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At least 415 records · Page 23Linked to original sources

PubMed2006

Thin-film technology for direct visual detection of nucleic acid sequences: applications in clinical research.

Certain optical conditions permit the unaided eye to detect thickness changes on surfaces on the order of 20 A, which are of similar dimensions to monomolecular interactions between proteins or hybridization of complementary nucleic acid sequences. Such detection exploits specific interference of reflected white light, wherein thickness changes are perceived as surface color changes. This technology, termed thin-film detection, allows for the visualization of subattomole amounts of nucleic acid targets, even in complex clinical samples. Thin-film technology has been applied to a broad range of clinically relevant indications, including the detection of pathogenic bacterial and viral nucleic acid sequences and the discrimination of sequence variations in human genes causally related to susceptibility or severity of disease.

Base Sequence↗

PubMed2005

Protein-detecting microarrays: current accomplishments and requirements.

The sequencing of the human genome has been successfully completed and offers the chance of obtaining a large amount of valuable information for understanding complex cellular events simply and rapidly in a single experiment. Interestingly, in addressing these proteomic studies, the importance of protein-detecting microarray technology is increasing. In the coming few years, microarray technology will become a significantly promising and indispensable research/diagnostic tool from just a speculative technology. It is clear that the protein-detecting microarray is supported by three independent but strongly related technologies (surface chemistry, detection methods, and capture agents). Firstly, a variety of surface-modification methodologies are now widely available and offer site-specific immobilization of capture agents onto surfaces in such a way as to keep the native conformation and activity. Secondly, sensitive and parallel detection apparatuses are being developed to provide highly engineered microarray platforms for simultaneous data acquisition. Lastly, in the development of capture agents, antibodies are now probably the most prominent capture agents for analyzing protein abundances. Alternative scaffolds, such as phage-displayed antibody and protein fragments, which provide the advantage of increasing diversity of proteinic capture agents, however, are under development. An approach involving recombinant proteins fused with affinity tag(s) and coupled with a highly engineered surface chemistry will provide simple production protocols and specific orientations of capture agents on the microarray formats. Peptides and other small molecules can be employed in screening highly potent ligands as well as in measuring enzymatic activities. Protein-detecting microarrays supported by the three key technologies should contribute in accelerating diagnostic/biological research and drug discovery.

Animals↗

PubMedDate not supplied

Detecting adverse events using information technology.

CONTEXT: Although patient safety is a major problem, most health care organizations rely on spontaneous reporting, which detects only a small minority of adverse events. As a result, problems with safety have remained hidden. Chart review can detect adverse events in research settings, but it is too expensive for routine use. Information technology techniques can detect some adverse events in a timely and cost-effective way, in some cases early enough to prevent patient harm. OBJECTIVE: To review methodologies of detecting adverse events using information technology, reports of studies that used these techniques to detect adverse events, and study results for specific types of adverse events. DESIGN: Structured review. METHODOLOGY: English-language studies that reported using information technology to detect adverse events were identified using standard techniques. Only studies that contained original data were included. MAIN OUTCOME MEASURES: Adverse events, with specific focus on nosocomial infections, adverse drug events, and injurious falls. RESULTS: Tools such as event monitoring and natural language processing can inexpensively detect certain types of adverse events in clinical databases. These approaches already work well for some types of adverse events, including adverse drug events and nosocomial infections, and are in routine use in a few hospitals. In addition, it appears likely that these techniques will be adaptable in ways that allow detection of a broad array of adverse events, especially as more medical information becomes computerized. CONCLUSION: Computerized detection of adverse events will soon be practical on a widespread basis.

Accidental Falls↗

PubMed2004

Detection and quantitation of genetically modified maize (Bt-176 transgenic maize) by applying ligation detection reaction and universal array technology.

We have applied the ligation detection reaction (LDR) combined with a universal array approach to the detection and quantitation of the polymerase chain reaction (PCR) amplified cry1A(b) gene from Bt-176 transgenic maize. We demonstrated excellent specificity and high sensitivity. Down to 0.5 fmol (nearly 60 pg) of PCR amplified transgenic material was unequivocally detected with excellent linearity within the 0.1-2.0% range with respect to wild-type maize. We suggest the feasibility of extending the LDR/universal array format to detect in parallel several transgenic sequences that are being developed for food applications.

