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Significance of the LD50-test for the toxicological evaluation of chemical substances

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Abstract

The LD50-test was developed in 1927 for the biological standardization of dangerous drugs. Then it was incorporated into the routine toxicological protocol of other classes of chemical compounds and is now part of practically all governmental guidelines which regulate toxicological testing of chemicals. For scientific, economic, and ethical reasons it is necessary to periodically reassess all toxicological test procedures, including the LD50-test. Tests which are not optimal or that have become obsolete because of new scientific knowledge, must be changed or eliminated. The review of the LD50-test shows that the precision of the procedure is dependent on the number of animals used. But even with large numbers of animals there are considerable variations of the test results, because the numerical value of the LD50 is influenced by many factors, such as animal species and strain, age and sex, diet, food deprivation prior to dosing, temperature, caging, season, experimental procedures, etc. Thus, the LD50 value cannot be regarded as a biological constant. Through standardization of the test animals and the experimental conditions the variability of the LD50 determinations can be reduced but never fully eliminated. There are several tests with which an approximate LD50 can be determined. These methods use fewer animals than the classical LD50-test, but their precision and reproducibility are sufficient for most purposes of acute toxicity testing. Through incorporation of physiological, hematological, biochemical, pathological, and histopathological investigations in the simplified test procedures with small numbers of animals, it is possible to markedly increase the informational content of the results with regard to the toxicological spectrum and the target organs of toxicity. Such studies have already replaced the LD50-test in large animals, such as dogs and monkeys. It is also desirable to replace the LD50 in rodents with such a procedure. With pharmacologically inert compounds that have no acute effects with single administration the classical LD50-test does not provide relevant toxicological results. For the prediction of the human lethal dose and for the prediction of the symptomatology of poisoning after acute overdosing in man the LD50-test is of limited usefulness. An acute toxicity test with small numbers of animals combined with comprehensive studies of physiological functions, biochemical and histopathological examinations often provides more important information for emergency physicians and poison control centers. For the selection of doses to be used in subacute and chronic toxicity experiments the LD50-test does not provide consistent and reliable results. A simple pilot experiment with few animals but repeated dosing gives more useful information. For the evaluation of special risks for the human newborn and infant the LD50-test is poorly suited. For the appraisal of pharmacokinetic behavior and bioavailability the LD50-test gives only semi-quantitative, often ambiguous information. In all cases where the acute toxicity testing is mainly concerned with the evaluation of toxicological potential of the test substances, the symptomatology following acute overdosing, and the knowledge of target organs of toxicity, the classical LD50-test should be replaced by a more comprehensive short term test that can be done with small numbers of animals. The classical LD50-test should only be permitted in those rare instances where a high precision of the LD50 determination is indispensable.

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... The observed results for the highest concentration used in the measurem (120 ng/mL) allow for the assessment of the toxicity of the tested protein fraction i logical systems. Based on the presented results, the median lethal dose (LD50) wa termined using the Behrens method [32], which is presented in Table 2. The amount of the chemical substance (statistically calculated on the basis test results) that cause death in 50% of organisms after a single dose treatment for cells is 4.5% higher than for the second tested cells. ...
... The observed results for the highest concentration used in the measurements (120 ng/mL) allow for the assessment of the toxicity of the tested protein fraction in biological systems. Based on the presented results, the median lethal dose (LD50) was determined using the Behrens method [32], which is presented in Table 2. The amount of the chemical substance (statistically calculated on the basis of the test results) that cause death in 50% of organisms after a single dose treatment for U-937 cells is 4.5% higher than for the second tested cells. ...
... Based on the results of the cell survival presented in this paper, the values of the median lethal dose (LD50 median lethal dose) for cells were calculated using Behrens' method [32] with the following assumptions: the number of cells per measurement point is constant, the absorbance determined in the XTT method is correlated with the number of live cells; moreover, if the cell is experiencing a higher dose, it has survived all lower doses; if the cell dies at a lower dose, it would die at all higher doses. Then, the percentage mortality was calculated for each dose of applied venom fraction and LD50 values were obtained from the appropriate graphs. ...
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Three-finger toxins are naturally occurring proteins in Elapidae snake venoms. Nowadays, they are gaining popularity because of their therapeutic potential. On the other hand, these proteins may cause undesirable reactions inside the body′s cells. A full assessment of the safety of Naja ashei venom components for human cell application is still unknown. The aim of the study was to determine the effect of the exogenous application of three-finger toxins on the cells of monocytes (U-937) and promyelocytes (HL-60), with particular emphasis on the modification of their membranes under the influence of various doses of 3FTx protein fraction (0–120 ng/mL). The fraction exhibiting the highest proportion of 3FTx proteins after size exclusion chromatography (SEC) separation was used in the experiments. The structural response of cell membranes was described on the basis of single-component and multi-component Langmuir monolayers that mimicked the native membranes. The results show that the mechanism of protein–lipid interactions depends on both the presence of lipid polar parts (especially zwitterionic type of lipids) and the degree of membrane saturation (the greatest-for unsaturated lipids). The biochemical indicators reflecting the tested cells (MDA, LDH, cell survival, induction of inflammation, LD50) proved the results that were obtained for the model.
... Median lethal dose (LD 50 ) was first proposed by J. W. Trevan in 1976 [1]. It is used to study acute toxicity and classify toxic substance [2]. The 95% confidence interval (95% CI, μ ± σ) is used to describe LD 50 mean [3,4]. ...
... In addition, the calculation of mKM is simple to obtain an accurately LD 50 value and standard error. However, mKM violates animal rights and increase economic pressure [2,[13][14][15]. With 3Rs principles proposed (Reduction, Replacement, Refinement) [16,17], up-and-down procedure (UDP) was advocated [14,18]. ...
... The result was calculated as follows according to the results of Table 4 and formula (1), (2). Compared with normal mice, sinomenine hydrochloride has no effect on the organ indexes (Table 5). ...
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Background Up-and-down procedure (UDP) was recommended to replace traditional acute toxicity methods. However, it was limited due to the long experimental period (20–42 days). To improve UDP, an improved UDP method (iUDP) was developed by shortening observation time between sequence dosages. The aim of this study was to test the reliability of iUDP to provide a reliable method for the acute toxicity measurement of valuable or minor amount compounds. Methods Oral median lethal dose (LD50) of nicotine, sinomenine hydrochloride and berberine hydrochloride were measured both by iUDP and modified Karber method (mKM). Results LD50 of the three alkaloids measured by iUDP with 23 mice were 32.71 ± 7.46, 453.54 ± 104.59, 2954.93 ± 794.88 mg/kg, respectively. LD50 of the three alkaloids measured by mKM with 240 mice were 22.99 ± 3.01, 456.56 ± 53.38, 2825.53 ± 1212.92 mg/kg, respectively. The average time consumed by the two methods were 22 days and 14 days respectively. Total grams of the alkaloids used by the two methods were 0.0082 and 0.0673 (nicotine), 0.114 and 1.24 (sinomenine hydrochloride), 1.9 and 12.7 (berberine hydrochloride). Conclusion iUDP could replace mKM to detect acute toxicity of substances with comparable and reliable result. And it is suitable for valuable or minor amount substances.
... However, LD 50 and LC 50 have limited usage as they cannot be directly extrapolated across species and to low doses. In fact, their application as a measure of toxicity has been criticized by many toxicologists (see Zbinden and Flury-Roversi, 1981;LeBeau, 1983 There is a large body of literature in toxicology that describes the properties and applications of each of the abovementioned measures of toxicity. In addition, the measures are not independent and many of them are interrelated. ...
... J. A. Staffa and M. A. Mehlman eds. Pathotox Publishers, Inc. Zbinden, G. and Flury-Roversi, M. (1981). Signifcance of the LD50-test for the toxicological evaluation of chemical substances. ...
... In exception of part of one study (Facury Neto et al., 2004), the comparison groups (CG) have been reported accordingly, thus configurating controlled preclinical trials. In this case, the experimental protocol used for assessing the LD50 and LD100 did not required a comparison (Lorke, 1983;Zbinden & Flury-Roversi, 1981). The CGs (sham treatments) were saline solution (Facury Neto et al., 2004), distillated water (Paula-Freire et al., 2014), standard diet (Bucciarelli et al., 2010), and aqueous surfactant solutions (Ferrari et al., 2012;Ferreira et al., 2014). ...
... Both the number of experimental groups and the number of animals per group varied widely as a function of the experimental protocols carried out for toxicity assessment. According to the information provided by the researchers, majority (60 %) of the studies followed official guidelines (Brasil, 2004;OECD/OCDE, 2001) in the investigation of the toxicity of herbal products (Bucciarelli et al., 2010;Ferrari et al., 2012;S A Ferreira et al., 2014), while others (Facury Neto et al., 2004;Paula-Freire et al., 2014) performed the experiments according to other protocols (Lorke, 1983;Zbinden & Flury-Roversi, 1981 Water consumption as well as food intake in all groups were similar. The body weight was not affected in any group. ...
