The usefulness of mesocosms for ecotoxicity testing with lacertid lizards

Mesocosms (i.e., outdoor, man-made representations of natural ecosystems) have seldom been used to study the impact of contaminants on terrestrial ecosystems. However, mesocosms can be a useful tool to provide a link between field and laboratory studies. We exposed juvenile lacertid lizards for a period of over one year to pesticides (herbicides and insecticides) in mesocosm enclosures with the intention of validating field observations obtained in a previous study that examined the effects of corn pesticides in Podarcis bocagei. Our treatments replicated field conditions and consisted of a control, an herbicides only treatment (alachlor, terbuthylazine, mesotrione and glyphosate) and an herbicides and insecticide treatment (including chlorpyrifos). We used a multi-biomarker approach that examined parameters at an individual and sub-individual level, including growth, locomotor performance, standard metabolic rate, biomarkers of oxidative stress, esterases and liver histopathologies. Although mortality over the course of the exposures was high (over 60%), surviving individuals prospered relatively well in the mesocosms and displayed a broad range of natural behaviours. The low numbers of replicate animals compromised many of the statistical comparisons, but in general, surviving lizards exposed to pesticides in mesocosm enclosures for over one year, thrived, and displayed few effects of pesticide exposure. Despite the difficulties, this work acts as an important stepping-stone for future ecotoxicology studies using lizards.publishe

Novel Preparation Methods of ⁵²Mn for ImmunoPET Imaging

52Mn (t1/2 =5.59 d, ß+ = 29.6%, Eßave = 0.24 MeV) shows promise in positron emission tomography (PET) and in dual-modality manganese-enhanced magnetic resonance imaging (MEMRI) applications including neural tractography, stem cell tracking, and biological toxicity studies. The extension to bioconjugate application requires high specific activity 52Mn in a state suitable for macromolecule labeling. To that end a 52Mn production, purification, and labeling system is presented, and its applicability in preclinical, macromolecule PET is shown using the conjugate 52Mn-DOTA-TRC105. 52Mn is produced by 60 µA, 16 MeV proton irradiation of natural chromium metal pressed into a silver disc support. Radiochemical separation proceeds by strong anion exchange chromatography of the dissolved Cr target, employing a semi-organic mobile phase, 97:3 (v:v) ethanol: HCl (11M, aqueous). The method is 62 ± 14% efficient (n=7) in 52Mn recovery, leading to a separation factor from Cr of (1.6 ± 1.0) x106 (n = 4), and an average effective specific activity of 0.8 GBq/µmol (n = 4) in titration against DOTA. 52Mn-DOTA-TRC105 conjugation and labeling demonstrate the potential for chelation applications. In vivo images acquired using PET/CT in mice bearing 4T1 xenograft tumors are presented. Peak tumor uptake is 18.7 ± 2.7 %ID/g at 24 hours post injection and ex vivo 52Mn biodistribution validates the in vivo PET data. Free 52Mn2+(as chloride or acetate) is used as a control in additional mice to evaluate the non-targeted biodistribution in the tumor model

Integrating sequence and array data to create an improved 1000 Genomes Project haplotype reference panel

A major use of the 1000 Genomes Project (1000GP) data is genotype imputation in genome-wide association studies (GWAS). Here we develop a method to estimate haplotypes from low-coverage sequencing data that can take advantage of single-nucleotide polymorphism (SNP) microarray genotypes on the same samples. First the SNP array data are phased to build a backbone (or 'scaffold') of haplotypes across each chromosome. We then phase the sequence data 'onto' this haplotype scaffold. This approach can take advantage of relatedness between sequenced and non-sequenced samples to improve accuracy. We use this method to create a new 1000GP haplotype reference set for use by the human genetic community. Using a set of validation genotypes at SNP and bi-allelic indels we show that these haplotypes have lower genotype discordance and improved imputation performance into downstream GWAS samples, especially at low-frequency variants. © 2014 Macmillan Publishers Limited. All rights reserved

Developments in Combining Targeted Radionuclide Therapies and Immunotherapies for Cancer Treatment

Targeted radionuclide therapy (TRT) and immunotherapy are rapidly growing classes of cancer treatments. Basic, translational, and clinical research are now investigating therapeutic combinations of these agents. In comparison to external beam radiation therapy (EBRT), TRT has the unique advantage of treating all disease sites following intravenous injection and selective tumor uptake and retention—a particularly beneficial property in metastatic disease settings. The therapeutic value of combining radiation therapy with immune checkpoint blockade to treat metastases has been demonstrated in preclinical studies, whereas results of clinical studies have been mixed. Several clinical trials combining TRT and immune checkpoint blockade have been initiated based on preclinical studies combining these with EBRT and/or TRT. Despite the interest in translation of TRT and immunotherapy combinations, many questions remain surrounding the mechanisms of interaction and the optimal approach to clinical implementation of these combinations. This review highlights the mechanisms of interaction between anti-tumor immunity and radiation therapy and the status of basic and translational research and clinical trials investigating combinations of TRT and immunotherapies

