Toxicity Endpoints Research Articles

Deciphering the phenotypic, inflammatory, and endocrine disrupting impacts of e-waste plastic-associated chemicals.

As the volume of plastic waste from electrical and electronic equipment (WEEE) continues to rise, a significant portion is disposed of in the environment, with only a small fraction being recycled. Both disposal and recycling pose unknown health risks that require immediate attention. Existing knowledge of WEEE plastic toxicity is limited and mostly relies on epidemiological data and association studies, with few insights into the underlying toxicity mechanisms. Therefore, this study aimed to perform comprehensive chemical screening and mechanistic toxicological assessment of WEEE plastic-associated chemicals. Chemical analysis, utilizing suspect screening based on high-resolution mass spectrometry, along with quantitative target chemical analysis, unveiled numerous hazardous compounds including polyaromatic compounds, organophosphate flame retardants, phthalates, benzotriazoles, etc. Toxicity endpoints included perturbation of morphological phenotypes using the Cell Painting approach, inflammatory response, oxidative stress, and endocrine disruption. Results demonstrated that WEEE plastic chemicals altered the phenotypes of the cytoskeleton, endoplasmic reticulum, and mitochondria in a dose-dependent manner. In addition, WEEE chemicals induced inflammatory responses in resting macrophages and altered inflammatory responses in lipopolysaccharide-primed macrophages. Furthermore, WEEE chemicals activated the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway, indicating oxidative stress, and the aryl hydrocarbon receptor (AhR). Endocrine disruption was also observed through the activation of estrogenic receptor-α (ER-α) and the induction of anti-androgenic activity. The findings show that WEEE plastic-associated chemicals exert effects in multiple subcellular sites, via different receptors and mechanisms. Thus, an integrated approach employing both chemical and toxicological methods is essential for comprehensive assessment of the toxicity mechanisms and cumulative chemical burden of WEEE plastic-associated chemicals.

Comparative Analysis of Recurrent Neural Networks with Conjoint Fingerprints for Skin Corrosion Prediction.

Skin corrosion assessment is an essential toxicity end point that addresses safety concerns for topical dosage forms and cosmetic products. Previously, skin corrosion assessments required animal testing; however, differences in skin architecture and ethical concerns regarding animal models have fostered the advancement of alternative methods such as in silico and in vitro models. This study aimed to develop deep learning (DL) models based on recurrent neural networks (RNNs) for classifying skin corrosion of chemical compounds based on chemical language notation, molecular substructure, physicochemical properties, and a combination of these three properties called conjoint fingerprints. Simple RNN, long short-term memory, bidirectional long short-term memory (BiLSTM), gated recurrent units, and bidirectional gated recurrent units models, along with 11 molecular features, were employed to generate 55 RNN-based models. Applicability domain and permutation importance analysis were exploited for additional trustable prediction and explanation ability of the models, respectively. Our findings indicate that BiLSTM with conjoint features of MACCS keys and physicochemical descriptors is the most effective model with 84.3% accuracy, 89.8% area under the curve, and 57.6% Matthews correlation coefficient for the external test performance. Furthermore, our model accurately predicted the skin corrosion toxicity of all new and unseen compounds beyond our test set, highlighting prominent classification performance compared to existing skin corrosion models. This finding will contribute to the utilization of DL and conjoint characteristics of molecular structure to enhance the model's predictive capability for skin toxicity assessment.

