Evaluating the relative potency and mechanism of action of azoles in the rat Whole Embryo Culture
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ABSTRACT:
ORGANISM(S): Rattus norvegicus
PROVIDER: GSE102082 | GEO | 2017/10/04
SECONDARY ACCESSION(S): PRJNA396549
REPOSITORIES: GEO
Similar Datasets
Project description:Relative potency plays an important role in toxicology. Estimates of relative potency are used to rank chemicals by their effects, to calculate equivalent doses of test chemicals compared to a standard, and to weight contributions of constituent chemicals when evaluating mixtures. Typically relative potency is characterized by a constant dilution factor, even when non-similar dose-response curves indicate that constancy is inappropriate. Improperly regarding relative potency as constant may distort conclusions and potentially mislead investigators or policymakers. We consider a more general approach that allows relative potency to vary as a function of dose, response, or response quantile. Distinct functions can be defined, each generalizing different but equivalent descriptions of constant relative potency. When two chemicals have identical response limits, these functions all carry fundamentally equivalent information; otherwise, relative potency as a function of response quantile is distinct and embodies a modified definition of relative potency. Which definition is preferable depends on whether one views any differences in response limits as intrinsic to the chemicals or as extrinsic, arising from idiosyncrasies of data sources. We illustrate these ideas with constructed examples and real data. Relative potency functions offer a unified and principled description of relative potency for non-similar dose-response curves.
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Project description:Transcranial Magnetic Stimulation (TMS) is a noninvasive technique that uses pulsed magnetic fields to affect the physiology of the brain and central nervous system. Repetitive TMS (rTMS) has been used in the study and treatment of neurological conditions including major depression, stroke, epilepsy, schizophrenia, multiple sclerosis, Parkinson’s, and Alzheimer’s disease, as well as other, non-neurological disorders. Among the effects of rTMS, low-frequency protocols (≤ 1Hz) are generally understood to result in cortical inhibition, whereas high-frequency protocols (≥ 3Hz) increase cortical excitability. However, the complex molecular basis of rTMS is largely unexplored. Using three complementary rat models, in vitro, ex vivo, and in vivo, we show complex patterns of hippocampal and neocortical transcriptional response to stimulation in glutamatergic and GABAergic signaling pathways, as well as multiple inflammatory pathways, among others. This broad-based molecular survey helps provide a foundation to tease out the complex molecular mechanisms of the effects of rTMS.
2023-05-30 | GSE230148 | GEO
Project description:Transcranial Magnetic Stimulation (TMS) is a noninvasive technique that uses pulsed magnetic fields to affect the physiology of the brain and central nervous system. Repetitive TMS (rTMS) has been used in the study and treatment of neurological conditions including major depression, stroke, epilepsy, schizophrenia, multiple sclerosis, Parkinson’s, and Alzheimer’s disease, as well as other, non-neurological disorders. Among the effects of rTMS, low-frequency protocols (≤ 1Hz) are generally understood to result in cortical inhibition, whereas high-frequency protocols (≥ 3Hz) increase cortical excitability. However, the complex molecular basis of rTMS is largely unexplored. Using three complementary rat models, in vitro, ex vivo, and in vivo, we show complex patterns of hippocampal and neocortical transcriptional response to stimulation in glutamatergic and GABAergic signaling pathways, as well as multiple inflammatory pathways, among others. This broad-based molecular survey helps provide a foundation to tease out the complex molecular mechanisms of the effects of rTMS.
2023-05-30 | GSE230147 | GEO
Project description:Transcranial Magnetic Stimulation (TMS) is a noninvasive technique that uses pulsed magnetic fields to affect the physiology of the brain and central nervous system. Repetitive TMS (rTMS) has been used in the study and treatment of neurological conditions including major depression, stroke, epilepsy, schizophrenia, multiple sclerosis, Parkinson’s, and Alzheimer’s disease, as well as other, non-neurological disorders. Among the effects of rTMS, low-frequency protocols (≤ 1Hz) are generally understood to result in cortical inhibition, whereas high-frequency protocols (≥ 3Hz) increase cortical excitability. However, the complex molecular basis of rTMS is largely unexplored. Using three complementary rat models, in vitro, ex vivo, and in vivo, we show complex patterns of hippocampal and neocortical transcriptional response to stimulation in glutamatergic and GABAergic signaling pathways, as well as multiple inflammatory pathways, among others. This broad-based molecular survey helps provide a foundation to tease out the complex molecular mechanisms of the effects of rTMS.
2023-05-30 | GSE230149 | GEO
Project description:Although proton pump inhibitors (PPIs) are widely used, their relative potency and ideal dosing regimens remain unclear. We analyzed data from randomized clinical trials that performed pH testing in patients receiving solid-dose PPI formulations (omeprazole, esomeprazole, lansoprazole, pantoprazole, rabeprazole) for a minimum of 5 days. We used omeprazole equivalency and the surrogate biomarker, percentage time pH > 4 over a 24-hour period (pH4time), to compare PPI effectiveness for different PPIs given once, twice, or 3 times daily. We found that increasing strength of once-daily PPIs (9-64 mg omeprazole equivalents) increased pH4time linearly from approximately 10.0 to 15.6 hours; higher doses produced no further increase in pH4time. Increasing the frequency to twice-daily PPI increased pH4time linearly, from approximately 15.8 to 21.0 hours. Three-times daily PPIs performed similarly to twice-daily PPIs. The costs of PPIs varied greatly, but the cost variation was not directly related to potency. We conclude that PPIs can be used interchangeably based on potency. Using twice-daily PPIs is more effective in increasing efficacy increasing once-daily PPI dosage. Omeprazole and lansoprazole (30 mg) and 20 mg of esomeprazole rabeprazole are functionally equivalent.
