Construction and Preclinical Evaluation of 124I/125I-Labeled Antibody Targeting T Cell Immunoglobulin and Mucin Domain-3.

T cell immunoglobulin and mucin domain-3 (TIM3; HAVCR2) is a transmembrane protein that exerts negative regulatory control over T cell responses. Studies have demonstrated an upregulation of TIM3 expression in tumor-infiltrating lymphocytes (TILs) in cancer patients. In this investigation, a series of monoclonal antibodies targeting TIM3 were produced by hybridoma technology. Among them, C23 exhibited favorable biological properties. To enable specific binding, we developed a 124I/125I-C23 radio-tracer via N-bromosuccinimide (NBS)-mediated labeling of the monoclonal antibody C23. Binding affinity and specificity were assessed using the 293T-TIM3 cell line, which overexpresses TIM3, and the parent 293T cells. Furthermore, biodistribution and in vivo imaging of 124I/125I-C23 were examined in HEK293TIM3 xenograft models and allograft models of 4T1 (mouse breast cancer cells) and CT26 (mouse colon cancer cells). Micro-PET/CT imaging was conducted at intervals of 4, 24, 48, 72, and/or 96 h post intravenous administration of 3.7-7.4 MBq 124I-C23 in the respective model mice. Additionally, immunohistochemistry (IHC) staining of TIM3 expression in dissected tumor organs was performed, along with an assessment of the corresponding expression of Programmed Death 1 (PD1), CD3, and CD8 in the tumors. The C23 monoclonal antibody (mAb) specifically binds to TIM3 protein with a dissociation constant of 23.28 nM. The 124I-C23 and 125I-C23 radio-tracer were successfully prepared with a labeling yield of 83.59 ± 0.35% and 92.35 ± 0.20%, respectively, and over 95.00% radiochemical purity. Stability results indicated that the radiochemical purity of 124I/125I-C23 in phosphate-buffered saline (PBS) and 5% human serum albumin (HSA) was still >80% after 96 h. 125I-C23 uptake in 293T-TIM3 cells was 2.80 ± 0.12%, which was significantly higher than that in 293T cells (1.08 ± 0.08%), and 125I-C23 uptake by 293T-TIM3 cells was significantly blocked at 60 and 120 min in the blocking groups. Pharmacokinetics analysis in vivo revealed an elimination time of 14.62 h and a distribution time of 0.4672 h for 125I-C23. Micro-PET/CT imaging showed that the 124I-C23 probe uptake in the 293T-TIM3 model significantly differed from that of the negative control group and blocking group. In the humanized mouse model, the 124I-C23 probe had obvious specific uptake in the 4T1 and CT26 models and maximum uptake at 24 h in tumor tissues (SUVmax (the maximum standardized uptake value) in 4T1 and CT26 humanized TIM3 murine tumor models: 0.59 ± 0.01 and 0.76 ± 0.02, respectively). Immunohistochemistry of tumor tissues from these mouse models showed comparable TIM3 expression. CD3 and CD8 cells and PD-1 expression were also observed in TIM3-expressing tumor tissues. The TIM3-targeting antibody C23 showed good affinity and specificity. The 124I/125I-C23 probe has obvious targeting specificity for TIM3 in vitro and in vivo. Our results suggest that 124I/125I-C23 is a promising tracer for TIM3 imaging and may have great potential in monitoring immune checkpoint drug efficacy.

Sorption of arsenic on manganese dioxide synthesized by solid state reaction.

Arsenic in groundwater is a major concern in many parts of the world and suitable sorbents are required for removal of arsenic from ground water. Removal of arsenic from groundwater has been studied using manganese dioxide, synthesized by solid state reaction of manganese acetate with potassium permanganate. Manganese dioxide was characterized by X-ray diffraction (XRD), zeta potential, surface area, particle size measurements and thermal analysis. XRD measurement showed that the manganese dioxide had α-MnO2 structure. Sorption of As(III) and As(V) on manganese dioxide was studied by radiotracer technique using (76)As radio isotope. Arsenic removal efficiency for both As(III) and As(V) at concentration of 2 mg L(-1) was ∼99% in the pH range of 3-9. The sorption capacities for As(III) and As(V) were ∼60 mg g(-1). Kinetic studies showed that the equilibrium was reached within 30 s. Arsenic sorbed on manganese dioxide was present as As(V) irrespective of initial oxidation state. The presence of Ca(2+), Mg(2+), Cl(-) and SO4(2-) up to a concentration of 1000 mg L(-1) had no significant effect on arsenic sorption. The sorption of arsenic decreased significantly in the presence of phosphate and bicarbonate anions above 10 mg L(-1). Arsenic sorbed on manganese dioxide was desorbed by 0.1M NaOH. Arsenic was effectively removed by manganese dioxide from groundwater samples collected from arsenic contaminated areas of West Bengal, India.

