bluuebunny/crossref_metadata_2025 huggingface dataset:
Popliteal Aneurysms: From John Hunter to the 21st Century
Authors: Galland RB
Published: August 2007

Popliteal aneurysms are rare and tend to occur in older men with significant co-morbidity. Historically, management of popliteal aneurysms can be considered in three broad groups: (i) the technique of Antyllus; (ii) techniques relying upon a collateral circulation; and (iii) techniques involving maintenance or restoration of circulation. Bypass and exclusion is currently been challenged by endovascuiar techniques which show promise in selected cases.

Current controversies in popliteal aneurysms management are: when to repair asymptomatic aneurysms, what operation to do and how to manage acute thrombosis. These have been addressed by studying, prospectively, 73 patients presenting with 116 popliteal aneurysms. Diameter greater than 2 cm is often stated as being an indication for elective operation in asymptomatic popliteal aneurysms. However, distortion of the aneurysm appears to be at least as important as size in determining whether symptoms are likely to develop. Of 17 popliteal aneurysms followed for a median of 34 months with a diameter 2–3 cm and distortion less than 45°, none thrombosed. This is no worse than patency following elective bypass (P= 0.064). Popliteal aneurysms greater than 3 cm in diameter in patients who are unfit or who declined an operation were significantly more likely to develop thrombosis or any other symptom (P = 0.01 and P = 0.004, respectively). Popliteal aneurysms less than 3 cm in diameter with distortion less than 45° can safely be managed by ultrasound surveillance. Popliteal aneurysms with greater diameter or distortion are best operated upon.

Bypass, combined with proximal and distal ligation of the aneurysm, resulted in 5-year graft patency of 78% and 65% for popliteal aneurysms originally patent or thrombosed, respectively, with good long-term exclusion of the aneurysm.

In addition to the general complications of intra-arterial thrombolysis, acute deterioration of the limb during lysis appears to be a particular problem when dealing with thrombosed popliteal aneurysms. It occurs in about 13% of cases which compares with 2% when dealing with thrombosed grafts or native arteries. Intra-arterial thrombolysis for thrombosed popliteal aneurysms is associated with unacceptabiy high numbers of complications and thrombolysis should be reserved for intra-operative use only.
Giant Haemangioma of the Liver: Is Enucleation Better than Resection?
Authors: Singh Rajneesh Kumar , Kapoor Sorabh , Sahni Peush , Chattopadhyay Tushar K
Published: August 2007

INTRODUCTION

Haemangioma is the most common liver tumour. Treatment is indicated for symptomatic tumours, rapid increase in size, rupture or doubt in diagnosis. There is continuing debate regarding the ideal method of surgical treatment for liver haemangiomas, with some surgeons favouring enucleation over liver resection.

PATIENTS AND METHODS

Retrospective analysis of prospectively compiled database of patients who were surgically treated for liver haemangioma.

RESULTS

Between 1987 and 2003, we operated on 21 patients with liver haemangioma. Pre-operative diagnosis on imaging was made in 16 patients (13 symptomatic, 3 had progressive increase in size). In five patients, the indication of surgery was uncertain diagnosis. Enucleation was performed in 9 patients and liver resection in 12. The size of the haemangioma was similar in the enucleation and resection groups (8.9 cm versus 10 cm; P = 0.85). The mean intra-operatiive blood loss was significantly less in the enucleation group (400 ml versus 1330 ml; P = 0.004). The mean operative time was significantly less in the enucleation group as compared to the resection group (170 min versus 230 min; P = 0.035). Five patients had major postoperative morbidity in the resection group as compared to none in the enucleation group (P = 0.045). The duration of hospital stay was significantly longer in the resection group.(9.9 days versus 5.6 days; P = 0.005).

CONCLUSIONS

Enucleation of liver haemangiomas is safer, quicker and associated with less morbidity than liver resection. Except for some situations, such as uncertain diagnosis or total replacement of a lobe, we recommend enucleation as the surgical procedures of choice for the treatment of hepatic haemangiomas.
Modern Perspectives in the Treatment of Chronic Anal Fissures
Authors: Bhardwaj R , Parker MC
Published: August 2007

INTRODUCTION

Anal fissures are commonly encountered in routine colorectal practice. Developments in the pharmacological understanding of the internal anal sphincter have resulted in more conservative approaches towards treatment. Simple measures are often effective for early fissures. Glyceryl trinitrate is well established as a first-line pharmacological therapy. The roles of diltiazem and botulinum, particularly as rescue therapy, are not well understood. Surgery has a defined role and should not be discounted completely.

METHODS

Data were obtained from Medline publications citing ‘anal fissure’. Manual cross-referencing of salient articles was conducted. We have sought to highlight various controversies in the management of anal fissures.