Probabilistic assessment of the cumulative risk from dietary heavy metal exposure in Chongqing, China using a hazard-driven approach

Cumulative risk assessment is significant for evaluating the combined exposure to multiple substances, but its widespread acceptance and application have been limited due to the complexity of clarifying and assessing actual exposure. In this study, we conducted a cumulative risk assessment based on hazard-driven criteria to evaluate the co-exposure to elemental contaminants in the diet of the population in Chongqing Municipality. The cumulative risk was calculated and evaluated using Monte Carlo modeling and the modified Reference Point Index (mRPI) method. Neurotoxicity and nephrotoxicity were identified as the main toxic endpoints, and the final evaluation elements included were Pb, Cd, As, and Hg. The results showed that the combined mRPI values for neurotoxicity and nephrotoxicity, resulting from exposure to the four heavy metals, ranged from 0.922 to 4.835 and 1.306 to 7.031, respectively. Cd and Pb were the primary contributors to nephrotoxicity, while Pb was the main contributor to neurotoxicity. The results indicated that combined dietary exposure to Pb, Cd, As, and Hg may pose risks of neurotoxicity and nephrotoxicity, with the combined exposure likely amplifying this risk compared to exposure to individual heavy metal elements. mRPI proves to be a more suitable index for cumulative risk assessment using a hazard-driven approach compared to other indexes, as it is derived based on specific studies and endpoints.

Association of radiation-induced normal tissue toxicity with a high genetic risk for rheumatoid arthritis.

Overlapping genes are involved with rheumatoid arthritis (RA) and DNA repair pathways. Therefore, we hypothesised that patients with a high polygenic risk score (PRS) for RA will have an increased risk of radiotherapy (RT) toxicity given the involvement of DNA repair. Primary analysis was performed on 1494 prostate cancer, 483 lung cancer and 1820 breast cancer patients assessed for development of RT toxicity in the REQUITE study. Validation cohorts were available from the Radiogenomics Consortium. All patients had undergone curative-intent radiotherapy and were assessed prospectively for toxicity. Germline genomic data was available for all patients, allowing a PRS to be calculated using 101 RA risk variants. PRS was analysed as a continuous variable and with >90th percentile cut-off. Associations with acute and late standardised total average toxicity (STAT) scores and individual toxicity end-points were analysed in multivariable models with preselected adjustment variables. Increasing PRS for RA did not increase the risk of acute or late STAT in any cohort. There was an increased risk of late oesophagitis in the lung cancer cohort (coefficient 0.018, p = .01), however this was not validated (p = .79). No individual acute or late toxicity endpoints were significantly associated with PRS for the prostate or breast cohorts. No significant results were found in the validation cohorts in multivariable models. Patients with a high genetic risk for RA do not show increased levels of toxicity after radiotherapy suggesting treatment planning does not need to be modified for such patients.

Air-water exchange: Toxicities, risks and PAHs compounds in the three gorges reservoir of China.

Air-water exchange is inevitably accompanied by the transportation of contaminants between atmosphere and water, which significantly leads to the alterations of toxicity and risks. However, the resulting changes of toxicity and risk in water and air due to the cross-interfacial transport of pollutants are still unclear. In this study, the water and atmospheric samples at the Pengxi River located in the Three Gorges Reservoir (TGR), China, were collected in winter and summer seasons respectively. The contaminated water exhibited higher toxicity effects than air in multiple toxicity endpoint tests. Besides, waters collected during winter exhibited greater toxicity effects than in summer. The concentrations of ΣPAHs were 48.0-445ngL-1 in the water and 9.44-82.3ng/m3 in the air, with ΣPAHs significantly higher in winter than in summer for water samples. Notably, the 2-3 ring PAHs showed a tendency to volatilize from water to air and may increase atmospheric toxicity, whereas the 4-6 ring PAHs tend to be deposited from air to water and may heighten toxicity in the water. Correlation analysis indicated that PAHs were important toxicants in the air, posing higher incremental carcinogenic risk, particularly during winter. Thus, the changes in toxicity and risk caused by the water-air exchange of pollutants cannot be ignored. This research contributes to a deeper understanding of the changes in toxicity effects and health risks caused by the air-water exchange of pollutants. The importance of considering the toxic effects and health concerns of micropollutants in the air as important as in water is emphasized.

Ecological risk assessment of sewage sludge as soil amendment: lethal and sublethal effects in Eisenia fetida.

