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PubMed1988

The application of a photon-counting camera in very sensitive, bioluminescence-enhanced detection systems for protein blotting. Ultrasensitive detection systems for protein blotting and DNA hybridization, II.

A relatively simple, very sensitive bioluminescence-enhanced detection system for protein blots was described recently. This method utilizes antibodies conjugated with alkaline phosphatase. Alkaline phosphatase releases D-luciferin (Photinus pyralis) from D-luciferin-O-phosphate. Liberated D-luciferin reacts with luciferase, ATP and oxygen with light emission. The light produced is measured with a very sensitive photon counting camera (Argus 100), permitting visualization and localization of the alkaline phosphatase-conjugated antibodies on nitrocellulose sheets. Under non-optimized conditions the limit of detection is at present 5 to 500 fg of protein (rabbit immunoglobulin G), corresponding to 30 to 3 amol. The method is therefore 10(5) times more sensitive than other used at present.

DNA↗

PubMed1987

[A method for detecting protein-protein interactions. Detection of proteins with the molecular weight of approximately 37 kD binding with tryptophanyl-tRNA-synthetase].

A procedure for detecting protein-protein interactions is proposed. It is based on blotting of electrophoretically separated protein mixtures followed by detection of the proteins interacting with a given 125I-labelled protein used as a probe. Application of this approach to lysates of cultured mammalian cells enabled us to reveal a unique 37 kDa polypeptide interacting with 125I-labelled bovine tryptophanyl-tRNA synthetase (EC 6.1.1.2).

Amino Acyl-tRNA Synthetases↗

PubMed1987

Detection characteristics of a commercially available sulfite detection test (SULFITEST): problems with decreased sensitivity and false negative reactions.

Recently, a product (SULFITEST; Center Laboratories) has become available for detecting the presence of sulfiting agents in foods. Testing with SULFITEST by the indirect method (ie, holding the test strip above the food product) or the direct method (ie, touching the test strip directly on the food) was associated with false negative results in five out of nine acidic sulfite-containing foods. Quantitative studies also confirmed that low pH conditions and/or the presence of ascorbic acid caused SULFITEST results by the direct method to significantly underestimate known concentrations of sulfites. Dependence on this sulfite detection strip may lead to unrecognized ingestion of sulfiting agents, especially in acidic and/or ascorbic acid-containing foods.

Ascorbic Acid↗

PubMed1995

Breast cancer early detection: differences between African American and white women's health beliefs and detection practices.

PURPOSE/OBJECTIVES: To identify differences in African American and white women's health beliefs and practices regarding early detection of breast cancer. DESIGN AND SETTING: Descriptive survey of educators employed by one public school system in one southern state. SAMPLE: One hundred seventeen African American and 157 white female professional educators. METHODS: Subjects completed a survey questionnaire consisting of investigator-developed items and an adapted version of Champion's Health Belief Model Scales. MAIN OUTCOME MEASURES: Reported frequency of use of mammography, clinical breast examination (CBE), and breast self-examination (BSE); health beliefs about these procedures. FINDINGS: No significant difference in frequency of use of mammography and CBE was found between the two groups. The difference for BSE frequency approached significance (p = 0.058); African American women had performed BSE significantly more times (p = 0.028) than white women during the preceding 12 months. White women had a significantly higher mean score (p = 0.002) for barriers to mammography. The difference between the two groups for barriers to CBE and control with CBE reached the 0.05 level of significance; in both cases, white women had the higher mean score. No significant difference was found in mean scores for beliefs about BSE. CONCLUSIONS: The contribution of health beliefs about breast cancer, mammography, CBE, and BSE to frequency of use of these procedures by race remains unclear. IMPLICATIONS: Efforts to inform women of the need to adopt an early breast cancer detection program should continue. Additional studies are needed to validate present study findings and to expand the knowledge base for healthcare providers.

