SEARCH · PubMed Health

Results for “Capture”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 595 records · Page 33Linked to original sources

PubMed2005

Oculomotor consequences of abrupt object onsets and offsets: onsets dominate oculomotor capture.

Previous research has shown that the appearance of an object (onset) and the disappearance of an object (offset) have the ability to influence the allocation of covert attention. To determine whether both onsets and offsets have the ability to influence eye movements, a series of experiments was conducted in which participants had to make goal-directed eye movements to a color singleton target in the presence of an irrelevant onset/offset. In accord with previous research, onsets had the ability to capture the eyes. The offset of an object demonstrated little or no ability to interrupt goal-directed eye movements to the target. Two experiments in which the effects of onsets and offsets on covert attention were examined suggest that offsets do not capture the eyes, because they have a lesser ability to capture covert attention than do onsets. A number of other studies that have shown strong effects of offsets on attention have used offsets that were uncorrelated with target position (i.e., nonpredictive), whereas we used onsets and offsets that never served as targets (i.e., antipredictive). The present results are consistent with a new-object theory of attentional capture in which onsets receive attentional priority over other types of changes in the visual environment.

Adolescent↗

PubMed2001

Contingent attentional capture or delayed allocation of attention?

Under certain circumstances, external stimuli will elicit an involuntary shift of spatial attention, referred to as attentional capture. According to the contingent involuntary orienting account (Folk, Remington, & Johnston, 1992), capture is conditioned by top-down factors that set attention to respond involuntarily to stimulus properties relevant to one's behavioral goals. Evidence for this comes from spatial cuing studies showing that a spatial cuing effect is observed only when cues have goal-relevant properties. Here, we examine alternative, decision-level explanations of the spatial cuing effect that attribute evidence of capture to postpresentation delays in the voluntary allocation of attention, rather than to on-line involuntary shifts in direct response to the cue. In three spatial cuing experiments, delayed-allocation accounts were tested by examining whether items at the cued location were preferentially processed. The experiments provide evidence that costs and benefits in spatial cuing experiments do reflect the on-line capture of attention. The implications of these results for models of attentional control are discussed.

Adolescent↗

PubMed2001

Attentional capture with various distractor and target types.

Effects of nonpredictive distractors that involved changes in luminance, size, or shape were examined in three experiments. In Experiment 1, with two types of distractors (onsets and offsets), accuracy was better on trials when the distractor was near the location of either an offset or an onset target than on trials when the distractor was in a different location from that of the target, demonstrating attentional capture. Capture occurred both when the type of target (onset or offset) was blocked and therefore predictable and also when the type of target was mixed within blocks and therefore not predictable. Further experiments indicated that distractors captured attention even when the change to distractor did not create a new perceptual object. Neither a singleton-detection mode, nor a contingent involuntary orienting hypothesis, nor creation of a new object seems to explain all of these data adequately. Rather, capture may depend on a number of factors in the task.

Adolescent↗

PubMed2002

Made you blink! Contingent attentional capture produces a spatial blink.

Previous studies have shown that the capture of attention by an irrelevant stimulus can be eliminated by fore knowledge of the spatial location of the relevant target stimulus. To explore whether spatial certainty is sufficient to eliminate capture, four experiments are reported in which the spatial location of the target is certain but the temporal position is uncertain. Subjects viewed a central rapid serial visual presentation stream in which a target letter was defined by a particular color (e.g., red). On critical trials, irrelevant color singletons appeared in the periphery. In Experiments 1 and 2, peripheral singletons produced a decrement in central target identification that was contingent on the match between the singleton color and the target color. Experiments 3 and 4 provided evidence that this decrement reflected a shift of spatial attention to the location of the distractor. The results suggest that spatial certainty is not sufficient to eliminate attentional capture and that attentional capture can result in a spatial "blink" that is conditional on top-down attentional control settings.

Attention↗

PubMed2005

Attention capture is modulated in dual-task situations.

Because some features affect the efficiency of visual search even when they are irrelevant to the task, they are thought to capture attention in a stimulus-driven manner. If such attention shifts are stimulus driven, they should be unaffected by reduced resources. We added a concurrent auditory task to a traditional attention capture paradigm and found that capture by an irrelevant, abruptly appearing stimulus (i.e., an onset) was eliminated. In contrast, prioritization of an irrelevant color singleton--a stimulus that at most receives only mild prioritization in this paradigm--was increased under dual-task conditions. These results challenge the hypothesis that attention capture by irrelevant features is stimulus driven. Instead, prioritization depends on and is modulated by the availability of resources.

