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Results for “Detection”

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At least 487 records · Page 27Linked to original sources

PubMed1999

Comparison of three PCR techniques for detecting cytomegalovirus (CMV) DNA in serum, detection of early antigen fluorescent foci and culture for the diagnosis of CMV infection.

Three PCR assays were developed for detection of cytomegalovirus (CMV) DNA in serum and were evaluated with samples from organ transplant recipients. The Qiamp Blood Kit was efficient for extraction of DNA from sera. Single-round PCR of a 293-bp region of CMV DNA was sensitive and highly specific for CMV targets and was more sensitive than detection of early antigen fluorescent foci (DEAFF) testing or isolation of CMV from buffy coat by cell culture. The results of a significant proportion of buffy coat samples were not interpretable because of toxicity in conventional culture or DEAFF tests. A non-competitive quantitative PCR test and semi-quantitative PCR test for the detection of CMV DNA in serum yielded comparable results for samples taken serially from three bone marrow transplant recipients. Single-round PCR was superior to conventional techniques for the diagnosis of CMV infection, was simple to perform and was completed rapidly. The semi-quantitative technique has added advantages where quantification is important.

Adult↗

PubMed1979

Detection of 3-hydroxy fatty acids at picogram levels in biologic specimens. A chemical method for the detection of Neisseria gonorrhoeae?

A method for the detection of 3-hydroxy dodecanoic acid at low picogram levels is described. The procedure involves preparation of a heptafluorobutryl derivative of the butyl ester of the fatty acid and its detection by gas-liquid chromatography using an electron capture detector. The method was adapted for use with biological specimens. Potential of the method for screening for gonococcal infection is discussed. Limitations of the method are that about 105 Neisseria gonorrhoeae cells are required for detection and that interfering substances are a major problem working at maximum sensitivity of the electron capture detector necessitating complex purification procedures. The method eliminates the need to maintain the viability of cells in specimens, thus facilitating collection and transport of specimens.

Bacteriological Techniques↗

PubMed1991

Nondestructive detection of glutamate by 1H nuclear magnetic resonance spectroscopy in cortical brain slices from the guinea pig: evidence for changes in detectability during severe anoxic insults.

31P and 1H nuclear magnetic resonance spectroscopy (NMR) was used to study the metabolism of intact superfused cortical brain slices during normoxia and anoxia. Attention was focused on quantification of 1H NMR-detected glutamate by a water-suppressed spin-echo method, using N-acetyl aspartate as an internal concentration reference. To quantify the 1H NMR signals, the spin-spin relaxation times and saturation effects were estimated for given metabolites. In addition, absolute concentrations of metabolites were determined by biochemical methods from acid extracts of the preparations after NMR experiments. Under aerobic conditions, 1H NMR detected 79% of the glutamate determined biochemically from the brain slice extracts. During anoxia in the absence of glucose when a severe energetic failure was evident, both 1H NMR and biochemical assays gave closely matching levels for glutamate. We conclude that in the brain cortex 21% of glutamate is located in an intracellular compartment in which this amino acid does not contribute to the 1H NMR signal. However, during severe anoxia an intracellular reorganisation occurs increasing the detectability of this amino acid neurotransmitter by NMR.

Animals↗

PubMedDate not supplied

Detection of the Dinozoans Pfiesteria piscicida and P. shumwayae: a review of detection methods and geographic distribution.

Molecular methods, including conventional PCR, real-time PCR, denaturing gradient gel electrophoresis, fluorescent fragment detection PCR, and fluorescent in situ hybridization, have all been developed for use in identifying and studying the distribution of the toxic dinoflagellates Pfiesteria piscicida and P. shumwayae. Application of the methods has demonstrated a worldwide distribution of both species and provided insight into their environmental tolerance range and temporal changes in distribution. Genetic variability among geographic locations generally appears low in rDNA genes, and detection of the organisms in ballast water is consistent with rapid dispersal or high gene flow among populations, but additional sequence data are needed to verify this hypothesis. The rapid development and application of these tools serves as a model for study of other microbial taxa and provides a basis for future development of tools that can simultaneously detect multiple targets.

