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PubMed1975

0-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine hydrochloride as a sensitive derivatizing agent for the electron capture gas liquid chromatographic analysis of keto steroids.

0-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine hydrochloride was used to prepare oximes of steroids with keto groups in selected positions; 3,17 and 20-monoketo; 3,17 and 3,20-diketo. Some of the 3-keto steroids had hindered 17-hydroxyl groups which were not readily amenable to esterification with perfluoroanhydrides, the most commonly used derivatizing agents for electron capture gas chromatographic analysis of hydroxy steroids. The oximes were readily prepared from 5 ng of each of the compounds tested, and with testosterone it was demonstrated that the derivative could be prepared from as little as 0.1 ng. The derivatives were stable to gas chromatography and extremely sensitive to electron capture detection. The sensitivity ranged from 1.5 X 10(4) coulombs per mole of progesterone. Because of the ease of preparation of the derivatives, their stability in common solvents and analytical manipulative techniques, the reagent would be suitable for the micro analysis of biologically significant keto steroids by electron capture gas chromatography.

Chromatography, Gas↗

PubMed1976

A comparison of electron-capture GLC, electrolytic-conductivity GLC and UV-absorption HPLC for the analysis of some herbicides in foods.

A comparison of gas chromatography with electron-capture or electrolytic-conductivity (nitrogen mode) detection, and high-pressure liquid chromatography (HPLC) with UV-absorption detection (254 nm) was carried out for the analysis of several herbicides in foods. Linuron, propanil, terbacil, benzoylprop-ethyl, and the fungicide DCNA in samples of cabbage, corn, potato, and wheat spiked at 2 and 0.2 ppm were examined. The pesticides were extracted with acetone, partitioned into petroleum ether-methylene chloride, and cleaned up on a 2% deactivated Florisil column before direct chromatographic analysis. Electron-capture gas-liquid chromatography (GLC) was most suitable for DCNA and benzoylprop-ethyl while UV-absorption HPLC was best for terbacil analysis. Linuron and propanil gave similar results for both electron-capture GLC and HPLC. Electrolytic-conductivity GLC could detect all pesticides at the 0.2 ppm level and exhibited the least number of extraneous peaks in the chromatograms.

Aniline Compounds↗

PubMed2000

Estimation of the prevalence of epilepsy in the Benin region of Zinvié using the capture-recapture method.

BACKGROUND: The prevalence of epilepsy was estimated in two villages of 3134 inhabitants, in Benin, in April and May 1997 using the capture-recapture method. METHODS: Information was obtained from (i) a door-to-door cross-sectional study, (ii) a non-medical source consisting of key informants (traditional practitioners, teachers, village leaders, and religious representatives) and (iii) a medical source through evaluation of medical records in health centres. In all the three situations, the diagnosis of epilepsy was confirmed by a neurologist. RESULTS: The door-to-door survey found 50 epileptics, i.e. a prevalence of 15.9 per 1000. The non-medical source found 26 patients. The medical source found only four patients. In total, 66 epileptics were found by combining the three sources, giving a prevalence of 21.1 per 1000. After application of the capture-recapture method, the estimated number of cases from the door-to-door survey and non-medical source was 105, and 110 cases when the medical source was considered as well. The respective prevalences were 33.5 per 1000, and 35.1 per 1000. CONCLUSIONS: The door-to-door survey has been usefully improved by using key informants. The epilepsy prevalence estimate found by capture-recapture is clearly higher than that found by traditional cross-sectional methods, and could better depict the frequency of epilepsy in Africa.

Adolescent↗

PubMed2000

Estimating deaths from industrial injury by capture-recapture: a cautionary tale.

BACKGROUND: Capture-recapture methods are increasingly being used to improve surveillance for a number of diseases. However, concerns persist regarding the validity of estimates obtained. METHOD: Capture-recapture methods were applied to estimate the ability of four separate data sources on occupational fatalities to predict the 237 deaths ('gold standard') we determined from a special in-depth study of medical examiner records. RESULTS AND CONCLUSION: Capture-recapture results based upon the four sources vary according to different models. However, both separately and in aggregate of industry type and cause of death, most models seriously underestimate the gold standard, and give a misleading impression of precision of the estimate of hidden individuals. It is commonly believed that reliable estimates from such methods require lists with high coverage and parsimonious models. Here, to obtain an estimate consistent with the gold standard, the list with almost complete coverage must be discarded and a complex model fitted. It is argued that this conclusion is of widespread application.

