Effects of concomitant use of THC and irinotecan on tumour growth and biochemical markers in a syngeneic mouse model of colon cancer.

Clinical treatment with the antineoplastic drug irinotecan (IRI) is often hindered by side effects that significantly reduce the quality of life of treated patients. Due to the growing public support for products with Δ9-tetrahydrocannabinol (THC), even though relevant scientific literature does not provide clear evidence of their high antitumour potential, some cancer patients take unregistered preparations containing up to 80 % THC. This study was conducted on a syngeneic colorectal cancer mouse model to test the efficiency and safety of concomitant treatment with IRI and THC. Male BALB/c mice subcutaneously injected with CT26 cells were receiving 60 mg/kg of IRI intraperitoneally on day 1 and 5 of treatment and/or 7 mg/kg of THC by gavage a day for 7 days. Treatment responses were evaluated based on changes in body, brain, and liver weight, tumour growth, blood cholinesterase activity, and oxidative stress parameters. Irinotecan's systemic toxicity was evidenced by weight loss and high oxidative stress. The important finding of this study is that combining THC with IRI diminishes IRI efficiency in inhibiting tumour growth. However, further studies, focused on more subtle molecular methods in tumour tissue and analytical analysis of IRI and THC distribution in tumour-bearing mice, are needed to prove our observations.

The effects of ketamine on viability, primary DNA damage, and oxidative stress parameters in HepG2 and SH-SY5Y cells.

Ketamine is a dissociative anaesthetic used to induce general anaesthesia in humans and laboratory animals. Due to its hallucinogenic and dissociative effects, it is also used as a recreational drug. Anaesthetic agents can cause toxic effects at the cellular level and affect cell survival, induce DNA damage, and cause oxidant/antioxidant imbalance. The aim of this study was to explore these possible adverse effects of ketamine on hepatocellular HepG2 and neuroblastoma SH-SY5Y cells after 24-hour exposure to a concentration range covering concentrations used in analgesia, drug abuse, and anaesthesia (0.39, 1.56, and 6.25 µmol/L, respectively). At these concentrations ketamine had relatively low toxic outcomes, as it lowered HepG2 and SH-SY5Y cell viability up to 30 %, and low, potentially repairable DNA damage. Interestingly, the levels of reactive oxygen species (ROS), malondialdehyde (MDA), and glutathione (GSH) remained unchanged in both cell lines. On the other hand, oxidative stress markers [superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT)] pointed to ketamine-induced oxidant/antioxidant imbalance.

Cytotoxic, genotoxic, and oxidative stress-related effects of lysergic acid diethylamide (LSD) and phencyclidine (PCP) in the human neuroblastoma SH-SY5Y cell line.

Lysergic acid diethylamide (LSD) is a classic hallucinogen, widely abused for decades, while phencyclidine (PCP) has increased in popularity in recent years, especially among the adolescents. Very little is known about the general toxicity of these compounds, especially about their possible neurotoxic effects at the cell level. The aim of this study was to address these gaps by assessing the toxic effects of 24-hour exposure to LSD and PCP in the concentration range of 0.39-100 µmol/L in the human neuroblastoma SH-SY5Y cell line. After cell viability was established, cells treated with concentrations that reduced their viability up to 30 % were further subjected to the alkaline comet assay and biochemical assays that enable estimation of oxidative stress-related effects. Treatment with LSD at 6.25 µmol/L and with PCP at 3.13 µmol/L resulted with 88.06±2.05 and 84.17±3.19 % of viable cells, respectively, and led to a significant increase in primary DNA damage compared to negative control. LSD also caused a significant increase in malondialdehyde level, reactive oxygen species (ROS) production, and glutathione (GSH) level, PCP significantly increased ROS but lowered GSH compared to control. Treatment with LSD significantly increased the activities of all antioxidant enzymes, while PCP treatment significantly increased superoxide dismutase (SOD) and glutathione peroxidase (GPx) but decreased catalase (CAT) activity compared to control. Our findings suggest that LSD has a greater DNA damaging potential and stronger oxidative activity than PCP in SH-SY5Y cells.

Food defence systems as an answer to food terrorism.