Animals↗

PubMed1998

Telomerase activity detected in pancreatic juice 19 months before a tumor is detected in a patient with pancreatic cancer.

We report a patient with pancreatic cancer in whom telomerase activity had been detected in the pancreatic juice 19 months before he was diagnosed as having pancreatic cancer. A 61-yr-old alcoholic man complaining of epigastric and back pain was diagnosed as having groove pancreatitis based on the presence of inflammation in the pancreatic head and its extension to the duodenal mucosa with an associated elevated serum amylase level. All imaging modalities showed no sign of a tumor. However, high telomerase activity was detected in the pancreatic juice collected during endoscopic retrograde pancreatography. His symptoms subsided due to abstinence from alcohol. A tumor, however, was recognized on computed tomography 19 months later, at which time the patient immediately underwent a pylorus-preserving pancreaticoduodenectomy. The carcinoma was located mainly in the Santorini duct region. High telomerase activity in the pancreatic juice may precede clinical detection of pancreatic cancer and thus could be a useful early diagnostic marker for pancreatic cancer.

Biomarkers, Tumor↗

PubMed2006

Binaural detection with narrowband and wideband reproducible noise maskers. III. Monaural and diotic detection and model results.

A single-interval, yes-no, tone-in-noise detection experiment was conducted to measure the proportion of "tone present" responses to each of 25 reproducible noise-alone and tone-plus-noise waveforms under narrowband (100 Hz), wideband (2900 Hz), monotic, and diotic stimulus conditions. Proportions of "tone present" responses (estimates of the probabilities of hits and false alarms) were correlated across masker bandwidths and across monotic and diotic conditions. Two categories of models were considered; one based on stimulus energy or neural counts, and another based on temporal structure of the stimulus envelope or neural patterns. Both categories gave significant correlation between decision variables and data. A model based on a weighted combination of energy in multiple critical bands performed best, predicting up to 90% of the variance in the reproducible-noise data. However, since energy-based models are unable to successfully explain detection under a roving-level paradigm without substantial modification, it is argued that other variations of detection models must be considered for future study. Temporal models are resistant to changes in threshold under roving-level conditions, but explained at most only 67% of the variance in the reproducible-noise data.

Adult↗

PubMed2003

Agrobacterium bioassay strain for ultrasensitive detection of N-acylhomoserine lactone-type quorum-sensing molecules: detection of autoinducers in Mesorhizobium huakuii.

An ultrasensitive bioassay system for the detection of N-acylhomoserine lactones (AHLs) was constructed in Agrobacterium tumefaciens by using the T7 expression system to overproduce the AHL receptor TraR. This strain detected many diverse AHLs, some at extremely low concentrations. We used this strain to detect for the first time AHLs made by Mesorhizobium huakuii, which symbiotically fixes nitrogen in association with the legume Astragalus sinicus, a source of green manure throughout eastern Asia.

4-Butyrolactone↗

PubMed1993

Rapid detection of Legionella species in bronchoalveolar lavage fluids with the EnviroAmp Legionella PCR amplification and detection kit.

A molecular assay based on a rapid DNA extraction protocol and the EnviroAmp Legionella Kits was used to detect Legionella species in bronchoalveolar fluid specimens. All Legionella strains isolated from tap water in hospitals could be detected distinctly. Both sensitivity and specificity were tested. In a prospective study, bronchoalveolar lavage fluids obtained from patients with atypical pneumonia were investigated. Three positive samples were detected with the molecular techniques and were subsequently confirmed by culture. Application of the system described may lead to safe and early diagnosis of Legionnaires' disease in patients with atypical pneumonia.

Bacteriological Techniques↗

PubMed1994

Detection of antibodies to human immunodeficiency virus in vaginal secretions by immunoglobulin G antibody capture enzyme-linked immunosorbent assay: application to detection of seminal antibodies after sexual intercourse.

