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Tissue engineering enables the production of three-dimensional microtissues which mimic naturally occurring conditions in special tissues. These 3D culture systems are particularly suitable for application in regenerative medicine or experimental pharmacology and toxicology. Therefore, it is important to analyse the cells in their 3D microenvironment with regard to viability and differentiation. Tetrazolium assays (WST-8 and MTS) are still the methods of choice for estimating the number of living, metabolically active cells, with WST-8 being cell-impermeable compared to MTS. In contrast to these methods, the ATP assay is an endpoint method based on the luciferase-induced reaction of ATP with luciferin after cell lysis.We compared three methodologically different proliferation/toxicity assays (MTS, WST-8, ATP) in monolayer (2D) and 3D culture systems to improve the technically challenging determination of the number of viable cells.Chondrocytes were isolated from human articular cartilage. Three different test systems (MTS, WST-8, ATP) were applied to monolayer cells (2D, varying cell numbers) and spheroids (3D, different sizes) in 96-well plates. The intracellular ATP concentration was determined by luciferase-induced reaction of ATP with luciferin using a luminometer. Formazan formation was measured spectrophotometrically after different incubation periods. Evaluation was performed by phase contrast microscopy (toxicity), correlation of cell count and ATP concentration or absorption signal (Gompertz function) and propidium iodide (PI) staining to proof the cell lysis of all cells in spheroids.In 2D culture, all three assays showed a good correlation between the number of seeded cells and the ATP concentration or absorption data, whereas the MTS-assay showed the lowest specificity. In 3D culture, the spheroid sizes were directly related to the number of cells seeded. The absorption data of the WST-8 and MTS assay correlated only for certain spheroid size ranges, whereas the MTS-assay showed again the lowest specificity. Only the measured intracellular ATP content showed a linear correlation with all spheroid sizes ranging from 100–1000 μm. The WST-8 assay revealed the second-best sensitivity which allows the measurement of spheroids larger than 240 μm. Phase contrast observation of monolayer cells showed toxic effects of MTS after 6 h incubation and no signs of toxicity of WST-8. Staining with propidium iodide showed complete lysis of all cells in a spheroid in the ATP assay.Among tetrazolium-based assays, WST-8 is preferable to MTS because of its non-toxicity and better sensitivity. When determining the number of viable cells in the 2D system, caution is advised when using the ATP assay because of its two-phase slope of the correlation graph concerning cell number and intracellular ATP. In 3D systems of human chondrocytes, the ATP-assay is superior to the other two test systems, as the correlation graph between cell number and intracellular ATP is biphasic. Since differentiation processes or other metabolic events can influence the results of proliferation and toxicity assays (determination of viable cells), this should be taken into account when using these test systems. [ABSTRACT FROM AUTHOR]

Nanotechnology, the main technology in the twenty-first century, is the perception and control of matter at the dimensions 1-100 nanometers which revolutionized many aspects of modern life. Birds have not been used as commonly animal models in experimental toxicology but have proven useful in monitoring of environmental quality. This study aimed to evaluate zinc oxide nanoparticle (nano-ZnO) toxicity on kidneys in the homing pigeons (Columba livia f. urbana). The experimental groups orally received doses of 0, 30, 50, and 75 mg kg-1 b.w. of nanoZnO (1 ml per bird, everyday) for time periods of 7 and 14 days. The lipid peroxidation (MDA/LPO) content, catalase (CAT) activity, and carbonyl protein (CP) content were increased and the total antioxidant capacity (TAC) level was lowered in kidney samples. The plasma levels of uric acid, urea, and creatinine were also slightly elevated (p>0.05). Histopathological examinations showed glomerular nanoparticle aggregation and tubular necrosis lines in the kidney parenchyma. In brief, nano-ZnO affected kidney function and structure in homing pigeons through the induction of oxidative stress. [ABSTRACT FROM AUTHOR]