Interferon gamma immunoPET imaging to evaluate response to immune checkpoint inhibitors.

Introduction: We previously developed a 89Zr-labeled antibody-based immuno-positron emission tomography (immunoPET) tracer targeting interferon gamma (IFNγ), a cytokine produced predominantly by activated T and natural killer (NK) cells during pathogen clearance, anti-tumor immunity, and various inflammatory and autoimmune conditions. The current study investigated [89Zr]Zr-DFO-anti-IFNγ PET as a method to monitor response to immune checkpoint inhibitors (ICIs). Methods: BALB/c mice bearing CT26 colorectal tumors were treated with combined ICI (anti-cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and anti-programmed death 1 (PD-1)). The [89Zr]Zr-DFO-anti-IFNγ PET tracer, generated with antibody clone AN18, was administered on the day of the second ICI treatment, with PET imaging 72 hours later. Tumor mRNA was analyzed by quantitative reverse-transcribed PCR (qRT-PCR). Results: We detected significantly higher intratumoral localization of [89Zr]Zr-DFO-anti-IFNγ in ICI-treated mice compared to untreated controls, while uptake of an isotype control tracer remained similar between treated and untreated mice. Interestingly, [89Zr]Zr-DFO-anti-IFNγ uptake was also elevated relative to the isotype control in untreated mice, suggesting that the IFNγ-specific tracer might be able to detect underlying immune activity in situ in this immunogenic model. In an efficacy experiment, a significant inverse correlation between tracer uptake and tumor burden was also observed. Because antibodies to cytokines often exhibit neutralizing effects which might alter cellular communication within the tumor microenvironment, we also evaluated the impact of AN18 on downstream IFNγ signaling and ICI outcomes. Tumor transcript analysis using interferon regulatory factor 1 (IRF1) expression as a readout of IFNγ signaling suggested there may be a marginal disruption of this pathway. However, compared to a 250 µg dose known to neutralize IFNγ, which diminished ICI efficacy, a tracer-equivalent 50 µg dose did not reduce ICI response rates. Discussion: These results support the use of IFNγ PET as a method to monitor immune activity in situ after ICI, which may also extend to additional T cell-activating immunotherapies.

Evaluation of an ImmunoPET Tracer for IL-12 in a Preclinical Model of Inflammatory Immune Responses.

The immune cytokine interleukin-12 (IL-12) is involved in cancer initiation and progression, autoimmunity, as well as graft versus host disease. The ability to monitor IL-12 via imaging may provide insight into various immune processes, including levels of antitumor immunity, inflammation, and infection due to its functions in immune signaling. Here, we report the development and preclinical evaluation of an antibody-based IL-12-specific positron emission tomography (PET) tracer. To mimic localized infection and stimulate IL-12 production, BALB/c mice were administered lipopolysaccharide (LPS) intramuscularly. [89Zr]Zr-DFO-αIL12 tracer was given one hour post LPS administration and PET images were taken after 5, 24, 48, and 72 hours. We observed significantly higher uptake in LPS-treated mice as compared to controls. Biodistribution of the tracer was evaluated in a separate cohort of mice, where tracer uptake was elevated in muscle, spleen, lymph nodes, and intestines after LPS administration. To evaluate the utility of [89Zr]Zr-DFO-αIL12 as an indicator of antigen presenting cell activation after cancer immunotherapy, we compared PET imaging with and without intratumoral delivery of oncolytic adenovirus expressing granulocyte-macrophage colony-stimulating factor (Adv/GM-CSF), which we have shown promotes anti-tumor immunity. BALB/c mice were inoculated orthotopically with the mouse mammary carcinoma line TUBO. Once TUBO tumors reached a volume of ~50 mm3, mice were treated with either three intratumoral injections of 108 PFU Adv/GM-CSF or vehicle control, given every other day. Upon the last dose, [89Zr]Zr-DFO-αIL12 was injected intravenously and 72 hours later all mice were imaged via PET. Tumor-specific uptake of [89Zr]Zr-DFO-αIL12 was higher in Adv/GM-CSF treated mice versus controls. Tissues were harvested after imaging, and elevated levels of macrophages and CD8+ Tc cells were detected in Adv/GM-CSF treated tumors by immunohistochemistry. We validated that IL-12 expression was induced after Adv/GM-CSF by qRT-PCR. Importantly, expression of genes activated by IL-12 (IFNγ, TNFα, and IL-18) were unaffected after IL-12 imaging relative to mice receiving an IgG control tracer, suggesting the tracer antibody does not significantly disrupt signaling. Our results indicate that targeting soluble cytokines such as IL-12 by PET imaging with antibody tracers may serve as a noninvasive method to evaluate the function of the immune milieu in situ.

