Reference Dose Research Articles

Investigating the individual and mixture cytotoxicity of co-occurring aflatoxin B1, enniatin B, and sterigmatocystin on gastric, intestinal, hepatic, and renal cellular models

This study investigates the individual and combined effects of the mycotoxins, Aflatoxin B1 (AFB1), Enniatin B (ENNB) and Sterigmatocystin (STG), on the cellular viability of gastric (NCI–N87), intestinal (Caco-2), hepatic (Hep-G2) and renal (Hek-293) cells, shedding light on synergistic or antagonistic effects using a constant ratio combination design proposed by Chou-Talalay. These toxins are prevalent in cereal-based foods, frequently consumed by children which raises concerns about their exposure to these mycotoxins. This population is particularly vulnerable to the effects of these toxins due to their underdeveloped organs and incompletely structured physiological processes. Results showed that ENB was the most toxic of the three mycotoxins across all cell lines, while STG and AFB1 showed lower toxicity. The combination of ENNB + STG was found to be the most potent in terms of binary mixtures. In regard to ternary combinations, Caco-2 cells are more sensitive to the tested mycotoxins, whereas NCI–N87 cells show lower levels of cell damage. Worrying dose reduction values (>10-fold) were found for ENNB in binary and ternary combinations at low exposure levels. These findings are significant for establishing initial reference values, which play a pivotal role in estimating reference doses that are subsequently incorporated into the broader risk assessment process.

Nano-CeO2 activates physical and chemical defenses of garlic (Allium sativum L.) for reducing antibiotic resistance genes in plant endosphere

The transmission of manure- and wastewater-borne antibiotic-resistant bacteria (ARB) to plants contributes to the proliferation of antimicrobial resistance in agriculture, necessitating effective strategies for preventing the spread of antibiotic resistance genes (ARGs) from ARB in the environment to humans. Nanomaterials are potential candidates for efficiently controlling the dissemination of ARGs. The present study investigated the abundance of ARGs in hydroponically grown garlic (Allium sativum L.) following nano-CeO2 (nCeO2) application. Specifically, root exposure to nCeO2 (1, 2.5, 5, 10 mg L−1, 18 days) reduced ARG abundance in the endosphere of bulbs and leaves. The accumulation of ARGs (cat, tet, and aph(3’)-Ia) in garlic bulbs decreased by 24.2–32.5 % after nCeO2 exposure at 10 mg L−1. Notably, the lignification extent of garlic stem-disc was enhanced by 10 mg L−1 nCeO2, thereby accelerating the formation of an apoplastic barrier to impede the upward transfer of ARG-harboring bacteria to garlic bulbs. Besides, nCeO2 upregulated the gene expression related to alliin biosynthesis and increased allicin content by 15.9–16.2 %, promoting a potent antimicrobial defense for reducing ARG-harboring bacteria. The potential exposure risks associated with ARGs and Ce were evaluated according to the estimated daily intake (EDI). The EDI of ARGs exhibited a decrease exceeding 95 %, while the EDI of Ce remained below the estimated oral reference dose. Consequently, through stimulating physical and chemical defenses, nCeO2 contributed to a reduced EDI of ARGs and Ce, highlighting its potential for controlling ARGs in plant endosphere within the framework of nano-enabled agrotechnology.

Nationwide distribution of perfluoroalkyl ether carboxylic acids in Chinese diets: An emerging concern

With the phase-out of perfluorooctanoic acid (PFOA) and its replacement by perfluoroalkyl ether carboxylic acids (PFECAs), there is a potential for increased exposure to various new PFECAs among the general population in China. While there are existing studies on dietary exposure to legacy perfluoroalkyl and polyfluoroalkyl substances (PFASs), research on dietary exposure to PFECAs, especially among the general Chinese populace, remains scarce. In the present study, we investigated the distribution of PFECAs in dietary sources from 33 cities across five major regions in China, along with the associated dietary intake. Analysis indicated that aquatic animal samples contained higher concentrations of legacy PFASs compared to those from terrestrial animals and plants. In contrast, PFECAs were found in higher concentrations in plant and terrestrial animal samples. Notably, hexafluoropropylene oxide dimer (HFPO-DA) was identified as the dominant compound in vegetables, cereals, pork, and mutton across the five regions, suggesting widespread dietary exposure. PFECAs constituted the majority of PFAS intake (57 %), with the estimated daily intake (EDI) of HFPO-DA ranging from 2.33 to 3.96 ng/kg bw/day, which corresponds to 0.78–1.32 times the reference dose (RfD) (3.0 ng/kg bw/day) set by the United States Environmental Protection Agency. Given the ubiquity of HFPO-DA and many other PFECAs in the nationwide diet of China, there is an urgent need for further research into these chemicals to establish relevant safety benchmarks or consumption advisory values for the diet.

