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BACKGROUND: The tonsils operate as a protection ring of mucosa at the gates of the upper aero-digestive tract. They show similarities with lymph nodes and participate as inductive organs of systemic and mucosal immunity. Based on the reduction of their size since puberty, they are thought to experience involution in adulthood. In this context, we have used tonsillar mononuclear cells (TMC) isolated from patients at different stages of life, to study the effect of ageing and the concomitant persistent inflammation on these immune cells. RESULTS: We found an age-dependent reduction in the proportion of germinal center B cell population (BGC) and its T cell counterpart (T follicular helper germinal center cells, TfhGC). Also, we demonstrated an increment in the percentage of local memory B cells and mantle zone T follicular helper cells (mTfh). Furthermore, younger tonsils rendered higher proportion of proliferative immune cells within the freshly isolated TMC fraction than those from older ones. We demonstrated the accumulation of a B cell subset (CD20+CD39highCD73+ cells) metabolically adapted to catabolize adenosine triphosphate (ATP) as patients get older. To finish, tonsillar B cells from patients at different ages did not show differences in their proliferative response to stimulation ex vivo, in bulk TMC cultures. CONCLUSIONS: This paper sheds light on the changing aspects of the immune cellular landscape, over the course of time and constant exposure, at the entrance of the respiratory and digestive systems. Our findings support the notion that there is a re-modelling of the immune functionality of the excised tonsils over time. They are indicative of a transition from an effector type of immune response, typically oriented to reduce pathogen burden early in life, to the development of an immunosuppressive microenvironment at later stages, when tissue damage control gets critical provided the time passed under immune attack. Noteworthy, when isolated from such histologic microenvironment, older tonsillar B cells seem to level their proliferation capacity with the younger ones. Understanding these features will not only contribute to comprehend the differences in susceptibility to pathogens among children and adults but would also impact on vaccine developments intended to target these relevant mucosal sites.

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As a consequence of the limited resources of underdeveloped countries and the limited interest of the developed ones, the assessment of the chemical quality of entire water bodies around the world is a utopia in the near future. The methodology described here may serve as a first approach for the fast identification of water bodies that do not meet the good chemical status demanded by the European Water Framework Directive (WFD). It also allows estimating the natural background (or reference values of concentration) of the areas under study using a simple criterion. The starting point is the calculation the World-Wide Natural Background Levels (WWNBLs) and World-Wide Threshold Values (WWTVs), two indexes that depend on the concentration of seven elements present in sediments. These elements, As, Cd, Cr, Cu, Ni, Pb and Zn, have been selected taking into account the recommendations of the UNEP (United Nations Environment Programme) and USEPA (United States Environmental Protection Agency), that describe them as elements of concern with respect to environmental toxicity. The methodology has been exemplified in a case study that includes 134 sediment samples collected in 11 transitional water bodies from 7 different countries and 4 different continents. Six of the water bodies considered met the good chemical status demanded by the WFD. The rest of them exceeded the reference WWTVs, at least for one of the elements. The estuaries of the Nerbioi-Ibaizabal (Basque Country) and Cavado (Portugal), the sea inlet of Río San Pedro (Spain), the Sepetiba Bay (Brazil) and the Yucateco lagoon (Mexico) belong to that group.

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La obesidad es la causa más común de insulinorresistencia en niños y adolescentes. La misma presenta un aumento de su prevalencia involucrando a todos los grupos etarios. La insulinorresistencia determina disturbios metabólicos que son deletéreos para el árbol vascular y otros tejidos. Además se demostró una asociación entre insulinorresistencia e hiperinsulinemia con mayor prevalencia de nódulos tiroideos y aumento del tamaño de la tiroides, que estaría relacionado a la acción bociógena de la insulina y el IGF-1. El objetivo fue evaluar la prevalencia de factores de riesgo cardiovasculares, la presencia de esteatosis hepática y su asociación con hiperinsulinismo. Realizamos un estudio transversal descriptivo de 75 niños entre 2 y 14 años que consultaron al Servicio de Endocrinología en un lapso de 14 meses. Se analizaron las siguientes variables: peso, talla, índice de masa corporal (IMC), glucemia, insulinemia, índice HOMA, acantosis nigricans, transaminasas hepáticas, perfil lipídico, cortisol 8 hs, perfil tiroideo con anticuerpos, ecografía tiroidea y abdominal. Encontramos que 60% de la población presentó niveles de insulina elevados (>15 AUI/ml) con aumento progresivo de la prevalencia de acantosis nigricans, el 12,3% tuvo glucemias alteradas de ayuno y 66,6% índice HOMA >3. El 90% de los pacientes con ecografía tiroidea heterogénea presentó hiperinsulinismo (p <0,05), hallándose nódulos tiroideos en 5 (9,8%) de ellos. Evaluamos la posible relación entrenódulos tiroideos e hiperinsulinismo, y encontramos una asociación positiva en el 80%. La obesidad infantil debeser considerada un problema de salud pública.(AU)

