bluuebunny/crossref_metadata_2025_split huggingface dataset:
Long‐term potentiation of human visual evoked responses
Authors: Teyler Timothy J. , Hamm Jeff P. , Clapp Wesley C. , Johnson Blake W. , Corballis Michael C. , Kirk Ian J. 
Published: January 2009

AbstractLong‐term potentiation (LTP) is a candidate synaptic mechanism underlying learning and memory that has been studied extensively at the cellular and molecular level in laboratory animals. To date, LTP has only been directly demonstrated in humans in isolated cortical tissue obtained from patients undergoing surgery, where it displays properties identical to those seen in non‐human preparations. Inquiry into the functional significance of LTP has been hindered by the absence of a human model. Here we give the first demonstration that the rapid repetitive presentation of a visual checkerboard (a photic ‘tetanus’) leads to a persistent enhancement of one of the early components of the visual evoked potential in normal humans. The potentiated response is largest in the hemisphere contralateral to the tetanized visual hemifield and is limited to one component of the visual evoked response (the N1b). The selective potentiation of only the N1b component makes overall brain excitability changes unlikely and suggests that the effect is due instead to an LTP process. While LTP is known to exist in the human brain, the ability to elicit LTP from non‐surgical patients will provide a human model system allowing the detailed examination of synaptic plasticity in normal subjects and may have future clinical applications in the assessment of cognitive disorders.
Binding of motion and colour is early and automatic
Authors: Blaser Erik , Papathomas Thomas , Vidnyánszky Zoltán 
Published: January 2009

AbstractAt what stages of the human visual hierarchy different features are bound together, and whether this binding requires attention, is still highly debated. We used a colour‐contingent motion after‐effect (CCMAE) to study the binding of colour and motion signals. The logic of our approach was as follows: if CCMAEs can be evoked by targeted adaptation of early motion processing stages, without allowing for feedback from higher motion integration stages, then this would support our hypothesis that colour and motion are bound automatically on the basis of spatiotemporally local information. Our results show for the first time that CCMAE's can be evoked by adaptation to a locally paired opposite‐motion dot display, a stimulus that, importantly, is known to trigger direction‐specific responses in the primary visual cortex yet results in strong inhibition of the directional responses in area MT of macaques as well as in area MT+ in humans and, indeed, is perceived only as motionless flicker. The magnitude of the CCMAE in the locally paired condition was not significantly different from control conditions where the different directions were spatiotemporally separated (i.e. not locally paired) and therefore perceived as two moving fields. These findings provide evidence that adaptation at an early, local motion stage, and only adaptation at this stage, underlies this CCMAE, which in turn implies that spatiotemporally coincident colour and motion signals are bound automatically, most probably as early as cortical area V1, even when the association between colour and motion is perceptually inaccessible.
m‐Chlorophenylpiperazine exacerbates perception of salicylate‐induced tinnitus in rats
Authors: Guitton Matthieu J. , Pujol Rémy , Puel Jean‐Luc 
Published: January 2009

AbstractThe serotonin receptor 5‐HT2C agonist m‐chlorophenylpiperazine (mCPP) has been widely used to induce anxiety‐like states in animals and anxiety in humans. We here addressed the effect of an intraperitoneal injection of mCPP on the perception of tinnitus in a behavioural protocol based on an active avoidance paradigm. In control saline‐treated animals, mCPP did not change compound action potential audiograms or measurable tinnitus. In contrast, mCPP to animals demonstrating salicylate‐induced tinnitus exacerbated tinnitus perception by nearly twofold. We went on to test whether manipulation of the peripheral generator of tinnitus (i.e. the cochlea) could extinguish this exacerbated perception by applying the N‐methyl‐d‐aspartate (NMDA) antagonist 7‐chlorokynurenate (7‐CK) into cochlear fluids using a 7‐CK‐soaked Gelfoam ball placed on the round window of each of the animals' two ears. In addition to blocking the tinnitus induced by salicylate alone, 50 µm of 7‐CK clearly abolished tinnitus in animals receiving salicylate and an injection of mCPP. The demonstration that cochlear NMDA receptor blockade abolishes the exacerbated perception of tinnitus is highly relevant in terms of treatment. In addition to psychotherapeutic treatment that may help to attenuate an individual's perception of tinnitus, targeting cochlear NMDA receptors represents a promising therapeutic strategy, even in depressed or chronically anxious patients.
The suprachiasmatic nucleus controls the daily variation of plasma glucose via the autonomic output to the liver: are the clock genes involved?
Authors: Cailotto Cathy , La Fleur Susanne E. , Van Heijningen Caroline , Wortel Joke , Kalsbeek Andries , Feenstra Matthijs , Pévet Paul , Buijs Ruud M. 
Published: January 2009