Investigation on Individual Variation of Organ Doses for Photon External Exposures: A Monte Carlo Simulation Study

Background: The reference dose coefficients (DCs) of the International Commission on Radiological Protection (ICRP) have been widely used to estimate organ doses of individuals for risk assessments. This approach has been well accepted because individual anatomy data are usually unavailable, although dosimetric uncertainty exists due to the anatomical difference between the reference phantoms and the individuals. We attempted to quantify the individual variation of organ doses for photon external exposures by calculating and comparing organ DCs for 30 individuals against the ICRP reference DCs.Materials and Methods: We acquired computed tomography images from 30 patients in which eight organs (brain, breasts, liver, lungs, skeleton, skin, stomach, and urinary bladder) were segmented using the ImageJ software to create voxel phantoms. The phantoms were implemented into the Monte Carlo N-Particle 6 (MCNP6) code and then irradiated by broad parallel photon beams (10 keV to 10 MeV) at four directions (antero-posterior, postero-anterior, left-lateral, right-lateral) to calculate organ DCsResults and Discussion: There was significant variation in organ doses due to the difference in anatomy among the individuals, especially in the kilovoltage region (e.g., <100 keV). For example, the red bone marrow doses at 0.01 MeV varied from 3 to 7 orders of the magnitude depending on the irradiation geometry. In contrast, in the megavoltage region (1–10 MeV), the individual variation of the organ doses was found to be negligibly small (differences <10%). It was also interesting to observe that the organ doses of the ICRP reference phantoms showed good agreement with the mean values of the organ doses among the patients in many casesConclusion: The results of this study would be informative to improve insights in individualspecific dosimetry. It should be extended to further studies in terms of many different aspects (e.g., other particles such as neutrons, other exposures such as internal exposures, and a larger number of individuals/patients) in the future.

Traditional and Domestic Cooking Dramatically Reduce Estrogenic Isoflavones in Soy Foods.

Soybean is a pulse which has considerable nutritional value due to its high protein, fibers and polyunsaturated fatty acid (PUFA) contents. It also contains phytoestrogenic compounds that definitely hinder its recommendation for general consumption. Contrary to ancient times, when soybeans were boiled, modern commercial soy foods can contain up to 150 mg/100g of estrogenic isoflavones. Interestingly, current estimations of isoflavone intake in the literature do not distinguish between the origins of soy food, i.e., whether it is homemade or commercial. As a result, the isoflavone exposure in Asian countries may well be overestimated. This study aims to demonstrate, based on step-by-step monitoring of isoflavones, that traditional and domestic treatments, leveraging isoflavones water-solubility, can indeed significantly reduce their content in soy foods. Indeed, when compared to commercial foods, the isoflavone content was found to be 20, 2.6, 4.5 and 9.8 times lower in "homemade" soy juice, tofu, tempeh and miso, respectively. Additionally, water soaking was found to reduce the isoflavones levels in soy-textured proteins by more than 70%. Hence, this simple process has the potential to help drastically reduce overall xenoestrogens exposure. This study could serve as a basis for establishing the isoflavones Reference Dose and issuing food safety guidelines.

Exposure of Male Farmers and Nonfarmers to Neonicotinoid Pesticides in the South-West and Littoral Regions of Cameroon: A Comparative Study.