In order to evaluate a commercial immunoglobulin G (IgG) antibody capture enzyme-linked immunoassay (ELISA) (Wellcozyme HIV1 + 2 Gacelisa; Murex Diagnostics Limited, Dartford, United Kingdom) for the detection of antibodies to human immunodeficiency virus (HIV) in vaginal secretion samples (VS) from HIV-seropositive and -seronegative women, serum samples (S) and VS were obtained from 129 African women living in the Central African Republic, a country of high HIV prevalence. Sera were tested for HIV by routine second-generation ELISA with confirmatory Western blot (immunoblot) (WB). By the Gacelisa IgG immuno-capture assay, 45 VS were positive and 84 were negative, whereas by WB, 44 VS were confirmed positive and 85 were confirmed negative. Considering WB as a reference, the IgG immunocapture assay in VS was 97.7% sensitive (43 of 44 positive samples) and 97.6% specific (83 of 85 negative samples). Of 42 HIV-seropositive women, 41 (97.6%) had S and VS that both were HIV positive (S+ VS+), and of 87 HIV-seronegative women, 83 (95.4%) had S and VS that both were HIV negative (S- VS-). Five women had discordant results for S and VS. One (S+ VS-) possibly had a false-negative VS result. Two (S- VS+) had similar indeterminate patterns for S and VS in WB. Two (S- VS+) had a typical HIV-positive pattern on WB of VS, whereas S results in WB were indeterminate in one case and negative in the other case; for both women, detection of prostatic acid-phosphatase was positive in VS, strongly suggesting recent sexual intercourse with an HIV-positive man. Because all HIV-infected men have detectable IgG antibodies to HIV in the seminal fluid, an HIV-seronegative rape victim with HIV-positive VS (S- VS+) should receive short-term antiviral therapy to prevent possible HIV transmission.

Adolescent↗

PubMed1996

Rapid reverse transcription-PCR detection of hepatitis C virus RNA in serum by using the TaqMan fluorogenic detection system.

We describe the application of a new fluorogenic probe-based PCR assay (TaqMan; Perkin Elmer Corp./Applied Biosystems, Foster City, Calif.) for the detection of hepatitis C virus RNA in serum and plasma. This assay allows for the direct direction of specific PCR products within minutes of completion of the PCR by monitoring the increase in fluorescence of a dye-labeled oligonucleotide probe. We evaluated this assay by comparing the results obtained by nested PCR with those obtained by TaqMan PCR. Test samples included two separate dilutions series of plasma samples from experimentally infected chimpanzees and a panel of 48 serum specimens from patients with community-acquired hepatitis C virus. The quantity of HCV RNA in each chimpanzee plasma sample was determined by using branched DNA (bDNA) signal amplification assay (Quantiplex HCV RNA assay; Chiron Corp., Emeryville, Calif.). Both PCR assays demonstrated similar levels of detection and could reliably detect 13 bDNA genome equivalents per sample. We found an overall concordance of 88% between results of two PCR assays with the community-acquired panel, which resolved to 100% when discrepant samples were retested by nested PCR. TaqMan compared favorably with nested PCR with key advantages of speed, increased throughput, and decreased opportunity for false-positive results because of elimination of second-round amplification.

Animals↗

PubMed1996

Interlaboratory comparison of sequence-specific PCR and ligase detection reaction to detect a human immunodeficiency virus type 1 drug resistance mutation. The AIDS Clinical Trials Group Virology Committee Drug Resistance Working Group.

Sequence-specific PCR was used in six laboratories and a ligase detection reaction was used in one laboratory to detect the zidovudine-resistance mutation at codon 215 of human immunodeficiency virus type 1 (HIV-1) reverse transcriptase DNA. The genotypes of 27 different clinical samples, including cultured HIV-1 isolates, peripheral blood mononuclear cells, and plasma, were correctly identified by 140 of 154 (91%) assays. The sensitivity for detecting a mutation was 96% for HIV-1 reverse transcriptase DNA clone mixtures containing 30% mutant DNA and 62% for mixtures containing 6% mutant DNA.

Antiviral Agents↗

PubMed2000

Rapid detection of contagious caprine pleuropneumonia using a Mycoplasma capricolum subsp. capripneumoniae capsular polysaccharide-specific antigen detection latex agglutination test.