Accidents, Occupational↗

PubMed2003

Recent transmission of tuberculosis in Madrid: application of capture-recapture analysis to conventional and molecular epidemiology.

BACKGROUND: Population-based studies using a combination of molecular techniques and conventional epidemiological methods have been used to study the dynamics of tuberculosis (TB) transmission but the relative utility of each technique has not yet been established. METHODS: A prospective population-based molecular and epidemiological study of patients diagnosed with TB was conducted in three urban districts of Madrid (Spain) during 1997-1999. Analysis was performed using the capture-recapture method including covariates in which conventional epidemiological data and the information on clustered cases obtained by DNA fingerprinting were regarded as independent and complementary procedures. RESULTS: The estimate obtained by molecular analysis alone, that 31.6% of TB cases were due to recent transmission, was revised to 44.8% (95% CI: 31.4-58.2) using the capture-recapture method. The estimated completeness of the combined databases for identification of recent transmission was 59.2%. Underestimation of the true prevalence of recent transmission was higher with conventional epidemiology than molecular analysis, particularly for patients <35 years old and those with a history of imprisonment. CONCLUSIONS: In this study, use of the capture-recapture technique allowed us to combine epidemiological information obtained by conventional and molecular methods to quantify the number of cases of recently transmitted TB in the community and identify specific populations at high risk of disease. This information is clearly important because such groups are a prime target for improved TB control measures. In the long term, this combination of techniques may contribute significantly to control the spread of TB.

Adult↗

PubMed2003

"Search-and-capture" of microtubules through plus-end-binding proteins (+TIPs).

The generation of a polarized microtubule organization is critically important for proper cellular functions, such as cell division, differentiation and migration. Microtubules themselves are highly dynamic structures, and this dynamic property is temporally and spatially regulated within cells, especially at their plus ends. To explain how microtubules set up and make contacts with cellular structures, a "search-and-capture" mechanism has been proposed, in which the microtubule plus ends dynamically search for and capture specific sites, such as mitotic kinetochores and cell cortex. To date, several classes of proteins have been shown to be associated with microtubule plus ends in a wide range of organisms from fungi to humans and to play critical roles in the "search-and-capture" mechanism. In this review, we overview our current understanding of the "plus-end-binding proteins" (+TIPs), including APC (adenomatous polyposis coli) tumor suppressor protein, cytoplasmic linker proteins (CLIPs), CLIP-associating proteins (CLASPs), cytoplasmic dynein/dynactin, and EB1, an APC-interacting protein.

Adenomatous Polyposis Coli Protein↗

PubMed1990

Age distribution of adult female screwworms (Diptera: Calliphoridae) captured on sentinel animals in the coastal lowlands of Guatemala.

The age structure of screwworm, Cochliomyia hominivorax (Coquerel), populations was studied in the Guatemalan lowlands with the pteridine technique of age determination. Flies (95% were 4-15 d old) were captured on sentinel animals. Mean age was 7.5 d. The oldest fly captured was 21 d old. Most flies visiting wounds were reproductively mature females. Of these, about one-half oviposited once, one-third oviposited twice, and 1 in 10 completed three ovarian cycles (assuming a 3-d interval between clutches). Periodicity in adult capture rates may be related to the reproductive cycle. Results suggest that local populations are composed of a high proportion of synchronized cohorts.

Animals↗

PubMed2004

Two low-cost food attractants for capturing Toxotrypana curvicauda (Diptera: Tephritidae) in the field.

Adults of the papaya fruit fly, Toxotrypana curvicauda Gerstaecker, living in wild vegetation in Yautepec, Morelos, Mexico, were captured using McPhail traps baited with pineapple juice or brown sugar. Maximum capture peaks occurred during August and November in the afternoon. Baits were most effective when aged over a 4-d period. Traps baited with brown sugar captured the highest number of adults, and both baits were more attractive to females than males. Potential use of these baits for pest management and research is discussed, considering that this is the first report of pineapple juice being attractive to the papaya fruit fly.

Ananas↗

PubMed2005

Factors affecting male Prays oleae (Lepidoptera: Yponomeutidae) captures in pheromone-baited traps in olive orchards.