Attention↗

PubMed1997

Offset transients modulate attentional capture by sudden onsets.

Recent research with visual search tasks has suggested that stimuli which appear as sudden onsets (new objects) have attentional priority over stimuli that are created by removing segments of premasks (non-onset stimuli). Attentional capture by sudden onsets occurs despite the fact that the appearance of these new objects predicts neither the identity nor the location of the target in the visual search task. In three experiments, we examined the extent to which attentional capture by sudden onsets could be modulated by offset transients used to create non-onset objects. To that end, we systematically manipulated the ratio of non-onset to onset stimuli in the display (display ratio) as well as the ratio offset to onset segments between the stimulus types (stimulus ratio). Increases in either the stimulus ratio or the display ratio resulted in increases in the visual search for the onset targets. These results suggest that the ability of sudden onsets (new objects) to capture attention is influenced by stimulus-driven factors, such as environmental change. Interestingly, the results also indicated that goal-directed or purposeful search for sudden-onset (new object) targets was relatively uninfluenced by the amount of change in the visual display. Therefore, it would appear that environment change has differential effects on goal-directed and stimulus-driven search. These results are discussed in terms of their implications for our understanding of attentional capture.

Attention↗

PubMed2005

Temporal expectations modulate attentional capture.

Subjects' ability to override attentional capture by salient distractors during singleton search has been attributed to the adoption of an attentional set for the type of discontinuity characterizing the target (Folk, Remington, & Johnston, 1992) or to fast disengagement of attention from the salient distractor's location (Theeuwes, Atchley, & Kramer, 2000). The present results support an alternative account by showing that temporal expectancies modulate attentional capture. In a color singleton search, an irrelevant onset preceding the target by a given time interval produced capture when the distractor-to-target interval varied unpredictably but failed to do so when this interval was predictable. Moreover, with unpredictable intervals and moderately salient stimuli, capture was overridden at the expected average interval. These findings invite caution when stimulus onset asynchrony manipulations are used to study the temporal deployment of attention, since they demonstrate that such manipulations introduce powerful temporal expectations.

Attention↗

PubMed2000

Attentional capture by abrupt onsets and feature singletons produces inhibitory surrounds.

Two experiments found that form discriminations to a target item were inhibited when the target appeared adjacent to an attentionally salient item. Experiment 1 manipulated the attentional salience of an irrelevant color singleton through the attentional set adopted by the subjects. Color singletons captured attention when the target was itself a feature singleton, but not when the target was defined as a conjunction of features. Attentional capture was accompanied by an inhibitory region (i.e., slowed target reaction times), which dissipated with distance from the color singleton. In Experiment 2, the attentional salience of abrupt onsets and color singletons was compared. Irrelevant abrupt onsets captured attention, whereas irrelevant color singletons failed to capture attention. Again, an inhibitory region surrounded the attentionally salient abrupt onsets, but not the color singletons. The results are discussed in the context of current models of visual spatial attention and suggest a distinction between attentional preparation and attentional selection.

Adult↗

PubMedDate not supplied

Posterior continuous curvilinear capsulorhexis with and without optic capture of the posterior chamber intraocular lens in the absence of vitrectomy.

PURPOSE: To evaluate the efficacy of posterior continuous curvilinear capsulorhexis (PCCC) with optic capture of the posterior chamber intraocular lens (PC IOL) in the absence of vitrectomy in preventing secondary opacification of the visual axis following pediatric cataract surgery. PATIENTS AND METHODS: Thirty-four eyes of 28 children with congenital or developmental cataract, aged 1.5 to 12 years (mean, 6.39 years), were included in this prospective, randomized study. Anterior continuous curvilinear capsulorhexis (ACCC) with PCCC without optic capture of the PC IOL was performed in group A (18 eyes) and ACCC with PCCC with optic capture of the PC IOL was performed in group B (16 eyes). None of the eyes underwent anterior vitrectomy. Secondary opacification of the visual axis, visual acuity, and possible complications were observed and analyzed. RESULTS: The follow-up period ranged from 8 to 28 months (mean, 17.5 months). All 16 eyes (100%) in group B had a clear visual axis at the end of follow-up. Eight eyes (44.4%) in group A had significant opacification of the visual axis. The difference between the two groups was statistically significant (P = .0011). No eye in group B required secondary intervention, whereas all 8 eyes in group A with significant secondary opacification required secondary intervention. There was no statistically significant difference in other complications such as anterior chamber reaction, fibrin formation, lenticular precipitates, and posterior synechiae. The final best-corrected visual acuity at the end of follow-up was comparable in the two groups (P > .05). CONCLUSION: PCCC with optic capture of the PC IOL prevents secondary opacification of the visual axis even in the absence of vitrectomy.