The efficacy of 99mTc-rituximab as a tracer for sentinel lymph node biopsy in cutaneous melanoma patients.

Background: The sentinel lymph node (SLN) status is a vital prognostic factor for malignant melanoma (MM) patients. There is increasing evidence that a radioactive agent, rather than its combination with blue dye, is sufficient for a SLN biopsy (SLNB). Thus, we discussed the efficacy of 99mTc-rituximab as a tracer in MM patients. Methods: A total of 502 consecutive patients with MM who underwent SLNB were enrolled in this study. All participants were peritumorally injected with 99mTc-rituximab before imaging, and scanned with single-photon emission computed tomography-computed tomography (SPECT-CT) to detect the number and location of the SLN. A gamma detection probe was employed to detect radioactive SLNs in operation. Follow up was conducted to observe whether nodal or distant recurrence occurred. Results: The SLNs were successfully imaged via SPECT-CT and harvested from all 502 participants. No drainage tube was indwelled and 32 (6.3%) participants experienced the following complications: seroma (n=26, 5.2%), wound infections or lymphangitis (n=6, 1.2%), sensory nerve injuries (n=4, 0.8%). There were 380 patients who were diagnosed as SLN-negative and 122 (24.2%) were SLN-positive. A total of 85 SLN-positive patients received complete lymph node dissection, and 28 (32.9%) had additional positive lymph nodes. During a median follow-up of 24 months, 28 participants were found to have a false negative (FN) SLN. The FN rate was 18.7%. A higher T stage was a predictive factor for FN [odds ratio (OR) 1.77; P<0.05]. There was no significant difference in the positive or FN rate between the acral and cutaneous groups. Conclusions: The radiopharmaceutical 99mTc-rituximab could be employed as a simple and safe tracer in acral and cutaneous melanoma SLN biopsies.

Tilmanocept as a novel tracer for lymphatic mapping and sentinel lymph node biopsy in melanoma and oral cancer.

BACKGROUND: Sentinel lymph node biopsy (SLNB) has been pivotal for pathological assessment of nodal status in cutaneous melanoma (CM) and oral cavity squamous cell carcinoma (OCSCC) thus crucial for staging. An ideal agent for lymphatic mapping should have a standardized preparation, appropriate accumulation in first-echelon nodes and no side effects. Tilmanocept, a CD206-receptor targeted novel radiotracer fulfils these properties. This study investigated Tilmanocept for lymphoscintigraphy and intraoperative identification of sentinel lymph nodes (SLN) in CM and OCSCC. METHODS: This prospective cross sectional study examined patients who presented to Crown Princess Mary Cancer Centre, Westmead Hospital, Sydney. Patients had biopsy proven tumours with clinically and radiologically negative regional lymph nodes. Tilmanocept guided lymphoscintigraphy was followed by intraoperative SLNs identification via handheld gamma probe. Primary endpoints were detection and retrieval rate of SLNs while secondary endpoints included pathological status of SLNs. RESULTS: Thirty-five patients were included (26 with CM and 9 with OCSCC) with the most common primary tumour site for CM on the extremities (33.3%). Lymphoscintigraphy with Tilmanocept identified at least 1 SLN (sensitivity 100%) in all patients. SLNs were retrieved in all of patients intraoperatively (100% retrieval rate) with positive nodes found in 20% of patients. Tilmanocept also demonstrated 100% tissue specificity, with lymph nodal tissue confirmed histologically, with no false positives. CONCLUSION: Tilmanocept is a reliable radiotracer for assessing the nodal status in patients with CM and OCSCC. Our group is the first to evaluate the use of Tilmanocept in the Australian setting, adding to the limited studies worldwide.