Bacillus thuringiensis Toxins↗

PubMed2003

[New technologies in the prevention, detection, diagnosis and treatment of tuberculosis in children].

If the epidemiological situation is tense, new technologies should be developed and put into practice to enhance the efficiency of specific prevention, early detection, diagnosis and treatment of tuberculosis in children. There is evidence for the high efficacy and low reactogenicity of lower antigenicity-loading BCG-M vaccine that causes a 15-fold decrease in infant morbidity, as compared with that among non-vaccinated children, and this vaccine shows a 5-fold reduction in postvaccination complications as compared with BGC vaccine. The 26-year use of tuberculin diagnosis via Mantoux test with 2TE PPD-L during mass vaccination of children and adolescents has proved itself in early identification of tuberculosis and risk groups. A new risk group has been identified. This includes children with increasing tuberculin reactions; three-month intermittent chemoprevention with isoniazid reduces tuberculin sensitivity in the children and prevents tuberculosis in them. The developed short-term (6-9 months) courses of chemotherapy in preschool and school children by using drugs (isoniazid + rifampicin + pyrazinamide) yield the best healing without residual changes of uncomplicated forms of tuberculosis in 83 and 60% of the children with complicated events, respectively. The chemotherapy regimens have been divided into 4 groups of different dosage schedules.

Antitubercular Agents↗

PubMed2000

A novel, sensitive detection system for high-density microarrays using dendrimer technology.

To improve signal detection on cDNA microarrays, we adapted a fluorescent oligonucleotide dendrimeric signal amplification system to microarray technology. This signal detection method requires 16-fold less RNA for probe synthesis, does not depend on the incorporation of fluorescent dNTPs into a reverse transcription reaction, generates a high signal-to-background ratio, and can be used to allow for multichannel detection on a single chip. Furthermore, since the dendrimers can be detected individually, it may be possible, by employing dendrimer-binding standards, to calculate the numbers of bound cDNAs can be estimated. These features make the dendrimer signal detection reagent ideal for high-throughput functional genomics research.

Biotechnology↗

PubMed2004

Detection and staging of esophageal cancers.

PURPOSE OF REVIEW: Technology for detection and staging of esophageal cancer has made significant strides advances in the past 2 years. These advances have led to the enhanced selection of appropriate treatments for esophageal cancer. Cancers that are discovered at an early stage can be treated with endoscopic therapy, whereas advanced cancers are primarily treated with chemotherapy and radiation. RECENT FINDINGS: Detection of esophageal cancer can be enhanced by two major mechanisms: one is by enhancing the lesion, which has typically been done using vital dyes and the other is by changing the method of imaging of the lesion, which has been accomplished by the use of several technologies including fluorescence and optical coherence tomography. Neither of these techniques has been proven, but some investigators have been able to use them to enhance cancer detection. Similar technologies have been applied to staging esophageal cancer. The optical imaging devices also have the potential to stage mucosa-based malignancy. The use of positron emission tomography has been the most recent development that may have application for advanced cancer. Endoscopic ultrasonography has also been improved in resolution and ability to perform fine needle aspiration. The most significant development for staging early cancers is mucosal resection. Finally, by using mucosal resection techniques, the depth of tumor invasion can be established by histology, which allows gastroenterologists to treat early cancers with greater confidence regarding rates of metastatic disease. SUMMARY: Early detection of esophageal cancer can be enhanced by the use of vital dyes for mucosal staining, but the advancement of novel optical diagnostic strategies may be more suitable for clinical use. The primary advantage of these new staging methods is to clearly identify early stage cancer that potentially can be treated without traditional surgical resection techniques. More advanced cancers can be staged with positron emission tomography, but definitive studies demonstrating its role are still lacking.

Journal Article↗

PubMed2006

[DNA-technologies application for early detection of caries predisposition].

In the paper the possible use of modern DNA-technologies for estimation of gene pool, dental hard tissue resistance to caries prognosis, hereditary predisposition to the main oral diseases diagnosis are presented. Application potentialities of DNA-markers for multiple testing in population are identified. Today very little information is available concerning Russia gene pool characteristics in genome polymorphism, DNA-markers-allelic gene variants, related to the caries predisposition. These characteristics are needed to solve the problems concerning dental diseases prophylaxis and treatment.

Adolescent↗

PubMed2000

Detection and analysis of gene expression during infection by in vivo expression technology.

