Approaches to risk-benefit assessment of seafood consumption: lessons learned from an evidence scan

Qualitative and quantitative risk-benefit assessments (RBA) can be used to support public health decisions in food safety. We conducted an evidence scan to understand the state of the science regarding RBA in seafood to help inform seafood dietary advice in the United States. We collected published RBA studies assessing seafood consumption, designed inclusion and exclusion criteria to screen these studies, and conducted systematic data extraction for the relevant studies published since 2019. Our findings indicate the selection of health risks and benefits does not generally follow a systematic approach. Uncertainty and variability in RBAs is often not addressed, and quantitative RBAs making use of a single health metric generally have not been leveraged to directly support published regulatory decisions or dietary guidance. To elevate the role of RBA in supporting regulatory decision-making, risk assessors and risk managers must work together to set expectations and goals. We identified the need for a prioritization phase (e.g., multicriteria decision analysis model) to determine the risks and benefits of greatest public health impact to inform the RBA design. This prioritization would consider not only the degree of public health impact of each risk and benefit, but also the potential for risks and benefits to converge on common health outcomes and their importance to subpopulations. Including a prioritization could improve the utility of the RBAs to better inform risk management decisions and advance public health. Our work serves to guide the United States Food and Drug Administration's approaches to RBA in foods.

Cadmium and lead bioavailability to poultry fed with contaminated soil-spiked feed

Geophagy is common for free-range chickens, however, the relative bioavailability (RBA) of heavy metals in contaminated soils consumed by chickens has not fully investigated. In this work, chickens were fed diets increasingly spiked with a contaminated soil (Cd = 105, Pb = 4840 mg kg^-1; 3, 5, 10, 20 and 30 % of overall feed by weight), or Cd/Pb reagent spikes (from CdCl₂ or Pb(Ac)₂), for 23 d. After the study period, chicken liver, kidney, femur and gizzard samples were analyzed for Cd and Pb concentrations, and organ/tissue metal concentrations were used to calculate Cd and Pb RBA. Linear dose response curves (DRCs) were established for both Cd/Pb reagents-spiked and soil-spiked treatments. Femur Cd concentrations of soil-spiked treatments were two times of Cd-spiked treatments with similar feed Cd levels, while feed spiked with Cd or Pb also resulted in elevated Pb or Cd concentrations in some organ/tissues. Metal RBA was calculated using three different methods. Most Cd and Pb RBA values were in the range 50-70 %, with the chicken gizzard as a potential endpoint for bioaccessible Cd and Pb. Cadmium and Pb bioavailability values can help with more precise estimation of Cd and Pb accumulation in chicken following heavy metal-contaminated soil ingestion, with overall results helping to protect human health.

Extrusion 3D printing of minicaplets for evaluating in vitro & in vivo praziquantel delivery capability

This study aimed to explore extrusion three dimensional (3D) printing technology to develop praziquantel (PZQ)-loaded minicaplets and evaluate their in vitro and in vivo delivery capabilities. PZQ-loaded minicaplets were 3D printed using a fused deposition modelling (FDM) principle-based extrusion 3D printer and were further characterized by different in vitro physicochemical and sophisticated analytical techniques. In addition, the % PZQ entrapment and in vitro PZQ release performance were evaluated using chromatographic techniques. It was in vitro observed that PZQ was fully released in the gastric pH medium within the period of gastric emptying, that is, 120 min, from the PZQ-loaded 3D printed minicaplets. Furthermore, in vivo pharmacokinetic (PK) profiles of PZQ-loaded 3D printed minicaplets were systematically evaluated using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The PK profile of the PZQ-loaded 3D printed minicaplets was established using different parameters such as C_max, T_max, AUC_0-t, AUC_0-∞, and oral relative bioavailability (RBA). The C_max value of pristine PZQ was found at 64.79 ± 13.99 ng/ml, while PZQ-loaded 3D printed minicaplets showed a C_max of 263.16 ± 47.85 ng/ml. Finally, the PZQ-loaded 3D printed minicaplets showed 9.0-fold improved oral RBA compared with that of pristine PZQ (1.0-fold). Together, these observations potentiate the desired in vitro and improved in vivo delivery capabilities of PZQ from the PZQ-loaded 3D printed minicaplets.