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Arnica" extracts are widely used in folk medicine to treat acute and chronic inflammatory ailments. Nevertheless, their toxic effects upon systemic use are still not fully understood. Therefore, this work provides a systematic review on the safety of arnica extracts following preclinical trials covering their oral and intraperitoneal administration in animal models. Henceforth, PRISMA guideline was followed and the study protocol was registered in PROSPERO (CDR42020167112). Searches were performed in PubMed (MEDLINE), Scopus, Science Direct, Web of Science (Science Citation Index), and Health Virtual Library (BVS) databases; while SYRCLE's Risk of Bias tool and CAMARADES checklist were used to assess scientific quality. From 382 articles, five studies met eligibility criteria and underwent qualitative analysis. Data of acute toxicity was reported in all the selected articles, and the treatment time was up to 14 days. Moreover, the following species were reported: Solidago chilensis (hazard categories of 4 and 5 for i.p and v.o administration, respectively); Solidago microglossa (hazard category of 3, i.p); Lychnophora trichocarpha (hazard category of ≥ 4, i.p); and Lychnophora pinaster (hazard category of ≥ 4, v.o). The alcoholic extracts showcased greater toxic potential, which increased in a dose-dependent manner after 100 mg/Kg. Concerning organ-specific toxicity, the articles reported hepatotoxicity and nephrotoxicity following histopathological analysis. However, the safety of S. chilensis, L. pinaster, L. trichocarpha, and S. microglossa following systemic administration remains unclear due to the limited experimental quality of the included papers, as well as the lack of reported chronic toxicity, pharmacokinetics, and mutagenicity studies.
... We want to emphasize that our approach is not a conventional meta-analysis but a step to obtain a broad understanding of whether different functional/taxonomic groups show any rare response to three selected climate extremes. For this purpose, we adapted the concept of median lethal dose (LD 50 ) from toxicology, in which the LD 50 concentration of a chemical causes 50% mortality in a test population (Zbinden and Flury-Roversi, 1981). Accordingly, if a climate extreme caused 50% or more population mortality of a species, we considered this as a ''rare response.'' ...
Article
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Anthropogenic climate change is increasing the incidence of climate extremes. Consequences of climate extremes on biodiversity can be highly detrimental, yet few studies also suggest beneficial effects of climate extremes on certain organisms. To obtain a general understanding of ecological responses to climate extremes, we present a review of how 16 major taxonomic/functional groups (including microorganisms, plants, invertebrates, and vertebrates) respond during extreme drought, precipitation, and temperature. Most taxonomic/functional groups respond negatively to extreme events, whereas groups like mosses, legumes, trees, and vertebrate predators respond most negatively to climate extremes. We further highlight ecological recovery after climate extremes are challenging to predict purely based on ecological responses during or immediately after climate extremes. By accounting for the characteristics of the recovering species, resource availability, and species interactions with neighbouring competitors or facilitators, mutualists, and enemies, we outline a conceptual framework to better predict ecological recovery in terrestrial ecosystems.
... Many researchers have studied the basic toxicity of substances using simple response criteria at the individual level of biological organisation. The favoured method includes investigation of toxicity at the individual level, using survival and many sublethal endpoints (reproduction, growth, behaviour, etc.), which are then used in an effort to predict influences at the highest level of biological organization (Zbinden and Flury-Roversi, 1981;Mayer et al., 1986;Blockwell et al., 1999). ...
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The purpose of this research was to determine the effects of the organophosphorothioate pesticide diazinon, its metabolite diazinon oxon and diazinon in a commercial formulation on the freshwater amphipod Gammarus pulex. It was found that diazinon in the commercial formulation was significantly more toxic to G. pulex than diazinon oxon, which in turn was significantly more toxic than diazinon. In non-lethal ecotoxicity assays, 24 h exposure to diazinon and diazinon in the commercial formulation significantly inhibited the vertical movement of G. pulex, whereas diazinon oxon had no significant effect. Inhibition of feeding was observed, with diazinon in the commercial formulation causing the most reduction, then diazinon to a lesser extent, whereas diazinon oxon had no significant effect. Only diazinon oxon caused a significant inhibition of acetylcholinesterase (AChE) activity in vitro. However, only diazinon and diazinon in the commercial formulation caused a significant inhibition of AChE activity following in vivo exposure. The levels of small heat shock protein (sHSP) and HSP 90 in post-9,000g supernatant samples were significantly increased by exposure to diazinon and the commercial diazinon formulation. Only diazinon significantly increased the level of HSP 70 in the supernatant. In contrast, diazinon and diazinon in the commercial formulation significantly increased the level of HSP 70 in 9000g pellet samples. Only diazinon in the commercial formulation significantly increased level of HSP 90 the in pellet sample. There was no significant effect of these agents on HSP 60 levels. Western blotting analysis of 10 % gels showed increased phosphotyrosine content in 51 and 75 kDa bands and increased phosphoserine and phosphothreonine content in the 75 kDa band following exposure to diazinon and diazinon in the commercial diazinon formulation. In contrast, a 51 kDa anti-phosphoserine reactive band only showed a significant increase after exposure to diazinon and IV diazinon in the commercial diazinon. Analyses by 2D-PAGE found that a small numbers of low abundance proteins had altered levels in the 9000g supernatant sample after exposure to diazinon. However, the levels were too low to allow identification by mass spectrometry (MS). In conclusion, behavioural assays and biomarkers can be employed as useful and reliable bioindicators of environmental contamination.
... In all the cases, dose response slopes were more or less identical, which is suggestive of a common mechanism for the cause of death. The LC 50 is of great significance as biological constants in the data analysis [34,35] . ...
Article
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Piscicidal effects of several solvent extarcts (distilled water, 50% ethanol, absolute ethanol and 80% methanol) of Terminalia arjuna leaves, barks and fruits were studied against a common fresh water predatory fish, Heteropneustes fossilis under laboratory conditions in terms of Behavior and mortality of fishes after 24 h. Fishes exposed to plant extracts showed agitating movement with quick surfacing, loss of balance, mucus secretion, and finally died. The LC50 values of distilled water, 50% ethanol, absolute ethanol and 80% methanol extracts were found to be 311.726, 236.141, 183.541, 478.794 ppm for leaves, 117.894, 96.998, 38.990, 304.193 ppm for barks and 1400.033, 949.209, 555.201, 875.158 ppm for fruits, respectively. Chi-square values were found to be insignificant at P<0.05 in almost all plant extracts, indicating that observed and expected mortalities did not vary significantly in relation to doses, except 80% methanol extract of barks and absolute ethanol extract of fruits. The F-values of treatments were significant at P<0.01, except 80% methanol extract of fruits, in which F-values were insignificant in all replicates at P>0.01. Based on LC50 values, order of piscicidal activity followed the pattern, bark > leaf > fruit extracts. Order of piscicidal activity for the extracts was like absolute ethanol > 50% ethanol > distilled water > 80% methanol for leaf and bark, while for fruit extracts, trend was like absolute ethanol > 80% methanol > 50% ethanol > distilled water.
... The acute dose study provides a guideline for selecting doses for the subacute and chronic low dose study, which may be more clinically relevant (Zbinden and Flury Roversi, 1981;OECD, 2001). ...
Article
Clinopodium vulgare L. (Lamiaceae) was used in the traditional Bulgarian medicine for treatment of wounds, diabetes and gastric ulcers. In this study we aimed at safety assessment of C. vulgare lyophilized water extract (CVE) characterized by ultra high-performance liquid chromatography-Orbitrap high resolution mass spectrometry (UHPLC-HRMS). The acute and sub-acute toxicity of CVE was determined in two rodent species (mice and rats), and two routes of administration - intraperitoneal (i.p.) and oral (p.o.). LD50 (i.p.) were found to be 675 mg/kg (mice) and 500 mg/kg (rats). An acute i. p. administration resulted in central nervous system toxic effects. LD50 (p.o.) was higher than 2000 mg/kg for both species. In sub-acute oral administration, CVE did not exert any toxic effect on hematology, blood and urine biochemistry, and histomorphology in pancreas, liver, spleen and kidney. In addition, based on accurate masses, MS/MS and comparison with standards, a variety of flavonoids, caffeic acid oligomers and saponins were tentatively elucidated in CVE. Rosmarinic acid was the major compound. In conclusion, CVE did not cause hematological, biochemical and histopathological changes after oral administration and it is safe for internal use. The obtained UHPLC-HRMS profile revealed CVE as a new rich source of water soluble caffeic acid oligomers.
... The compound prior to administration to humans undergoes a series of tests mostly in rodents. If a particular dose of the compound causes deaths of 50% of the tested populations, the dose is then termed as LD 50 [44]. A higher concentration or LD 50 value indicates a less toxic compound compared with a lower concentration or a smaller LD 50 value. ...
Article
Saturated free fatty acid induced adipocyte inflammation plays a pivotal role in implementing insulin resistance and type 2 diabetes. Recent reports suggest A2A adenosine receptor (A2AAR) could be an attractive choice to counteract adipocyte inflammation and insulin resistance. Thus, an effective A2AAR agonist devoid of any toxicity is highly appealing. Here, we report that indirubin-3'-monoxime (I3M), a derivative of the bisindole alkaloid indirubin, efficiently binds and activates A2AAR which leads to the attenuation of lipid-induced adipocyte inflammation and insulin resistance. Using a combination of in-silico virtual screening of potential anti-diabetic candidates and in-vitro study on insulin resistant model of 3T3-L1 adipocytes, we determined I3M through A2AAR activation markedly prevents lipid-induced impairment of the insulin signaling pathway in adipocytes without any toxic effects. While I3M restrains lipid-induced adipocyte inflammation by inhibiting NF-kB dependent pro-inflammatory cytokines expression, it also augments cAMP mediated CREB activation and anti-inflammatory state in adipocytes. However, these attributes were compromised when cells were pretreated with the A2AAR antagonist, SCH 58261 or siRNA mediated knockdown of A2AAR. I3M therefore could be a valuable option to intervene adipocyte inflammation and thus showing promise for the management of insulin resistance and type 2 diabetes.