FINDINGS

Acute fissures may heal spontaneously, although simple conservative measures are sufficient. Idiopathic chronic anal fissures need careful evaluation to decide what therapy is suitable. Pharmacological agents such as glyceryl trinitrate (GTN), diltiazem and botulinum toxin have been subjected to most scrutiny. Though practices in the UK vary, GTN or diltiazem would be suitable as first-line therapy with botulinum toxin used as rescue treatment. Sphincterotomy is indicated for unhealed fissures; fissurectomy has been revisited and advancement flaps have a role in patients in whom sphincter division is not suitable.
The Problem Surgical Colleague
Authors: Mosley John G
Published: August 2007

‘All doctors are problem doctors.’ R Smith 1

The surgical profession, more than any other medical specialty, is constantly in the limelight. Frequently, concerns are expressed about our colleagues. The concerns may be personality clashes rather than failure in behaviour or performance.

Most concerns can be addressed locally with support from the Royal College Invited Review Mechanism of the National Clinical Assessment Service.

Unfortunately, if the concern is sufficiently serious or repetitive it may warrant referral to the General Medical Council (GMC) who alone has the right to withdraw a surgeon's medical registration. The surgeon will then be unable to work in the medical profession in this country.

The procedures the the surgeon must undergo if referred to the GMC are stressful and protracted. Even if successful the surgeon will probably be expected to undergo a period of retraining that will prove difficult to arrange.

New proposals to modify the GMC procedures will reduce the standard of proof to one of ‘balance of probabilities’.

The surgical profession should be accountable to its patients and colleagues. Will our Royal College rise to the challenge to establish itself as the bulwark of the surgical profession?
Risperidone- and Quetiapine-Induced Cholestasis
Authors: Wright Tara M , Vandenberg Amy M
Published: August 2007

Objective:

To describe a case of a patient who developed drug-induced cholestasis after being on risperidone maintenance therapy for 8 years.

Case Summary:

A 30-year-old male with schizoaffective disorder, bipolar type, and insulin-dependent diabetes mellitus had been stable on risperidone 6 mg at night for 8 years. His other medications included lithium 900 mg twice daily and enalapril 5 mg daily, as well as regular insulin and NPH insulin as needed. The patient developed cholestasis that resolved once risperidone was discontinued. Over the next 11 months, he tolerated trials of ziprasidone and olanzapine. When quetiapine was initiated, the patient developed signs and symptoms of cholestasis within 3 weeks after starting this medication. The signs and symptoms of cholestasis resolved with removal of quetiapine. The Naranjo probability scale indicated that these atypical antipsychotics (risperidone and quetiapine) were the probable cause of cholestasis in this patient.

Discussion:

It is well known that atypical antipsychotics can cause isolated asymptomatic increases in aminotransferase levels. Liver injury, both the hepatic and cholestatic type, has been described previously, although the incidence with atypical antipsychotics is rare.

Conclusions:

To our knowledge, this is the first case of cholestasis that developed after years of treatment and reappeared with another antipsychotic agent. Given that liver failure, of either the hepatic or cholestatic type, is a relatively rare phenomenon with atypical antipsychotics, it seems that the most reasonable approach to manage this risk is through education. By educating patients on early warning signs of hepatotoxicity, this rare but potentially fatal consequence could be detected early to allow appropriate intervention.
Risk of Infection with Intravenous Iron Therapy
Authors: Maynor Lena , Brophy Donald F
Published: August 2007

Objective:

To review the potential risks of administering intravenous iron to patients with infection.

Data Sources:

Literature was accessed through MEDLINE (1977–June 2007) and Google Scholar, using the terms intravenous iron, iron sucrose, ferric gluconate, iron dextran, and infection. In addition, reference citations from publications identified were reviewed.

Study Selection and Data Extraction:

All English-language articles identified from the data sources were evaluated. Studies that provided data relevant to the objective were used, including in vitro and animal studies.

Data Synthesis:

The role of iron in bacterial growth and the pathophysiology of cellular immunity create legitimate, yet theoretical, concerns that active infection may be exacerbated by the administration of intravenous iron. Human data relating to this issue are limited. A few small, human studies in a population with chronic kidney disease suggest a possible increased risk of developing an infection associated with intravenous iron; however, prospective human data directly linking intravenous iron to exacerbation of existing infection or infection-related mortality are lacking. In vitro data suggest that increased transferrin saturation related to iron administration may result in polymorphonuclear leukocyte dysfunction and decreased inhibition of bacterial growth. Sparse animal data have linked intravenous iron therapy with morbidity and mortality in sepsis models.

