Biomarkers blood

Because control of renal function and blood pressure is multifactorial, the causal contribution of lead is difficult to isolate. A number of biomarkers (blood, tibial, and patella lead), and a variety of populafions differing by age, gender, race, and level of exposure are examined. Systohc and diastolic pressures are assessed separately and may be analyzed both as continuous or dichotomous variables. Kidney function is assessed by the serum creatinine concentration or empirical adjustments of the creatinine to estimate GFR. Large populations are required to achieve statistical significance amidst the noise of the multifactorial causality and the imprecision of outcome measures. Inconsistent results and weak correlations are, therefore, expected as smaller and smaller outcome effects are evaluated. 

Hanash, S.M., Balk, C.S., Kallioniemi, O. Emerging molecular biomarkers—blood-based strategies to detect and monitor cancer. Nat. Rev. Clin. Oncol. 8, 142-150 (2011)... 

The O Flaherty PB-PK model was constructed to simulate levels of Pb in the Pb exposure biomarkers blood and bone for all ages in Pb-exposed human populations from birth through adulthood. The model in its operational features was described in various articles and systematic reviews (O Haherty, 1993, 1995, 1998, 2000). Figure 9.4 depicts the operational structure of the model, which includes intakes, multitissue distributions, and routes of elimination. 

Nilsson, R.J.A., Balaj, L., HuUeman, E., Van Rijn, S., Pegtel, D.M., Walraven, M., 2015. Brief report blood platelets contain tumor-derived RNA biomarkers. Blood 118, 1—3. 

Methyl parathion has been detected in blood within 1 day of exposure and is a specific biomarker (Fazekas 1971). 

Nigg HN, Knaak JB. 2000. Blood cholinesterases as human biomarkers of organophosphorus pesticide exposure. Rev Environ Contam Toxicol 163 29-112. 

Agarwal et al. 1978), the quantification of these specific enzymes may indicate that exposure to endosulfan has occurred. Blood tests, such as decay curves for aminopyrine in plasma, which are semiquantitative indices of liver enzyme induction, have been used successfully in the past to demonstrate enzyme induction in pesticide-exposed workers. Because numerous chemicals found at hazardous waste sites also induce these hepatic enzymes, these measurements are not specific for endosulfan exposure. However, measurements of enzyme activity, together with the detection of the parent compound or its metabolites in tissue or excreta, can be useful indicators of exposure. All of these potential biomarkers require further verification in epidemiological studies. Further studies with focus on the development of methods to separate and measure the estrogenicity of endosulfan in in vitro assays would be valuable since these assays are more sensitive and discriminative than other conventional biomarkers. Preliminary results have been presented by Sonnenschein et al. (1995). 

Methods for Determining Biomarkers of Exposure and Effect. GC/ECD, GC/MS, and GC/MC are analytical techniques used for measuring endosulfan in blood, urine, hand rinses, and various biological tissues and excreta at low- and sub-ppb levels (Coutselinis et al. 1976 Demeter and Heyndrickx 1978 Demeter et al. 1977 Griffith and Blanke 1974 Guardino et al. 1996 Kazen et al. 

At the practical level, an ideal mechanistic biomarker should be simple to use, sensitive, relatively specific, stable, and usable on material that can be obtained by nondestructive sampling (e.g., blood or skin). A tall order, no doubt, and no biomarker yet developed has all of these attributes. However, the judicious use of combinations of biomarkers can overcome the shortcomings of individual assays. The main point to emphasize is that the resources so far invested in the development of biomarker technology for environmental risk assessment has been very small (cf the investment in biomarkers for use in medicine). Knowledge of toxic mechanisms of organic pollutants is already substantial (especially of pesticides), and it grows apace. The scientific basis is already there for technological advance it all comes down to a question of investment. 

With investigations of phytochemicals and functional foods, the outcome measure is generally going to be a biomarker of disease, such as serum cholesterol level as a marker of heart disease risk, or indicators of bone turnover as markers of osteoporosis risk. Alternatively, markers of exposure may also indicate the benefit from a functional food by demonstrating bioavailability, such as increased serum levels of vitamins or carotenoids. Some components will be measurable in both ways. For instance, effects of a folic acid-fortified food could be measured via decrease in plasma homocysteine levels, or increase in red blood cell folate. 

L (1999) Effect of parsley intake on urinary apigenin excretion, blood antioxidant enzymes and on biomarkers for oxidative stress in hiunans, Brit J Nutr, 81, 447-55. 

Experimental evidence in humans is based upon intervention studies with diets enriched in carotenoids or carotenoid-contaiifing foods. Oxidative stress biomarkers are measured in plasma or urine. The inhibition of low density lipoprotein (LDL) oxidation has been posmlated as one mechanism by which antioxidants may prevent the development of atherosclerosis. Since carotenoids are transported mainly via LDL in blood, testing the susceptibility of carotenoid-loaded LDL to oxidation is a common method of evaluating the antioxidant activities of carotenoids in vivo. This type of smdy is more precisely of the ex vivo type because LDLs are extracted from plasma in order to be tested in vitro for oxidative sensitivity after the subjects are given a special diet. 

Nielsen JB, Andersen O, Grandjean P. 1994. Evaluation of mercury in hair, blood and muscle as biomarkers for methylmercury exposure in male and female mice. Arch Toxicol 68 317-321. 

Exposure. Americium may be detected in samples of urine, blood, feces, or body tissues. Due to the relatively long biological half-time of americium, short-term exposures cannot be readily distinguished from longer-term ones. No new biomarkers of exposure are needed at this time. 

Growing clinical data also points to the importance of IL-8 in atherogenesis. IL-8 has been found in atheromatous lesions from patients with atherosclerotic disease including carotid artery stenosis (103), CAD (118), abdominal aortic aneurysms (AAA) (103,104,114), and peripheral vascular disease (PVD) (104). Furthermore, studies using plaque explant samples have yielded more direct evidence for IL-8 involvement. Media from cultured AAA tissue induced IL-8-dependent human aortic endothelial cell (HAEC) chemotaxis (122). Homocysteine, implicated as a possible biomarker for CAD, is also capable of inducing IL-8 (123-125) by direct stimulation of endothelial cells (123,124) and monocytes (125). When patients with hyperhomocysteinemia were treated with low-dose folic acid, decreases in homocysteine levels correlated with decreases in IL-8 levels (126). Statins significantly decrease serum levels of IL-6, IL-8, and MCP-1, as well as expression of IL-6, IL-8, and MCP-1 mRNA by peripheral blood monocytes and HUVECs (127). Thus, IL-8 may be an underappreciated factor in the pathogenesis of atherosclerosis. 

Thus, IMPA in the urine may be an accurate biomarker of recent diisopropyl methylphosphonate exposure. IMPA can be detected in the blood as well as in the urine. However, since IMPA is cleared from the blood rapidly, its detection may only be useful for monitoring recent exposure. 

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