Simultaneous speciation analysis of Hg and Se in fish by high-performance liquid chromatography and inductively coupled plasma-mass spectrometry following microwave-assisted enzymatic hydrolysis.

This study reports the development and validation of a new analytical method for simultaneous speciation analysis of Se and Hg in fish muscle. For this purpose, four Se species (selenite/Se(IV), selenate/Se(VI), selenomethionine/SeMet, and selenocysteine/SeCys) and two Hg species (inorganic mercury/iHg and methylmercury/MeHg) were extracted simultaneously by microwave-assisted enzymatic hydrolysis and then separated by HPLC in less than 15 min by using a column with both anion and cation exchange mechanisms and a mobile phase consisting of a mixture of methanol 5% (v/v), 45 mM HNO3, 0.015% 2-mercaptoethanol, and 1.5 mM sodium 3-mercapto-1-propanesulfonate. The separated species of Hg and Se were detected online by inductively coupled plasma-mass spectrometry (ICP-MS). The speciation analysis method was validated by means of the accuracy profile approach by carrying out three series of measurements in duplicate on three different days over a time-span of 3 weeks. The limits of quantification (LOQ) are in the range of 0.010-0.013 mg/kg wet weight (ww) for all selenium species, except for Se(IV) (0.15 mg/kg ww), while the coefficient of variation in terms of intermediate reproducibility (CVR) was < 7%. The LOQ for MeHg was 0.006 mg/kg ww, while the CVR was 3%. The method was successfully applied to the analysis of muscle samples from four different fish species: rainbow trout, tuna, swordfish, and dogfish.

Assessment of the mercury-selenium antagonism in rainbow trout fish.

This study aims at the assessment of mercury (Hg)-selenium (Se) antagonism in fish. For this purpose, rainbow trout fish (Oncorhynchus mykiss) were exposed to methylmercury (MeHg) under controlled conditions, in the presence or absence of selenomethionine (SeMet) using an in-house prepared diet (enriched with MeHg and SeMet at 0.2 µg/g and 5.0 µg/g, respectively). The total duration of the exposure study was 3 months. Fish was sampled and analysed for total Se (SeT) and total mercury (HgT) content after 1, 2 and 3 months of exposure. Six feeding protocols were compared, depending on the exposure type: (i) no MeHg nor SeMet exposure (control group); (ii) exposure to SeMet solely; (iii) exposure to MeHg solely; (iv) exposure to both MeHg and SeMet; (v) exposure first to MeHg during 1 month and then to SeMet during 2 months and (vi), exposure to SeMet during 1 month and then to MeHg for 2 months. The levels of SeT and HgT in the fish (control and supplemented with MeHg/SeMet) were measured by inductively coupled plasma-mass spectrometry (ICPMS). Steadily (linear) bioaccumulation of MeHg in the fish muscle occurred when the fish were exposed individually to this species during the period. The bioaccumulation of MeHg is diminished when the fish are firstly exposed to SeMet and then to MeHg, hence indicating the MeHg detoxification due to SeMet supplementation.

Composition and bioaccessibility of elements in green seaweeds from fish pond aquaculture.

The elemental composition of five species of green seaweeds (Chaetomorpha linum, Rhizoclonium riparium, Ulva intestinalis, Ulva lactuca, Ulva prolifera) grown in fish pond aquaculture systems were studied. The elemental bioaccessibility in these species was also investigated through the application of an innovative in vitro digestive model of the human gastrointestinal tract. It was observed that R. riparium had the highest levels of Mn, Sr, Cd, Sn, and I and that U. lactuca had the highest Ni and Cu concentrations. The daily amounts of dried green seaweed required for achieving specific dietary intakes were calculated, namely: 7g of dried U. lactuca (for meeting Cu Recommended Daily Allowance, RDA); 173g of dried U. lactuca (Zn RDA); 78g of dried C. linum (Se RDA); 41g of dried C. linum (Mo RDA); and 0.5g of dried R. riparium (I Dietary Reference Intake, DRI). Concerning elemental bioaccessibility, Mn and Cu had the highest values, always above 50%, I values were in the lower range, between 14 and 31%. The elemental bioaccessibility range of R. riparium (31-100%) was higher than the ranges for other species, particularly C. linum (0-56%). The bioaccessibility results entailed higher quantities of dried seaweed for reaching dietary intakes: 10g of dried U. lactuca (Cu RDA); 290g of dried R. riparium (Zn RDA); and 2g of dried R. riparium (I DRI). Accordingly, R. riparium is a very rich I source. This study showed the importance of taking into account bioaccessibility results in estimating dietary intakes.