Tracers in Gastric Cancer Surgery.

The treatment of gastric cancer mainly depends on radical gastrectomy. Determination of appropriate surgical margins and adequate lymph node (LN) resection are two major surgical steps that directly correlate with prognosis in gastric cancer. Due to the expanding use of minimally invasive procedures, it is no longer possible to locate tumors and LNs through touch. As an alternative, tracers have begun to enter the field due to their capacities for intraoperative visualization. Herein, we summarize the application of contemporary tracers in gastric cancer surgery, including isosulfan blue, methylene blue, patent blue, indocyanine green, carbon particles, and radioactive tracers. Their mechanisms, administration methods, detection efficiency, and challenges, as well as perspectives on them, are also outlined.

Measurement of flux through sulfate assimilation using [35S]sulfate.

Sulfur metabolism provides a number of compounds that are essential for plant survival and fitness and that affect the yield and quality of crops. Sulfur metabolism is a dynamic process, responding to a number of external cues. Because of this dynamics and rapid turnover, steady-state levels of sulfur-containing compounds do not always fully reflect plant responses to such cues. Therefore, measurements of the flux through sulfate assimilation may give a more precise estimate of the effects of environmental stimuli or metabolic disturbances on sulfur metabolism. The flux can be determined after feeding plants with sulfate labelled with an isotopic tracer. Here we describe a protocol for using [35S]sulfate to measure flux through sulfate assimilation in Arabidopsis. The protocol can be adapted for any plant species and growth conditions, and does not require any special equipment beyond a standard high performance liquid chromatograph. We hope that the protocol will support our colleagues in a more frequent use of flux measurements to answer new biological questions in plant sulfur metabolism.

Translocator Protein (18 kDa) Polymorphism (rs6971) in the Korean Population.

Background and Purpose: The expression of the 18-kDA mitochondrial translocator protein (TSPO) in the brain is an attractive target to study neuroinflammation. However, the binding properties of TSPO ligands are reportedly dependent on genetic polymorphism of the TSPO gene (rs6971). The objective of this study is to investigate the rs6971 gene polymorphism in the Korean population. Methods: We performed genetic testing on 109 subjects including patients with mild cognitive impairment, Alzheimer's disease (AD) dementia, non-AD dementia, and cognitively unimpaired participants. Magnetic resonance imaging scans and detailed neuropsychological tests were also performed, and 29 participants underwent 18F-DPA714 PET scans. Exon 4 of the TSPO gene containing the polymorphism rs6971 (Ala or Thr at position 147) was polymerase chain reaction amplified and sequenced using the Sanger method. The identified rs6971 genotype codes (C/C, C/T, or T/T) of the TSPO protein generated high-, mixed-, or low-affinity binding phenotypes (HABs, MABs, and LABs), respectively. Results: We found that 96.3% of the study subjects were HAB (105 out of 109 subjects), and 3.7% of the subjects were MAB (4 out of 109 subjects). 18F-DPA-714 PET scans showed nonspecific binding to the thalamus and brainstem, and increased tracer uptake throughout the cortex in cognitively impaired patients. The participant with the MAB polymorphism had a higher DPA714 signal throughout the cortex. Conclusions: The majority of Koreans are HAB (aprox. 96%). Therefore, the polymorphism of the rs6971 gene would have a smaller impact on the availability of second-generation TSPO PET tracers.

"Live-Autoradiography" Technique Reveals Genetic Variation in the Rate of Fe Uptake by Barley Cultivars.