... However, the question remains whether this time interval can be made sufficiently small to allow for effective therapeutic intervention. The standard for making such a determination relies on the LD50, or the median lethal dosage of ricin or any other toxin in a human population [26,27]. This lethal dose is expressed as a mass fraction of toxin quantity compared to the average human body weight, and for ricin this value has been estimated to be 5-10 µg/kg [28]. ...
Article
Background: In the event of a biological warfare attack, prompt real-time detection methods are necessary to identify the presence of a pathogen well before victims begin exhibiting symptoms in order to allow sufficient time for therapeutic intervention. Current techniques for detecting the presence of biological warfare agents in high-risk environments are exclusively structure-based, relying on the identification of key structural components of specific pathogens that are already well-known and studied. These techniques provide no defense against the modern capability to synthesize new and unfamiliar pathogens of an arbitrary structure that could evade these detection mechanisms. Methods/Results: This investigation tested the prospect of using electrochemical impedance spectroscopy (EIS) to create a real-time function-based biosensor to identify any cytotoxic substance, whether known or unknown, without regard to its structure. The concept was tested by exposing A549 epithelial adenocarcinoma cells to ricin in several concentrations, ranging from 1 ng/mL to 1000 ng/mL, and observing the effect on the measured impedance of the cells. With as few as three unique trials for each concentration, a statistically significant difference was observed between the impedance data for ricin-exposed cells and that of a ricin-free control group. By comparing the change in the impedance of each sample over periods of 60 minutes and 4 hours, statistically significant detection was achieved within timeframes ranging from 65 minutes after adding 1000 ng/mL ricin to 45 hours after adding 1 ng/mL ricin. Conclusion: EIS provides a highly sensitive, real-time, and non-destructive method to identify the presence of a cytotoxin. EIS demonstrates rapid detection times that become faster as the concentration increases. Further analysis describes how the design of a potential biosensing device could be used to convert an arbitrary airborne concentration to a media concentration sufficiently large as to achieve detection within the window of time necessary for therapeutic intervention.
... This is one of the most unreliable issues in animal modeling; lethal dose, 50%, (LD50) is highly unreliable. Animals' age, sex, strain, and weight have substantial effects on the results of toxicity studies, and due to huge differences of approximately all animal models, their results are extremely unreliable [73]. In vitro studies have been recently validated to replace LD50 [74,75]. ...
Article
Preclinical investigations such as animal modeling make the basis of clinical investigations and subsequently patient care. Predictive, preventive, and personalized medicine (PPPM) not only highlights a patient-tailored approach by choosing the right medication, the right dose at the right time point but it as well essentially requires early identification, by the means of complex and state-of-the-art technologies of unmanifested pathological processes in an individual, in order to deliver targeted prevention early enough to reverse manifestation of a pathology. Such an approach can be achieved by taking into account clinical, pathological, environmental, and psychosocial characteristics of the patients or an individual who has a suboptimal health condition. Inappropriate modeling of chronic and complex disorders, in this context, may diminish the predictive potential and slow down the development of PPPM and consequently modern healthcare. Therefore, it is the common goal of PPPM and translational medicine to find the solution for the problem we present in our review. Both, translational medicine and PPPM in parallel, essentially need accurate surrogates for misleading animal models. This study was therefore undertaken to provide shreds of evidence against the validity of animal models. Limitations of current animal models and drug development strategies based on animal modeling have been systematically discussed. Finally, a variety of potential surrogates have been suggested to change the unfavorable situation in medical research and consequently in healthcare.
... New drugs and compounds require to be tested for their toxicology profile before human application. 45 In vitro cytotoxicity tests have proven to be an effective alternative for animal experiments in acute toxicity experiments as estimations are possible with high accuracy. 46 The measurement of IC 50 in NPs allows to identify the potential toxic effect related with their persistent accumulation in organs, 47 as concerns have been raised on the potential risk of using NPs in medical applications. ...
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Cancer is a major public health problem being one of the main causes of morbidity and mortality today. Recent advances in catalytic nanomedicine have offered new cancer therapies based on the administration of nanoparticles (NPs) of platinum (Pt) dispersed in catalytic mesoporous nanomaterials (titania, TiO 2) with highly selective cytotoxic properties and no adverse effects. A half maximal inhibitory concentration (IC 50) study was carried out in cancerous cell lines (HeLa, DU-145, and fibroblasts) to evaluate the cytotoxic effect of different nanomaterials [Pt/TiO 2 , TiO 2 , and Pt(acac) 2 ] synthesized by the sol−gel method at concentrations 0−1000 μg/mL. The assays showed that IC 50 values for Pt in functionalized TiO 2 (NPt) in HeLa (53.74 ± 2.95 μg/mL) and DU-145 (75.07 ± 5.48 μg/mL) were lower than those of pure TiO 2 (74.29 ± 8.95 and 82.02 ± 6.03 μg/mL, respectively). Pt(acac) 2 exhibited no cytotoxicity. Normal cells (fibroblasts) treated with NPt exhibited no significant growth inhibition, suggesting the high selectivity of the compound for cancerous cells only. TiO 2 and NPt were identified as antineoplastic compounds in vitro. Pt(acac) 2 is not recommendable because of the low cytotoxicity observed.
... The administration of the decoction did not produce a significant increase in ALP activity. In histopathology, there was old hemorrhage indicated by haemosiderin deposition throughout the entire liver and kidney tissues [76]. ...
Article
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Tridax procumbens Linn. is an widespread herbaceous weed distributed throughout India. It is commonly known as coat buttons, is also dispensed as Bhringraj, and used as Ayurvedic medicine for liver disorders and hair growth. The plant is an annual or perennial herbaceous weed, found mainly in the croplands, disturbed areas, lawn, and roadsides. Literature survey suggested that the various parts of the plant were reported to possess phytochemical compounds like alkaloids, carotenoids, flavonoids, saponins, fumaric acid, β-sitosterol, and tannins. It was richly endowed with oleanolic acid, and high content of sodium and potassium are also present. Bioactive components like luteolin, glucoluteolin, quercetin, and isoquercetin also have been reported from its flowers. Primary plant pigments such as chlorophyll and carotenoids also analyzed from leaves. So, it is well known for several potential pharmacological activities like anti-microbial, anti-oxidant, wound healing, insecticidal, hepato-protective, anti-diabetic, immune modulating, anti-cancer, anti-dysentery, anti-inflammatory, and anti-hair fall. The present review study deals with natural habitat, taxonomical, phytochemical, pharmacological and toxicological activities of Tridax procumbens. This study may be helpful for identification and preparation of a clear profile of the plant which may open new avenues in the medical field in the treatment of various diseases.
... However, LD50 is not a standard way of measuring safety as many variables such as gender, age, animal species, diet, strain, bedding, caging conditions, and ambient temperature, can affect the LD50 value. [30]. ...
Article
Background: Pulcria crispa (P. crispa) is an herbal plant traditionally used to treat common ailments. Objective: In this study, we investigated P. crispa for its phytochemical constituents, antioxidant properties and effects on biochemical and hematological parameters as well as safety in albino rats. Methods: Phytochemical analysis of ethanolic extract of P. crispa was conducted using standard procedures. In vitro 2, 2-Diphenyl-1-picrylhydrazyl (DPPH) and reducing power assay were used for the investigation of antioxidant activity of extract. Acute effects on physical and behavioral changes and mortality were monitored up to 72 h after administration of different doses of C. crispa Chronic effects on body to organ ratio, biochemical and hematological parameters were measured after administration of rats with different doses of P. crispa extract for 30 days. Results: Alkaloids, flavonoids, phenols and tannins were the most abundant constituents found in P. crispa extract, which displayed a significant antioxidant activity measured by reducing power and DPPH assays. No physical, behavioral changes and mortality were noted following the acute treatment of rats with the extract. Similarly, no significant change in body to organ weight ratio was observed after chronic treatment. Hematological parameters including RBCs, Hb, PCV, MCV, MCH and MCHC values were unaltered while W.B.C count was elevated in P.crispa administered rats compared to control. crispa extract significantly reduced glucose, urea, creatinine, cholesterol, bilirubin, AST and ALT levels, whereas, triglycerides and total protein levels were increased in response to P.crispa treatment. Conclusions: This study demonstrates that P. crispa extract is rich in bioactive compounds and possesses significant antioxidant properties. Extract was also found to be safe and had no significant adverse effects on hematological parameters and exerted beneficial effects on biochemical parameters.
... Extrapolating animal data to predict health effects may include physiological, anatomical, and metabolic differences between species (e.g., other airway dichotomy, cell type and composition, other biomodified enzymes and respiratory patterns, metabolic rate, physiological changes) [66]. It should also be sufficient to predict and manage potential adverse outcomes in humans [67][68][69][70]. ...