Terrorist attacks on critical infrastructures can cause problems to a national stability and functioning. Food and water supply chains are some of the most important infrastructures, and it is the country's (government's) obligation to provide sufficient quantities of food and water to its population. Intentional food contamination can, among other motives, originate from an act of terrorism (with political or ideological motives) with the aim of causing fear (terror) among people. Food defence systems can help assess vulnerabilities, determine mitigation strategies for terrorist attack, estimate risks, and prevent a terrorist attack. Risk assessment and prevention also include control over the production and distribution of potential chemical, biological, radiological or nuclear (CBRN) agents or their related materials. When a terrorist attack occurs, rapid and organised response is essential in terms of determining the type of agent used, managing the diseased, ensuring the functioning of the food and water supply, and the recovery of the infrastructure system under attack. Food defence planning as part of a food counterterrorism strategy should include considerations regarding the global food market and the fact that ingredients are supplied from all over the world (vendor certificates). Preventing terrorist attacks on sources of food and water is a far better option than crisis management once an attack had already been committed, but governments should have a response to any scenario.

Optimisation of a gas chromatography-mass spectrometry method for the simultaneous determination of tetrahydrocannabinol and its metabolites in rat urine.

In order to evaluate the effect of irinotecan (IRI) on urinary elimination of delta-9-tetrahydrocannabinol (THC) in a rat experimental model, we developed an analytical method for the determination of the mass concentration of THC and its metabolites [11-hydroxy-delta-9-tetrahydrocannabinol (THC-OH) and 11-nor-9-carboxy-delta-9-tetrahydrocannabinol (THC-COOH)] in the urine of rats treated only with THC and treated simultaneously with THC and irinotecan. For this purpose, hydrolysis and solid phase extraction conditions of the investigated analytes were optimised and a gas chromatography-mass spectrometry (GC-MS) method was developed to determine all three analytes in rat urine. The most effective hydrolysis method for THC, THC-OH, and THC-COOH conjugates was so-called tandem hydrolysis by the ß-glucuronidase enzyme from Escherichia coli at 50 °C for 2 hours and followed by alkaline hydrolysis. The proposed method was then applied for determining concentrations of analytes in 24-hour rat urine. THC was not detected in either sample, THC-OH was detected in 50 % of samples, and THC-COOH in all of the samples. Enhanced urinary THC-COOH excretion was noted in rats administered combined treatment compared to single THC treatment. The method described herein was suitable for determining the mass concentration of THC metabolites in the rat urine due to its sensitivity (detection limits: 0.8-1.0 µg/L), accuracy (>96 %), and precision (RSD <6 %).

Imidacloprid as reproductive toxicant and endocrine disruptor: investigations in laboratory animals.

Imidacloprid, a neonicotinoid insecticide, has been used worldwide due to its selective toxicity for insects. Its residues may enter the food chain, which is why it is important to investigate the potential adverse effects of imidacloprid exposure. This review summarises current knowledge of the reproductive toxicity and disruptive endocrine effects of imidacloprid in laboratory animals. Investigations, conducted mostly on laboratory rats, have shown adverse effects of imidacloprid on the reproductive ability in both parental and offspring generation as well as on the development of the offspring. Like many pesticides, imidacloprid may also act as endocrine disrupting chemical (EDC). It may disrupt the metabolic homeostasis, contribute to obesity, and disrupt steroidogenesis by inhibiting cytochrome P450 (CYP) enzyme activities. All these adverse effects of imidacloprid may pose a serious risk for reproduction and development with long-term consequences in adulthood.

Levels of polychlorinated biphenyls in human milk samples in European countries.

Polychlorinated biphenyls (PCBs) are persistent pollutants, harmful to human health, which enter the human body mainly through food and bind to body fat. For these reasons their use in most countries is prohibited. Human milk has an advantage over other types of human samples in measuring human exposure to PCBs, as it is obtained with non-invasive sampling methods. In Europe, including Croatia, PCB levels have been monitored for many years. This review summarises PCB trends in human milk across Europe. The trend is generally downward, with higher levels prevailing in urban areas near industrial plants. The highest PCB levels were reported in the Czech Republic and Slovakia.

Facts about phthalate toxicity in humans and their occurrence in alcoholic beverages.

