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Find video protocols related to scientific articles indexed in Pubmed.
Intraocular pressure rise is predictive of vision improvement after intravitreal triamcinolone acetonide for diabetic macular oedema: a retrospective analysis of data from a randomised controlled trial.
BMC Ophthalmol
PUBLISHED: 09-25-2014
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Intravitreal triamcinolone acetonide (IVTA) is an effective treatment for recalcitrant diabetic macular oedema (DMO). It has been shown to improve vision with benefits persisting up to five years. The most common initial side effect of IVTA treatment is rise in intraocular pressure, occurring in approximately 50% of patients within the first 6 months of treatment. We evaluated whether there is a correlation between the development of intraocular pressure rise and improvement in vision.
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Outcomes of persistently active neovascular age-related macular degeneration treated with VEGF inhibitors: observational study data.
Br J Ophthalmol
PUBLISHED: 09-25-2014
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To describe outcomes of eyes with wet age-related macular degeneration (AMD) subdivided by lesion activity in a large multicentre cohort study.
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Getting to compliance in forced exercise in rodents: a critical standard to evaluate exercise impact in aging-related disorders and disease.
J Vis Exp
PUBLISHED: 08-22-2014
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There is a major increase in the awareness of the positive impact of exercise on improving several disease states with neurobiological basis; these include improving cognitive function and physical performance. As a result, there is an increase in the number of animal studies employing exercise. It is argued that one intrinsic value of forced exercise is that the investigator has control over the factors that can influence the impact of exercise on behavioral outcomes, notably exercise frequency, duration, and intensity of the exercise regimen. However, compliance in forced exercise regimens may be an issue, particularly if potential confounds of employing foot-shock are to be avoided. It is also important to consider that since most cognitive and locomotor impairments strike in the aged individual, determining impact of exercise on these impairments should consider using aged rodents with a highest possible level of compliance to ensure minimal need for test subjects. Here, the pertinent steps and considerations necessary to achieve nearly 100% compliance to treadmill exercise in an aged rodent model will be presented and discussed. Notwithstanding the particular exercise regimen being employed by the investigator, our protocol should be of use to investigators that are particularly interested in the potential impact of forced exercise on aging-related impairments, including aging-related Parkinsonism and Parkinson's disease.
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The Effects of Anodal Stimulation of the Left Prefrontal Cortex on Sentence Production.
Brain Stimul
PUBLISHED: 07-23-2014
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Most studies in which Anodal Transcranial Direct Current Stimulation (A-tDCS) has been used to improve language production have focused on single words. Yet sentence production requires more than lexical retrieval. For example, successful suppression of the past and careful planning of the future are two critical requirements for producing a correct sentence. Can A-tDCS improves those, and by extension, production at the sentence level?
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A Structured End-of-Life Curriculum for Neonatal-Perinatal Postdoctoral Fellows.
Am J Hosp Palliat Care
PUBLISHED: 04-19-2014
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Death in tertiary care neonatal intensive care units is a common occurrence. Despite recent advances in pediatric palliative education, evidence indicates that physicians are poorly prepared to care for dying infants and their families. Numerous organizations recommend increased training in palliative and end-of-life care for pediatric physicians. The purpose of this study is to develop a structured end-of-life curriculum for neonatal-perinatal postdoctoral fellows based on previously established principles and curricular guidelines on end-of-life care in the pediatric setting. Results demonstrate statistically significant curriculum effectiveness in increasing fellow knowledge regarding patient qualification for comfort care and withdrawal of support (P = .03). Although not statistically significant, results suggest the curriculum may have improved fellows' knowledge of appropriate end-of-life medical management, comfort with addressing the family, and patient pain assessment and control.
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Efficient capture of high-quality data on outcomes of treatment for macular diseases: the fight retinal blindness! Project.
Retina (Philadelphia, Pa.)
PUBLISHED: 04-17-2014
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To describe the development of a web-based high-quality data collection tool to track the outcomes of treatment of macular disease in routine practice.
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Multisite longitudinal reliability of tract-based spatial statistics in diffusion tensor imaging of healthy elderly subjects.
