Assessment of essential and toxic elemental concentrations in tumor and non-tumor tissues with risk of colorectal carcinoma in Pakistan.

BACKGROUND: Colorectal tumor is a major cause of cancer morbidity and mortality both in USA and around the globe. Exposure to environmental toxicants such as toxic trace elements has been implicated in colorectal malignancy. However, data linking them to this cancer are generally lacking. METHODS: Accordingly, the current study was to investigate the distribution, correlation and chemometric evaluation of 20 elements (Ca, Na, Mg, K, Zn, Fe, Ag, Co, Pb, Sn, Ni, Cr, Sr, Mn, Li, Se, Cd, Cu, Hg and As) in the tumor tissues (n = 147) and adjacent non tumor tissues (n = 147) of same colorectal patients which were analyzed by flame atomic absorption spectrophometry employing nitric acid-perchloric acid based wet digestion method. RESULTS: On the average, Zn (p < 0.05), Ag (p < 0.001), Pb (p < 0.001), Ni (p < 0.01), Cr (p < 0.005) and Cd (p < 0.001) showed significantly higher levels in the tumor tissues compared with the non tumor tissues of patients, whereas mean levels of Ca (p < 0.01), Na (p < 0.05), Mg (p < 0.001), Fe (p < 0.001), Sn (p < 0.05) and Se (p < 0.01), were significantly elevated in the non tumor tissues than the tissues of tumor patients. Most of the elements revealed markedly disparities in their elemental levels based on food (vegetarian/nonvegetarian) habits and smoking (smoker/nonsmoker) habits of donor groups. The correlation study and multivariate statistical analyses demonstrated some significantly divergent associations and apportionment of the elements in the tumor tissues and non tumor tissues of donors. Noticeably, variations in the elemental levels were also noted for colorectal tumor types (lymphoma, carcinoids tumor and adenocarcinoma) and stages (I, II, III, & IV) in patients. CONCLUSION: Overall, the study revealed that disproportions in essential and toxic elemental concentrations in the tissues are involved in pathogenesis of the malignancy. These findings provide the data base that helps to oncologist for diagnosis and prognosis of colorectal malignant patients.

Lead (Pb) distribution and accumulation in different plant parts and its associations with grain Pb contents in fragrant rice.

Lead (Pb) affects the growth and productivity of rice negatively through soil-Pb-plant interactions. A pot experiment was conducted to assess the Pb uptake and its distributive pattern in different fragrant rice cultivars i.e., Meixiangzhan-2 (MXZ-2), Xiangyaxiangzhan (XYXZ), Guixiangzhan (GXZ), Basmati-385 (B-385), and Nongxiang-18 (NX-18) and relationship of Pb uptake with grain Pb-contents and rice yield and related traits i.e., productive tillers hill-1, spikelets panicle-1, filled grain percentage, and 1000-grain weight. Lead as Pb(NO3)2 was applied at 0 (control), 400 (Pb1), 800 (Pb2) and 1200 mg kg-1 (Pb3) of soil in solution form. Results showed that all rice cultivars accumulated different concentration of Pb, with the highest in roots and the lowest in grains. The translocation factors (TF) from stems to leaves were higher than root to stems and leaves to ears/grains. The grain Pb contents have significant positive associations with ear Pb contents and TF of Pb from leaves to ear at reproductive stage. Moreover, relative changes (RC) in grain yields have significant correlations with the RC in some yield attributes i.e., productive tillers per hill, spikelets per panicle, and filled grain percentage under Pb toxicity. Overall, grain Pb contents are affected mainly by the transference of leaves Pb contents to ears/grains (an index to determine final grain Pb contents) whereas RC in rice yields suggested its relationships with some agronomic attributes of fragrant rice under Pb stress.