Adult↗

PubMed1995

Detection of cyclin messenger RNAs by nonradioactive ribonuclease protection assay: a comparison of four detection methods.

Stable, nonradioactive riboprobes were used in ribonuclease protection assays to monitor the changes in cyclin mRNA expression during cell cycle progression in human mammary epithelial cells. Probes labeled with biotin demonstrated sufficient sensitivity (comparable to 32P) to detect these low-abundance mRNAs and thus offer a safe and easy alternative to traditional radioactive assays. Three detection systems based on chemiluminescence generated by horseradish peroxidase or alkaline phosphatase were compared for sensitivity, background and ease of use.

Bacterial Proteins↗

PubMed1996

Heat-mediated immune complex dissociation and enzyme-linked immunosorbent assay signal amplification render p24 antigen detection in plasma as sensitive as HIV-1 RNA detection by polymerase chain reaction.

OBJECTIVE: To compare heat denaturation and acidification as immune complex dissociation (ICD) methods in adult HIV-1 infection and to increase the sensitivity by a signal-amplification-boosted HIV-1 p24 antigen enzyme-linked immunosorbent assay (ELISA). DESIGN: Prospective and retrospective blinded study of paired serum and plasma samples from 245 patients (112 of class A, 66 of B, 67 of C of the Centers for Disease Control and Prevention 1993 classification). METHODS: Plasma and sera were prospectively tested for antigen by ELISA using native, acidified, or heat-denatured material. Retrospective tests included batch analysis of heat-denatured samples for antigen by the signal-amplification-boosted ELISA and for viral RNA. RESULTS: With serum, native antigen was reactive in 26.5%. Acidification increased the rate to 53.1% (P < or = 0.0001), but was inefficient at a CD4+ count > or = 500 x 10(6)/l. Heat denaturation further elevated the rate to 67.8% (P < or = 0.0007) and the use of plasma to 78.0% (P < or = 0.008). The boosted ELISA, performed with plasma samples diluted 1 :6, which eliminated the problem of heat-induced sample coagulation, was confirmed positive in 89.5% of serum and 97.8% of plasma samples. RNA was detected in 95.7%. CONCLUSION: Heat-mediated ICD combined with a signal-amplification-boosted ELISA detects HIV-1 expression as sensitively as a polymerase chain reaction kit for viral RNA, but at only a fraction of the cost. The procedure uses a 50 microliters plasma sample and should be fully automatable.

Adult↗

PubMed2005

Detection and management of associated atherothrombotic locations in patients with a recent atherothrombotic ischemic stroke: results of the DETECT survey.

BACKGROUND: Cerebral infarction (CI), myocardial infarction, peripheral artery disease (PAD) and aortic atheroma are the main clinical manifestations of atherothrombosis. Long-term prevention after CI of atherothrombotic origin may require preventive measures at other sites, such as specific drug therapies, surgery, or angioplasty. Therefore the detection of other locations is potentially important. OBJECTIVES: The primary objective was to describe the other locations of atherothrombosis in patients hospitalized for a recent cerebral infarct of atherothrombotic origin. Secondary objectives were to describe their vascular risk factor profiles, and their management before and after the cerebral event. METHOD: This prospective, observational, multicenter survey was conducted in France between September 2003 and July 2004, mainly in neurological departments and stroke units. RESULTS: 753 patients were included (74% men; mean age 69.3 years). Previous coronary events had occurred in 119 (16%). Previous stroke or transient ischemic attacks had occurred in 233 (31%). PAD was already known in 109 (15%). A search for other atherothrombotic locations was positive in 216 patients (29%). The minimum prevalence for any associated atherothrombotic location (either present before or identified during hospitalization) was 47.5% for any location, 33.7% for coronary artery disease, 16.6% for aortic atheroma, and 22.7% for PAD. CONCLUSION: Fifty percent of the patients with recent atherothrombotic CI have other locations of atherothrombosis. For this reason, a systematic search for these other locations is recommended because of the possible therapeutic consequences. However, the question of the most appropriate period for this search after the cerebral event remains unsettled.