Conclusions:

Despite the limited human data, careful consideration of risk versus benefit should be used when administering intravenous iron to patients with ongoing infection. Additional clinical data are needed to determine whether intravenous iron administration worsens outcomes of patients with infection.
Subventricular Zone Stem Cells Are Heterogeneous with Respect to Their Embryonic Origins and Neurogenic Fates in the Adult Olfactory Bulb
Authors: Young Kaylene M. , Fogarty Matthew , Kessaris Nicoletta , Richardson William D.
Published: August 2007

We determined the embryonic origins of adult forebrain subventricular zone (SVZ) stem cells by Cre-lox fate mapping in transgenic mice. We found that all parts of the telencephalic neuroepithelium, including the medial ganglionic eminence and lateral ganglionic eminence (LGE) and the cerebral cortex, contribute multipotent, self-renewing stem cells to the adult SVZ. Descendants of the embryonic LGE and cortex settle in ventral and dorsal aspects of the dorsolateral SVZ, respectively. Both populations contribute new (5-bromo-2′-deoxyuridine-labeled) tyrosine hydroxylase- and calretinin-positive interneurons to the adult olfactory bulb. However, calbindin-positive interneurons in the olfactory glomeruli were generated exclusively by LGE-derived stem cells. Thus, different SVZ stem cells have different embryonic origins, colonize different parts of the SVZ, and generate different neuronal progeny, suggesting that some aspects of embryonic patterning are preserved in the adult SVZ. This could have important implications for the design of endogenous stem cell-based therapies in the future.
Human MST But Not MT Responds to Tactile Stimulation
Authors: Beauchamp Michael S. , Yasar Nafi E. , Kishan Neel , Ro Tony
Published: August 2007

Previous reports of tactile responses in human visual area MT/V5 have used complex stimuli, such as a brush stroking the arm. These complex moving stimuli are likely to induce imagery of visual motion, which is known to be a powerful activator of MT. The area described as “MT” in previous reports consists of at least two distinct cortical areas, MT and MST. Using functional magnetic resonance imaging, we separately localized human MT and MST and measured their response to vibrotactile stimuli unlikely to induce imagery of visual motion. Strong vibrotactile responses were observed in MST but not in MT. Vibrotactile responses in MST were approximately one-half as large as the response to visual motion and were distinct from those in another visual area previously reported to respond to tactile stimulation, the lateral occipital complex. To examine somatotopic organization, we separately stimulated the left and right hand and foot. No spatial segregation between hand and foot responses was observed in MST. The average response profile of MST was similar to that of somatosensory cortex, with a strong preference for the contralateral hand. These results offer evidence for the existence of somatosensory responses in MST, but not MT, independent of imagery of visual motion.
The Adult Visual Cortex Expresses Dynamic Synaptic Plasticity That Is Driven by the Light/Dark Cycle
Authors: Tsanov Marian , Manahan-Vaughan Denise
Published: August 2007

Experimental evidence derived fromin vitrostudies suggests that synaptic plasticity may be involved in information processing in the adult sensory cortex. Here, we demonstrate, for the first time, that synaptic plasticity that endures for >24 h can be elicited in the visual cortex of freely moving adult rats. Both long-term potentiation (LTP) and long-term depression (LTD) were evoked in layer 2/3 of the primary visual cortex after stimulation of the dorsal lateral geniculate nucleus. We found that synaptic plasticity within visual cortex synapses is not a static phenomenon, where a particular pattern of stimulation invariably evokes the same form of synaptic plasticity but rather fluctuates in association with diurnal luminance levels. Whereas acute (12 h) dark exposure drives intrinsic synaptic transmission to basal levels, light exposure (12 h) leads to synaptic potentiation. Furthermore, low-frequency stimulation at 3 Hz generates LTD in light-exposed animals, and LTP in dark-exposed animals, in close correlation with the time course of natural slow wave oscillations. Our data demonstrate that the adult visual cortex is in a perpetually dynamic state, where the direction of plasticity changes depends on the immediate visual experience.
Intrinsic, Light-Independent and Visual Activity-Dependent Mechanisms Cooperate in the Shaping of the Field Response in Rat Visual Cortex
Authors: Tsanov Marian , Manahan-Vaughan Denise
Published: August 2007

Do light intensity and behavioral state regulate synaptic plasticity in the visual cortex? We have shown previously that synaptic transmission in the visual cortex oscillates between elevated and depressed levels in accordance with the diurnal light–dark cycle. In this study, we examined the role of intrinsic, light-independent, and visual activity-driven sensory information on the field response during diurnal fluctuations, and examined the plasticity properties of the visual cortex under both conditions. Recordings were obtained from layer 2/3 of the primary visual cortex, of adult freely moving Long Evans rats, after stimulation of the dorsal lateral geniculate nucleus. We observed that visual experience during different states of vigilance leads to increased responsiveness, and plastic changes, in the strength of connections among neurons, consistent with a naturalistic shift in the induction thresholds for synaptic plasticity. We identified this phenomenon as BDNF-dependent. We also found that gamma oscillatory activity, which increases during active visual exploration, is tightly associated with suppression of cortical field potentials, suggesting that coincident changes in synaptic responsiveness and gamma oscillatory levels may reflect mechanisms for optimal stimulus-feature encoding. Translating into an increased signal-to-noise ratio, field depression could thus alter the efficacy of cortical visual processing. These data indicate that the adult visual cortex serves as a synaptic network, where the ability to process visual stimuli is dynamically modified by active visual exploration and arousal states.
Olfactory Bulb Gamma Oscillations Are Enhanced with Task Demands
Authors: Beshel Jennifer , Kopell Nancy , Kay Leslie M.
Published: August 2007