Capsulorhexis↗

PubMed2006

Cryptococcus neoformans glycoantigens are captured by multiple lectin receptors and presented by dendritic cells.

Cell-mediated immune responses to glycoantigens have been largely uncharacterized. Protective T cell responses to the pathogenic yeast Cryptococcus neoformans are dependent on heavily mannosylated Ags termed mannoproteins. In the work presented, the innate immune response to mannoprotein was determined. Purified murine splenic dendritic cells (DC), B cells, and macrophages were used to stimulate mannoprotein-specific T cells. Only DC were capable of any measurable stimulation. Depletion of DC resulted in the abrogation of the T cell response. Human and murine DC rapidly captured fluorescent-labeled mannoprotein by a mannose receptor-mediated process. Using transfected cell lines, the type II C-type lectin receptor DC-specific ICAM-3-grabbing nonintegrin (CD209) was determined to have affinity for mannoprotein. Taken together with prior work demonstrating that mannoprotein was captured by the macrophage mannose receptor (CD206), these data suggest that multiple mannose receptors on DC recognize mannoprotein. Pulsing experiments demonstrated that DC captured sufficient mannoprotein over 2 h to account for 50% of total stimulation. Capture appeared dependent on mannose receptors, as competitive mannosylated inhibitors and calcium chelators each interfered with T cell stimulation. By confocal microscopy, intracellular mannoprotein trafficked to an endo-lysosomal compartment in DC, and at later time points extended into tubules in a similar fashion to the degradation marker DQ-OVA. Mannoprotein colocalized intracellularly with CD206 and CD209. These data suggest that DC provide the crucial link between innate and adaptive immune responses to C. neoformans via a process that is dependent upon the efficient uptake of mannoprotein by mannose receptors.

Animals↗

PubMed1994

Antigen-capture enzyme immunoassay: a comparison with other methods for the detection of spotted fever group rickettsiae in ticks.

To evaluate the prevalence of spotted fever group rickettsiae along the Adriatic Coast of Croatia, 832 ticks were examined by hemolymph test, direct immunofluorescence, antigen-capture enzyme immunoassay, and polymerase chain reaction. Very good agreement was observed among direct immunofluorescence, polymerase chain reaction, and antigen-capture enzyme immunoassay. Twelve ticks that were positive by hemolymph test and negative by both direct immunofluorescence and polymerase chain reaction presumably do not represent spotted fever group rickettsiae. By direct immunofluorescence, spotted fever group rickettsiae were present in 12% of Rhipicephalus bursa, 10.6% of Rh. sanguineus, and 7.8% of Dermacentor marginatus. From the 98 ticks containing rickettsia-like organisms by hemolymph test, seven spotted fever group rickettsial isolates were established in cell culture. Four isolates were identified as Rickettsia conorii. The antigen-capture enzyme immunoassay, which utilizes a monoclonal antibody to antigens of the 135-kD surface protein shared among many members of the spotted fever group, is recommended for primary screening of tick samples because it is reliable and yet less labor-intensive than the hemolymph and direct immunofluorescence tests. Although the polymerase chain reaction is too expensive for use as a screening method, it is recommended for confirmation of positive screening results. In addition to the technologic advance of the antigen-capture enzyme immunoassay, this study documented by contemporary methods that R. conorii is present along the eastern Adriatic Coast not only in the classic vector, Rh. sanguineus, but also in Rh. bursa and D. marginatus.

Animals↗

PubMed1998

Cystatin capture enzyme-linked immunosorbent assay for immunodiagnosis of human paragonimiasis and fascioliasis.

