Accelerated solvent extraction method for the quantification of polycyclic aromatic hydrocarbons in cocoa beans by gas chromatography-mass spectrometry

An accelerated solvent extraction (ASE) procedure for use with gas chromatography-mass spectrometry (GC-MS) was optimized for the determination of eight polycyclic aromatic hydrocarbons (PAHs) in cocoa beans. Plackett-Burman and rotatable central composite design (RCCD) indicated that three variables affected the recoveries of PAHs during the extraction and purification steps: agitation time in the second liquid-liquid partition, weight of silica gel in the column, and volume of hexane for PAH elution from the column. After obtaining the optimal conditions, a single laboratory method validation was performed. Linearity was demonstrated for benzo[a]pyrene in the concentration range from 0.5 to 8.0mgkg^-1 of sample, corresponding to 1.25-20.0μgkg^-1 of cocoa on a fat basis. For the other analytes, linearity was observed from 0.75 to 8.0μgkg^-1 of sample (1.88-20.0μgkg^-1 of cocoa on a fat basis). Significant matrix effects were found for chrysene and benzo[b]fluoranthene. The precision of the method was verified with relative standard deviations (RSDs) ranging from 2.57 to 14.13% and from 4.36 to 19.77% under repeatability and intermediate precision conditions, respectively. The average recoveries of the eight PAHs ranged from 74.99 to 109.73%. These parameters, limits and measurement uncertainties met the performance criteria established by European Union regulations, except for the theoretical limit of detection for chrysene. The method was applied to the analysis of samples of Brazilian cocoa beans, and only one sample was found to have a PAH content above the maximum limit defined by the European Union legislation. This optimized and validated method is intended to be used as part of the official Brazilian monitoring programs investigating contaminants and residues in food.

An appropriate and systematized procedure for validating qualitative methods: its application in the detection of sulfonamide residues in raw milk

The lack of well-established references for the validation of qualitative analyses and the increasing demand for reliable binary responses were the main motivating factors for this study. A detailed procedure for single-laboratory validation of qualitative methods is proposed. The experimental design and the tools for data analysis were based on the theoretical background, as well as the aspects of efficiency, convenience and simplicity. Four experimental steps were defined, as follows: (i) preliminary tests for the determination of the concentration range, (ii) a study of the rates, unreliability region, detection limit, and the accordance and concordance values, (iii) a study of the selectivity in the presence of known interferences, and (iv) a study of robustness. The applicability of the procedure was demonstrated by the validation of a qualitative commercial kit for detecting sulfonamide residues in raw milk using both the visual and instrumental reading techniques. Reliability rates of 100% were obtained for the blank samples. For the samples spiked with sulfamethazine at 10.8 and 108 μg L(-1) and with sulfadimethoxine or sulfathiazole at 10 and 100 μg L(-1), the reliability rates ranged from 93.3 to 100%. Selectivity was demonstrated using trimethoprim as a potential interferent. The method was considered robust for the factors of the temperature (54 and 58°C) and time (6 and 10 min) for incubating the test strips. The estimated detection limits and unreliability regions confirmed the suitability of the kit for this purpose, based on the legislated residue limits.

Correlation between lower urinary tract symptoms and erectile dysfunction in men presenting for prostate cancer screening

Lower urinary tract symptoms (LUTS) and erectile dysfunction (ED) are age-related conditions that may have a profound impact on the quality of life. The relationship between LUTS and ED is not completely understood. In this study, we assessed this relationship in men over 45 years of age during a prostate cancer screening program. LUTS and ED were evaluated in 1267 men aged 45-75 years (mean 58.2+/-8.2 years). Patients completed the International Prostate Symptom Score (IPSS) and the International Index of Erectile Function-5 (IIEF-5). The association between LUTS and ED was analyzed and the influence of age in the results was tested. We also evaluated the influence of the intensity of LUTS in the ED severity. A total of 514 (40.6%) patients were considered symptomatic of LUTS (24.8% with mild, 11.8% with moderate and 4% with severe LUTS). ED was present in 758 (59.9%) men and was considered mild in 25.0%, moderate in 18.3% and severe in 16.7%. The IIEF-5 score had a negative correlation with both the IPSS score (r=-0.33, P<0.001) and age (r=-0.31 and P<0.001). Age was positively associated with the IPSS score (r=0.14 and P<0.001). A significant correlation was observed between LUTS and ED, with 57.6% of the men with LUTS presenting ED as opposed to 29.7% of the asymptomatic population (odds ratio=3.32; 95% CI =2.57-4.29, P<0.001). Age-adjusted univariate analysis revealed a significant and independent influence of LUTS on the incidence of ED (odds ratio=2.72; 95% CI=2.08-3.57, P<0.001). IIEF scores varied significantly according to the severity of the urinary symptoms. Our findings in a prostate cancer screening population confirm that LUTS is an age-independent predictor of ED. Furthermore, they demonstrate that not only the presence of LUTS increases the likelihood of developing ED, but the severity of LUTS is associated with the intensity of ED.

Dissolution test for lamivudine tablets: optimization and statistical analysis

A comparison of different methods for dissolution test used by five different manufacturer laboratories of lamivudine tablets is made, evaluated, and discussed. Dissolution medium (water and hydrochloric acid pH 1.2), apparatus (paddles and baskets) and time (30 and 60 min) were analyzed. The determination was accomplished by spectrophotometry at 270 nm. Analysis of variance (ANOVA) factorial design 5 x 2 x 2 x 2 with six repetitions, with post hoc multiple comparisons between means conducted by Duncan test at 0.05 significance level was used. After the comparative analysis of the results, optimal dissolution conditions were determined as follows: water as dissolution medium, paddles at the stirring speed of 50 rpm as apparatus and time of 30 min. The method was applied to the dissolution test of samples from eleven batches of tablets, produced by five different laboratories.