Sewage sludge applications as soil amendment call for a proper ecological risk assessment due to unexpected delivery of toxic chemicals and materials. Standardized acute toxicity assays have proven to provide limited information in terms of potential hazard for soil organisms. Here, sublethal endpoints as physiological and tissue alterations were proposed as suitable tools for sewage sludge ecological risk assessment. Acute toxicity assay using earthworm Eisenia fetida (OECD n.207) was performed on sewage sludge samples from two wastewater treatment plants (A and B), and mortality, body weight, body morphology, and histology of intestinal cavity were evaluated at the end of the exposure period. Sewage sludge dilutions (1:50 and 1:100) from plant B caused a low percentage of mortality (5%), while none was observed in worms exposed to plant A. However, all specimens showed external body alterations as vesicles, swellings, constrictions, and discoloration. Histological sections highlight damages to epidermis, circular and longitudinal muscles, and chloragogenic tissue regardless of sewage sludge origin. Our findings confirm that standardized end points of acute toxicity are not sensitive enough in worms exposed to sewage sludges, while sublethal endpoints as body morphology and tissue histology are thus more suitable and appropriate endpoints for assessing potential detrimental outcomes and ecological risk for soil biota.

Retraction notice to "Analysis of ZnO nanoparticle-induced changes in Oreochromis niloticus behavior as toxicity endpoint" [Sci. Total Environ. 682 (2019) 561-571

Retraction notice to "Analysis of ZnO nanoparticle-induced changes in Oreochromis niloticus behavior as toxicity endpoint" [Sci. Total Environ. 682 (2019) 561-571

Update of a database of toxicological effects of pesticides in view of performing cumulative risk assessments. Part 1: Catalogue of toxicity endpoints and data model for the collection of toxicity endpoints.

Abstract A catalogue of toxicity endpoints was developed for a consistent collection of toxicological information. The toxicity endpoints of relevance for cumulative risk assessment were organised in a table for each target organ/tissue/system (cumulative assessment group (CAG) at level 1) including information on specific toxicological effect(s) (CAG at level 2), indicators that reflect the relevance for the CAG at level 2, and descriptions/interpretations that allow an understanding of the CAG at level 2. A data model for the collection of toxicity endpoints was developed to ensure the possibility of integration of the collected data to the EFSA OpenFoodTox database, in order to extend it to non‐critical endpoints. The collection of toxicity endpoints and grouping of active substances were performed for a total of 328 active substances and 165 of their metabolites. The data model was filled in for all the OpenFoodTox columns as far as possible and essential information which could not be entered in the OpenFoodTox columns were noted in the ‘Remark column’. In total, 29 CAGs at level 1 have been evaluated for inclusion of specific toxicological effects (CAGs at level 2), whereas four CAG1 targets (gastrointestinal tract, immune system, lungs and skin) were not evaluated as the effects observed in these CAG1 targets were not considered relevant for CAGs at level 2. A number of toxicological effects considered adverse and of relevance for human risk assessment, but generally not relevant for CAGs at level 2, include mortality, clinical signs of toxicity, changes in bodyweight and body weight gain, changes in food consumption and water consumption, changes in clinical biochemistry and urinalysis parameters and changes in organ weights without histopathological changes. © National Food Institute, Technical University of Denmark, 2024

Methodological steps forward in toxicological in vitro screening of mineral wools in primary rat alveolar macrophages and normal rat mesothelial NRM2 cells.

