Ezeiza Atomic Center

Puerto Rico, Argentina

Ezeiza Atomic Center

Puerto Rico, Argentina
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Hevia S.,Dalhousie University | Hevia S.,Ezeiza Atomic Center | Hevia S.,Petro Canada | Resnizky S.,Ezeiza Atomic Center | Chatt A.,Dalhousie University
Journal of Radioanalytical and Nuclear Chemistry | Year: 2013

The selenium levels of Argentinean infant formulae and baby food were measured using the 162-keV gamma-ray of 77mSe (t1/2 = 17.4 s) by a pseudo-cyclic instrumental neutron activation analysis (PC-INAA) method in conjunction with Compton suppression spectrometry (CSS). For comparison purposes, 5 selected infant formulae were also analyzed for selenium by a radiochemical neutron activation analysis (RNAA) method. The selenium levels for three samples agreed between ±2.8 and 6.5 % while the other two differed by 12 and 17 % which could perhaps be attributed to sample inhomogeneity. The selenium content of cow milk-based infant formulae varied from 42-146 μg kg-1 compared to 52-63 μg kg-1 for soy-based milk formulae. In the case of baby foods, the selenium levels varied from 34 to 74 μg kg-1. The detection limits for selenium by PC-INAA-CSS for all the samples analyzed in this work were between 8.5 and 65 μg kg-1 depending on the major elements present in the samples, while it was 20 μg kg-1 for the RNAA method. The expanded uncertainty (κ = 2) of the PC-INAA-CSS method was 7.0 % at the end of cycle #4 for a sample containing 73.7 μg kg-1 selenium compared to the RNAA value of 24.2 % for a sample of 67.0 μg kg-1 selenium content. © 2012 Akadémiai Kiadó, Budapest, Hungary.

Narvaiz P.,Ezeiza Atomic Center
Stewart Postharvest Review | Year: 2015

Purpose of the review: It is well-known that ionizing irradiation, as well as other preservation methods, extends food shelf life and controls microbial food-borne diseases. But it is not so evident that due to some peculiar characteristics (eg, high penetration - cold process) it can achieve better results in assuring the safety of ready-to-eat meals formulated for different consumers, ie, the immunocompromised, troops, astronauts, or adventurers. Main findings: In some countries hospitalized immunocompromised patients have been fed with ready-to-eat meals irradiated at doses according to "clean diet" criteria, and these foods have obtained good sensory acceptability. This has allowed widening of food variety, thereby increasing the nutritional value of their intake. Similar findings were also reported concerning foods used for astronauts, troops and adventurers. Research is still ongoing in the field. However, today, these applications, though promising, seem to be occurring on a small scale. Directions for future research: Cooperation between food irradiation researchers, nutritionists and physicians is essential to develop and improve new applications. Minimizing radiation doses might be feasible if it is combined with other hurdle technologies. More disclosure is needed mainly directed towards nutritionists, physicians, patients, and the staff of health institutes, catering services, food industry, supermarkets, and the general public. The establishment of national regulations related to this activity, hopefully internationally harmonized, are certainly needed, as well as availability of more food irradiation facilities. © 2015 SPS (UK) Ltd.

Monti Hughes A.,National Atomic Energy Commission | Pozzi E.C.C.,National Atomic Energy Commission | Pozzi E.C.C.,Ezeiza Atomic Center | Heber E.M.,National Atomic Energy Commission | And 13 more authors.
Oral Oncology | Year: 2011

Given the clinical relevance of locoregional recurrences in head and neck cancer, we developed a novel experimental model of premalignant tissue in the hamster cheek pouch for long-term studies and demonstrated the partial inhibitory effect of a single application of Boron Neutron Capture Therapy (BNCT) on tumor development from premalignant tissue. The aim of the present study was to evaluate the effect of a double application of BNCT with a 6 week interval in terms of inhibitory effect on tumor development, toxicity and DNA synthesis. We performed a double application, 6 weeks apart, of (1) BNCT mediated by boronophenylalanine (BPA-BNCT); (2) BNCT mediated by the combined application of decahydrodecaborate (GB-10) and BPA [(GB-10 + BPA)-BNCT] or (3) beam-only, at RA-3 nuclear reactor and followed the animals for 8 months. The control group was cancerized and sham-irradiated. BPA-BNCT, (GB-10 + BPA)-BNCT and beam-only induced a reduction in tumor development from premalignant tissue that persisted until 8, 3, and 2 months respectively. An early maximum inhibition of 100% was observed for all 3 protocols. No normal tissue radiotoxicity was detected. Reversible mucositis was observed in premalignant tissue, peaking at 1 week and resolving by the third week after each irradiation. Mucositis after the second application was not exacerbated by the first application. DNA synthesis was significantly reduced in premalignant tissue 8 months post-BNCT. A double application of BPA-BNCT and (GB-10 + BPA)-BNCT, 6 weeks apart, could be used therapeutically at no additional cost in terms of radiotoxicity in normal and dose-limiting tissues. © 2011 Elsevier Ltd. All rights reserved.