Neuroimage
PUBLISHED: 02-19-2014
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Large-scale longitudinal neuroimaging studies with diffusion imaging techniques are necessary to test and validate models of white matter neurophysiological processes that change in time, both in healthy and diseased brains. The predictive power of such longitudinal models will always be limited by the reproducibility of repeated measures acquired during different sessions. At present, there is limited quantitative knowledge about the across-session reproducibility of standard diffusion metrics in 3T multi-centric studies on subjects in stable conditions, in particular when using tract based spatial statistics and with elderly people. In this study we implemented a multi-site brain diffusion protocol in 10 clinical 3T MRI sites distributed across 4 countries in Europe (Italy, Germany, France and Greece) using vendor provided sequences from Siemens (Allegra, Trio Tim, Verio, Skyra, Biograph mMR), Philips (Achieva) and GE (HDxt) scanners. We acquired DTI data (2 × 2 × 2 mm(3), b = 700 s/mm(2), 5 b0 and 30 diffusion weighted volumes) of a group of healthy stable elderly subjects (5 subjects per site) in two separate sessions at least a week apart. For each subject and session four scalar diffusion metrics were considered: fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD) and axial (AD) diffusivity. The diffusion metrics from multiple subjects and sessions at each site were aligned to their common white matter skeleton using tract-based spatial statistics. The reproducibility at each MRI site was examined by looking at group averages of absolute changes relative to the mean (%) on various parameters: i) reproducibility of the signal-to-noise ratio (SNR) of the b0 images in centrum semiovale, ii) full brain test-retest differences of the diffusion metric maps on the white matter skeleton, iii) reproducibility of the diffusion metrics on atlas-based white matter ROIs on the white matter skeleton. Despite the differences of MRI scanner configurations across sites (vendors, models, RF coils and acquisition sequences) we found good and consistent test-retest reproducibility. White matter b0 SNR reproducibility was on average 7 ± 1% with no significant MRI site effects. Whole brain analysis resulted in no significant test-retest differences at any of the sites with any of the DTI metrics. The atlas-based ROI analysis showed that the mean reproducibility errors largely remained in the 2-4% range for FA and AD and 2-6% for MD and RD, averaged across ROIs. Our results show reproducibility values comparable to those reported in studies using a smaller number of MRI scanners, slightly different DTI protocols and mostly younger populations. We therefore show that the acquisition and analysis protocols used are appropriate for multi-site experimental scenarios.
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The road to understanding is paved with the speaker's intentions: cues to the speaker's attention and intentions affect pronoun comprehension.
Cogn Psychol
PUBLISHED: 02-15-2014
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A series of experiments explore the effects of attention-directing cues on pronoun resolution, contrasting four specific hypotheses about the interpretation of ambiguous pronouns he and she: (1) it is driven by grammatical rules, (2) it is primarily a function of social processing of the speaker's intention to communicate, (3) it is modulated by the listener's own egocentric attention, and (4) it is primarily a function of learned probabilistic cues. Experiment 1 demonstrates that pronoun interpretation is guided by the well-known N1 (first-mention) bias, which is also modulated by both the speaker's gaze and pointing gestures. Experiment 2 demonstrates that a low-level visual capture cue has no effect on pronoun interpretation, in contrast with the social cue of pointing. Experiment 3 uses a novel intentional cue: the same attention-capture flash as in Experiment 2, but with instructions that the cue is intentionally created by the speaker. This cue does modulate the N1 bias, demonstrating the importance of information about the speaker's intentions to pronoun resolution. Taken in sum, these findings demonstrate that pronoun resolution is a process best categorized as driven by an appreciation of the speaker's communicative intent, which may be subserved by a sensitivity to predictive cues in the environment.
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The effects of mGluR2/3 activation on acute and repeated amphetamine-induced locomotor activity in differentially reared male rats.
