquinone, a potent radical-trapping antioxidant and inhibitor of (phospho)lipid peroxidation. The FSP1-mediated reduction of vitamin K was also responsible for the antidotal effect of vitamin K against warfarin poisoning. It follows that FSP1 is the enzyme mediating warfarin-resistant vitamin K reduction in the canonical vitamin K cycle
6
. The FSP1-dependent non-canonical vitamin K cycle can act to protect cells against detrimental lipid peroxidation and ferroptosis.
Biochemical and lipidomic analyses identify an anti-ferroptotic function of vitamin K and reveal ferroptosis suppressor protein 1 (FSP1) as the enzyme mediating warfarin-resistant vitamin K reduction in the canonical vitamin K cycle.
Journal Article
Systemic Delivery of Atropine Sulfate by the MicroDose Dry-Powder Inhaler
2013
Abstract
Background:
Inhaled atropine is being developed as a systemic and pulmonary treatment for the extended recovery period after chemical weapons exposure. We performed a pharmacokinetics study comparing inhaled atropine delivery using the MicroDose Therapeutx Dry Powder Inhaler (DPIA) with intramuscular (IM) atropine delivery via auto-injector (AUTO).
Methods:
The MicroDose DPIA utilizes a novel piezoelectric system to aerosolize drug and excipient from a foil dosing blister. Subjects inhaled a 1.95-mg atropine sulfate dose from the dry powder inhaler on one study day [5 doses×0.4 mg per dose (nominal) delivered over 12 min] and received a 2-mg IM injection via the AtroPen® auto-injector on another. Pharmacokinetics, pharmacodynamic response, and safety were studied for 12 hr.
Results:
A total of 17 subjects were enrolled. All subjects completed IM dosing. One subject did not perform inhaled delivery due to a skin reaction from the IM dose. Pharmacokinetic results were as follows: area under the curve concentration, DPIA=20.1±5.8, AUTO=23.7±4.9 ng hr/mL (means±SD); maximum concentration reached, DPIA=7.7±3.5, AUTO=11.0±3.8 ng/mL; time to reach maximum concentration, DPIA=0.25±0.47, AUTO=0.19±0.23 hr. Pharmacodynamic results were as follows: maximum increase in heart rate, DPIA=18±12, AUTO=23±13 beats/min; average change in 1-sec forced expiratory volume at 30 min, DPIA=0.16±0.22 L, AUTO=0.11±0.29 L. The relative bioavailability for DPIA was 87% (based on output dose). Two subjects demonstrated allergic responses: one to the first dose (AUTO), which was mild and transient, and one to the second dose (DPIA), which was moderate in severity, required treatment with oral and intravenous (IV) diphenhydramine and IV steroids, and lasted more than 7 days.
Conclusions:
Dry powder inhalation is a highly bioavailable route for attaining rapid and consistent systemic concentrations of atropine.
Journal Article
Arsenic Toxicity: Molecular Targets and Therapeutic Agents
by
Nurchi, Valeria M.
,
Buha Djordjevic, Aleksandra
,
Aaseth, Jan
in
Animals
,
Antidotes - chemistry
,
Antidotes - pharmacology
2020
High arsenic (As) levels in food and drinking water, or under some occupational conditions, can precipitate chronic toxicity and in some cases cancer. Millions of people are exposed to unacceptable amounts of As through drinking water and food. Highly exposed individuals may develop acute, subacute, or chronic signs of poisoning, characterized by skin lesions, cardiovascular symptoms, and in some cases, multi-organ failure. Inorganic arsenite(III) and organic arsenicals with the general formula R-As2+ are bound tightly to thiol groups, particularly to vicinal dithiols such as dihydrolipoic acid (DHLA), which together with some seleno-enzymes constitute vulnerable targets for the toxic action of As. In addition, R-As2+-compounds have even higher affinity to selenol groups, e.g., in thioredoxin reductase that also possesses a thiol group vicinal to the selenol. Inhibition of this and other ROS scavenging seleno-enzymes explain the oxidative stress associated with arsenic poisoning. The development of chelating agents, such as the dithiols BAL (dimercaptopropanol), DMPS (dimercapto-propanesulfonate) and DMSA (dimercaptosuccinic acid), took advantage of the fact that As had high affinity towards vicinal dithiols. Primary prevention by reducing exposure of the millions of people exposed to unacceptable As levels should be the prioritized strategy. However, in acute and subacute and even some cases with chronic As poisonings chelation treatment with therapeutic dithiols, in particular DMPS appears promising as regards alleviation of symptoms. In acute cases, initial treatment with BAL combined with DMPS should be considered.
