Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Conjunctivitis”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

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

At least 631 records · Page 35Linked to original sources
PubMed1997

Storage of feature conjunctions in transient auditory memory.

The purpose of this study was to determine whether feature conjunctions are stored in transient auditory memory. The mismatch negativity (MMN), an event-related potential that is elicited by stimuli that differ from a series of preceding stimuli, was used in this endeavour. A tone that differed from the preceding series of stimuli in the conjunction of two of its features, both present in preceding stimuli but in different combinations, was found to elicit the MMN. The data are interpreted to indicate that information about the conjunction of features is stored in the memory.

Acoustic Stimulation↗
PubMed2005

Surgical advantages with ITI TE implants placement in conjunction with split crest technique. 18-month results of an ongoing prospective study.

Implant rehabilitation of the edentulous maxilla may be somewhat problematic because of anatomic situations involving insufficient bone thickness. One approach in this situation is localized ridge augmentation with the split crest technique. This surgical approach allows the external cortical plate of the maxilla to be moved in a labial direction to gain an increase in width to introduce implants of appropriate diameter. This ongoing prospective study evaluated: (i) the surgical advantages that the new ITI TE implants have showed compared with the ITI standard solid-screw implants when placed in conjunction with the split crest technique and (ii) the implant success rate associated with 42 ITI TE implants and 40 ITI standard solid-screw implants placed in 40 patients in conjunction with the split crest technique. ITI TE implants have shown direct and indirect advantages in reducing the risk of fracture of the labial cortical plate during all the three fundamental surgical steps of this technique: (a) the ridge expansion with osteotomes; (b) implant site preparation with drills and (c) implant insertion. The overall success rates of ITI TE implants and standard screw implants were 100% and 95%, respectively. Based on the preliminary results of the present study, it can be concluded that ITI TE implants inserted in conjunction with split crest technique seem to be a promising surgical procedure to treat selected anatomic situations involving insufficient maxillary bone thickness.

Adult↗
PubMed1995

Superior parietal cortex activation during spatial attention shifts and visual feature conjunction.

Positron emission tomography was used to measure changes in the regional cerebral blood flow of normal people while they searched visual displays for targets defined by color, by motion, or by a conjunction of color and motion. A region in the superior parietal cortex was activated only during the conjunction task, at a location that had previously been shown to be engaged by successive shifts of spatial attention. Correspondingly, the time needed to detect a conjunction target increased with the number of items in the display, which is consistent with the use of a mechanism that successively analyzes each item in the visual field.

Attention↗
PubMed1997

Prednisolone at anti-inflammatory or immunosuppressive dosages in conjunction with doxycycline does not potentiate the severity of Rickettsia rickettsii infection in dogs.

Dogs were experimentally inoculated with Rickettsia rickettsii to determine if anti-inflammatory or immunosuppressive dosages of prednisolone, when administered in conjunction with an antirickettsial antibiotic (doxycycline), induced therapeutically relevant pathophysiological consequences that ultimately influence disease outcome. Although the duration of rickettsemia was prolonged in dogs receiving immunosuppressive, but not anti-inflammatory, corticosteroids, concurrent administration of doxycycline and corticosteroids conferred no other detected detrimental effects. Treatment with doxycycline or doxycycline in conjunction with prednisolone resulted in decreased R. rickettsii-specific antibody titers; however, examination of appropriately timed acute- and convalescent-phase serum samples would have facilitated an accurate diagnosis of Rocky Mountain spotted fever (RMSF) in all 16 dogs. We conclude that the concurrent use of anti-inflammatory or immunosuppressive doses of prednisolone in conjunction with doxycycline, early in the course of experimental RMSF, confers no clinically relevant detrimental effects and that additional studies might be indicated to detect possible beneficial effects in cases of severe or potentially fulminant RMSF. However, because the illness induced in these dogs was of mild to moderate severity, the results of this study should definitely not be construed as supporting the safety or efficacy of prednisolone for treatment of severe canine or human RMSF.

Animals↗
PubMed1979

Humoral immunity in the resolution of genital infection in female guinea pigs infected with the agent of guinea pig inclusion conjunctivitis.