Article
Objective and methods: Various papers related to the application of adverse outcome pathways (AOPs) for the prevention of occupational disease were reviewed. The Internet was used as the primary tool to search for the necessary research data and information, using such online resources as Google Scholar, ScienceDirect, Scopus, NDSL, and PubMed. The key search terms were "adverse outcome pathway," "toxicology," "risk assessment," "human," "worker," "occupational safety and health," and so on. Results and conclusion: The aim of this paper is to explain the use of AOP for the understanding of chemical toxicity as a conceptual means and to predict the toxic mechanism. The tools of AOP have emerged as a forward-looking alternative to the existing chemical risk assessment paradigm. AOP is being applied to the assessment of acute toxicity and to chronic toxic chemicals in the workplace. Not only can it lead to breakthroughs in occupational and environmental cancer prevention, it is also widely used in chemical risk assessment and has led to breakthroughs in the prevention of occupational disease in the workplace.
... isolated or aggregated), time of day/night and time of year. 4 Many of these factors also apply to assessments of HLD values, and thus contribute to uncertainty concerning their accuracy. ...
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The prediction of human toxicities from animal toxicity tests is often poor, and is now discouraged and in some cases banned, especially those involving the LD 50 test. However, there is a vast number of historical LD 50 data in both public and in-house repositories that are being put to little use. This study examined the correlations between human lethality (doses and concentrations) of 36 MEIC chemicals and the median values of a large number of mouse and rat LD 50 values obtained for four different routes of administration. The best correlations were found with mouse and rat intraperitoneal LD 50 values (r ² = 0.838 and 0.810 for human lethal dose, and r ² = 0.753 and 0.785 for human lethal concentration). The results show that excellent prediction of human lethal dose and concentration can be made, for this series of chemicals at least, by using uncurated rodent LD 50 values, thus offering some reparation for the millions of rodent lives sacrificed in LD 50 testing.
... We want to emphasize that our approach is not a conventional meta-analysis but a step to obtain a broad understanding of whether different functional/taxonomic groups show any rare response to three selected climate extremes. For this purpose, we adapted the concept of median lethal dose (LD 50 ) from toxicology, in which the LD 50 concentration of a chemical causes 50% mortality in a test population (Zbinden and Flury-Roversi, 1981). Accordingly, if a climate extreme caused 50% or more population mortality of a species, we considered this as a ''rare response.'' ...
... Ultimately, studies prior to genetics or epigenetics are used to assess occupational health, and the development of occupational exposure levels (OELs) should affect occupational exposure and the onset of toxicity (Gallo et al. 2011). Computational biology and the use of toxic pathways will increasingly focus on consistent physiological changes between groups of similar toxic chemicals (Jennings 2013;MacKay et al. 2013), the development of non-animal assays could provide more predictable tools or other in vivo observations using pathway-based machine information (BéruBé 2013), and should be sufficient to predict and manage potential human side effects (Chapman et al. 2010;Seidle et al. 2010;Zbinden and Flury-Roversi 1981). As a method to be applied directly to the semiconductor manufacturing process, constant monitoring of the and it is also necessary to construct a web-based system, such as AOP-KB, in the workplace of the future, so that the web-based AOP system can be used efficiently. ...
Article
Background To solve current issues using big data, solve current issues related to the semiconductor and electronics industry, I tried to establish the data for each toxicity mechanism for adverse outcome pathway (AOP) for the exposure.ObjectiveI planned to increase the efficiency of human hazard assessment by searching, analyzing, and linking test data on the relationship between key events occurred at each level, which are the biological targets of chemicals in semiconductor manufacturing.ResultsIt was found that 48 kinds of chemicals had 11 AOPs, while 103 chemicals had multiple AOPs, and 26 had case evidence. As a result of AOP analysis, it was found that a total of 320 chemicals had 42 AOPs, and 190 major chemicals corresponded to 11 AOPs. It was found necessary to develop a complex AOP and secure an (inhalation or dermal) exposure scenario for combined exposure at work. As a comparative search (41 out of 190 chemicals) of biomarkers specific to occupational diseases, 12 biomarkers were found to be related to breast cancer. The AOPs for 50 specific chemicals were presented, together with occupational disease-specific AOPs and key events relationship from 50 chemicals, and taxonomic classification for each AOP analysis could be found. With a comparative search, 41 out of 190 chemicals were associated with specific biomarkers for occupational diseases, and 12 mRNA or protein biomarkers were found to be related to breast cancer by cross-validation with the attached Table 24 of the Enforcement Regulations of the OSHAct and the CTD.Conclusion The mechanism of occupational diseases caused by chemicals was presented, together with pathological preventions. I believe that a strategy is needed to expand the target organization for each chemical by linking with activities, such as work environment measurement, and cooperating with screening items and methods suitable for toxic chemicals, like AOP tools.
... 3.6.1. Acute toxicity study and determination of LD 50 An estimation of the lethal dose, which is expected to cause 50% death of test animals observed over a specified period, is required to specify the acute toxicity endpoints or safety of any synthesized chemicals [65]. Chemicals with higher LD 50 values are regarded as safer for biological systems than those with lower LD 50 values [66]. ...
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The prescribed use of non-steroidal anti-inflammatory drugs is associated with numerous life-threatening side effects. There is a great need to develop low-dose NSAID formulations to prevent the rate of adverse events while retaining the therapeutic efficacy. In this context, we prepared nanoformulated naproxen using MgO as a nanocarrier and PVA as coating agent and investigated its biological activity in comparison to free form naproxen sodium (NPRS) and standard anti-inflammatory drugs. MgO nanoparticles with a hydrodynamic size of approximately 140–484 nm were prepared and conjugated with NPRS and capped with hydrophilic polymer (PVA) successfully. Conjugation of NPRS with MgO nanoparticles was confirmed by UV–Visible, FTIR, XRD, DLS, LIBS techniques. The hydrodynamic size and surface charge of nanoformulated naproxen were found to be 161 nm and −8.85 mV, respectively. Nanoformulated naproxen showed maximal and sustained release (>95%) at pH 6.8 within 24 h. Investigation of thermal attributes showed that the nanoformulated naproxen was more stable at a higher temperature than free NPRS. In vivo anti-inflammatory, analgesic, and antipyretic activities of nanoformulated naproxen revealed that in all cases, the potency and efficacy of nanoformulated naproxen were found to be higher than NPRS. Moreover, nanoformulated naproxen was well tolerated up to 2000 mg/kg b.w with an LD50 of 2574.77 mg/kg. The ratio between the minimum effective dose (1 mg/kg) and LD50 indicated a broader therapeutic window. Since the concentration of NPRS in nanoformulated naproxen was only 43.2 ± 2%, our results indicated that conjugation to MgO nanocarrier boosts the biological activity of NPRS by approximately 2.3 times. In addition, nanoformulated naproxen is found to be biocompatible and hemocompatible. We conclude that the nanosizing of a drug offer much promise as a better alternative to standard anti-inflammatory drugs for the treatment of various diseases.
... Therefore, conducting toxicity studies are clinically important since they provide significant health-related information, such as, dose-response curve, safety assessment of new chemicals, venoms, antivenoms, drugs or food additives, and useful data for epidemiological studies [30,43]. Although, LD50 tests have their limitations and disadvantages, such as using large number of animals, causing considerable pain in them, and the confounding factors, e.g., species differences in gender, age, diet, genetic strain, health, degree of starvation, and method of dosing [44,45], they are still being used. ...
Article
Background: Poisoning due to the bites and stings of venomous snakes and scorpions is a neglected public health problem, particularly in rural areas. Poor health facilities and inadequate knowledge of health care personnel are the major factors that result in envenomated human victims not receiving adequate care and medical attention. There is a great need for up-to-date and effective healthcare knowledge and awareness of the potency and lethality of venomous creatures in Iran. Assessment of the potency, acute toxicity, and lethal effects of venomous creatures come from a variety of specific tests, such as the 50% median lethal dose (LD50) and ample animal experimentations. Methods: In the present study, using modified Reed-Muench method, the LD0, LD50, and LD100 values of the venoms from five Iranian vipers and one scorpion were determined. The studied venomous creatures were: Macrovipera lebetina, Vipera albicornuta, Vipera raddei, Caucasicus intemedius agkistrodon, Montivipera latifii, and one scorpion Hemiscorpius lepturus. The venoms were injected in Albino mice (n=204) intraperitoneally, and their toxicities determined. Results: The results revealed that the LD50 values of the above-mentioned creatures were 3.87, 2.05, 1.63, 1.45, 0.84, and 6.33 mg/kg, respectively. Among the vipers, M. latifii had the most potent venom while M. lebetina’s venom had the lowest toxicity. Conclusion: Theoretically, the determined LD50 values provide for objective comparisons of the toxicity among of the venoms. However, comparison becomes complicated due to variations in the venoms’ LD50. Further, based on the venoms’ toxicity levels, H. lepturus’ venom caused the lowest toxicity in the Albino mice.
... Besides, the presentation of the observational data and the results of related statistical tests comparing the effects of different treatment doses to control is often lacking. While LD 50 (with or without associated uncertainty) values are usually reported, their numerical value can be greatly influenced by factors such as the number, age or diet of animals tested, food deprivation prior to dosing, housing, or other experimental conditions; therefore, they should not be regarded as biological constants (Zbinden and Flury-Roversi 1981). Nevertheless, findings so far generally implied that present field-realistic concentrations of this neonicotinoid have a minor acute and chronic effect on bumblebee mortality irrespective of the form of application (i.e. ...