Organ-on-a-chip platforms are an emerging technology in experimental and regulatory toxicology (species-specific differences, ethical considerations). They address gaps between in vivo and in vitro models. However, there are still certain limitations considering material, setup and applicability. The current study examined the suitability of a commercially available polydimethylsiloxane-based (PDMS) organ-chip for the toxicokinetic characterization of the highly toxic nerve agent VX and the organophosphate pesticide parathion. The respective concentrations of 1000 µmol/L and 100 µmol/L VX and parathion were chosen deliberately high in order to study concentrations even if high compound absorption by PDMS might occur. Neuronal and liver spheroids, totaling 2 × 106 cells were used to study concentration changes of VX and parathion. In addition, VX enantiomers were quantified. The current study suggests a significant absorption of VX, respectively parathion by PDMS. This might require future investigation of alternative materials or coatings to limit absorption for organophosphorus compounds in toxicokinetic studies. • A polydimethylsiloxane-based (PDMS) organ-on-a-chip model was investigated. • The absorption of organophosphorus compounds was studied. • High compound absorption was shown for VX and parathion. [ABSTRACT FROM AUTHOR]

Astragalus L., is the most populated plant genus on the planet. It has found use in folk medicine to treat many different forms of ailment. However, the toxicity studies of the genus and the chemicals isolated from it, are scarce and the toxicological profile is largely unknown. Caenorhabditis elegans has been used in multiple scientific disciplines. Its ease of use, genetic similarity to humans in many pathways, connectome and nervous system and resistance to environmental stress make it among the best organisms for toxicity testing. The present study used C. elegans chemotaxis responses, and micronucleus generation, to evaluate the potential neurotoxicity of some selected cycloartane-type glycosides; astragalosides IV (1) and VI (2), astrasieversianin II (3), baibutoside (4), and macrophyllosaponins B (5) and D (6), in the short- and long-term domain, along with long-term genotoxicity testing. The results indicate long-term chemotaxis inhibition by compounds 1, 2, 3 and 5, whereas only compound 3 inhibited chemotaxis in the short-term. Compound 1 was found to significantly increase micronucleus generation at the highest tested dose. The study demonstrates the usefulness of the Nematode Chemotaxis and in vivo Micronucleus Assays for the determination of the toxicity of natural products, while illuminating the points of consideration that future studies may be designed to address. [ABSTRACT FROM AUTHOR]

Featured Application: The results of this work will be used to develop a system to assist ophthalmologist doctor decisions. The electroretinography (ERG) is a diagnostic test that measures the electrical activity of the retina in response to a light stimulus. The current ERG signal analysis uses four components, namely amplitude, and the latency of a-wave and b-wave. Nowadays, the international electrophysiology community established the standard for electroretinography in 2008. However, in terms of signal analysis, there were no major changes. ERG analysis is still based on a four-component evaluation. The article describes the ERG database, including the classification of signals via the advanced analysis of electroretinograms based on wavelet scalogram processing. To implement an extended analysis of the ERG, the parameters extracted from the wavelet scalogram of the signal were obtained using digital image processing and machine learning methods. Specifically, the study focused on the preprocessing of wavelet scalogram as images, and the extraction of connected components and thier evaluation. As a machine learning method, a decision tree was selected as one that incorporated feature selection. The study results show that the proposed algorithm more accurately implements the classification of adult electroretinogram signals by 19%, and pediatric signals by 20%, in comparison with the classical features of ERG. The promising use of ERG is presented using differential diagnostics, which may also be used in preclinical toxicology and experimental modeling. The problem of developing methods for electrophysiological signals analysis in ophthalmology is associated with the complex morphological structures of electrophysiological signal components. [ABSTRACT FROM AUTHOR]

Microplastics (MPs) and nanoplastics (NPs) have become an important global environmental issue due to their widespread contamination in the environment. This review summarizes existing literature on the effects of MPs/NPs on three important biomarkers including enzymatic activity, gene expression, and histopathology in various organisms from 2016 to 2021 and suggests a path forward for future research. Application of enzymatic activity, gene expression, and histopathology biomarkers are increasingly used in experimental toxicology studies of MPs/NPs because of their early signs of environmental stress to organisms. Between 2016 to 2021, 70% of published studies focused on aquatic organisms, compared to terrestrial organisms. Zebrafish were widely used as a model organism to study adverse impacts of MPs/NPs. Polystyrene (PS) were the most important polymer used in experimental toxicology studies of MPs/NPs. Fewer studies focused on the histopathological alterations compared to studies on enzymatic activity and gene expression of different organisms exposed to MPs/NPs. There is a growing need to better understand toxic effects of environmentally relevant concentrations of MPs/NPs on enzymatic activity, gene expression, and histopathology biomarkers of both aquatic and terrestrial organisms. [ABSTRACT FROM AUTHOR]