Plumbojarosite Remediation of Soil Affects Lead Speciation and Elemental Interactions in Soil and in Mice Tissues

Lead (Pb) contamination of soils is of global concern due to the devastating impacts of Pb exposure in children. Because early-life exposure to Pb has long-lasting health effects, reducing exposure in children is a critical public health goal that has intensified research on the conversion of soil Pb to low bioavailability phases. Recently, plumbojarosite (PLJ) conversion of highly available soil Pb was found to decrease Pb relative bioavailability (RBA <10%). However, there is sparse information concerning interactions between Pb and other elements when contaminated soil, pre- and post-remediation, is ingested and moves through the gastrointestinal tract (GIT). Addressing this may inform drivers of effective chemical remediation strategies. Here, we utilize bulk and micro-focused Pb X-ray absorption spectroscopy to probe elemental interactions and Pb speciation in mouse diet, cecum, and feces samples following ingestion of contaminated soils pre- and post-PLJ treatment. RBA of treated soils was less than 1% with PLJ phases transiting the GIT with little absorption. In contrast, Pb associated with organics was predominantly found in the cecum. These results are consistent with transit of insoluble PLJ to feces following ingestion. The expanded understanding of Pb interactions during GIT transit complements our knowledge of elemental interactions with Pb that occur at higher levels of biological organization.

Application of Six Detection Methods for Analysis of Paralytic Shellfish Toxins in Shellfish from Four Regions within Latin America

With the move away from use of mouse bioassay (MBA) to test bivalve mollusc shellfish for paralytic shellfish poisoning (PSP) toxins, countries around the world are having to adopt non-animal-based alternatives that fulfil ethical and legal requirements. Various assays have been developed which have been subjected to single-laboratory and multi-laboratory validation studies, gaining acceptance as official methods of analysis and approval for use in some countries as official control testing methods. The majority of validation studies conducted to date do not, however, incorporate shellfish species sourced from Latin America. Consequently, this study sought to investigate the performance of five alternative PSP testing methods together with the MBA, comparing the PSP toxin data generated both qualitatively and quantitatively. The methods included a receptor binding assay (RBA), two liquid chromatography with fluorescence detection (LC-FLD) methods including both pre-column and post-column oxidation, liquid chromatography with tandem mass spectrometry (LC-MS/MS) and a commercial lateral flow assay (LFA) from Scotia. A total of three hundred and forty-nine shellfish samples from Argentina, Mexico, Chile and Uruguay were assessed. For the majority of samples, qualitative results compared well between methods. Good statistical correlations were demonstrated between the majority of quantitative results, with a notably excellent correlation between the current EU reference method using pre-column oxidation LC-FLD and LC-MS/MS. The LFA showed great potential for qualitative determination of PSP toxins, although the findings of high numbers of false-positive results and two false negatives highlighted that some caution is still needed when interpreting results. This study demonstrated that effective replacement methods are available for countries that no longer wish to use the MBA, but highlighted the importance of comparing toxin data from the replacement method using local shellfish species of concern before implementing new methods in official control testing programs.

Overview of the detection methods for equilibrium dissociation constant KD of drug-receptor interaction

Drug-receptor interaction plays an important role in a series of biological effects, such as cell proliferation, immune response, tumor metastasis, and drug delivery. Therefore, the research on drug-receptor interaction is growing rapidly. The equilibrium dissociation constant (KD) is the basic parameter to evaluate the binding property of the drug-receptor. Thus, a variety of analytical methods have been established to determine the KD values, including radioligand binding assay, surface plasmon resonance method, fluorescence energy resonance transfer method, affinity chromatography, and isothermal titration calorimetry. With the invention and innovation of new technology and analysis method, there is a deep exploration and comprehension about drug-receptor interaction. This review discusses the different methods of determining the KD values, and analyzes the applicability and the characteristic of each analytical method. Conclusively, the aim is to provide the guidance for researchers to utilize the most appropriate analytical tool to determine the KD values.