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Due to recent changes in regulation, acetamiprid has become the only neonicotinoid that can be applied without restrictions and in open field cultivations in the EU from 2021. We provide an overview of the current knowledge on the effects of this insecticide on bumblebees and assessed whether available empirical evidence supports the claim that acetamiprid poses negligible risk to these pollinators. We found that there is limited data on the lethal and sublethal effects of this pesticide on bumblebees. While risk assessment results suggest that field-realistic concentrations of acetamiprid have minor acute and chronic toxicity, detrimental sublethal effects, including reduced reproductive output, have been observed when bumblebees were exposed to high doses of this insecticide. We propose that further research on the topic is warranted as the more extensive application of acetamiprid may lead to such high concentrations in the field.
... New drugs and compounds require to be tested for their toxicology profile before human application. 45 In vitro cytotoxicity tests have proven to be an effective alternative for animal experiments in acute toxicity experiments as estimations are possible with high accuracy. 46 The measurement of IC 50 in NPs allows to identify the potential toxic effect related with their persistent accumulation in organs, 47 as concerns have been raised on the potential risk of using NPs in medical applications. ...
... The choice of 50% lethality of amlodipine as a standard is to avoid the potential uncertainty of making measurements. Additionally, LD50 is a widely accepted method for measuring the acute toxicity of drugs [18]. ...
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Context: Calcium channel blocker (CCB) poisonings are the leading cause of death from cardiovascular medication-related overdoses. Current treatments (calcium salts, vasopressors, inotropes) are often insufficient. Intravenous lipid emulsion (ILE) and methylene blue (MB) show promise in treating CCB overdoses unresponsive to conventional therapy. Objective: To compare the effectiveness of MB versus ILE in a rodent model of amlodipine (AML) poisoning with survival as the primary outcome and hemodynamic parameters as secondary outcomes. Materials and methods: Sixty-four adult male albino rats were anesthetized and cannulated for non-invasive hemodynamic measurement. Rats received amlodipine intraperitoneally (42 mg/kg). We then divided the rats into four groups: AML only without antidote, AML followed by ILE (24.8 mL/kg over 10 min), AML followed by normal saline (an equivalent volume of ILE), and AML followed by IV MB (2 mg/kg over 5 min). They received study treatments at 5, 30, and 60 minutes from the start of the protocol and with observation for 2 hours. Results: Survival time in ILE group was greater than in the control and NS groups. Differences between ILE and MB and between MB and NS were not significant. Hemodynamic parameters significantly increased in ILE group compared to the MB group at the 30, 60 and 120 min assessments but not after induction of AML poisoning and at 5 min assessment. Conclusions: Survival was greatest in rats treated with ILE. Both MB and NS had little effect on survival when compared to control animals. Both ILE and MB improved hemodynamics.
... It could be used as an agent for cytoprotective [100] . Furthermore, the LD50 of FVCO is determined as 5000mg/kg, considering that amount has been reported to have no lethal activity [101] . ...
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This review summarizes the background of Cocos nucifera, the benefits of the isolated virgin coconut oil (VCO), such as its potential as an adjunctive treatment for COVID-19, and its pharmacological effects, including antiviral and anti-inflammatory properties that could be applicable for therapeutic purposes against viral diseases. Observational studies, randomized, double-blind controlled intervention trials, and nonrandomized studies comprise this review that served as a basis. Consequently, from these summarized reports, the substances present in the VCO exhibit antiviral and immunomodulatory activity adjunct with antiviral drugs, which could prevent host cell infection and viral infection replication or reduce the inflammatory effects of COVID-19. Even though there are several studies of VCO in relation to its pharmacological properties, no recent studies have considered the implementation of the secondary metabolites present in virgin coconut oil as an adjunct to COVID-19 treatment. Therefore, further human clinical and observational studies for VCO are needed to suffice the need for evidence in regard to its potential use as an adjunctive treatment against COVID-19.
... These results revealed that the LD50 value of P. americana seed was estimated to be greater than 5000 mg/kg. This places the seed fraction in class 5 status (LD50 > 5000 mg/kg), i.e., in the lowest toxicity class [49] according to OECD labelling and classification of acute systemic toxicity. The ethyl acetate fractions of these plants are considered generally safe for animal consumption up to 5,000 mg/kg b.wt. ...
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Aims: Persea americana (P. americana) dubbed ‘green gold’ is a highly sought after fruit today, with insatiable export market. Different parts of avocadoes have been consumed both for nutritional and health benefits across regions of the world. Therefore, this study investigates the bioactive composition of P. americana seed ethyl acetate fraction and acute toxicological effects. Place and duration of study: Department of Biochemistry, Federal University of Technology Owerri, Imo State, Nigeria; between May 2019 and October, 2019. Methodology: Quantitative phytochemical composition was assessed using gas chromatography fitted with flame ionization detector (GC-FID) and acute toxicity determined using standard method. Results: Result of quantitative phytochemical composition of P. americana seed fraction shows a rich presence of phytochemicals such as epicatechin, kaempferol, proanthocyanin, rutin, resveratrol, ribalinidine, naringin, spartein, quinine, flavan-3-ol, anthocyanin, lunamarin, sapogenin, flavonones, flavones. The quantitative phytochemical composition of P. americana seed shows that among other phytochemicals, the seed is relatively rich in anthocyanin, quinine, epicatechin, tannin and proanthocyanin with concentrations of 69.39 ± 8.33 µg/g, 22.16 ±1.77 µg/g, 21.88 ± 2.53 µg/g, 19.86 ± 1.19 µg/g and 10.98 ± 0.55 µg/g respectively. The acute toxicity studies on the seed reveal that the ethyl acetate fraction of P. americana seed did not elicit any lethal signs of morbidity and mortality at doses up to 5000mg/Kgb.wt. and are therefore considered generally safe. Conclusion: P. americana seed ethyl acetate fraction contains essential phytochemicals with useful phyto-medicinal and nutraceutical benefits. The implications of these findings are further discussed.
... Based on the results, the values of the median lethal dose (LD 50 ) for cells were calculated using Behrens' method (Zbinden & Flury-Roversi, 1981). ...
Article
Currently, we are dealing with ever-increasing pollution of the environment with metal and metal oxide nanoparticles. One type of these, zinc oxide nanoparticles (ZnO-NPs), are increasingly used in areas such as cosmetology, electrical engineering, medicine, and even in the food and textile industries. As a consequence, ZnO-NPs may enter the human body in many ways. Their influence on the body is still not clear. Here, we define the mechanism of the initial toxicity of ZnO-NPs to cells based on interaction with the lipid part of the native and model cell membrane. The selected cell lines react differently to contact with nanoparticles. We found a disruption of the native membranes of B16-F0 cells and to a lesser extent of COLO 679. In turn, the membrane of COLO 679 cells was more peroxidated, and cell viability was much lower. A model of the lipid part of the membrane was created for B16-F0 cells and compared with previously published studies on immune cells. On the basis of physicochemical parameters obtained for individual lipids and a mix representing the native membrane of the tested cells, we concluded that exposure to nanoparticles resulted in a change within the model membranes (specifically with the polar parts of lipids). The greatest interaction has been noticed between ZnO-NPs and zwitterionic phospholipids (PC and PE), cholesterol, and negatively charged phosphatidylglycerol. Assessing the interactions between the membrane and nanoparticles will help to better understand the first steps of its toxicity mechanism.
... OECD Guidance Document 34) (OECD, 2005). It is in itself a challenge to estimate an LC 50 in rodents (Sperling and McLaughlin, 1976;Zbinden and Flury-Roversi, 1981), so comparison to the outcome of a mechanistically anchored in vitro method, with the aim of a correlation, seems hardly possible. ...
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To date there are no OECD validated alternative approaches to study toxicity following inhalation exposure to airborne chemicals. The available OECD test guidelines for acute inhalation toxicity aim to estimate a value of the lethal air concentration of the test chemical leading to the death of 50% of the exposed animals (LC50), to satisfy hazard classification and labelling requirements. This paper explores the view that alternative approaches must compare to outcomes of existing guideline methods to become accepted and implemented in a regulatory context. This case study describes the initiatives taken to validate the lung surfactant bioassay, an in vitro cell-free method, and discusses the challenges faced. While the lung surfactant bioassay could not predict the GHS classification for acute inhalation toxicity of 26 chemicals, the assay successfully predicted the clinical signs of respiratory toxicity observed during or shortly after exposure in vivo as reported in registration dossiers. The lung surfactant bioassay is a promising alternative approach to assess the potential of chemicals to cause changes to respiration remaining after exposure (indicating impaired lung function), and can be combined with other test methods in an integrated approach to testing and assessment of inhaled substances.
... However, in all the leaf extracts the dose-response slopes were more or less identical, suggesting a common mechanism of death. Hence, LC 50 is of great significance as biological constant in biological data analysis (Zbinden andFlury-Roversi 1981, Wallance-Hayes 1982). ...