Fast oscillations in neural assemblies have been proposed as a mechanism to facilitate stimulus representation in a variety of sensory systems across animal species. In the olfactory system, intervention studies suggest that oscillations in the gamma frequency range play a role in fine odor discrimination. However, there is still no direct evidence that such oscillations are intrinsically altered in intact systems to aid in stimulus disambiguation. Here we show that gamma oscillatory power in the rat olfactory bulb during a two-alternative choice task is modulated in the intact system according to task demands with dramatic increases in gamma power during discrimination of molecularly similar odorants in contrast to dissimilar odorants. This elevation in power evolves over the course of criterion performance, is specific to the gamma frequency band (65–85 Hz), and is independent of changes in the theta or beta frequency band range. Furthermore, these high amplitude gamma oscillations are restricted to the olfactory bulb, such that concurrent piriform cortex recordings show no evidence of enhanced gamma power during these high-amplitude events. Our results display no modulation in the power of beta oscillations (15–28 Hz) shown previously to increase with odor learning in a Go/No-go task, and we suggest that the oscillatory profile of the olfactory system may be influenced by both odor discrimination demands and task type. The results reported here indicate that enhancement of local gamma power may reflect a switch in the dynamics of the system to a strategy that optimizes stimulus resolution when input signals are ambiguous.
Predicting Movement from Multiunit Activity
Authors: Stark Eran , Abeles Moshe
Published: August 2007

Previous studies have shown that intracortical activity can be used to operate prosthetic devices such as an artificial limb. Previously used neuronal signals were either the activity of tens to hundreds of spiking neurons, which are difficult to record for long periods of time, or local field potentials, which are highly correlated with each other. Here, we show that by estimating multiunit activity (MUA), the superimposed activity of many neurons around a microelectrode, and using a small number of electrodes, an accurate prediction of the upcoming movement is obtained. Compared with single-unit spikes, single MUA recordings are obtained more easily and the recordings are more stable over time. Compared with local field potentials, pairs of MUA recordings are considerably less redundant. Compared with any other intracortical signal, single MUA recordings are more informative. MUA is informative even in the absence of spikes. By combining information from multielectrode recordings from the motor cortices of monkeys that performed either discrete prehension or continuous tracing movements, we demonstrate that predictions based on multichannel MUA are superior to those based on either spikes or local field potentials. These results demonstrate that considerable information is retained in the superimposed activity of multiple neurons, and therefore suggest that neurons within the same locality process similar information. They also illustrate that complex movements can be predicted using relatively simple signal processing without the detection of spikes and, thus, hold the potential to greatly expedite the development of motor-cortical prosthetic devices.
Functional Specialization of the Primate Frontal Cortex during Decision Making: Figure 1.
Authors: Lee Daeyeol , Rushworth Matthew F. S. , Walton Mark E. , Watanabe Masataka , Sakagami Masamichi
Published: August 2007

Economic theories of decision making are based on the principle of utility maximization, and reinforcement-learning theory provides computational algorithms that can be used to estimate the overall reward expected from alternative choices. These formal models not only account for a large range of behavioral observations in human and animal decision makers, but also provide useful tools for investigating the neural basis of decision making. Nevertheless, in reality, decision makers must combine different types of information about the costs and benefits associated with each available option, such as the quality and quantity of expected reward and required work. In this article, we put forward the hypothesis that different subdivisions of the primate frontal cortex may be specialized to focus on different aspects of dynamic decision-making processes. In this hypothesis, the lateral prefrontal cortex is primarily involved in maintaining the state representation necessary to identify optimal actions in a given environment. In contrast, the orbitofrontal cortex and the anterior cingulate cortex might be primarily involved in encoding and updating the utilities associated with different sensory stimuli and alternative actions, respectively. These cortical areas are also likely to contribute to decision making in a social context.
Neural Antecedents of Financial Decisions: Figure 1.
Authors: Knutson Brian , Bossaerts Peter
Published: August 2007

To explain investing decisions, financial theorists invoke two opposing metrics: expected reward and risk. Recent advances in the spatial and temporal resolution of brain imaging techniques enable investigators to visualize changes in neural activation before financial decisions. Research using these methods indicates that although the ventral striatum plays a role in representation of expected reward, the insula may play a more prominent role in the representation of expected risk. Accumulating evidence also suggests that antecedent neural activation in these regions can be used to predict upcoming financial decisions. These findings have implications for predicting choices and for building a physiologically constrained theory of decision-making.
Understanding Neural Coding through the Model-Based Analysis of Decision Making: Figure 1.
Authors: Corrado Greg , Doya Kenji
Published: August 2007