Effects of trap design, height and side of trap placement on olive trees, pheromone doses in dispensers, aging of dispensers in the field, and secondary pheromone components were evaluated for the development of an effective pheromone monitoring system for Prays oleae (Bernard) Lesne (Lepidoptera: Yponomeutidae) in olive orchards. Field trials showed that trap design, pheromone dose, and trapping side affected male captures, whereas dispenser age, trap height, and secondary components had no influence. Pherocon 1C and Delta traps baited with 1 mg of (Z)-7-tetradecenal captured more male moths than Pherocon II or Funnel traps. Placement of traps at different cardinal directions significantly affected captures, but this trend was not consistent and varied with flight period and trap position internal or external to the tree canopy. Moth phenology as determined by pheromone traps from early April to mid-October was consistent with published field data. Results indicate that Pherocon 1C or Delta traps baited with 1 mg of (Z)-7-tetradecenal provide an effective tool for monitoring the flight activity of P. oleae and the time of application of control measures.

Animals↗

PubMed2004

Prevalence of problematic cocaine consumption in a city of southern Europe, using capture-recapture with a single list.

This study aims to determine the magnitude and characteristics of problematic cocaine consumption in the city of Barcelona, Spain. Capture-recapture with a single source was used to estimate prevalence. Log-linear regression models with interaction terms were fitted to the total sample and to subgroups according to other drugs consumed. Emergency room indicator data were obtained from the Barcelona Drug Information System. Drug-related emergencies of Barcelona residents for 1999 were analyzed. During 1999, a total of 4,035 drug-related emergencies were seen in Barcelona hospitals. Of these, 1,656 (41%) involved cocaine consumption; 41% of these patients had consumed cocaine with an opiate; 29% used cocaine with other substances; and 30% used cocaine alone. It was estimated that there was a total of 25,988 problematic cocaine users (95% confidence interval 11,782-58,064), yielding a rate of 31.27 per 1,000 inhabitants aged 15 to 54 years (95% confidence interval 14.2-69.9). The number of cocaine-related emergencies was high enough to allow capture-recapture to be applied, thus obtaining an estimate of the prevalence of problematic cocaine consumption, and high enough to characterize users according to different profiles. The use of capture-recapture with a single source can be interesting for problems related to the urban context.

Adult↗

PubMed2002

Solid phase capturable dideoxynucleotides for multiplex genotyping using mass spectrometry.

We report an approach using solid phase capturable biotinylated dideoxynucleotides (biotin-ddNTPs) in single base extension for multiplex genotyping by mass spectrometry (MS). In this method, oligonucleotide primers that have different molecular weights and that are specific to the polymorphic sites in the DNA template are extended with biotin-ddNTPs by DNA polymerase to generate 3'-biotinylated DNA products. These products are then captured by streptavidin-coated solid phase magnetic beads, while the unextended primers and other components in the reaction are washed away. The pure extension DNA products are subsequently released from the solid phase and analyzed by matrix-assisted laser desorption/ionization time-of-flight MS. The mass of the extension products is determined using a stable oligonucleotide as a common internal mass standard. Since only the pure extension DNA products are introduced to the MS for analysis, the resulting mass spectrum is free of non-extended primer peaks and their associated dimers, which increases the accuracy and scope of multiplexing in single nucleotide polymorphism (SNP) analysis. The solid phase purification approach also facilitates desalting of the captured oligonucleotides, which is essential for accurate mass measurement by MS. We selected four biotin-ddNTPs with distinct molecular weights to generate extension products that have a 2-fold increase in mass difference compared to that with conventional ddNTPs. This increase in mass difference provides improved resolution and accuracy in detecting heterozygotes in the mass spectrum. Using this method, we simultaneously distinguished six nucleotide variations on synthetic DNA templates mimicking mutations in the p53 gene and two disease-associated SNPs in the human hereditary hemochromatosis gene.

Biotinylation↗

PubMed1995

Use of capture-recapture to estimate the prevalence of opiate addiction in Barcelona, Spain, 1989.

