Toxicology: Then and now

Forensic Mass Spectrometry: Scientific and Legal Precedents

Mass spectrometry has made profound contributions to the criminal justice system by providing an instrumental method of analysis that delivers exquisite analytical figures of merit for a wide variety of samples and analytes. Applications include the characterization of trace metal impurities in hair and glass to the identification of drugs, explosives, polymers, and ignitable liquids. This review describes major historical developments and, where possible, relates the developed capabilities to casework and legal precedents. This review also provides insight into how historical applications have evolved into, and out of, modern consensus standards. Unlike many pattern-based techniques and physical-matching methods, mass spectrometry has strong scientific foundations and a long history of successful applications that have made it one of the most reliable and respected sources of scientific evidence in criminal and civil cases. That said, in several appellate decisions in which mass spectrometric evidence was challenged but admitted, decisions sometimes still went against the mass spectrometric data anyway, which goes to show that mass spectrometric evidence is always just one piece of the larger legal puzzle.

In vitro toxicity of carbon nanotubes: a systematic review

Carbon nanotube (CNT) toxicity-related issues provoke many debates in the scientific community. The controversial and disputable data about toxicity doses, proposed hazard effects, and human health concerns significantly restrict CNT applications in biomedical studies, laboratory practices, and industry, creating a barrier for mankind in the way of understanding how exactly the material behaves in contact with living systems. Raising the toxicity question again, many research groups conclude low toxicity of the material and its potential safeness at some doses for contact with biological systems. To get new momentum for researchers working on the intersection of the biological field and nanomaterials, i.e., CNT materials, we systematically reviewed existing studies with in vitro toxicological data to propose exact doses that yield toxic effects, summarize studied cell types for a more thorough comparison, the impact of incubation time, and applied toxicity tests. Using several criteria and different scientific databases, we identified and analyzed nearly 200 original publications forming a "golden core" of the field to propose safe doses of the material based on a statistical analysis of retrieved data. We also differentiated the impact of various forms of CNTs: on a substrate and in the form of dispersion because in both cases, some studies demonstrated good biocompatibility of CNTs. We revealed that CNTs located on a substrate had negligible impact, i.e., 90% of studies report good viability and cell behavior similar to control, therefore CNTs could be considered as a prospective conductive substrate for cell cultivation. In the case of dispersions, our analysis revealed mean values of dose/incubation time to be 4-5 μg mL-1 h-1, which suggested the material to be a suitable candidate for further studies to get a more in-depth understanding of its properties in biointerfaces and offer CNTs as a promising platform for fundamental studies in targeted drug delivery, chemotherapy, tissue engineering, biosensing fields, etc. We hope that the present systematic review will shed light on the current knowledge about CNT toxicity, indicate "dark" spots and offer possible directions for the subsequent studies based on the demonstrated here tabulated and statistical data of doses, cell models, toxicity tests, viability, etc.

Venoms and poisonings during the centuries. A narrative review

Suffice it to say that the first traces of its use by man date back to ten thousand years ago the venom or poison since the last period of the Paleolithic man used poison to hunt and for defence. Indeed, in the second half of the 19th century, was found in some caves arrows made from the bones of animals characterized by particular grooves. In ancient Greece, the term pharmakon (φάρμακον) had a double meaning: remedy for therapy and venom. This is the period in which we become aware of the fact that a poison cannot be defined only as a substance capable of changing the properties of things. The poisonings are very frequent in the history of the Roman Empire and later in the Renaissance and the modern era. Poison was the protagonist political intrigues of power and is one of the most used lethal weapons over the years. Optimal solution for a perfect murder, the poison has a long history. Its success is due to the invisible and often unpunished death.

