bluuebunny/crossref_metadata_2025 huggingface dataset:
Responses to Di-Sodium Guanosine 5′-Monophosphate and Monosodiuml-Glutamate in Taste Receptor Cells of Rat Fungiform Papillae
Authors: Lin Weihong , Ogura Tatsuya , Kinnamon Sue C.
Published: May 2006

The 5′-ribonucleotide guanosine 5′-monophosphate (GMP) is used widely as an umami taste stimulus and a potent flavor enhancer as it synergistically increases the umami taste elicited by monosodium glutamate. Transduction mechanisms for GMP and its synergy with glutamate are largely unknown. Using whole-cell patch-clamp and Ca2+ imaging, we examined responses to GMP, glutamate, and a mixture of GMP and glutamate in taste-receptor cells of rat fungiform papillae. Our electrophysiological results showed that GMP induces responses that are similar to those of glutamate, e.g., an outward current, an inward current, or a biphasic response. Our Ca2+ imaging results showed that applications of GMP, glutamate, and the mixture increased intracellular Ca2+ levels. Interestingly, both patch-clamp and Ca2+ imaging showed that some taste cells can respond to GMP and glutamate independently, indicating that glutamate and GMP likely activate different receptors. Simultaneous application of GMP and glutamate resulted in synergistic responses in a subset of cells; both response intensity and number of responding cells were increased. Most responses to GMP, as well as the synergy between GMP and glutamate, were suppressed by 8bromo-adenosine 3′,5′-cyclic monophosphate (8-bromo-cAMP) in patch-clamp recordings. Together, our results suggest that intracellular cAMP- and Ca2+-mediated pathways are involved in umami taste transduction for GMP and its synergistic responses with glutamate.
Regulation of Backpropagating Action Potentials in Mitral Cell Lateral Dendrites by A-Type Potassium Currents
Authors: Christie J. M. , Westbrook G. L.
Published: May 2006

Dendrodendritic synapses, distributed along mitral cell lateral dendrites, provide powerful and extensive inhibition in the olfactory bulb. Activation of inhibition depends on effective penetration of action potentials into dendrites. Although action potentials backpropagate with remarkable fidelity in apical dendrites, this issue is controversial for lateral dendrites. We used paired somatic and dendritic recordings to measure action potentials in proximal dendritic segments (0–200 μm from soma) and action potential-generated calcium transients to monitor activity in distal dendritic segments (200–600 μm from soma). Somatically elicited action potentials were attenuated in proximal lateral dendrites. The attenuation was not due to impaired access resistance in dendrites or to basal synaptic activity. However, a single somatically elicited action potential was sufficient to evoke a calcium transient throughout the lateral dendrite, suggesting that action potentials reach distal dendritic compartments. Block of A-type potassium channels ( I A) with 4-aminopyridine (10 mM) prevented action potential attenuation in direct recordings and significantly increased dendritic calcium transients, particularly in distal dendritic compartments. Our results suggest that I A may regulate inhibition in the olfactory bulb by controlling action potential amplitudes in lateral dendrites.
Fatigue of Paralyzed and Control Thenar Muscles Induced by Variable or Constant Frequency Stimulation
Authors: Thomas Christine K. , Griffin Lisa , Godfrey Sharlene , Ribot-Ciscar Edith , Butler Jane E.
Published: May 2006