Iron (Fe) is an essential trace element in plants; however, the available Fe in soil solution does not always satisfy the demand of plants. Genetic diversity in the rate of Fe uptake by plants has not been broadly surveyed among plant species or genotypes, although plants have developed various Fe acquisition mechanisms. The "live-autoradiography" technique with radioactive 59Fe was adopted to directly evaluate the uptake rate of Fe by barley cultivars from a nutrient solution containing a very low concentration of Fe. The uptake rate of Fe measured by live autoradiography was consistent with the accumulation of Fe-containing proteins on the thylakoid membrane. The results revealed that the ability to acquire Fe from the low-Fe solution was not always the sole determinant of tolerance to Fe deficiency among barley genotypes. The live-autoradiography system visualizes the distribution of ß-ray-emitting nuclides and has flexibility in the shape of the field of view. This technique will strongly support phenotyping with regard to the long-distance transport of nutrient elements in the plant body.

EAU-EANM Consensus Statements on the Role of Prostate-specific Membrane Antigen Positron Emission Tomography/Computed Tomography in Patients with Prostate Cancer and with Respect to [177Lu]Lu-PSMA Radioligand Therapy.

BACKGROUND: Prostate-specific membrane antigen (PSMA) positron emission tomography (PET)/computed tomography (CT) is useful for selected clinical indications in patients with prostate cancer (PCa) but it may have broader clinical utility owing to the emergence of lutetium-177-PSMA-617 ([177Lu]Lu-PSMA) therapy. However, robust data regarding the impact of PSMA PET/CT on patient management and treatment are lacking, and in many areas, the role of next-generation imaging has not been defined. OBJECTIVE: To assess expert opinion on the use of PSMA-based imaging and therapy to develop interim guidance. DESIGN, SETTING, AND PARTICIPANTS: A panel of 21 PCa experts from various disciplines received thematic topics and relevant literature. A questionnaire to assess proposed guidance statements regarding PSMA PET/CT and [177Lu]Lu-PSMA therapy was developed for completion remotely in a first e-Delphi round. A subsequent panel discussion was conducted during a 1-d meeting, which included a second Delphi round. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Panellists voted anonymously on statements using a nine-point Likert scale from 1 = strongly disagree to 9 = strongly agree. Median scores were calculated and consensus was assessed using methods proposed by the Research and Development (RAND) corporation. RESULTS AND LIMITATIONS: Statements were developed to cover the following topics: PSMA PET/CT utility, clinical use, and choice of tracer; patient selection; and management of patients receiving [177Lu]Lu-PSMA for metastatic PCa. Consensus was reached for 33/36 statements. In-group bias is a potential limitation, as some statements were rephrased during discussions at the 1-d meeting. CONCLUSIONS: Adoption of PSMA PET/CT as an imaging tool to guide [177Lu]Lu-PSMA therapy should be supported by indications for appropriate use. PATIENT SUMMARY: A panel of experts in prostate cancer reached a consensus for the majority of statements proposed regarding the role of prostate-specific membrane antigen (PSMA)-based imaging and therapy, particularly the use of PSMA-based imaging in patients suitable for [177Lu]Lu-PSMA therapy and the need to perform PSMA-based imaging before considering patients as candidates for this therapy.

[18F]Fluorothymidine Uptake in the Porcine Pancreatic Elastase-Induced Model of Abdominal Aortic Aneurysm.

The porcine pancreatic elastase (PPE) model is a common preclinical model of abdominal aortic aneurysms (AAA). Some notable characteristics of this model include the low aortic rupture rate, non-progressive disease course, and infra-renal AAA formation. Enhanced [18F]fluorothymidine ([18F]FLT) uptake on positron emission tomography/computed tomography (PET/CT) has previously been reported in the angiotensin II-induced murine model of AAA. Here, we report our preliminary findings of investigating [18F]FLT uptake in the PPE murine model of AAA. [18F]FLT uptake was found to be substantially increased in the abdominal areas recovering from the surgery, whilst it was not found to be significantly increased within the PPE-induced AAA, as confirmed using in vivo PET/CT and ex vivo whole-organ gamma counting (PPE, n = 7; controls, n = 3). This finding suggests that the [18F]FLT may not be an appropriate radiotracer for this specific AAA model, and further studies with larger sample sizes are warranted to elucidate the pathobiology contributing to the reduced uptake of [18F]FLT in this model.

Use of a radiopharmaceutical multidose dispenser for positron emission tomography: Risk assessment and mitigation measures for infection prevention.