Female guinea pigs infected in the genital tract with the chlamydial agent of guinea pig inclusion conjunctivitis were selectively immunosuppressed by varying regimens of cyclophosphamide (Cy) treatment. Temporary suppression of both humoral and cell-mediated immunity by daily treatment of Cy (25 mg/kg) for 13 days resulted in a prolonged infection, whereas daily treatment for the duration of the experiment totally prevented the development of humoral and cell-mediated responses and produced an intense and prolonged infection which did not resolve. When humoral immunity alone was suppressed by treatment with Cy (250 and 150 mg/kg) at 9-day intervals, the infection again did not resolve. Treatment with 100 mg of Cy per kg at 9-day intervals resulted in an extended infection which resolved concomitantly with the development of antibody to guinea pig inclusion conjunctivitis. These data indicate that humoral immunity is essential for the recovery of female guinea pigs from guinea pig inclusion conjunctivitis genital infection. A market weight loss was observed which could not be attributed to Cy treatment alone. Edematous and ulcerative changes of the external genitalia were also noted.

Animals↗
PubMed1982

Prophylaxis of neonatal conjunctivitis. An analytic review.

The recommendation by the Centers for Disease Control (CDC) that erythromycin and tetracycline ointments, as well as silver nitrate solution, are acceptable regimens for prophylaxis of gonococcal ophthalmia neonatorum (GON) has resulted in widespread local review of policies for ocular prophylaxis. The data concerning the efficacy and side effects of these agents are somewhat confusing or nonexistent. We discuss the etiologies of neonatal conjunctivitis and the topical and systemic agents used for prophylaxis of GON. We also review all studies that have compared the efficacy of one prophylactic agent with that of another agent or with no prophylaxis. It is found that all three agents have similar efficacy in preventing GON, although silver nitrate has been used more extensively in populations at high risk for GON. However, since Chlamydia trachomatis is the most common infectious cause of neonatal conjunctivitis in the United States at this time, and erythromycin appears to be very effective in prevention of neonatal conjunctivitis due to C. trachomatis, it may have an advantage over the other two agents. In addition, erythromycin use is associated with fewer ocular reactions than is silver nitrate.

Administration, Topical↗
PubMed2005

The composition of category conjunctions.

In three experiments, the authors investigated the impression formation process resulting from the perception of familiar or unfamiliar social category combinations. In Experiment 1, participants were asked to generate attributes associated with either a familiar or unfamiliar social category conjunction. Compared to familiar combinations, the authors found that when the conjunction was unfamiliar, participants formed their impression less from the individual constituent categories and relatively more from novel emergent attributes. In Experiment 2, the authors replicated this effect using alternative experimental materials. In Experiment 3, the effect generalized to additional (orthogonally combined) gender and occupation categories. The implications of these findings for understanding the processes involved in the conjunction of social categories, and the formation of new stereotypes, are discussed.

Adult↗
PubMed1968

Clock-delivered reinforcers in conjunctive and interlocking schedules.

The effects of different temporal requirements in conjunctive and interlocking schedules of reinforcement were examined. The compound schedules were arranged so that a reinforcer could be delivered by either a rat's response or a clock. As the temporal requirements increased in the interlocking schedules, the overall rate of responding increased, but the pattern of responding remained relatively unchanged. As the temporal requirement increased in the conjunctive schedules, the overall rate decreased and a pause-and-run pattern of responding emerged. When the response requirement was reduced to one in the conjunctive schedule for one animal, a low and extremely stable rate of responding developed.

Animals↗
PubMed1990

Treatment of class II furcation defects using porous hydroxylapatite in conjunction with a polytetrafluoroethylene membrane.

The purpose of the present study was to determine whether the use of a porous hydroxylapatite in conjunction with guided tissue regeneration technique influenced the clinical results in the treatment of Class II furcation defects in humans. Fifteen subjects with a mean age of 39.4 +/- 9.3 years were used in this study. All subjects had Class II furcation defects on the buccal surfaces of 2 lower molars. In each subject one furcation defect was filled with granular porous hydroxylapatite and then a barrier of polytetrafluoroethylene periodontal material was positioned over the furcation. The other furca was treated in the same manner except that no hydroxylapatite was used. The flaps were placed coronally to their presurgical level. Before the surgery and 6 months postsurgery all areas were clinically evaluated using the same clinical parameters. Reentry procedures were used to repeat measurements of the osseous defects made during the initial surgery. At 6 months both surgical procedures resulted in statistically significant reduction in pocket depth and gain in probing attachment level with no significant difference between the two surgical procedures. When porous hydroxylapatite was used in conjunction with a polytetrafluoroethylene membrane, however, less gingival recession and more defect fill were obtained. This study suggests that there is a difference in healing of molar furcations when porous hydroxylapatite is used in conjunction with a barrier membrane. The lesions treated with porous hydroxylapatite gain in clinical attachment and horizontal and vertical bone fill, while the lesions treated with membrane only gain probing attachment with less bony fill.