What the lab can and cannot do: clinical interpretation of drug testing results

Urine drug testing is one of the objective tools available to assess adherence. To monitor adherence, quantitative urinary results can assist in differentiating "new" drug use from "previous" (historical) drug use. "Spikes" in urinary concentration can assist in identifying patterns of drug use. Coupled chromatographic-mass spectrometric methods are capable of identifying very small amounts of analyte and can make clinical interpretation rather challenging, specifically for drugs that have a longer half-life. Polypharmacy is common in treatment and rehabilitation programs because of co-morbidities. Medications prescribed for comorbidities can cause drug-drug interaction and phenoconversion of genotypic extensive metabolizers into phenotypic poor metabolizers of the treatment drug. This can have significant impact on both pharmacokinetic (PK) and pharmacodynamic properties of the treatment drug. Therapeutic drug monitoring (TDM) coupled with PKs can assist in interpreting the effects of phenoconversion. TDM-PKs reflects the cumulative effects of pathophysiological changes in the patient as well as drug-drug interactions and should be considered for treatment medications/drugs used to manage pain and treat substance abuse. Since only a few enzyme immunoassays for TDM are available, this is a unique opportunity for clinical laboratory scientists to develop TDM-PK protocols that can have a significant impact on patient care and personalized medicine. Interpretation of drug screening results should be done with caution while considering pharmacological properties and the presence or absence of the parent drug and its metabolites. The objective of this manuscript is to review and address the variables that influence interpretation of different drugs analyzed from a rehabilitation and treatment programs perspective.

Chemophobia versus the identity of chemists: heroes of chemistry as an effective communication strategy

Abstract

Decades of chemophobia are taking a high toll on chemistry. As current surveys suggest, people are displaying an irrational desire to live in a world without chemistry, but at the same time are unable to answer trivial chemistry questions. Constant questioning of the importance of chemistry induced by chemophobia leads to a weakening of the identity of chemists and can have negative consequences on the reproduction of chemistry. The need for the support of a positive perception of the chemical profession and an offer of positive examples for self-identification is the result. Everyday communication thus becomes the background on which the determination of the identity of the chemist takes place. The new communication strategy, which we call “heroes of chemistry”, aims not only to add a much-needed human touch to chemistry communications, but also to create the conditions for strengthening the identity of the chemist.

Graphic abstract

A simple, cost-effective and rapid method for simultaneous determination of Strychnos nux-vomica alkaloids in blood and Ayurvedic medicines based on ultrasound-assisted dispersive liquid-liquid microextraction-thin-layer chromatography-image analysis

A simple, rapid, cost-effective and green analytical method is developed based on ultrasound-assisted dispersive liquid-liquid microextraction (US-DLLME) coupled to thin-layer chromatography (TLC)-image analysis for the simultaneous determination of two major alkaloids of Strychnos nux-vomica L i.e., strychnine and brucine. The method is composed of three steps, namely (i) US-DLLME by injecting a mixture of 100-μL chloroform (extraction solvent) and 1-mL methanol (disperser solvent) in 5 mL of aqueous sample, followed by ultrasonication and centrifugation, (ii) TLC of 20 μL of sedimented phase with methanol: ammonia (100:1.5, v/v) as the mobile phase and visualization under ultraviolet radiation (254 nm) and (iii) photography of TLC plate and quantification of spots by image analysis using freely available imageJ software (National Institute of Health, Bethesda, MD, USA). The limit of detection and limit of quantification for both alkaloids were found to be in the range of 0.12-0.15 and 0.36-0.48 μg/spot, respectively. The method was found to be linear in the range of 0.5-5 μg/spot with correlation coefficient (R2) of 0.995 and 0.997 for strychnine and brucine, respectively. The developed method was successfully applied for the determination of strychnine and brucine in Ayurvedic formulations and blood samples. The method does not require any sophisticated instrument and handling skills and can be adopted for rapid analysis of strychnine and brucine in forensic toxicological laboratories.

Blood lead and cadmium levels associated with hematological and hepatic functions in patients from an e-waste-polluted area

Chronic exposures to toxic trace metals have hazardous effects on human health, especially exposure to lead (Pb) and cadmium (Cd). Blood Pb and Cd reflect toxicity on human health. A total of 267 hospitalized patients, of which 158 were from Guiyu (exposed group) in China, and 109 from Jinping (reference group), were recruited in this study. Blood Pb and Cd were measured by graphite furnace atomic absorption spectrometry. Blood Pb and Cd levels from the exposed group were both higher than in the reference group. Blood Pb levels are positively associated with blood Cd levels from the two groups. Blood Pb and Cd levels are associated with elevated hematological and hepatic parameters in patients from the exposed and reference groups. The results suggest toxic trace metals may increase liver metabolic burden, inducing abnormal liver function.