Adult↗

PubMed2004

A detection theory account of change detection.

Previous studies have suggested that visual short-term memory (VSTM) has a storage limit of approximately four items. However, the type of high-threshold (HT) model used to derive this estimate is based on a number of assumptions that have been criticized in other experimental paradigms (e.g., visual search). Here we report findings from nine experiments in which VSTM for color, spatial frequency, and orientation was modeled using a signal detection theory (SDT) approach. In Experiments 1-6, two arrays composed of multiple stimulus elements were presented for 100 ms with a 1500 ms ISI. Observers were asked to report in a yes/no fashion whether there was any difference between the first and second arrays, and to rate their confidence in their response on a 1-4 scale. In Experiments 1-3, only one stimulus element difference could occur (T = 1) while set size was varied. In Experiments 4-6, set size was fixed while the number of stimuli that might change was varied (T = 1, 2, 3, and 4). Three general models were tested against the receiver operating characteristics generated by the six experiments. In addition to the HT model, two SDT models were tried: one assuming summation of signals prior to a decision, the other using a max rule. In Experiments 7-9, observers were asked to directly report the relevant feature attribute of a stimulus presented 1500 ms previously, from an array of varying set size. Overall, the results suggest that observers encode stimuli independently and in parallel, and that performance is limited by internal noise, which is a function of set size.

Adolescent↗

PubMed2000

The aneurysm detection and management study screening program: validation cohort and final results. Aneurysm Detection and Management Veterans Affairs Cooperative Study Investigators.

BACKGROUND: We previously reported the prevalence and associations of abdominal aortic aneurysm (AAA) in 73451 veterans aged 50 to 79 years who underwent ultrasound screening. OBJECTIVE: To understand the prevalence of and principal positive and negative risk factors for AAA, and to assess reproducibility of our previous findings. METHODS: In the new cohort of veterans undergoing screening, 52 745 subjects aged 50 to 79 without history of AAA underwent successful ultrasound screening for AAA, after completing a questionnaire on demographics and potential risk factors. RESULTS: We detected AAA of 4.0 cm or larger in 613 participants (1.2%; compared with 1.4% in the earlier cohort). The direction and magnitude of the important associations reported in the first cohort were confirmed. Respective odds ratios for the major associations with AAA for the second and for the combined cohorts were as follows: 1.81 and 1.71 for age (per 7 years), 0.12 and 0. 18 for female sex, 0.59 and 0.53 for black race, 1.94 and 1.94 for family history of AAA, 4.45 and 5.07 for smoking, 0.50 and 0.52 for diabetes, and 1.60 and 1.66 for atherosclerotic diseases. The excess prevalence associated with smoking accounted for 75% of all AAAs of 4.0 cm or larger in the total population of 126 196. Associations for AAA of 3.0 to 3.9 cm were similar but tended to be somewhat weaker. CONCLUSIONS: Our findings confirm our previous cohort findings. Age, smoking, family history of AAA, and atherosclerotic diseases remained the principal positive associations with AAA, and female sex, diabetes, and black race remained the principal negative associations.

Aged↗

PubMed2005

Effect of using 2 throat swabs vs 1 throat swab on detection of group A streptococcus by a rapid antigen detection test.