Pesticides, especially the newly developed neonicotinoids, are increasingly used in many countries around the world, including Cameroon, to control pests involved in crop destruction or disease transmission. Unfortunately, the pesticides also pose tremendous environmental problems because a predominant amount of their residues enter environmental matrices to affect other nontargeted species including humans. This therefore calls for continuous biomonitoring of these insecticides in human populations. The present study sought to assess the neonicotinoid insecticide exposures in two agrarian regions of Cameroon, the South-West region and Littoral region. The study involved 188 men, including 125 farmers and 63 nonfarmers. Spot urine samples were obtained from these subjects and subjected to liquid chromatographic-tandem mass spectrometric analysis for concentrations of neonicotinoid compounds, including acetamiprid, clothianidin, dinotefuran, imidacloprid, thiacloprid, nitenpyram, thiamethoxam, and N-dm-acetamiprid. Neonicotinoid compounds were detected in all study participants, and residues of all the screened pesticides were detected among participants. N-dm-Acetamiprid and imidacloprid were the most prevalent among the subjects (100.0% and 93.1%, respectively), whereas nitenpyram was less common (3.2%). The median values of imidacloprid and total urinary neonicotinoid concentrations were elevated among farmers (0.258 vs. 0.126 µg/L and 0.829 vs. 0.312 µg/L, respectively). Altogether the findings showed that both the farmer and nonfarmer study populations of Cameroon were exposed to multiple residues of neonicotinoids, with relatively higher levels of pesticides generally recorded among farmers. Although exposure levels of the neonicotinoids were generally lower than their respective reference doses, these results warrant further research on the health risk evaluation of multiple residues of the pesticides and reinforcement of control measures to minimize the exposure risks, especially among farmers. Environ Toxicol Chem 2024;43:952-964. © 2024 SETAC.

Assessing malathion residue impact on poultry health, human safety, and production performance

Over the past decade, food safety has become a major concern due to the intensive use of pesticides. Pesticide contamination has been observed in poultry products when seeds are coated with pesticides or when stored products are exposed to pesticides in warehouses. In this experiment, the residue levels of malathion transferred from corn grain to the different parts of the chicken product, its transfer factors (TFs) and the human dietary risk for consumers were evaluated. Growth performance and carcass parameters of the chicken samples were also determined after different doses of malathion exposure. Malathion residues from different parts of chicken meat (breast, thigh, wing, liver and skin) were extracted by the QuEChERS method and analyzed by liquid chromatography-mass spectrophotometry (LC-MS/MS). A deterministic approach was used to calculate the acute and chronic risk assessment. Body weight, feed conversion ratio and feed intake decreased with increasing malathion dose. In addition to reduced feed intake, cold carcass and liver weights of the chicks were also decreased. The highest residues were found in the skin of the chicken followed by the breast, thigh, wing and liver. The TFs of malathion varied between 0.00 and 0.05 according to the different doses applied (4 mg/kg, 8 mg/kg, 16 mg/kg, 32 mg/kg). The chronic exposure assessment (HQ) showed that consumers of all ages and genders consumed 0.008–0.604% of the acceptable daily intake (0.3 mg/kg body weight (bw)/day) of malathion from chicken products. The acute intake assessment (aHQ) of consumers ranged from 0.00015 to 0.0135% of the acute reference dose (0.3 mg/kg bw). In conclusion the results suggest that the risk associated with the malathion residues in chicken meat was found to be low but the residue levels in meat should not be ignored.

Accumulation of potentially toxic elements in fourfinger threadfin (Eleutheronema tetradactylum) and black pomfret (Parastromateus niger) from Selangor, Malaysia.

The accumulation of potentially toxic elements (PTEs) has raised public awareness due to harmful contamination to both human and marine creatures. This study was designed to determine the concentration of copper (Cu), zinc (Zn), cadmium (Cd), and nickel (Ni) in the intestine, kidney, muscle, gill, and liver tissues of local commercial edible fish, fourfinger threadfin (Eleutheronema tetradactylum), and black pomfret (Parastromateus niger) collected from Morib (M) and Kuala Selangor (KS). Among the studied PTEs, Cu and Zn were essential elements to regulate body metabolism with certain dosages required while Cd and Ni were considered as non-essential elements that posed chronic and carcinogenic risk. The concentration of PTEs in fish tissue samples was analyzed using flame atomic absorption spectrometry (F-AAS). By comparing the concentration of PTEs in fish tissues as a bioindicator, the environmental risk of Morib was more serious than Kuala Selangor because both fish species collected from Morib resulted in a higher PTEs concentration. For an average 62kg adult with a fish ingestion rate (FIR) of 0.16kg/person/day in Malaysia, the estimated weekly intake (EWI) of Cd from the consumption of E. tetradactylum (M: 0.0135mg/kg; KS: 0.0134mg/kg) and P. niger (M: 0.0140mg/kg; KS: 0.0132mg/kg) had exceeded the provisional tolerable weekly intake (Cd: 0.007mg/kg) established by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) and oral reference dose (ORD) values of Cd (0.001mg/kg/day) as provided by the United States Environmental Protection Agency (USEPA) regional screening level, thus it posed chronic risks for daily basis consumption. Besides, the value of the carcinogenic risk of Cd (0.7-3 to 0.8-3) and Ni (0.5-3 to 0.6-3) were in between the acceptable range (10-6 to 10-4) of the health index that indicates a relatively low possibility cancer occurrence to the consumers in both Morib and Kuala Selangor. This study recommended FIR to be 0.80kg/person/day to reduce the possibility of posing chronic and carcinogenic risks while at the same time obtaining the essential nutrients from the fish.