The right blood collection tube for therapeutic drug monitoring and toxicology screening procedures: Standard tubes, gel or mechanical separator?

Stability data of toxics or drugs in gel-based or mechanical separation blood collection tubes are lacking, especially for therapeutic drug monitoring and clinical toxicology procedures. According to ISO 15189 accreditation standard, laboratories need to master the entire preanalytical process including the stability of analytes in a specific tube. Here we explored the impact of BD PST™ II and Barricor™ separator tubes on the stability of 167 therapeutic compounds and common drugs of abuse in plasma samples using LC-MS/MS. Forty drugs were significantly affected by the use of PST™ II tubes, including antidepressants (11/26), neuroleptics (9/13), cardiovascular drugs (5/26), anxiolytics and hypnotics (4/25) and some drugs of abuse (5/26). Six compounds exhibited significant reduction by the mechanical Barricor™ tubes. Ten drugs exhibited low (<85%) but non-significant recoveries due to inter-assay variability. Besides, a logP > 3.3 was determined as a cut-off value to predict a potential lack of stability in PST™ II gel tubes with an 86.4% sensitivity and a 61.4% specificity. As a consequence, determination of drugs with a logP > 3.3 should be carried out with caution in plasma samples withdrawn on PST™ II. The study showed the Barricor™ and non-gel tubes cause less drug interference and are recommended for the drugs studied.

Nuisance Compounds, PAINS Filters, and Dark Chemical Matter in the GSK HTS Collection

High-throughput screening (HTS) hits include compounds with undesirable properties. Many filters have been described to identify such hits. Notably, pan-assay interference compounds (PAINS) has been adopted by the community as the standard term to refer to such filters, and very useful guidelines have been adopted by the American Chemical Society (ACS) and subsequently triggered a healthy scientific debate about the pitfalls of draconian use of filters. Using an inhibitory frequency index, we have analyzed in detail the promiscuity profile of the whole GlaxoSmithKline (GSK) HTS collection comprising more than 2 million unique compounds that have been tested in hundreds of screening assays. We provide a comprehensive analysis of many previously published filters and newly described classes of nuisance structures that may serve as a useful source of empirical information to guide the design or growth of HTS collections and hit triaging strategies.

Metformin is not just an antihyperglycaemic drug but also has protective effects on the vascular endothelium

Metformin, a synthetic dimethyl biguanide, has been in clinical use for over 55 years, and today is considered the first-choice drug for the treatment of type 2 diabetes used by an estimated 125 million people worldwide. Metformin is orally effective, not metabolized, excreted unchanged by the kidney, relatively free of side effects and well tolerated by the majority of patients. Of importance is that the United Kingdom Prospective Diabetes Study 20-year study of type 2 diabetics, completed in 1998, compared patients treated with insulin, sulfonylureas and metformin and concluded that metformin provided vascular protective actions. Cardiovascular disease is the primary basis for the high morbidity and mortality that is associated with diabetes and that metformin proved to be protective resulted in a dramatic increase in its use. The vascular protective actions of metformin are thought to be secondary to the antihyperglycaemic effects of metformin that are mediated via activation of AMP kinase and subsequent inhibition of hepatic gluconeogenesis, fatty acid oxidation as well as an insulin sensitizing action in striated muscle and adipose tissue. As reflected by a number of clinical studies, patients treated with metformin also have improvement in endothelial function as measured by the use of plethysmography and measurement of flow-mediated vasodilatation. These data as well as data from animal studies are supportive that metformin has a direct protective action on the vascular endothelium. In this review article, we discuss the pharmacology of metformin and critique the literature as to its cellular sites and mechanism(s) of action.