Oxamyl is a highly toxic carbamate molecule with toxicological risk from contamination, used as an insecticide, nematicide, and acaricide on many field crops, vegetables, fruits, and ornamentals. Suspected poisoned animals and baits were collected between January 2018 and August 2021 from Lombardy and Emilia-Romagna regions and analyzed at the chemical toxicology laboratory of the Experimental Zooprophylactic Institute of Lombardy and Emilia-Romagna, located in Brescia. The analyses were carried out by an ion trap GC-MS system in 2467 suspected samples and showed the presence of oxamyl in 67 of these. In this study, we analyzed 47 (out of 67) positive baits: the provinces in which more cases have been recorded are Mantua, Ferrara, and Cremona, which overall had 72% of positivity. The nature of the analyzed samples was mostly corn (55.3%), followed by bird carcasses (19.1%), apples (14.8%), meatballs (2.1%), bread (2.1%), and other (8.5%). The use of oxamyl to produce poisoned baits is constantly increasing, proving that it must be considered as a public health risk for the possible consequences on target and non-target organisms, including humans. [ABSTRACT FROM AUTHOR]

Copyright of Revista de Toxicología is the property of Asociacion Espanola de Toxicologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Modafinil is used for the treatment of various sleep disorders; however, its usage among healthy individuals is also increasing. There are a limited number of cardiovascular side effects, including ischemic T-wave changes, dyspnea, hypertension, and tachycardia in the literature. Our research aimed to investigate the dose-dependent subacute cardiovascular effects of modafinil in rats. Thirty-two rats were randomly and equally assigned to a control group (vehicle-treated for 14 days), a subacute low-dose group (SALD, 10 mg/kg for 14 days), a subacute moderate-dose group (SAMD, 100 mg/kg for 14 days), and a subacute high-dose group (SHD, 600 mg/kg for 14 days). The cardiovascular effects of modafinil were evaluated using hemodynamic, biochemical, electrocardiographic, electrophysiologic, and histopathologic parameters. In terms of hemodynamic parameters, heart rate, and systolic/diastolic/mean blood pressure levels, electrophysiological parameters did not reach statistical significance among the groups (p > 0.05). The incidence of T-wave negativity in SAMD and SAHD groups was 25 and 37.5%, respectively. Moreover, one rat per group was affected by an atrioventricular blockage. Malondialdehyde, superoxide dismutase, catalase, and reduced glutathione levels in the heart and vascular tissues, serum troponin-I, and creatine kinase levels were similar between the modafinil-administered groups and the control group (p > 0.05); this indicates that modafinil activated neither oxidative stress nor antioxidant pathway. Also, there was no difference in histopathological parameters between groups (p > 0.05). Supratherapeutic doses of modafinil may have the potential to cause ischemic cardiac damage and atrioventricular blockage, despite inconsistency with literature findings; however, this does not pertain to hemodynamic changes. [ABSTRACT FROM AUTHOR]

The growing development and applications of nanomaterials lead to an increasing release of these materials in the environment. The adverse effects they may elicit on ecosystems or human health are not always fully characterized. Such potential toxicity must be carefully assessed with the underlying mechanisms elucidated. To that purpose, different approaches can be used. First, experimental toxicology consisting of conducting in vitro or in vivo experiments (including clinical studies) can be used to evaluate the nanomaterial hazard. It can rely on variable models (more or less complex), allowing the investigation of different biological endpoints. The respective advantages and limitations of in vitro and in vivo models are discussed as well as some issues associated with experimental nanotoxicology. Perspectives of future developments in the field are also proposed. Second, computational nanotoxicology, i.e., in silico approaches, can be used to predict nanomaterial toxicity. In this context, we describe the general principles, advantages, and limitations especially of quantitative structure–activity relationship (QSAR) models and grouping/read-across approaches. The aim of this review is to provide an overview of these different approaches based on examples and highlight their complementarity. [ABSTRACT FROM AUTHOR]

