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Results for “Detection technology”

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At least 469 records · Page 26Linked to original sources

PubMed2005

Single nucleotide polymorphisms detection based on DNA microarray technology: HLA as a model.

The significance of DNA variations among individuals, including single nucleotide polymorphisms (SNPs) and/or genome nucleotide mutations as well as to their detection by using new technology, will improve and facilitate the knowledge of each gene sequence. Microarray may provide information about thousands of gene simultaneously, leading to a more rapid and accurate genotyping. In this view, we developed a new methodology as an example for the detection of SNPs based on DNA microarray, using a panel of HLA alleles representative of loci A, B, DRB1. A panel of 180 oligonucleotide probes was selected to identify polymorphic positions located in exons 2 and 3 of HLA-A and B, and in exon 2 of HLA-DRB1 locus. Each oligonucleotide sequence was designed with a nucleotide mismatch located in the same position as the center of the hybridization sequence. Hybridization experiments were carried out with genomic probes constructed with an asymmetric PCR strategy. The amplified DNAs were obtained from bone marrow cells of donors previously typed for transplant. The results obtained were showing that the method was reliable thus providing a feasible technique both for HLA typing and for the investigation of other regions of genetic and clinical interest including polymorphisms correlated with different autoimmune diseases.

Alleles↗

PubMed1998

Common DNA sequences with potential for detection of genetically manipulated organisms in food.

Foods produced by genetic engineering technology are now appearing on the market and many more are likely to emerge in the future. The safety aspects, regulation, and labelling of these foods are still contentious issues in most countries and recent surveys highlight consumer concerns about the safety and labelling of genetically modified food. In most countries it is necessary to have approval for the use of genetically manipulated organisms (GMOs) in the production of food. In order to police regulations, a technology to detect such foods is desirable. In addition, a requirement to label approved genetically modified food would necessitate a monitoring system. One solution is to 'tag' approved GMOs with some form of biological or genetic marker, permitting the surveillance of foods for the presence of approved products of genetic engineering. While non-approved GMOs would not be detected by such a surveillance, they might be detected by a screen for DNA sequences common to all or most GMOs. This review focuses on the potential of using common DNA sequences as detection probes for GMOs. The identification of vector sequences, plant transcription terminators, and marker genes by PCR and hybridization techniques is discussed.

Base Sequence↗

PubMed2005

Electronic microarray analysis of 16S rDNA amplicons for bacterial detection.

Electronic microarray technology is a potential alternative in bacterial detection and identification. However, conditions for bacterial detection by electronic microarray need optimization. Using the NanoChip electronic microarray, we investigated eight marine bacterial species. Based on the 16S rDNA sequences of these species, we constructed primers, reporter probes, and species-specific capture probes. We carried out two separate analyses for longer (533 bp) and shorter (350 and 200 bp) amplified products (amplicons). To detect simultaneously the hybridization signals for the 350- and 200-bp amplicons, we designed a common reporter probe from an overlapping sequence within both fragments. We developed methods to optimize detection of hybridization signals for processing the DNA chips. A matrix analysis was performed for different bacterial species and complementary capture probes on electronic microarrays. Results showed that, when using the longer amplicon, not all bacterial targets hybridized with the complementary capture probes, which was characterized by the presence of false-positive signals. However, with the shorter amplicons, all bacterial species were correctly and completely detected using the constructed complementary capture probes.

Bacteria↗

PubMed2006

A tagging-via-substrate technology for genome-wide detection and identification of farnesylated proteins.

Protein farnesylation is one of the most common lipid modifications and has an important role in the regulation of various cellular functions. We have recently developed a novel proteomics strategy, designated the tagging-via-substrate (TAS) approach, for the detection and proteomic analysis of farnesylated proteins. This chapter describes the principle of TAS technology and details the method for detection and enrichment of farnesylated proteins.

Animals↗

PubMedDate not supplied

MALDI mass spectrometry for direct tissue analysis: a new tool for biomarker discovery.

The direct analysis of tissue sections by MALDI mass spectrometry holds tremendous potential for biomarker discovery. This technology routinely allows many hundreds of proteins to be detected over a mass range of approximately 2000-70 000 Da while maintaining the spatial localization of the proteins detected. This technology has been applied to a wide range of tissue samples, including human glioma tissue and human lung tumor tissue. In many cases, biostatistical analyses of the resulting protein profiles revealed patterns that correlated with disease state and/or clinical endpoints. This work serves as a review of recent applications and summarizes the current state of technology.

Animals↗

PubMed2004

Contrast-agent detection and quantification.

