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Results for “Biomarker testing”

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At least 919 records · Page 51Linked to original sources
PubMed2001

[Pancreatic phospholipase A2].

Pancreatic phospholipase A2 is one of the digestive enzymes in pancreatic juice. As there are other phospholipase activities in the serum, serum pancreatic phospholipase A2 is measured by immunoassay. A decrease in the serum level of this enzyme is significantly correlated with pancreatic dysfunction demonstrated by the secretin test. Recently, pancreatic phospholipase A2 was reported to be a potent growth factor, and its receptor on the cell surface was cloned.

Biomarkers↗
PubMed2002

Biomarkers in toxicology versus ecological risk assessment.

Toxicity testing of drugs, pesticides, and hazardous compounds has evolved into a battery of standardized tests conducted in a range of surrogate test organisms. The toxicity of these xenobiotics in terms of their LD(50) and LC(50) (Dose or concentration lethal to 50% of the test population), ED(50) and EC(50) (Dose or concentration producing a specified response in 50% of the test population), MATC (Maximum acceptable toxicant concentration), LOEL (Lowest observable effects level), LOEC (Lowest observable effects concentration), NOEL (No observable effects level) or NOEC (No observable effects concentration) is extrapolated to humans and wildlife. Historical failures in the risk assessment process have been largely due to over reliance on regulatory toxicology and an 'assembly line' mentality to toxicology. The importance of toxicokinetics, receptor studies and biomarkers are reviewed, firstly, with reference to toxicological incidences in drug development programmes, and secondly, with reference to improved environmental risk assessment of pesticides and other contaminants. Ecological risk assessments also require multidisciplinary skills to study the entry, distribution, and biological effect and fate of chemicals to fully characterise and understand the potential adverse implications of contamination. Optimum integration of chemical measurements and biomarker responses is a challenge that will lead to an improved understanding of adverse effects and their significance in both human and ecological risk assessment.

Animals↗
PubMed2005

Blood-based biomarkers for detecting mild osteoarthritis in the human knee.

OBJECTIVE: This study was designed to test the utility of a blood-based approach to identify mild osteoarthritis (OA) of the knee. METHODS: Blood samples were drawn from 161 subjects, including 85 subjects with arthroscopically diagnosed mild OA of the knee and 76 controls. Following RNA isolation, an in-house custom cDNA microarray was used to screen for differentially expressed genes. A subset of selected genes was then tested using real-time RT-PCR. Logistic regression analysis was used to evaluate linear combinations of the biomarkers and receiver operating characteristic curve analysis was used to assess the discriminatory power of the combinations. RESULTS: Genes differentially expressed (3543 genes) between mild knee OA and control samples were identified through microarray analysis. Subsequent real-time RT-PCR verification identified six genes significantly down-regulated in mild OA: heat shock 90kDa protein 1, alpha; inhibitor of kappa light polypeptide gene enhancer in B-cells, kinase complex-associated protein; interleukin 13 receptor, alpha 1; laminin, gamma 1; platelet factor 4 (also known as chemokine (C-X-C motif) ligand 4) and tumor necrosis factor, alpha-induced protein 6. Logistic regression analysis identified linear combinations of nine genes--the above six genes, early growth response 1; alpha glucosidase II alpha subunit; and v-maf musculoaponeurotic fibrosarcoma oncogene homolog B (avian)--as discriminatory between subjects with mild OA and controls, with a sensitivity of 86% and specificity of 83% in a training set of 78 samples. The optimal biomarker combinations were then evaluated using a blind test set (67 subjects) which showed 72% sensitivity and 66% specificity. CONCLUSIONS: Linear combinations of blood RNA biomarkers offer a substantial improvement over currently available diagnostic tools for mild OA. Blood-derived RNA biomarkers may be of significant clinical value for the diagnosis of early, asymptomatic OA of the knee.

Adult↗
PubMed1997

The effects of vitamin C supplementation on biomarkers of oxygen radical generated damage in human volunteers with "low" or "high" cholesterol levels.