Evaluation of food allergen information, labelling and unintended food allergen presence in imported prepacked foods and drinks purchased online in the UK

Consumers have wide access to global food and drink products online and in store that require food allergen information and labelling. Frequent food and drink product recalls occur UK and worldwide due to incorrect labelling of food allergens and their unintended or undeclared presence. This research aims to evaluate the accuracy and compliance of information and labelling of substances or products causing allergies or intolerances in prepacked food and drink products imported from Asia and purchased online in the UK. The current study assessed 768 randomly selected prepacked products classified into 16 separate product categories, representative of items from 12 countries in Asia, sourced from 8 UK retailers. When screened for precautionary allergen labelling (PAL), 173 (22.5%) items provided PAL, with 24 phrasings being identified. Upon comparing food allergen information on pack and online, 36 products (36.0%) transferred inconsistencies on pack to online pages and 15 (15.0%) were not consistent. Additionally, laboratory studies were performed to detect milk and peanut allergens in a sub-group of 77 products. Following analysis, 24 (31.2%) contained unintended food allergens, with levels ranging from 0.2 to 6780.0 mg/kg. Of these items, 9 products (37.5%) had a risk ratio ≥ 1 exceeding action levels produced with the VITAL® 3.0 ED01 reference doses, recommending PAL, though 7 (29.2%) were found without PAL. A further 10 products (13.0%) overused PAL and 2 products (2.6%) used PAL correctly. This research indicates further refinement of policies to ensure adequate, accurate, clear and current food allergen information and labelling of products.

An evaluation of ankle and foot bolus in paediatric modulated arc total body irradiation (MATBI).

This retrospective planning study aimed to evaluate the role of bolus in achieving dose uniformity in the ankles and feet in paediatric patients undergoing Modulated Arc Total Body Irradiation (MATBI) treatment and to identify patient factors that may negate or warrant its use. The clinically treated plans of 20 paediatric patients who received MATBI treatment utilising ankle and foot bolus (Bolus plan) were compared with two retrospectively generated plans; a plan with bolus removed and no re-optimisation (No Bolus plan), and a re-optimised plan without bolus attempting to achieve equal dosimetry to the clinical plan via monitor unit adjustment (MU plan). Descriptive statistics were used to evaluate the dose uniformity criteria of ±10% coverage of the reference dose (RD) for each subregion of the ankle and foot for the three plans. The impact of patient height, weight, and age at the time of treatment was evaluated using Spearman's correlation. Variation in doses >10% RD was minimal across the three plans, with an average D1cc difference < 0.4Gy. For the ankle and foot regions in the Bolus plans, the volume receiving at least 90% of the RD (V90) was on average > 92%. In No Bolus and MU plans, there was an average reduction of 24.5% and 23.2% V90 coverage respectively in the toes. Spearman's correlation suggests height has the strongest relationship to D1cc. This study validated the continued use of ankle and foot bolus to achieve dosimetric goals for paediatric MATBI treatments, particularly V90 coverage across all heights.

Potential for the development of Taraxacum mongolicum aqueous extract as a phytogenic feed additive for poultry.