AbstractIn order to drive tissue‐specific rhythmic outputs, the master clock, located in the suprachiasmatic nucleus (SCN), is thought to reset peripheral oscillators via either chemical and hormonal cues or neural connections. Recently, the daily rhythm of plasma glucose (characterized by a peak before the onset of the activity period) has been shown to be directly driven by the SCN, independently of the SCN control of rhythmic feeding behaviour. Indeed, the daily variation in glucose was not impaired unless the scheduled feeding regimen (six‐meal schedule) was associated with an SCN lesion. Here we show that the rhythmicity of both clock‐gene mRNA expression in the liver and plasma glucose is not abolished under such a regular feeding schedule. Because the onset of the activity period and hyperglycemia are correlated with an increased sympathetic tonus, we investigated whether this autonomic branch is involved in the SCN control of plasma glucose rhythm and liver rhythmicity. Interestingly, hepatic sympathectomy combined with a six‐meal feeding schedule resulted in a disruption of the plasma glucose rhythmicity without affecting the daily variation in clock‐gene mRNA expression in the liver. Taking all these data together, we conclude that (i) the SCN needs the sympathetic pathway to the liver to generate the 24‐h rhythm in plasma glucose concentrations, (ii) rhythmic clock‐gene expression in the liver is not dependent on the sympathetic liver innervation and (iii) clock‐gene rhythmicity in liver cells is not sufficient for sustaining a circadian rhythm in plasma glucose concentrations.
Projections from the hippocampal region to the mammillary bodies in macaque monkeys
Authors: Aggleton John P. , Vann Seralynne D. , Saunders Richard C. 
Published: January 2009

AbstractA combination of anterograde and retrograde tracers mapped the direct hippocampal and parahippocampal inputs to the mammillary bodies in two species of macaque monkey. Dense projections arose from pyramidal cells in layer III of the subiculum and prosubiculum, and terminated in the medial mammillary nucleus. While there was no evidence of an input from the dentate gyrus or fields CA1–3, a small contribution arose from the presubiculum and entorhinal cortices. All of the hippocampal and parahippocampal projections to the mammillary bodies appeared to use the fornix as a route. The caudal portions of the subiculum and prosubiculum contained the greatest numbers of cells projecting to the mammillary bodies. A light contralateral projection to the medial mammillary nucleus was also observed, although this appeared to arise primarily from the more rostral portions of the subiculum and prosubiculum. There was a crude topography within the medial mammillary nucleus, with the caudal subicular projections terminating in the mid and dorsal portions of the nucleus while the rostral subicular and entorhinal projections terminated in the ventral and lateral portions of the medial nucleus. Light ipsilateral projections throughout the lateral mammillary nucleus were sometimes observed. Comparisons with related studies of the macaque brain showed that the dense hippocampal projections to the mammillary bodies arise from a population of subicular cells separate from those that project to the anterior thalamic nuclei, even though the major output from the mammillary bodies is to the anterior thalamic nuclei. Other comparisons revealed underlying similarities with the corresponding projections in the rat brain.
Consequences of partial and severe dopaminergic lesion on basal ganglia oscillatory activity and akinesia
Authors: Tseng Kuei Y. , Kargieman Lucila , Gacio Sebastian , Riquelme Luis A. , Murer M. Gustavo 
Published: January 2009