A human volunteer study was conducted to test the effect of vitamin C supplementation on biomarkers of oxygen radical-mediated damage in individuals with a range of serum cholesterol levels. A group of 48 non-smokers, 24 men and 24 women, was selected from a panel of over 100 volunteers to give as wide a range of serum cholesterol levels as possible. None of the volunteers was taking medication to control cholesterol levels and they maintained their normal dietary habits so as not to compromise their cholesterol status. Volunteers were allocated to three groups of 16, each consisting of four males with low cholesterol levels (< 6 mmol/L) matched for age and build with four males with high cholesterol levels (> 6 mmol/L) and eight females matched in the same way. A three-treatment, three-treatment period, cross-over design was adopted to take account of any temporal differences in response. The three treatments given were placebo, 60 mg vitamin C/day (the recommended daily allowance) and 6 g vitamin C/day. Each treatment was given for 14 days with 6 weeks between the treatment periods. All procedures were performed to the standards of Good Clinical Practice. Blood samples were taken at the end of each treatment period. Serum was assayed for cholesterol whilst vitamin C, total antioxidant capacity, lipid peroxidation breakdown products and ras p21 protein levels were measured in plasma. Lymphocytes were examined for DNA damage using the Comet assay and chromosome aberration test. The Comet assay was conducted with and without challenge with hydrogen peroxide and the chromosome aberration test with and without challenge with bleomycin. Vitamin C supplementation caused a statistically significant increase in plasma vitamin C concentrations and total antioxidant capacity but did not affect cholesterol levels or ras p21 protein levels. There was a non-significant dose-related decrease in lipid peroxidation breakdown products with vitamin C supplementation. No effect on DNA damage was observed in the Comet assay, either with or without hydrogen peroxide challenge, or in the chromosome aberration test without bleomycin. However, a statistically significant increase in bleomycin-induced aberrations was found after vitamin C supplementation. This may be due to effects of vitamin C on iron status. Comparison of male and female subjects showed statistically significant differences in plasma vitamin C levels, the antioxidant capacity of the plasma and the number of chromosome aberrations induced by bleomycin challenge of lymphocytes in vitro. The results were the same for both low and high cholesterol subjects. This study provides no evidence of a beneficial effect on any of the biomarkers studied of vitamin C supplementation over a short-term supplementation period of 2 weeks in a population of healthy, non-smoking individuals eating a nutritionally adequate diet.

Adult↗
PubMed1997

[GRH test].

Explore the source record for details and available documents.

Biomarkers↗
PubMedDate not supplied

New test predicts heart risk.

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1-Alkyl-2-acetylglycerophosphocholine Esterase↗
PubMed2001

Lipid peroxidation end products-responded induction of a preneoplastic marker enzyme glutathione S-transferase P-form (GST-P) in rat liver on admistration via the portal vein.

The in vivo induction mechanism of a preneoplastic marker enzyme, glutathione S-transferase P-form (GST-P), by a number of carcinogens and some noncarcinogens such as anti-oxidants [Proc. Natl. Acad. Sci. U.S.A. 85 (1984) 3964] has remained to be solved. Among the various administration routes tested, GST-P became immunohistochemically demonstrable in the liver centrilobular zone 3 after 24-48h on administration of prostaglandin J2's, 15-deoxy-Delta(12,14)-PGJ2, PGJ2 and Delta(12)-PGJ2 to male rats via the portal vein, whereby the animals had been pretreated with Soya oil intraperitoneally to exhaust fatty acid binding proteins. Unsaturated aldehydes, 4-hydroxynonenal, crotonaldehyde and acrolein, given by the same route induced putatively preneoplastic single cells positive for GST-P. As these lipid peroxidation end products are the substrates as well as inducers of the enzyme, its physiological function could be their detoxication. These results indicate that GST-P expression can be mediated through lipid peroxidation possibly accounting for induction observed with a wide variety of carcinogens. In addition, present method may also be of use as a direct, simple, rapid, and sensitive in vivo test in examination of other biological responses.

Animals↗
PubMed2003

Changes in serum biochemical responses during cardiac rehabilitation.

PURPOSE: The objective of the study was to establish the difference in the exercise response profile of the enzymes lactate dehydrogenase (LDH), lactate dehydrogenase isoenzyme 1 (LDH-1), creatine kinase (CK), and creatine kinase polypeptide subunit MB (CK-MB) after a 12-wk cardiac rehabilitation exercise program. METHODS: Nineteen male nonblockade recent postmyocardial infarction patients (PMIP), aged 60.7 +/- 6.5 yr, performed a graded exercise test on a motorized treadmill until volitional cessation or reaching any of the American College of Sports Medicine criteria. After this, a 12-wk exercise-based cardiac rehabilitation program was adopted at a frequency of 3x wk-1. Each subject was then retested using the same protocol and intensity. Blood samples were collected by venipuncture from the antecubital vein into Vacutainer tubes preexercise, immediately, postexercise, and 24 h later. The blood samples were then centrifuged to obtain serum before being transported to the laboratory for enzymatic analysis by conventional methods. RESULTS: a) a 12-wk cardiac rehabilitation exercise program had no influence on the serum activities of enzymes at rest; b) the same exercise reduced the enzyme activity level after training; and c) LDH and CK values returned to normal faster after the program. CONCLUSIONS: These findings provide further evidence for the benefits of exercise-based cardiac rehabilitation and demonstrate that an exercise test provokes a temporary serum enzyme response, which does not reflect myocardial damage.

Aged↗