Many limitations associated with the use of in vitro models for study of bacterial pathogenesis can be overcome by the use of technologies that detect pathogen gene expression during the course of infection within an intact animal. In vivo expression technology (IVET) accomplishes this with versatility: it has been developed with a variety of reporter systems which allow for either in vivo selection or ex vivo screening. Selectable gene fusion systems generally allow for the complementation of a bacterial metabolic defect that is lethal in vivo, or for antibiotic resistance during the course of in vivo antibiotic challenge. In contrast, the screenable gene fusion system uses a site-specific DNA recombinase that, when expressed in vivo, excises a selectable gene cassette from the bacterial chromosome. Loss of this cassette can then be either screened or selected for ex vivo. The recombinase-based IVET can be used to detect genes that are transcriptionally induced during infection, including those expressed transiently or at low levels and, in addition, can be used to monitor the spatial and temporal expression of specific genes during the course of infection.

Adaptation, Physiological↗

PubMed1988

Micropool procedure for routine donor antibody detection.

Microplate technology was combined with manual sample pooling techniques to determine if advantages associated with each method could he realized in a single test system. Fresh serum and plasma samples collected from routine blood donors and patient samples selected from frozen storage were screened for significant, unexpected antibodies. A total of 94 samples with known antibody specificities were selected for testing. Two micropool techniques, stream-micropool and mix-micropool, were compared to a Pooled-tube method. The stream-micropool method proved superior in overall detection of the antibodies (85%) and in detection of the macroscopically reactive antibodies (96%). Special formulas were used to calculate sensitivity, specificity and efficiency of each micropool method. The sensitivity of the stream-micropool method was 96 percent and that of the mix-micropool, 87 percent. For both methods, specificity and efficiency were >/=99 percent. In a separate study, there was no difference between the use of serum as opposed to plasma. Micropool methods offer a sensitive, easily mastered alternative to manual tube testing techniques for large hatch donor antibody detection.

Journal Article↗

PubMedDate not supplied

Emerging technologies in breast cancer detection.

While screening mammography is recognized as the most effective method for early detection of breast cancer, this modality has limitations that are the driving force behind efforts to refine existing mammography technologies and develop new ones offering improved detection of breast cancer. Full-field digital mammography (FFDM) systems use digital detectors to convert x-ray photons to digital signals for display on high-resolution monitors. These systems offer capabilities not provided by conventional film-screen mammography. Contrast-enhanced mammography utilizes the basic biological principle that aggressive cancers are associated with increased vascularity. Iodinated contrast agents--the same used in computed tomography (CT) examinations--are administered through an injection in a vein usually in the arm. They distribute throughout the blood system, and x-ray imaging shows increased contrast in areas where they concentrate. Tomosynthesis acquisition involves acquiring multiple images of a stationary compressed breast at different angles during a short scan. The individual images are then reconstructed into a 3D series of thin high-resolution slices. The slices can be displayed individually or in a dynamic ciné mode. The individual slices reduce tissue overlap and structure noise relative to standard 2D projection mammography, with a total dose comparable to that required for standard screening mammography. Initial efforts are underway to develop prototype systems to achieve high-resolution, whole-breast 3D ultrasound images that are co-registered with digital mammograms. This technology has the potential to improve specificity in breast imaging studies, particularly in dense breasts. Computer-aided detection (CAD) programs are intended to help radiologists identify suspicious lesions that may otherwise be overlooked. CAD software works similarly to a spellchecker and has the potential to increase the detection of cancer Magnetic resonanace imaging (MRI) is a generally accepted diagnostic procedure for a number of breast related indications. Its greatest strength is that it is very sensitive to tumors. If a suspected area does not exhibit contrast agent uptake, the probability that it is malignant is very small. Conversely, its specificity is poorer. If the area does show enhancement, it may or may not be a tumor. Further imaging or biopsy may be needed to resolve the question. Ultrasound holds promise as a method for detection of cancers in women with dense breast tissue, which is often problematic with conventional film-screen mammography. Ultrasound has also assumed an important role in breast imaging, as an adjunct to diagnostic mammography for biopsy guidance, palpable mass evaluation, and serial evaluation of benign masses.

Breast Neoplasms↗

PubMed1986

Review of methodology and technology available for the detection of extrasolar planetary systems.