Muscles paralyzed by chronic (>1 yr) spinal cord injury fatigue readily. Our aim was to evaluate whether the fatigability of paralyzed thenar muscles ( n = 10) could be reduced by the repeated delivery of variable versus constant frequency pulse trains. Fatigue was induced in four ways. Intermittent supramaximal median nerve stimulation (300-ms-duration trains) was delivered at 1) constant high frequency (13 pulses at 40 Hz each second for 2 min); 2) variable high frequency (each second for 2 min). The first two intervals of each variable frequency train were 5 and 20 ms. The remaining pulses were evenly distributed in time across 275 ms. The number of pulses varied for each subject such that the force time integral in the unfatigued state matched that evoked by a constant 40-Hz train; 3) constant low frequency (7 pulses at 20 Hz each second for 4 min); and 4) variable low frequency (each second for 4 min). The pulse pattern was the same as that for variable high frequency except that the force-time integral was matched to that produced by the constant low-frequency stimulation. These same experiments were performed on the thenar muscles of five able-bodied control subjects. The variable high-frequency trains used to fatigue paralyzed and control muscles had an average (± SE) of 12 ± 2 and 10 ± 1 pulses, respectively. Variable low-frequency trains had 7 ± 1 and 6 ± 1 pulses, respectively. Significant mean force declines of comparable magnitude (to 20–25% initial fatigue force or to 13–21% initial 50 Hz force) were seen in paralyzed muscles with all four stimulation protocols. The force reductions in paralyzed muscles were always accompanied by significant increases in half-relaxation time and decreases in force-time integral, irrespective of the stimulation protocol. Significant force decreases also occurred in control muscles during each fatigue test. Again, these force declines were similar whether constant or variable pulse patterns were used at high or low frequencies (to 40–60% initial fatigue force or to 29–36% initial 50 Hz force). The force reductions in control muscles were significantly less than those seen in paralyzed muscles, except when constant high-frequency stimulation was used. The variations in stimulation frequency, pulse pattern, and pulse number used in this study therefore had little influence on thenar muscle fatigue in control subjects or in spinal cord–injured subjects with chronic paralysis.
PKA and PKC Enhance Excitatory Synaptic Transmission in Human Dentate Gyrus
Authors: Chen Huan-Xin , Roper Steven N.
Published: May 2006

cAMP-dependent protein kinase (PKA) and protein kinase C (PKC) are two major modulators of synaptic transmission in the CNS but little is known about how they affect synaptic transmission in the human CNS. In this study, we used forskolin, a PKA activator, and phorbol ester, a PKC activator, to examine the effects of these kinases on synaptic transmission in granule cells of the dentate gyrus in human hippocampal slices using whole-cell recording methods. We found that both forskolin and phorbol ester increased the frequency of spontaneous and miniature excitatory postsynaptic currents (sEPSCs and mEPSCs) but left the amplitude unaffected. Inactive forskolin and phorbol ester had no effect on sEPSCs in human dentate granule cells. Prior application of forskolin occluded the effects of phorbol ester on mEPSC frequency. Tetanic stimulation applied to the perforant path induced short-term depression in dentate gyrus granule cells. Both forskolin and phorbol ester significantly enhanced this short-term depression. Taken together, these results demonstrate that PKA and PKC are involved in up-regulation of excitatory synaptic transmission in human dentate granule cells, primarily by presynaptic mechanisms. In addition, the occlusion experiments suggest that the two kinases may share a common signal pathway.
Corticocortical Inhibition of Peripheral Inputs Within Primary Somatosensory Cortex: The Role of GABAA and GABAB Receptors
Authors: Chowdhury S. A. , Rasmusson D. D.
Published: May 2006

A conditioning-test pulse paradigm was used in combination with microiontophoresis to examine the corticocortical modulation of somatosensory processing. Single-cell recordings were made in the glabrous digit representation of primary somatosensory (S1) cortex in anesthetized raccoons. Test stimulation of the periphery (the on-focus digit) was preceded by conditioning stimulation of the cortical area that represents an adjacent digit at interstimulus intervals ranging from 5 to 200 ms. An early and prolonged inhibitory modulation was produced in most of the 61 neurons examined, and an early facilitation followed by inhibition was produced in about one-third of the cells. Microiontophoretic administration of a potent GABAB receptor antagonist, CGP 55845, blocked the inhibition and in many cases revealed a facilitation of the sensory response. Microiontophoretic administration of a GABAA receptor antagonist, gabazine, blocked inhibition at short interstimulus intervals and reduced the longer inhibition by half. These results indicate that connections between glabrous digit representations within S1 cortex produce predominantly inhibitory modulation of sensory input and that both GABAA and GABAB receptors contribute to this modulation. The relevance of these connections to the effects of peripheral nerve injury and subsequent reorganization is discussed.
Slow Periodic Events and Their Transition to Gamma Oscillations in the Entorhinal Cortex of the Isolated Guinea Pig Brain
Authors: Dickson Clayton T. , Biella Gerardo , de Curtis Marco
Published: May 2006