Latex microspheres (diameter, 8 microm) were coated with anti-Mycoplasma capricolum subsp. capripneumoniae polyclonal immunoglobulin G (IgG) antiserum (anti-F38 biotype). The coated microspheres, when used in a latex agglutination test (LAT), detected M. capricolum subsp. capripneumoniae antigen in the serum of goats with contagious caprine pleuropneumoniae (CCPP). Beads also agglutinated strongly in the presence of purified M. capricolum subsp. capripneumoniae capsular polysaccharide (CPS). Preabsorption of CPS-specific antibodies prior to coating of the beads removed agglutinating activity in the presence of M. capricolum subsp. capripneumoniae, strongly suggesting that CPS is the likely soluble antigen recognized by the test. In addition, the specificity of the LAT exactly mirrored that of an M. capricolum subsp. capripneumoniae CPS-specific monoclonal antibody (WM25): of the 8 other mycoplasma species tested, agglutination was observed only with bovine serogroup 7. The LAT detected all 11 strains of M. capricolum subsp. capripneumoniae examined in this study, with a sensitivity level of 2 ng of CPS, or the equivalent of 1.7 x 10(4) CFU, in a reaction volume of 0.03 ml of serum. With field sera from goats with CCPP, the results of the LAT exhibited a 67% correlation with the results of the currently used complement fixation test (CFT), with the main discrepancy in diagnosis resulting from the increased sensitivity of the LAT compared to that of CFT. This antigen-detection LAT should prove particularly useful in identifying animals in the earliest stages of CCPP and combines sensitivity and low cost with ease of application in the field, without the need for any specialist training or equipment.

Animals↗

PubMed2002

Rapid detection of herpes simplex virus DNA in genital ulcers by real-time PCR using SYBR green I dye as the detection signal.

We have evaluated a real-time PCR procedure based on the LightCycler technology for rapid detection of herpes simplex virus (HSV) in genital lesions. Two sets of primers, corresponding to the thymidine kinase and DNA polymerase regions, were used for the amplification reactions in separate capillaries containing the SYBR Green I dye as detection signal. In 28 of 118 samples (24%), HSV was isolated by conventional cell culture. All cell culture-positive samples were also positive by real-time PCR. Six additional cell culture-negative samples were positive by PCR with both sets of primers. Total processing time was less than 3 h. Real-time PCR using SYBR Green I as detection signal is a sensitive procedure for the rapid diagnosis of HSV in genital lesions.

Benzothiazoles↗

PubMed1997

Optimization of nuclear transcript detection by FISH and combination with fluorescence immunocytochemical detection of transcription factors.

Detection of specific nuclear transcripts by fluorescence in situ hybridization (FISH) has constituted a major breakthrough in the study of the organization of transcription in the cell nucleus. Using the model of heat shock genes, we present an optimized procedure for nuclear transcripts that provides high efficiency for RNA detection and good preservation of cell morphology and nuclear texture. Using this procedure, we designed an original high-efficiency methodology combining FISH and fluorescence immunocytochemistry (FICC), which is used here for the simultaneous detection of heat-shock protein (hsp) nuclear transcripts and the specific heat-shock transcription factor 1 (HSF1). We show that the nuclear accumulation sites of HSF1 in heat-shocked cells do not correspond to the sites of transcription of the hsp70 gene.

Cell Nucleus↗

PubMedDate not supplied

A signal-detection experiment measuring the effect of computer-aided detection on radiologists' performance.

PURPOSE: To evaluate how the specificity and sensitivity of computer-aided detection (CADe) algorithm outputs affected radiologists' diagnostic performances, the authors studied the effects of 25 simulated CADe algorithms with various sensitivities and specificities (from 60% to 100%). METHODS: Six novice radiologists read 200 images that were produced by computer and randomly displayed on CRT, and their detection performances were evaluated with receiver operating characteristic analysis. RESULTS: There were significant differences in performance among CADe types (p < 0.001). DISCUSSION AND CONCLUSION: The overall accuracy of CADe outputs is the most significant factor affecting radiologists' performances in detection and interpretation of images. There is an approximately linear relationship between the sensitivity (specificity) of the CADe output and the reader's sensitivity (specificity), and the slope of reader sensitivity (specificity) as a linear function of CADe sensitivity (specificity) can be considered to be a positive number less than unity.

