Small zinc doped iron oxide tracers for magnetic particle imaging

Magnetic particle imaging (MPI) has garnered significant attention in biomedical imaging research due to its excellent signal intensity that is generated directly from superparamagnetic iron oxide nanoparticles (SPIONs). Small nanoparticle tracers with high saturation magnetisation are crucial for MPI as they can prolong circulation, crossing the blood brain barrier and enhance cellular uptake. In this work, we demonstrate small zinc doped iron oxide nanoparticles (Zn-IONPs) are excellent MPI tracers. Our Zn-IONPs exhibited up to 37 % and 64% enhancement in saturation magnetisation (Msat) value and MPI signal intensity respectively compared to Fe3O4 of the same size. As a result, the polymer encapsulated Zn-IONPs achieved up to 2.7-fold enhancement in MPI signal intensity compared to VivoTrax. Furthermore, these polymer encapsulated NPs were also determined to be non-toxic hence making these Zn-IONPs ideal for many biomedical applications in MPI where small size is critical to prolong circulation time and crossing the blood brain barrier

Optimization of callus and cell suspension cultures of Barringtonia racemosa (Lecythidaceae family) for lycopene production

Lycopene is present in a range of fresh fruits and vegetables, especially in the leaves of Barringtonia racemosa. The traditional lycopene extraction from the plant is being employed instead of an easy propagation technique like cell culture process from the leaf explants. We intend to assess how lycopene could be extracted via tissue culture under light (illuminance: 8,200 lux under white fluorescent lamps, photoperiod 16 h per day at 25ºC) and dark. Leaf explants of Barringtonia racemosa were cultured on modified Murashige and Skoog (MS), Woody Plant Medium (WPM) and B5 media, supplemented with different concentrations of 2,4-Dichlorophenoxyacetic acid (2,4-D). Optimal conditions for callus induction and maintenance under both dark and light were investigated, and growth and lycopene accumulation were evaluated. Among media with different concentrations of 2,4-D, fast growing, friable callus initiated within three weeks after culturing on WPM basal medium supplemented with 2.0 mg L-1 (weight per volume) of 2,4-D, whereas callus induction in explants cultured on all other media started only after five weeks. Calli were subcultured once every fortnight. Pale yellow and green calli developed under conditions of dark and light respectively were then selected for evaluation of their lycopene contents. An improved reversed phase of high performance liquid chromatography (HPLC) method was used for a selective chemical determination of the lycopene content. Light induced lycopene production; and likewise maximum lycopene level incubated in light was higher than those incubated in darkness. The best growth rates of callus and cell suspension were achieved in WPM and B5 media respectively. The production of lycopene was growth-dependent through analysis of growth and lycopene content of both callus and cell suspension cultures.O licopeno está presente numa série de frutas frescas e hortaliças principalmente na folhas de Barringtonia racemosa. A extração tradicional do licopeno tem sido empregada no lugar da fácil técnica de propagação como o processo de cultura de células de explantes de folhas. É nossa intenção demonstrar como o licopeno pode ser extraído através de cultura de tecido sob luz (iluminação com lâmpadas fluorescentes brancas de 8.200 lux, 16 h por dia a 25º C) e escuro. Explantes de folhas de Barringtonia racemosa foram cultivados em meio modificado de Murashige e Skoog (MS) para plantas lenhosas e meio B5, suplementado com diferentes concentrações de ácido 2,4-Diclorofenoxiacético (2,4-D). Condições ótimas para indução e manutenção de calos sob luz e escuro foram investigadas e avaliados o crescimento e acumulo de licopeno. Entre meios com diferentes concentrações de 2,4 -D, calos friáveis de crescimento rápido tiveram início em três semanas após serem cultivados em meio basal WPM suplementado com 2.0 mg L-1 (peso por volume) de 2,4-D enquanto indução de calos em explantes cultivados em todos os outros meios começaram somente após cinco semanas. Calos foram subrepicados a cada 15 dias. Calos amarelo-pálido e verdes desenvolvidos respectivamente sob condições escura e de luz foram então selecionados para avaliação do teor de licopeno. Um método aperfeiçoado de cromatografia líquida de alto desempenho foi usado para a determinação química seletiva do teor de licopeno. A produção de licopeno induzida sob luz e também o nível máximo de licopeno incubado em luz foi mais alto do que aqueles incubados no escuro. As melhores taxas de crescimento de calo e suspensões de células foram obtidas respectivamente em meio WPM e B5. A produção de licopeno dependeu do crescimento como demonstrado pela análise do crescimento e teor de licopeno de ambos calos e cultura de células em suspensão

Comparison of estimated human dose of 68Ga-MAA with 99mTc-MAA based on rat data

Objective: 99m Tc macroaggregated albumin (99m Tc- MAA) that had been used as a perfusion agent has been evaluated. In this study, we tried to estimate human absorbed dose of 68 Ga-MAA via commercially available kit from Pars-Isotopes, based on biodistribution data in wild-type rats, and compare our estimation with the available absorbed dose data from 99m Tc-MAA. Methods: For biodistribution of 68 Ga-MAA, three rats were sacrificed at each selected times after injection (15, 30, 45, 60, and 120 min) and the percentage of injected dose per gram of each organ was measured by direct counting from rats data from 11 harvested organs. The medical internal radiation dose formulation was applied to extrapolate from rats to human and to project the absorbed radiation dose for various organs in humans. Results: The biodistribution data for 68 Ga-MAA showed that the most of the activity was taken up by the lung (more than 97 %) in no time. Our dose prediction shows that a 185-MBq injection of 68 Ga-MAA into humans might result in an estimated absorbed dose of 4.31 mGy in the whole body. The highest absorbed doses are observed in the adrenals, spleen, pancreas, and red marrow with 0.36, 0.34, 0.26, and 0.19 mGy, respectively. Conclusion: Since the 99m Tc-MAA remains longer than 68 Ga-MAA in the lung and 68 Ga-MAA has good image qualities and results in lower amounts of dose delivery to the critical organs such as gonads, red marrow, and adrenals, the use of 68 Ga-MAA is recommended