Slow (<1 Hz) periodic activity is a distinctive discharge pattern observed in different cortical and sub-cortical structures during sleep and anesthesia. By performing field and cellular recordings, we demonstrated that slow periodic events (0.02–0.4 Hz) are spontaneously generated in the entorhinal cortex of the in vitro isolated whole brain of the guinea pig. These events were characterized by gradually developing runs of low-amplitude (50–300 μV), high-frequency (25–70 Hz) oscillations superimposed on a slow potential that lasted 1–3 s. Both slow and fast components showed a phase reversal in the superficial layers. In layer II-III entorhinal neurons, the slow periodic events correlated to a slowly developing depolarizing envelope capped by subthreshold membrane potential oscillations and action potential discharge. Slow periodic field events propagated tangentially across the entorhinal cortex and could be triggered by stimulation of superficial associative fibers, suggesting that they were generated by and propagated via network interactions in the superficial layers. Slow periodic events were reversibly abolished by muscarinic excitation elicited by carbachol (50 μM) that promoted intracellular membrane potential depolarization associated with continuous fast oscillatory activity in the gamma frequency range. These results suggest that, as proposed in vivo, activity changes in the entorhinal cortex of the in vitro isolated guinea-pig brain reflect different activation states that are under cholinergic control.
Measuring V1 Receptive Fields Despite Eye Movements in Awake Monkeys
Authors: Read Jenny C. A. , Cumming Bruce G.
Published: May 2006

One difficulty with measuring receptive fields in the awake monkey is that even well-trained animals make small eye movements during fixation. These complicate the measurement of receptive fields by blurring out the region where a response is observed, causing underestimates of the ability of individual neurons to signal changes in stimulus position. In simple cells, this blurring may severely disrupt estimates of receptive field structure. An accurate measurement of eye movements would allow correction of this blurring. Scleral search coils have been used to provide such measurements, although little is known about their accuracy. We have devised a range of approaches to address this issue: implanting two coils into a single eye, exploiting the small size of V1 receptive fields and developing maximum-likelihood fitting techniques to extract receptive field parameters in the presence of eye movements. All our investigations lead to the same conclusion: our scleral search coils (which were not sutured to the globe) are subject to an error of approximately the same magnitude as the small eye movements which occur during fixation: SD ∼ 0.1°. This error is large enough to explain the SD of measured vergence in the absence of any real changes in vergence state. This, and a variety of other arguments, indicate that the real variation in vergence is much smaller than coil measurements suggest. These results suggest that monkeys, like humans, maintain very stable vergence. The error has a slower time course than fixational eye movements so that search coils report the difference in eye position between two consecutive trials more accurately than the eye position itself on either trial. Receptive field estimates are unlikely to be improved by assuming the coil record is veridical and correcting for eye position accordingly. However, receptive field parameters can reliably be determined by a fitting technique that allows for eye movements. It is possible that suturing coils to the globe reduces the artifacts, but no method has been available to demonstrate this. These receptive field measurements provide a general means by which the reliability of eye-position measurements can be assessed.
An Information Theoretic Approach to the Contributions of the Firing Rates and the Correlations Between the Firing of Neurons
Authors: Rolls Edmund T. , Franco Leonardo , Aggelopoulos Nicholas C. , Reece Steven
Published: May 2006

To analyze the extent to which populations of neurons encode information in the numbers of spikes each neuron emits or in the relative time of firing of the different neurons that might reflect synchronization, we developed and analyzed the performance of an information theoretic approach. The formula quantifies the corrections to the instantaneous information rate that result from correlations in spike emission between pairs of neurons. We showed how these cross-cell terms can be separated from the correlations that occur between the spikes emitted by each neuron, the auto-cell terms in the information rate expansion. We also described a method to test whether the estimate of the amount of information contributed by stimulus-dependent synchronization is significant. With simulated data, we show that the approach can separate information arising from the number of spikes emitted by each neuron from the redundancy that can arise if neurons have common inputs and from the synergy that can arise if cells have stimulus-dependent synchronization. The usefulness of the approach is also demonstrated by showing how it helps to interpret the encoding shown by neurons in the primate inferior temporal visual cortex. When applied to a sample dataset of simultaneously recorded inferior temporal cortex neurons, the algorithm showed that most of the information is available in the number of spikes emitted by each cell; that there is typically just a small degree (approximately 12%) of redundancy between simultaneously recorded inferior temporal cortex (IT) neurons; and that there is very little gain of information that arises from stimulus-dependent synchronization effects in these neurons.
Brain Stem Pursuit Pathways: Dissociating Visual, Vestibular, and Proprioceptive Inputs During Combined Eye-Head Gaze Tracking
Authors: Roy Jefferson E. , Cullen Kathleen E.
Published: May 2006