Obesity is the most common cause of insulin resistance in children and adolescents. It has increasing prevalence and involves all age groups. Insulin resistance determines metabolic disturbances that are deleterious to the vasculature and other tissues. An association between insulin resistance and hyperinsulinemia on the one side and increased prevalence of thyroidnodules and enlargement of the thyroid gland on the other has been demonstrated, which could be related to the goitrogenic action of insulin and IGF-1. The aim of this study was to evaluate the prevalence of cardiovascular risk factors, the presence of hepatic steatosis and its association with hyperinsulinism. We performed a cross sectional study of 75 childrenbetween 2 and 14 years (mean 10 years) who visited the Department of Endocrinology during a span of 14 months.We analyzed the following variables: weight, height, body mass index (BMI), glucose, insulin, HOMA, acanthosis nigricans, liver transaminases, lipid profile, cortisol at 8 AM, thyroid function tests and thyroid antibodies, thyroid and abdominalultrasonography. In our study we found that 60% of the population showed elevated insulin levels (>15 ýIU/ml) with progressive increase in the prevalence of acanthosis nigricans, and 12.3% showed inappropriate glucose levels. Ninety per cent of patients with heterogeneous thyroid ultrasonography had hyperinsulinemia (p <0.05), and thyroid nodules were found in 5 of them (9.8%). We assessed the possible relationship between thyroid nodules and hyperinsulinism, and founda positive association in 80% of the cases. Childhood obesity should be considered a public health problem.(AU)

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La obesidad es la causa más común de insulinorresistencia en niños y adolescentes. La misma presenta un aumento de su prevalencia involucrando a todos los grupos etarios. La insulinorresistencia determina disturbios metabólicos que son deletéreos para el árbol vascular y otros tejidos. Además se demostró una asociación entre insulinorresistencia e hiperinsulinemia con mayor prevalencia de nódulos tiroideos y aumento del tamaño de la tiroides, que estaría relacionado a la acción bociógena de la insulina y el IGF-1. El objetivo fue evaluar la prevalencia de factores de riesgo cardiovasculares, la presencia de esteatosis hepática y su asociación con hiperinsulinismo. Realizamos un estudio transversal descriptivo de 75 niños entre 2 y 14 años que consultaron al Servicio de Endocrinología en un lapso de 14 meses. Se analizaron las siguientes variables: peso, talla, índice de masa corporal (IMC), glucemia, insulinemia, índice HOMA, acantosis nigricans, transaminasas hepáticas, perfil lipídico, cortisol 8 hs, perfil tiroideo con anticuerpos, ecografía tiroidea y abdominal. Encontramos que 60% de la población presentó niveles de insulina elevados (>15 µUI/ml) con aumento progresivo de la prevalencia de acantosis nigricans, el 12,3% tuvo glucemias alteradas de ayuno y 66,6% índice HOMA >3. El 90% de los pacientes con ecografía tiroidea heterogénea presentó hiperinsulinismo (p <0,05), hallándose nódulos tiroideos en 5 (9,8%) de ellos. Evaluamos la posible relación entrenódulos tiroideos e hiperinsulinismo, y encontramos una asociación positiva en el 80%. La obesidad infantil debeser considerada un problema de salud pública.