Adequação nutricional do almoço self-service de uma empresa de Santa Luzia, MG

OBJETIVO: Avaliar a adequação nutricional dos cardápios do almoço self-service de uma empresa, tomando-se como base o consumo médio diário per capita. MÉTODOS: Empregou-se o método da pesagem direta dos ingredientes, preparações, bebidas e sobras, antes e após a distribuição das refeições. RESULTADOS: O valor energético médio, corrigido pelo índice-de-rejeito (6,6%), foi de 1108kcal. Os teores de carboidratos, proteínas e lipídios forneceram, respectivamente, 51,0%, 19,0% e 30,0% de energia metabolizável. Com base nas recomendações para a população brasileira do sexo masculino (2.785kcal), os cardápios avaliados contribuíram com 40,0% da necessidade energética total, 30,0% dos carboidratos, 96,0% das proteínas e 47,0% dos lipídios. Para a população do sexo feminino (2.056kcal), os valores correspondentes foram, respectivamente, 54,0%, 41,0%, 130,0% e 64,0%. O consumo de fibra alimentar mostrou-se inadequado e correspondeu a 48,0% das necessidades diárias da clientela. CONCLUSÃO: Os usuários desta empresa necessitam receber orientações nutricionais sobre alimentação adequada, pois o almoço consumido foi hipoglicídico, hiperprotéico e hiperlipídico. Enquanto foi normocalórico para os homens, mostrou-se hipercalórico para as mulheres.

Avaliação do ácido trans, trans-mucônico urinário como biomarcador de exposição ao benzeno

OBJETIVO: Avaliar o uso do ácido trans, trans-mucônico urinário como biomarcador na monitorização da exposição ocupacional ao benzeno. MÉTODOS: Foi estudado o comportamento do ácido trans, trans-mucônico em amostras de urina de indivíduos expostos (N=36) e não expostos (N=116) ocupacionalmente ao solvente. A concentração urinária do ácido foi determinada por Cromatografia Líquida de Alta Eficiência. A amostra foi constituída de indivíduos expostos ao benzeno em uma refinaria de petróleo localizada em Belo Horizonte, MG. Foram empregados os testes estatísticos não-paramétricos de Kruskall-Wallis, Mann Witney e de correlação de Spearman, ao nível de significância de 0,05%. RESULTADOS: A exposição média ao benzeno dos trabalhadores selecionados foi de 0,15±0,05 mg/m³ (0,05 ppm) o que resultou em um valor médio do metabólito urinário de 0,19±0,04 mg/g de creatinina. A faixa de referência do ácido trans, trans-mucônico no grupo não exposto variou de 0,03 a 0,26 mg/g de creatinina (média de 0,10±0,08 mg/g de creatinina). Foi encontrada uma diferença significativa entre os níveis de ácido trans, trans-mucônico do grupo exposto e não exposto. Entretanto, não houve correlação entre os níveis do metabólito urinário e do benzeno no ar. Foi observada a correlação entre ácido trans, trans-mucônico e hábito de fumar no grupo de indivíduos expostos. A ingestão de álcool num período de até 48 horas antes da coleta das amostras não mostrou interferir nos níveis do metabólito nos dois grupos estudados. Foi observada a correlação entre ácido trans, trans-mucônico e idade (faixa etária de 18 a 25 anos) no grupo de não expostos. CONCLUSÕES: Os resultados obtidos evidenciaram a importância de ser mais bem avaliada a influência do hábito de fumar e da faixa etária do trabalhador nos níveis urinários do ácido trans, trans-mucônico.

Leishmania major-like antigen for specific and sensitive serodiagnosis of human and canine visceral leishmaniasis

An antigen (LMS) prepared from Leishmania major-like promastigotes was used in an enzyme-linked immunosorbent assay (ELISA) for the diagnosis of human and dog visceral leishmaniasis. The results were compared with those from the indirect immunofluorescent antibody test (IFAT). A total of 1822 canine sera were tested, including sera from dogs with visceral leishmaniasis, transmissible venereal tumors, ehrlichiosis, rickettsiosis, or Chagas' disease and sera from healthy dogs. The antigen was also tested with 227 samples of human sera, including sera from patients with visceral, cutaneous, or diffuse cutaneous leishmaniasis and from noninfected individuals, as well as sera from patients with Chagas' disease, toxoplasmosis, rickettsiosis, hepatitis B, schistosomiasis, ascaridiasis, malaria, rheumatoid factor, leprosy and rheumatoid factor, tuberculosis, or leprosy. All dogs and all human patients had a clinical and/or serological and/or parasitological diagnosis. For detecting antibodies in sera from dogs with leishmaniasis, the antigen showed a sensitivity of 98%, specificity of 95%, and concordance of 93% and when used for detecting antibodies in human sera presented a sensitivity of 92%, specificity of 100%, and concordance of 92%. Comparison between ELISA and IFAT demonstrated that ELISA using the LMS antigen yielded more reliable results than IFAT. The LMS antigen displayed no cross-reactivity with sera from patients or dogs that had any of the other diseases tested.