Adult↗
PubMed2006

Inefficient conjunction search made efficient by concurrent spoken delivery of target identity.

Visual search based on a conjunction of two features typically elicits reaction times that increase linearly as a function of the number of distractors, whereas search based on a single feature is essentially unaffected by set size. These and related findings have often been interpreted as evidence of a serial search stage that follows a parallel search stage. However, a wide range of studies has been showing a form of blending of these two processes. For example, when a spoken instruction identifies the conjunction target concurrently with the visual display, the effect of set size is significantly reduced, suggesting that incremental linguistic processing of the first feature adjective and then the second feature adjective may facilitate something approximating a parallel extraction of objects during search for the target. Here, we extend these results to a variety of experimental designs. First, we replicate the result with a mixed-trials design (ruling out potential strategies associated with the blocked design of the original study). Second, in a mixed-trials experiment, the order of adjective types in the spoken query varies randomly across conditions. In a third experiment, we extend the effect to a triple-conjunction search task. A fourth (control) experiment demonstrates that these effects are not due to an efficient odd-one-out search that ignores the linguistic input. This series of experiments, along with attractor-network simulations of the phenomena, provide further evidence toward understanding linguistically mediated influences in real-time visual search processing.

Attention↗
PubMed2006

Cross-trial priming in visual search for singleton conjunction targets: role of repeated target and distractor features.

Kristjánsson, Wang, and Nakayama (2002) demonstrated that visual search for conjunctively defined targets can be substantially expedited ("primed") when target and distractor features are repeated on consecutive trials. Two experiments were conducted to examine whether the search response time (RT) facilitation on target-present trials results from repetition of target-defining features, distractor features, or both. The experiments used a multiple conjunctive search paradigm (adapted from Kristjánsson et al., 2002), in which the target and distractor features were varied (i.e., repeated) independently of each other across successive trials. The RT facilitation was numerically largest when both target and distractor features were repeated, but not significantly larger than that when only distractor features were repeated. This indicates that cross-trial priming effects in conjunctive visual search result mainly from the repetition of distractor, rather than target, features.

Adult↗
PubMed2001

Activation and inhibition of stimulus features in conjunction search.

Two visual search experiments were conducted to examine how activation of target-relevant features and inhibition of target-irrelevant features are involved in conjunction search. The hypothesis was that if an excitatory mechanism is involved, it should be revealed as facilitation when a target and distractors are repeated in two successive displays. If an inhibitory mechanism is involved, suppression should be obtained when distractor features from one display determine the target in the following display. The results of Experiment 1 showed that facilitation was observed consistently across two set sizes (5 and 9), whereas suppression was obtained only with larger set size (9). This pattern of results was replicated and extended in Experiment 2 with different set size. It seems that both excitatory and inhibitory mechanisms are involved in conjunction search. The excitatory mechanism seems to play a role in conjunction search regardless of search difficulty, whereas the inhibitory mechanism might play a role only when set size is larger.

Adult↗
PubMed2004

Categorization influences illusory conjunctions.

Illusory conjunctions (ICs) provide evidence for a binding problem that must be resolved in vision. Objects that are perceptually grouped are more likely to have their features erroneously conjoined. We examined whether semantic grouping, determined by category membership (letter vs. number), also influences illusory conjunction rates. Participants were instructed to detect an "L" or a "7" among briefly presented character strings and to report its color. Despite high shape discrimination accuracy, participants often made color conjunction errors, reporting instead the color of a distractor character, "O". This distractor could be ambiguously interpreted as a letter or a number. The status of the "O" was determined by other noncolored flanker characters, which were either letters or numbers. When both the target and flankers were of the same category, participants made more ICs than when the target and flankers were of different categories. This finding demonstrates that alphanumeric categorization can precede and subsequently influence binding.