Man-made vitreous fibers (MMVF) comprise diverse materials for thermal and acoustic insulation, including stone wool. Depending on dimension, durability, and dose, MMVF might induce adverse health effects. Therefore, early predictive in vitro (geno)toxicity screening of new MMVF is highly desired to ensure safety for exposed workers and consumers. Here, we investigated, as a starting point, critical in vitro screening determinants and pitfalls using primary rat alveolar macrophages (AM) and normal rat mesothelial cells (NRM2). A stone wool fiber (RIF56008) served as an exemplary MMVF (fibrous vs. ground to estimate impact of fiber shape) and long amosite (asbestos) as insoluble fiber reference. Materials were comprehensively characterized, and in vivo-relevant in vitro concentrations defined, based on different approaches (low to supposed overload: 0.5, 5 and 50µg/cm2). After 4-48h of incubation, certain readouts were analyzed and material uptake was investigated by light and fluorescence-coupled darkfield microscopy. DNA-strand break induction was not morphology-dependent and nearly absent in both cell types. However, NRM2 demonstrated material-, morphology- and concentration-dependent membrane damage, CINC-1 release, reduction in cell count, and induction of binucleated cells (asbestos > RIF56008 > RIF56008 ground). In contrast to NRM2, asbestos was nearly inactive in AM, with CINC-1 release solely induced by RIF56008. In conclusion, to define an MMVF-adapted, predictive in vitro (geno)toxicity screening tool, references, endpoints, and concentrations should be carefully chosen, based on in vivo relevance, and sensitivity and specificity of the chosen cell model. Next, further endpoints should be evaluated, ideally with validation by in vivo data regarding their predictivity.

Sediment contamination in two German estuaries: A biomarker-based toxicity test with the ragworm Hediste diversicolor under intermittent oxygenation

Toxicity testing is an important tool for risk assessment of sediment contamination in estuaries. However, there has been a predominant focus on fitness parameters as toxic endpoints and on crustaceans as test organisms, while effects at the sub-organismal level and on other benthic taxa have received less attention. Also, interactions between sediment contamination and natural stressors such as oxygen are often neglected in traditional toxicity tests. Here we conducted a toxicity test of sediments from the Elbe and Oder (Odra) estuaries under three weeks of continuous and intermittent oxygenation, using biomarkers in an annelid, the ragworm Hediste diversicolor. Contaminated sediments affected worm survival and some biomarkers of antioxidant defense, electrophilic stress, and energy status with response ratios of above 20%. Toxic effects were most pronounced in sediments from the upper Elbe estuary, which contained high levels of heavy metals and organic chemicals. Oxygen regimes hardly changed the sediment effects, suggesting the robustness of the biomarker-based toxicity test with ragworms.

BOP2-TE: Bayesian optimal phase 2 design for jointly monitoring efficacy and toxicity with application to dose optimization.

We propose a Bayesian optimal phase 2 design for jointly monitoring efficacy and toxicity, referred to as BOP2-TE, to improve the operating characteristics of the BOP2 design proposed by Zhou. BOP2-TE utilizes a Dirichlet-multinomial model to jointly model the distribution of toxicity and efficacy endpoints, making go/no-go decisions based on the posterior probability of toxicity and futility. In comparison to the original BOP2 and other existing designs, BOP2-TE offers the advantage of providing rigorous type I error control in cases where the treatment is toxic and futile, effective but toxic, or safe but futile, while optimizing power when the treatment is effective and safe. As a result, BOP2-TE enhances trial safety and efficacy. We also explore the incorporation of BOP2-TE into multiple-dose randomized trials for dose optimization, and consider a seamless design that integrates phase I dose finding with phase II randomized dose optimization. BOP2-TE is user-friendly, as its decision boundary can be determined prior to the trial's onset. Simulations demonstrate that BOP2-TE possesses desirable operating characteristics. We have developed a user-friendly web application as part of the BOP2 app, which is freely available at https://www.trialdesign.org.

