Used Biomarker (used + biomarker)

Distribution by Scientific Domains

Selected Abstracts

Determinants of urinary 8-hydroxy-2,-deoxyguanosine in Chinese children with acute leukemia

You Yang
Abstract The 8-hydroxy-2,-deoxyguanosine (8-OHdG), an oxidized nucleoside of DNA, not only is a widely used biomarker for the measurement of endogenous oxidative DNA damage, but might also be a risk factor for many diseases including cancer. Elevated level of urinary 8-OHdG has been detected in patients with various malignancies. In the present study, the level of urinary 8-OHdG was examined in 116 Chinese children with acute leukemia (94 acute lymphoid leukemia, ALL, 22 acute myeloid leukemia, AML), and its correlation with urinary metal elements was investigated. Our result showed that the level of urinary 8-OHdG in children with acute leukemia before treatment was significantly elevated compared with that in normal controls (11.92 ± 15.42 vs. 4.03 ± 4.70 ng/mg creatinine, P < 0.05). In particular, urinary 8-OHdG was higher in children with acute leukemia aged under 3 years (20.86 ± 21.75 ng/mg creatinine) than in those aged 3,15 years (8.09 ± 9.65 ng/mg creatinine), whereas no differences were shown in terms of gender, parental smoking and education, household income, place of residence, and use of paracetamol. In addition, urinary 8-OHdG levels were similar among different subtypes of acute lymphoid leukemia (ALL) patients. Furthermore, linear regression analysis revealed a significant correlation between urinary 8-OHdG and urinary Cr, but not Fe or As, in group aged <3 years compared with group aged 3,15 years (P = 0.041), indicating that the metal elements may be involved in increasing urinary 8-OHdG level in younger children with acute leukemia. Our results suggest that children with acute leukemia undergo an increased risk of oxidative DNA damage, which may be correlated with high level of Cr exposure in Chinese children with acute leukemia. © 2008 Wiley Periodicals, Inc. Environ Toxicol, 2009. [source]

Senescence-associated ,-galactosidase is lysosomal ,-galactosidase

AGING CELL, Issue 2 2006
Bo Yun Lee
Summary Replicative senescence limits the proliferation of somatic cells passaged in culture and may reflect cellular aging in vivo. The most widely used biomarker for senescent and aging cells is senescence-associated ,-galactosidase (SA-,-gal), which is defined as ,-galactosidase activity detectable at pH 6.0 in senescent cells, but the origin of SA-,-gal and its cellular roles in senescence are not known. We demonstrate here that SA-,-gal activity is expressed from GLB1, the gene encoding lysosomal ,-D-galactosidase, the activity of which is typically measured at acidic pH 4.5. Fibroblasts from patients with autosomal recessive GM1 -gangliosidosis, which have defective lysosomal ,-galactosidase, did not express SA-,-gal at late passages even though they underwent replicative senescence. In addition, late passage normal fibroblasts expressing small-hairpin interfering RNA that depleted GLB1 mRNA underwent senescence but failed to express SA-,-gal. GLB1 mRNA depletion also prevented expression of SA-,-gal activity in HeLa cervical carcinoma cells induced to enter a senescent state by repression of their endogenous human papillomavirus E7 oncogene. SA-,-gal induction during senescence was due at least in part to increased expression of the lysosomal ,-galactosidase protein. These results also indicate that SA-,-gal is not required for senescence. [source]

Cholinesterase and glutathione- S -transferase activities in freshwater invertebrates as biomarkers to assess pesticide contamination

Inęs Domingues
Abstract Studies investigating the use of biomarkers in pesticide risk assessment have greatly increased in recent years; however, issues concerning the ecological meaning of enzymatic responses have proved controversial. Ideally a good biomarker response should be modulated by the environmental contaminants alone and demonstrate a predictable behavior towards certain types of toxins. As these premises are rarely observed, the present study aims to outline research that has contributed to an understanding of the behavior of two widely used biomarkers, cholinesterase and glutathione- S -transferase, describing environmental and biotic factors that affect their response in freshwater invertebrates. Studies were performed in the main classes of aquatic invertebrates with these biomarkers and conclusions were reached concerning their behavior towards the main classes of pesticides. Links between biomarker responses and conventional endpoints were evaluated so that ecological relevance could be attributed to enzymatic responses. Toxicity of mixtures was investigated, and cases of synergism and antagonism were pointed out as factors changing the expected toxicity of aquatic systems and leading to misinterpretations of biomarker responses. Finally, the use of biomarkers as a tool for biomonitoring and in situ assays was investigated, with discussion of advantages and disadvantages of their use. Environ. Toxicol. Chem. 2010;29:5,18. © 2009 SETAC [source]

Biomarkers of aging in Drosophila

AGING CELL, Issue 4 2010
Jake Jacobson
Summary Low environmental temperature and dietary restriction (DR) extend lifespan in diverse organisms. In the fruit fly Drosophila, switching flies between temperatures alters the rate at which mortality subsequently increases with age but does not reverse mortality rate. In contrast, DR acts acutely to lower mortality risk; flies switched between control feeding and DR show a rapid reversal of mortality rate. Dietary restriction thus does not slow accumulation of aging-related damage. Molecular species that track the effects of temperatures on mortality but are unaltered with switches in diet are therefore potential biomarkers of aging-related damage. However, molecular species that switch upon instigation or withdrawal of DR are thus potential biomarkers of mechanisms underlying risk of mortality, but not of aging-related damage. Using this approach, we assessed several commonly used biomarkers of aging-related damage. Accumulation of fluorescent advanced glycation end products (AGEs) correlated strongly with mortality rate of flies at different temperatures but was independent of diet. Hence, fluorescent AGEs are biomarkers of aging-related damage in flies. In contrast, five oxidized and glycated protein adducts accumulated with age, but were reversible with both temperature and diet, and are therefore not markers either of acute risk of dying or of aging-related damage. Our approach provides a powerful method for identification of biomarkers of aging. [source]