An ELISA was developed using chicken cystatin as a capture agent for the immunodiagnosis of paragonimiasis and fascioliasis. The assay detected specific antibodies to fluke cysteine proteinases without the need for purified proteinases. An ELISA plate was sensitized with chicken egg white cystatin, incubated with excretory-secretory (ES) products of adult flukes, and standard ELISA procedures were then followed. The ELISA plates incubated with the ES products of Paragonimus westermani and Fasciola sp. showed high reactivity to sera from patients with paragonimiasis westermani and fascioliasis, respectively. The capture ELISA showed little cross-reactivity with sera from patients with paragonimiasis and fascioliasis, which showed immunodiagnostic cross-reactivity in a conventional ELISA using crude fluke antigens. Moreover, the capture ELISA showed little reactivity with sera from patients with five other helminth diseases and from healthy volunteers. Omitting either sensitization with cystatin or incubation with fluke ES products abolished high ELISA reactivity, as did a prior exposure of the ES products to cystatin. The addition of papain to an incubation solution of the ES products greatly reduced ELISA reactivity. Incubating the cystatin-sensitized plates with partially purified cysteine proteinases from flukes instead of the ES products also maintained a similar high ELISA reactivity. These results indicate that the cystatin capture ELISA elicits a cystatin and fluke cysteine proteinase antigen-mediated reaction and measures fluke cysteine proteinase-specific antibodies. Prior exposure to low molecular weight inhibitors of cysteine proteinases and other proteinases, such as E-64, leupeptin, aprotinin, and pepstatin, had no effect, suggesting that these inhibitors can be added to cysteine proteinase preparations to prevent autoproteolysis. This assay has good sensitivity and high specificity and is useful for the immunodiagnosis of paragonimiasis and fascioliasis.

Animals↗

PubMed1999

Hospitalizations for suspected dengue in Puerto Rico, 1991-1995: estimation by capture-recapture methods. The Puerto Rico Association of Epidemiologists.

Capture-recapture estimations compare the results of 2 or more independent surveillance systems for the same event, and by measuring the degree of overlap between them, provide an estimate of the total number of events, and therefore the completeness of ascertainment in each system. The Puerto Rico Department of Health and the Dengue Branch of the Centers for Disease Control and Prevention (CDC) monitor dengue activity in Puerto Rico through 2 distinct surveillance systems: diagnostic specimens from patients with suspected dengue and infection control nurses' reports on patients hospitalized for suspected dengue. The patient listings from these systems were used in a 2-sample, capture-recapture calculation to estimate the total number of persons with suspected dengue hospitalized from 1991 to 1995. The laboratory positivity rate for suspected dengue cases who submitted appropriately timed serum samples in those years ranged from 72.1% to 81.2%. The laboratory-based (diagnostic sample) surveillance system (routinely used to monitor hospitalizations for suspected dengue) detected an average of 1,197 hospitalized cases during non-epidemic years, and 4,329 cases during the epidemic year of 1994. The detection rate of this system averaged 42% of the numbers derived by the capture-recapture method. In non-epidemic years, an estimated average of 2,791 patients (range = 1,553-3,481) was estimated to have been hospitalized with a clinical diagnosis of dengue, compared with 9,479 during 1994. These results demonstrate the under-detection inherent in passive surveillance systems for hospitalized cases of suspected dengue, and illustrate the value of capture-recapture techniques to better estimate the true incidence of hospitalizations for this disease.

Adult↗

PubMed2007

Low-level genomic instability is a feature of papillary thyroid carcinoma: an array comparative genomic hybridization study of laser capture microdissected papillary thyroid carcinoma tumors and clonal cell lines.

CONTEXT: Previous chromosomal comparative genomic hybridization (CGH) studies of papillary thyroid carcinoma (PTC) have demonstrated a low prevalence of aberrations, with the majority of tumors showing no evidence of chromosomal instability. The technique of CGH can be optimized, however, using array CGH and laser capture microdissection to ensure pure cell populations for analysis. OBJECTIVE: To assess PTC using array CGH applied to laser capture microdissected tumor cells and pure cell cultures. DESIGN: Well-characterized PTC (known ret/PTC and BRAF mutation status), including samples from 5 tumors with classic morphology, 3 follicular variant tumors, and 3 clonal PTC cell lines, were analyzed. RESULTS: Copy gain and loss occurred in all of the tumor cases and cell lines examined. The most common recurrent aberrations involved gains on chromosomes 1, 5, 7, 11, 15, 17, and 22, with recurrent deletions occurring on chromosomes 4, 18, and 19. Analysis of the data from the 8 tumor samples showed that amplifications of TP73 (1p36.33), SNRPN (15q12), and PDGFB (22q13.1) occurred exclusively in tumors with a wild type BRAF. CONCLUSIONS: This study shows a higher prevalence of aberrations detected using array CGH allied to laser capture microdissection than previously described in the literature, and it appears that the combination of laser capture microdissection and arrayed clones optimizes studies utilizing CGH. Copy gain of PDGFB occurs in a subset of tumors showing no evidence of mutated BRAF or rearranged ret, suggesting that copy gain of PDGFB may underlie the increased expression of platelet-derived growth factor described recently in the literature.

Adult↗

PubMed1987

Capture methods in five subspecies of free-ranging bighorn sheep: an evaluation of drop-net, drive-net, chemical immobilization and the net-gun.