Phthalates are esters of phthalic acid and aliphatic alcohol added to plastic to improve its softness, flexibility, and extensibility. They easily migrate from plastic products into the environment because of their physical and chemical properties. This review summarises their characteristics, distribution in the environment, monitoring, use, toxic effects on human health, regulatory limits in different matrices and products, and tolerable daily intake. The studies we have reviewed suggest that phthalates have a potential to affect reproduction and development in humans. Due to the inconsistent data, further studies are needed and, in the meantime, precautionary policies must be implemented. Here we draw attention to the methods of determining phthalate levels in alcoholic beverages and reported levels in plum spirits produced in Croatia. Legally produced and moderately consumed plum spirits do not seem to increase the risk of phthalate toxicity for human health. We conclude with recommendations for the effective monitoring of phthalate exposure in humans and for the implementation of alternative materials in alcohol production.

In vitro assessment of the cytotoxic, DNA damaging, and cytogenetic effects of hydroquinone in human peripheral blood lymphocytes.

This study investigated the mechanisms of hydroquinone toxicity and assessed the relationships between its cytotoxic, genotoxic, and cytogenetic effects tested at 8, 140, and 280 µg mL-1 in human peripheral blood lymphocytes exposed for 24 h. The outcomes of the treatments were evaluated using the apoptosis/necrosis assay, the alkaline comet assay, and the cytokinesis-block micronucleus (CBMN) cytome assay. The tested hydroquinone concentrations produced relatively weak cytotoxicity in resting lymphocytes, which mostly died via apoptosis. Hydroquinone's marked genotoxic effects were detected using the alkaline comet assay. Significantly decreased values of all comet parameters compared to controls indicated specific mechanisms of hydroquinone-DNA interactions. Our results suggest that the two higher hydroquinone concentrations possibly led to cross-linking and adduct formation. Increased levels of DNA breakage measured following exposure to the lowest concentration suggested mechanisms related to oxidative stress and inhibition of topoisomerase II. At 8 µg mL-1, hydroquinone did not significantly affect MN formation. At 140 and 280 µg mL-1, it completely blocked lymphocyte division. The two latter concentrations also led to erythrocyte stabilization and prevented their lysis. At least two facts contribute to this study's relevance: (I) this is the first study that quantifies the degree of reduction in total comet area measured in lymphocyte DNA after hydroquinone treatment, (II) it is also the first one on a lymphocyte model that adopted the "cytome" protocol in an MN assay and found that lymphocytes exposure even to low hydroquinone concentration resulted in a significant increase of nuclear bud frequency. Considering the limitations of the lymphocyte model, which does not possess intrinsic metabolic activation, in order to unequivocally prove the obtained results further studies using other appropriate cell lines are advised.

Evaluation of Urinary Btex, Nicotine, and Cotinine as Biomarkers of Airborne Pollutants in Nonsmokers and Smokers.

Benzene, toluene, ethylbenzene, and isomeric xylenes (BTEX) are by-products of tobacco smoke and traffic emissions. The aim of this study was to determine the contribution of cigarette smoking to urinary levels of BTEX present in humans. Nicotine and cotinine, biomarkers of exposure to tobacco smoke, as well as BTEX, were measured in urine of smokers (n = 70) and nonsmokers (n = 65) using headspace solid-phase microextraction (HS-SPME) followed by gas chromatography-mass spectrometry (GC-MS). In smokers, a significant correlation was found between urinary BTEX levels and nicotine and cotinine. In addition, significant regression models with nicotine and cotinine as predictors showed that BTEX in smokers' urine was predominantly derived from exposure to tobacco smoke. In nonsmokers a weak correlation between BTEX and nicotine and cotinine was found in urine. Further, there was a lack of significant contribution of BTEX to urinary nicotine and cotinine concentrations in nonsmokers. Thus, it was presumed that vehicle exhaust was the main source of exposure to BTEX in nonsmokers.

Quantitative analysis of arbutin and hydroquinone in strawberry tree (Arbutus unedo L., Ericaceae) leaves by gas chromatography-mass spectrometry.

