Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99


Any time

2019 ( 11 )

2018 ( 18 )

2017 ( 29 )

2016 ( 31 )

Custom range...

Search Results: 1 - 10 of 1897 matches for " Assay "
All listed articles are free for downloading (OA Articles)
Page 1 /1897
Display every page Item
Molecular Study of Rickettsiae in Serum Cattle  [PDF]
Lourdes Lledó, Consuelo Giménez-Pardo, Rufino álamo
Open Journal of Preventive Medicine (OJPM) , 2018, DOI: 10.4236/ojpm.2018.88022
Abstract: A molecular survey of 230 serum samples from cattle was studied by PCR-amplification of the citrate synthase gene gltA, the gene coding for protein 190 kDa—ompA—and the gene ompB. The study was carried out in the Junta of Castilla y León (northern Spain). The results suggest that the molecular study of the serum cattle would not make a good method in epidemiological studies on rickettsiae in this region. But it is necessary to continue and expand the work with more sensitive molecular methods.
Antioxidant Activity Assessment and Color Analysis of Skin from Different Peach Varieties Grown in South Carolina  [PDF]
Yueyuan Zhang, Inyee Han, Paul Dawson
Food and Nutrition Sciences (FNS) , 2015, DOI: 10.4236/fns.2015.61003
Abstract: Peach skin is a byproduct from the further processing of fresh peaches with the potential to be recovered and utilized as a natural antioxidant. Color analysis, phenolic content and antioxidant activity of peach skin from 13 varieties of peaches grown in South Carolina were determined. Color analysis indicated that Norman, Cary Mac, Ruby Prince and Flame Prince differed from other varieties of peaches. Antioxidant activity of peach skin extracts were evaluated by the total phenolics (TP), DPPH free radical scavenging (DPPH), ferric reducing antioxidant power (FRAP) and ferrous ion chelating (FIC) assays. The range of total phenolics content was 8.38 - 18.81 (gallic acid equivalent mg/g dry weight). The total phenolic content was highly correlated to DPPH and FRAP activity in peaches ranging from 8 - 23 AE/mg and 5 - 12 AE/mg, respectively. Three peach varieties with skins having the greatest antioxidant capacity were Red Globe, Scarlet Prince, and O’Henry.
Newly Developed Endotoxin Measurement Method (the Endotoxin Activity Assay) May Reflect the Severity of Sepsis  [PDF]
Kiyohide Ishihata, Yasuyuki Kakihana, Tomotsugu Yasuda, Tohru Imabayashi, Norifumi Nakamura
Open Journal of Pathology (OJPathology) , 2013, DOI: 10.4236/ojpathology.2013.31001

Objectives: Endotoxin (ET) is a structural molecule of the Gram-negative bacilli extracellular membrance, which activates targeted cells including macrophages and neutrophils, and causes septic shock. But it is known that the conventional ET measurement method has many problems; for example, a discrepancy between plasma ET concentration and clinical manifestation in the septic patients has been reported. The purpose of this study was to evaluate the usefulness of a newly developed method (Endotoxin Activity Assay (EAA)) to measure the ET activity (EA) in patients under sepsis compared with the prior method of the limulus amebocyte lysate (LAL) assay and explore the association between EA levels and patients’ severity. Method: We measured the EA levels in 40 patients (aged 63.5 +/- 17.7 years) admitted to the ICU. EA level was measured using a chemiluminometer (Autolumat LB953; EG & Berthold). Patients were divided into 5 groups: 1) control group; 2) systemic inflammatory response syndrome (SIRS) group; 3) sepsis (SIRS and infection) group; 4) severe sepsis group and 5) septic shock group. We then compared the EA level between each group and control group. We made the statistical evaluation by unpaired t test and significant difference was p < 0.05. Results: The EA levels were significantly increased as sepsis severity rises. The measured EA levels were (0.18 +/- 0.09), (0.33 +/- 0.19), (0.39 +/- 0.16), (0.65 +/- 0.25) and (0.78 +/- 0.34) in control, SIRS, sepsis, severe sepsis and septic shock groups, respectively. In the EA level measured by EAA, severe patients had a tendency to exceed the cutoff value. Conclusion: The EA levels were significantly correlated as patients’ severity rise. Measuring EA levels on admission to ICU may provide a mechanism to identify and target severe septic patients.

