181 research outputs found
Aortic valve and aortic arch pathology after coarctation repair
OBJECTIVE: To investigate the incidence of clinical problems related to a bicuspid valve (aortic stenosis and regurgitation) and the incidence of ascending aorta and aortic arch pathology in combination with coarctation repair. PATIENTS: 124 adult patients after surgical correction of aortic coarctation were studied. The incidence of aortic valve, ascending aorta, and aortic arch pathology was determined using echocardiography and magnetic resonance imaging. The median age at coarctation repair was 9 years and at last follow up 28 years. RESULTS: Three patients died from aorta pathology. Aortic valve disease was found in 63% of the patients, requiring an intervention in 22%, at a median of 13 years after coarctation repair. Ascending aorta dilatation was observed in 28% and aortic arch abnormalities in 23%, among whom kinking of the aortic arch was found in 12%. Antihypertensive medication was used in 24%. In the patients with hypertension the age at operation and age at follow up were significantly higher (p = 0.0001 and p < 0.0001, respectively). CONCLUSION: In addition to the well known problems of hypertension and recoarctation, aortic valve and aortic arch pathology are commonly encountered in patients with previous coarctation repair. Aortic abnormalities may predispose to dilatation and dissection, thus necessitating careful lifelong attention in all patients with coarctation
Timescales of Massive Human Entrainment
The past two decades have seen an upsurge of interest in the collective
behaviors of complex systems composed of many agents entrained to each other
and to external events. In this paper, we extend concepts of entrainment to the
dynamics of human collective attention. We conducted a detailed investigation
of the unfolding of human entrainment - as expressed by the content and
patterns of hundreds of thousands of messages on Twitter - during the 2012 US
presidential debates. By time locking these data sources, we quantify the
impact of the unfolding debate on human attention. We show that collective
social behavior covaries second-by-second to the interactional dynamics of the
debates: A candidate speaking induces rapid increases in mentions of his name
on social media and decreases in mentions of the other candidate. Moreover,
interruptions by an interlocutor increase the attention received. We also
highlight a distinct time scale for the impact of salient moments in the
debate: Mentions in social media start within 5-10 seconds after the moment;
peak at approximately one minute; and slowly decay in a consistent fashion
across well-known events during the debates. Finally, we show that public
attention after an initial burst slowly decays through the course of the
debates. Thus we demonstrate that large-scale human entrainment may hold across
a number of distinct scales, in an exquisitely time-locked fashion. The methods
and results pave the way for careful study of the dynamics and mechanisms of
large-scale human entrainment.Comment: 20 pages, 7 figures, 6 tables, 4 supplementary figures. 2nd version
revised according to peer reviewers' comments: more detailed explanation of
the methods, and grounding of the hypothese
Predicting outcome in children with dilated cardiomyopathy:the use of repeated measurements of risk factors for outcome
Aims We aimed to determine whether in children with dilated cardiomyopathy repeated measurement of known risk factors for death or heart transplantation (HTx) during disease progression can identify children at the highest risk for adverse outcome. Methods and results Of 137 children we included in a prospective cohort, 36 (26%) reached the study endpoint (SE: all-cause death or HTx), 15 (11%) died at a median of 0.09 years [inter-quartile range (IQR) 0.03-0.7] after diagnosis, and 21 (15%) underwent HTx at a median of 2.9 years [IQR 0.8-6.1] after diagnosis. Median follow-up was 2.1 years [IQR 0.8-4.3]. Twenty-three children recovered at a median of 0.6 years [IQR 0.5-1.4] after diagnosis, and 78 children had ongoing disease at the end of the study. Children who reached the SE could be distinguished from those who did not, based on the temporal evolution of four risk factors: stunting of length growth (-0.42 vs. -0.02 length Z-score per year, P 6 years at presentation (all P < 0.001) were predictive of adverse outcome. In multivariate analysis, NT-proBNP appeared the only independent predictor for adverse outcome, a two-fold higher NT-proBNP was associated with a 2.8 times higher risk of the SE (hazard ratio 2.78, 95% confidence interval 1.81-3.94, P < 0.001). Conclusions The evolution over time of NT-proBNP, LVIDd, length growth, and NYU PHFI identified a subgroup of children with dilated cardiomyopathy at high risk for adverse outcome. In this sample, with a limited number of endpoints, NT-proBNP was the strongest independent predictor for adverse outcome
Neuromagnetic Evidence for Early Auditory Restoration of Fundamental Pitch
Background: Understanding the time course of how listeners reconstruct a missing fundamental component in an auditory stimulus remains elusive. We report MEG evidence that the missing fundamental component of a complex auditory stimulus is recovered in auditory cortex within 100 ms post stimulus onset. Methodology: Two outside tones of four-tone complex stimuli were held constant (1200 Hz and 2400 Hz), while two inside tones were systematically modulated (between 1300 Hz and 2300 Hz), such that the restored fundamental (also knows as ββvirtual pitchββ) changed from 100 Hz to 600 Hz. Constructing the auditory stimuli in this manner controls for a number of spectral properties known to modulate the neuromagnetic signal. The tone complex stimuli only diverged on the value of the missing fundamental component. Principal Findings: We compared the M100 latencies of these tone complexes to the M100 latencies elicited by their respective pure tone (spectral pitch) counterparts. The M100 latencies for the tone complexes matched their pure sinusoid counterparts, while also replicating the M100 temporal latency response curve found in previous studies. Conclusions: Our findings suggest that listeners are reconstructing the inferred pitch by roughly 100 ms after stimulus onset and are consistent with previous electrophysiological research suggesting that the inferential pitch is perceived i
Psychopathology predicts the outcome of medial branch blocks with corticosteroid for chronic axial low back or cervical pain: a prospective cohort study