Obesity is the most common cause of insulin resistance in children and adolescents. It has increasing prevalence and involves all age groups. Insulin resistance determines metabolic disturbances that are deleterious to the vasculature and other tissues. An association between insulin resistance and hyperinsulinemia on the one side and increased prevalence of thyroidnodules and enlargement of the thyroid gland on the other has been demonstrated, which could be related to the goitrogenic action of insulin and IGF-1. The aim of this study was to evaluate the prevalence of cardiovascular risk factors, the presence of hepatic steatosis and its association with hyperinsulinism. We performed a cross sectional study of 75 childrenbetween 2 and 14 years (mean 10 years) who visited the Department of Endocrinology during a span of 14 months.We analyzed the following variables: weight, height, body mass index (BMI), glucose, insulin, HOMA, acanthosis nigricans, liver transaminases, lipid profile, cortisol at 8 AM, thyroid function tests and thyroid antibodies, thyroid and abdominalultrasonography. In our study we found that 60% of the population showed elevated insulin levels (>15 ìIU/ml) with progressive increase in the prevalence of acanthosis nigricans, and 12.3% showed inappropriate glucose levels. Ninety per cent of patients with heterogeneous thyroid ultrasonography had hyperinsulinemia (p <0.05), and thyroid nodules were found in 5 of them (9.8%). We assessed the possible relationship between thyroid nodules and hyperinsulinism, and founda positive association in 80% of the cases. Childhood obesity should be considered a public health problem.

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The objectives of the present study were (1) to compare the relative importance of price, processing time, texture and intramuscular fat in purchase intention of dry-cured ham through conjoint analysis, (2) to evaluate the effect of dry-cured ham appearance on consumer expectations, and (3) to describe the consumer sensory preferences of dry-cured ham using external preference mapping. Texture and processing time influenced the consumer preferences in conjoint analysis. Red colour intensity, colour uniformity, external fat and white film presence/absence influenced consumer expectations. The consumer disliked hams with bitter and metallic flavour and with excessive saltiness and piquantness. Differences between expected and experienced acceptability were found, which indicates that the visual preference of consumers does not allow them to select a dry-cured ham that satisfies their sensory preferences of flavour and texture.

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Los objetivos del estudio fueron determinar la prevalencia de psoriasis en pacientes con Artritis Reumatoidea (AR) tratados con Agentes Biológicos (AB) y analizar sus características clínicas en una población de Tucumán.Se incluyeron 284 pacientes con AR. Ciento cuarenta y ocho en tratamiento con AB y 136 pacientes en tratamiento con Drogas Modificadoras de AR (DMAR), seleccionados por muestreo aleatorio simple. De los 284 pacientes evaluados, 242 (85%) fueron de sexo femenino, edad media de 56,4 años ± 13,4, la edad media al diagnóstico de AR fue de 42,3 años ± 16,7 con un tiempo de evolución de la enfermedad de 11,9 años ± 8,5. Doscientos cuarenta y un pacientes (85%) fueron seropositivos para Factor Reumatoideo (FR). Ciento treinta y seis (48%) fueron tratados con DMAR y 148 (52%) con AB. Al comparar ambos grupos, no hubo diferencias significativas entre edad media, edad media al diagnóstico de AR y presencia de factor reumatoideo. Cinco de los 148 pacientes en tratamiento biológico desarrollaron psoriasis. La prevalencia de psoriasis cutánea fue 3,4% (IC 95% 1,1-7,7). La mayoría de los casos se presentaron como psoriasis gutata. La duración media del tratamiento hasta la aparición de psoriasis fue de 31,6 meses (DS 26,8). Un paciente teníaantecedentes familiares de psoriasis. Ningún paciente del grupo DMAR desarrolló psoriasis (p <0,0001). En 2 pacientes que suspendieron el AB hubo remisión completa de la manifestación cutánea y en 3 pacientes que mantuvieron el tratamiento las manifestaciones cutáneas persistieron. No se encontró asociación entre el desarrollo de psoriasis y edad al diagnóstico, tiempo de evolución de AR y tiempo de tratamiento con AB (p = NS). Concluimos que la prevalencia de psoriasis en pacientes tratados con AB (etanercept, adalimumab y abatacept) fue 3,4%. El desarrollo de psoriasis cutánea no se asoció a edad al diagnóstico, tiempo de evolución de AR ni tiempo de tratamiento con agentes biológicos.(AU)