OBJECTIVE: To assess the effect of using 2 throat swabs vs 1 on rapid detection of group A streptococcus by the STREP A OIA MAX (hereafter, OIA MAX) test. METHODS: Children aged 5 to 18 years with acute pharyngitis were randomized to 1 of 2 study groups. In group 1, one throat swab was obtained, streaked first on sheep blood agar, and then used for OIA MAX testing. In group 2, two throat swabs were obtained simultaneously. One swab was streaked first on sheep blood agar and then joined with the other swab for OIA MAX testing. In both groups, the pledgets in the collection-transport tube were incubated in Todd-Hewitt broth. A positive group A streptococcus culture either by sheep blood agar or Todd-Hewitt broth was confirmed by a latex agglutination test. RESULTS: Three hundred sixty-three patients were enrolled, 177 in group 1 and 186 in group 2. Cultures were positive for group A streptococcus in 154 (42.4%) of 363 patients. The sensitivity and specificity of OIA MAX testing were 94.7% and 100.0%, respectively, in group 1, and 92.4% and 96.3%, respectively, in group 2. There was no statistical difference between the sensitivity, the specificity, and the predictive values of the OIA MAX test performed with 1 swab compared with those performed with 2 swabs (P>.10). There was no association between OIA MAX test sensitivity and the severity of pharyngitis as measured by the modified Centor criterion (history of fever, absence of cough, presence of pharyngeal or tonsillar exudates, and presence of cervical lymphadenopathy) scores. CONCLUSIONS: The OIA MAX test yielded comparable sensitivity and specificity in both study groups. The use of 2 throat swabs instead of 1 swab did not increase the sensitivity of the OIA MAX test. The performance of the OIA MAX test did not depend on the severity of pharyngitis.

Adolescent↗

PubMed1979

Five-year findings of the hypertension detection and follow-up program. II. Mortality by race-sex and age. Hypertension Detection and Follow-up Program Cooperative Group.

Data are reported for four race-sex and three age subgroups of the Hypertension Detection and Follow-up Program (HDFP). Throughout the HDFP trial, for black men, black women, white men, and white women and for persons aged 30 to 49, 50 to 59, and 60 to 69 years at entry, control of blood pressure was consistently better for Stepped Care (SC) than Referred Care (RC) participants. This difference in degree of control was least for white women; it was less for whites than for blacks of the same sex. For white men, black men, and black women and for age subgroups 50 to 59 and 60 to 69 years, five-year all-cause death rates were substantially lower--by 15% to 28%--for the SC subgroups compared to the RC subgroups.

Adult↗

PubMed1988

Bleomycin-detectable iron and phenanthroline-detectable copper in the cerebrospinal fluid of patients with neuronal ceroid-lipofuscinoses.

The neuronal ceroid-lipofuscinoses (NCLs) are a group of recessively inherited neurodegenerative lysosomal storage diseases, the pathogenesis of which is unknown. In the present study, we have measured iron and cooper in cerebrospinal fluids (CSF) using methods that detect these metals in a "loosely bound" form, complexable to the chelators bleomycin and 1,10-phenanthroline. We studied 25 children with NCL, 21 children with encephalopathy of some other type, and 5 control children without neurological complications. The CSF concentrations of loosely bound iron at neutral pH values and of loosely bound copper did not correlate with the clinical diagnosis of the patients, nor did they parallel degenerative symptoms in NCL, such as mental impairment, visual loss, motor handicap, and epilepsy. However, the concentrations of loosely bound iron and copper increased significantly with the age of the patient; this is a novel finding and may represent increasing tissue destruction with age. Our present findings do not support a major role for primary iron toxicity in the development of neuronal degeneration. To investigate any secondary pathological role for malplaced transition metals, further research is required.

Biomarkers↗

PubMedDate not supplied

Photochemiluminescent detection of antiradical activity. VII. Comparison with a modified method of thermo-initiated free radical generation with chemiluminescent detection.

The method of photosensitized chemiluminescence (PCL) allows the quantification of water- and lipid-soluble antioxidants and activity of superoxide dismutase (SOD) in the same measuring system. However, it needs a special device, which we have described in a previous paper in this series. Another method suitable for the assay of water- and lipid-soluble antioxidants is the thermo-initiated decay of azo-compounds combined with the measurement of O2 consumption (Niki, 1985; Wayner et al., 1985). Its long duration and the complicated measuring procedure is not acceptable for routine medical applications. We show that a modification using CL detection of free radicals with luminol, has results comparable with PCL for the determination of non-enzymic water- and lipid-soluble antioxidants, SOD activity and oxidative modification of proteins. In contrast to PCL, it is possible to use any luminometer with a heatable measuring cell and to investigate coloured samples. While the new method has an overall higher sensitivity and is scalable to microtitre plates, PCL measurements can be made at different pH. The advantages and analytical information content of certain components of the integral antioxidative capacity of blood plasma are discussed in comparison with other methods.