Exp Clin Psychopharmacol
PUBLISHED: 01-27-2014
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Environmental stimuli play a key role in affecting the likelihood to abuse drugs. Environmental enrichment can reduce that likelihood. The neurotransmitter glutamate contributes to both drug reward and rearing-induced changes in the brain. The current study investigated the effects of the Group-2 metabotropic glutamate receptor (mGluR2/3) agonist, LY-379268 (0.5, 1.0 mg/kg), on acute and repeated amphetamine-induced locomotor activity in differentially reared male rats. Male Sprague-Dawley rats were randomly assigned to one of 3 environmental conditions postweaning: enriched (EC), isolated (IC), or standard (SC), where they reared for 30 days. The effect of LY-379268 on acute amphetamine-induced locomotor activity was assessed. Rats were injected with either LY-379268 (0.5, 1.0 mg/kg) or saline prior to an amphetamine (0.5 mg/kg) or saline challenge injection. Rats were also administered amphetamine (0.5 mg/kg) or saline injections prior to 5 locomotor sessions. Following a rest period of 14-15 days, the effects of repeated amphetamine exposure were evaluated using LY-379268 (0.5, 1.0 mg/kg) or saline injections 30 min prior to receiving amphetamine (0.5 mg/kg). Results showed that LY-379268 administration dose-dependently attenuated acute amphetamine-induced locomotor activity, with EC rats generally displaying less attenuation than IC or SC rats. After repeated amphetamine administrations, the ability of LY-379268 to attenuate the final expression of amphetamine-induced locomotor activity in differentially reared rats was dose-dependent. The differing effect of LY-379268 observed in EC rats suggests enrichment-induced glutamatergic alterations that may protect against sensitivity to psychostimulants.
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Are Morphometrics Sufficient for Estimating Age of Pre-Fledging Birds in the Field? A Test Using Common Terns (Sterna hirundo).
PLoS ONE
PUBLISHED: 01-01-2014
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Age is a key component of fitness, affecting survival and reproductive capacities. Where it is not possible to study known individuals from birth, morphometrics (predominantly patterns of plumage development for birds) are most often used to estimate age. Although criteria for age estimations exist for many species, the degree to which these criteria improve the precision of estimates remains to be tested, restricting their widespread acceptance. We develop a photographic tool for estimating ages of Common Tern (Sterna hirundo) chicks and test it using 100 human observers of varying prior experience across four breeding colonies (three North American sites and one European site) and under controlled laboratory conditions. We followed the design approach of other morphometric tools, expanding it to create a user-friendly guide (divided into six age groupings). The majority (86%) of observers improved in chick-aging accuracy when using the tool by an average of 20.1% (±1.4 SE) and correctly estimated 60.3% (±1.4) of chick ages. This was similar to the intrinsic aging ability of our best field observer (63.3%). Observers with limited experience showed the greatest increases in chick-aging accuracy over experienced observers who likely had established a method for estimating chick ages prior to using the tool. Even the best observers only correctly estimated ages of chicks 62.9% (±2.8) of the time in the field and 84.0% (±2.9) of the time in the lab when using the tool and typically underestimated ages. This indicates that developmental variation between individual chicks can prevent completely reliable age estimates and corroborates the few existing data that suggest that morphometric criteria fail to achieve robust levels of accuracy and may introduce error into studies that rely on them. We conclude that novel approaches for estimating age, not only morphometric criteria, must be pursued.
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Ceftriaxone increases glutamate uptake and reduces striatal tyrosine hydroxylase loss in 6-OHDA Parkinsons model.
Mol. Neurobiol.
PUBLISHED: 09-06-2013
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Excess glutamatergic neurotransmission may contribute to excitotoxic loss of nigrostriatal neurons in Parkinsons disease (PD). Here, we determined if increasing glutamate uptake could reduce the extent of tyrosine hydroxylase (TH) loss in PD progression. The beta-lactam antibiotic, ceftriaxone, increases the expression of glutamate transporter 1 (GLT-1), a glutamate transporter that plays a major role in glutamate clearance in central nervous system and may attenuate adverse behavioral or neurobiological function in other neurodegenerative disease models. In association with >80 % TH loss, we observed a significant decrease in glutamate uptake in the established 6-hydroxydopamine (6-OHDA) PD model. Ceftriaxone (200 mg/kg, i.p.) increased striatal glutamate uptake with >5 consecutive days of injection in nonlesioned rats and lasted out to 14 days postinjection, a time beyond that required for 6-OHDA to produce >70 % TH loss (?9 days). When ceftriaxone was given at the time of 6-OHDA, TH loss was ?57 % compared to ?85 % in temporally matched vehicle-injected controls and amphetamine-induced rotation was reduced about 2-fold. This attenuation of TH loss was associated with increased glutamate uptake, increased GLT-1 expression, and reduced Serine 19 TH phosphorylation, a calcium-dependent target specific for nigrostriatal neurons. These results reveal that glutamate uptake can be targeted in a PD model, decrease the rate of TH loss in a calcium-dependent manner, and attenuate locomotor behavior associated with 6-OHDA lesion. Given that detection of reliable PD markers will eventually be employed in susceptible populations, our results give credence to the possibility that increasing glutamate uptake may prolong the time period before locomotor impairment occurs.
