Browsing by Author "Chapman, J"
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- ItemAn analysis of molybdenum-99 expiry times in sodium pertechnetate derived from a dry-bed generator(Australian Nuclear Science and Technology Organisation, 2000-03) Barnes, RK; Anderson, PJ; Stimson, D; Chapman, J; Druce, MJFission-based 99 Mo/ 99m Tc generators have undergone evolutionary changes since they were first manufactured at the Lucas Heights Laboratories in the late 1960s for the Australian nuclear medicine community. This study is aimed at understanding the chemistries which influence the behaviour of the heterogeneous molybdenum-alumina system in a chromatographic generator. The quality of sodium pertechnetate derived from a dry-bed generator is enhanced when compared with the traditional wet-bed technologies. Data is presented which compare the extent of 99Mo desorption from both wet and dry-bed chromatographic generators. The expiration times for sodium pertechnetate based on 99Mo breakthrough are significantly greater for the recently developed dry-bed generators.
- ItemDetection of apoptotic cell death in the thymus of dexamethasone treated rats using [123I]Annexin V and in situ oligonucleotide ligation(Springer Nature, 2007-06-29) Zavitsanou, K; Nguyen, VH; Greguric, I; Chapman, J; Ballantyne, P; Katsifis, AIn the present study we aimed to establish an animal model of dexamethasone (DEX)-induced apoptosis in the thymus of rats. The degree of apoptosis was determined in the same animals at 6 and 11 h after a single administration of DEX (5 mg/kg, ip) by (a) in vivo biodistribution of the uptake of [123I]Annexin V, a biomarker of the early stages of apoptosis; (b) in vitro evaluation of the apoptotic index (percentage of number of apoptotic cells versus total number of cells) in the form of DNA fragmentation, on tissue sections using in situ oligo ligation (ISOL). ISOL demonstrated a 62- and 90-fold increase of apoptotic index at 6 and 11 h after DEX administration respectively, in the outer part of the thymic lobule (cortex) and a 25- and 54-fold increases in the inner part of the thymic lobule (medulla) in the corresponding treatment groups. In the biodistribution study, [123I]Annexin V uptake was significantly increased in the thymus of rats 11 h after DEX administration (by 1.3- to 1.4-fold) and significantly decreased at the 6-h time point. We conclude that the specificity of the apoptotic signal provided by isotopic methods in vivo would always require confirmation by complementary in vitro techniques that verify the assessment of ongoing apoptosis accurately. © 2007 Springer Science+Business Media B.V.
- ItemA DNA-based assay for toxic chemicals in wastewater(Wiley-Blackwell, 2011-08-01) Foreman, AL; Philips, L; Kanellis, VG; Hammoudeh, D; Naumann, C; Wong, HKY; Chisari, R; Hibbert, DB; Lee, GSH; Patra, R; Julli, M; Chapman, J; Cooke, AR; dos Remedios, CGChemical toxicants, particularly metal ions, are a major contaminant in global waterways. Live-organism bioassays used to monitor chemical toxicants commonly involve measurements of activity or survival of a freshwater cladoceran (Ceriodaphnia dubia) or light emitted by the marine bacterium Vibrio fischeri, used in the commercial Microtox (R) bioassay. Here we describe a novel molecule-based assay system employing DNA as the chemical biosensor. Metals bind to DNA, causing structural changes that expel a bound (intercalated) fluorescent reporter dye. Analyses of test data using 48 wastewater samples potentially contaminated by metal ions show that the DNA-dye assay results correlate with those from C. dubia and Microtox bioassays. All three assays exhibit additive, antagonistic, and synergistic responses that cannot be predicted by knowing individual metal concentrations. Analyses of metals in these samples imply the presence of chemical toxicants other than metal ions. The DNA-dye assay is robust, has a 12-month shelf life, and is only slightly affected by sample pH in the range 4 to 9. The assay is completed in a matter of minutes, and its portability makes it well suited as a screening assay for use in the field. We conclude that the DNA-dye test is a surrogate bioassay suitable for screening chemical toxicity. Environ. Toxicol. Chem. 2011;30:1810-1818. (C) 2011 SETAC
- ItemSynthesis and evaluation of novel radioiodinated benzamides for malignant melanoma(American Chemical Society, 2007-07-26) Pham, TQ; Greguric, I; Liu, X; Berghofer, PJ; Ballantyne, P; Chapman, J; Mattner, F; Dikic, B; Jackson, TW; Loc'h, C; Katsifis, AThe imaging potential of a series of [123I]benzamides was studied in mice bearing B16F0 melanoma tumors. Compound [123I]25 exhibited tumor uptake >8 %ID/g at 1 h, while that of [123I]14d and [123I]25 reached a maximum of 9−12 %ID/g at 6 h. Standardized uptake values of [123I]14d were higher than 100 between 24 and 72 h after injection. In haloperidol treated animals, the tumor uptake of [123I]14d was not significantly different to controls, while significant reduction of [123I]25 uptake was observed, supporting that [123I]14d uptake relates to melanin interaction, whereas part of the mechanism of [123I]25 uptake is related to its σ1-receptor affinity. Benzamides 14d and 25, which display rapid and high tumor uptake, appear to be promising imaging agents for melanoma detection, while 14d, which displays a long lasting and high melanoma/nontarget ratio, is more suitable for evaluation as a potential radiotherapeutic. © 2007, American Chemical Society.