Ascorbic Acid↗

PubMed1998

Fast detection of a (CA)18 microsatellite repeat in the IgE receptor gene by capillary electrophoresis with laser-induced fluorescence detection.

The optimum separation conditions of polymerase chain reaction (PCR) products have been found for high-speed capillary electrophoresis (CE) with laser-induced fluorescence (LIF) detection. DNA fragments obtained after PCR amplification of the region covering the (CA)18 microsatellite repeat in nitron 5 of the gene for FcERIbeta, a high affinity glycoprotein receptor for IgE, located on chromosome 11 (11q13), were analyzed with the aim of investigating the repeat polymorphism. The results of polyacrylamide slab gel electrophoresis (PAGE), agarose gel electrophoresis, CE with absorbance detector and CE with LIF are compared. The CE with LIF proved to shorten analysis time by a factor of 100 when compared to slab gel electrophoresis. CE-LIF utilizes a short capillary with an effective length of 6.3 cm and electric field strength from 100 to 550 V/cm. The respective PCR products of sizes from 116 to 210 base pairs (bp) were analyzed in 3 min.

Base Sequence↗

PubMed2005

Discontinuous electrolyte systems for improved detection of biologically active amines and acids by capillary electrophoresis with laser-induced native fluorescence detection.

On-line concentration and separation of biologically active amines and acids by capillary electrophoresis (CE) in conjunction with laser-induced fluorescence using an Nd:YAG laser at 266 nm under discontinuous conditions is presented. The suitable conditions for simultaneous analysis of amines and acids were: samples were prepared in a solution (pH* 3.1) consisting of 10 mM citric acid, 89% acetonitrile (ACN), and water; a capillary was filled with 1.5 M Tris-borate (TB) buffer (pH 10.0); and the anodic vial contained PTG10 buffer (pH* 9.0) that consists of 50 mM propanoic acid, Tris, 10% glycerol, and water. After injecting a large-volume sample, amines and acids were separately stacked at the front (cathodic side) and back (anodic side) of the acidic sample zone, mainly because of changes in their electrophoretic mobilities as a result of changes in pH, viscosity, and electric field when high voltage was applied. When the sample was injected at 15 kV for 360 s, the concentration limits of detection (LODs) for 5-hydroxytryptamine (5-HT) and 5-hydroxyindole-3-acetic acid (5-HIAA) were 0.27 and 0.31 nM, respectively, which are about 400- and 800-fold sensitivity improvements when compared to those injected at 1 kV for 10 s. For the analysis of amines, samples were prepared in 100 mM citric acid (pH* 1.8) containing 89% ACN and both the capillary and anodic vial were filled with 400 mM PTG20 (propanoic acid, Tris, 20% glycerol, and water) at pH* 4.5. Using a large injection volume (15 kV for 360 s), we achieved concentration LODs of 17 pM and 0.3 nM for tryptamine and epinephrine, which are about 5200- and 14,000-fold sensitivity improvements, respectively, in comparison with those injected at 1 kV for 10 s. The features of simplicity (no sample pretreatment), rapidity (12 min), and sensitivity for identification of amines and acids of interest in urine samples show diagnostic potential of the two approaches developed in this study.

Acids↗

PubMed2005

In vivo detection of iron and neuromelanin by transcranial sonography: a new approach for early detection of substantia nigra damage.