Eye-head (EH) neurons within the medial vestibular nuclei are thought to be the primary input to the extraocular motoneurons during smooth pursuit: they receive direct projections from the cerebellar flocculus/ventral paraflocculus, and in turn, project to the abducens motor nucleus. Here, we recorded from EH neurons during head-restrained smooth pursuit and head-unrestrained combined eye-head pursuit (gaze pursuit). During head-restrained smooth pursuit of sinusoidal and step-ramp target motion, each neuron's response was well described by a simple model that included resting discharge (bias), eye position, and velocity terms. Moreover, eye acceleration, as well as eye position, velocity, and acceleration error (error = target movement – eye movement) signals played no role in shaping neuronal discharges. During head-unrestrained gaze pursuit, EH neuron responses reflected the summation of their head-movement sensitivity during passive whole-body rotation in the dark and gaze-movement sensitivity during smooth pursuit. Indeed, EH neuron responses were well predicted by their head- and gaze-movement sensitivity during these two paradigms across conditions (e.g., combined eye-head gaze pursuit, smooth pursuit, whole-body rotation in the dark, whole-body rotation while viewing a target moving with the head (i.e., cancellation), and passive rotation of the head-on-body). Thus our results imply that vestibular inputs, but not the activation of neck proprioceptors, influence EH neuron responses during head-on-body movements. This latter proposal was confirmed by demonstrating a complete absence of modulation in the same neurons during passive rotation of the monkey's body beneath its neck. Taken together our results show that during gaze pursuit EH neurons carry vestibular- as well as gaze-related information to extraocular motoneurons. We propose that this vestibular-related modulation is offset by inputs from other premotor inputs, and that the responses of vestibuloocular reflex interneurons (i.e., position-vestibular-pause neurons) are consistent with such a proposal.
Adaptation to Stable and Unstable Dynamics Achieved By Combined Impedance Control and Inverse Dynamics Model
Authors: Franklin David W. , Osu Rieko , Burdet Etienne , Kawato Mitsuo , Milner Theodore E.
Published: May 2006

This study compared adaptation in novel force fields where trajectories were initially either stable or unstable to elucidate the processes of learning novel skills and adapting to new environments. Subjects learned to move in a null force field (NF), which was unexpectedly changed either to a velocity-dependent force field (VF), which resulted in perturbed but stable hand trajectories, or a position-dependent divergent force field (DF), which resulted in unstable trajectories. With practice, subjects learned to compensate for the perturbations produced by both force fields. Adaptation was characterized by an initial increase in the activation of all muscles followed by a gradual reduction. The time course of the increase in activation was correlated with a reduction in hand-path error for the DF but not for the VF. Adaptation to the VF could have been achieved solely by formation of an inverse dynamics model and adaptation to the DF solely by impedance control. However, indices of learning, such as hand-path error, joint torque, and electromyographic activation and deactivation suggest that the CNS combined these processes during adaptation to both force fields. Our results suggest that during the early phase of learning there is an increase in endpoint stiffness that serves to reduce hand-path error and provides additional stability, regardless of whether the dynamics are stable or unstable. We suggest that the motor control system utilizes an inverse dynamics model to learn the mean dynamics and an impedance controller to assist in the formation of the inverse dynamics model and to generate needed stability.
Imagery of Voluntary Movement of Fingers, Toes, and Tongue Activates Corresponding Body-Part-Specific Motor Representations
Authors: Ehrsson H. Henrik , Geyer Stefan , Naito Eiichi
Published: May 2006

We investigate whether imagery of voluntary movements of different body parts activates somatotopical sections of the human motor cortices. We used functional magnetic resonance imaging to detect the cortical activity when 7 healthy subjects imagine performing repetitive (0.5-Hz) flexion/extension movements of the right fingers or right toes, or horizontal movements of the tongue. We also collected functional images when the subjects actually executed these movements and used these data to define somatotopical representations in the motor areas. In this study, we relate the functional activation maps to cytoarchitectural population maps of areas 4a, 4p, and 6 in the same standard anatomical space. The important novel findings are 1) that imagery of hand movements specifically activates the hand sections of the contralateral primary motor cortex (area 4a) and the contralateral dorsal premotor cortex (area 6) and a hand representation located in the caudal cingulate motor area and the most ventral part of the supplementary motor area; 2) that when imagining making foot movements, the foot zones of the posterior part of the contralateral supplementary motor area (area 6) and the contralateral primary motor cortex (area 4a) are active; and 3) that imagery of tongue movements activates the tongue region of the primary motor cortex and the premotor cortex bilaterally (areas 4a, 4p, and 6). These results demonstrate that imagery of action engages the somatotopically organized sections of the primary motor cortex in a systematic manner as well as activating some body-part-specific representations in the nonprimary motor areas. Thus the content of the mental motor image, in this case the body part, is reflected in the pattern of motor cortical activation.
Human Ocular Pursuit During the Transient Disappearance of a Visual Target
Authors: Bennett Simon J. , Barnes Graham R.
Published: May 2006