The Cadence contrast pulse sequencing (CPS) technology offers improved clinical information and workflow efficiency during contrast agent examinations. The technology harnesses unique non-linear microbubble energy discovered within the same fundamental frequency band as the transmitted pulses of sound and thus offers improved sensitivity and penetration. An auto tracking contrast quantification (ACQ) technology further complements the CPS detection technology with automatic image alignment during quantification with features such as on-line multiple time intensity curves (TIC). The regional image analysis holds promise of alleviating workflow inefficiency associated with manual alignment of image frames.

Contrast Media↗

PubMed2003

Renewable standard reference material for the detection of TP53 mutations.

BACKGROUND: Numerous DNA-based tests are currently in use or under development for the detection of mutations associated with disease. Most of the current methods use PCR amplification technologies and detection after separation or chromatography of the products. We have developed a panel of standard reference materials consisting of 12 plasmid clones containing a 2.0 kb region of the TP53 gene, including exons 5-9. Eleven of these clones contain a single mutation within the mutational hot spots of the TP53 gene, the twelfth is wild-type in this region of the gene. The mutations are amino acid (aa) 128: C to T; aa 175: G to A; aa 237: T to C; aa 245: G to A; aa 248: C to T; aa 248: G to A; aa 249: G to T; aa 273: C to T; aa 273: G to A; aa 282: C to T; and aa 328: T to C. These standard reference materials (SRMs), created by site-directed mutagenesis of wild-type TP53 from a human cell line, include the specific mutations most commonly found to be associated with cancer. Their use will improve disease detection by serving as validation materials to monitor errors in measurement methods, including PCR amplification, amplicon separation, and data analysis from different technology platforms. METHODS AND RESULTS: The single point mutations of the panel were validated by capillary electrophoresis single-strand conformational polymorphism analysis, denaturing gradient gel electrophoresis, and denaturing high-performance liquid chromatography, as well as full sequence analysis of both DNA strands of the cloned material. For both heteroduplex analysis methods, the presence of the mutations was resolved for each SRM. CONCLUSION: The generation of a standard TP53 reference panel and demonstration that the panel can successfully validate mutation detection across different mutation scanning technology platforms. Hence, this panel functions as an SRM to normalize results obtained from different laboratories using different techniques.

Base Sequence↗

PubMed1991

Pathobiology of papillomavirus-related cervical diseases: prospects for immunodiagnosis.

In recent years, the relationship between human papillomaviruses (HPV) and genital neoplasia has been explored intensively, and a molecular basis for the role of HPV in the genesis of these diseases has been convincingly demonstrated. These findings have provided justification for efforts to apply this molecular information to the early detection and possible prevention of HPV-related neoplasia. The technology of detecting viral nucleic acids in genital fluids brought with it initial hopes that it would serve to identify women at risk for having or developing precancers or cancers of the cervix. Subsequent studies, however, have demonstrated limitations of the technology for predicting future disease. Recently, molecular immunology has complemented these prior efforts, with the intent to identify serological indices of exposure to HPV and perhaps delineate individuals at risk. The molecular basis for this approach, its limitations, and future prospects for immunodiagnosis are the subject of this review.

Condylomata Acuminata↗

PubMed2005

Application of silicon sensor technologies to tumor tissue in vitro: detection of metabolic correlates of chemosensitivity.

Silicon sensor technologies, developed during the 1990s, allow measurement of extracellular chemical changes related to cell metabolism. Exposition of tumor cells in vitro to anticancer drugs modifies cell metabolism, making it possible to detect on-line with sensor chips patterns of metabolic activity, which depend on drug sensitivity, or drug resistance of the cells. Sensor devices are composed of an incubation chamber with a sensor chip and a fluidic system for medium supply. Basically, two sensor types are available: (1) monosensor systems to detect extracellular acidification; and (2) multisensor arrays for many parameters such as pH, oxygen consumption, and impedance. Two companies have developed such systems: Molecular Devices (USA) and Bionas (Germany). In this chapter, in addition to operation of the sensor devices, we describe techniques for tissue (tumor and non-tumor) preparation. Basically, three procedures are described: (1) tissue dissociation and further cultivation on the sensor chip or on Transwell inserts; (2) preparation of tissue slices (300 microm thick) and attachment to the sensor chip or to inserts, and (3) cultivation of cells in dialysis tubes, a procedure necessary for nonadherent cells and cell suspensions to avoid their washing away. Evaluation of results and selection of controls are also discussed.

Antineoplastic Agents↗

PubMed1992

Continuous, on-line DNA sequencing using a versatile infrared laser scanner/electrophoresis apparatus.