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During the study, the leaves of two medicinal plants, Polygonum hydropiper and Abrus precatorius were extracted with water, ethanol, methanol and petroleum ether solvents and tested against the rice weevil S. oryzae L. for insecticidal properties. Response varied with plant species. The mortality of adults increased with increasing dose concentrations from 1000 ppm to 5000 ppm each solution, with an exposure time of 72 hours. LC 50 values calculated were found to be 15091.436 ppm with water, 5051.534 ppm with ethanol, 5111.063 ppm with methanol and 4305.348 ppm with petroleum ether extracts of P. hydropiper and 9687.292 ppm with water, 6263.849 ppm with ethanol, 4682.683 ppm with methanol and 3222.984 ppm with petroleum ether extracts of Abrus precatorius leaves corresponding their concentrations of the leaf extract solutions at 1000ppm, 2000 ppm, 3000 ppm, 4000 ppm and 5000 ppm respectively. The results of the study showed that methanol and petroleum ether extrcts of P. hydropiper and ethanol, methanol and petroleum ether extracts of A. precatorius showed good toxicity. It appeared that the leaf extracts had some insecticidal activities against S. oryzae adult.
Article
The number of deaths from the abuse of psychoactive drugs is increasing year after year, and new designer psychoactive drugs of unknown toxicity frequently appear on the streets. Human lethal drug doses generally do not correlate well with animal LD50 values. In order to investigate whether that holds for psychoactive drugs, human lethal dose values and rat and mouse LD50 values for several routes of administration for eighteen such drugs were collected from the literature. Quantitative toxicity-toxicity relationship (QTTR) regression correlations of human and rodent lethal doses were poor for both rat and mouse oral and intraperitoneal lethal doses, but both rat and mouse intravenous LD50 values correlated very well with human lethal doses (r2 = 0.823 and 0.756, respectively). Rat and mouse intravenous LD50 values predicted from commercial software also correlated reasonably well with human lethal doses (r2 = 0.631 and 0.678, respectively). This means that it should be possible to use these correlations to predict the human lethal doses of new psychoactive drugs.
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Objective: RJ a honey bee product has a high medicinal values to treat various diseases such as cancer, inflammation, various skin problems etc. current study was designed for the determination of oral medium lethal dose (LD50 value) of RJ. Material and Method: The study was directed according to OECD 423 guidelines by using male Swiss albino mice weighing 20-25 gms. all were divided into six groups. Group G1 was served as control group which received normal saline (NS) while group G2 to G6 were orally treated with single daily dose of 100, 500, 1000, 2000 and 5000 mg/kg of RJ, respectively. All the animals were closely observed for any sign of toxicity illness and behavioral changes. Results: Obtained results demonstrated that no mortality was observed in all treatment groups for post 24 hours but the dose 2000mg/kg show mortality at 14 th day while high dose up to 5000 mg/kg exhibited mortality at day 7 and 14 days observation duration. Conclusion: In conclusion, acute exposure of RJ up to 2000 mg/kg was safe in male mice without causing any adverse effects or mortality. The oral LD50 of Rj suggested to be greater than 1616 mg/kg in male mice.
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Here we report studies on the synthesis of 12 new heterocyclic derivatives that differ in three structural motifs and the simultaneous evaluation of the impact of these three variables on the biological properties. The examined compounds are based on rhodanine and 2-thiohydantoin cores equipped with hydrogen or carboxymethyl substituents at the N-3 position and linked to a triphenylamine moiety through 1,4-phenylene, 1,4-naphthalenylene and 1,9-anthracenylene spacers at the C-5 position of the heterocycles. All the compounds were synthesized very quickly, selectively and in high yields according to the developed microwave-assisted Knoevenagel condensation protocol, and they were characterized thoroughly with NMR, FT-IR and ESI-HRMS techniques. The derivatives were tested for their activity against selected strains of Gram-positive and Gram-negative bacteria and yeast. Two compounds showed good activity against Gram-positive bacteria, and all of them showed low cytotoxicity against three cell lines of the human immune system. Based on membrane permeability assays it was demonstrated that the active compounds do not penetrate the cell membrane, and thus they must act on the bacterial cell surface. Finally, we proved that the evaluated structure modifications had a synergistic effect and the simultaneous presence of a 1,4-phenylene spacer and carboxymethyl group at N-3 caused the highest boost in antimicrobial activity.
Article
Liverpool John Moores University and FRAME conducted a joint research project, sponsored by Defra, on the status of alternatives to animal testing with regard to the European Union REACH (Registration, Evaluation and Authorisation of Chemicals) system for the safety testing and risk assessment of chemicals. The project covered all the main toxicity endpoints associated with REACH. This paper focuses on the use of alternative (non-animal) methods (both in vitro and in silico) for acute systemic toxicity and toxicokinetic testing. The paper reviews in vitro tests based on basal cytotoxicity and target organ toxicity, along with QSAR models and expert systems available for this endpoint. The use of PBPK modelling for the prediction of ADME properties is also discussed. These tests are then incorporated into a decision-tree style, integrated testing strategy, which also includes the use of refined in vivo acute toxicity tests, as a last resort. The implementation of the strategy is intended to minimise the use of animals in the testing of acute systemic toxicity and toxicokinetics, whilst satisfying the scientific and logistical demands of the EU REACH legislation.
Article
Less than a quarter of all experimental animals in Europe are used in toxicological experiments, and most of these are performed by the pharmaceutical industry. Acute toxicity testing, mainly LD50 tests, accounts for a large proportion of toxicological studies. There are no defined animal numbers for special safety requirements in the Federal Republic of Germany (FRG). However, where the registration of chemical products in the FRG is concerned, numbers of animals used are documented.
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Nanosized natural polymers have attained considerable attention in drug delivery applications due to their high encapsulation efficiency, non-toxic nature, sustained and targeted drug delivery. Here we have synthesized Rifampicin loaded alginate nanoparticles by green method. Physicochemical characterization of the nanoparticles was assessed using Transmission electron microscopy, Fourier transform infrared spectroscopy, Dynamic light scattering and X-ray diffraction technique. The swelling and in vitro drug release showed that the framework experiences pH-dependent swelling and release of Rifampicin. Rifampicin has lower release in acid medium and higher release in intestinal condition. Moreover, in view of the drug release results, the release kinetics and transport mechanisms were investigated and discussed. In vitro cytotoxicity assay demonstrated that the nanoparticles were non-toxic in nature. The acute oral toxicity study of the synthesized nanoparticles was done in Wistar albino rats. No systemic toxicity was observed after oral administration of nanoparticles. The present study demonstrated the potential of using alginate nanoparticles synthesized by a green method for drug delivery applications.
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Rodent LD50 values have been used for almost a century as a measure of potential human toxicity from drugs and other chemicals. However, they have been found not, on the whole, to be good models for human toxicity. One reason for this could be the often-high variability of LD50 values. It has recently been shown that by using median LD50 values, very good correlations have been found with human lethal dosages. Bearing in mind the millions of rodent lives sacrificed, many with no good reason, it is proposed that some reparation could be made by more investigations using median values of already available rodent LD50 values.
Chapter
The adoption of herbicides as a weed control strategy has allowed farmers to reduce the short-term effects of biological adversities on crop yields. However, they have also jeopardized agroecosystem sustainability by causing negative alterations of social and environmental subsystems. The physicochemical properties of herbicides (volatility, adsorption, or water solubility) can make them persist in the soil, air, and water, changing the structure and function of key environmental compartments. The occurrence of herbicide-resistant weed populations has generated a positive feedback loop requiring the application of higher doses, aggravating negative externalities. Hence, the economic benefits of herbicides as a unique control strategy substantially decrease in time. In addition, the dependence of agricultural systems on external inputs generates an herbicidal “lock-in” process that hinders the transition towards more sustainable integrated management systems. Therefore, there is a pressing need to elucidate the principal aspects of environmental risk analysis of herbicide use in agroecosystems. The objectives of this chapter are: (1) to introduce key concepts related to the construction and application of environmental risk indicators with a focus on agricultural system risk assessment, (2) to list the potentially negative effects associated with the use of herbicides, (3) to understand the processes that regulate herbicides’ fate and behavior in farming systems, (4) to highlight the importance of decision support systems (DSS) in reducing herbicide use in favor of integrated weed management (IWM), and (5) to understand the decision-making logic behind the increasing adoption of chemical weed control despite its negative socio-environmental effects.
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Biomedical endeavours can be divided into three major categories: research, education, and testing. Within the context of each of these categories, activities involving whole animals have made major contributions and will continue to do so in the future. However, with technological developments in the areas of biotechnology and computers, new methods are already reducing the use of whole animals in certain areas. This article discusses the general issues of alternatives and then focuses on the development of new approaches to toxicity testing.
Article
Animal models are generally used to elucidate human physiology or pathology. However, attempts to extrapolate animal model findings to humans are undermined by differences in the aetiology and natural history between any animal model condition and the analogous human condition, and by unavoidable interspecies differences in anatomy and physiology. Even when working with species “closely related” to humans, such as chimpanzees, the animal model paradigm is fundamentally unsound. Unfortunately, few animal researchers seriously question the utility of animal models, and consequently they rarely consider other, perhaps more efficient and more reliable, means of conducting biomedical research.
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Over a period of two years the Scandinavian Society for Cell Toxicology* has met three times (on 21 October 1983 and 6–7 June 1984 in Uppsala, Sweden, and on 6–7 September 1985 in Roskilde, Denmark), to present research advances in cell toxicology and to discuss the effects of xenobiotics in isolated and cultured cells. The first part of this report represents a summary of these discussions. In the second part, some of the individual research reports presented by the participating members are summarised. The purpose is to give a review of problems currently dealt with in Scandinavian laboratories associated with the Society for Cell Toxicology.