Copyright of Asian Journals of Ecotoxicology is the property of Gai Kan Bian Wei Hui and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Over the centuries, the development of knowledge about poisons and antidotes depended on their conceptualization, however, a range of poisons and the concept of antidote evolved. With the passing of time, different substances of plant, animal, and mineral origin, moreover, man-made ones, were used deliberatively, accidentally, or unintentionally as poisons. The concept of antidote was changing in line with the progress of medicine and understanding of the mechanism of how poison works. From this perspective, the history of antidotes may be considered as the quintessence of changes within toxicology. Among the theories of antidote, the most interesting is the concept of a universal one, because it has never become obsolete. This review article focuses on the changing conceptualization of antidotes. It contains an analysis of historical toxicological treatises on antidotes and PubMed articles on the same topic.

Dear Editor, Intramuscular diquat (DQ) injection (IMI) is extremely rare. This was also verified with plasma DQ concentration (5911 ng/mL) in this case, and IMI exposure would result in an earlier time-to-peak plasma DQ concentration. IMI: intramuscular injection; DQ: diquat; HP: hemoperfusion; PE: plasma exchange; CVVHDF: continuous venovenous hemodiafiltration; HD: hemodialysis. [Extracted from the article]

This study aimed at obtaining an extract enriched in phenolic compounds from the aerial parts of black wattle waste (Acacia mearnsii De Wild), characterization of its composition, and investigation of its antioxidant potential and preclinical toxicological profile. First, a phenolic compound enriched extract (PCEE) was obtained by sequential fractionation. Thereafter, the main classes of secondary metabolites present in PCEE were identified and quantified. The antioxidant, cytotoxic, and cytogenotoxic activities were evaluated using in vitro assays. Toxicological effects on locomotor function were assessed using in vivo open field and plus maze models. Cinnamic acid and coumarin were isolated from the PCEE and identified. In addition, high contents of phenolic compounds and flavonoids, responsible for the promising antioxidant activity, were quantified. The extract should a dose-dependent in vitro cytotoxicity in HaCaT cells. In the cytogenotoxicity bioassay, no differences in the mitotic index and micronuclei frequency were observed between PCEE and negative control groups. Also, there were no significant effects of the extract on the motor function. Taken together, these results show that the aerial parts of A. mearnsii can be used for obtaining bioactive compounds with the potential for promoting human and animal health. [ABSTRACT FROM AUTHOR]

The retraction has been agreed due to duplications within Figure 2 and the inclusion of figure elements in Figure 1 and 2 that were previously published [1‐4]. Thus, the conclusions of this article are considered invalid. The authors have been informed of the decision to retract but did not agree with it. References: 1. Hanaa H. Ahmeda, Wafaa Gh. Shoushab, El‐Sayed M. El‐Sayed Mahdyb, Laila A. Rashedc, Sara M. Abdob (2013), Influence of adipose tissue derived mesenchymal stem cells in combination with injectable bone substitute on osteoclastogenesis in osteoporotic rats. J Appl Pharm Sci, 3: 046‐056. https://doi.org/10.7324/JAPS.2013.3809 2. Salem, A.M., Ahmed, H.H., Atta, H.M., Ghazy, M.A. and Aglan, H.A. (2014), RETRACTED: Potential of bone marrow mesenchymal stem cells in management of Alzheimer's disease in female rats. Cell Biol Int, 38: 1367‐1383. https://doi.org/10.1002/cbin.10331 3. Ahmed H, Salem A, Atta H, Ghazy M, Aglan H. RETRACTED: Do adipose tissue‐derived mesenchymal stem cells ameliorate Parkinson's disease in rat model? Human & Experimental Toxicology. 2014;33(12):1217‐1231. doi: 10.1177/0960327114524238 4. Ahmed, H.H., Metwally, F.M., Khalil, W.K.B. et al. Bone marrow derived mesenchymal stem cells: A unique cytotherapy for rescuing degenerated dopaminergic neurons. Neurochem. J. 9, 284–294 (2015). https://doi.org/10.1134/S1819712415040029 [ABSTRACT FROM AUTHOR]