Advances in Clinical Mass Spectrometry

Although mass spectrometry has been used clinically for decades, the advent of immunoassay technology moved the clinical laboratory to more labor saving automated platforms requiring little if any sample preparation. It became clear, however, that immunoassays lacked sufficient sensitivity and specificity necessary for measurement of certain analytes or for measurement of analytes in specific patient populations. This limitation prompted clinical laboratories to revisit mass spectrometry which could additionally be used to develop assays for which there was no commercial source. In this chapter, the clinical applications of mass spectrometry in therapeutic drug monitoring, toxicology, and steroid hormone analysis will be reviewed. Technologic advances and new clinical applications will also be discussed.

Current data regarding the structure-toxicity relationship of boron-containing compounds

Boron is ubiquitous in nature, being an essential element of diverse cells. As a result, humans have had contact with boron containing compounds (BCCs) for a long time. During the 20th century, BCCs were developed as antiseptics, antibiotics, cosmetics and insecticides. Boric acid was freely used in the nosocomial environment as an antiseptic and sedative salt, leading to the death of patients and an important discovery about its critical toxicology for humans. Since then the many toxicological studies done in relation to BCCs have helped to establish the proper limits of their use. During the last 15 years, there has been a boom of research on the design and use of new, potent and efficient boron containing drugs, finding that the addition of boron to some known drugs increases their affinity and selectivity. This mini-review summarizes two aspects of BCCs: toxicological data found with experimental models, and the scarce but increasing data about the structure-activity relationship for toxicity and therapeutic use. As is the case with boron-free compounds, the biological activity of BCCs is related to their chemical structure. We discuss the use of new technology to discover potent and efficient BCCs for medicinal therapy by avoiding toxic effects.

Cement Dust Exposure and Perturbations in Some Elements and Lung and Liver Functions of Cement Factory Workers

Background. Cement dust inhalation is associated with deleterious health effects. The impact of cement dust exposure on the peak expiratory flow rate (PEFR), liver function, and some serum elements in workers and residents near cement factory were assessed. Methods. Two hundred and ten subjects (50 workers, 60 residents, and 100 controls) aged 18–60 years were studied. PEFR, liver function {aspartate and alanine transaminases (AST and ALT) and total and conjugated bilirubin (TB and CB)}, and serum elements {lead (Pb), copper (Cu), manganese (Mn), iron (Fe), cadmium (Cd), selenium (Se), chromium (Cr), zinc (Zn), and arsenic (As)} were determined using peak flow meter, colorimetry, and atomic absorption spectrometry, respectively. Data were analysed using ANOVA and correlation at p = 0.05. Results. The ALT, TB, CB, Pb, As, Cd, Cr, Se, Mn, and Cu were significantly higher and PEFR, Fe, and Zn lower in workers and residents compared to controls (p < 0.05). Higher levels of ALT, AST, and Fe and lower levels of Pb, Cd, Cr, Se, Mn, and Cu were seen in cement workers compared to residents (p < 0.05). Negative correlation was observed between duration of exposure and PEFR (r = −0.416, p = 0.016) in cement workers. Conclusions. Cement dust inhalation may be associated with alterations in serum elements levels and lung and liver functions while long term exposure lowers peak expiratory flow rate.

Multi-target screening of biological samples using LC–MS/MS: focus on chromatographic innovations

Multi-target screening of biological fluids is a key tool in clinical and forensic toxicology. A complete toxicological analysis encompasses the sample preparation, the chromatographic separation and the detection. The present review briefly covers the new trends in sample preparation and detection and mainly focuses on the chromatographic stage, since a lot of technical improvements have been proposed over the last years. Among them, columns packed with sub-2 μm fully porous particles and sub-3 μm core-shell particles allow for significant improvements of resolution and higher throughput. Even if reversed-phase LC remains the most widely used chromatographic mode for toxicological screening, hydrophilic interaction chromatography and supercritical fluid chromatography appear as promising alternatives for attaining orthogonal selectivity, retention of polar compounds, and enhanced MS sensitivity.