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Comparison of Outcomes from a Phase 3 Study of Age-Related Macular Degeneration with a Matched, Observational Cohort.
Ophthalmology
PUBLISHED: 07-11-2013
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To compare outcomes of intravitreal therapy from an observational study cohort with those of participants receiving treatment in the Minimally Classic/Occult Trial of the Anti-VEGF Antibody Ranibizumab (MARINA) for the treatment of neovascular age-related macular degeneration (wet AMD).
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Prospective audit of exudative age-related macular degeneration: 12-month outcomes in treatment-naive eyes.
Invest. Ophthalmol. Vis. Sci.
PUBLISHED: 07-04-2013
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We report the 12-month outcomes of 1140 treatment-naïve eyes with exudative age-related macular degeneration (wet AMD) who were treated for 12 months with intravitreal anti-VEGF drugs in routine clinical practice.
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Humility in medicine.
Clin. Dermatol.
PUBLISHED: 04-24-2013
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Becoming a physician comes with privilege and exciting opportunities. The rigor of academic medicine can be challenging. The ability to have humility as a physician is not only a sign of a good doctor, but it can be one of the most challenging attributes to maintain. My surgeon, Dr. Steven Kopits, embodied what it means to be a humble, yet accomplished physician.
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Brain morphometry reproducibility in multi-center 3T MRI studies: a comparison of cross-sectional and longitudinal segmentations.
Neuroimage
PUBLISHED: 03-25-2013
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Large-scale longitudinal multi-site MRI brain morphometry studies are becoming increasingly crucial to characterize both normal and clinical population groups using fully automated segmentation tools. The test-retest reproducibility of morphometry data acquired across multiple scanning sessions, and for different MR vendors, is an important reliability indicator since it defines the sensitivity of a protocol to detect longitudinal effects in a consortium. There is very limited knowledge about how across-session reliability of morphometry estimates might be affected by different 3T MRI systems. Moreover, there is a need for optimal acquisition and analysis protocols in order to reduce sample sizes. A recent study has shown that the longitudinal FreeSurfer segmentation offers improved within session test-retest reproducibility relative to the cross-sectional segmentation at one 3T site using a nonstandard multi-echo MPRAGE sequence. In this study we implement a multi-site 3T MRI morphometry protocol based on vendor provided T1 structural sequences from different vendors (3D MPRAGE on Siemens and Philips, 3D IR-SPGR on GE) implemented in 8 sites located in 4 European countries. The protocols used mild acceleration factors (1.5-2) when possible. We acquired across-session test-retest structural data of a group of healthy elderly subjects (5 subjects per site) and compared the across-session reproducibility of two full-brain automated segmentation methods based on either longitudinal or cross-sectional FreeSurfer processing. The segmentations include cortical thickness, intracranial, ventricle and subcortical volumes. Reproducibility is evaluated as absolute changes relative to the mean (%), Dice coefficient for volume overlap and intraclass correlation coefficients across two sessions. We found that this acquisition and analysis protocol gives comparable reproducibility results to previous studies that used longer acquisitions without acceleration. We also show that the longitudinal processing is systematically more reliable across sites regardless of MRI system differences. The reproducibility errors of the longitudinal segmentations are on average approximately half of those obtained with the cross sectional analysis for all volume segmentations and for entorhinal cortical thickness. No significant differences in reliability are found between the segmentation methods for the other cortical thickness estimates. The average of two MPRAGE volumes acquired within each test-retest session did not systematically improve the across-session reproducibility of morphometry estimates. Our results extend those from previous studies that showed improved reliability of the longitudinal analysis at single sites and/or with non-standard acquisition methods. The multi-site acquisition and analysis protocol presented here is promising for clinical applications since it allows for smaller sample sizes per MRI site or shorter trials in studies evaluating the role of potential biomarkers to predict disease progression or treatment effects.
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Signals from the brainstem sleep/wake centers regulate behavioral timing via the circadian clock.
