Integrative analysis in toxicological assessment of the insecticide Malathion in Allium cepa L. system

For many centuries human populations have been suffering and trying to fight with disease-bearing mosquitoes. Emerging and reemerging diseases such as Dengue, Zika, and Chikungunya affect billions of people around the world and recently has been appealing to control with chemical pesticides. Malathion (MT) is one of the main pesticides used against mosquitoes, the vectors of these diseases. This study aimed to assess cytotoxicity and mutagenicity of the malathion for the bioindicator Allium cepa L. using a multivariate and integrative approach. Moreover, an appendix table was compiled with all available literature of insecticides assessed by the Allium cepa system to support our discussion. Exposures during 48h to 0.5 mg mL-1 and 1.0 mg mL-1 MT were compared to the negative control (distilled water) and positive control (MMS solution at 10 mg L-1). The presence of chromosomal aberrations, micronuclei frequency, and mitotic index abnormalities was evaluated. Anaphase bridges were the alterations with higher incidence and presented a significantly elevated rate in the concentration of 0.5 mg mL-1, including when compared to the positive control. The integrative discriminant analysis summarizes that MT in assessed concentrations presented effects like the positive control, corroborating its potential of toxicity to DNA. Therefore, it is concluded that MT in its pure composition and in realistic concentrations used, has genotoxic potential in the biological assessment of A. cepa cells. The multivariate integrative analysis was fundamental to show a whole response of all data, providing a global view of the effect of MT on DNA.

Assessment of the Toxicity of Biocompatible Materials Supporting Bone Regeneration: Impact of the Type of Assay and Used Controls

Assessing the toxicity of new biomaterials dedicated to bone regeneration can be difficult. Many reports focus only on a single toxicity parameter, which may be insufficient for a detailed evaluation of the new material. Moreover, published data frequently do not include control cells exposed to the environment without composite or its extract. Here we present the results of two assays used in the toxicological assessment of materials’ extracts (the integrity of the cellular membrane and the mitochondrial activity/proliferation), and the influence of different types of controls used on the obtained results. Results obtained in the cellular membrane integrity assay showed a lack of toxic effects of all tested extracts, and no statistical differences between them were present. Control cells, cells incubated with chitosan extract or chitosan-bioglass extract were used as a reference in proliferation calculations to highlight the impact of controls used on the result of the experiment. The use of different baseline controls caused variability between obtained proliferation results, and influenced the outcome of statistical analysis. Our findings confirm the thesis that the type of control used in an experiment can change the final results, and it may affect the toxicological assessment of biomaterial.

Stepwise Procedure for Toxicological Assessment Based on Ratio of Mean Differences for a Normally Distributed Data

We propose a new stepwise confidence set procedure for toxicity study based on ratio of mean difference. Statistical approaches for evaluating toxicity studies that properly control familywise error rate (FWER) for difference of means between treatments and a control already exist. However, in some therapeutic areas, ratio of mean differences is desirable. Therefore, we construct stepwise confidence procedure based on Fieller's confidence intervals for multiple ratio of mean difference without multiplicity adjustment for toxicological evaluation. Simulation study revealed that the FWER is well controlled at prespecified nominal level α. Also, the power of our approach increases with increasing sample size and ratio of mean differences.

Preliminary sub-acute toxicological assessment of methanol leaves extract of Culcasia angolensis (Araceae) in Wistar rats

Background The plant Culcasia angolensis (Araceae) has diverse ethnomedicinal uses, including the management of rheumatic pain, healing of cuts, dislocations, and bruises. Despite its potential therapeutic uses, the toxicity profile of Culcasia angolensis has not been evaluated. This study assessed the sub-acute toxicity effects of Culcasia angolensis leaves extract (CAE). The phytochemical determination of the CAE was conducted as per the standard protocols. The median lethal dose (LD50) was determined using the Organization for Economic Cooperation and Development (OECD) 423 guideline. Besides, the sub-acute toxic effects of the CAE (125, 250, and 500 mg/kg) were investigated following administration of the CAE daily for 28 consecutive days as per the OECD 407 guideline. The weekly body weights were recorded. The animals were euthanized on the 29th day, and blood samples were obtained for haematological and biochemical investigations. The heart, kidney, liver, and lungs were collected for histological examinations. Besides, the relative organ weights (ROW) were determined. Results The CAE contains cardiac glycosides, alkaloids, tannins, flavonoids, steroids, saponins, and terpenoids. The oral LD50 was above 5 g/kg. There was a remarkable decline in the weekly body weight at all the CAE doses. The CAE increased the lymphocytes, aspartate transaminase, and urea. However, the levels of alanine transaminase and alkaline phosphatase were elevated remarkably. The histological studies did not reveal any serious organs abnormalities. Conclusion The CAE is relatively safe on acute administration. However, it may be slightly toxic on sub-acute administration, especially to the liver and kidney.

Choice of benthic macroinvertebrate-based metrics for assessing water quality in the littoral zone under anthropogenic disturbance in southern Lake Kivu (Central Africa)

Benthic macroinvertebrates are widely used to assess the ecological quality of fresh waters. This is because they are in direct contact with the aquatic environment and respond differently to pollutants and changes in the watershed, which are difficult to assess by toxicological or chemical monitoring alone. this study used benthic macroinvertebrate parameters to assess the quality of the nearshore waters of lake Kivu. Twenty-six metrics covering various aspects of the community were tested using whisker plots to compare their sensitivity in discriminating between reference and disturbed stations. Nine parameters (% EPT taxa, % Diptera taxa, % Chironomid taxa, % Insect taxa; % no Insects taxa, ratio EPT/Chironomid taxa, % moderate tolerant taxa, % very moderate tolerant taxa, Family Biotic Index) were found to be sensitive and were able to discriminate between reference and disturbed stations. All sensitive metrics, with the exception of the percentage of EPT taxa, were positively and/or negatively correlated with the physico-chemical parameters affected by the changes in the littoral zone. The combined values of the three calculated biotic indices (ASPT, BMWP and FBI) showed that the biological water quality varies from moderate to good in the reference stations and from average to poor in the disturbed stations. It is concluded that metrics based on benthic macroinvertebrates are effective for assessing water quality in the littoral zone of Lake Kivu in the context of the lack of historical water quality databases and specific tools for toxicological assessment. It is suggested to compare the performance of this approach with others currently used in bio-indication.