Quantitative imaging of platinum based on laser ablation-inductively coupled plasma-mass spectrometry to investigate toxic side effects of cisplatin.

This work presents a quantitative bioimaging method for platinum based on laser ablation-inductively coupled plasma-mass spectrometry and its application for a biomedical study concerning toxic side effects of cisplatin. To trace the histopathology back to cisplatin, platinum was localized and quantified in major functional units of testicle, cochlea, kidney, nerve and brain sections from cisplatin treated mice. The direct consideration of the histology enables precise interpretation of the Pt images and the novel quantitative evaluation approach allows significantly more precise investigations than the pure image. For the first time, platinum was detected and quantified in all major injured structures including organ of Corti of cochlea and seminiferous tubule of testicle. In this way, proximal tubule in kidney, Leydig cells in testicle, stria vascularis and organ of Corti in cochlea and nerve fibers in sciatic nerves are confirmed as targets of cisplatin in these organs. However, the accumulation of platinum in almost all investigated structures also raises questions about more complex pathogenesis including direct and indirect interruption of several biological processes.

Evaluation of the risk/benefit associated to the consumption of raw and cooked farmed meagre based on the bioaccessibility of selenium, eicosapentaenoic acid and docosahexaenoic acid, total mercury, and methylmercury determined by an in vitro digestion model.

The bioaccessibility of total lipids, EPA, DHA, Se, Hg, and MeHg in raw and cooked meagre (Argyrosomus regius) was studied by using an in vitro digestion method. A risk-benefit assessment of raw and cooked meagre on the basis of the bioaccessibility data was carried out. The bioaccessibility of total lipids was generally high in raw and cooked meagre with exception of grilled fish. For EPA and DHA, bioaccessibility percentages were low never surpassing the 50% in raw, boiled, and grilled meagre. The bioaccessibility percentage of Se was equal or higher than 82% (grilling treatment). Likewise, for Hg and MeHg, high bioaccessibility values were determined with exception of grilled meagre, displaying lower values of 54% and 64%, respectively. The risk-benefit probabilistic assessment brought about a recommendation of a maximum consumption of two weekly meals for boiled or roasted meagre and three weekly meals for grilled meagre.

Portuguese food composition database quality management system.

BACKGROUND: The harmonisation of food composition databases (FCDB) has been a recognised need among users, producers and stakeholders of food composition data (FCD). To reach harmonisation of FCDBs among the national compiler partners, the European Food Information Resource (EuroFIR) Network of Excellence set up a series of guidelines and quality requirements, together with recommendations to implement quality management systems (QMS) in FCDBs. The Portuguese National Institute of Health (INSA) is the national FCDB compiler in Portugal and is also a EuroFIR partner. INSA's QMS complies with ISO/IEC (International Organization for Standardisation/International Electrotechnical Commission) 17025 requirements. The purpose of this work is to report on the strategy used and progress made for extending INSA's QMS to the Portuguese FCDB in alignment with EuroFIR guidelines. SUBJECTS/METHODS: A stepwise approach was used to extend INSA's QMS to the Portuguese FCDB. The approach included selection of reference standards and guides and the collection of relevant quality documents directly or indirectly related to the compilation process; selection of the adequate quality requirements; assessment of adequacy and level of requirement implementation in the current INSA's QMS; implementation of the selected requirements; and EuroFIR's preassessment 'pilot' auditing. RESULTS: The strategy used to design and implement the extension of INSA's QMS to the Portuguese FCDB is reported in this paper. The QMS elements have been established by consensus. ISO/IEC 17025 management requirements (except 4.5) and 5.2 technical requirements, as well as all EuroFIR requirements (including technical guidelines, FCD compilation flowchart and standard operating procedures), have been selected for implementation. The results indicate that the quality management requirements of ISO/IEC 17025 in place in INSA fit the needs for document control, audits, contract review, non-conformity work and corrective actions, and users' (customers') comments, complaints and satisfaction, with minor adaptation. Implementation of the FCDB QMS proved to be a way of reducing the subjectivity of the compilation process and fully documenting it, and also facilitates training of new compilers. Furthermore, it has strengthened cooperation and trust among FCDB actors, as all of them were called to be involved in the process. CONCLUSIONS: On the basis of our practical results, we can conclude that ISO/IEC 17025 management requirements are an adequate reference for the implementation of INSA's FCDB QMS with the advantages of being well known to all members of staff and also being a common quality language among laboratories producing FCD. Combining quality systems and food composition activities endows the FCDB compilation process with flexibility, consistency and transparency, and facilitates its monitoring and assessment, providing the basis for strengthening confidence among users, data producers and compilers.