PLoS ONE
PUBLISHED: 01-01-2013
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Sleep-wake cycling is controlled by the complex interplay between two brain systems, one which controls vigilance state, regulating the transition between sleep and wake, and the other circadian, which communicates time-of-day. Together, they align sleep appropriately with energetic need and the day-night cycle. Neural circuits connect brain stem sites that regulate vigilance state with the suprachiasmatic nucleus (SCN), the master circadian clock, but the function of these connections has been unknown. Coupling discrete stimulation of pontine nuclei controlling vigilance state with analytical chemical measurements of intra-SCN microdialysates in mouse, we found significant neurotransmitter release at the SCN and, concomitantly, resetting of behavioral circadian rhythms. Depending upon stimulus conditions and time-of-day, SCN acetylcholine and/or glutamate levels were augmented and generated shifts of behavioral rhythms. These results establish modes of neurochemical communication from brain regions controlling vigilance state to the central circadian clock, with behavioral consequences. They suggest a basis for dynamic integration across brain systems that regulate vigilance states, and a potential vulnerability to altered communication in sleep disorders.
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Baseline central macular thickness predicts the need for retreatment with intravitreal triamcinolone plus laser photocoagulation for diabetic macular edema.
Clin Ophthalmol
PUBLISHED: 01-01-2013
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To identify baseline characteristics that predict the number of treatments with intravitreal triamcinolone acetonide (IVTA) plus laser photocoagulation needed to treat diabetic macular edema over a 2-year period.
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Impact of mGluR5 during amphetamine-induced hyperactivity and conditioned hyperactivity in differentially reared rats.
Psychopharmacology (Berl.)
PUBLISHED: 05-31-2011
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3-((2-Methyl-1,3-thiazol-4-yl)ethynyl)pyridine hydrochloride (MTEP) is a metabotropic glutamate receptor 5 (mGluR5) antagonist that may alter drug sensitivity in differentially reared rats due to its involvement in the psychostimulant reward pathway and plasticity.
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How mood challenges emotional memory formation: an fMRI investigation.
Neuroimage
PUBLISHED: 02-17-2011
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Experimental mood manipulations and functional magnetic resonance imaging (fMRI) provide a unique opportunity for examining the neural correlates of mood-congruent memory formation. While prior studies in mood-disorder patients point to the medial temporal lobe in the genesis of mood-congruent memory (MCM) bias, the interaction between mood and emotional memory formation has not been investigated in healthy participants. In particular it remains unclear how regulatory structures in the pre-frontal cortex may be involved in mediating this phenomenon. In this study, event-related fMRI was performed on 20 healthy participants using a full-factorial, within-subjects repeated-measures design to examine how happy and sad moods impact memory for valenced stimuli (positive, negative and neutral words). Main effects of mood, stimulus valence and memory were examined as was activity related to successful memory formation during congruent and in-congruent moods. Behavioral results confirm an MCM bias while imaging results show amygdala and hippocampal engagement in a global mood and successful recall, respectively. MCM formation was characterized by increased activity during mood-congruent encoding of negative words in the orbito-frontal cortex (OFC) and for mood-incongruent processing of negative words in medial- and inferior-frontal gyri (MFG/IFG). These findings indicate that different pre-frontal regions facilitate mood-congruent and incongruent encoding of successfully recalled negative words at the time of learning, with OFC enhancing congruency and the left IFG and MFG helping overcome semantic incongruities between mood and stimulus valence.
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Rose or black-coloured glasses? Altered neural processing of positive events during memory formation is a trait marker of depression.
J Affect Disord
PUBLISHED: 01-21-2011
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Valence-specific memory enhancement is one of the core cognitive functions that causes and maintains Major Depressive Disorder (MDD). While previous neuroimaging studies have elucidated the neural underpinnings of this emotional enhancement effect in depressed patients, this study aimed at detecting processing biases that are maintained throughout remission while patients were euthymic.
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Intravitreal triamcinolone prior to laser treatment of diabetic macular edema: 24-month results of a randomized controlled trial.
Ophthalmology
PUBLISHED: 01-12-2011
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To report the 24 months outcomes from a clinical trial of intravitreal triamcinolone acetonide (IVTA) plus laser versus laser treatment only in eyes with diabetic macular edema (DME).
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Evolution of reticular pseudodrusen.
Br J Ophthalmol
PUBLISHED: 11-25-2010
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To report observations relating to the clinical recognition and possible basis of reticular pseudodrusen (RPD).
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Lack of association of a spontaneous mutation of the Chrm2 gene with behavioral and physiologic phenotypic differences in inbred mice.
Comp. Med.