The study of decision making poses new methodological challenges for systems neuroscience. Whereas our traditional approach linked neural activity to external variables that the experimenter directly observed and manipulated, many of the key elements that contribute to decisions are internal to the decider. Variables such as subjective value or subjective probability may be influenced by experimental conditions and manipulations but can neither be directly measured nor precisely controlled. Pioneering work on the neural basis of decision circumvented this difficulty by studying behavior in static conditions, in which knowledge of the average state of these quantities was sufficient. More recently, a new wave of studies has confronted the conundrum of internal decision variables more directly by leveraging quantitative behavioral models. When these behavioral models are successful in predicting a subject's choice, the model's internal variables may serve as proxies for the unobservable decision variables that actually drive behavior. This new methodology has allowed researchers to localize neural subsystems that encode hidden decision variables related to free choice and to study these variables under dynamic conditions.
CD200 Ligand–Receptor Interaction Modulates Microglial ActivationIn VivoandIn Vitro: A Role for IL-4
Authors: Lyons Anthony , Downer Eric J. , Crotty Suzanne , Nolan Yvonne M. , Mills Kingston H. G. , Lynch Marina A.
Published: August 2007

Deficits in cognitive function are associated with neuroinflammatory changes, typified by activation of glial cells and an alteration of the pro- and anti-inflammatory cytokine balance in the brain. Although there is evidence to suggest that activation of microglia is regulated by interaction with other cell types in the brain, the mechanism(s) involved is poorly understood. Here, we provide evidence that interaction between CD200 and its receptor plays a role in modulating microglial activation under conditions of chronic and acute inflammation of the brain. We report that interleukin-4 (IL-4) plays a central role in modulating expression of CD200 and identify a mechanism by which IL-4 directly controls microglial cell activation. Our findings provide the first demonstration of a role for IL-4 in modulating CD200 expression and suggest a mechanism for regulation of microglial activation in the intact CNS under inflammatory conditions.
Subthreshold Dendritic Signal Processing and Coincidence Detection in Dentate Gyrus Granule Cells
Authors: Schmidt-Hieber Christoph , Jonas Peter , Bischofberger Josef
Published: August 2007

Although dendritic signal processing has been extensively investigated in hippocampal pyramidal cells, only little is known about dendritic integration of synaptic potentials in dentate gyrus granule cells, the first stage in the hippocampal trisynaptic circuit. Here we combined dual whole-cell patch-clamp recordings with high-resolution two-photon microscopy to obtain detailed passive cable models of hippocampal granule cells from adult mice. Passive cable properties were determined by direct fitting of the compartmental model to the experimentally measured voltage responses to short and long current pulses. The data are best fit by a cable model with homogenously distributed parameters, including an average specific membrane resistance (Rm) of 38.0 kΩ cm2, a membrane capacitance (Cm) of 1.0 μF cm−2, and an intracellular resistivity (Ri) of 194 Ω cm. Computational analysis shows that signal propagation from somata into dendrites is more efficient in granule cells compared with CA1 pyramidal cells for both steady-state and sinusoidal voltage waveforms up to the gamma frequency range (f50%of 74 Hz). Similarly, distal synaptic inputs from entorhinal fibers can efficiently depolarize the somatic membrane of granule cells. Furthermore, the time course of distal dendritic synaptic potentials is remarkably fast, and temporal summation is restricted to a narrow time window in the range of ∼10 ms attributable to the rapid dendritic charge redistribution during transient voltage signals. Therefore, the structure of the granule cell dendritic tree may be critically important for precise dendritic signal processing and coincidence detection during hippocampus-dependent memory formation and retrieval.
Targeting of Retinal Axons Requires the Metalloproteinase ADAM10
Authors: Chen Yuanyuan , Hehr Carrie L. , Atkinson-Leadbeater Karen , Hocking Jennifer C. , McFarlane Sarah
Published: August 2007

The role of extrinsic cues in guiding developing axons is well established; however, the means by which the activity of these extrinsic cues is regulated is poorly understood. A disintegrin and metalloproteinase (ADAM) enzymes are Zn-dependent proteinases that can cleave guidance cues or their receptorsin vitro. Here, we identify the first example of a metalloproteinase that functions in vertebrate axon guidancein vivo. Specifically, ADAM10 is required for formation of the optic projection byXenopusretinal ganglion cell (RGC) axons.Xadam10mRNA is expressed in the dorsal neuroepithelium through which RGC axons extend. Pharmacological or molecular inhibition of ADAM10 within the brain each resulted in a failure of RGC axons to recognize their target. In contrast, molecular inhibition of ADAM10 within the RGC axons themselves had no effect. These data argue strongly that in the dorsal brain ADAM10 acts cell non-autonomously to regulate the guidance of RGC axons.
NMDA Di-Heteromeric Receptor Populations and Associated Proteins in Rat Hippocampus
Authors: Al-Hallaq Rana A. , Conrads Thomas P. , Veenstra Timothy D. , Wenthold Robert J.
Published: August 2007