Anyone undertaking an interstellar voyage might wish to be assured of the existence of a safe planetary harbor at the other end! Aside from the obvious interest of the participants in this Symposium, astronomers and astrophysicists are also eager to detect and study other planetary systems in order to better understand the formation of our own Solar System. Scientists involved in the search for extraterrestrial intelligence argue that planets suitable for the evolution of life may abound elsewhere within our own Milky Way Galaxy. On theoretical grounds, they are probably correct, but they lack any observational support. For in spite of decades of claimed astrometric detections of planetary companions and the recent exciting and tantalizing observations from the IRAS satellite and the IR speckle observations of Van Biesbroeck 8 and other cool stars, there is no unambiguous proof for the existence of another planetary system beyond our own. In this paper we review the various methods for detecting extrasolar planets and briefly describe the Earth and space based technology currently available and discuss the near-term plans to implement these different search techniques. In each case an attempt is made to identify the limiting source of systematic error inherent to the methodology and to assess the potential for technological improvements.

Astronomical Phenomena↗

PubMed1998

Electrospray ionization mass spectrometry for the study of non-covalent complexes: an emerging technology.

The detection of non-covalent complexes in the mass range 19,000-34,000 Da, using electrospray ionization mass spectrometry (ESI-MS), is reviewed. The examples discussed include (1) a protein-ligand interaction (ras-GDP), (2) an inhibitor-protein-ligand interaction (SCH 54292/SCH 54341-ras-GDP), (3) a protein-protein interaction (gamma-IFN homodimer) and (4) a protein-metal complex [HCV (1-181)-Zn]. In each case, the ESI-MS method is capable of releasing the intact non-covalent complex from its native solution state into the gas phase in the form of multiply-charge ions. The molecular masses of these complexes were determined with a mass accuracy of better than 0.01%, which is far superior to the traditional methods of sodium dodecyl sulfate polyacrylamide gel electrophoresis and gel permeation chromatography. The method provides the researcher with a quick, reliable and reproducible method for probing difficult biological problems. The key to success in the study of non-covalent complexes depends on careful understanding and manipulation of ESI source parameters and sample solution conditions; special care must be taken with the source orifice potential and the solution pH and organic co-solvents must be avoided. This paper also illustrates the usefulness of ESI-MS for addressing biological problems leading to the discovery of new therapeutics; the approach involves the rapid screening of potential drug candidates, such as weakly bound inhibitors.

Chelating Agents↗

PubMed1992

Detection of multiple cystic fibrosis mutations by reverse dot blot hybridization: a technology for carrier screening.

We describe the implementation of a modified version of the reverse dot blot hybridization technology to detect eight cystic fibrosis mutations. The method is simple, quick, reliable, inexpensive, and nonradioactive and utilizes the sensitivity of the polymerase chain reaction coupled with colored or chemiluminescent substrates for mutation detection. We have used this system in a clinical laboratory to identify the delta F508, G542X, G551D, R553X, 621 + 1G----T, W1282X, N1303K, and 1717G----A mutations. The technique is practical for genotyping individuals at many potential mutation sites, as in cystic fibrosis and beta-thalassemia, in which over 95 mutations can cause disease. This technology appears to be the method of choice for the widespread carrier screening of multiple cystic fibrosis mutations.

Base Sequence↗

PubMed2005

Detecting glaucoma with frequency-doubling technology perimetry: a comparison between N-30 and C-20 screening programs.

PURPOSE: To evaluate the ability of frequency-doubling technology (FDT) perimetry in detecting glaucoma with N-30 and C-20 screening programs. METHODS: Eighty eyes of 80 patients were enrolled (40 glaucomatous, 40 controls). Humphrey achromatic perimetry (standard automated perimetry, SAP) was considered as the "gold standard" for diagnosis. To assess whether N-30 screening program could detect more initial glaucomatous defects than C-20, glaucomatous patients included 20 cases with nasal step at SAP (pre-selected by medical chart inspection). Patients underwent two SAP examinations to confirm diagnosis; then two N-30 and two C-20 screening tests with frequency-doubling technology were performed in a randomized sequence. Finally, a frequency-doubling technology N-30 full-threshold examination was performed. Several criteria to define abnormality at frequency-doubling technology screening programs were evaluated. RESULTS: For both C-20 and N-30 screening programs, the best parameter to detect glaucoma was the presence of at least 1 point with P < 5% (sensitivity = 87.5% for both tests and specificity of 90% and 95% for C-20 and N-30, respectively). Both screening procedures obtained a lower sensitivity (75%) in patients with a nasal step, whereas frequency-doubling technology full-threshold program was able to detect the initial defects in all cases. CONCLUSIONS: N-30 and C-20 screening procedures obtained similar results in well-defined glaucoma patients in terms of sensitivity and specificity. In the presence of a standard automated perimetry nasal step, diagnostic ability with both frequency-doubling technology screening strategies decreased and one quarter of nasal steps went undetected.