PUBLISHED: 09-08-2010
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The nucleotide substitution C797T in the Chrm2 gene causes substitution of leucine for proline at position 266 (P266L) of the CHRM2 protein. Because Chrm2 codes for the type 2 muscarinic receptor, this mutation could influence physiologic and behavioral phenotypes of mice. Chrm2 mRNA was not differentially expressed in 2 brain regions with high cholinergic innervation in a mouse strain that does (BALB/cByJ) or does not (C57BL/6J) have the mutation. In addition, strains of mice with and without the C797T point mutation in Chrm2 did not differ significantly in muscarinic binding properties. Variation across strains was detected in terms of acoustic startle, prepulse inhibition, and the physiologic effects of the muscarinic agonist oxotremorine. However, interstrain differences in these measures did not correlate with the presence of the mutation. Although we were unable to associate a measurable phenotype with the Chrm2 mutation, assessment of the mutation on other genetic backgrounds or in the context of other traits might reveal differential effects. Therefore, despite our negative findings, evaluation of characteristics that involve muscarinic function should be undertaken with caution when comparing mice with different alleles of the Chrm2 gene.
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Pretreatment with intravitreal triamcinolone before laser for diabetic macular edema: 6-month results of a randomized, placebo-controlled trial.
Invest. Ophthalmol. Vis. Sci.
PUBLISHED: 12-17-2009
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To determine whether pretreatment with intravitreal triamcinolone acetonide (IVTA) before laser photocoagulation is effective in eyes with diabetic macular edema (DME).
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Reference production in young speakers with and without autism: effects of discourse status and processing constraints.
Cognition
PUBLISHED: 04-11-2009
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We examine the referential choices (pronouns/zeros vs. names/descriptions) made during a narrative by high-functioning children and adolescents with autism and a well-matched typically developing control group. The process of choosing appropriate referring expressions has been proposed to depend on two areas of cognitive functioning: (a) judging the attention and knowledge of ones interlocutor, and (b) the use of memory and attention mechanisms to represent the discourse situation. We predicted possible group differences, since autism is often associated with deficits in (a) mentalizing and (b) memory and attention, as well as a more general tendency to have difficulty with the pragmatic aspects of language use. Results revealed that some of the participants with autism were significantly less likely to produce pronouns or zeros in some discourse contexts. However, the difference was only one of degree. Overall, all participants in our analysis exhibited fine-grained sensitivity to the discourse context. Furthermore, referential choices for all participants were modulated by factors related to the cognitive effort of language production.
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Fronto-limbic microstructure and structural connectivity in remission from major depression.
Psychiatry Res
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Previous research has suggested that abnormalities within the amygdala and prefrontal cortex (PFC) may underlie major depressive disorder (MDD). The contribution of microstructural alterations within these regions in adult MDD is still equivocal. Therefore, seventeen middle-aged medication-free remitted MDD patients and 21 matched never-depressed control subjects underwent structural magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI). Despite comparable amygdala volumes, remitted MDD patients revealed decreased mean diffusivity (MD) and increased fractional anisotropy (FA) within the left amygdala, which may be interpreted as greater cell density and increased number of fibers, respectively. This last notion was supported by probabilistic tractography results, which revealed increased connectivity from the left amygdala to the hippocampus, the cerebellum and the brain stem. Further, altered microstructure as indicated by increased MD possibly reflecting decreased cell density within the medial PFC (mPFC) was found. Taken together, the current DTI study shows that abnormal microstructure and connectivity of the amygdala and mPFC might be key factors in the pathophysiology of MDD that may account for functional changes.
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Risk of age-related macular degeneration 3 years after cataract surgery: paired eye comparisons.
Ophthalmology
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To clarify possible associations between cataract surgery and progression of age-related macular degeneration (AMD).
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Recruitment of community pharmacies in a randomized trial to generate patient referrals to the tobacco quitline.
Res Social Adm Pharm
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Community pharmacies have the potential to reduce the prevalence of tobacco use, yet most pharmacies do not integrate cessation activities into routine practice.
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Direct impacts of climatic warming on heat stress in endothermic species: seabirds as bioindicators of changing thermoregulatory constraints.