During the course of pursuing a moving target there are often periods of transient disappearance as it moves behind objects and surfaces. In experimental settings, eye velocity decays rapidly on the extinction of a moving target. However, eye velocity does not decay to zero if there is an expectation the target will reappear further along its trajectory. Increasing eye velocity to coincide with target reappearance could minimize the developing velocity error, but it remains to be empirically verified whether this can be achieved. The aim of the present study was to examine the influence of stimulus predictability, target velocity, and interstimulus interval (ISI) on ocular pursuit during the transient disappearance of a visual target. We confirmed that subjects ( n = 9) did not maintain eye velocity close to target velocity for the duration of the ISI. In general, after an initial reduction in eye velocity the majority of subjects ( n = 7) exhibited a significant increase before target reappearance. The timing of the velocity increase was not influenced by target velocity, stimulus predictability, or ISI. Consequently, for the 900-ms ISI the increase occurred too early and the eye was decelerating at the moment of target reappearance. These results are consistent with a reduction in gain being applied to the visuomotor drive when the target disappeared, followed by a reactivation in expectation of target reappearance. We modeled this process such that gain was modulated within a reafferent feedback system, hence preserving its output in the absence of negative visual feedback and enabling an anticipatory increase in eye velocity before expected target reappearance.
Functional Significance of Cannabinoid-Mediated, Depolarization-Induced Suppression of Inhibition (DSI) in the Hippocampus
Authors: Hampson Robert E. , Zhuang Shou-yuan , Weiner Jeff L. , Deadwyler Sam A.
Published: May 2006

A number of recent studies have demonstrated that a well-known form of short-term plasticity at hippocampal GABAergic synapses, called depolarization-induced suppression of inhibition (DSI), is in fact mediated by the retrograde actions of endocannabinoids released in response to depolarization of the postsynaptic cells. These studies suggest that endogenous cannabinoids may play an important role in regulating inhibitory tone in the mammalian CNS. Despite the widespread interest and potential physiological importance of DSI, many questions regarding the physiological relevance of DSI remain. To that end, this study set out to define the specific limiting conditions that could elicit DSI at GABAergic synapses in CA1 hippocampal pyramidal neurons and to determine if DSI could be elicited with pulse trains that mimic hippocampal cell-firing patterns that occur in vivo. Whole cell recordings from hippocampal neurons under voltage-clamp configuration were made in rat hippocampal slices. Spontaneous and evoked γ-aminobutyric acid-A (GABAA) receptor-mediated inhibitory postsynaptic currents (sIPSCs and eIPSCs, respectively) were recorded prior to and following depolarization of CA1 hippocampal pyramidal cells. Depolarizing voltage pulses were shaped to evoke currents in QX-314-treated cells similar to those accompanying single spontaneous voltage-clamped action potentials recorded from the soma. Attempts were made to elicit DSI with trains of these pulses that mimicked hippocampal cell firing patterns in vivo, for instance, when animals traverse place fields or are performing a short-term memory task. DSI could not be elicited by such pulse trains or by a number of other combinations of behaviorally specific firing parameters. The minimum duration of depolarization necessary to elicit DSI in hippocampal neurons determined by paired-pulse manipulation was 50 –75 ms at a critical interval of 20 –30 ms between pulse pairs. Under the conditions tested, the normal firing patterns of hippocampal neurons that occur in vivo do not appear to elicit DSI.
Presence of Ca2+-Dependent K+Channels in Chemosensory Cilia Support a Role in Odor Transduction
Authors: Delgado Ricardo , Saavedra M. Verónica , Schmachtenberg Oliver , Sierralta Jimena , Bacigalupo Juan
Published: May 2006