It is difficult to obtain accurate prevalence estimates of opiate addiction with direct methods. The capture-recapture method has been used to estimate the prevalence of hidden populations, including opiate addicts. In this study, we applied capture-recapture, including log-linear modeling, to estimate the prevalence of opiate addicts in Barcelona, Spain. Anonymous identification data from three 1989 sources (hospital emergency rooms, treatment admissions, and heroin overdose deaths) in Barcelona were used to obtain population samples. For prevalence estimation, two strategies were followed: 1) emergency room data only, divided into trimesters; and 2) all three sources used simultaneously. Estimates based only on emergency room data were lower than estimates obtained by the simultaneous analysis of all three data sources; the latter estimates gave narrower confidence intervals (6,324-7,414 addicts), giving a prevalence for Barcelona in 1989 of between 8.5 and 9.9 opiate addicts per 1,000 residents aged 15-44 years. The estimated prevalence varied by sex and age group and was highest in males aged 15-29 years (between 17.1 and 21.2). At least 42% had contacted one or more of the services studied, although only one in seven had been admitted for treatment during 1989. Capture-recapture is the election method for prevalence estimation when direct methods are not feasible.

Adolescent↗

PubMed1995

Efficiency and accuracy of disease monitoring systems: application of capture-recapture methods to injury monitoring.

Capture-recapture methods were employed to determine the most accurate and efficient approaches to monitor adolescent injuries. Multiple sources were used to ascertain cases of adolescent injuries that occurred between September 1 and December 31, 1991, in a single school district in metropolitan Pittsburgh, Pennsylvania. Eliminating the duplicate cases between the sources revealed 144 verified injuries; 127 (88.2%) were identified by student monthly recalls, 33 (22.9%) by daily attendance records, 58 (40.3%) by medical excuses, and 72 (50.0%) by a 4-month student recall. Capture-recapture analyses were undertaken to assess potential dependencies between the sources, to estimate the degree of underascertainment in the population, and to evaluate the efficiency of the individual sources and the combinations between them. It was estimated that 91% of the cases in the population were ascertained when all four methods of case finding were utilized. Furthermore, the analysis indicated that accurate injury estimates could be achieved using combinations of only two or three of the sources. An analysis of the efficiency of the methods of ascertainment revealed a trade-off between effort (the number of hours needed to identify cases) and the precision (coefficient of variation) of the injury estimates. Capture-recapture analysis not only provided an approach to evaluate and adjust for undercount but also offered a formal means to evaluate the most efficient combination of the sources to maximize completeness while minimizing effort. The use of these techniques has the potential to evaluate and improve injury surveillance as well as other disease monitoring systems.

Adolescent↗

PubMed1992

Rate-dependent failure of ventricular capture in patients treated with oral propafenone.

The effects of propafenone on ventricular excitability were studied in 18 patients after 9 +/- 6 days on oral propafenone (900 mg/day). Late diastolic double threshold right ventricular stimulation was performed at variable rates. In five patients (28%, group I) an intermittent, rate-dependent failure of ventricular capture was reproducibly observed during stimulation at rates above the sinus rhythm but not exceeding 150 beats min-1. In four patients loss of capture was preceded by gradual prolongation of the interval between the stimulus artifact and the local right ventricular bipolar electrogram. Such findings were not observed in the remaining 13 patients (group II) on propafenone nor in 28 studies in the same patients on different antiarrhythmic agents. Group I vs group II patients were older (72 +/- 4 vs 53 +/- 18 years, P = 0.002), had longer right ventricular effective refractory periods on the baseline (P = 0.004) and on propafenone (P = 0.0003), and had longer QRS duration on propafenone. The increase produced by propafenone in sinus rhythm QRS duration, paced QRS duration and ventricular effective refractory period was greater in group I than in group II: 42 +/- 36 vs 14 +/- 12 ms, P = 0.01, 94 +/- 43 vs 34 +/- 26 ms, P = 0.0002, 88 +/- 64 vs 22 +/- 37 ms, P = 0.025, respectively. Thus propafenone can produce rate-dependent failure of ventricular capture which is associated with marked prolongation of refractoriness and QRS duration suggesting a marked use-dependent drug effect in selected patients.

Administration, Oral↗

PubMed1997

Ease of capture in Japanese quail of two lines divergently selected for adrenocortical response to immobilization.

Divergent lines of Japanese quail have been genetically selected over several generations for a reduced (low stress, LS) or an exaggerated (high stress, HS) plasma corticosterone response to brief mechanical restraint. Female quail were housed in one mixed-line group (18LS + 18 HS) in one of the top-tier compartments of a brooder. At 32 d of age, the quail were removed individually by the experimenter, their identity and position in the order of capture were noted, and then they were placed in a separate compartment. Following brief respites, this procedure was repeated on 16 occasions. No differences were found between HS and LS quail in their ease of capture and no linear trends were apparent upon repeated testing of either strain. These findings have positive connotations for management and welfare because, although selection for a reduced adrenocortical stress response to restraint has apparently been accompanied by reduced fearfulness, it has not resulted in a potential and undesirable increase in the difficulty of capture and handling. Further, the significant tendencies found within and across lines for individual birds to be caught at similar stages of each trial has important implications for behavioral studies that involve putatively random sampling of a population.