Placental alterations are responsible for adverse pregnancy outcomes like preeclampsia and intrauterine growth restriction. And yet, placenta toxicology has not become a fully-fledged toxicology field. Because placenta is very often seen only as a barrier between the mother and the fetus, there is a lack and therefore a need for an experimental human model with technical recommendations to study placenta toxicology. In vitro approaches are recommended in experimental toxicology as they focus on a specific biological process and yield high-throughput screening methods. In the present study, we first established incubation conditions to preserve signatures of the human JEG-3 cell line identity while enabling toxicity detection. JEG-3 cells prepared in our incubation conditions were renamed JEG-Tox cells. As placental alterations are mainly triggered by uncontrolled apoptosis, we second used known apoptotic agents pregnant women are exposed to, to check that JEG-Tox cells can trigger apoptosis. Ethanol, bisphenol F, quinalphos, 4,4’-DDT, benzalkonium chloride, phenoxyethanol, propylparaben, and perfluorooctanic acid all induced chromatin condensation in JEG-Tox cells. Our incubation conditions allow JEG-Tox cells to keep placental cell identity and to respond to toxic chemicals. JEG-Tox cells are a pertinent model for placenta toxicology and could be used to better understand pregnancy alterations. [ABSTRACT FROM AUTHOR]

Copyright of Revista de Toxicología is the property of Asociacion Espanola de Toxicologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background and Purpose: Resurgence in the use of chloroquine as a potential treatment for COVID‐19 has seen recent cases of fatal toxicity due to unintentional overdoses. Protocols for the management of poisoning recommend diazepam, although there are uncertainties in its pharmacology and efficacy in this context. The aim was to assess the effects of diazepam in experimental models of chloroquine cardiotoxicity. Experimental Approach In vitro experiments involved cardiac tissues isolated from rats and incubated with chloroquine alone or in combination with diazepam. In vivo models of toxicity involved chloroquine administered intravenously to pentobarbitone‐anaesthetised rats and rabbits. Randomised, controlled treatment studies in rats assessed diazepam, clonazepam and Ro5‐4864 administered: (i) prior, (ii) during and (iii) after chloroquine and the effects of diazepam: (iv) at high dose, (v) in urethane‐anaesthetised rats and (vi) co‐administered with adrenaline. Key Results: Chloroquine decreased the developed tension of left atria, prolonged the effective refractory period of atria, ventricular tissue and right papillary muscles, and caused dose‐dependent impairment of haemodynamic and electrocardiographic parameters. Cardiac arrhythmias indicated impairment of atrioventricular conduction. Studies (i), (ii) and (v) showed no differences between treatments and control. Diazepam increased heart rate in study (iv) and as with clonazepam also prolonged the QTc interval in study (iii). Combined administration of diazepam and adrenaline in study (vi) improved cardiac contractility but caused hypokalaemia. Conclusion and Implications: Neither diazepam nor other ligands for benzodiazepine binding sites protect against or attenuate chloroquine cardiotoxicity. However, diazepam may augment the effects of positive inotropes in reducing chloroquine cardiotoxicity. Linked Articles: This article is part of a themed issue on The Pharmacology of COVID‐19. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v177.21/issuetoc [ABSTRACT FROM AUTHOR]