The objectives of this study were to determine the prevalence of psoriasis in patients with rheumatoid arthritis (RA) who were treated with biological agents (BA) and analize its clinical features in apopulation of Tucumán. We included 284 patients with RA. One hundred and forty-eight patients received treated with AB and 136 patients were treated with disease modifying anti-rheumatic drugs (DMARD), and they were selected by simple random sampling. Of the 284 patients evaluated, 242 (85%) were female, mean age was 56.4 ± 13.4 years, mean age at diagnosis of RA was 42.3 ± 16.7 years with a mean time of disease progression of 11.9 ± 8.5 years. Two hundred and fourty-one patients (85%) were seropositive for rheumatoid factor. One hundred thirty-six patients (48%) were treated with DMARD and 148 (52%) received BA. When we compared both groups, there was no significant difference between mean age, age at diagnosis of RA and presence of rheumatoid factor.Five of 148 patients developed psoriasis in the BA group, after receiving the first BA. The prevalence of cutaneous psoriasis was 3.4% (95% CI 1.1-7.7). Most cases were presented as gutata psoriasis. The average duration of treatment to onset of psoriasis was31.6 months (SD 26.8). One patient had a family history of psoriasis. In the group with DMARD, neither patient developed psoriasis (p<0.0001). Remission of the cutaneous manifestation was observed in 2 patients that discontinued the BA and 3 maintained treatment with persistance of the symptoms. No association was found between the development of psoriasis and age at diagnosis, RA duration and treatment time with BA (p = NS). We conclude that the prevalence of psoriasis in patients treated with BA (etanercept, adalimumab and abatacept) was 3.4%. The development of skin psoriasis was not associated with age at diagnosis, RA duration or time of treatment with biological agents.(AU)

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Los objetivos del estudio fueron determinar la prevalencia de psoriasis en pacientes con Artritis Reumatoidea (AR) tratados con Agentes Biológicos (AB) y analizar sus características clínicas en una población de Tucumán.Se incluyeron 284 pacientes con AR. Ciento cuarenta y ocho en tratamiento con AB y 136 pacientes en tratamiento con Drogas Modificadoras de AR (DMAR), seleccionados por muestreo aleatorio simple. De los 284 pacientes evaluados, 242 (85%) fueron de sexo femenino, edad media de 56,4 años ± 13,4, la edad media al diagnóstico de AR fue de 42,3 años ± 16,7 con un tiempo de evolución de la enfermedad de 11,9 años ± 8,5. Doscientos cuarenta y un pacientes (85%) fueron seropositivos para Factor Reumatoideo (FR). Ciento treinta y seis (48%) fueron tratados con DMAR y 148 (52%) con AB. Al comparar ambos grupos, no hubo diferencias significativas entre edad media, edad media al diagnóstico de AR y presencia de factor reumatoideo. Cinco de los 148 pacientes en tratamiento biológico desarrollaron psoriasis. La prevalencia de psoriasis cutánea fue 3,4% (IC 95% 1,1-7,7). La mayoría de los casos se presentaron como psoriasis gutata. La duración media del tratamiento hasta la aparición de psoriasis fue de 31,6 meses (DS 26,8). Un paciente teníaantecedentes familiares de psoriasis. Ningún paciente del grupo DMAR desarrolló psoriasis (p <0,0001). En 2 pacientes que suspendieron el AB hubo remisión completa de la manifestación cutánea y en 3 pacientes que mantuvieron el tratamiento las manifestaciones cutáneas persistieron. No se encontró asociación entre el desarrollo de psoriasis y edad al diagnóstico, tiempo de evolución de AR y tiempo de tratamiento con AB (p = NS). Concluimos que la prevalencia de psoriasis en pacientes tratados con AB (etanercept, adalimumab y abatacept) fue 3,4%. El desarrollo de psoriasis cutánea no se asoció a edad al diagnóstico, tiempo de evolución de AR ni tiempo de tratamiento con agentes biológicos.