Assessment of the effective absorbed dose of 4-benzyl-1-(3-[125I]-iodobenzylsulfonyl)piperidine in humans on the basis of biodistribution data of rats

Objectives: The aim of this study was to estimate the effective absorbed radiation dose to human organs following promising in-vivo results of intravenous administration of 4-benzyl-1-(3-[125I]-iodobenzylsulfonyl) piperidine (4-B-[125I]-IBSP) using normal biodistribution data obtained from rats. Materials and methods: Five rats were killed at exact time intervals and the percentage of injected dose per gram of each organ was measured by direct counting from rat data. The medical internal radiation dose formulation was applied to extrapolate from rats to humans and to project the absorbed radiation dose for various human organs. Results: The dose estimation shows that the organs that received the highest absorbed dose were the brain, bone surface, and red marrow (10.51, 0.69, and 0.08 μGy/MBq, respectively). Our prediction shows that a 185MBq injection of 4-B-[125I]-IBSP into humans might result in an estimated absorbed dose of 49.39 μGy for the whole body. The highest effective absorbed dose for 4-B-[125I]-IBSP was in the brain (19.4 μSv) and the organs that received the next highest doses were the bone surface, red marrow, muscle, and thyroid, with magnitudes of 15.27, 1.81, 0.15, and 0.10 μSv, respectively. Conclusion: The results of this study suggest that 4-B- [125I]-IBSP is a suitable and safe candidate in clinical studies and in lung malignancies

Determination of human absorbed dose of 201Tl(III)-DTPA-HIgG based on biodistribution data in rats

To estimate the absorbed dose in normal organs and inflammated tissue following i.v. administration of 201Tl(III)-DTPA-HIgG by using biodistribution data in inflammation-bearing rats was attempted. The percentages of injected dose per gram of each organ were calculated. The medical internal radiation dose formulation was applied to calculate the absorbed dose for various organs. The inflammated tissue to blood activity concentration ratios were about 19 and 23.3 at 24 and 28 h post-injection, respectively. A 185-MBq injection of 201Tl-DTPA-HIgG into the human body, might result in an estimated absorbed dose of 14.4 mGy for the total body and the highest absorbed dose was in the kidney with 1195 (mGy) and second to the Spleen were the liver, the lungs and the adrenals, which received 250.5 (mGy), 58.64 (mGy) and 56.44 (mGy), respectively. Biodistribution of 201Tl(III)-DTPA-HIgG demonstrated significant inflammated tissue uptake and low muscle and blood uptake, allowing for imaging of inflammated tissues. © The Author 2010. Published by Oxford University Press. All rights reserved

Comparison of estimated human effective dose of 67Ga- and 99mTc-labeled bombesin based on distribution data in mice

This study describes the preparation, biodistribution and absorbed dose prediction of 67Ga and 99mTc labeled bombesin (BBN) in human organs, after injection in mice determined via medical internal radiation dose. We estimated that a 185-MBq injection of 67Ga-BBN into the humans would result in an estimated effective absorbed dose of 2.50 mSv whereas this value for 99mTc-BBN is 1.33 mSv in the whole body. These results suggest that injection of 67Ga-BBN would result 2 times higher absorbed dose compare to 99mTc-BBN

Estimated human absorbed dose for 68Ga-ECC based on mice data : comparison with 67Ga-ECC

Objective: Nowadays, the efficacies of 68Ga-based tracers are comparable to that of 18F-based agents and have stimulated researchers to investigate the potential of 68Ga-based positron emission tomography (PET) imaging agents. In this study, the human absorbed dose of 68Ga labeled with ethylenecysteamine cysteine 68Ga-ECC and 67Ga-ECC was estimated based on biodistribution data in mice by the medical internal radiation dose (MIRD) method. Methods: For biodistribution of 67Ga/68Ga-ECC, three mice were killed by CO2 asphyxiation at each selected times after injection (15, 30, 45, 60, 120 min for 68Ga-ECC and 0.5, 2 and 48 h for 67Ga-ECC), and then the tissue (heart, lung, brain, intestine, skin, stomach, kidneys, liver, muscle and bone) was removed. Results: 68Ga-ECC as a new PET renal imaging agent was prepared with radiochemical purity of >97 % in less than 30 min. The biodistribution data for 68Ga-ECC showed that the most of the activity extracted from the urinary tract very fast. Comparison between human absorbed dose estimation for these two agents indicated that the absorbed dose of the most organs after injection of 67Ga-ECC is approximately tenfold higher than the amount after 68Ga-ECC injection. Conclusion: The results showed that 68Ga-ECC is a more appropriate agent rather than 67Ga-ECC and generally can be a good candidate for PET renal imaging applications