AbstractSevere chronic dopamine (DA) depletion increases the proportion of neurons in the basal ganglia that fire rhythmic bursts of action potential (LFO units) synchronously with the cortical oscillations. Here we report on how different levels of mesencephalic DA denervation affect substantia nigra pars reticulata (SNpr) neuronal activity in the rat and its relationship to akinesia (stepping test). Chronic nigrostriatal lesion induced with 0 (control group), 4, 6 or 8 µg of 6‐hydroxydopamine (6‐OHDA) into the medial forebrain bundle resulted in a dose‐dependent decrease of tyrosine hydroxylase positive (TH+) neurons in the SN and ventral tegmental area (VTA). Although 4 µg of 6‐OHDA reduced the number of TH+ neurons in the SN by ∼60%, both stepping test performance and SNpr neuronal activity remained indistinguishable from control animals. By contrast, animals that received 6 µg of 6‐OHDA showed a marked reduction of TH+ cells in the SN (∼75%) and VTA (∼55%), a significant stepping test deficit and an increased proportion of LFO units. These changes were not dramatically enhanced with 8 µg 6‐OHDA, a dose that induced an extensive DA lesion (> 95%) in the SN and ∼70% reduction of DA neurons in the VTA. These results suggest a threshold level of DA denervation for both the appearance of motor deficits and LFO units. Thus, the presence of LFO activity in the SNpr is not related to a complete nigrostriatal DA neuron depletion (ultimate stage parkinsonism); instead, it may reflect a functional disruption of cortico‐basal ganglia dynamics associated with clinically relevant stages of the disease.
A weight‐based formula for tracheal tube size in children
Authors: EIPE NAVEEN , BARROWMAN NICHOLAS , WRITER HILARY , DOHERTY DERMOT 
Published: January 2009

SummaryObjective:  Age (in years) of the child has conventionally been used in formulae to estimate the tracheal tube (TT) size. The objective of this retrospective study was to test a weight‐based formula (WBF) for uncuffed oral TT in children and compare it with the conventional age‐based formula (ABF).Methods:  The patient’s age, weight, and size of TT internal diameter (ID) were recorded. For comparative analysis, the actual TT size used was compared with predicted TT size, calculated using both the standard ABF [ID = age (years)/4 + 4 mm] and the WBF [ID = weight (kg)/10 + 3.5 mm].Results:  The Pearson’s correlation coefficient for age and actual TT size used was 0.77 (95% CI: 0.74–0.80) and between weight and actual TT used was 0.70 (95% CI: 0.66–0.74). The ABF correctly predicted 51.3% of TT sizes while the WBF correctly predicted 44.8% of TT sizes (P = 0.01). The measures of agreement between the actual and predicted TT size were 0.35 and 0.27 for the ABF and WBF respectively. The difference between the percentages of paired predictions for the ABF and WBF was statistically significant (P < 0.001) suggesting that, when correctly predicting the actual tube size used, the WBF functions for a different subset of the patient cohort than the ABF.Conclusions:  This study suggests that in this patient cohort, the WBF is statistically inferior to the conventional ABF. However, our findings also suggest that the WBF may correctly predict TT sizes in a subset of patients in whom the ABF is inaccurate.
Intraoperative transesophageal echocardiography is beneficial for hemodynamic stabilization during left ventricular assist device implantation in children
Authors: SCOHY THIERRY V. , GOMMERS DIEDERIK , MAAT ALEXANDER P.W.M. , DEJONG PETER L. , BOGERS AD J.J.C. , HOFLAND JAN 
Published: January 2009

SummaryBackground:  Mechanical circulatory support, with a left ventricular assist device (LVAD) is used in an increasing number of children for treatment of advanced heart failure as bridge‐to‐transplant. To date no data are available and no studies have defined the role of intraoperative transesophageal echocardiography (TEE) for hemodynamic stabilization during Centrimag Levitronix centrifugal pump implantation in children.Methods:  Children with therapy resistant heart failure, undergoing LVAD implantation using Berlin Heart Excor pediatric cannula connected to a Levitronix Centrifumag pump, are intraoperatively monitored using an Oldelft micromultiplane TEE. Intraoperative TEE is specially used to monitor right ventricular (RV) and left ventricular (LV) function, correct position of the cannulas and response to pharmacological treatment.Results:  In five consecutive patients RV function was assessed by TEE after starting LVAD Levitronix centrifugal pump. Initial RV failure presents with RV dilation and LV collapse. After titration of vasopressor and inotropic agents, RV contractility improved and thereby the filling of the LV. In one child, despite those measures the RV showed no improvement by TEE and a Levitronix right ventricular assist device to support the RV function was implanted as well. All patients could hemodynamically be stabilized before transport to the intensive care unit.Conclusion:  The complex interaction of the RV and LV function and correct positioning of the cannula, during LVAD implantation in children with end‐stage cardiac failure is improved by simultaneous visualization of cardiac performance of both ventricles and cannula positioning by means of intraoperative multiplane TEE.
Healthcare provider–child–parent communication in the preoperative surgical setting
Authors: KAIN ZEEV N. , MACLAREN JILL E. , HAMMELL CARRIE , NOVOA CRISTINA , FORTIER MICHELLE A. , HUSZTI HEATHER , MAYES LINDA 
Published: January 2009