Taraxacum mongolicum (TM) is a kind of medicinal and edible homologous plant which is included in the catalogue of feed raw materials in China. It is rich in polyphenols, flavonoids, polysaccharides and other active substances, and shows many benefits to livestock, poultry and aquatic products. The study aimed to assess the potential of TM aqueous extract (TMAE) as a substitute for poultry AGPs. A total of 240 one-day-old Arbor Acker broilers were randomly assigned to four groups and fed a basal diet (Con) supplemented with 500, 1000, and 2000 mg/kg TMAE (Low, Medium, and High groups). The growth performance of the broilers was measured on day 21 and day 42. At the end of the trial, the researchers measured slaughter performance and collected serum, liver, spleen, ileum, and intestinal contents to investigate the effects of TMAE on serum biochemistry, antioxidant capacity, immune function, organ coefficient, intestinal morphology, flora composition, and short-chain fatty acids (SCFAs). The results showed that broilers treated with TMAE had a significantly higher average daily gain from 22 to 42 days old compared to the Con group. Various doses of TMAE resulted in different levels of improvement in serum chemistry. High doses increased serum alkaline phosphatase and decreased creatinine. TMAE also increased the antioxidant capacity of serum, liver, and ileum in broilers. Additionally, middle and high doses of TMAE enhanced the innate immune function of the liver (IL-10) and ileum (Occludin) in broilers. Compared to the control group, the TMAE treatment group exhibited an increase in the ratio of villi length to villi crypt in the duodenum. TMAE increased the abundance of beneficial bacteria, such as Alistipes and Lactobacillus, while reducing the accumulation of harmful bacteria, such as Colidextracter and Sellimonas. The cecum's SCFAs content increased with a medium dose of TMAE. Supplementing broiler diets with TMAE at varying doses enhanced growth performance and overall health. The most significant benefits were observed at a dose of 1000 mg/kg, including improved serum biochemical parameters, intestinal morphology, antioxidant capacity of the liver and ileum, immune function of the liver and ileum, and increased SCFAs content. Lactobacillus aviarius, norank_f_norank_o__Clostridia_UCG-014, and Flavonifractor are potentially dominant members of the intestinal microflora. In conclusion, TMAE is a promising poultry feed additive and 1000 mg/kg is an effective reference dose.

Predicting the error magnitude in patient-specific QA during radiotherapy based on ResNet.

The error magnitude is closely related to patient-specific dosimetry and plays an important role in evaluating the delivery of the radiotherapy plan in QA. No previous study has investigated the feasibility of deep learning to predict error magnitude. The purpose of this study was to predict the error magnitude of different delivery error types in radiotherapy based on ResNet. A total of 34 chest cancer plans (172 fields) of intensity-modulated radiation therapy (IMRT) from Eclipse were selected, of which 30 plans (151 fields) were used for model training and validation, and 4 plans including 21 fields were used for external testing. The collimator misalignment (COLL), monitor unit variation (MU), random multi-leaf collimator shift (MLCR), and systematic MLC shift (MLCS) were introduced. These dose distributions of portal dose predictions for the original plans were defined as the reference dose distribution (RDD), while those for the error-introduced plans were defined as the error-introduced dose distribution (EDD). Different inputs were used in the ResNet for predicting the error magnitude. In the test set, the accuracy of error type prediction based on the dose difference, gamma distribution, and RDD + EDD was 98.36%, 98.91%, and 100%, respectively; the root mean squared error (RMSE) was 1.45-1.54, 0.58-0.90, 0.32-0.36, and 0.15-0.24; the mean absolute error (MAE) was 1.06-1.18, 0.32-0.78, 0.25-0.27, and 0.11-0.18, respectively, for COLL, MU, MLCR and MLCS. In this study, error magnitude prediction models with dose difference, gamma distribution, and RDD + EDD are established based on ResNet. The accurate prediction of the error magnitude under different error types can provide reference for error analysis in patient-specific QA.

Neonicotinoid insecticides in waters of the northern Jiangsu segment of the Beijing-Hangzhou Grand Canal: Environmental and health implications

Neonicotinoid (NEO) insecticides have been frequently detected in natural aquatic environments. Nevertheless, the distribution of NEOs in artificial environments is not clear. The Beijing-Hangzhou Grand Canal is the longest canal in the world. The northern Jiangsu segment of the Grand Canal was selected to study the spatiotemporal variation and source of eight NEOs in the canal water and assess their ecological and health risks. The total NEO concentration in the canal water was 12–289 ng L−1 in the dry season and 18–373 ng L−1 in the wet season, which were within the concentration range in other 11 natural rivers worldwide. The average total NEO concentrations were not statistically different between the seasons; only the concentrations of imidaclothiz, thiacloprid (THI), acetamiprid, and dinotefuran were different. At city scale, the total NEO concentration in the dry season showed a decreasing trend along the water flow from Xuzhou City to Yangzhou City. The total NEO concentrations were found to be positively correlated with the sown area of farm crops and the rural labour force, indicating the agricultural influence on the spatial distribution of NEO concentrations. In the wet season, relatively high NEO concentrations were distributed in downstream sites under the influence of artificial regulation. The primary contributor to the NEO inputs into the canal was the nonpoint source in the dry and wet seasons, with a relative contribution of 68 %. THI, imidacloprid, clothianidin and thiamethoxan would produce chronic ecological risks in both seasons. Further consideration needs to be given to the above four NEOs and NEO mixtures. The human health risks that NEOs posed by drinking water were assessed based on the chronic daily intake (CDI). The maximum CDI for adults and children was lower than the reference doses. This suggested public health would not be at risk from canal water consumption.