Molinari A.J.,Constituyentes Atomic Center | Pozzi E.C.C.,Constituyentes Atomic Center | Pozzi E.C.C.,Research and Production Reactors | Hughes A.M.,Constituyentes Atomic Center | And 13 more authors.
Radiation Research | Year: 2011

In the present study the therapeutic effect and potential toxicity of the novel "“Sequential"†boron neutron capture therapy (Seq-BNCT) for the treatment of oral cancer was evaluated in the hamster cheek pouch model at the RA-3 Nuclear Reactor. Two groups of animals were treated with "Sequential"BNCT, i.e., BNCT mediated by boronophenylalanine (BPA) followed by BNCT mediated by sodium decahydrodecaborate (GB-10) either 24 h (Seq-24h-BNCT) or 48 h (Seq-48h-BNCT) later. In an additional group of animals, BPA and GB-10 were administered concomitantly [(BPA + GB-10)-BNCT]. The single-application BNCT was to the same total physical tumor dose as the "Sequential"BNCT treatments. At 28 days post-treatment, Seq-24h-BNCT and Seq-48h-BNCT induced, respectively, overall tumor responses of 95 ±2% and 91 ±3%, with no statistically significant differences between protocols. Overall response for the single treatment with (BPA + GB-10)-BNCT was 75 ±5%, significantly lower than for Seq-BNCT. Both Seq-BNCT protocols and (BPA + GB-10)-BNCT induced reversible mucositis in the dose-limiting precancerous tissue around treated tumors, reaching Grade 3/4 mucositis in 47 ±12% and 60 ±22% of the animals, respectively. No normal tissue toxicity was associated with tumor response for any of the protocols. "Sequential"BNCT enhanced tumor response without an increase in mucositis in dose-limiting precancerous tissue. © 2011 by Radiation Research Society. All rights of reproduction in any form reserved.

Gliemmo M.F.,University of Buenos Aires | Gliemmo M.F.,CONICET | Latorre M.E.,University of Buenos Aires | Latorre M.E.,CONICET | And 5 more authors.
Food Science and Technology International | Year: 2014

The effect of gamma irradiation (0-2 kGy) and storage time (0-28 days) on microbial growth and physicochemical characteristics of a packed pumpkin puree was studied. For that purpose, a factorial design was applied. The puree contained potassium sorbate, glucose and vanillin was stored at 25°. Gamma irradiation diminished and storage time increased microbial growth. A synergistic effect between both variables on microbial growth was observed. Storage time decreased pH and color of purees. Sorbate content decreased with storage time and gamma irradiation. Mathematical models of microbial growth generated by the factorial design allowed estimating that a puree absorbing 1.63 kGy would have a shelf-life of 4 days. In order to improve this time, some changes in the applied hurdles were assayed. These included a thermal treatment before irradiation, a reduction of irradiation dose to 0.75 kGy and a decrease in storage temperature at 20 °. As a result, the shelf-life of purees increased to 28 days. © 2012 The Author(s).

Molinari A.J.,Constituyentes Atomic Center | Pozzi E.C.C.,Constituyentes Atomic Center | Pozzi E.C.C.,Ezeiza Atomic Center | Hughes A.M.,Constituyentes Atomic Center | And 10 more authors.
Radiation Research | Year: 2012