Positron emission tomography (PET) imaging necessitates the use of multidose vials for radiopharmaceutical delivery to patients. Conventional practices involve manual extraction of radiopharmaceuticals from a multidose vial prior to each PET procedure, which exposes the technologist to increasing levels of radiation and poses a potential infection risk to patients with frequent handling and access of the vial. New technologies for automated dosing and infusion delivery are available, however these incorporate both a multidose vial and a multi-patient infusion set. There is an absence of guidance for infection prevention (IP) units regarding the safety and acceptability of these devices. This paper describes the process of risk assessment and the mitigation measures for training, workflows, and documentation which led to the safe introduction of an automated PET infusion device in a large tertiary public healthcare facility.

Fluorine-18-Labeled PET Radiotracers for Imaging Tryptophan Uptake and Metabolism: a Systematic Review.

Due to its metabolism via the serotonin and kynurenine pathways, tryptophan plays a key role in multiple disease processes including cancer. Imaging tryptophan uptake and metabolism in vivo can be achieved with tryptophan derivative positron emission tomography (PET) radiotracers. While human studies with such tracers have been confined to C-11-labeled compounds, preclinical development of F-18-labeled tryptophan-based radiotracers has surged in recent years. We performed a systematic review of studies reporting on such F-18-labeled tryptophan tracers to summarize and compare their biological characteristics and their potential for tumor imaging, with a particular focus on key enzymes of the kynurenine pathway (indoleamine 2,3-dioxygenase [IDO] and tryptophan 2,3-dioxygenase [TDO]), which play an important role in tumoral immune resistance. From a PubMed search, English language articles including data on the preparation and radiochemical and/or biological characteristics of F-18-labeled tryptophan derivative radiotracers were reviewed. A total of 19 original papers included data on 15 unique radiotracers, the majority of which were synthesized with an adequate radiochemical yield. Automated synthesis was reported for 1-(2-[18F]fluoroethyl)-L-tryptophan, the most extensively evaluated tracer thus far. Biodistribution studies showed high uptake in the pancreas, while the L-type amino acid transporter was the dominant transport mechanism for most of the reviewed tracers. Tracers tested for tumor uptake showed accumulation in tumor cell lines in vitro and in xenografts in vivo, often with favorable tumor-to-background uptake ratios in comparison with clinically used F-18-labeled radiotracers. Five tracers showed promise for imaging IDO activity, including 1-(2-[18F]fluoroethyl)-L-tryptophan and a F-18-labeled analog of alpha-[11C]methyl-L-tryptophan tested clinically in previous studies. Two radiotracers were metabolized by TDO but showed defluorination in vivo. In summary, most F-18-labeled tryptophan derivative PET tracers share common transport mechanisms and biodistribution characteristics. Several reported tracers could be candidates for further testing and validation toward PET imaging applications in a variety of human diseases.

The bioaccumulation, elimination, and trophic transfer of BDE-47 in the aquatic food chain of Chlorella pyrenoidosa-Daphnia magna.

As a persistent organic pollutant, 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) has been widely detected in aquatic environments. However, studies on the fate and transfer of BDE-47 in the aquatic food chain remain scarce. In this study, we investigated the bioaccumulation and elimination of BDE-47 in Chlorella pyrenoidosa, as well as the trophic transfer and biomagnification of BDE-47 in the "C. pyrenoidosa-Daphnia magna" food chain, using C-14 radioactive tracer technology. After 96 h of BDE-47 exposure, the algae accumulated 88.98% ± 0.59% of the initial radioactivity from the medium, and 36.09% ± 9.22% of the accumulated residues in the algae occurred in the form of bound residues. During 96 h of elimination, only 13% ± 0.50% of accumulated radioactivity in the algae was released into the medium. After 24 h of exposure, D. magna accumulated 35.99% ± 2.55% of the initial radioactivity via water filtration from the medium, and 31.35% ± 1.92% of the accumulated radioactivity in D. magna occurred as bound residues. However, D. magna accumulated 66.89% ± 2.37% of the accumulated radioactivity in the algae via food uptake from the contaminated algae, with a high portion of radioactivity observed as bound residues (83.40% ± 0.97% of accumulated radioactivity in D. magna). This indicated a reduction in the environmental risk of BDE-47. There was obvious biomagnification in the food chain between C. pyrenoidosa and D. magna (biomagnification factors, BMFs>1), resulting in environmental hazard transfer in the aquatic food chain. However, no metabolite was found during the exposure experiment, and further studies should be carried out to investigate the intrinsic mechanisms of the trophic transfer of BDE-47, especially in multilevel food chains. Therefore, this study elucidated the effect of dietary uptake on the bioaccumulation of BDE-47 in D. magna and provided new insight for future analysis regarding the bioaccumulation and biomagnification of organic pollutants in the food chain.