The Antioxidant and Free Radical Scavenging Activities of Chlorophylls and Pheophytins  [PDF]
Ching-Yun Hsu, Pi-Yu Chao, Shene-Pin Hu, Chi-Ming Yang
Food and Nutrition Sciences (FNS) , 2013, DOI: 10.4236/fns.2013.48A001
Abstract: Chlorophylls are important antioxidants found in foods. We explored the mechanisms through which the a and b forms of chlorophyll and of pheophytin (the Mg-chelated form of chlorophyll) reduce oxidation: we used comet assay to measure prevention of H2O2 DNA damage; we tested for quenching of 1,1-diphenyl-2-picrylhydrazyl (DPPH); we measured the ability to chelate Fe(II); and, we tested their ability to prevent formation of thiobarbituric acid reactive substances (TBARS) during Cu-mediated peroxidation of low density lipoprotein (LDL) in a chemical assay. All chlorophylls and pheophytins showed significant dose-dependent activity in the assays, with the pheophytins being the strongest antioxidants. Thus, these chemicals can prevent oxidative DNA damage and lipid peroxidation both by reducing reactive oxygen species, such as DPPH, and by chelation of metal ions, such as Fe(II), which can form reactive oxygen species.
Non Specific Amplification with the LAMP Technique in the Diagnosis of Tuberculosis in Sri Lankan Settings  [PDF]
K. D. Senarath, R. B. Usgodaarachchi, V. Navaratne, A. Nagahawatte, C. D. Wijayarathna, J. Alvitigala, C. L. Goonasekara
Journal of Tuberculosis Research (JTR) , 2014, DOI: 10.4236/jtr.2014.24021
Abstract: Background: Tuberculosis (TB) remains a burden to Sri Lanka, where the incidence of the disease has been increasing over the past decade. The lack of early and accurate detection of the disease has been the main obstacle to its control. Microscopy or the culturing of mycobacteria from clinical samples is the most commonly used TB diagnostic tools in Sri Lanka. All these methods have their own limitations. Alternative diagnostic methods are therefore of high importance. Objectives: In this study, an attempt was made to validate loop mediated isothermal amplification (LAMP), which specifically amplifies a DNA sequence very rapidly at a low cost with limited resources. Methods: Crude DNA extractions of fifty culture isolates prepared from sputum samples, which were collected from patients with suspected TB extracts, were subjected to three separate LAMP assays. One assay was specific for 16S ribosomal RNA (16S rRNA) gene in genus Mycobacterium, and could detect the bacteria up to the genus level. The other two contained MTB specific primers targeting rimM or gyrB gene sequences in Mycobacterium tuberculosis (MTB), which enabled detection up to the species level. The sensitivity and specificity of the LAMP assays in the identification of mycobacteria or MTB were compared to microscopy and culture techniques. Results: Forty three out of the 47 Mycobacterium cultures were Mycobacterium-positive for LAMP assays with universal primers indicating a sensitivity of 92% in identifying Mycobacterium genus. However, thirteen out of 14 culture negatives were also positive with LAMP assays, which showed a specificity of only 7% in identifying MTB. The results suggested a high percentage of false positives by LAMP assays as compared to culture. Based on the colour changing of ZYBR Green dye and gel electrophoresis of the LAMP-amplified product, the detection of a non-specific amplification, even in the absence of target DNA, was recurrently observed. The result was the same even after following strict safety operations and laboratory practices to avoid the possibility of a cross-over contamination of MTB. Interestingly, this nonspecific DNA amplicon did not respond to digestion with BsaI restriction enzyme, suggesting that the false positives are not due to the presence of MTB. Conclusion: Under the tested conditions, the specificity of the LAMP method to identify MTB is low as compared to culture technique. Further investigations into optimizing the LAMP assay technique are required before it can be used, in its simple form, to diagnose TB in local clinical settings.
Antioxidant Activity Determination of Citronellal and Crude Extracts of Cymbopogon citratus by 3 Different Methods  [PDF]
Y. Lu, T. J. Khoo, C. Wiart
Pharmacology & Pharmacy (PP) , 2014, DOI: 10.4236/pp.2014.54047

Cymbopogon citratus, better known as lemongrass, is a plant commonly used for culinary purposes. It is known to contain the compound citronellal, which is responsible for the lemon-scent of many of the plants of the genus Cymbopogon. A chloroform extract of Cymbopogon citratus was screened to determine its free radical scavenging activities. Three different methods were used to test the antioxidant activity of the extract, including FRAP assay (Ferric reducing antioxidant potential), DPPH radical scavenging assay (1,1-diphenyl-2-picryl hydrazyl radical reducing power methods), and β-carotene bleaching assay. Cymbopogon citratus showed low radical scavenging activities compared to ascorbic acid, gallic acid and quercetin. The results obtained suggest that Cymbopogon citratus is best appreciated for its refreshing aroma and delicate taste, but has little to offer as a source of antioxidants.