A new apparatus for continuously detecting fluorescently labeled DNA fragments is based on infrared fluorescence technology. This technology combines state-of-the-art developments in chemistry, laser technology, and detection, while achieving improved reliability, sensitivity, and flexibility for applications including DNA sequencing. DNA molecules labeled with a novel infrared fluorophore are detected during electrophoresis using a scanning infrared fluorescence microscope. The microscope consists of a laser diode for exciting the fluorophore and a silicon avalanche photodiode for detecting the infrared emission. Optimum conditions for detection and throughput are obtained by adjusting electrophoresis, scanning and imaging parameters. Typical DNA sequencing runs (test templates) allow identification of over 500 bases per sample with greater than 99% accuracy.

Base Sequence↗

PubMed2003

Chapter 12: Human papillomavirus technologies.

Currently, human papillomavirus (HPV) DNA tests validated in large trials and epidemiological studies are the hybrid capture second-generation (HC2) HPV DNA assay and a variety of polymerase chain reaction (PCR) protocols employing degenerate or consensus primers. This article describes the currently available technology for HPV detection and discusses novel technologies and their potential for large-scale screening. Ideally, an HPV test should allow detection of multiple HPV types, identify individual types, and provide quantitative information about the viral load of each individual type found. Moreover, it should be easy to perform, be highly reproducible, with a high specificity and sensitivity, and amenable for high throughput analysis and automation. Because we do not yet fully understand the true value of viral load and the biological relevance of the different HPV types, any HPV test should be able to detect the clinically relevant high-risk types with a sufficient sensitivity of at least 10 000 genome copies per sample. To validate the different current and future test systems and to compare inter-laboratory performance we urgently need reference samples, validated reagents, and standardized protocols.

Biotechnology↗

PubMed2006

Essential role for gene profiling analysis in the authentication of human cell lines.

Cross-contamination between cultured cell lines can result in the generation of erroneous scientific data. Hence, it is very important to eliminate cell lines that are of an origin different from that being claimed. Inter-species contamination can be detected by various established methods, such as karyotype and isozyme analyses. However, it has been impossible to detect intraspecies cross-contamination prior to the development of technology to detect differences between cell lines at the molecular level. Recently, profiling of short tandem repeat (STR) polymorphisms has been established as a method for the analyses of gene polymorphism. Gene profiling by STR polymorphism (STR profiling) is a simple and reliable method to identify individual cell lines. Each human cell line currently provided by the Cell Engineering Division of the RIKEN BioResource Center was analyzed by STR profiling to authenticate its identity. We found that more than 10 human cell lines out of approximately 400 were in fact identical to a different cell line deposited in the collection, and therefore had been misidentified. We conclude that STR profiling is a useful and powerful method for eliminating cell lines that have been misidentified by cross-contamination or by other causes. Hence, STR profiling of human cell lines used in published research will likely be a prerequisite for publication in the future, so that the problem of misidentification of cell lines can be eliminated.

Cell Line↗

PubMed2001

Comparison of Light-Cycler PCR, enzyme immunoassay, and tissue culture for detection of herpes simplex virus.

A rapid PCR method was developed using the Roche LightCycler technology for detection of Herpes Simplex Virus I and II. The Lightcycler method was compared with tissue culture and direct HSV antigen detection using routine clinical samples. The LightCycler PCR was shown to be more sensitive than isolation by tissue culture (sensitivity of culture versus PCR 78%) and HSV antigen detection (sensitivity of EIA versus PCR 56%). The amplified product may be typed without additional tests. The LightCycler PCR method provides a rapid method for HSV detection that correlates well with established tests.

Animals↗

PubMed2005

Detection and identification of stable oligomeric protein complexes in Escherichi coli inner membranes: a proteomics approach.

In this study we present a new technology to detect stable oligomeric protein complexes in membranes. The technology is based on the ability of small membrane-active alcohols to dissociate the highly stable homotetrameric potassium channel KcsA. It is shown via a proteomics approach, using diagonal electrophoresis and nano-flow liquid chromatography coupled to tandem mass spectrometry, that a large number of both integral and peripheral Escherichia coli inner membrane proteins are part of stable oligomeric complexes that can be dissociated by small alcohols. This study gives insight into the composition and stability of these complexes.

Bacterial Proteins↗

PubMed2001

Real-time detection of L-ascorbic acid and hydrogen peroxide in crude food samples employing a reversed sequential differential measuring technique of the SIRE-technology based biosensor.