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Background: Up-and-down procedure (UDP) was recommended to replace traditional acute toxicity methods. However, it was limited due to the long experimental period (20 - 42 days). To improve UDP, an improved UDP method (iUDP) was developed by shortening observation time between sequence dosages. The aim of this study was to test the reliability of iUDP to provide a reliable method for the acute toxicity measurement of valuable or minor amount compounds. Methods: Oral median lethal dosage (LD50) of nicotine, sinomenine hydrochloride and berberine hydrochloride were measured both by iUDP and modified Karber method (mKM). Results: LD50 of the three alkaloids measured by iUDP with 23 mice were 32.71 ± 7.46, 453.54 ± 104.59, 2954.93 ± 794.88 mg/kg, respectively. LD50 of the three alkaloids measured by mKM with 240 mice were 22.99 ± 3.01, 456.56 ± 53.38, 2825.53 ± 1212.92 mg/kg, respectively. The average time consumed by the two methods were 22 days and 14 days respectively. Total grams of the alkaloids used by the two methods were 0.0082 and 0.0673 (nicotine), 0.114 and 1.24 (sinomenine hydrochloride), 1.9 and 12.7 (berberine hydrochloride). Conclusion: iUDP could replace mKM to detect acute toxicity of substances with comparable and reliable result. And it was suitable for valuable or minor amount substances.
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Studies on the phytochemical and macronutrient composition of the leaves of Combretum dolichopentalum were carried out. The qualitative phytochemical composition shows the presence of alkaloid, flavonoid, saponin, tannin, steroid, glycosides and resins. The quantitative phytochemical composition shows that it contains 5.765 ± 0.002 mg/100g tannin, 80±0.003 mg/100g flavonoids, 0.033±0.003 mg/100g cyanide, 8.717± 0.003 mg/100g alkaloids, 17.86 ± 0.002 mg/100g saponins and 6.969±0.005 mg/100g steroid. The macronutrients obtained include 2.101±0.003 mg/100g soluble carbohydrate and 200.0±0.002 mg/100g reducing sugar. The result of acute toxicity (LD 50), showed C. dolichopentalum leaf extract to be lethal at doses 3000 and 5000 mg/kg body weight. This study revealed that C. dolichopentalum is a rich source of phytochemical and reducing sugar, which if adequately processed will not only offer chemoprotective benefits to its users, but could also serve as a good source of nutrient.
Article
Silver nanoparticles (AgNPs) prepared and stabilized by diverse biologically active substances seem to be especially useful in diverse biological and medical applications. The combination of AgNPs with bioactive substances, such as antioxidants, can lead to the development of new systems of desired anticancer properties. In this research, AgNPs were prepared with the use of diverse antioxidant combinations including gallic acid (GA), (-)-epicatechin-3-gallate (EGCG), and caffeine (CAF). The insightful physicochemical characteristic revealed that each type of AgNPs exhibited spherical shape, comparable size distribution and negative surface charge. Surface-enhanced Raman spectroscopy (SERS) delivered the information about the chemistry of AgNP stabilizing layers, which turned out to be a crucial factor tuning toxicity of AgNPs toward murine B16 melanoma cells (B16-F0) and human skin melanoma (COLO 679) cells. EGCGAgNPs were the most cytotoxic among all the investigated AgNPs. They strongly reduced the activity of mitochondria, damaged cell membrane integrity, and penetrated inside the cells causing DNA damage. In turn, the toxicity of GAAgNPs strongly manifested via the induction of oxidative stress in the cells. It was found that CAFGAAgNPs exhibited the lowest toxicity toward the melanoma cells, which proved that a proper combination of antioxidants enable to prepare AgNPs of differentiated toxicity. It was established that human skin melanoma cells were significantly more sensitive to AgNPs than the murine melanoma cells.
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Background : Intentional or unintentional ingestion of organophosphate compounds is a common cause of death due to poisoning specially in rural areas of developing countries. Objective: In this study effects of atropine sulfate and scopolamine hydrobromide were compared with respect to modification of LD50 of malathion. Design : Animal experimental study was carried out in albino mice. Result : It was observed that LD50 of Malathion was increased more by scopolamine hydrobromide than atropine sulfate.
The third edition of Gleason, Gosselin, and Hodge remains an essential volume for any Pediatric Emergency Service or for any doctor dealing at all commonly with poisonings. With the addition of one more author, Roger P. Smith, PhD, and a change in cover color to bright blue, this new volume should be placed alongside the two prior editions rather than replace them since some of the previously listed products have been dropped as obsolete and yet, still may exist to cause a rare poisoning. Basically, the third edition is unchanged as to format; the same seven sections: (1) first aid and general treatment, (2) ingredient index and toxicity ratings, (3) therapeutic discussions of specific poisons, (4) supportive treatment, (5) trade name product index and contents, (6) general formulations of common classes of commercial products such as drainpipe cleaners or hair sprays, and (7) index of manufacturers with addresses. Much of
Article
A log-probit graph paper is described by which a simple graphic estimation of the ED50 and its standard error may be quickly made.
Chapter
This chapter discusses the experimental and clinical aspects of drug toxicity. With the development of an increasing number of new and often very potent medicaments the problem of drug-induced toxicity has become a matter of major concern. The history of every new substance is almost invariably marked by an early and enthusiastic acclaim for its novel therapeutic potential which is often followed by a condemnation due to the occurrence of the seemingly inevitable side actions. This phase is usually followed by a more realistic appraisal of the new compound and recognition of its range of usefulness, contraindications, and dangers. Since there is probably no biologically active substance which does not exhibit some undesirable effects, drug-induced toxicity will always accompany the progress made in drug therapy. It would be very desirable if the harmful effects of newly developed compounds could be recognized in animals before any damage is done to human subjects. For that reason it has become a standard practice to subject every drug to extensive trials in laboratory animals prior to their release for human use.
Article
The relationship between the metabolic disposition of acetaminophen and the susceptibility of hamsters, mice and rats to acetaminophen-induced liver necrosis has been examined. The fraction of low doses of acetaminophen converted to the mercapturic acid metabolite was highest in the most susceptible species (hamsters, mice), and lowest in the more resistant species (rat). Pretreatment regimens known to potentiate the hepatotoxicity increased mercapturic acid formation whereas treatments which protect from liver damage decreased mercapturic acid formation. The data suggest that the activity of the mercapturic acid-forming pathway in vivo reflects the activity of the hepatotoxic pathway. As the dose of acetaminophen was increased to hepatotoxic levels, the fraction of the dose excreted as the mercapturic acid decreased markedly, commensurate with the known depletion of hepatic glutathione under these conditions. It is suggested that the normal metabolic intermediate which conjugates with glutathione in the mercapturic acid pathway is also the electrophilic metabolite which in the absence of glutathione arylates hepatic macromolecules and causes cell death.
Article
Ten chemicals were administered orally to male albino rats by 8 industrial or commercial toxicology laboratories. In each laboratory, the LD50 for each chemical was determined using three different protocols: (a) a reference protocol using a reference stock of rats, (b) the same reference procedure using the rats commonly used by each laboratory and (c) the procedure and rats generally used by each laboratory. The results of this round robin study denoted certain laboratories with consistent bias; one, using pathogen-free rats, had high LD50's and another laboratory had consistently low LD50's. The latter laboratory also had consistently high fiducial ranges.The effects of fasting, change of stock, different diets, various intubation methods, etc. were compared between laboratories and within the same laboratory. Overall, the effects of different stocks were slight, except in a laboratory using a rapidly growing rat and in the one using the pathogen-free rat. A procedure using nonfasted, mature rats was related in one laboratory to higher LD50's. The use of female rats was related to lower LD50's.The fiducial range was again shown to be somewhat related to the geometric factor between dosage levels. The LD50's were not affected by this factor.Generally, only a few significant interlab differences in LD50's and fiducial ranges were found between the reference or nonstandard protocols.
Article
The sigmoid dosage-mortality curve, secured so commonly in toxicity tests upon multicellular organisms, is interpreted as a cumulative normal frequency distribution of the variation among the individuals of a population in their susceptibility to a toxic agent, which susceptibility is inversely proportional to the logarithm of the dose applied. In support of this interpretation is the fact that when dosage is inferred from the observed mortality on the assumption that susceptibility is distributed normally, such inferred dosages, in terms of units called probits, give straight lines when plotted against the logarithm of their corresponding observed dosages. It is shown that this use of the logarithm of the dosage can be interpreted in terms either of the Weber-Fechner law or of the amount of poison fixed by the tissues of the organism. How this transformation to a straight regression line facilitates the precise estimation of the dosage-mortality relationship and its accuracy is considered in detail. Statistical methods are described for taking account of tests which result in 0 or 100 per cent, kill, for giving each determination a weight proportional to its reliability, for computing the position and slope of the transformed dosage-mortality curve, for measuring the goodness of fit of the regression line to the observations by the X2 test, and for calculating the error in position and in slope and their combined effect at any log. dosage. The terminology and procedures are consistent with those used by R. A. Fisher, who has contributed an appendix on the case of zero survivors. Except for a table of common logarithms, all the tables required to utilise the methods described are given either in the present paper or in Fisher's book. A numerical example selected from Strand's experiments upon Tribolium confusum with carbon disulphide has been worked out in detail.