The phenolic glycoside arbutin and its metabolite with uroantiseptic activity hydroquinone occur naturally in the leaves of various medicinal plants and spices. In this study, an extraction procedure coupled with gas chromatography-mass spectrometry (GC-MS) was developed to determine arbutin and hydroquinone content in strawberry tree (Arbutus unedo L., Ericaceae) leaves. The method showed good linearity (R2>0.9987) in the tested concentration range (0.5-200 µg mL(-1)), as well as good precision (RSD<5%), analytical recovery (96.2-98.0%), and sensitivity (limit of detection=0.009 and 0.004 µg mL(-1) for arbutin and hydroquinone, respectively). The results obtained by the validated GC-MS method corresponded well to those obtained by high performance liquid chromatography (HPLC) method. The proposed method was then applied for determining arbutin and hydroquinone content in methanolic leaf extracts. The amount of arbutin in the leaves collected on the island of Kolocep (6.82 mg g(-1) dry weight) was found to be higher (tpaired=43.57, tc=2.92) in comparison to the amount of arbutin in the leaves collected on the island of Mali Losinj (2.75 mg g(-1) dry weight). Hydroquinone was not detected in any of the samples. The analytical features of the proposed GC-MS method demonstrated that arbutin and hydroquinone could be determined alternatively by gas chromatography. Due to its wide concentration range, the method could also be suitable for arbutin and hydroquinone analysis in leaves of other plant families (Rosaceae, Lamiaceae, etc.).

Tobacco smoke and pregnancy: segmental analysis of nicotine in maternal hair.

The investigation assessed nicotine metabolism prior to and during pregnancy in relation to different maternal smoking habits. It included segmental hair analysis in 3 groups of postpartum women: 32 active smokers, 35 passive smokers, and 19 unexposed nonsmokers. Maternal hair at least 12 cm long was collected after delivery and was divided into four 3-cm-long segments representing each trimester of pregnancy and the 3 months prior to pregnancy. Hair nicotine concentration was determined by gas chromatography-mass spectrometry. Nicotine levels were the highest in the 3-month period before pregnancy and it gradually decreased with advancing gestation in all study groups. These results suggest that when assessing tobacco exposure as measured by nicotine in hair, metabolic changes of nicotine during pregnancy should be taken into consideration.

Immunomodulation of cell-mediated cytotoxicity after chronic exposure to vapors.

Cytotoxic T lymphocytes and natural killer (NK) cells represent two major types of immune cytotoxic cells that have a crucial role in innate immunity. Urban air pollution represents a common and difficult problem in the majority of metropolises, which contain high levels of traffic congestion generating great amounts of genotoxic substances. Diesel exhaust particles act as adjuvant in the immune response and may lead to the enhancement of proinflammatory and proallergic response without exposure to allergen. The activities of diesel exhaust particles (DEPs) and their benzene extracts may cause the increasing respiratory mortality and morbidity. Since the lung inflammatory response to DEPs is compartmentalized, the importance of finding the suppressive substances, whose function will be to elucidate the DEPs effects, is fundamental. The objectives of this study were to examine the NK-mediated cytotoxicity against human NK-sensitive target, as well as the values of BTEX (benzene, toluene, ethylbenzene and xylene isomers) in urine in people from industrial area and those from rural fields. NK-mediated cytotoxicity of peripheral blood mononuclear cells was investigated against human NK-sensitive K-562 tumor cell line. BTEX were analyzed from urine by a HS-SPME method. All exposed individuals were demonstrated the significant decreased of NK-mediated cytotoxicity against human NK-sensitive target and increasing BTEX values. BTEX-analyze in urine and determination of NK-mediated cytotoxicity, as an important methods represent good markers in environmental monitoring, which contribute to the better protection of air pollutants and quicker diagnosis of environmental diseases.

Facts about nicotine toxicity.

Nicotine is an alkaloid obtained from the leaves of the tobacco plant, and it is the main constituent of tobacco smoke. This review opens with physical and chemical properties of nicotine and with general considerations about the methods for determining nicotine and its metabolite cotinine. It summarises the data about acute and long-term toxicity of nicotine and also reviews its metabolism and kinetic data, types of exposure and the main recognised health effects, with special attention to reproductive, cardiovascular, pulmonary, gastrointestinal, immunological and genetic toxicity. The main focus is on hazardous exposure and risk estimation.