Detrimental Effects of Radiation on the Fluorescence of Fluorophores: Implications for Dual-Modality Imaging

Aim: Despite the large interest on nuclear/optical multimodality imaging, the effect of radiation on the fluorescence properties of fluorophores remains unknown. Herein we determined the radiosensitivity of the near infrared dye IRDye800CW, and devised a strategy to ameliorate its negative impact for multimodality imaging. Materials and Methods: Buffered aqueous solutions of IRDye800CW were incubated in the presence of increasing activities of 111In, 68Ga, or 213Bi (γ, β, and α emitter, respectively) and its normalized fluorescence (λex=740 nm and λem=796 nm) was determined at different radiation exposure times. The radioprotective effect of three hydroxyl radical scavengers (ethanol, gentisic acid, and ascorbic acid (AA)), was examined. The impact of other factors such as activity concentration, temperature, type of buffer, and pH on the fluorescence properties of IRDye800CW was also determined. Similar experiments were conducted on RDC018, a DOTA-conjugated IRDye800CW-derivative used as multimodality imaging probe in pretargeting. Results: A significant decrease of the fluorescence of IRDye800CW was observed upon incubation with escalating activities of 111In, 68Ga or 213Bi. The effect was dependent on the amount of activity as well as the type of radiation, which supported our hypothesis of a free radical-mediated mechanism. 68Ga showed the largest radiolytic effect – the fluorescence signal of the fluorophore was reduced to background levels within 30 min incubation with 20 MBq of 68Ga-, followed by 111In and 213Bi. IRDye800CW and RDC018 presented similar radiosensitivity except for 213Bi-labelled RDC018, which exhibited enhanced radiolysis, presumably due to direct radiation damage induced by α particles. The addition of scavengers provided a concentration dependent radioprotective effect. Among all scavengers, AA provided the most robust protection over a wide range of concentrations and preserved RDC018 fluorescence at much higher activity levels. Interestingly, AA afforded only partial radioprotection of 213Bi-RDC018, which further supported our hypothesis of α particle-fluorophore direct interaction. Conclusion: Herein we provide the first report on the radiosensitivity of fluorophores, and outline a set of conditions that minimize the deleterious effects of radiation damage on nuclear/optical multimodality imaging probes.JRC.E.5-Nuclear chemistr

The Importance of Animal Models in Tuberculosis Vaccine Development

Research, development, and production of vaccines are still highly dependent on the use of animal models in the various evaluation steps. Despite this fact, there are strong interests and ongoing efforts to reduce the use of animals in vaccine development. Tuberculosis vaccine development is one important example of the complexities involved in the use of animal models for the production of new vaccines. This review summarises some of the general aspects related with the use of animals in vaccine research and production, as well as achievements and challenges towards the rational use of animals, particularly in the case of tuberculosis vaccine development

Pretargeted radioimmunotherapy with Bi-213 in mice with CEA-expressing colon cancer xenografts

Pretargeted radioimmunotherapy (PRIT) with TF2, an anti-CEA x anti-HSG bispecific antibody, and 177Lu-labeled di-HSG-DOTA peptide IMP288, can delay tumor growth of CEA-expressing colon cancer xenografts. The therapeutic efficacy of PRIT may be improved by using alpha-emitting radionuclides. The aim of this study was to assess the potential of 213Bi for PRIT.JRC.E.5-Nuclear chemistr

Preventing Radiobleaching of Cyanine Fluorophores Enhances Stability of Nuclear/NIRF Multimodality Imaging Agents

Despite the large interest on nuclear/optical multimodality imaging, the effect of radiation on the fluorescence of fluorophores remains unexplored. Herein we determined the radiosensitivity of two near infrared fluorescent compounds, IRDye 800CW (800CW) and a dual modality imaging tetrapeptide containing DOTA as chelator and Dylight 800 as fluorophore, exposed to increasing activities of 111In, 68Ga, or 213Bi (γ, β, and α emitter, respectively). An activity and type of radiation-dependent radiation-induced loss of fluorescence, radiobleaching, of 800CW was observed upon incubation with escalating activities of 111In, 68Ga, or 213Bi. 68Ga showed the largest radiolytic effect, followed by 111In and 213Bi. The addition of oxygen radical scavengers including ethanol, gentisic acid, and ascorbic acid (AA), provided a concentration dependent radioprotective effect. These results supported the hypothesis of a free radical-mediated radiobleaching mechanism. AA provided the most robust radioprotection over a wide range of concentrations and preserved fluorescence at much higher radioactivity levels. Overall, both fluorescent compounds displayed similar sensitivity, except for 213Bi-irradiated solutions, where the dual modality construct exhibited enhanced radiolysis, presumably due to direct radiation damage from α particles. Concurrently, AA was not able to preserve fluorescence of the dual-modality molecule labeled with 213Bi. Herein we report on the radiobleaching of fluorophores, and describe conditions to provide robust radioprotection under practical (pre)clinical conditions. Our recommendations have strong repercussions for the preparation of dual-modality radiopharmaceuticals.JRC.G.I.5-Advanced Nuclear Knowledg