- ItemSynthesis and evaluation of novel radioiodinated nicotinamides for malignant melanoma(Elsevier B.V., 2008-10-01) Liu, X; Pham, TQ; Berghofer, PJ; Chapman, J; Greguric, I; Mitchell, P; Mattner, F; Loc'h, C; Katsifis, AIntroduction A series of iodonicotinamides based on the melanin-binding iodobenzamide compound N-2-diethylaminoethyl-4-iodobenzamide was prepared and evaluated for the potential imaging and staging of disseminated metastatic melanoma. Methods [123I]Iodonicotinamides were prepared by iododestannylation reactions using no-carrier-added iodine-123 and evaluated in vivo by biodistribution and competition studies and by single photon emission computed tomography (SPECT) imaging in black and albino nude mice bearing B16F0 murine melanotic and A375 human amelanotic melanoma tumours, respectively. Results The iodonicotinamides displayed low-affinity binding for σ1–σ2 receptors (Ki>300 nM). In biodistribution studies in mice, N-(2-(diethylamino)ethyl)-5-[123I]iodonicotinamide ([123I]1) exhibited the fastest and highest uptake of the nicotinamide series in the B16F0 tumour at 1 h (∼8% ID/g), decreasing slowly over time. No uptake was observed in the A375 tumour. Clearance from the animals by urinary excretion was more rapid for N-alkyl-nicotinamides than for piperazinyl derivatives. At 1 h postinjection, the urinary excretion was 66% ID for [123I]1, while the gastrointestinal tract amounted to 17% ID. Haloperidol was unable to reduce the uptake of [123I]1 in pigmented mice, indicating that this uptake was likely due to an interaction with melanin. SPECT imaging of [123I]1 in black mice bearing the B16F0 melanoma indicated that the radioactivity was predominately located in the tumour and eyes. No specific localisation was observed in nude mice bearing A375 amelanotic tumours. Conclusion These findings suggest that [123I]1, which displays high tumour uptake with rapid clearance from the body, could be a promising imaging agent for the detection of melanotic tumours. © 2008 Elsevier Inc.
- ItemTowards sustainable environmental quality: priority research questions for the Australasian region of Oceania(John Wiley & Sons, Inc, 2019-07-05) Gaw, S; Harford, A; Pettigrove, VJ; Sevicke-Jones, G; Manning, T; Ataria, J; Cresswell, T; Dafforn, KA; Leusch, FDL; Moggridge, B; Cameron, M; Chapman, J; Coates, G; Colville, A; Death, C; Hageman, K; Hassell, KL; Hoak, M; Gadd, JB; Jolley, DF; Karami, A; Kotzakoulakis, K; Lim, R; McRae, N; Metzeling, L; Mooney, T; Myers, J; Pearson, A; Saaristo, M; Sharley, D; Stuthe, J; Sutherland, O; Thomas, O; Tremblay, L; Wood, W; Boxall, ABA; Rudd, MA; Brooks, BWEnvironmental challenges persist across the world, including the Australasian region of Oceania, where biodiversity hotspots and unique ecosystems such as the Great Barrier Reef are common. These systems are routinely affected by multiple stressors from anthropogenic activities, and increasingly influenced by global megatrends (e.g., the food–energy–water nexus, demographic transitions to cities) and climate change. Here we report priority research questions from the Global Horizon Scanning Project, which aimed to identify, prioritize, and advance environmental quality research needs from an Australasian perspective, within a global context. We employed a transparent and inclusive process of soliciting key questions from Australasian members of the Society of Environmental Toxicology and Chemistry. Following submission of 78 questions, 20 priority research questions were identified during an expert workshop in Nelson, New Zealand. These research questions covered a range of issues of global relevance, including research needed to more closely integrate ecotoxicology and ecology for the protection of ecosystems, increase flexibility for prioritizing chemical substances currently in commerce, understand the impacts of complex mixtures and multiple stressors, and define environmental quality and ecosystem integrity of temporary waters. Some questions have specific relevance to Australasia, particularly the uncertainties associated with using toxicity data from exotic species to protect unique indigenous species. Several related priority questions deal with the theme of how widely international ecotoxicological data and databases can be applied to regional ecosystems. Other timely questions, which focus on improving predictive chemistry and toxicology tools and techniques, will be important to answer several of the priority questions identified here. Another important question raised was how to protect local cultural and social values and maintain indigenous engagement during problem formulation and identification of ecosystem protection goals. Addressing these questions will be challenging, but doing so promises to advance environmental sustainability in Oceania and globally. © 2019 The Authors