Article
Es wird ein Verfahren zur kollektiven Behandlung von Reihenversuchen angegeben, das gestattet, auch bei kleinerem Umfang des Kollektivs (Reihenversuch mit vier bis fnf Gruppen zu je sechs Tieren) und bei starker Streuung zu einem zahlenmigen Ausdruck des Versuchsergebnisses zu gelangen.
Article
1. Die individuelle Streuung der Giftempfindlichkeit von Frschen gegen Strophanthin und auch Digitalisglykoside wird sowohl bei intravenser Zufuhr wie bei Einspritzung in den Lymphsack zu rund 20% gefunden. 2. Es wurden Untersuchungen ber die Brauchbarkeit der Vorschriften des Deutschen Arzneibuches fr die Auswertung von Digitalisglykosiden ausgefhrt, aus denen hervorgeht, da das Verfahren der Katzenmethode nicht unterlegen ist. 3. Es wird ein neues Berechnungsverfahren beschrieben, durch das der Zentralwert mit grerer Genauigkeit erfat werden kann. 4. Es wird ein Verfahren beschrieben, das gestattet, Versuchstieren kleine Mengen einer Giftlsung (0,01 ccm) im Verlauf 1 Stunde mit konstanter Geschwindigkeit intravens einlaufen zu lassen.
Article
The maximal tolerated dose and the minimal lethal dose in mice are estimated for a series of twenty flucrine-containing organic compounds, four inorganic compounds of fluorine, and three nonfluorine-containing organic compounds.
Article
A screening procedure has been described for estimating the hepatotoxic potential of industrial solvents in mice. Data on lethality, barbiturate sleeping time, and bromosulfalein retention, coupled with minimal histologic examination, were employed to determine the individual hepatotoxic potency and relative hepatotoxic potencies for nine halogenated methane derivatives. A method has been described for estimating the industrial hepatotoxic hazard by these data.
Article
The standard method of dealing with sensitivity of dosage-mortality data is the probit technique developed by Bliss and Fisher. This paper provides an alternative technique based on a special system for obtaining such data. It has some advantages when observations must be taken on individuals rather than groups of individuals, and it may be preferred in certain other situations.
Article
Single doses of 100, 200, 300, and 400 mg diquat ion/kg body wt were administered by stomach tube to cynomolgus monkeys. Within 4 days of dosing deaths occurred in , , , and monkeys, respectively. All animals developed diarrhea and the most severely affected became comatose. The most important histopathological changes were necrosis of the epithelium and villi of the gastrointestinal tract and of the epithelium of the proximal and distal convoluted tubules of the kidneys.
In 1977, the Commission of the European Communities initiated an intercomparison study to determine the single administration oral LD50 value in rats of each of 5 chemicals with the aims of comparing experimentation technologies, determining the degree of variation in the results and the various parameters used to establish the LD50 value, and establishing a common protocol for the determination of the LD50 value. Sixty-five laboratories in 8 countries took part in the first study. The significant variation in protocol may have led to the large interlaboratory variation observed in the results. Therefore, participating laboratories carried out a second study using a common protocol, preceded by a pilot study. A total of 100 laboratories in 13 countries participated. A majority of results of the second study are currently being analyzed, and the indications are that the interlaboratory variation has been significantly reduced.
Article
Albino rats were fed for 28 days from weaning on diets containing no protein (group I), one-seventh of the optimal protein intake (group II), one-third of the optimal protein (group III), the optimal protein level, as 26% casein (group IV), or three times the optimal protein intake (group V). At the end of the dieting period, the acute oral LD50 ± SE of captan was found to be (in mg/kg body weight) 6·15 ± 3·1 in group I, 480 ± 110 in group II, 10,670 ± 2800 in group III, 12,600 ± 2100 in group IV and 5320 ± 1420 in group V. The interval to death extended from 5 hr to 7 days, averaged 53 hr, was shorter the higher the dose of captan, and was not consistently influenced by the amount of protein in the diet. Animals in group I were some 2000 times more susceptible to the toxic effects of captan than were controls of group IV, compared with some 12 times for lindane and monuron, eight times for carbaryl, chlorpropham and diazinon and four times for dicophane (DDT). The results indicate that further studies should be made upon captan, which could well be a hazardous pesticide to employ in countries where the diet is low in protein.
Article
The relationship between the metabolic disposition of acetaminophen and the susceptibility of hamsters, mice and rats to acetaminophen induced liver necrosis has been examined. The fraction of low doses of acetaminophen converted to the mercapturic acid metabolite was highest in the most susceptible species (hamsters, mice), and lowest in the more resistant species (rats). Pretreatment regimens known to potentiate the hepatotoxicity increased mercapturic acid formation whereas treatments which protect from liver damage decreased mercapturic acid formation. The data suggest that the activity of the mercapturic acid forming pathway in vivo reflects the activity of the hepatotoxic pathway. As the dose of acetaminophen was increased to hepatotoxic levels, the fraction of the dose excreted as the mercapturic acid decreased markedly, commensurate with the known depletion of hepatic glutathione under these conditions. It is suggested that the normal metabolic intermediate which conjugates with glutathione in the mercapturic acid pathway is also the electrophilic metabolite which in the absence of glutathione arylates hepatic macromolecules and causes cell death.
Article
Isoproterenol HCl causes an ischemic myocardial necrosis in animals which is due to its exaggerated cardiovascular effects. The influence of restricted food intake on the cardiotoxicity of this compound was studied in Sprague-Dawley male rats of 3–7 mo of age. They were fed ad libitum or restrictedly (about 50%) for various periods. The latter became less susceptible to the cardiotoxic effect of isoproterenol HCl than their freely fed controls. The resistance acquired following the restricted intake of food persisted for 1 wk upon return to ad libitum feeding.The cardiac pharmacologic effect of isoproterenol HCl (the degree and duration of tachycardia) was the same in rats fed freely or restrictedly. It is postulated that restricted intake of food increased the resistance to the ischemic effect of isoproterenol.
Article
A tabulation of LD50 values for newborn and adult mammals has been compiled from the literature and from the files of the Food and Drug Administration.
Article
Prolonged individual caging of rats, as is sometimes employed in long-term toxicity tests, was accompanied by several changes in parameters of toxicity. In comparison to community-housed animals of same age and sex, acute LD50s might be increased or decreased. Pentobarbitone and chloral hydrate sleeping times were reduced and the induction period for the loss of righting reflex with sodium amytal was prolonged. The extent of these changes was dependent upon the length of isolation, sex, and strain. A possible explanation for these altered toxic responses was that the adrenergic or ergotropic component of the central nervous system had undergone an increase in activity in the isolated animals.
Article
The death rates from 12 different drugs given orally to mice and rats were higher, the greater the dilution of the dose in water. A similar relationship was noted between the oral LD50 in mice and dilution of the dose of 4 different drugs.
Expert Committee of Food Additives) (1974) Toxicological evaluation of certain food additives with a review of general principles and of specification
  • Jecfa Joint
Die toxikologischen Voraussetzungen für die klinische Anwendung einer neuen Substanz In: von Eickstedt KW, Gross F (Hrsg) Aus Klinische Arzneimittelprüfung
  • Neubert
Clinical toxicology of commercial products Acute poisoning A compilation of LDs0 values in newborn and adult animals
  • Gleason Mn
  • Re Gosselin
  • Hodge
  • Hc
  • Smith
Gleason MN, Gosselin RE, Hodge HC, Smith RP (1969) Clinical toxicology of commercial products. Acute poisoning, 3rd ed. Williams and Wilkins Co., Baltimore Goldenthal EI (1971) A compilation of LDs0 values in newborn and adult animals. Toxicol Appl Pharmacol 18:185-207
Vergleich der im Tierexperiment und beim Menschen t6dlichen Dosen wichtiger Pharmaka Diss Univ Frankfurt/Main Neubert D (1975) Die toxikologischen Voraussetzungen fiir die klinische Anwendung einer neuen Substanz
  • Moiler
MOiler R (1948) Vergleich der im Tierexperiment und beim Menschen t6dlichen Dosen wichtiger Pharmaka. Diss Univ Frankfurt/Main Neubert D (1975) Die toxikologischen Voraussetzungen fiir die klinische Anwendung einer neuen Substanz. In: yon Eickstedt KW, Gross F (Hrsg) Aus Klinische ArzneimittelprOfung. Symposium fiir klinische Pharmakologie des Bundesgesundheitsamtes Berlin. Fischer, Stuttgart, S. 22-42
Effects of temperature on the action of drugs Reports on biological standards III methods of biological assay depending on a quantal response
  • Fuhrman Gj
  • Fuhrman
  • Fa
Fuhrman GJ, Fuhrman FA (1961) Effects of temperature on the action of drugs. Ann Rev Pharmacol 1 : 65-78 Gaddum JH (1933) Reports on biological standards III methods of biological assay depending on a quantal response. MRC Special Report. M.S.O. London, Ser No 183
The purpose and value of LDs0 determinations. Historical introduction
  • Morrison
  • Quinton Rm Jk
Morrison JK, Quinton RM, Reinert H (1968) The purpose and value of LDs0 determinations. Historical introduction. In: Boyland E, Goulding R (eds) Modern trends in toxicology Butterworths, London, p 1
Reports on biological standards III methods of biological assay depending on a quantal response
  • J H Gaddum
  • JH Gaddum
Toxicological effects testing Guidebook, toxic substances control act
  • T Ellison