Feasibility and Safety of Cone-Beam Computed Tomography Advanced Navigation to Optimize Intra-arterial Chemotherapy Infusion of Skull Base Tumors

Abstract Purpose To assess the feasibility and safety of cone-beam computed tomography (CBCT) advanced navigation for optimizing intra-arterial chemotherapy infusion (IACI) in patients with skull base tumors. Materials and Methods Retrospective review on 10 consecutive IACI procedures performed in five patients (four women, 1 man) over a 1-year period. The median age of the patients was 71 years (interquartile range: 34–74). During the procedures, a CBCT-based navigation software was employed to evaluate tumor perfusion and guide the infusion methods. Catheterization of the primary tumor feeding vessel was performed in seven cases when it originated from the external carotid artery, whereas a temporary balloon-assisted occlusion technique was utilized in the remaining three cases where the tumor was primarily fed by the internal carotid artery. Carboplatin, topotecan, and melphalan were injected over a 10-minute period. Fluoroscopy time, reference dose, and Kerma area product, which estimates effective dose, were analyzed. Results The technical success rate was 100%, with a median procedure length of 82 minutes (79–90). The median fluoroscopy time was 11.3 minutes (9.4–16.9), reference dose was 93.5 mGy (62–256.5), and Kerma area product was 11.6 Gy.cm2 (9.5–25.4). The median effective dose was 3.8 mSv (1.5–5.1). The median follow-up duration was 233.5 days (186.3–432). One severe adverse event was reported, involving a right brachial hematoma and brachiocephalic artery dissection related to catheterization through a type III aortic arch. Three patients exhibited disease progression, but two patients showed stable disease. Conclusion IACI for skull base tumors guided by CBCT navigation is both feasible and safe.

Lithium Content and Its Nutritional Beneficence, Dietary Intake, and Impact on Human Health in Edibles from the Romanian Market.

Lithium (Li) is present in human nutrition based on food intake, and several studies recommend it for treating mood disorders, even if the biological proprieties and biochemical mechanisms represent the basis for its use as an essential element. The Li content was evaluated using the inductively coupled plasma mass spectrometry technique (ICP-MS) in 1071 food and beverage samples from the Romanian market. The results show that Li had a decreasing mean concentration in the food samples as follows: vegetables leafy > bulbous > fructose > leguminous > egg whites > root vegetables > milk products > egg yolks > meats. Approximately a quarter of all data from each dataset category was extreme values (range between the third quartile and maximum value), with only 10% below the detection limit. Mean Li concentration indicated higher values in red wine, white wines, beers, and fruit juice and lower in ciders and bottled waters. A particular interest was addressed to plants for teas and coffee seeds, which showed narrow amounts of Li. For both food and beverages, two similar matrices, including egg whites and yolks and white and red wines, were found to have significant differences, which explains the high variability of Li uptake in various matrices. For 99.65% of the analyzed samples, the estimated daily intake of Li was below the provisional subchronic and chronic reference dose (2 µg/kgbw/day) for adverse effects in several organs and systems. Even so, a risk occurs in consuming bulbous vegetables (Li > 13.47 mg/kg) and fructose solano vegetables (Li > 11.33 mg/kg). The present study's findings indicate that ingesting most of the analyzed beverages and food samples could be considered safe, even if future studies regarding Li content, nutritional aspects, and human cohort diseases must be conducted.

Method development, validation, and risk assessment of multiple pesticide residues of fruits in China.