Subunit composition of NMDA receptors (NMDARs) determines a range of physiological properties, downstream signaling effects, and binding partners. Differential localization of NR2A- or NR2B-containing NMDARs within the neuron and subunit-specific protein associations may explain differences in NR2A and NR2B contributions to synaptic plasticity and excitotoxic cell death. This question is complicated by the existence of tri-heteromeric complexes (NR1/NR2A/NR2B). To date, no quantitative biochemical determinations have been made of the relative abundance of different NMDAR populations in intact hippocampus, the region extensively correlated with NMDAR-dependent long-term potentiation. We investigated subunit composition and subunit-specific interactions in CA1/CA2 of rat hippocampus. Using sequential immunoprecipitations to deplete either NR2B or NR2A, di-heteromeric NR1/NR2A and NR1/NR2B receptor populations were isolated from postnatal day 7 (P7) hippocampus and P42 and 6-month-old CA1/CA2. Quantitative Western blot analysis revealed that 60–70% of NR2A and 70–85% of NR2B subunits were associated in NR1/NR2A or NR1/NR2B di-heteromeric complexes. Isolated di-heteromeric receptor fractions were used to examine NR2A- or NR2B-specific interactions with synapse-associated proteins. Our results indicate that NR2A- or NR2B-containing NMDARs associate similarly with postsynaptic density-95 (PSD-95), synapse-associated protein 102, and PSD-93 at P42. However, NR2A-containing receptors coimmunoprecipitated a greater proportion of the synaptic proteins neuronal nitric oxide synthase, Homer, and β-catenin. Finally, mass spectrometry analysis of isolated di-heteromeric receptors identified a novel NMDAR interactor, collapsin response mediator protein 2, which preferentially associates with NR2B-containing di-heteromeric NMDARs. In summary, in rat hippocampus, NR2A and NR2B exist primarily in di-heteromeric complexes that interact similarly with PSD-95-related proteins but are associated with different protein complexes.
Temporal Filtering of Reward Signals in the Dorsal Anterior Cingulate Cortex during a Mixed-Strategy Game
Authors: Seo Hyojung , Lee Daeyeol
Published: August 2007

The process of decision making in humans and other animals is adaptive and can be tuned through experience so as to optimize the outcomes of their choices in a dynamic environment. Previous studies have demonstrated that the anterior cingulate cortex plays an important role in updating the animal's behavioral strategies when the action outcome contingencies change. Moreover, neurons in the anterior cingulate cortex often encode the signals related to expected or actual reward. We investigated whether reward-related activity in the anterior cingulate cortex is affected by the animal's previous reward history. This was tested in rhesus monkeys trained to make binary choices in a computer-simulated competitive zero-sum game. The animal's choice behavior was relatively close to the optimal strategy but also revealed small systematic biases that are consistent with the use of a reinforcement learning algorithm. In addition, the activity of neurons in the dorsal anterior cingulate cortex that was related to the reward received by the animal in a given trial often was modulated by the rewards in the previous trials. Some of these neurons encoded the rate of rewards in previous trials, whereas others displayed activity modulations more closely related to the reward prediction errors. In contrast, signals related to the animal's choices were represented only weakly in this cortical area. These results suggest that neurons in the dorsal anterior cingulate cortex might be involved in the subjective evaluation of choice outcomes based on the animal's reward history.
Desensitization Properties of AMPA Receptors at the Cerebellar Mossy Fiber–Granule Cell Synapse
Authors: DiGregorio David A. , Rothman Jason S. , Nielsen Thomas A. , Silver R. Angus
Published: August 2007

Native AMPA receptors (AMPARs) exhibit rapid and profound desensitization in the sustained presence of glutamate. Desensitization therefore contributes to short-term depression at synapses in which glutamate accumulates. At synapses that do not exhibit desensitization-dependent depression, AMPARs are thought to be protected against prolonged or repetitive exposure to synaptically released glutamate. At the cerebellar mossy fiber to granule cell (GC) synapse, in which high release probability and glutamate spillover produce a substantial buildup of glutamate concentration in the cleft ([Glut]cleft) during high-frequency transmission, only moderate desensitization of the phasic AMPAR EPSC occurs. To investigate how such currents are produced, we examined the kinetic properties of synaptic AMPARs in GCs using glutamate uncaging. Photolysis of 4-methoxy-7-nitroindolinyl-cagedl-glutamate with large illumination spots produced step-like increases in [Glut]cleftthat could be used to systematically probe AMPAR kinetics. At low levels of activation, synaptic AMPARs exhibited little desensitization. With larger activations, the desensitization time course became faster, but the level of desensitization was only weakly dependent on receptor occupancy. Indeed, a substantial desensitization-resistant current component remained (17%) in saturating glutamate. Photolysis with small illumination spots produced brief [Glut]cleftwaveforms and transient AMPAR activations, similar to the EPSC current components. Paired-pulse uncaging with such spots revealed little desensitization after spillover-like activations and modest depression after activations that mimicked quantal and spillover components together. Our results show that GC AMPARs exhibit a resistance to desensitization at low occupancies and that this property is crucial for sustaining high-frequency transmission at a synapse in which glutamate accumulates.
Beatrice Medicine and the Anthropology of Education: Legacy and Vision for Critical Race/Critical Language Research and Praxis
Authors: Deyhle Donna
Published: August 2007