Prediction of key toxicity endpoints of AP-238 a new psychoactive substance for clinical toxicology and forensic purposes using in silico methods

This study performed advanced toxicological assessments of the new substance AP-238 using nine ‘green’ in silico methods, focusing on acute toxicity, organ-specific effects, skin and eye irritation, genetic toxicity, and cardiotoxicity. A quantitative assessment of AP-238’s acute toxicity (AT) was performed by predicting theoretical LD50 values for both rats and mice across different administration routes using various in silico methods. Results indicated the highest toxicity via intravenous administration in mice, with a t-LD50 of 53 mg/kg, while oral administration in rats exhibited a lower toxicity range, with t-LD50 values between 666.43 and 1838.77 mg/kg, depending on the predictive model used. The identification of toxicophores (the fragment connecting the benzene ring to the piperazine ring, including the α, β, and γ carbon atoms near the nitrogen atom) in AP-238 suggests a high likelihood of lung toxicity (61%), with additional risks to the cardiovascular (58%) and renal systems (56%), emphasizing specific molecular fragments associated with these adverse effects. Genotoxic evaluations presented a mixed view, with low to moderate probabilities of a positive Ames test, suggesting some uncertainty but generally indicating a reduced risk of genetic toxicity. Eye and skin irritation risks were deemed minimal, supported by several models with high confidence. Cardiotoxicity assessments revealed varied information on the potential effects of AP-238 on the hERG channel, with some studies suggesting a nonsignificant impact, while others indicated moderate risk, although with low reliability in the predictions. This highlights the nuanced challenges in assessing the safety of novel substances through ‘green’ in silico methods.

Considerations and derivations of permitted daily exposure limits for impurities from intravitreal pharmaceutical products

Intravitreal (IVT) injection is an uncommon route of parenteral administration for therapeutic medications, but one of the most important for the treatment of ocular diseases, especially those related to macular degeneration. Nonetheless, there are currently no regulatory guidelines that specifically address how to establish a permitted daily exposure (PDE) for impurities and residual process reagents in IVT pharmaceutical drug products given the unique vulnerability of ocular tissues. The establishment of PDEs for IVT administration is complicated by the limited understanding of metabolism and clearance of small molecular weight chemicals from the human vitreous humor (VH), a problem compounded by the limited IVT-specific toxicological data. In this paper, we describe a feasible and comprehensive methodology for deriving PDE limits for impurities and residual process reagents from IVT drug products, as exemplified by five case studies, including inorganic elements, formic acid, polyethylene glycols, acetic acid, and caprolactam. The five case studies were selected to cover compounds with a wide range of impurity sources and toxicological data availability. The proposed framework considers both local ocular and systemic toxicity endpoints and advances the goal of a harmonized, science-based approach for deriving IVT PDE limits.

Recent Advances in Omics, Computational Models, and Advanced Screening Methods for Drug Safety and Efficacy.

It is imperative to comprehend the mechanisms that underlie drug toxicity in order to enhance the efficacy and safety of novel therapeutic agents. The capacity to identify molecular pathways that contribute to drug-induced toxicity has been significantly enhanced by recent developments in omics technologies, such as transcriptomics, proteomics, and metabolomics. This has enabled the early identification of potential adverse effects. These insights are further enhanced by computational tools, including quantitative structure-activity relationship (QSAR) analyses and machine learning models, which accurately predict toxicity endpoints. Additionally, technologies such as physiologically based pharmacokinetic (PBPK) modeling and micro-physiological systems (MPS) provide more precise preclinical-to-clinical translation, thereby improving drug safety assessments. This review emphasizes the synergy between sophisticated screening technologies, in silico modeling, and omics data, emphasizing their roles in reducing late-stage drug development failures. Challenges persist in the integration of a variety of data types and the interpretation of intricate biological interactions, despite the progress that has been made. The development of standardized methodologies that further enhance predictive toxicology is contingent upon the ongoing collaboration between researchers, clinicians, and regulatory bodies. This collaboration ensures the development of therapeutic pharmaceuticals that are more effective and safer.