The objectives of this study were to determine the prevalence of psoriasis in patients with rheumatoid arthritis (RA) who were treated with biological agents (BA) and analize its clinical features in apopulation of Tucumán. We included 284 patients with RA. One hundred and forty-eight patients received treated with AB and 136 patients were treated with disease modifying anti-rheumatic drugs (DMARD), and they were selected by simple random sampling. Of the 284 patients evaluated, 242 (85%) were female, mean age was 56.4 ± 13.4 years, mean age at diagnosis of RA was 42.3 ± 16.7 years with a mean time of disease progression of 11.9 ± 8.5 years. Two hundred and fourty-one patients (85%) were seropositive for rheumatoid factor. One hundred thirty-six patients (48%) were treated with DMARD and 148 (52%) received BA. When we compared both groups, there was no significant difference between mean age, age at diagnosis of RA and presence of rheumatoid factor.Five of 148 patients developed psoriasis in the BA group, after receiving the first BA. The prevalence of cutaneous psoriasis was 3.4% (95% CI 1.1-7.7). Most cases were presented as gutata psoriasis. The average duration of treatment to onset of psoriasis was31.6 months (SD 26.8). One patient had a family history of psoriasis. In the group with DMARD, neither patient developed psoriasis (p<0.0001). Remission of the cutaneous manifestation was observed in 2 patients that discontinued the BA and 3 maintained treatment with persistance of the symptoms. No association was found between the development of psoriasis and age at diagnosis, RA duration and treatment time with BA (p = NS). We conclude that the prevalence of psoriasis in patients treated with BA (etanercept, adalimumab and abatacept) was 3.4%. The development of skin psoriasis was not associated with age at diagnosis, RA duration or time of treatment with biological agents.

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A flow system designed with solenoid micro-pumps is proposed for the determination of paraquat in natural waters. The procedure involves the reaction of paraquat with dehydroascorbic acid followed by spectrophotometric measurements. The proposed procedure minimizes the main drawbacks related to the standard chromatographic procedure and to flow analysis and manual methods with spectrophotometric detection based on the reaction with sodium dithionite, i.e. high solvent consumption and waste generation and low sampling rate for chromatography and high instability of the reagent in the spectrophotometric procedures. A home-made 10-cm optical-path flow cell was employed for improving sensitivity and detection limit. Linear response was observed for paraquat concentrations in the range 0.10-5.0 mg L(-1). The detection limit (99.7% confidence level), sampling rate and coefficient of variation (n=10) were estimated as 22 microg L(-1), 63 measurements per hour and 1.0%, respectively. Results of determination of paraquat in natural water samples were in agreement with those achieved by the chromatographic reference procedure at the 95% confidence level.

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PURPOSE: To evaluate diagnostic accuracy of FDG-PET in the definition of non-small cell lung cancer (NSCLC) and analyze diagnostic validity of CT scan and FDG-PET in its staging. METHODS: Patients with clinical suspicion of potentially resectable NSCLC (n = 108) were studied by standard procedures in our setting, including fibrobronchoscopy, transthoracic fine-needle aspiration, thoracoabdominal CT scan and FDG-PET. Gold standard was histopathological study in patients who underwent surgery and by specific imaging methods and biopsy, when available, in patients who did not. RESULTS: In 13% of patients, the FDG-PET findings were negative and no tumor was observed in the histological study of the piece. In 22% of patients, FDG-PET detected metastatic disease (M0 by CT scan). For mediastinal involvement, global diagnostic accuracy was 0.90 with FDG-PET and 0.59 with CT scan. False positive FDG-PET findings were produced by inflammatory conditions and false negative findings by the small size or proximity of lymph nodes to primary tumor. Mediastinal staging by CT scan and FDG-PET was correct in 56% and 87% of patients, respectively. CONCLUSIONS: Although complementary, the functional method (FDG-PET) is significantly superior to the structural method (CT) for detection of mediastinal tumor disease.

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OBJECTIVE: Describe our experience with 18F-fluorodeoxyglucose positron emission tomography (FDG-PET), in patients with uterine sarcomas, under suspicion of recurrence and in tumour staging after hysterectomy as an incidental pathology finding. MATERIAL AND METHODS: A retrospective review, between april 2002 and january 2006, of FDG-PET performed in 10 patients with clinical diagnosis of uterine sarcoma was made (7 patients under recurrence suspicion and three under initial staging). Mean age was 52.2 yrs. Evolution time after initial diagnosis vary from one month to 15 yrs (median time: 14 months). Lesions were classified as 8 leiomyosarcomas and 2 carcinosarcomas. FIGO staging were establish resulting 5 patients stage I, 1 patient stage III, and 4 patients stage IV. RESULTS: 4 of 7 patients under suspicion of recurrence showed discrepancies between positron emission tomography (PET) and conventional imaging techniques (CIT) information. FDG-PET was negative in three cases of non-conclusive CT. PET was negative in one case with pulmonary metastases. The 3 staging studies were concordant both FDG-PET and CIT images. Pathological information was obtained in 5 cases, and a mean time of 14 months of clinical follow up was made. CONCLUSIONS: FDG-PET can be useful in the follow up of uterine sarcoma patients, and also when it is an incidental finding in other causes hysterectomy.