Over a 50‐year professional career, Dr. Beatrice Medicine never failed to assert the importance of Indigenous language rights or to challenge racism in the academy, public schools, and society. She urged educational anthropologists to confront racism in our research with Indigenous peoples. She challenged linguicism and urged the teaching of Native American languages in schools. Bea Medicine's legacy provides a compelling vision for the future of the field of educational anthropology, particularly in the domains of critical race theory and critical language studies. In this article, we consider both the legacy and the vision of Beatrice Medicine as they guide us to new arenas of research and praxis.
The Lives and Work of Beatrice Medicine and Vine Deloria Jr.
Authors: Brayboy Bryan McKinley Jones
Published: August 2007

In this article, we offer a tribute to the memories of Dr. Beatrice Medicine and Dr. Vine Deloria Jr., two of the most revered and celebrated Indigenous educators. We describe the legacy these scholars leave as one that calls on Indigenous communities to survive by both fighting against ongoing colonization and pursuing individual and communal well‐being. We respond to reflections offered by Troy Richardson, Donna Deyhle, and Teresa McCarty in this issue. Medicine's and Deloria's scholarship and leadership remind us about the importance of recognizing the wisdom of elders, of developing research that serves a community purpose, and of working toward the self‐education of Indigenous peoples through claiming power and sovereignty.
Bringing Navajo Storytelling Practices into Schools: The Importance of Maintaining Cultural Integrity
Authors: Eder Donna J.
Published: August 2007

This article examines storytelling practices among Navajos as one example of a non‐Western approach to education. The article discusses two stories—one regarding the perspectives of Navajo storytellers concerning the importance of the context of storytelling practices and the other about the research process that led to these perspectives. Eight storytellers were interviewed about storytelling practices in the past and those they would like to see in the future. Implications of the importance of key storytelling practices for Navajo education as well as for changes in Western approaches to schooling are presented.
The Power of Contexts: Teaching and Learning in Recently Desegregated Schools
Authors: Chapman Thandeka K.
Published: August 2007

The following critical ethnography interrogates what it means for urban students to learn in multicultural ways, given the oppressive historical and present contexts of their newly desegregated urban district. By retelling events that occurred in the district and the classroom, I present a picture of urban students who are willing to learn and engage in classroom activities when the activities do not threaten their emotional safety. Although their actions are understandable, the students' conscious decisions to disengage from school stifles learning opportunities that would allow them to empathize and connect with other students as a move toward individual and group empowerment. Using critical race theory, I problematize the possibilities for successful multicultural classrooms in urban districts with complex legacies of injustice and racial hostility.
The Fact of a Rumor: Anthony Trollope's The Eustace Diamonds
Authors: BEN-YISHAI AYELET
Published: August 2007

This essay joins recent scholarship on the epistemology of realist fiction by investigating the role of facts in the creation of fiction. Close scrutiny of Anthony Trollope's The Eustace Diamonds (1872) reveals several different processes of fact-making: legal ones as well as nonlegal communal endeavors such as rumor, gossip, and the regulation of propriety. The neat division whereby legal facts belong to the realm of the empirical and the facts of rumor belong to the communal does not hold in the novel, however: underneath the surface of almost any empirical and legal fact are traces and residues of a communal endeavor. The instability of facts and fact-making in the novel prompts a reconsideration of the epistemology of realist form and of novelistic probability: just how are fictional facts determined? Building on Irene Tucker's understanding of probability as a self-conscious reflection of the empirical, the essay argues that the ostensibly empirical epistemology of fictional probability is also a communal one. Moreover, the secular empirical rules of realism are not as stable—or empirical—as we have come to understand them. In the legal realm, this epistemological reconsideration shows how literary realism has drawn on the law not only to ground its famously empirical discourse but also to anchor novelistic truth in a communal endeavor. The Eustace Diamonds thus problematizes not only the production of fact in the novel but also the empiricist, positive-law tradition from which this concept emerged.
“Every Place Has a Ghetto…”: The Significance of Whites' Social and Residential Segregation
Authors: Bonilla‐Silva Eduardo , Embrick David G.
Published: August 2007

The residential and social segregation of whites from blacks creates a socialization process we refer to as “white habitus.” This white habitus limits whites' chances for developing meaningful relationships with blacks and other minorities spatially and psychologically. Using data from the 1997 Survey of College Students' Social Attitudes and the 1998 Detroit Area Study, we show that the spatial segregation experienced by whites from blacks fosters segregated lifestyles and leads them to develop positive views about themselves and negative views about blacks. First, we document the high levels of whites' residential and social segregation. Next, we examine how whites interpret their own self‐segregation. Finally, we examine how whites' segregation shapes their racial expressions, attitudes, cognitions, and even their sense of aesthetics as illustrated by their views on the subject of interracial marriage.
The Redeemed Old Head: Articulating a Sense of Public Self and Social Purpose
Authors: Young Alford A.
Published: August 2007