Algorithms↗

PubMed1990

Detection of calcitonin-encoding mRNA by radioactive and non-radioactive in situ hybridization: improved colorimetric detection and cellular localization of mRNA in thyroid sections.

The localization of mRNA encoding calcitonin was studied by in situ hybridization using 35S-labeled RNA probes and biotin-labeled DNA probes. Radiolabeled probes were detected by autoradiography and biotin-labeled probes by streptavidin-biotin-peroxidase. To intensify the colorimetric signal, the indirect avidin-biotin complex (ABC) method was performed. However, the results were often variable. To improve the sensitivity, the peroxidase reaction signal was enhanced with a gold-silver deposit intensification reaction. To shorten the incubation times and to enhance the colorimetric reaction, several reaction steps were performed in a microwave oven. The localization of calcitonin mRNA in thyroid tissue, as detected with in situ hybridization, was confirmed by immunohistochemical localization of the calcitonin polypeptide. The results of in situ hybridization using biotinylated probes were compared to in situ hybridization using radioactive probes. Our data show that the results of in situ hybridization applied on frozen and paraffin-embedded sections using biotinylated DNA probes, detected with an indirect streptavidin-biotin-peroxidase reaction and intensified by silver-gold enhancement, were comparable to those obtained with radioactive probes. The localization of calcitonin encoding mRNA was in agreement with the localization of the calcitonin polypeptide.

Affinity Labels↗

PubMed2003

Bioelectronic DNA detection of human papillomaviruses using eSensor: a model system for detection of multiple pathogens.

BACKGROUND: We used human papillomaviruses (HPV) as a model system to evaluate the utility of a nucleic acid, hybridization-based bioelectronic DNA detection platform (eSensor) in identifying multiple pathogens. METHODS: Two chips were spotted with capture probes consisting of DNA oligonucleotide sequences specific for HPV types. Electrically conductive signal probes were synthesized to be complementary to a distinct region of the amplified HPV target DNA. A portion of the HPV L1 region that was amplified by using consensus primers served as target DNA. The amplified target was mixed with a cocktail of signal probes and added to a cartridge containing a DNA chip to allow for hybridization with complementary capture probes. RESULTS: Two bioelectric chips were designed and successfully detected 86% of the HPV types contained in clinical samples. CONCLUSIONS: This model system demonstrates the potential of the eSensor platform for rapid and integrated detection of multiple pathogens.

Biosensing Techniques↗

PubMed2004

Improved small volume lung cancer detection with computer-aided detection: database characteristics and imaging of response to breast cancer risk reduction strategies.

Computer-aided detection (CAD) and diagnosis (CADx) of in vivo imaging studies are important tools based on bioinformatics. Currently, there are two diseases for which the United States Food and Drug Administration (FDA) has given premarket approval (PMA): the detection of signs consistent with lung cancer on chest radiographs and breast cancer on mammograms. There are systems for other diseases and other types of images under development; however, this process depends on the availability of an accurate database. The author helped in the development of the databases for such systems and management of the clinical trial that resulted in the FDA-PMA of the system that detects findings consistent with lung cancer. The characteristics of the database used will be described. Further, a woman's risk of developing breast cancer differs from those of other women. Risk can be high, average, or low. There are now pharmaceuticals that decrease the risk that women, as a group, will develop breast cancer and it has been suggested that dietary changes could have similar effects. The pharmaceutical agents, though, have some associated side effects, and it is clinically important to determine whether these agents have decreased an individual woman's risk of breast cancer. In vivo imaging biomarkers of risk and successful risk reduction are therefore sought, but the information on possible in vivo imaging biomarkers is less mature than activities in CAD. Bioinformatics will be an important contributor to this in vivo imaging biomarker development.

Breast Neoplasms↗