A metabolomic analysis on the toxicological effects of the universal solvent, dimethyl sulfoxide

Dimethyl sulfoxide (DMSO) is a solvent used to dissolve a variety of organic compounds. It is presumed to be non-toxic at concentrations below 1 % v/v, although several studies have demonstrated that low dose DMSO exposure can alter cellular biochemistry. This study evaluated the toxicity of DMSO at 0.0002 % v/v to the Sydney Rock oyster, Saccostrea glomerata, following 7d of exposure. Metabolites were chosen as the toxicity endpoints because they can be used as energy sources and counteract contaminant-induced stress. Relative to seawater controls, exposure to DMSO caused a 74 % significant change in metabolites in the female digestive gland, including decreases in most amino acids, carbohydrates, nicotinamides, and lipids. The female gonad showed a 43 % significant change in metabolites, with decreases in amino acids and carbohydrates, but increases in lipids. The male digestive gland showed a 29 % significant change in metabolites, with increases in lipids. The decline in metabolites in the female digestive gland, but not in the male digestive gland, may be due to their differential metabolic demands. Furthermore, pathway impact analysis revealed that DMSO exposure altered energy metabolism, disturbed osmotic balance, and induced oxidative stress in oysters. Because the effects of DMSO are not uniform across gender and tissue, use of DMSO as a solvent will confound metabolomic experimental results when comparisons among sexes and/or tissues are integral to the experimental design. There is a risk of incomplete dissolution of contaminants unless carrier solvents are used. Therefore, in practice, a solvent control along with a water control is recommended for experimentation.

RIFM fragrance ingredient safety assessment, 4-(4-methyl-3-penten-1-yl)-2(5H)-furanone, CAS Registry number 61315-75-1

The existing information supports the use of this material as described in this safety assessment.4-(4-Methyl-3-penten-1-yl)-2(5H)-furanone was evaluated for genotoxicity, repeated dose toxicity, reproductive toxicity, local respiratory toxicity, photoirritation/photoallergenicity, skin sensitization, and environmental safety. Data show that 4-(4-methyl-3-penten-1-yl)-2(5H)-furanone is not mutagenic. The clastogenicity endpoint was evaluated using the Threshold of Toxicological Concern (TTC) for the genotoxicity endpoint material, and the exposure to 4-(4-methyl-3-penten-1-yl)-2(5H)-furanone is below the TTC (0.0025 μg/kg/day). The repeated dose, reproductive, and local respiratory toxicity endpoints were evaluated using the TTC for a Cramer Class III material, and the exposure to 4-(4-methyl-3-penten-1-yl)-2(5H)-furanone is below the TTC (0.0015 mg/kg/day, 0.0015 mg/kg/day, and 0.47 mg/day, respectively). The skin sensitization endpoint was completed using the Dermal Sensitization Threshold (DST) for reactive materials (64 μg/cm2); exposure is below the DST. The photoirritation/photoallergenicity endpoints were evaluated based on ultraviolet/visible (UV/Vis) spectra; 4-(4-methyl-3-penten-1-yl)-2(5H)-furanone is not expected to be photoirritating/photoallergenic. The environmental endpoints were evaluated; for the hazard assessment based on the screening data, 4-(4-methyl-3-penten-1-yl)-2(5H)-furanone is not Persistent, Bioaccumulative, and Toxic (PBT) as per the International Fragrance Association (IFRA) Environmental Standards. For the risk assessment, 4-(4-methyl-3-penten-1-yl)-2(5H)-furanone was not able to be risk screened as there were no reported volumes of use (VoU) for either North America or Europe in the 2019 IFRA Survey.