Introduction: the metabolic syndrome is a state of chronic inflammation of low degree in which a set of metabolic alterations coexist. The increased activity of the enzyme myeloperoxidase is considered a sensitive marker of neutrophil infiltration in the inflammatory process. Objective: to determine the activity of the enzyme myeloperoxidase in the serum of Wistar rats with metabolic syndrome induced by the intake of 35% sucrose. Methods: an experimental study was carried out at the Department of Biomedical Experimental Research and the Experimental Toxicology Unit of the University of Medical Sciences of Villa Clara between September 2018 and May 2019. The universe was constituted by Wistar rats from 180 to 200g from the National Center for the Production of Laboratory Animals. We worked with a sample of two experimental groups of 10 male animals each, one subjected to a hyperglycemic diet that developed the metabolic syndrome and the other with healthy conventional food, all of them randomly formed, which were determined the myeloperoxidase in serum, as well as cholesterol, triglycerides and glycemia. Results: myeloperoxidase values in the metabolic syndrome induction group were significantly higher than the healthy one (2.57±0.33 vs 0.78±0.13). A moderate positive correlation of triacylglycerides and glycemia was observed with the activity of the myeloperoxidase enzyme. Cholesterol did not increase in the group with metabolic syndrome. Conclusions: myeloperoxidase activity is increased in animals with metabolic syndrome. [ABSTRACT FROM AUTHOR]

Copyright of Summa, Animali da Compagnia is the property of Point Veterinaire Italie s.r.l. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: Emissions from road traffic are under constant discussion since they pose a major threat to human health despite the increasingly strict emission targets and regulations. Although the new passenger car regulations have been very effective in reducing the particulate matter (PM) emissions, the aged car fleet in some EU countries remains a substantial source of PM emissions. Moreover, toxicity of PM emissions from multiple new types of bio-based fuels remain uncertain and different driving conditions such as the sub-zero running temperature has been shown to affect the emissions. Overall, the current literature and experimental knowledge on the toxicology of these PM emissions and conditions is scarce. Methods: In the present study, we show that exhaust gas PM from newly regulated passenger cars fueled by different fuels at sub-zero temperatures, induce toxicological responses in vitro. We used exhaust gas volume-based PM doses to give us better insight on the real-life exposure and included one older diesel car to estimate the effect of the new emissions regulations. Results: In cars compliant with the new regulations, gasoline (E10) displayed the highest PM concentrations and toxicological responses, while the higher ethanol blend (E85) resulted in slightly lower exhaust gas PM concentrations and notably lower toxicological responses in comparison. Engines powered by modern diesel and compressed natural gas (CNG) yielded the lowest PM concentrations and toxicological responses. Conclusions: The present study shows that toxicity of the exhaust gas PM varies depending on the fuels used. Additionally, concentration and toxicity of PM from an older diesel car were vastly higher, compared to contemporary vehicles, indicating the beneficial effects of the new emissions regulations. [ABSTRACT FROM AUTHOR]

Detection of mixture effects is a major challenge in current experimental and regulatory toxicology. Robust markers are needed that are easy to quantify and responsive to chemical stressors in a broad dose range. Several hepatic enzymes and proteins related to drug metabolism like cytochrome-P-450 (CYP) enzymes and transporters have been shown to be responsive to pesticide active substances in a broad dose range and are therefore good candidates to be used as markers for mixture toxicity. Even though they can be well quantified at the mRNA level, quantification on the protein level is challenging because most of these proteins are membrane bound. Here we report the development of mass spectrometry-based assays using triple-x-proteomics (TXP) antibodies in combination with targeted selected ion monitoring (tSIM) to quantify changes of protein levels due to exposure to mixtures of pesticide active substances. Our results indicate that changes on the protein level of CYP1A1, ABCB2, ABCC3 are in line with observations on the mRNA and enzyme activity level and are indicative of mixture effects. Therefore, the tests are promising to reveal effects by chemical mixture effects in toxicological studies in rats. [ABSTRACT FROM AUTHOR]

Access to the circulatory system is essential for continuous monitoring and long-term experimental study. One of the commonest methods for venous access is femoral vein cannulation. The aim of the presented protocol was to elaborate a surgical model for cannulation of femoral vein in rat. Temporary cannulae such as butterfly needles can be used in short-term procedures, whereas long-term monitoring required surgical implantation of a biocompatible cannula. The protocol allows direct venous access, continuous monitoring and evaluation of the tested compounds in experimental pharmacology and toxicology - the tested compounds reach the systemic circulation immediately and the dose can be accurately titrated against response. The protocol can be applied as an alternative for venous access in experimental clinical settings. [ABSTRACT FROM AUTHOR]