Development of an analytical method for the determination of photoinitiators used for food packaging materials with potential to migrate into milk.

Photoinitiators are used in the curing process during UV printing of food carton labels. The alarm concerning the detection of a photoinitiator, 2-isopropyl thioxanthone (ITX), in food samples packed with cartons printed with UV-cured inks has focused the attention of legislative authorities on the potential migrants from packaging inks into foods. For this reason it is very important to carry out analytical methods for the detection of those compounds in food as potential migrants from packaging. The aim of the present work was to develop a multimethod for the analysis of 6 photoinitiators in milk. The selected photoinitiators were Irgacure 184, benzophenone, Irgacure 651, Irgacure 907, Quantacure ITX, and Quantacure EHA (2-ethylhexyl-4-dimethylaminobenzoate). Milk (10 mL) extraction was carried out by using ammoniac and hexane. The supernatant was evaporated and the residue was redissolved with acetonitrile. Then, the extract was analyzed by HPLC-UV. Calibration lines were carried out over the concentration range of 0.1 to 10 mg/L. The calibration data presented high correlation coefficients (>0.9999). Mean recoveries (n = 6) of the 6 photoinitiators were 83.4% (residual standard deviation = 2.3%) at 0.5 mg/kg and 81.0% (residual standard deviation = 4.6%) at 1 mg/kg. Several milk samples and their respective packaging cartons were analyzed. Results were confirmed by HPLC-mass spectrometry.

[Food poisoning outbreak caused by Salmonella Enteritidis in the northwest of São Paulo State, Brazil]. / Surto alimentar por Salmonella Enteritidis no Noroeste do Estado de São Paulo, Brasil.

A foodborne outbreak which affected 211 persons occurred, in a School, in 1993. The epidemiological data obtained by interviewing the affected and non affected persons sampled showed as predominant symptoms: diarrhoea, fever (77.7%), abdominal cramps (67.7%), vomiting (65.8%), hot-and-cold sensations (54.5%) and headache (44.5%). The median incubation period was of 17 hours, the limits being 3 and 29 hours. The disease period was of from 3 to 4 days. The food concerned was a kind of paté, a mayonnaise mixture prepared with fresh eggs with boiled potatoes that was consumed with bread. The biological material analysis-3 coprocultures, and leftovers of the food revealed the presence of one and the same organism: Salmonella Enteritidis. In the food, the numbers of this bacterium per gram were sufficient to account for the manifestation of the disease (10(4) and 10(5)g). The antibiogram of all th isolates showed the same sensibility pattern. The preparation related to this outbreak suggests the endogenous contamination of the eggs; the cross contamination-the outbreak affected three school periods, as the food was prepared separately for each school period; and the conditions under which the food was kept during the time from preparation to consumption. The observation of the 3 food handlers, by successive coprocultures, for one week, indicates that they were not asymptomatic carriers nor were they affected as a result of this outbreak by the causal bacteria.

Surto alimentar por Salmonella Enteritidis no Noroeste do Estado de Säo Paulo, Brasil / Outbreak of Salmonella Enteritidis in northwest of S. Paulo State, Brazil

Em 1993 ocorreu um surto alimentar em escola, com 211 afetados. Os dados epidemiológicos levantados por entrevista de amostragem de afetados e näo afetados mostraram que os sintomas predominantes foram diarréia, febre (77,7 porcento), dor abdominal (67,7 porcento) e vômito (65,8 porcento), calafrios (54,5 porcento) e cefaléia (44,5 porcento). A mediana de incubaçäo foi de 17 horas, com limites entre 3 e 29 horas. A duraçäo da doença foi de 3 a 4 dias. O alimento consumido foi um tipo de patê, mistura de molho de maionese preparada com ovos crus com batata cozida, passado em päo. A análise de material biológico (3 coproculturas) e de restos de alimentos, revelou a presença do mesmo microorganismo, a Salmonella Enteritidis. No caso dos alimentos, o núnero encontrado desta bactéria por gramo de produto era compatível com a quantidade de células necessária para desencadear a doença (10*4 e 10*5/g). O antibiograma de todas as cepas isoladas revelou o mesmo padräo de sensibilidade. As falhas no preparo de alimento relacionadas com o levantamento indicam a possibilidade de contaminaçäo endógena dos ovos; contaminaçäo cruzada - o surto afetou três períodos escolares, sendo que para cada um o alimento foi preparado em separado - e as condiçöes de manutençäo do alimento após preparo e até o consumo. A observaçäo por uma semana seguida das 3 merendeiras envolvidas, através de coprocultura, näo indicaram que as mesmas fossem portadoras assintomáticas desta bactéria ou que tivessem sido envolvidas no surto em questäo

Preparation and biological characteristics of 99mTc-diol a renal agent.

