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Real-time Analysis (real-time + analysis)

Distribution by Scientific Domains
Life Sciences60%

Selected Abstracts

Rapid saliva processing techniques for near real-time analysis of salivary steroids and protein

JOURNAL OF CLINICAL LABORATORY ANALYSIS, Issue 6 2008
Kelly R. Atkinson
Abstract Introduction: Point-of-care (POC) measurements using saliva samples have immense potential to assess systemic health and wellbeing, but sample viscosity and contaminants can affect analyses. We sought a portable clean-up method for whole saliva appropriate for use with POC measurement techniques such as biosensors. Methods: Whole saliva from each of 13 male subjects was split into 5 fractions. Each fraction was treated with a different clean-up process: a freeze,thaw,centrifuge (FTC) step; centrifugation alone; or passage through a Mini-UniPrep polyethersulfone filter, cotton Salivette®, or foam Oracol device. Following clean-up, each subject's treated saliva fractions were assayed for cortisol, testosterone, dehydroepiandrosterone (DHEA), and proteinconcentrations. The effects of clean-upmethods on nonspecific binding (NSB) in a biosensor were also assessed. Results: Compared with FTC, no analytes were affected by centrifugation alone. Cotton Salivettes significantly altered all analytes, with increases in cortisol (+64%), testosterone (+126%), and DHEA (off-scale) levels, and decreased protein (,21%) and biosensor NSB (,75%). Oracol foam devices decreased DHEA levels by 28%. Mini-UniPrep filtration decreased testosterone (,45%) and DHEA (,66%) concentrations while increasing cortisol (+40%). Conclusion: No method was optimal for all analytes, highlighting the need for validation of saliva treatment methods before their adoption in rapid POC analyses. J. Clin. Lab. Anal. 22:395,402, 2008. © 2008 Wiley-Liss, Inc. [source]

Clinical and virological characteristics of lamivudine resistance in chronic hepatitis B patients: A single center experience

JOURNAL OF MEDICAL VIROLOGY, Issue 3 2005
Jian Sun
Abstract We have investigated the characteristics of lamivudine-resistant strains in patients with chronic hepatitis B in Guangdong, China, where the predominant genotypes are B and C. Two hundred forty-seven patients treated with lamivudine in Nanfang Hospital were followed-up. Patients with hepatitis B e antigen (HBeAg) positive and hepatitis B virus (HBV)-DNA levels over 7.5,×,106 copies/ml at baseline had a shorter time to the selection of YMDD mutant (P,=,0.02 and 0.00, respectively). The detection of YMDD mutant precedes HBV-DNA breakthrough and alanine transaminase (ALT) flare in about 2 and 3 months, respectively. The ALT flare after the appearance of YMDD mutants was more evident in HBeAg positive patients than HBeAg negative patients (P,=,0.02). After emergence of YMDD mutant, the HBV-DNA level was significantly higher in genotype C patients compared with genotype B patients (P,=,0.02). No significant difference of YMDD mutant pattern was found between patients with genotype B and C. Four kinds of new mutants were found in over two patients including rtL80I, rtG172E, rtG174C, and rtG172E/rtG174C. In vitro transfection and real-time analysis showed that rtG172E, rtG174C, and rtG172E/rtG174C mutants had a decreased replication competence compared with wild type (33%, 27%, and 15% of the wild type HBV, respectively). Our result suggest that genotypic monitoring of YMDD mutant is important for the management of patients treated with lamivudine. J. Med. Virol. 75:391,398, 2005. © 2005 Wiley-Liss, Inc. [source]

The dynamic microbe: green fluorescent protein brings bacteria to light

MOLECULAR MICROBIOLOGY, Issue 5 2002
Carolyn M. Southward
Summary The demonstration that the green fluorescent protein (GFP) from the jellyfish Aequorea victoria required no jellyfish-specific cofactors and could be expressed as a fluorescent protein in heterologous hosts including both prokaryotes and eukaryotes sparked the development of GFP as one of the most common reporters in use today. Over the past several years, the utility of GFP as a reporter has been optimized through the isolation and engineering of variants with increased folding rates, different in vivo stabilities and colour variants with altered excitation and emission spectral properties. One of the great utilities of GFP is as a probe for characterizing spatial and temporal dynamics of gene expression, protein localization and protein,protein interactions in living cells. The innovative application of GFP as a reporter in bacteria has made a significant contribution to microbial cell biology. This review will highlight recent studies that demonstrate the potential of GFP for real-time analysis of gene expression, protein localization and the dynamics of signalling transduction pathways through protein,protein interactions. [source]

Development of biosensor based on imaging ellipsometry

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 4 2008
G. Jin
Abstract The concept of biosensor based on imaging ellipsometry was proposed ten years ago. Its principle and the methodology as well as some solutions to problems which have to be faced during the development are mentioned. Its properties of phase sensitive, high throughput and fast sampling, as well as label-free, sensitivity better than 1 ng/ml for Immunoglobulin G, and real-time analysis for protein interaction process, etc. provide a potential for applications in biomedicine field. The recent biosensing development with total internal reflection imaging ellipsometry is presented also. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Quantitative real-time analysis of HIV-1 gene expression dynamics in single living primary cells

BIOTECHNOLOGY JOURNAL, Issue 6 2006
Asier Sáez-Cirión
Abstract Studies on the regulation of viral transcription upon infection of the target cells have provided important information on the viral and host factors that influence pathogenesis. However, these studies have been limited so far to steady-state analysis of gene expression. Here we report an image based photon-counting method that allows real-time quantitative imaging of viral gene expression in infected single cells. Employing an HIV-1 vector bearing the firefly luciferase reporter gene, we exploited a single cell photon imaging methodology (a customized and highly sensitive imaging microscope) to measure viral gene expression following integration into a host genome in situ. Our approach reveals real-time dynamics of viral gene expression in living HIV natural target cells (primary human CD4 T cells and macrophages), and promises itself as a powerful tool for quantitative studies on a wide variety of virus-host cell interactions. [source]