Elucidation of molecular mechanisms involved in tadpole toxicity employing QSTR and q-RASAR approach

Tadpoles, as early developmental stages of frogs, are vital indicators of toxicity and environmental health in ecosystems exposed to harmful organic compounds from industrial and runoff sources. Evaluating each compound individually is challenging, necessitating the use of in silico methods like Quantitative Structure Toxicity-Relationship (QSTR) and Quantitative Read-Across Structure-Activity Relationship (q-RASAR). Utilizing the comprehensive US EPA's ECOTOX database, which includes acute LC50 toxicity and chronic endpoints, we extracted crucial data such as study types, exposure routes, and chemical categories. Regression-based QSTR and q-RASAR models were developed from this dataset, emphasizing key chemical descriptors. Lipophilicity and unsaturation were significant for predicting acute toxicity, while electrophilicity, nucleophilicity, and molecular branching were crucial for chronic toxicity predictions. Additionally, q-RASAR models integrated with the "intelligent consensus" algorithm were employed to enhance predictive accuracy. The performance of these models was rigorously compared across various approaches. These refined models not only predict the toxicity of untested compounds but also reveal underlying structural influences. Validation through comparison with existing literature affirmed the relevance and robustness of our approach in ecotoxicology.

Neoadjuvant Radiotherapy and Endocrine Therapy for Oestrogen Receptor Positive Breast Cancers: The Neo-RT Feasibility Study

AimsTo establish the safety and feasibility of delivering neoadjuvant radiotherapy and endocrine therapy for oestrogen receptor-positive breast cancers with palpable size 20mm or greater, for which radiotherapy might facilitate more conservative surgery. Materials and methodsA single-arm feasibility study was conducted. Patients received whole breast radiotherapy with or without radiotherapy to nodal areas. Dose/fractionation was 40Gy in 15 fractions over 3 weeks, with or without either a simultaneous integrated boost to 48Gy or sequential boost to the tumour bed. This was followed by endocrine treatment for 20 weeks, then surgery. The primary endpoint of the study was the proportion of patients successfully completing neoadjuvant radiotherapy and endocrine treatment followed by breast surgery. Response and toxicity endpoints including mastectomy rate, peri/postoperative complications, and pathological response were also evaluated.The primary analysis is descriptive. The study regimen would be considered feasible if more than 70% of patients completed treatment, while it might not be considered feasible if less than 50% did so. With a one-sided 5% significance level and 80% power, a maximum of 43 patients would be required to detect a rate of ≤50% vs ≥70%. Results14 patients were recruited out of the planned 43. Due to slow recruitment, particularly during the COVID-19 pandemic, the decision was made to stop the trial in October 2021. One registered patient was found to be ineligible before starting treatment. 13/13 patients (100%, 90% CI: 75.3%, 100%) who received any trial treatment successfully completed all trial treatments. The lower bound of the Clopper-Pearson (exact) 90% confidence interval was 79%, indicating that the primary endpoint would have been met if the planned recruitment had been achieved. 3/13 patients underwent mastectomy. 7/13 had more conservative surgery than had been planned at baseline. 4/13 patients experienced any peri/postoperative complication. The only acute radiotherapy toxicities reported were grade 1/2 dermatitis and grade 1 fatigue. Long-term breast outcomes were clinician assessed as none/mild at all timepoints in 12/13 patients. All tumours showed evidence of some pathological response to treatment, but none had a pathological complete response. ConclusionThis treatment schedule is likely feasible. It is difficult to draw strong conclusions on safety/toxicity given the small numbers, but these seem in keeping with other recent reports of neoadjuvant breast radiotherapy.

Design and synthesis of a novel pyrazole-based molecule with potential anticancer and antimicrobial effects: A multifaceted in silico approach