SummaryObjectives:  Although preoperative preparation programs were once common, most children currently undergoing outpatient surgery are first exposed to the hospital on the day of the procedure. It is advocated that these outpatient children undergo the preparation just prior to surgery.Aim:  To assess the amount of time that healthcare providers spend with children and families on the day of surgery in the preoperative area.Materials and Methods:  The study used video infrastructure in the preoperative holding area of Yale New Haven Children’s Hospital to record all interactions between children, families, and healthcare providers. Videotapes were coded to characterize and quantify behaviors of healthcare professionals.Results:  On the day of surgery, healthcare providers spent medians of 2.75–4.81 min interacting with children and parents in the preoperative area. Families spent a median of 46.5 min in the preoperative area. Healthcare professionals spent the most time in medical talk (averages of 42.5–48.2% of time spent with family) and little time was spent in nonmedical talk (range of 6.2–6.9% of time spent with family). Anesthesiologists and surgeons spent 28% and 18% of the interview in talk to children; admitting nurses spent more of the interview talking to children (43%).Conclusions:  Families interact with healthcare providers for only a small proportion of the time they spent in the preoperative area. This is likely to be a result of increased production pressure in the perioperative settings and has implications for providing preparation for surgery on the morning of the procedure.
Objective amount of limb fat in HIV‐infected subjects with subjective diagnosis of lipoatrophy
Authors: Martínez E , Larrousse M , Podzamczer D , Gatell JM 
Published: January 2009

BackgroundThe relationship between the subjective diagnosis of lipoatrophy and the objective amount of limb fat loss in HIV‐infected adults is unclear.MethodsUsing Medline, we identified published articles reporting the amount of arm, leg or limb fat measured by dual X‐ray absorptiometry in HIV‐infected patients with moderate‐severe lipoatrophy and in healthy non‐HIV‐infected adults. We calculated the relative content of fat in the limbs, arms and legs of lipoatrophic patients with regard to the weighted arithmetic means of those fat values in healthy controls.ResultsWe found 799 patients from 10 articles, and 73 healthy controls from two articles. Limb fat ranged from 2.6 to 4.4 kg in patients, and from 7.1 to 7.2 kg in controls. Both patients and controls were almost exclusively men, of white race, and in their forties. Weighted arithmetic means of arm, leg and limb fat in HIV‐infected patients with clinically evident lipoatrophy were 1.0, 2.1 and 3.1 kg, respectively (48, 41 and 43% relative to healthy non‐HIV‐infected males, respectively).ConclusionsThe diagnosis of lipoatrophy was highly correlated with the amount of limb fat, irrespective of the investigators. HIV‐infected men with clinically evident lipoatrophy had a limb fat loss of >50% compared with non‐HIV‐infected healthy males.
Predicting the distribution of a suitable habitat for the white stork in Southern Sweden: identifying priority areas for reintroduction and habitat restoration
Authors: Olsson O. , Rogers D. J. 
Published: January 2009

