RESUMO
Environments prone to naturally non-biodegradable metal pollution have remained hot areas of research. Here, concentrations of Cu, Cr, Cd and Pb in 90 bovine tissue (kidney, liver and muscle) samples collected from Gondar City abattoir and Nara-Awudarda in Central Gondar Zone, Ethiopia, were investigated. The samples were dry-ashed at 550 °C for 3.45 h, mineralized with 2 mL conc. HNO3, and analysed using flame atomic absorption spectrometer. Pattern recognition methods, viz. principal component analysis (PCA) and partial least squares - discriminant analysis (PLS-DA), were employed to investigate heavy metal profiles in bovine tissues and classify them based on their geographic source. Results showed that the mean concentrations of the metals (mg/kg) extended in the range: 1.5-11.5 (Cu), 0.42-1.5 (Pb), BDL-1.05 (Cr) and BDL-0.41 (Cd). The concentrations of Cu and Cd, except Cd in muscle samples from Gondar City abattoir, were below the permissible limits while Pb and Cr, except for Pb in kidney and Cr in all samples at Gondar City abattoir, were above the permissible limits. Hence, it calls for enforceable food safety monitoring practices. PCA visualizes grouping of the studied bovine tissues based on the contents of analyzed metals where liver contained highest concentrations of the studied metals, except for Cd, which was highest in kidney. PLS-DA model clearly classified the tissue samples into two clusters depending on their geographic source. In general, the accumulation burden of heavy metals exhibited tissue-specific and sample source differences, probably due to varied organ functions and environmental conditions.
RESUMO
BACKGROUND: Nitric oxide (NO) is essential for host defense in rodents, but the role of NO during tuberculosis (TB) in man remains controversial. However, earlier observations that arginine supplementation facilitates anti-TB treatment, supports the hypothesis that NO is important in the host defense against TB. Local production of NO measured in fractional exhaled air (FeNO) in TB patients with and without HIV co-infection has not been reported previously. Thus, our aim was to investigate levels of FeNO in relation to clinical symptoms and urinary NO metabolites (uNO). METHODS: In a cross sectional study, FeNO and uNO were measured and clinical symptoms, chest x-ray, together with serum levels of arginine, tumor necrosis factor alpha (TNF-alpha) and interleukin 12 (IL-12) were evaluated in sputum smear positive TB patients (HIV+/TB, n = 36, HIV-/TB, n = 59), their household contacts (n = 17) and blood donors (n = 46) from Gondar University Hospital, Ethiopia. RESULTS: The proportion of HIV-/TB patients with an increased FeNO level (> 25 ppb) was significantly higher as compared to HIV+/TB patients, but HIV+/TB patients had significantly higher uNO than HIV-/TB patients. HIV+ and HIV-/TB patients both had lower levels of FeNO compared to blood donors and household contacts. The highest levels of both uNO and FeNO were found in household contacts. Less advanced findings on chest x-ray, as well as higher sedimentation rate were observed in HIV+/TB patients as compared to HIV-/TB patients. However, no significant correlation was found between FeNO and uNO, chest x-ray grading, clinical symptoms, TNF-alpha, IL-12, arginine levels or sedimentation rate. CONCLUSION: In both HIV negative and HIV co infected TB patients, low levels of exhaled NO compared to blood donors and household were observed. Future studies are needed to confirm whether low levels of exhaled NO could be a risk factor in acquiring TB and the relative importance of NO in human TB.