In this study, a muti-residue analysis method of 40 pesticides in five different categories of fruits in China was developed based on ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Five hundred real samples were analyzed and assessed for the dietary exposure risk. The sample treatment method was optimized by comparing four clean-up methods. The matrix effects of different fruits were evaluated. The analytical method was validated in terms of linearity, limit of detection (LOD), limit of quantification (LOQ), accuracy, and precision. The results showed that the optimal method was the treatment by clean up with ODS (octadecylsilane) and MgSO4. The matrix effect was the strongest in orange and weakest in apple. The LOD and LOQ of pesticides were 0.04-5.9 μg kg-1 and 0.13-19.5 μg kg-1, respectively. The recoveries at three spiked levels were ranged from 71.2 to 115.2% with the RSDs from 0.1 to 19.6%. Twenty-two pesticides were detected in 500 fruit samples fromthe major production regions of China, with concentrations ranging from 0.1 to 1930 μg kg-1. A total of 13, 10, 9, 8, and 4 pesticides were detected in peach, orange, grape, apple, and strawberry. Both the acceptable daily intake (ADI) and acute reference dose (ARfD) for all the detected pesticides were lower than 100%, indicating that the dietary intake risks are acceptable and would not pose potential health risks.

Equivalent uniform RBE-weighted dose in eye plaque brachytherapy.

Brachytherapy for ocular melanoma is based on the application of eye plaques with different spatial dose nonuniformity, time-dependent dose rates and relative biological effectiveness (RBE). We propose a parameter called the equivalent uniform RBE-weighted dose (EUDRBE) that can be used for quantitative characterization of integrated cell survival in radiotherapy modalities with the variable RBE, dose nonuniformity and dose rate. The EUDRBE is applied to brachytherapy with 125I eye plaques designed by the Collaborative Ocular Melanoma Study (COMS). The EUDRBE is defined as the uniform dose distribution with RBE=1 that causes equal cell survival for a given nonuniform dose distribution with the variable RBE>1. The EUDRBE can be used for comparison of cell survival for nonuniform dose distributions with different RBE, because they are compared to the reference dose with RBE=1. The EUDRBE is applied to brachytherapy with 125I COMS eye plaques that are characterized by a steep dose gradient in tumor base-apex direction, protracted irradiation during time intervals of 3-8 days, and variable dose-rate dependent RBE with a maximum of about 1.4. The simulations are based on dose of 85Gy prescribed to the farthest intraocular extent of the tumor (tumor apex). To compute the EUDRBE in eye plaque brachytherapy and correct for protracted irradiation, the distributions of physical dose have been converted to non-uniform distributions of biologically effective dose (BED) to include the biological effects of sublethal cellular repair, Our radiobiological analysis considers the combined effects of different time-dependent dose rates, spatial dose non-uniformity, dose fractionation and different RBE and can be used to derive optimized dose regimens brachytherapy. Our simulations show that the EUDRBE increases with the prescription depths and the maximum increase may achieve 6% for the tumor height of 12mm. This effect stems from a steep dose gradient within the tumor that increases with the prescription depth. The simulations also show that the EUDRBE increase may achieve 12% with increasing the dose rate when implant duration decreases. The combined effect of dose nonuniformity and dose rate may change the EUDRBE up to 18% for the same dose prescription of 85Gy to tumor apex. The absolute dose range of 48-61Gy (RBE) for the EUDRBE computed using 4 or 5 fractions is comparable to the dose prescriptions used in stereotactic body radiation therapy (SBRT) with megavoltage X-rays (RBE=1) for different cancers. The tumor control probabilities in SBRT and eye plaque brachytherapy are very similar at the level of 80% or higher that support the hypothesis that the selected approximations for the EUDRBE are valid. The computed range of the EUDRBE in 125I COMS eye plaque brachytherapy suggests that the selected models and hypotheses are acceptable. The EUDRBE can be useful for analysis of treatment outcomes and comparison of different dose regimens in eye plaque brachytherapy.

Assessment of the health risks associated with the consumption of bivalve mollusks potentially contaminated with phycotoxins from the coastal ecosystem of the Ebrié lagoon, Côte d'Ivoire.