In toxicological bioassays, organ weight is often expressed as a ratio to body weight or another denominator to account for natural differences in animal sizes. However, the relationship of treatment-induced organ and body weight change is complicated and relative weights may accordingly confound a toxicological assessment. In addition, the statistical assessment of relative weights is challenging. The examples given in this document show that toxicological interpretation of organ weight data in relation to body weight can be vastly improved by simple bivariate scatter plotting. Conversely, plots of relative organ weight are of limited value and may lead to an incorrect interpretation of toxic effects when used in isolation. Scatter plots are useful for qualitative hazard characterization and to generate hypotheses. Bivariate summary statistics indicate effect levels and help to explore the actual correlation of organ to body weight. [ABSTRACT FROM AUTHOR]

Since the mid‐1970s, thousands of studies have evaluated the toxicity of various chemicals to aquatic organisms. Results from many of these studies have been used to develop species sensitivity distributions (SSDs) or genus sensitivity distributions (GSDs) for deriving water quality guidelines. Recently, there has been more emphasis on evaluating the toxicity of chemicals to sensitive organisms rather than the entire range of sensitivities. The SSD approach is intended to inform the derivation of guidelines for the protection of all species, not just those that were included in the SSD. The overemphasis of the more sensitive end of the SSD can contribute to a skew in the observed distribution such that the shape of the distribution is distorted from what it would be if all species could be tested, which ultimately affects the derived guideline value. The freshwater acute Cu GSD derived by the US Environmental Protection Agency (USEPA) is one that exemplifies this trend, with one‐third of the genera in the GSD belonging to only 3 taxonomic families, all of which are nearer to the sensitive end of the distribution. The stronger representation of the more sensitive families does not seem to mirror the overall abundance of species within those families in nature. This tendency toward testing sensitive organisms is not seen in the chronic Cu SSD. In the present study, Cu toxicity literature is reviewed and long‐term trends in the availability of toxicity information for species of varying sensitivity are examined. As part of the present review, the apparent bias that favors the publication of toxicity data for sensitive taxa is demonstrated, and implications for the representativeness of SSDs and their use in developing water quality guidelines are discussed. Integr Environ Assess Manag 2019;00:000–000. © 2019 SETAC Key Points: Copper toxicity data have been trending toward increasingly sensitive organisms over the last couple of decades.Daphnids, unionid mussels, and salmonids are among the families most represented in the acute species sensitivity distribution (SSD).Fitting a statistical distribution to an SSD with an overabundance of sensitive organisms can result in an effect on the water quality standard, most likely making it unnecessarily low. [ABSTRACT FROM AUTHOR]

Methyl benzoate (MB) is a plant-derived volatile organic compound with insecticidal properties, but such activity has not been evaluated against the sweetpotato whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), a major crop pest. In this study, we tested methyl benzoate control efficacy on B. tabaci infecting tomato plants in a greenhouse, specifically measuring contact and fumigant toxicity, as well as repellent activity. For direct spray applications of 0% (control), 0.1%, 0.25%, 0.5%, 1%, 2% MB onto tomato leaves infested with adults of B. tabaci (< 5-d-old), 2% MB showed the highest corrected mortality (100%) at 24 h post-treatment. For residual toxicity in which the same MB solutions were sprayed onto tomato leaves and allowed to dry for 2 h before < 5-d-old adults were released, the 2% MB also showed the highest corrected mortality (100%) at 48 h post-treatment. The lethal median concentration (LC50) for eggs, fourth-instar nymphs, and adults were 0.3%, 0.2%, and 0.2%, respectively. In pot culture experiments, 1% MB concentration was found more effective at killing nymphs and preventing adult eclosion than all other concentrations, and gave 100 percent population reduction compared with the control. MB repelled adult whiteflies and caused 96.5% fumigant toxicity within 10 h post-treatment. Repellency and anti-oviposition rates against B. tabaci had median effective doses of 0.24% and 0.16%, respectively. Our results suggest that MB has strong potential as an environmentally friendly biopesticide for control of B. tabaci but field trials and further greenhouse studies are required to establish efficacy under more natural conditions. [ABSTRACT FROM AUTHOR]