Detection of the common electrochemical interferents, ascorbic acid and hydrogen peroxide, using a SIRE (Sensors based on Injection of the Recognition Element) technology based biosensor in reverse mode operation is reported. The differential measuring principle employed in the SIRE biosensor during operation in reverse mode is such that the sample is measured first in the presence of enzyme (yielding matrix signal only), and then measured again in the absence of enzyme (yielding signal from matrix+analyte). Subtraction of the signal obtained in the presence of enzyme from the signal obtained in the absence of enzyme gives a specific signal for the analyte only and correlates directly to its concentration in solution. The linear range for the determination of ascorbic acid and hydrogen peroxide was 0-3 mM and 0-2 mM, respectively, with an enzyme concentration of 25 U ascorbate oxidase/ml and 1000 U catalase/ml. The reproducibility was 5% for ascorbic acid (R.S.D. n=15) and 10% for hydrogen peroxide (R.S.D. n=18). The cost per measurement was 0.28 USD for ascorbic acid analysis and 0.0008 USD for hydrogen peroxide analysis. The degradation of ascorbic acid in cereal was followed in real-time, as was the stabilization of low pH on the degradation process.

Ascorbate Oxidase↗

PubMed2003

Population stratification and spurious allelic association.

Great efforts and expense have been expended in attempts to detect genetic polymorphisms contributing to susceptibility to complex human disease. Concomitantly, technology for detection and scoring of single nucleotide polymorphisms (SNPs) has undergone rapid development, extensive catalogues of SNPs across the genome have been constructed, and SNPs have been increasingly used as a means for investigation of the genetic causes of complex human diseases. For many diseases, population-based studies of unrelated individuals--in which case-control and cohort studies serve as standard designs for genetic association analysis--can be the most practical and powerful approach. However, extensive debate has arisen about optimum study design, and considerable concern has been expressed that these approaches are prone to population stratification, which can lead to biased or spurious results. Over the past decade, a great shift has been noted, away from case-control and cohort studies, towards family-based association designs. These designs have fewer problems with population stratification but have greater genotyping and sampling requirements, and data can be difficult or impossible to gather. We discuss past evidence for population stratification on genotype-phenotype association studies, review methods to detect and account for it, and present suggestions for future study design and analysis.

Alleles↗

PubMed2003

Strategies and solid-phase formats for the analysis of protein and peptide phosphorylation employing a novel fluorescent phosphorylation sensor dye.

Protein kinases represent one of the largest families of regulatory enzymes, with more than 2,000 of them being encoded for by the human genome. Many cellular processes are regulated by the reversible phosphorylation of proteins and upwards of 30% of the proteins comprising the eukaryotic proteome are likely to be phosphorylated at some point during their existence. In the past, analysis of global protein phosphorylation has been accomplished through radiolabelling of samples with inorganic (32P or [gamma-32)P] ATP. The approach is limited to specimens amenable to radiolabelling and poses certain safety and disposal problems. Alternatively, immunodetection with antibodies to the common phosphoamino acids may be employed, but the antibodies are relatively expensive and exhibit limited specificity and a certain degree of cross-reactivity. Pro-Q Diamond dye is a new fluorescent phosphosensor technology suitable for the detection of phosphoserine-, phosphothreonine- and phosphotyrosine-containing proteins directly in isoelectric focusing gels, SDS-polyacrylamide gels and two-dimensional gels. Additionally, the technology is appropriate for the detection of phosphoproteins or phosphopeptides arrayed on protein chips or affixed to beads. Dye-stained proteins and peptides can be excited with a laser-based light source of 532 or 543 nm or with a xenon-arc lamp-based system equipped with appropriate band pass filters. Alternatively, ultraviolet light of about 302 nm may be employed, providing that sufficiently long exposure times are used to collect the fluorescence signal. Pro-Q Diamond dye emits maximally at approximately 580 nm. The fluorescence-based detection technology is easy to conduct, cost effective and allows rapid large-scale screening of protein and peptide phosphorylation in a variety of solid-phase assay formats.

Electrophoresis, Polyacrylamide Gel↗

PubMedDate not supplied

Radiation cytogenetics: from chromosomes to single nucleotides and from metaphase cells to tissues.

This paper provides a broad overview of radiation cytogenetics that is divided into four sections. The first section provides a brief history of metaphase-based analyses for detecting and quantifying human exposure to ionizing radiation. The second section describes technologies for detecting cellular responses to radiation exposure other than DNA damage. The third section discusses molecular cytological approaches for analyzing some of the long-term effects of radiation exposure in tissues, including tumors. The final section provides a look towards the future and makes recommendations including suggestions for technological innovations that would enhance the field of radiation cytology.

Animals↗