84 research outputs found
Long-term cultivation of colorectal carcinoma cells with anti-cancer drugs induces drug resistance and telomere elongation: an in vitro study
BACKGROUND: The role of telomerase activation in the expression and/or maintenance of drug resistance is not clearly understood. Therefore, we investigated the relationships, among the telomerase activity, telomere length and the expression of multidrug resistance genes in colorectal cancer cell lines cultivated with anti-cancer drugs. METHODS: LoVo and DLD-1 cells were continuously grown in the presence of both CDDP and 5-FU for up to 100 days. Cell proliferation, telomerase activity, telomere length and the expression of multidrug resistance genes were serially monitored as the PDL increased. RESULTS: The expression of multidrug resistance genes tended to increase as the PDL increased. However, an abnormal aneuploid clone was not detected as far as the cells were monitored by a DNA histogram analysis. Tumor cells showing resistance to anti-cancer drugs revealed a higher cell proliferation rate. The telomere length gradually increased with a progressive PDL. The telomerase activity reached a maximum level at 15 PDL in LoVo cells and at 27 PDL in DLD-1 cells. An increase in the mRNA expression of the telomerase components, especially in hTERT and in hTR, was observed at the same PDLs. CONCLUSIONS: These results suggest that a high telomerase activity and an elongation of telomeres both appear to help maintain and/or increase drug resistance in colorectal cancer cells. Cancer cells with long telomeres and a high proliferative activity may thus be able to better survive exposure to anti-cancer drugs. This is presumably due to an increased chromosome stability and a strong expression of both mdr-1 and MRP genes
Inorganic Mass Spectrometry
To establish a method for sensitive, accurate, and precise determination of Se in real samples, isotope dilution analysis using high-power nitrogen microwave-induced plasma mass spectrometry (N 2 MIP-IDMS) was conducted. In this study, freeze-dried human blood serum (Standard Reference Material, NIES No. 4) provided by NIES (National Institute for Environmental Studies) was used as a real sample. The measured isotopes of Se were 78 Se and 80 Se which are the major isotopes of Se. The appropriate amount of a Se spike solution was theoretically calculated by using an error multiplication factor (F) and was confirmed experimentally for the isotope dilution analysis. The mass discrimination effect was corrected for by using a standard Se solution for the measurement of Se isotope ratios in the spiked sample. However, the sensitivity for the detection of Se was not so good and the precision of the determination was not improved (2-3%) by N 2 MIP-IDMS with use of the conventional nebulizer. Therefore, a hydride generation system was connected to N 2 MIP-IDMS as a sample introduction system (HG-N 2 MIP-IDMS) in order to establish a more sensitive detection and a more precise determination of Se. A detection limit (3σ) of 10 pg mL -1 could be achieved, and the RSD was less than 1% at the concentration level of 5.0-10.0 ng mL -1 by HG-N 2 MIP-IDMS. The analytical results were found to be in a good agreement with those obtained by the standard addition method using conventional Ar ICPMS. It is well-known that Se is an essential element for all mammals. Se deficiency leads to deficiency syndromes, for example, Keshan disease, which is known for cardiac insufficiency that occurred in children and pregnant women in China. Problems also occur if the concentration of Se is too high; for example, gastroenteric disorders, dermatitis, and neurotic disorders are caused by excessive intake of Se. Moreover, it is well-known that the range of permissive intake amounts of Se is very narrow for human beings. Therefore, it is restricted as a toxic element in environmental standards. There are several sources of environmental Se pollution: the processes of Se refinement and the production processes of Se-containing products. For these reasons, the accurate and precise determination of trace levels of Se in environmental and biological samples is required, and studies of Se determination have been reported by several groups. [1][2][3][4][5][6][7][8][9][10][11] Because Ar ICPMS can measure multiple elements at a concentration range from ng mL -1 to fg mL -1 , it has widespread use in the determination of trace elements in various samples. 12-25 However
Spatial localization of bacteria controls coagulation of human blood by 'quorum acting'
The Interplay Between Thyroid Dysfunction and Kidney Disease
Hypothyroidism is a highly prevalent endocrine complication in chronic kidney disease (CKD) patients. A large body of evidence has shown that there is a bidirectional relationship between thyroid dysfunction and kidney disease, yet there are many remaining gaps in knowledge in regards to the clinical management of CKD patients with hypothyroidism, including those receiving hemodialysis and peritoneal dialysis. Given that hypothyroidism has been associated with many deleterious outcomes including a higher risk of (1) mortality, (2) cardiovascular disease, (3) impaired health-related quality of life, and (4) altered body composition in both non-CKD and CKD patients, future research is needed to establish the appropriate screening, diagnosis, and treatment approaches in these populations
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Going Nuts to Protect Kidneys and to Live Longer with Kidney Disease
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Protein intake and renal function in older patients.
Purpose of reviewChronic kidney disease (CKD) is highly prevalent in elderly patients. There is growing recognition of the importance of attention to dietary protein intake (DPI) in this population given their predisposition to age-related changes in kidney function and coexisting comorbidities (i.e., hypertension). We reviewed the impact of DPI on kidney health and survival and the role of dietary protein management in older CKD patients.Recent findingsWhile kidney function parameters including glomerular filtration rate (GFR) and renal plasma flow are slightly lower in elderly patients irrespective of CKD status, the kidneys' ability to compensate for increased DPI by augmentation of GFR is preserved until 80 years of age or less. However, long-term consumption of high DPI in individuals of older age and/or with CKD may contribute to kidney function deterioration over time. Prescription of a plant-dominant low-protein diet of 0.6-0.8 g/kg/day with more than 50% from plant sources or very low protein diets less than 0.45 g/kg/day supplemented with essential amino acids or their keto-analogues may be effective in preserving kidney function in older patients and their younger counterparts, while also monitoring for development of protein-energy wasting (PEW).SummaryUsing tailored precision nutrition approaches in prescribing plant-dominant low DPI that also maintains adequate energy and nitrogen balance may ameliorate kidney function decline while also preventing development of PEW in elderly patients with CKD
Differential Determination of Antimony(III) and Antimony(V) by Inductively Coupled Plasma Atomic Emission Spectrometry with Hydride Generation.
Differential Determination of Antimony(III) and Antimony(V) in River Water by Hydride-Generation Inductively Coupled Plasma Mass Spectrometry.
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