Aged↗

PubMed2004

Label-free amplified bioaffinity detection using terahertz wave technology.

A new affinity biosensor based on pulsed terahertz (THz) wave technology has been used to monitor binding between biotin and avidin molecules. Amplified detection of avidin-biotin binding is obtained on supported membranes composed of biotin layers on quartz surface, which is modified with octadecanol. Agarose particles are conjugated with avidin and then applied to biotin, which is already bound to the octadecanol quartz surface, the biotin binds to the conjugate rapidly and causes an enhancement of the THz difference signal between biotin and biotin-avidin complexes by a factor greater than eight fold when compared to the same sample without agarose beads. The technique was able to detect less than 10.3 ng/cm2 avidin, thus, giving the THz system a detection capability of sub-thin solid films better than ellipsometry and reflectometry techniques. Further improvement is underway using highly refractive beads together with appropriate surface chemistry. This newly developed method is being saliently optimized for future application, including the detection of DNA hybridization and ligand-analyte affinity binding.

Affinity Labels↗

PubMed2004

Application of oligonucleotide array technology for the rapid detection of pathogenic bacteria of foodborne infections.

A rapid and accurate method for detection for common pathogenic bacteria in foodborne infections was established by using oligonucleotide array technology. Nylon membrane was used as the array support. A mutation region of the 23S rRNA gene was selected as the discrimination target from 14 species (genera) of bacteria causing foodborne infections and two unrelated bacterial species. A pair of universal primers was designed for PCR amplification of the 23S rRNA gene. Twenty-one species (genera)-specific oligonucleotide detection probes were synthesized and spotted onto the nylon membranes. The 23S rRNA gene amplification products of 14 species of pathogenic bacteria were hybridized to the oligonucleotide array. Hybridization results were analyzed with digoxigenin-linked enzyme reaction. Results indicated that nine species of pathogenic bacteria (Escherichia coli, Campylobacter jejuni, Shigella dysenteriae, Vibrio cholerae, Vibrio parahaemolyticus, Proteus vulgaris, Bacillus cereus, Listeria monocytogenes and Clostridium botulinum) showed high sensitivity and specificity for the oligonucleotide array. Two other species (Salmonella enterica and Yersinia enterocolitica) gave weak cross-reaction with E. coli, but the reaction did not affect their detection. After redesigning the probes, positive hybridization results were obtained with Staphylococcus aureus, but not with Clostridium perfringens and Streptococcus pyogenes. The oligonucleotide array can also be applied to samples collected in clinical settings of foodborne infections. The superiority of oligonucleotide array over other tests lies on its rapidity, accuracy and efficiency in the diagnosis, treatment and control of foodborne infections.

DNA, Bacterial↗

PubMed2004

Direct gene expression analysis.

The direct analysis of single biological molecules is getting increasingly important in basic as well as pharmaceutical research (e.g. for gene expression analysis). In particular single-molecule fluorescence detection provides exciting new opportunities to probe biochemical processes in unprecedented detail. Currently several academic and industrial research groups work on the development of single molecule detection based technologies in order to directly detect and analyze RNA and DNA molecules. As these developed methods are characterized as homogenous assays and obviate any amplification of the target or the signal, they provide clear advantages compared to methods like real-time PCR or DNA- arrays. In the following we describe a recently developed approach based on fluorescence correlation spectroscopy (FCS). This expression assay is based on gene-specific hybridization of two dye-labeled DNA probes to a selected target molecule (either DNA or RNA) in solution. The subsequent dual color cross-correlation analysis allows the quantification of the bio-molecule of interest in absolute numbers. Target concentrations of less than 10(-12) M can be easily monitored, covering the direct analysis of the expression levels of high, medium and low abundant genes.

Animals↗