Early diagnosis of Parkinson's disease (PD) in nonsymptomatic patients is a key issue. An increased echogenicity of the substantia nigra (SN) was found previously in Parkinsonian patients and in a low percentage of healthy adults. These nonsymptomatic subjects also showed a reduced 18F-dopa uptake in striatum, suggesting a preclinical injury of the nigrostriatal system that could later proceed into PD. To investigate the ability of ultrasonography to detect markers of SN degeneration, such as iron deposition and neuromelanin depletion, we scanned postmortem brains from normal subjects at different ages by ultrasound and measured the echogenic area of the SN. The SN was then dissected and used for histological examinations and determination of iron, ferritin, and neuromelanin content. A significant positive correlation was found between the echogenic area of the SN and the concentration of iron, H- and L-ferritins. Multivariate analysis carried out considering the iron content showed a significant negative correlation between echogenicity and neuromelanin content of the SN. In PD, a typical loss of neuromelanin and increase of iron is observed in this brain area. The finding of a positive correlation between iron and ferritin levels and a negative correlation of neuromelanin content with the area of echogenicity at the SN could therefore provide an interesting basis for diagnosis and therapeutic follow-up studies in PD.

Apoferritins↗

PubMed2001

Whole body detection and imaging of nitric oxide generation in mice following cardiopulmonary arrest: detection of intrinsic nitrosoheme complexes.

Ischemic tissues generate nitric oxide (NO) by direct reduction of tissue nitrite under the acidic conditions that occur during ischemia. In view of the important implications of this enzyme-independent mechanism of NO generation on the pathogenesis and treatment of tissue injury, the NO formation in mice subjected to cardiopulmonary arrest was measured and imaged. Real-time measurement of NO generation was performed by detection of naturally generated NO-heme complexes in tissues using L-band electron paramagnetic resonance (EPR) spectroscopy. To distinguish NO generated from nitrite, animals were labeled with isotopically enriched (15)N-nitrite. Mice were infused with nitrite (70 mg/kg, intravenous), cardiopulmonary arrest induced by an overdose of phenobarbital, and transferred to the EPR resonator. Measurements of NO generation were performed on the intact animal at the levels of the head, thorax, and abdomen. At the end of 3 hr, major organs were isolated and analyzed for their NO signal. The NO complexes were found to have maximum levels in lung, heart, and liver. Three-dimensional spatial mapping of the NO complex in the intact animal subjected to cardiopulmonary arrest was performed using EPR imaging techniques. The images also confirmed the maximum formation in the lungs, heart, and liver. The present data reveal that mice subjected to cardiopulmonary arrest generate large amounts of NO, which is nitrite mediated. The observed signal was largely due to heme-bound NO, which accounted for the high concentrations found in these organs. This increased NO formation during cardiopulmonary arrest could contribute to the difficulty of resuscitation after long periods of arrest. Magn Reson Med 45:700-707, 2001.

Animals↗

PubMed1995

Detection of expanded CAG repeats in bipolar affective disorder using the repeat expansion detection (RED) method.

Genetic factors are of major aetiological importance in Bipolar Affective Disorder (BPAD type I and II). The exact mode of inheritance of BPAD is unknown, but the recent demonstration of anticipation suggests that dynamic mutations could be involved in the clinical expression of the disease. We have used the repeat expansion detection (RED) method to test whether the anticipation in BPAD could be explained by the presence of expanded trinucleotide repeat sequences. Using a (CTG)10 oligonucleotide a significantly higher number of expanded CAG repeats were found in the genomic DNA of two independent samples of unrelated BPAD patients of Swedish and Belgian ancestry as compared with normal controls. The difference in repeat number was more consistent if data of the two samples of patients was pooled. In this study a CAG trinucleotide repeat expansion was associated for the first time with a major psychiatric disorder. It is possible that the CAG trinucleotide repeat expansion is involved in the clinical expression of BPAD and that it is the molecular basis explaining the phenomenon of anticipation observed in this disorder.

Aged↗