<p>Abstract</p> <p>Background</p> <p>Comorbid psychopathology is an important predictor of poor outcome for many types of treatments for back or neck pain. But it is unknown if this applies to the results of medial branch blocks (MBBs) for chronic low back or neck pain, which involves injecting the medial branch of the dorsal ramus nerves that innervate the facet joints. The objective of this study was to determine whether high levels of psychopathology are predictive of pain relief after MBB injections in the lumbar or cervical spine.</p> <p>Methods</p> <p>This was a prospective cohort study. Consecutive patients in a pain medicine practice undergoing MBBs of the lumbar or cervical facets with corticosteroids were recruited to participate. Subjects were selected for a MBB based on operationalized selection criteria and the procedure was performed in a standardized manner. Subjects completed the Brief Pain Inventory (BPI) and the Hospital Anxiety and Depression Scale (HADS) just prior to the procedure and at one-month follow up. Scores on the HADS classified the subjects into three groups based on psychiatric symptoms, which formed the primary predictor variable: <it>Low</it>, <it>Moderate</it>, or <it>High </it>levels of psychopathology. The primary outcome measure was the percent improvement in average daily pain rating one-month following an injection. Analysis of variance and chi-square were used to analyze the analgesia and functional rating differences between groups, and to perform a responder analysis.</p> <p>Results</p> <p>Eighty six (86) subjects completed the study. The <it>Low </it>psychopathology group (n = 37) reported a mean of 23% improvement in pain at one-month while the <it>High </it>psychopathology group (n = 29) reported a mean worsening of -5.8% in pain (p < .001). Forty five percent (45%) of the <it>Low </it>group had at least 30% improvement in pain versus 10% in the <it>High </it>group (p < .001). Using an analysis of covariance, no baseline demographic, social, or medical variables were significant predictors of pain improvement, nor did they mitigate the effect of psychopathology on the outcome.</p> <p>Conclusion</p> <p>Psychiatric comorbidity is associated with diminished pain relief after a MBB injection performed with steroid at one-month follow-up. These findings illustrate the importance of assessing comorbid psychopathology as part of a spine care evaluation.</p
Evidence for Shared Cognitive Processing of Pitch in Music and Language
Language and music epitomize the complex representational and computational capacities of the human mind. Strikingly similar in their structural and expressive features, a longstanding question is whether the perceptual and cognitive mechanisms underlying these abilities are shared or distinct β either from each other or from other mental processes. One prominent feature shared between language and music is signal encoding using pitch, conveying pragmatics and semantics in language and melody in music. We investigated how pitch processing is shared between language and music by measuring consistency in individual differences in pitch perception across language, music, and three control conditions intended to assess basic sensory and domain-general cognitive processes. Individualsβ pitch perception abilities in language and music were most strongly related, even after accounting for performance in all control conditions. These results provide behavioral evidence, based on patterns of individual differences, that is consistent with the hypothesis that cognitive mechanisms for pitch processing may be shared between language and music.National Science Foundation (U.S.). Graduate Research Fellowship ProgramEunice Kennedy Shriver National Institute of Child Health and Human Development (U.S.) (Grant 5K99HD057522
Effect of gender difference on platelet reactivity
Background Previous studies have suggested that women do not accrue equal therapeutic benefit from antiplatelet medication as compared with men. The physiological mechanism and clinical implications behind this gender disparity have yet to be established. Methods On-treatment platelet reactivity was determined in 717 men and 234 women on dual antiplatelet therapy, undergoing elective coronary stent implantation. Platelet function testing was performed using arachidonic acid and adenosine diphosphate-induced light transmittance aggregometry (LTA) and the VerifyNow P2Y12 and Aspirin assays. Also the incidence of all-cause death, non-fatal acute myocardial infarction, stent thrombosis and ischaemic stroke was evaluated. Results Women had higher baseline platelet counts than men. Women exhibited a higher magnitude of on-aspirin platelet reactivity using LTA, but not using the VerifyNow Aspirin assay. The magnitude of on-clopidogrel platelet reactivity was significantly higher in women as compared with men with both tests used. The cut-off value to identify patients at risk as well as the incidence of clinical endpoints was similar between women and men (16/234[6.8%] vs. 62/717[8.6%], p=0.38). Conclusion Although the magnitude of platelet reactivity was higher in women, the absolute difference between genders was small and both the cut-off value to identify patients at risk and the incidence of the composite endpoint were similar between genders. Thus, it is unlikely that the difference in platelet reactivity accounts for a worse prognosis in women
The Effect of Plant Inbreeding and Stoichiometry on Interactions with Herbivores in Nature: Echinacea angustifolia and Its Specialist Aphid
Fragmentation of once widespread communities may alter interspecific interactions by changing genetic composition of interacting populations as well as their abundances and spatial distributions. In a long-term study of a fragmented population of Echinacea angustifolia, a perennial plant native to the North American prairie, we investigated influences on its interaction with a specialist aphid and tending ants. We grew plant progeny of sib-matings (I), and of random pairings within (W) and between (B) seven remnants in a common field within 8 km of the source remnants. During the fifth growing season, we determined each plant's burden of aphids and ants, as well as its size and foliar elemental composition (C, N, P). We also assayed composition (C, N) of aphids and ants. Early in the season, progeny from genotypic classes B and I were twice as likely to harbor aphids, and in greater abundance, than genotypic class W; aphid loads were inversely related to foliar concentration of P and positively related to leaf N and plant size. At the end of the season, aphid loads were indistinguishable among genotypic classes. Ant abundance tracked aphid abundance throughout the season but showed no direct relationship with plant traits. Through its potential to alter the genotypic composition of remnant populations of Echinacea, fragmentation can increase Echinacea's susceptibility to herbivory by its specialist aphid and, in turn, perturb the abundance and distribution of aphids
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