Olfactory receptor neurons (ORNs) respond to odorants with changes in the action potential firing rate. Excitatory responses, consisting of firing increases, are mediated by a cyclic AMP cascade that leads to the activation of cationic nonselective cyclic nucleotide-gated (CNG) channels and Ca2+-dependent Cl–(ClCa) channels. This process takes place in the olfactory cilia, where all protein components of this cascade are confined. ORNs from various vertebrate species have also been shown to generate inhibitory odor responses, expressed as decreases in action potential discharges. Odor inhibition appears to rely on Ca2+-dependent K+(KCa) channels, but the underlying transduction mechanism remains unknown. If these channels are involved in odor transduction, they are expected to be present in the olfactory cilia. We found that a specific antibody against a large conductance KCarecognized a protein of approximately 116 kDa in Western blots of purified rat olfactory ciliary membranes. Moreover, the antibody labeled ORN cilia in isolated ORNs from rat and toad ( Caudiverbera caudiverbera). In addition, single-channel recordings from inside-out membrane patches excised from toad chemosensory cilia showed the presence of 4 different types of KCachannels, with unitary conductances of 210, 60, 12, and 29 and 60 pS, high K+-selectivity, and Ca2+sensitivities in the low micromolar range. Our work demonstrates the presence of K+channels in the ORN cilia and supports their participation in odor transduction.
Functional Architecture of Eye Position Gain Fields in Visual Association Cortex of Behaving Monkey
Authors: Siegel Ralph M. , Raffi Milena , Phinney Raymond E. , Turner Jessica A. , Jandó Gábor
Published: May 2006

In the behaving monkey, inferior parietal lobe cortical neurons combine visual information with eye position signals. However, an organized topographic map of these neurons' properties has never been demonstrated. Intrinsic optical imaging revealed a functional architecture for the effect of eye position on the visual response to radial optic flow. The map was distributed across two subdivisions of the inferior parietal lobule, area 7a and the dorsal prelunate area, DP. Area 7a contains a representation of the lower eye position gain fields while area DP represents the upper eye position gain fields. Horizontal eye position is represented orthogonal to the vertical eye position across the medial lateral extents of the cortices. Similar topographies were found in three hemispheres of two monkeys; the horizontal and vertical gain field representations were not isotropic with a greater modulation found with the vertical. Monte Carlo methods demonstrated the significance of the maps, and they were verified in part using multiunit recordings. The novel topographic organization of this association cortex area provides a substrate for constructing representations of surrounding space for perception and the guidance of motor behaviors.
Structural Aspects of Postnatal Lung Development – Alveolar Formation and Growth
Authors: Burri Peter H.
Published: May 2006

The human lung is born with a fraction of the adult complement of alveoli. The postnatal stages of human lung development comprise an alveolar stage, a stage of microvascular maturation, and very likely a stage of late alveolarization. The characteristic structural features of the alveolar stage are well known; they are very alike in human and rat lungs. The bases for alveolar formation are represented by immature interairspace walls with two capillary layers with a central sheet of connective tissue. Interalveolar septa are formed by folding up of one of the two capillary layers. In the alveolar stage, alveolar formation occurs rapidly and is typically very conspicuous in both species; it has therefore been termed ‘bulk alveolarization’. During and after alveolarization the septa with double capillary networks are restructured to the mature form with a single network. This happens in the stage of microvascular maturation. After these steps the lung proceeds to a phase of growth during which capillary growth by intussusception plays an important role in supporting gas exchange. In view of reports that alveoli are added after the stage of microvascular maturation, the question arises whether the present concept of alveolar formation needs revision. On the basis of morphological and experimental findings we can state that mature lungs contain all the features needed for ‘late alveolarization’ by the classical septation process. Because of the high plasticity of the lung tissues, late alveolarization or some forms of compensatory alveolar formation may be considered for the human lung.
Plasminogen Activator Inhibitor-1 Deficiency Has Renal Benefits but Some Adverse Systemic Consequences in Diabetic Mice
Authors: Collins Sarah J. , Alexander Shannon L. , Lopez-Guisa Jesus M. , Cai Xiaohe , Maruvada Ravi , Chua Streamson C. , Zhang Guoqiang , Okamura Daryl M. , Matsuo Shunya , Eddy Allison A.
Published: May 2006