Image Gently: a campaign to reduce children's and adolescents' risk for cancer during adulthood

Recently, the Cancer Prevention Across the Lifespan workgroup at the Centers for Disease Control held a workshop entitled "Identifying Opportunities for Cancer Prevention During Pre-Adolescence and Adolescence." With the goal of raising awareness and developing community and policy interventions to decrease risk factors for cancer, one session highlighted the danger of ionizing radiation exposure from diagnostic medical imaging. This session focused on the Image Gently campaign, which is a multidisciplinary partnership focused on increasing awareness, developing education materials, and advocating for children to protect them from unnecessary radiation. Such protection is important because emerging data suggest that preadolescents and adolescents may be at increased risk for future malignancy if they are exposed to radiation from diagnostic imaging. Many health care practitioners may not understand how to decrease children's radiation exposure; the goals of Image Gently are to increase all stakeholders' understanding of these risks and to encourage radiation reduction strategies. Clearly, diagnostic imaging is an important and necessary tool for certain medical care. Image Gently advocates methods to reduce the use of unnecessary ionizing radiation by sharing best practices of imaging protocols for children and using alternative imaging that avoids ionizing radiation. This article summarizes our recent presentation on Image Gently to this workgroup: It focuses on the risks for preadolescents and adolescents and on strategies to minimize these risks.

The endothelium: influencing vascular smooth muscle in many ways

The endothelium, although only a single layer of cells lining the vascular and lymphatic systems, contributes in multiple ways to vascular homeostasis. Subsequent to the 1980 report by Robert Furchgott and John Zawadzki, there has been a phenomenal increase in our knowledge concerning the signalling molecules and pathways that regulate endothelial - vascular smooth muscle communication. It is now recognised that the endothelium is not only an important source of nitric oxide (NO), but also numerous other signalling molecules, including the putative endothelium-derived hyperpolarizing factor (EDHF), prostacyclin (PGI(2)), and hydrogen peroxide (H(2)O(2)), which have both vasodilator and vasoconstrictor properties. In addition, the endothelium, either via transferred chemical mediators, such as NO and PGI(2), and (or) low-resistance electrical coupling through myoendothelial gap junctions, modulates flow-mediated vasodilatation as well as influencing mitogenic activity, platelet aggregation, and neutrophil adhesion. Disruption of endothelial function is an early indicator of the development of vascular disease, and thus an important area for further research and identification of potentially new therapeutic targets. This review focuses on the signalling pathways that regulate endothelial - vascular smooth muscle communication and the mechanisms that initiate endothelial dysfunction, particularly with respect to diabetic vascular disease.

[What is a "poison"? Proposal of definition]

We discuss different interpretations of the term poison as well as the need of bringing up to date the changes in this matter according to the science progress. A clear and exact definition is proposed after analysing the factors that affect the relativity of the concept and its boundaries. The proposal for a definition is presented taking into account the most broadly extended concepts concerning its significance. That is to say: "a poison is, for human beings and their non-pathogenic and non-harmful biological environment, an electromagnetic or corpuscular radiation, or a non-infectious chemical agent, structured no larger in size than a small particle or fibre that, after being generated internally or after contact, penetration and/or absorption by a live organism, in sufficiently high dose, can produce or produces a direct or indirect adverse effect unrelated to its temperature or measurable electrical potential difference". The scientific knowledge needs accurate definitions to avoid ambiguities.

Collection of biological samples in forensic toxicology

Forensic toxicology is the study and practice of the application of toxicology to the purposes of the law. The relevance of any finding is determined, in the first instance, by the nature and integrity of the specimen(s) submitted for analysis. This means that there are several specific challenges to select and collect specimens for ante-mortem and post-mortem toxicology investigation. Post-mortem specimens may be numerous and can endow some special difficulties compared to clinical specimens, namely those resulting from autolytic and putrefactive changes. Storage stability is also an important issue to be considered during the pre-analytic phase, since its consideration should facilitate the assessment of sample quality and the analytical result obtained from that sample. The knowledge on degradation mechanisms and methods to increase storage stability may enable the forensic toxicologist to circumvent possible difficulties. Therefore, advantages and limitations of specimen preservation procedures are thoroughfully discussed in this review. Presently, harmonized protocols for sampling in suspected intoxications would have obvious utility. In the present article an overview is given on sampling procedures for routinely collected specimens as well as on alternative specimens that may provide additional information on the route and timing of exposure to a specific xenobiotic. Last, but not least, a discussion on possible bias that can influence the interpretation of toxicological results is provided. This comprehensive review article is intented as a significant help for forensic toxicologists to accomplish their frequently overwhelming mission.