Six hundred thirty-four bighorn sheep (Ovis canadensis) were captured in the western United States between 1980 and 1986, using four different methods: drop-net (n = 158), drive-net (n = 249), chemical immobilization (n = 90) and net-gun (n = 137). The net-gun was found to have considerable advantages over the use of ground nets and chemical immobilization methods for capturing bighorn sheep. Evaluation of specific outcome categories for individual sheep, including normal, compromised (stress-induced), mortality from capture myopathy (CM), and accidental mortality, revealed significant differences in these rates between capture groups (P less than 0.05). The use of the net-gun resulted in the lowest proportion of compromised sheep at 11% (15/137), had no CM mortality, and resulted in a 2% (2/137) accidental mortality. The use of drop-nets resulted in 15% compromised sheep (24/158), a CM mortality rate of 2% (3/158), and an accidental mortality rate of 1% (2/158). A similar proportion of sheep were compromised with the drive-nets (16%, 39/249). This method also had the highest CM mortality rate at 3% (7/249), and an accidental mortality rate of less than 1% (2/249). Chemical immobilization resulted in the most compromised sheep at 19% (17/90), had a CM mortality rate of 2% (2/90), and caused the most accidental deaths at 6% (5/90). Drop-nets and drive-nets were comparable when combining total mortality with rates for compromised bighorn sheep, 18% and 19%, respectively (29/158 and 48/249). Chemical immobilization had the highest combined measure of risk at 27% (24/90) and net-gun lowest at 12% (17/137).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1989

Concentration of creatine kinase and aspartate aminotransferase in the blood of wild mallards following capture by three methods for banding.

The concentration of the enzymes creatine kinase (CK) and aspartate aminotransferase (AST), that are released from damaged muscle, was measured in the blood of wild adult male mallards (Anas platyrhynchos) captured for banding in decoy and bait traps and by rocket net. The concentration of CK and to a lesser extent AST was elevated markedly in ducks captured by all methods, indicating muscle injury. The level of CK was significantly greater in ducks captured in decoy traps and rocket net than in those captured in bait traps. This elevation appeared to be related to the length of time the birds were restrained and to the method of restraint.

Animals↗

PubMed1993

Injuries and behavior of raccoons (Procyon lotor) captured in the Soft Catch and the EGG traps in simulated natural environments.

The behavior and injuries of raccoons held for 12 and 24 hr in the Soft Catch and the EGG traps were studied in simulated natural environments. Nine raccoons held for 12 hr in the Soft Catch received minor injuries. However, one of nine raccoons held for 24 hr in this trap mutilated itself. The EGG trap caused only minor injuries to nine raccoons held for 12 hr, and nine others held for 24 hr. Thus the EGG trap can be expected, at a 95% level of confidence, to hold > or = 70% of the raccoons on traplines for 24 hr without serious injury. Raccoons captured in the Soft Catch fought their surroundings more than the trap. Those captured in the EGG trap fought the trap more than their surroundings. During the 24-hr capture study, escape behavior was more intense during the first 12 hr of capture, during both day and night.

Animal Welfare↗

PubMed2003

Physiologic responses of grizzly bears to different methods of capture.

The physiologic effects of two methods of capture, chemical immobilization of free-ranging (FR) bears by remote injection from a helicopter and physical restraint (PR) by leg-hold snare prior to chemical immobilization, were compared in 46 grizzly bears (Ursus arctos) handled during 90 captures between 1999 and 2001. Induction dosages and times were greater for FR bears than PR bears, a finding consistent with depletion of, or decreased sensitivity to, catecholamines. Free-ranging bears also had higher rectal temperatures 15 min following immobilization and temperatures throughout handling that correlated positively with induction time. Physically restrained bears had higher white blood cell counts, with more neutrophils and fewer lymphocytes and eosinophils, than did FR bears. This white blood cell profile was consistent with a stress leukogram, possibly affected by elevated levels of serum cortisol. Serum concentrations of alanine aminotransferase, aspartate aminotransferase, and creatine kinase were higher in PR bears that suggested muscle injury. Serum concentrations of sodium and chloride also were higher in PR bears and attributed to reduced body water volume through water deprivation and increased insensible water loss. Overall, different methods of capture resulted in different patterns of physiologic disturbance. Reducing pursuit and drug induction times should help to minimize increase in body temperature and alteration of acid-base balance in bears immobilized by remote injection. Minimizing restraint time and ensuring snare-anchoring cables are short should help to minimize loss of body water and prevent serious muscle injury in bears captured by leg-hold snare.

Animals↗