Integr Zool
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There is now abundant evidence that contemporary climatic change has indirectly affected a wide-range of species by changing trophic interactions, competition, epidemiology and habitat. However, direct physiological impacts of changing climates are rarely reported for endothermic species, despite being commonly reported for ectotherms. We review the evidence for changing physiological constraints on endothermic vertebrates at high temperatures, integrating theoretical and empirical perspectives on the morphology, physiology and behavior of marine birds. Potential for increasing heat stress exposure depends on changes in multiple environmental variables, not just air temperature, as well as organism-specific morphology, physiology and behavior. Endotherms breeding at high latitudes are vulnerable to the forecast, extensive temperature changes because of the adaptations they possess to minimize heat loss. Low-latitude species will also be challenged as they currently live close to their thermal limits and will likely suffer future water shortages. Small, highly-active species, particularly aerial foragers, are acutely vulnerable as they are least able to dissipate heat at high temperatures. Overall, direct physiological impacts of climatic change appear underrepresented in the published literature, but available data suggest they have much potential to shape behavior, morphology and distribution of endothermic species. Coincidence between future heat stress events and other energetic constraints on endotherms remains largely unexplored but will be key in determining the physiological impacts of climatic change. Multi-scale, biophysical modeling, informed by experiments that quantify thermoregulatory responses of endotherms to heat stress, is an essential precursor to urgently-needed analyses at the population or species level.
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Audience design affects acoustic reduction via production facilitation.
Psychon Bull Rev
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In this article, we examine the hypothesis that acoustic variation (e.g., reduced vs. prominent forms) results from audience design. Bard et al. (Journal of Memory and Language 42:1-22, 2000) have argued that acoustic prominence is unaffected by the speakers estimate of addressee knowledge, using paradigms that contrast speaker and addressee knowledge. This question was tested in a novel paradigm, focusing on the effects of addressees feedback about their understanding of the speakers intended message. Speakers gave instructions to addressees about where to place objects (e.g., the teapot goes on red). The addressee either anticipated the object, by picking it up before the instruction, or waited for the instruction. For anticipating addressees, speakers began speaking more quickly and pronounced the word the with shorter duration, demonstrating effects of audience design. However, no effects appeared on the head noun (e.g., teapot), as measured by duration, amplitude, and perceived intelligibility. These results are consistent with a mechanism in which evidence about addressee understanding facilitates production processes, as opposed to triggering particular acoustic forms.
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Transient striatal GLT-1 blockade increases EAAC1 expression, glutamate reuptake, and decreases tyrosine hydroxylase phosphorylation at ser(19).
Exp. Neurol.
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Three glutamate transporters, GLT-1, GLAST, and EAAC1, are expressed in striatum. GLT-1 and, to a lesser extent, GLAST are thought to play a primary role in glutamate reuptake and mitigate excitoxicity. Progressive tyrosine hydroxylase (TH) loss seen in Parkinsons disease (PD) is associated with increased extracellular glutamate. Glutamate receptor antagonists reduce nigrostriatal loss in PD models. These observations suggest that excess synaptic glutamate contributes to nigrostriatal neuron loss seen in PD. Decreased GLT-1 expression occurs in neurodegenerative disease and PD models, suggesting decreased GLT-1-mediated glutamate reuptake contributes to excitotoxicity. To determine how transient GLT-1 blockade affects glutamate reuptake dynamics and a Ca(2+)-dependent process in nigrostriatal terminals, ser(19) phosphorylation of TH, the GLT-1 inhibitor dihydrokainic acid (DHK) was delivered unilaterally to striatum in vivo and glutamate reuptake was quantified ex vivo in crude synaptosomes 3h later. Ca(2+)-influx is associated with excitotoxic conditions. The phosphorylation of TH at ser(19) is Ca(2+)-dependent, and a change resulting from GLT-1 blockade may signify the potential for excitotoxicity to nigrostriatal neurons. Synaptosomes from DHK infused striatum had a 43% increase in glutamate reuptake in conjunction with decreased ser(19) TH phosphorylation. Using a novel GLAST inhibitor and DHK, we determined that the GLAST-mediated component of increased glutamate reuptake increased 3-fold with no change in GLAST or GLT-1 protein expression. However, GLT-1 blockade increased EAAC1 protein expression ~20%. Taken together, these results suggest that GLT-1 blockade produces a transient increase in GLAST-mediated reuptake and EAAC1 expression coupled with reduced ser(19) TH phosphorylation. These responses could represent an endogenous defense against excitotoxicity to the nigrostriatal pathway.
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What is Visualize?

JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

How does it work?

We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

Video X seems to be unrelated to Abstract Y...

In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.