We previously demonstrated the efficacy of BNCT mediated by boronophenylalanine (BPA) to treat tumors in a hamster cheek pouch model of oral cancer with no normal tissue radiotoxicity and moderate, albeit reversible, mucositis in precancerous tissue around treated tumors. It is known that boron targeting of the largest possible proportion of tumor cells contributes to the success of BNCT and that tumor blood vessel normalization improves drug delivery to the tumor. Within this context, the aim of the present study was to evaluate the effect of blood vessel normalization on the therapeutic efficacy and potential radiotoxicity of BNCT in the hamster cheek pouch model of oral cancer. Blood vessel normalization was induced by two doses of thalidomide in tumor-bearing hamsters on 2 consecutive days. All studies in thalidomide-treated animals were performed 48 h after the first dose of thalidomide, previously established as the window of normalization. Biodistribution studies were performed with BPA at a dose of 15.5 mg 10B/kg in thalidomide-treated (Th+) and untreated (Th) tumor-bearing hamsters. The effect of blood vessel normalization prior to BPA administration on the efficacy of BNCT was assessed in in vivo BNCT studies at the RA-3 Nuclear Reactor in tumor-bearing hamsters. Group I was treated with BPA-BNCT after treatment with thalidomide (Th+ BPA-BNCT). Group II was treated with BPA-BNCT alone (Th BPA-BNCT). Group III was treated with the beam only after treatment with thalidomide (Th+ BO), and Group IV was treated with the beam only (Th BO). Groups I and II were given the same dose of BPA (15.5 mg 10B/kg), and all groups (IIV) were exposed to the same neutron fluence. Two additional groups were treated with the beam only at a higher dose to exacerbate mucositis in precancerous tissue and to explore the potential direct protective effect of thalidomide on radiation-induced mucositis in a scenario of more severe toxicity, i.e. Group V (Th+ hdBO) and Group VI (Th hdBO). The animals were followed for 28 days. Biodistribution studies revealed no statistically significant differences in gross boron content between Th+ and Th animals. Overall tumor control (complete response + partial response) at 28 days post-treatment was significantly higher for Group I (Th+ BPA-BNCT) than for Group II (Th BPA-BNCT): 84 ± 3% compared to 67 ± 5%. Pretreatment with thalidomide did not induce statistically significant changes in overall tumor control induced by the beam only, i.e. 15 ± 5% in Group III (Th+ BO) and 18 ± 5% in Group IV (Th BO), or in overall tumor control induced by the high-dose beam only, i.e. 60 ± 7% in Group V (Th+ hdBO) and 47 ± 10% in Group VI (Th hdBO). BPA-BNCT alone (Group II) induced mucositis in precancerous tissue that reached Grades 34 in 80% of the animals, whereas pretreatment with thalidomide (Group I) prevented mucositis Grades 3 and 4 completely. Beam-only Group III (Th+ BO) exhibited only Grade 1 mucositis in precancerous tissue, whereas 17% of the animals in beam-only Group IV (Th BO) reached Grade 2 mucositis. High-dose beam-only group V (Th+ hdBO) exhibited only Grade 2 mucositis, whereas high-dose beam-only group VI (Th hdBO) reached Grade 3 mucositis in 83% of the animals. In all cases mucositis in precancerous tissue was reversible. No normal tissue radiotoxicity was observed with any of the protocols. Pretreatment with thalidomide enhanced the therapeutic efficacy of BNCT and reduced precancerous tissue toxicity. © 2012 by Radiation Research Society.

Latorre M.E.,University of Buenos Aires | Narvaiz P.,Ezeiza Atomic Center | Rojas A.M.,University of Buenos Aires | Gerschenson L.N.,University of Buenos Aires
Journal of Food Engineering | Year: 2010

Red beet (Beta vulgaris L. var. conditiva) root is a popular item present in ready to eat salads and minimally processed foods. In this research, the effect of low doses of gamma radiation (1 and 2 kGy) on peroxidase (POX), polyphenol oxidase (PPO) and phenylalanine ammonia-lyase (PAL) activities, as well as on the levels of compounds related to the response to the oxidative stress of plant metabolism, the changes in colour and the mechanical behaviour of fresh-cut red beet root were analyzed, with the purpose of understanding the influence of the processing on tissue characteristics. Cell wall modifications were also studied through sequential extractions of polysaccharides from the alcohol-insoluble residues (AIR) obtained from each tissue. Irradiation seemed to contribute to higher cell-cell adhesion through increasing of calcium-cross linking at the middle lamellae regions, in addition to an increment of cross-links of polymers into the cell wall. Chemical modifications produced in the cell walls as a response to higher levels of H2O2 and subsequent POX mediated effects, were visualized structurally as a more elastic behaviour of irradiated tissues and rigidification of cell walls of treated roots, though puncture test did not reveal significant differences. Microscopy showed a continuum of thick cell walls in beet root tissue, which suffered slight modifications after irradiation, coherent with the bio-chemical results obtained. It can be concluded that irradiation doses of 1 or 2 kGy produced bio-chemical changes in cellular contents as well as in the cell wall constitutive networks which not necessarily could be sensed by consumers as it was objectively evaluated through a puncture test. At the same time, the mentioned changes involved an increase in the antioxidant capacity of red beet root tissue, showing that studied doses could be interesting to be used in the frame of a combined technique for red beet processing. © 2009 Elsevier Ltd. All rights reserved.

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