AbstractThe loss of wetlands and semi‐natural grasslands throughout much of Europe has led to a historic decline of species associated with these habitats. The reinstatement of these habitats, however, requires spatially explicit predictions of the most suitable sites for restoration, to maximize the ecological benefit per unit effort. One species that demonstrates such declines is the white storkCiconia ciconia, and the restoration of habitat for this flagship species is likely to benefit a suite of other wetland and grassland biota. Storks are also being reintroduced into southern Sweden and elsewhere, and thea prioriidentification of suitable sites for reintroduction will greatly improve the success of such programmes. Here a simple predictive habitat‐use model was developed, where only a small but reliable presence‐only dataset was available. The model is based on the extent and relative soil moisture of semi‐natural pastures, the extent of wetlands and the extent of hayfields in southern Sweden. Here the model was used to predict the current extent of stork habitat that is suitable for successful breeding, and the extent of habitat that would become suitable with moderate habitat restoration. The habitat model identifies all 10 occupied nesting sites where breeding is currently successful. It also identifies ∼300 km2of habitat that is predicted to be suitable stork habitat, but that is presently unused; these sites were identified as potential areas for stork reintroduction. The model also identifies over 100 areas where moderate habitat restoration is predicted to have a disproportionate effect (relative to the restoration effort) on the area of suitable habitat for storks; these sites were identified as priorities for habitat restoration. By identifying areas for reintroduction and restoration, such habitat suitability models have the potential to maximize the effectiveness of such conservation programmes.
The role of infectious diseases in biological conservation
Authors: Smith K. F. , Acevedo‐Whitehouse K. , Pedersen A. B. 
Published: January 2009

AbstractRecent increases in the magnitude and rate of environmental change, including habitat loss, climate change and overexploitation, have been directly linked to the global loss of biodiversity. Wildlife extinction rates are estimated to be 100–1000 times greater than the historical norm, and up to 50% of higher taxonomic groups are critically endangered. While many types of environmental changes threaten the survival of species all over the planet, infectious disease has rarely been cited as the primary cause of global species extinctions. There is substantial evidence, however, that diseases can greatly impact local species populations by causing temporary or permanent declines in abundance. More importantly, pathogens can interact with other driving factors, such as habitat loss, climate change, overexploitation, invasive species and environmental pollution to contribute to local and global extinctions. Regrettably, our current lack of knowledge about the diversity and abundance of pathogens in natural systems has made it difficult to establish the relative importance of disease as a significant driver of species extinction, and the context when this is most likely to occur. Here, we review the role of infectious diseases in biological conservation. We summarize existing knowledge of disease‐induced extinction at global and local scales and review the ecological and evolutionary forces that may facilitate disease‐mediated extinction risk. We suggest that while disease alone may currently threaten few species, pathogens may be a significant threat to already‐endangered species, especially when disease interacts with other drivers. We identify control strategies that may help reduce the negative effects of disease on wildlife and discuss the most critical challenges and future directions for the study of infectious diseases in the conservation sciences.
Sampling tiger ungulate prey by the distance method: lessons learned in Bardia National Park, Nepal
Authors: Wegge P. , Storaas T. 
Published: January 2009

AbstractBecause tigerPanthera tigrisnumbers are regulated by their prey base, prey abundance needs to monitored and estimated reliably. Recently, distance sampling has been adopted as the most appropriate method and is now becoming the standard monitoring protocol in all tiger range countries in south Asia. However, the accuracy of the density estimates generated by this method has not been assessed. From total counts within habitat blocks, we obtained accurate density estimates of ungulates within three main habitats in Bardia National Park, Nepal. We then applied the distance sampling method in the same habitats and compared the results. Distance sampling on foot in dense habitats (riverine forest and tallgrass floodplain) violated method assumptions, and sampling from vehicle along roads gave biased estimates. Sampling from elephant back worked well in all habitat types, but owing to their behaviour, the density of barking deerMuntiacus muntjakwas underestimated. The accuracy of the estimates varied with sampling effort; for the very abundant chital deerAxis axis, estimates varied markedly at <200 animal observations, but converged at larger sample sizes to a similar point estimate as intensive block counts when approaching 300 observations. For the less abundant species, with <20 observations along >100 km of transect lines, the confidence intervals were quite high, and, hence, of limited value for detecting short‐term populations trends. It is therefore difficult to obtain accurate density estimates of rare species by the distance method. In areas consisting of dense habitats, we recommend that the food base of tiger be estimated by distance sampling from elephant back, not on foot, directed at the main and most abundant prey species. For rare species, encounter rates obtained simultaneously may then serve as indices of relative abundances.