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OBJECTIVE: To assess the utility of FDG-PET in the follow-up of patients treated for endometrial cancer and with suspicion of recurrence according to conventional imaging methods (CT, MRI) and/or elevation of serum tumour markers. MATERIALS AND METHODS: Between April 2002 and December 2005, eleven patients underwent 17 FDG-PET studies (six with 2 studies); mean age was 63.4 yrs (range, 52-69 yrs) and time since diagnosis ranged from 11 months to 12 yrs (mean of 56 months). Initially, seven patients were in stage I, three in stage III and one in stage IV (FIGO classification). Histologically, they corresponded to 8 endometrioid carcinomas and 3 non endometrioid carcinomas. RESULTS: FDG-PET showed infradiaphragmatic uptake in 3 patients and disseminated disease in 7 cases. FDG-PET showed no uptake in one patient. CT (n = 7) or MRI (n = 7) detected infradiaphragmatic lesions in 5 patients and visceral lesions in 2. In 11 patients, tumour markers were elevated (CA125, n = 9; CA19.9, n = 2; CA15.3, n = 2). In 7 patients, FDG-PET modified the information yielded by conventional imaging techniques and in 4 patients, the FDG-PET contributed no additional information. In 2 patients, histologic confirmation of the lesions was obtained and in 9 patients, there were clinical follow-up (from 3 to 20 months, mean of 8.7 months) and imaging studies. CONCLUSIONS: FDG-PET is superior to CT and MRI for detecting recurrences in the follow-up of patients with endometrial cancer.

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An on-line system with vapour generation (VG) and Fourier transform infrared (FTIR) spectrometric detection has been developed for the determination of free ammonium and organic nitrogen in agrochemical formulations containing hydrolyzed proteins. Commercial samples were digested, in batch mode, with sulphuric acid and the obtained solution was alkalinized on-line to transform the NH(4)(+) to NH(3) that was continuously monitored by FTIR. Free ammonium was determined in the same system after simple dilution of undigested samples with water. Different gas phase separators were assayed in order to introduce gaseous NH(3) into a home made IR gas cell of 10 cm pathlength, where the corresponding FTIR spectra were acquired by accumulating 10 scans per spectrum. The 967.0 cm(-1) band was used for the quantification of ammonia. The figures of merit of the proposed method involve a linear range up to 100 mg L(-1), a limit of detection (3sigma) of 1.4 mg L(-1) of N, a limit of quantification (10sigma) of 4.8 mg L(-1) of N, a precision (R.S.D.) of 3.0% for 10 replicate determinations of a 10.0 mg L(-1) of N and a sample measurement frequency of 60 h(-1). The method was successfully applied to the determination of free ammonium and total N in commercial amino acid formulations and results compare well with those obtained by the Kjeldhal method.

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Arsenic compounds including arsenous acid (As(III)), arsenic acid (As(V)), dimethylarsinic acid (DMA) and monomethylarsonic acid (MMA) were separated by high-performance liquid chromatography (HPLC) and detected by inductively coupled plasma mass spectrometry (ICP-MS). A Hamilton PRX-100 anionic-exchange column and a pH 8.5 K(2)HPO(4)/KH(2)PO(4) 5.0x10(-3)molL(-1) mobile phase were used to achieve arsenic speciation. The separation of arsenic species provided peaks of As(III) at 2.75min, DMA at 3.33min, MMA at 5.17min and As(V) at 12.5min. The detection limits, defined as three times the standard deviation of the lowest standard measurements, were found to be 0.2, 0.2, 0.3 and 0.5ngmL(-1) for As(III), DMA, MMA and As(V), respectively. The relative standard deviation values for a solution containing 5.0mugL(-1) of As(III), DMA, MMA and As(V) were 1.2, 2.1, 2.5 and 3.0%, respectively. This analytical procedure was applied to the speciation of arsenic compounds in drinking (soft drink, beer, juice) samples. The validation of the procedure was achieved through the analysis of arsenic compounds in water and sediment certified reference materials.