Characterization and Diversity of Microcystins Produced by Cyanobacteria from the Curonian Lagoon (SE Baltic Sea)

Microcystins (MCs) are the most widely distributed and structurally diverse cyanotoxins that can have significant health impacts on living organisms, including humans. The identification of MC variants and their quantification is very important for toxicological assessment. Within this study, we explored the diversity of MCs and their potential producers from the Curonian Lagoon. MC profiles were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) method, while the potential producers were detected based on the presence of genus-specific mcyE gene sequences. Among the numerous MCs detected, one new potential MC variant with m/z 1057 was partially characterized. Moreover, two other MCs with m/z 1075 and m/z 1068 might belong to new variants with serine (Ser), rarely detected in position one of the peptides. They might also represent MC-Y(OMe)R and MC-WR, respectively. However, the application of a low-resolution MS/MS system made the unambiguous identification of the MCs impossible. Based on this example, the problems of peptide structure identification are discussed in the work. Genetic analysis revealed that potential MCs producers include Dolichospermum/Anabaena, Microcystis spp., and Planktothrix agardhii. The diversity and temporal variations in MC profiles may indicate the presence of several chemotypes of cyanobacteria in the Curonian Lagoon.

An overview of Structured Biosensors for Metal Ions Determination

The determination of metal ions is important for nutritional and toxicological assessment. Atomic spectrometric techniques are highly efficient for the determination of these species, but the high costs of acquisition and maintenance hinder the application of these techniques. Inexpensive alternatives for metallic element determination are based on dedicated biosensors. These devices mimic biological systems and convert biochemical processes into physical outputs and can be used for the sensitive and selective determination of chemical species such as cations. In this work, an overview of the proposed biosensors for metal ions determination was carried out considering the last 15 years of publications. Statistical data on the applications, response mechanisms, instrumentation designs, applications of nanomaterials, and multielement analysis are herein discussed.

Toxicological assessment of Capparis spinosa L. seed’s oil

Introduction. Herbal medicines are unique therapeutic agents that represent multicomponent complexes of biologically active substances. They have low toxicity, a wide spectrum of therapeutic action with a minimum of side effects and a relatively low cost. Capparis spinosa L. has been widely used in traditional medicine for the treatment of various diseases and health conditions. Material and methods. An assessment of the toxicometric parameters of Capparis spinosa L. seed’s oil was done by a single oral and dermal exposure, the average lethal doses have been calculated for both routes, sensitivity by sex has been studied. The local irritant, skin resorptive, effect on the mucous membranes of the eyes of experimental animals was investigated. Sensitizing activity was studied according to the complex sensitization scheme. Processing of the results was carried out by the method of variation statistics. Standard errors and other indicators were calculated using the Litchfield-Wilcoxon probabilistic analysis method modified by Prozorovsky. The difference in mean values was estimated using Student’s t-test. Results. The acute toxicity of the oil was not expressed, death of animals was not observed. Average lethal dose for a single oral exposure was above 7000 mg/kg and dermal more than 3000 mg/kg. Sensitivity by sex in an acute experiment has not been established. The oil had a mild irritating effect on the mucous membranes of the eyes. It did not show skin-irritating, resorptive-toxic and sensitizing effects. Conclusion. Capparis spinosa L seed’s oil belongs to the 4th hazard class (low hazard) according to the hygienic classification and safety requirements of substances.

Particulate and drug-induced toxicity assessed in novel quadruple cell human primary hepatic disease models of steatosis and pre-fibrotic NASH

In an effort to replace, reduce and refine animal experimentation, there is an unmet need to advance current in vitro models that offer features with physiological relevance and enhanced predictivity of in vivo toxicological output. Hepatic toxicology is key following chemical, drug and nanomaterials (NMs) exposure, as the liver is vital in metabolic detoxification of chemicals as well as being a major site of xenobiotic accumulation (i.e., low solubility particulates). With the ever-increasing production of NMs, there is a necessity to evaluate the probability of consequential adverse effects, not only in health but also in clinically asymptomatic liver, as part of risk stratification strategies. In this study, two unique disease initiation and maintenance protocols were developed and utilised to mimic steatosis and pre-fibrotic NASH in scaffold-free 3D liver microtissues (MT) composed of primary human hepatocytes, hepatic stellate cells, Kupffer cells and sinusoidal endothelial cells. The characterized diseased MT were utilized for the toxicological assessment of a panel of xenobiotics. Highlights from the study included: 1. Clear experimental evidence for the pre-existing liver disease is important in the augmentation of xenobiotic-induced hepatotoxicity and 2. NMs are able to activate stellate cells. The data demonstrated that pre-existing disease is vital in the intensification of xenobiotic-induced liver damage. Therefore, it is imperative that all stages of the wide spectrum of liver disease are incorporated in risk assessment strategies. This is of significant consequence, as a substantial number of the general population suffer from sub-clinical liver injury without any apparent or diagnosed manifestations.