Adult↗
PubMed1992

Motion coherence and conjunction search: implications for guided search theory.

Feature integration theory has recently been revised with two proposals that visual conjunction search can be parallel under some circumstances--either because items with nontarget features are inhibited, or because items with target features are excited. We examined whether excitatory or inhibitory guidance controlled conjunction search for an X oscillating in one direction among Os oscillating in that direction and Xs oscillating in another. Search was affected by whether items oscillated in phase with each other, and it was exceptionally difficult when items with target motion moved out of phase with each other and items with nontarget motion moved out of phase. The results suggest that conjunction search can be guided both by excitation of target features and by inhibition of nontarget features.

Adolescent↗
PubMed1998

Parallel coding of conjunctions in visual search.

Two experiments investigated whether the conjunctive nature of nontarget items influenced search for a conjunction target. Each experiment consisted of two conditions. In both conditions, the target item was a red bar tilted to the right, among white tilted bars and vertical red bars. As well as color and orientation, display items also differed in terms of size. Size was irrelevant to search in that the size of the target varied randomly from trial to trial. In one condition, the size of items correlated with the other attributes of display items (e.g., all red items were big and all white items were small). In the other condition, the size of items varied randomly (i.e., some red items were small and some were big, and some white items were big and some were small). Search was more efficient in the size-correlated condition, consistent with the parallel coding of conjunctions in visual search.

Adult↗
PubMed1990

Detecting conjunctions of color and form in parallel.

Certain theories of visual attention assume that at least one processing stage must be serial when the target of search is defined as the conjunction of two or more separable features. To explain why conjunction-search response times do not always form linearly increasing functions of display size, recent versions of this general model have posited the existence of an early parallel process that guides the serial stage toward display elements that are likely targets. Other models have relaxed the seriality assumption, allowing for a limited number of parallel decisions. In the three experiments reported here, a redundant-target detection task was used with conjunctively defined targets and display sizes of two (Experiment 1), one or two (Experiment 2), and six (Experiment 3). In all three experiments, strong evidence for parallel processing was observed. The implications for models of elementary visual processes are discussed.

Attention↗
PubMed1992

Memory-conjunction errors: miscombination of stored stimulus features can produce illusions of memory.

We demonstrate that subjects will often claim to have previously seen a new stimulus if they have previously seen stimuli containing its component features. Memory for studied stimuli was measured using a "yes"/"no" recognition test. There were three types of test stimuli: target stimuli, which had been presented during study, conjunction stimuli, constructed by combining the features of separate study stimuli, and feature stimuli, in which studied stimulus features were combined with new, unstudied, features. For both nonsense words and faces, the subjects made many more false alarms for conjunction than for feature stimuli. Additional experiments demonstrated that the results were not due to physical similarity between study and test stimuli and that conjunction errors were much more common than feature errors in recall. The results demonstrate that features of stored stimuli maintain some independence in memory and can be incorrectly combined to produce recognition errors.

Humans↗
PubMed1993

Efficiency of visual selection in duplex and conjunction conditions in partial report.

Factors that determine the efficiency of visual selection were investigated in two precued partial-report experiments. There were four selection conditions: a color condition (e.g., selecting purple letters among blue letters), a class condition (e.g., selecting letters among digits), a duplex condition (e.g., selecting purple letters among blue digits; that is, the targets differed from the distractors both in color and in alphanumeric class), and a conjunction condition (e.g., selecting purple letters among blue letters and purple digits; that is, the targets differed from the distractors either in color or in alphanumeric class). The efficiency of visual selection was highest in the duplex condition and lowest in the conjunction condition. The difference in performance across the different selection conditions within subjects was accounted for by variation in the value of a single parameter of the fixed-capacity independent race model (FIRM) proposed by Shibuya and Bundesen (1988), which assumes independent parallel processing, limitations in both processing capacity and storage capacity, and time-invariant selectivity. By assuming that the factors that determine the efficiency of selection in the color and class conditions also underlie the efficiency of selection in the duplex and conjunction conditions, an extension of FIRM, FIRM+, accounted for the relationship with respect to efficiency of selection among the different conditions.

Adolescent↗