The notion of the “old head” has emerged as a formidable social type in studies of African American, low‐income, urban communities. The term refers to men who have had stable work histories and who reflect “mainstream” values concerning work ethic and social conduct. This analysis broadens the category of old head by exploring the views of men whose life courses have taken different turns than have traditional old heads. Through an analysis of the view of two African American men on their life experiences and efforts to serve as mentors to younger people in their lives, this article delivers an argument about the redeemed old head. This figure is defined in partial contrast to sociological depictions of traditional old heads in that the redeemed old head has led a life of profligate activity as a youth, but now has on his mind the interests and prospects of younger people, some of whom are involved in such profligate activity themselves. Elements of symbolic interactionist theory are employed to make sense of how the redeemed old head conceives of his public self and argues for the limits and possibilities for service as a mentor.
The 4G/4G Plasminogen Activator Inhibitor-1 Genotype Is Associated With Frequent Recurrence of Acute Otitis Media
Authors: Emonts Marieke , Wiertsema Selma P. , Veenhoven Reinier H. , Houwing-Duistermaat Jeanine J. , Walraven Vanessa , de Groot Ronald , Hermans Peter W.M. , Sanders Elisabeth A.M.
Published: August 2007

OBJECTIVES. Plasminogen activator inhibitor-1 counterregulates cell migration, adhesion, and tissue repair. The PAI1 4G/5G promoter polymorphism has an effect on expression levels of PAI1. After a first acute otitis media episode, children are at increased risk for a next episode. Because the PAI1 4G allele is associated with higher plasminogen activator inhibitor-1 production and, hence, decreased tissue repair, we hypothesize that this allele may contribute to increased recurrence of acute otitis media.

PATIENTS AND METHODS. The PAI1 4G/5G polymorphism was genotyped in 348 Dutch children aged 1 to 7 years who were suffering from recurrent acute otitis media and participating in a randomized, controlled trial and 463 healthy control subjects, representative of the general population.

RESULTS. No significant difference in PAI1 genotype distribution between the whole acute otitis media group and control subjects was observed. However, children with the PAI1 4G/4G genotype had an increased risk of more frequent acute otitis media episodes compared with those who were homozygous for the 5G variant, also after correction for cofactors. This finding was attributable to children <4 years of age.

CONCLUSIONS. Our findings suggest that the PAI1 4G/4G genotype is associated with an increased risk for the otitis-prone condition, potentially because of impaired healing after a previous otitis media episode.
Health-Related Quality of Life Among Preadolescent Children With Oral Clefts: The Mother's Perspective
Authors: Damiano Peter C. , Tyler Margaret C. , Romitti Paul A. , Momany Elizabeth T. , Jones Michael P. , Canady John W. , Karnell Michael P. , Murray Jeffrey C.
Published: August 2007

OBJECTIVE. The purpose of this study was to evaluate the factors that affect the health-related quality of life of preadolescent children with nonsyndromic oral clefts using the Pediatric Quality of Life Inventory instrument and to evaluate whether there were any differences related to the type of cleft or other factors.

METHODS. Data for this study were derived from telephone interviews with the parents of a statewide population of children who were in the Iowa Registry for Congenital and Inherited Disorders, were aged 2 to 12 years, had nonsyndromic oral clefts, and were born in Iowa between January 1, 1990, and December 31, 2000. Twenty-minute interviews were conducted with mothers of 104 children in the spring and summer of 2003; respondents then completed and mailed back Pediatric Quality of Life Inventory surveys 2 to 3 weeks after the interviews (69% participation rate).

RESULTS. After controlling for demographic characteristics, children with less severe speech problems had higher total Pediatric Quality of Life Inventory scores as well as higher physical and psychosocial health domain scores. Age and cleft type interacted, with younger children (aged 2–7 years) with a cleft lip or cleft lip and palate having higher health-related quality of life scores than children with an isolated cleft palate; however, this pattern was reversed for older children (aged 8–12 years).

CONCLUSIONS. Speech and aesthetic concerns seem to have been important factors affecting the health-related quality of life for children with oral clefts. These factors seem to be more important as children get closer to adolescence (ages 8–12 years) when acceptance by peers becomes more critical.
Management Guidelines for Mucopolysaccharidosis VI
Authors: Giugliani Roberto , Harmatz Paul , Wraith James E.
Published: August 2007

Mucopolysaccharidosis VI (Maroteaux-Lamy syndrome) is a lysosomal storage disease that is characterized by systemic clinical manifestations and significant functional impairment. Diagnosis and management are often challenging because of the considerable variability in symptom presentation and rate of progression. The optimal standard of care should be based on evidence from randomized, controlled trials, meta-analyses, systematic reviews, and expert opinion. In support of this goal, comprehensive management guidelines have been drafted by an international group of experts in the management of patients with mucopolysaccharidosis VI. The guidelines provide a detailed outline of disease manifestations by body system, recommendations for regular assessments, and an overview of current treatment options.