Molecular Profiling and Malignant Behavior Define Two Rat Mammary Tumor Cell Lines as a Relevant Experimental Model

Cancer cell lines have become a reliable tool in genetic and biochemical studies of breast cancer. Here, we described the behavior and novel molecular characterization of two cell lines derived from DMBA-induced rat mammary tumor, LA7 and RBA. LA7 cells have been identified as myoepithelial cells with stem cell properties, whereas the RBA cell line are epithelial cells that present mutational activated H-Ras, but are much less known. We evaluated the proliferation rate and molecular markers, several signaling pathways status related to proliferation, survival, inflammation, and apoptosis, as well as migration capacity, global DNA methylation levels, and stem cells populations. In fact, we found the A/T transversion in the c-Ha-Ras codon 61 as the activator mutation origin described in RBA cells. LA7 and RBA cells showed a high proliferation rate associated with overexpression of Cyclin D1, and resistance to apoptotic signals due to lack of expression of Bad. Moreover, neither of these two cell lines expressed steroid receptors, but they showed high migration capacity, all in accordance with an aggressive phenotype. We found global DNA methylation levels in LA7 and RBA cells lower than reference tissues analyzed, in addition to the presence of different stem cells populations in RBA cell line that differed in the expression of CD44 and CD24. These results revealed a malignant behavior associated with cancer stem cell phenotype. Since this profile is similar to a human triple-negative basal-like tumor, their extensive characterization presented herein increases their value as a good in vitro model. J. Cell. Biochem. 117: 2825-2834, 2016. © 2016 Wiley Periodicals, Inc.

Identification of putative estrogen receptor-mediated endocrine disrupting chemicals using QSAR- and structure-based virtual screening approaches

Identification of endocrine disrupting chemicals is one of the important goals of environmental chemical hazard screening. We report on the development of validated in silico predictors of chemicals likely to cause estrogen receptor (ER)-mediated endocrine disruption to facilitate their prioritization for future screening. A database of relative binding affinity of a large number of ERα and/or ERβ ligands was assembled (546 for ERα and 137 for ERβ). Both single-task learning (STL) and multi-task learning (MTL) continuous quantitative structure-activity relationship (QSAR) models were developed for predicting ligand binding affinity to ERα or ERβ. High predictive accuracy was achieved for ERα binding affinity (MTL R(2)=0.71, STL R(2)=0.73). For ERβ binding affinity, MTL models were significantly more predictive (R(2)=0.53, p<0.05) than STL models. In addition, docking studies were performed on a set of ER agonists/antagonists (67 agonists and 39 antagonists for ERα, 48 agonists and 32 antagonists for ERβ, supplemented by putative decoys/non-binders) using the following ER structures (in complexes with respective ligands) retrieved from the Protein Data Bank: ERα agonist (PDB ID: 1L2I), ERα antagonist (PDB ID: 3DT3), ERβ agonist (PDB ID: 2NV7), and ERβ antagonist (PDB ID: 1L2J). We found that all four ER conformations discriminated their corresponding ligands from presumed non-binders. Finally, both QSAR models and ER structures were employed in parallel to virtually screen several large libraries of environmental chemicals to derive a ligand- and structure-based prioritized list of putative estrogenic compounds to be used for in vitro and in vivo experimental validation.

Steroid-linked nitrogen mustards as potential anticancer therapeutics: a review

Nitrogen mustards, an important class of drugs for cancer therapy, are known as DNA alkylating agents. The nitrogen mustards are highly reactive and, as a consequence, lack of selectivity and produce several adverse side effects. In order to minimize these undesirable effects, the attachment of nitrogen mustards to a steroidal hormone with affinity for its receptor can lead to highly selective and less toxic antineoplastic therapeutics. This review will focus on the design, synthesis and evaluation of such steroid-nitrogen mustard hybrids as antineoplastic agents. Among these compounds, modified steroids with aromatic nitrogen mustards linked by an ester function were found to have better DNA alkylating properties, improved selectivity as well as low toxicity. This article is part of a Special Issue entitled "Synthesis and biological testing of steroid derivatives as inhibitors".