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We have reviewed the legislation about the quality control of dose calibrator. The importance of verifying the correct work of these instruments, is fundamental in daily practice of radiopharmacy and nuclear medicine. The Spanish legislation establishes to include these controls as part of the quality control of radiopharmaceuticals, and the program of quality assurance in nuclear medicine. We have reviewed guides and protocols from international eminent organizations, summarizing the recommended tests and periodicity of them.

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OBJECTIVE: This study was designed to assess the diagnostic accuracy of single photon emission computed tomography with Tl-201 (SPECT Tl-201) to establish the tumoral or non-tumoral nature of brain space occupying lesions in comparison with usual diagnostic techniques. MATERIAL AND METHODS: The study population consisted of 37 patients, 24 men (64.9 %) and 13 women (35.1 %), mean age 48 +/- 16 years. After establishing the clinical and radiological diagnosis of brain lesion, all patients underwent SPECT Tl-201, evaluating it only by subjective analysis and blinded to neuroestructural techniques. After surgical resection all patients were evaluated anatomopathologically to establish the histologic nature. RESULTS: The sensitivity of SPECT Tl-201 (0.87) was higher than standard neuroimaging techniques (0.78). Specificity (0.43), positive (0.87) and negative (0.43) predictive values of SPECT were similar to neuroestructural procedures (MRI and CT scan) with 0.43, 0.82 and 0.38 values. Tumoral disease prevalence was 0.81. Neuroestructural procedures were non-conclusive in 18.9 % of the studies. No non-conclusive results were obtained with SPECT Tl-201. CONCLUSIONS: SPECT Tl-201 is a diagnostic procedure of high sensitivity to establish the tumoral nature of brain lesions, with poor specificity, similar to structural X-ray techniques.

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Insolubles determination is one of the parameters usually recommended to evaluate the residual life of oil because their presence at elevated levels in diesel lubricating oil changes the viscosity, prematurely clogs filters and is one of the major factors in causing abrasive engine wear. The proposed method employs visible spectrophotometric detection in association with flow injection analysis. The results obtained by this method were compared with the ones obtained by Fourier transform infrared spectrometry (FT-IR) since this is the most employed method for insolubles determination. The proposed method presented a linear response from 0 to 3% (w/w) of insolubles in pentane (ASTM D-893). The sampling frequency was about 30 samplesh(-1), with a relative standard deviation (n=5) of 2.4% or better. Accuracy was evaluated analysing 98 real samples and the results obtained with the FIA-spectrophotometric method were plotted against those obtained by the FT-IR method by means of linear regression. Slope and intercept of the straight line obtained were compared with the theoretical values of 1 and 0 by means of the joint-confidence ellipse F-test. At the confidence level of 95% no evidence of a difference was found between both methods.

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An analytical methodology has been developed for the UV-spectrophotometric determination of carbaryl in waters after its preconcentration onto a polyether type polyurethane foam followed by on-line elution. The aforementioned strategy offers an easy way for in-field sampling and to improve the analytical sensitivity. Several chemical and flow variables (mass of sorbent, sample flow rate, sample volume and carrier flow rate) were studied to ensure the best performance of the system. Recovery studies, carried out on natural water samples spiked with known amounts of carbaryl at concentration levels between 250 and 500 mug l(-1), provided recovery percentages between 94 and 105%. A detection limit of 12 mug l(-1) was achieved and a variation coefficient of 3.4% was obtained at 0.50 mug ml(-1).

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A quantitative method based on FTIR has been developed to determine carbonate in synthetic apatites. The method measures the evolved CO2 after reaction of 50 mg apatite with 2 mL of hydrochloric acid (0.5 M) in a reaction vessel, heated to 40 degrees C. The CO2 evolved was swept by a carrier of nitrogen to a laboratory-made infrared gas cell of 39 mm pathlength and 490 microL volume. The signals were recorded as a function of time and the areas of the chemigram peaks obtained from the measurements in the wavenumber range of 2,500-2,150 cm(-1), were interpolated using a calibration curve. The method can be used to study apatites with carbonate contents below 0.2% with a sampling frequency of 8 h(-1).

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