Journal Article
Psychomotor Recovery Following Remimazolam-induced Sedation and the Effectiveness of Flumazenil as an Antidote
2020
Remimazolam tosylate (HR-7056) is a novel ester-type benzodiazepine with ultrafast onset of effect. The compound is being developed for sedation induction and maintenance during anesthesia. It was approved for procedural anesthesia in December 2019 by the National Medical Products Administration of China. Previous studies have reported on remimazolam's effects on consciousness and cognition. Although the time to full psychomotor recovery after remimazolam-mediated sedation is critical for decisions regarding hospital discharge, relevant clinical evidence is still lacking. This study investigated the residual psychomotor effects of remimazolam and their recovery from sedating treatment in 2 simulated clinical settings: (1) single-dose administration for sedation initiation; and (2) constant rate infusion for sedation maintenance.
A single-ascending-dose, parallel-group, midazolam-controlled study and a 2-way crossover study evaluating the reversal effect of flumazenil versus placebo after a 2-h constant rate infusion were conducted with HR-7056 in 87 Chinese healthy volunteers; the studies used a double-blind, randomized trial design. A battery of psychomotor tests was administered before dosing and several times postdose over 4–6 h. Pharmacokinetic, sedation, and safety assessments were performed throughout the studies.
After bolus infusion, the Bispectral Index score decreased in a concentration-dependent manner with HR-7056, accompanied by a sharp drop of Modified Observer's Assessment of Alertness/Sedation score. The recovery of consciousness was much faster with HR-7056 than with midazolam. During the constant rate infusion, the Bispectral Index score was maintained between 40 and 60 with an average plasma remimazolam concentration of ~1000 ng/mL. Subjects' performance in saccadic and smooth pursuit eye movement, body sway, test of choice reaction time, and word recall was significantly impaired after single-dose midazolam and after constant rate infusion of remimazolam. The end-of-infusion injection of flumazenil shortened the median time to full alertness to 3.5 min and effectively reversed psychomotor and cardiovascular dysfunction.
The study results showed quicker psychomotor recovery from sedation in the remimazolam-treated group. The moderate and short-lasting residual effect of remimazolam after 2-h conscious sedation proposes a need for psychomotor assessment(s) before hospital discharge. ClinicalTrials.gov identifiers: NCT01970072 and NCT03444480.
Journal Article
Performance analysis of novel toxin-antidote CRISPR gene drive systems
by
Champer, Samuel E.
,
Clark, Andrew G.
,
Kim, Isabel K.
in
Analysis
,
Antidotes
,
Antidotes - pharmacology
2020
Background
CRISPR gene drive systems allow the rapid spread of a genetic construct throughout a population. Such systems promise novel strategies for the management of vector-borne diseases and invasive species by suppressing a target population or modifying it with a desired trait. However, current homing-type drives have two potential shortcomings. First, they can be thwarted by the rapid evolution of resistance. Second, they lack any mechanism for confinement to a specific target population. In this study, we conduct a comprehensive performance assessment of several new types of CRISPR-based gene drive systems employing toxin-antidote (TA) principles, which should be less prone to resistance and allow for the confinement of drives to a target population due to invasion frequency thresholds.
Results
The underlying principle of the proposed CRISPR toxin-antidote gene drives is to disrupt an essential target gene while also providing rescue by a recoded version of the target as part of the drive allele. Thus, drive alleles tend to remain viable, while wild-type targets are disrupted and often rendered nonviable, thereby increasing the relative frequency of the drive allele. Using individual-based simulations, we show that Toxin-Antidote Recessive Embryo (TARE) drives targeting an haplosufficient but essential gene (lethal when both copies are disrupted) can enable the design of robust, regionally confined population modification strategies with high flexibility in choosing promoters and targets. Toxin-Antidote Dominant Embryo (TADE) drives require a haplolethal target gene and a germline-restricted promoter, but they could permit faster regional population modification and even regionally confined population suppression. Toxin-Antidote Dominant Sperm (TADS) drives can be used for population modification or suppression. These drives are expected to spread rapidly and could employ a variety of promoters, but unlike TARE and TADE, they would not be regionally confined and also require highly specific target genes.
Conclusions
Overall, our results suggest that CRISPR-based TA gene drives provide promising candidates for flexible ecological engineering strategies in a variety of organisms.
Journal Article
The in silico identification of novel broad-spectrum antidotes for poisoning by organophosphate anticholinesterases
2023
Owing to their potential to cause serious adverse health effects, significant efforts have been made to develop antidotes for organophosphate (OP) anticholinesterases, such as nerve agents. To be optimally effective, antidotes must not only reactivate inhibited target enzymes, but also have the ability to cross the blood–brain barrier (BBB). Progress has been made toward brain-penetrating acetylcholinesterase reactivators through the development of a new group of substituted phenoxyalkyl pyridinium oximes. To help in the selection and prioritization of compounds for future synthesis and testing within this class of chemicals, and to identify candidate broad-spectrum molecules, an in silico framework was developed to systematically generate structures and screen them for reactivation efficacy and BBB penetration potential.
Journal Article