Drugs of abuse: the highs and lows of altered mental states in the emergency department

The diagnosis and management of poisoned patients presenting with alterations in mental status can be challenging, as patients are often unable (or unwilling) to provide an adequate history. Several toxidromes exist. Recognition hinges upon vital signs and the physical examination. Understanding these "toxic syndromes" may guide early therapy and management, providing insight into the patient's underlying medical problem. Despite toxidrome recognition guiding antidotal therapy, the fundamental aspect of managing these patients involves meticulous supportive care. The authors begin with a discussion of various toxidromes and then delve into the drugs responsible for each syndrome. They conclude with a discussion on drug-facilitated sexual assault ("date rape"), which is both an underrecognized problem in the emergency department (ED) and representative of the drug-related problems faced in a modern ED.

Anticancer agents against malaria: time to revisit?

The emergence of artemisinin resistance could adversely impact the current strategy for malaria treatment; thus, new drugs are urgently needed. A possible approach to developing new antimalarials is to find new uses for old drugs. Some anticancer agents such as methotrexate and trimetrexate are active against malaria. However, they are commonly perceived to be toxic and thus not suitable for malaria treatment. In this opinion article, we examine how the toxicity of anticancer agents is just a matter of dose or ‘only dose makes the poison’, as coined in Paracelsus’ law. Thus, the opportunity exists to discover new antimalarials using the anticancer pharmacopoeia.

Bioassays for bomb-makers: proof of concept

Clandestine bomb-makers are exposed to significant amounts of explosives and allied materials. As with any ingested xenobiotic substance, these compounds are subject to biotransformation. As such, the potential exists that characteristic suites of biomarkers may be produced and deposited in matrices that can be exploited for forensic and investigative purposes. However, before such assays can be developed, foundational data must be gathered regarding the toxicokinetics, fate, and transport of the resulting biomarkers within the body and in matrices such as urine, hair, nails, sweat, feces, and saliva. This report presents an in vitro method for simulation of human metabolic transformations using human liver microsomes and an assay applicable to representative nitro-explosives. Control and metabolized samples of TNT, RDX, HMX, and tetryl were analyzed using high-performance liquid chromatography coupled to tandem mass spectrometry (LC/MS/MS) and biomarkers identified for each. The challenges associated with this method arise from solubility issues and limitations imposed by instrumentation, specifically, modes of ionization.

Monitoring gene changes during antiepileptic drug therapy to widen the safety window and reduce pharmacoresistance

A novel and potentially effective way to decrease pharmacoresistance is to widen an antiepileptic drug's (AED) safety window by altering its efficacy-toxicity relationship to reduce the frequency or eliminate the occurrence of drug-induced toxicities. The first step in this process is to identify specific AED toxicities that are common, objective, reliable to assess, and exhibit both interpatient and interdrug variability. Next, one or more of the fundamental sources of biological variability (e.g., DNA, RNA, proteins, or metabolites) is selected for study. By identifying a relationship between variations in these fundamental sources and specific AED toxicities, one aims to identify pathways underlying the genesis of the toxicity (mechanisms) or biomarkers related to elevated risk for AED toxicity (predictors). These types of studies have many methodological challenges. However, if properly conducted, the resulting data could be used to design interventions that directly block the toxicity mechanisms or preselect individuals who are at high risk of developing these toxicities. Both approaches would conceivably widen the safety window of efficacious AEDs and reduce the incidence of pharmacoresistance. This article describes a general framework for this approach and provides an example of the methodology using differential gene expression measured using RNA-based microarray technology in children experiencing VPA-associated weight gain.