Adrenal Cortex↗

PubMed2005

Chemical effects in biological systems--data dictionary (CEBS-DD): a compendium of terms for the capture and integration of biological study design description, conventional phenotypes, and 'omics data.

A critical component in the design of the Chemical Effects in Biological Systems (CEBS) Knowledgebase is a strategy to capture toxicogenomics study protocols and the toxicity endpoint data (clinical pathology and histopathology). A Study is generally an experiment carried out during a period of time for the purpose of obtaining data, and the Study Design Description captures the methods, timing, and organization of the Study. The CEBS Data Dictionary (CEBS-DD) has been designed to define and organize terms in an attempt to standardize nomenclature needed to describe a toxicogenomics Study in a structured yet intuitive format and provide a flexible means to describe a Study as conceptualized by the investigator. The CEBS-DD will organize and annotate information from a variety of sources, thereby facilitating the capture and display of toxicogenomics data in biological context in CEBS, i.e., associating molecular events detected in highly-parallel data with the toxicology/pathology phenotype as observed in the individual Study Subjects and linked to the experimental treatments. The CEBS-DD has been developed with a focus on acute toxicity studies, but with a design that will permit it to be extended to other areas of toxicology and biology with the addition of domain-specific terms. To illustrate the utility of the CEBS-DD, we present an example of integrating data from two proteomics and transcriptomics studies of the response to acute acetaminophen toxicity (A. N. Heinloth et al., 2004, Toxicol. Sci. 80, 193-202).

Acetaminophen↗

PubMed1992

Isolation and characterization of a new chimpanzee lentivirus (simian immunodeficiency virus isolate cpz-ant) from a wild-captured chimpanzee.

OBJECTIVE: To assess the prevalence of infection with simian immunodeficiency virus (SIV) isolate cpz, a lentivirus closely related to HIV-1, in chimpanzees, and to obtain new SIVcpz isolates. METHODS: Forty-four wild-captured chimpanzees in Belgium and Côte d'Ivoire were tested for HIV and SIV antibodies. Virus was isolated from the peripheral blood lymphocytes of positive animals and characterized by electron microscopy, Western blot and radioimmunoprecipitation assay. RESULTS: One animal had antibodies that cross-reacted with HIV-1. A lentivirus was isolated and referred to as SIVcpz-ant. With regard to molecular weight patterns, SIVcpz-ant differs from SIVcpz-gab' an HIV-1-related virus isolated from a wild-captured chimpanzee in Gabon. The major core protein, the transmembrane and outer membrane glycoproteins of the SIVcpz-ant strain consistently had higher molecular weights. Significantly more HIV-1-positive sera reacted with the envelope proteins of the Gabonese SIVcpz-gab strain than with the SIVcpz-ant strain. CONCLUSIONS: This study shows that natural infection of wild-captured chimpanzees with an HIV-related virus may not be uncommon. The diversity of the two chimpanzee isolates, the different geographical origin and the absence of disease suggest that chimpanzees have not recently become SIVcpz-infected.

Animals↗

PubMed2000

Use of the capture-recapture method to estimate severe traumatic brain injury rates.

OBJECTIVE: This study assessed the applicability of using three different data sources (hospital discharge data, Traumatic Brain Injury Registry data, and death certificates) to identify high-risk groups for traumatic brain injuries (TBI). Reporting biases were also addressed. METHODS: Linkage of the data sources and log-linear modelling in conjunction with the capture-recapture method was used to estimate the number of missing TBI. Biased reporting to each data source was assessed by using the total number of estimated TBI by age and sex. RESULTS: An estimated 2% of TBI that occurred in Iowa were not reported to any of the data sources. Overall, women 85 years old and older were more likely to be missed by the combined data sources. Males and those of advanced age were less likely to be reported to the Registry. By using the capture-recapture method, falls among the elderly were found to be a significant public health problem in Iowa. CONCLUSION: Despite biased reporting to the three data sources, the capture-recapture method can be used to identify high-risk groups for TBI in Iowa.

Accidental Falls↗