The present work concerns the production of 1,2-dihydroxypropyl-1-phosphonic acid (diol) by acid hydrolysis of (-cis) 1,2-epoxypropylphosphonic acid (phosphomycin), and its formulation as a kit easily labeled with [99mTc]pertechnetate. Biodistribution studies and whole-body autoradiographies in mice show that 99mTc-diol has a specific affinity for the kidneys: it is rapidly cleared from the blood and excreted in urine (12.09 +/- 6.40% ID are excreted in urine at 5 min and 70.81 +/- 2.41% ID at 30 min post-injection). Part of the injected activity remains in the kidney cortex sufficiently long to permit kidney imaging (5.66 +/- 0.91% ID is still in kidneys 1 h post-injection). In comparison with other agents which also localize in the kidney cortex, such as 99mTc-DMSA and 99mTc-glucoheptonate (99mTc-GHA), the main differences are the following: the peak of renal activity is reached early in the 5 min post-injection period for 99mTc-diol, only at about 10 min post-injection for 99mTc-GHA and after 3 h post-injection for 99mTc-DMSA. The uptake of 99mTc-diol by other organs, especially by bones, is much smaller than in the case of 99mTc-DMSA (1.25 +/- 0.11% ID of 99mTc-diol compared to 11.31 +/- 1.17% ID of 99mTc-DMSA, 1 h post-injection). Unlike 99mTc-DMSA, the biodistribution of 99mTc-diol is not significantly influenced by acid-base imbalance, in addition, its renal uptake decreases in the presence of probenecid whereas its urinary excretion increases.(ABSTRACT TRUNCATED AT 250 WORDS)

Complexes of technetium-99m with phosphomycin, obtained by pH shifting: biological characteristics, whole-body autoradiography, gamma-camera study.

Phosphomycin (phos), a large spectrum antibiotic with preferential localization into the kidneys, can be labeled with technetium-99m at various pHs. However, the final pH in the labeling of phos by [99mTc]pertechnetate in the presence of SnCl2 seems to play a significant role in determining the biological properties of the final labeled product. Radiopharmacological characteristics of various forms of 99mTc-phos obtained at pHs 6.8, 4.5 and 2.5 were studied in mice, rats and rabbits. Significant differences in these products were shown by biodistribution studies in Balb/C mice and Wistar rats and confirmed by whole-body autoradiographies in mice and gamma-camera studies in rats and rabbits. 99mTc-phos, pH 6.8, has a high uptake in kidneys from 2 min after injection (10.25 +/- 1.11 %ID) to 3 h after injection (8.26 +/- 0.42 %ID) and a rapid urinary excretion (19.9 +/- 7.35 %ID at 2 min after injection and 75.11 +/- 3.48 %ID at 3 h). Intrarenal pharmacokinetics studied by autoradiography showed a high concentration in the inner medulla and pelvis at 1 min after injection followed by an increased localization in kidney cortex, like 99mTc-DMSA. Preferential uptake in bones was shown by 99mTc-phos, pH 2.5, from 5 min to 3 h after injection (15.05 +/- 2.67 %ID at 3 h compared to 1.79 +/- 0.19 %ID of 99mTc-phos, pH 6.8, at the same time). A high urinary excretion of 99mTc-phos, pH 2.5, is shown as in the case of other bone agents (76.5 +/- 3.46 %ID at 3 h post-injection) but without any kidney retention (1.80 +/- 0.26 %ID in kidneys 3 h post-injection).(ABSTRACT TRUNCATED AT 250 WORDS)

Renal gammagraphy with 99mTc-phosphomycin.

99mTc-Phosphomycin, a new radiopharmaceutical for kidney visualization, was used for animal experiments and tests of 171 patients. The results confirmed the usefulness of this product. The ease and yield of the labelling procedure, the low cost of the product, the excellent quality of the images and the functional information obtained showed that the use of 99mTc-phosphomycin as a radiopharmaceutical for kidney visualization has many advantages.