The Established Nuclear Medicine Modalities for Imaging of Bone Metastases.

BACKGROUND: The skeleton is one of the frequent site of metastases in advanced cancer. Prostate, breast and renal cancers mostly metastasize to bone. DISCUSSION: Malignant tumors lead to significant morbidity and mortality. Identification of bone lesions is a crucial step in diagnosis of disease at early stage, monitoring of disease progression and evaluation of therapy. Diagnosis of cancer metastases is based on uptake of bone-targeted radioactive tracer at different bone remodeling sites. CONCLUSION: This manuscript summarizes already established and evolving nuclear medicine modalities (e.g. bone scan, SPECT, SPECT/CT, PET, PET/CT) for imaging of bone metastases.

Measuring Glycolytic and Mitochondrial Fluxes in Endothelial Cells Using Radioactive Tracers.

Endothelial cells (ECs) form the inner lining of the vascular network. Although they can remain quiescent for years, ECs exhibit high plasticity in both physiological and pathological conditions, when they need to rapidly form new blood vessels in a process called angiogenesis. EC metabolism recently emerged as an important driver of this angiogenic switch. The use of radioactive tracer substrates to assess metabolic flux rates in ECs has been essential for the discovery that fatty acid, glucose, and glutamine metabolism critically contribute to vessel sprouting. In the future, these assays will be useful as a tool for the characterization of pathological conditions in which deregulation of EC metabolism underlies and/or precedes the disease, but also for the identification of anti-angiogenic metabolic targets. This chapter describes in detail the radioactive tracer substrate assays that have been used for the determination of EC metabolic flux in vitro.

Cosmogenic beryllium-7 in soil, rainwater and selected plant species to evaluate the vegetal interception of atmospheric fine particulate matter.

Beryllium-7 is a radionuclide produced in the upper atmosphere by cosmic-ray spallation with ions of carbon, oxygen and nitrogen. It is one of radionuclides that can be used to trace the fine particulate matter of 2.5-µm diameter (PM2.5) and smaller. In this work, 7Be was determined in leaves of 10 plant species collected from streets, parks and open land and in 5 consecutive rains over Alexandria, Egypt. 7Be levels were also measured in soil covered by each type of plant as well as in the nearest uncovered soil to be reference values to determine its intercepted amount and consequently PM2.5. The lowest interception, 17.7 %, was by Ficus elastica L., while Ficus retusa L. intercepted about 45 %. Radiologically, the annual effective dose due to the usage of Thymelea hirsute plant leaves as a medicine and Nicotiana glauca Graham for smoking were 0.013 and 0.66 µSv, respectively. The observed levels in rainwater indicated that 7Be decreased consecutively from 3.1 Bq kg-1 in the first rain to 0.71 Bq kg-1 in the last one during the 2016/2017 rain season. The wet deposition of 7Be is less than 1 % of its total deposition on the ground.

Kinase Activity Determination of Specific AMPK Complexes/Heterotrimers in the Skeletal Muscle.

Measuring the kinase activity of the 5'-AMP-activated protein kinase (AMPK) is an essential part of understanding the regulation of this metabolic master switch. The AMPK heterotrimer can exist in 12 different constellations with potentially diverse activation patterns. It is therefore important to be able to measure heterotrimer-specific activity to discriminate between these patterns. In this chapter we describe how to measure the AMPK activity of specific heterotrimeric complexes by consecutive immunoprecipitations and how the assay can be performed in a medium throughput fashion using 96-well plates.

Assessment of Uptake and Biodistribution of Radiolabeled Cholesterol in Mice Using Gavaged Recombinant Triglyceride-rich Lipoprotein Particles (rTRL).

The here described method can be used to estimate the uptake of orally provided cholesterol in mice. Briefly, mice are gavaged with radiolabeled cholesterol and 4 h later, organ distribution of the radiolabel is determined by liquid scintillation counting. The method has been applied successfully to determine dietary cholesterol handling of mice housed at different ambient temperatures.