This work focused on assessing of the risk associated with the consumption of bivalve mollusks, potentially contaminated with phycotoxins. The studied phycotoxins are saxitoxin (STX), okadaic acid (OA), dinophysistoxins (DTXs), yessotoxins (YTXs), pectenotoxins (PTX), azaspiracids (AZAs), and domoic acid (DA). These toxins were investigated in three species of bivalve mollusks (Anadara senilis, Crassostrea gasar, and Perna perna), originating from the Ebrié lagoon. Chemical analyses were carried out by LC-MS/MS, HPLC-FLD, and HPLC-UV. The level of OA and DTXs, STX, and DA was 10.92 µg OA eq./kg, 9.6 µg STX eq./kg, and 0.17 mg DA eq./kg, respectively. The level of PTXs and AZAs was 3.3 µg PTX-2 eq./kg and 13.86 µg AZA-1 eq./kg; that of YTXs was 0.01 mg YTX eq./kg. The daily exposure dose (DED) was 0.019 µg OA eq./kg bw for OA and DTXs; 0.285 µg DA eq./kg bw for DA; 0.006 µg PTX-2 eq./kg bw for PTXs; 0.016 µg STX eq./kg bw for STX; 0.01 µg YTX eq./kg bw for YTXs; and 0.024 µg AZA-1 eq./kg bw for AZAs for the oyster Crassostrea gasar. These estimated values are lower than the acute reference dose (ARfD) of each phycotoxin recommended by the European Food Safety Agency (EFSA). The risk of harmful effects is acceptable. The absence of risk is valid only for the study period (11 months) and concerns coastal populations living near the sampling points.

Dosimetric Comparison of Isodose Surface Volume and Total Reference Air Kerma (TRAK) based Volume in Cervical Cancer Brachytherapy.

We aim to compare TRAK & TPS based isodose volumes in cervical cancer brachytherapy and assess the feasibility, accuracy and potential future implications of TRAK in this regard and as a newer emerging tool to assess treatment intensity in cervical cancer brachytherapy. one hundred patients with histologically proven squamous cell carcinoma of cervix uteri were assessed for brachytherapy (after completion of external radiation) and prospectively enrolled for the study. 60 Gy, 75 Gy, and 85 Gy isodose volumes were obtained from the TPS (VTPS) for 50, 25 & 25 patients with Manchester, Fletcher & interstitial implant respectively, receiving various fractionation schedules by Ir192 HDR remote after-loading system. Using the formula Vpred=4965(TRAK/dref)3/2+170(TRAK/dref)-1.5 the TRAK based isodose surface volumes (Vpred) were derived. Reference doses (dref) were calculated based on accumulated EBRT and brachytherapy doses. The two sets of volume were compared with respect to applicator type, standard, and optimised plan. Surrogate point A dose was also correlated. VTPS - Vpred were 5.24 ± 2.7%, all volumes being predicted within 10%. Correlation of TRAK vs VTPS60/ VTPS75/ VTPS85 showed R2 of 0.994, 0.987 and 0.971 respectively. There was no significant difference in predicted volumes with respect to applicator type. The surrogate point A showed mean volume and standard deviation of 7.44 ± 13.4%, 17.63 ± 16.38 and 3.5 ± 0.95 for Manchester optimised, Fletcher optimised and standard plans respectively. TRAK with point A (R2=0.5632), bladder (R2=0.2015) and rectal doses (R2=0.121) yielded no correlation. Volumes calculated by TRAK correlate with TPS obtained volumes significantly and the formula predicting isodose surface volumes within 10% accuracy for ICBT applications and not for pure interstitial implants. However, TRAK fails to correlate with surrogate point A, bladder and rectal doses hence has questionable utility as a marker for biological response & treatment intensity.

Doses of fluoride toothpaste for children up to 24 months

AimThe aim of this study was to test the dose of fluoride toothpaste by parents for their children aged up to 24 months.MethodsParents who use fluoride toothpastes for their children were asked to dose two commercially available toothpastes (A and B) with 1000 ppm fluoride each for their children as they would normally do at home. The toothpaste amounts were weighed, and as reference, the weight of an ‘optimal’ grain of rice-size amount of each toothpaste was used.Results61 parents dosed a mean of 0.263 ± 0.172 g toothpaste A and 0.281 ± 0.145 g toothpaste B. The parents’ mean doses were 5.9 times higher for toothpaste A and 7.2 times higher for toothpaste B than an ‘optimal’ grain of rice-size amount (the reference dose as recommended). The difference between parent’s and reference dose was statistically significant (p < 0.001). Moreover, 39.3% of parents were not aware about conditions of use and warnings that have to be printed on the package of fluoride toothpastes.ConclusionIn this study, parents significantly overdosed the toothpaste for their children. To avoid fluoride intake from toothpaste, parents can choose fluoride-free alternatives for the oral care of their infants and toddlers.