Screening for Genotoxicity and Oestrogenicity of Endocrine Disrupting Chemicals in Vitro  [PDF]
Karthryn M. Quinn-Hosey, James J. Roche, Andrew M. Fogarty, Concepta A. Brougham
Journal of Environmental Protection (JEP) , 2012, DOI: 10.4236/jep.2012.328105
Abstract: A diverse range of endocrine disrupting chemicals (EDCs) was examined, using an in vitro test system, for critical events required for the onset of carcinogenesis in vivo. The initiation stage of carcinogenesis is a genotoxic process. 4-Octylphenol (alkylphenol), bisphenol A (plasticiser), coumestrol and genistein (phytoestrogens), 2,4-dichlorophe- noxyacetic acid and toxaphene (pesticides) and ethinylestradiol (synthetic hormone) were investigated for potential mutagencicity, DNA strand breakage, clastogenicity and DNA repair. Significant induction in the percentage of cells containing micronuclei was observed for all the EDCs. Toxaphene and coumestrol were mutagenic in the Ames assay. They also induced significant levels of unscheduled DNA synthesis and DNA strand breakage. Bisphenol A induced low level DNA strand breakage in HepG2 cells in the comet assay. The EDCs, with the exception of toxaphene, induced transcriptional activation in the yeast estrogen screen (YES) assay. They were potently oestrogenic in the mammalian based MVLN (transactivation) and E-SCREEN (proliferation) assays. This report on the transactivational, proliferative and genotoxic ability of the EDCs suggests that these chemicals may play a role in the etiology of male and female reproductive cancers.
S.Y. Seyedna ; M. Sheidai
Iranian Journal of Public Health , 1996,
Abstract: Testosterone level was determined in six different populations of Iran using saliva steroid assay. Significant difference was observed in morning and afternoon testosterone level of the same individual (P>0.00l) significant difference was also noticed among different regions studied (P>0.00 1). Comparisons between alcoholics and nonalcoholic as well as smokers and nonsmokers showed significant difference in most of the cases.
Anti-oxidant activity and cytotoxicity of ethanolic extracts from rhizome of Musa acuminata  [PDF]
KPS Adinarayana, P Ajay Babu
Natural Science (NS) , 2011, DOI: 10.4236/ns.2011.34037
Abstract: In the present study, antioxidant activities of rhizome of Musa acuminata were investigated. Free radical scavenging assay (DPPH) and reducing power of the ethanolic extract of banana rhizome resulted in potential antioxidant activities. A relatively high percentage of antioxidant activity by DPPH assay (81.41% at 200 μg/ml) which was comparable to that of the standard, ascorbic acid at 100 μg/ml was observed. With the gallic acid as standard the extract showed a relatively low reductive potential, however, when tested for cytotoxicity at the highest concentration of the tested dose (256 μg/ml), the maximum rate of inhibition observed was 50.32%. The present work indicates that the ethanolic extract of Musa acuminata exhibits significant antiproliferative and antioxidant activities.
Simple, Inexpensive and Ecologically Friendly Derivative Spectrophotometric Fluconazole Assay from Nail Lacquer Formulations  [PDF]
Alisa Elezovi?, Amar Elezovi?, Sabira Had?ovi?
American Journal of Analytical Chemistry (AJAC) , 2011, DOI: 10.4236/ajac.2011.22012
Abstract: Nail lacquers represent new drug form specifically designed to treat infected nail plate. They are complex organic solutions with specific assaying problems due to the high content of the polymer and plasticizer. Furthermore, there is a lack of assaying methods of active substances from this type of formulations in scientific literature. We developed derivative UV-spectrophotometric method for determination of fluconazole content in antifungal nail lacquer formulations. The method was validated for specificity, linearity, precision (repeatability), intermediate precision and accuracy (recovery). The method is specific, linear in the range of 99.53 - 497.65 μg/ml, precise and showed good recovery (98.79% - 101.77% from all six developed formulations). Besides, it is inexpensive, simple and nontoxic, i.e. ecologically acceptable. This method can be used for assaying fluconazole from this type of formulations.
Page 1 /1897
Display every page Item

Copyright © 2008-2017 Open Access Library. All rights reserved.