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Project description:Many comparative analyses of toxicity assume that the potency of a test chemical relative to a reference chemical is constant, but employing such a restrictive assumption uncritically may generate misleading conclusions. Recent efforts to characterize non-constant relative potency rely on relative potency functions and estimate them secondarily after fitting dose-response models for the test and reference chemicals. We study an alternative approach of specifying a relative potency model a priori and estimating it directly using the dose-response data from both chemicals. We consider a power function in dose as a relative potency model and find that it keeps the two chemicals' dose-response functions within the same family of models for families typically used in toxicology. When differences in the response limits for the test and reference chemicals are attributable to the chemicals themselves, the older two-stage approach is the more convenient. When differences in response limits are attributable to other features of the experimental protocol or when response limits do not differ, the direct approach is straightforward to apply with nonlinear regression methods and simplifies calculation of simultaneous confidence bands. We illustrate the proposed approach using Hill models with dose-response data from U.S. National Toxicology Program bioassays. Though not universally applicable, this method of estimating relative potency functions directly can be profitably applied to a broad family of dose-response models commonly used in toxicology.
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Project description:The karlotoxins are a family of amphidinol-like compounds that play roles in avoiding predation and in prey capture for the toxic dinoflagellate Karlodinium veneficum. The first member of the toxin group to be reported was KmTx 1 (1), and here we report an additional five new members of this family (3-7) from the same strain. Of these additional compounds, KmTx 3 (3) differs from KmTx 1 (1) in having one less methylene group in the saturated portion of its lipophilic arm. In addition, 64-E-chloro-KmTx 3 (4) and 10-O-sulfo-KmTx 3 (5) were identified. Likewise, 65-E-chloro-KmTx 1 (6) and 10-O-sulfo-KmTx 1 (7) were also isolated. Comparison of the hemolytic activities of the newly isolated compounds to that of KmTx 1 shows that potency correlates positively with the length of the lipophilic arm and is disrupted by sulfonation of the polyol arm.
| S-EPMC2929920 | biostudies-literature
Project description:Motivated by the lack of easily implementable and generally applicable strategies to increase and assess data accuracy, we devised a novel label-free approach, termed REQUIEM, to address challenges in relative quantitation. For comparing the relative amounts of analytes in two samples, a mixture is prepared from aliquots of the samples, and the samples and the mixture are analyzed in parallel according to the intended workflow. Processing of the resulting data using the REQUIEM algorithm yields unbiased analyte fold-changes and associated statistics, allowing several types of errors to be diagnosed or eliminated. Extensive simulations and analysis of carefully prepared standard samples demonstrated the rigorous foundations of REQUIEM. We applied REQUIEM to several real-world analytical techniques and workflows, notably to tandem mass spectrometry analysis by using isomeric oligosaccharides as test analytes. We conclude that REQUIEM can reveal inaccuracies in the data that are difficult to identify by using traditional approaches.
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Project description:Environmental protection is critical to maintain ecosystem services essential for human well-being. It is important to be able to rank countries by their environmental impact so that poor performers as well as policy 'models' can be identified. We provide novel metrics of country-specific environmental impact ranks - one proportional to total resource availability per country and an absolute (total) measure of impact - that explicitly avoid incorporating confounding human health or economic indicators. Our rankings are based on natural forest loss, habitat conversion, marine captures, fertilizer use, water pollution, carbon emissions and species threat, although many other variables were excluded due to a lack of country-specific data. Of 228 countries considered, 179 (proportional) and 171 (absolute) had sufficient data for correlations. The proportional index ranked Singapore, Korea, Qatar, Kuwait, Japan, Thailand, Bahrain, Malaysia, Philippines and Netherlands as having the highest proportional environmental impact, whereas Brazil, USA, China, Indonesia, Japan, Mexico, India, Russia, Australia and Peru had the highest absolute impact (i.e., total resource use, emissions and species threatened). Proportional and absolute environmental impact ranks were correlated, with mainly Asian countries having both high proportional and absolute impact. Despite weak concordance among the drivers of environmental impact, countries often perform poorly for different reasons. We found no evidence to support the environmental Kuznets curve hypothesis of a non-linear relationship between impact and per capita wealth, although there was a weak reduction in environmental impact as per capita wealth increases. Using structural equation models to account for cross-correlation, we found that increasing wealth was the most important driver of environmental impact. Our results show that the global community not only has to encourage better environmental performance in less-developed countries, especially those in Asia, there is also a requirement to focus on the development of environmentally friendly practices in wealthier countries.
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Project description:Normalized relative abundance measurement of amines in B. fragilis P207 (NCBI accession NZ_CP114371) culture using GC-EI-MS with methoxyamine and TMS derivatization.
2023-10-04 | MSV000093030 | MassIVE