Although cancer remains the largest cause of morbidity and mortality globally, there is growing concern about the usage of cancer drugs due to their serious side effects. Therefore, a compound, 3,5-di(1H-indol-6-yl)-4,5-dihydro-1H-pyrazole-1-carboxamide, was synthesized using a mixture of (E)-1, 3-Di(1H-indol-3-yl) prop-2-en-1-one, semicarbazide hydrochloride, and sodium acetate. It was then examined for its anticancer and antimicrobial properties using molecular docking, molecular dynamic simulations and molecular mechanics, and generalised born surface area (MM/GBSA). The molecular docking was performed by targeting the cancer and antimicrobial associated proteins, namely protein tyrosine phosphatase L1 (1WCH), tankyrase-1 (5ETY), and phosphotransferase enzyme family protein (6SUI). Eventually, 3,5-di(1H-indol-6-yl)-4,5-dihydro-1H-pyrazole-1-carboxamide was found to be the most promising drug candidate for fighting both cancer and microbial infections. With docking scores of -9.730 Kcal/mol for 1WCH, -9.142 Kcal/mol for 5ETY, and -7.026 Kcal/mol for 6SUI, it showed strong interactions with all the target proteins. To investigate the binding stability of 3,5-di(1H-indol-6-yl)-4,5-dihydro-1H-pyrazole-1-carboxamide with the target molecules, molecular dynamics simulations were performed for 100 ns on the docked complexes. With an RMSD of <2.8 Å, the synthesized compound was highly stable with all of the targets for 100 ns. Furthermore, the evaluation of the binding free energies (MM/GBSA) of these complexes revealed that the simulated environment had no significant influence on the binding energies, implying the synthesized molecule has strong binding affinities with the target proteins. Furthermore, in the toxicity assessment, the active probability ratio for 3,5-di(1H-indol-6-yl)-4,5-dihydro-1H-pyrazole-1-carboxamide was <0.60, indicating a low probability of organ toxicity and endpoint toxicity. Based on the results, the research concludes that the synthesized novel pyrazole-based compound could be a promising candidate for the development of new therapeutic drugs for the treatment of cancer and microbial infections.

Do CYP2D6 polymorphisms affect the efficacy and toxicity of flecainide? A cohort study

Abstract Background The CYP2D6 enzyme, coded by the CYP2D6 gene, is the primary metabolic pathway for flecainide.(1,2) Over the years, studies on how different variants of this gene affect flecainide metabolism and efficacy have yielded contradictory results.(3–7) This is likely due to the fact that CYP2D6 pharmacogenetic classifications were not standardized until 2017.(8,9) Purpose To date, there has been no published study using a standardized classification to assess the efficacy and toxicity of flecainide across different CYP2D6 phenotypes; therefore, we decided to study this. Methods We conducted a cohort study with data collected through indirect methods, blinding all parties involved except the statistician. We identified patients with flecainide prescriptions (100 mg/12 h) and follow-up in our health area (n=450,136 people) between 2017 and 2021. A primary combined endpoint composed of initial inefficacy and early toxicity was pre-set, and a secondary combined endpoint of toxicity or inefficacy during follow-up. Results 104 patients met the criteria and agreed to participate: 38 (36.5%) intermediate metabolizers, 52 (50%) normal metabolizers, 2 (1.9%) could not be classified with certainty (compatible with intermediate or normal metabolizers), 7 (6.7%) poor metabolizers, 4 (3.8%) ultra-rapid metabolizers, and 1 (1%) possible hybrid. Intermediate and normal metabolizers showed an almost superimposable incidence of the primary endpoint (28,9% vs 28,8%, p=0.99), early inefficacy (21,6% vs 17,4%, p=0.97) and early toxicity (13,2% vs 13,3%, p=0.72). No significant differences were observed in multivariate analysis (p=0.76, picture 1) or in a combined endpoint of toxicity or inefficacy during follow-up (p=0.58, Kaplan-Meier in picture 2). Differences were seen in the primary endpoint when comparing poor metabolizers to the rest of the sample, although they did not reach statistical significance (p=0.07), likely due to the small number of patients in this group (n=7, absolute risk reduction -32%; 95% confidence interval: -41% to -23%). Conclusions Using the standardized classification for CYP2D6 pharmacogenetics, no statistically significant differences were detected between the two largest groups, intermediate and normal metabolizers. It is possible that better results are achieved in poor metabolizers. Based on these results, it is worth questioning whether, in an attempt to minimize the risk of flecainide toxicity, doses that are subtherapeutic in all groups except slow metabolizers have been used unknowingly.