Background:Elevated plasma levels of plasminogen activator inhibitor-1 (PAI-1) are observed in patients with obesity, hypertension and diabetes, and several observations suggest that PAI-1 mediates diabetic vascular complications. Although increased intrarenal expression of PAI-1 is also a feature of diabetic nephropathy, evidence that PAI-1 plays a primary pathogenetic role in the renal pathology is lacking. Methods: This study was designed to investigate the renal effects of genetic PAI-1 deficiency in db/db mice with obesity, hyperinsulinemia and hyperglycemia. For comparison the effects of PAI-1 deficiency were also examined in a cohort of mice with insulin-deficient streptozotocin (STZ)-induced diabetes. The findings are reported for 4 study groups at 8 months of age: PAI-1+/+ controls, PAI-1+/+ diabetics, PAI-1–/– controls and PAI-1–/– diabetics. Results: PAI-1 deficiency had an unexpected negative impact on the db/db mice. Overall 33% of the diabetic mice died prematurely, and 63% of the db/db PAI-1–/– males had an obese body habitus but were runts. The final analyses were limited to the female db/db mice. Several nephropathy parameters were improved in the db/db PAI-1–/– group compared to the db/db PAI-1+/+ group including: albumin-to-creatinine ratios (57 ± 45 vs. 145 ± 71 µg/mg ×10), change in glomerular extracellular matrix (ECM) area (decrease of 10% compared to controls vs. an increase of 31%) and increased total kidney collagen (47% increased vs. 96% in the PAI-1+/+ diabetics). The serum glucose levels were 15–25% lower in the PAI-1–/– nondiabetic control groups and remained lower in the db/dbPAI-1–/– mice. The STZ study was performed in males. None of the mice developed a runted phenotype or died prematurely. After diabetes of 6 months’ duration changes in glomerular ECM area (–15 vs. +64%) and total kidney collagen (+8 vs. +40%) were lower in the PAI-1–/– mice compared to the PAI-1+/+ mice. The serum cholesterol levels were significantly lower in the PAI-1–/– mice, both controls (47 ± 3 vs. 53 ± 10 mg/dl) and diabetics (48 ± 3 vs. 74 ± 9 mg/dl). Conclusion: These data suggest a direct role for PAI-1 in renal matrix expansion and metabolic control in diabetes, but they also highlight important adverse outcomes that include male runting and premature death in mice with diabetes due to an inactive leptin receptor.
Pioglitazone Prevents Acute and Chronic Cardiac Allograft Rejection
Authors: Kosuge Hisanori , Haraguchi Go , Koga Noritaka , Maejima Yasuhiro , Suzuki Jun-ichi , Isobe Mitsuaki
Published: May 2006

Background—

Peroxisome proliferator–activated receptor-γ plays an important role in regulating inflammation. Although cardiac transplantation is an established therapy for patients with end-stage heart disease, allograft rejection is a major concern for long-term survival. We investigated the role of pioglitazone in acute and chronic rejection in a murine cardiac transplantation model.

Methods and Results—

We performed heterotopic murine cardiac transplantation in total allomismatch or major histocompatibility complex class II–mismatched combinations. Recipient mice were given standard chow or chow containing pioglitazone (3 mg · kg
−1
· d
−1
) beginning 1 day before cardiac transplantation. In acute rejection, animals given pioglitazone showed significantly longer cardiac allograft survival than control mice (mean survival time, 34.6±7.8 versus 8.4±0.4 days;
P
<0.003). Treatment with pioglitazone significantly suppressed graft expression of interferon-γ and monocyte chemoattractant protein-1. In chronic rejection, neointimal hyperplasia was significantly lower in allografts from mice treated with pioglitazone (luminal occlusion, 25.1±8.8%) than in those from control mice (65.8±7.3%,
P
<0.001). Pioglitazone-treated allografts showed significantly reduced expression of interferon-γ, interleukin-10, and monocyte chemoattractant protein-1. We performed mixed lymphocyte reactions and in vitro proliferation assays of smooth muscle cells. Addition of pioglitazone to mixed lymphocyte reactions inhibited proliferation of T cells. Smooth muscle cells showed significant proliferation when cocultured with activated splenocytes. This proliferation was significantly inhibited by the addition of pioglitazone (1 μmol/L).

Conclusions—

Pioglitazone prolongs allograft survival and attenuates neointimal hyperplasia through the suppression of proliferation of smooth muscle cells. Pioglitazone may be a novel means to prevent acute and chronic allograft rejection.
The Effects of Interior Design on Communication and Impressions of a Counselor in a Counseling Room
Authors: Miwa Yoshiko , Hanyu Kazunori
Published: May 2006

This study aimed to investigate effects of the interior design of a counseling room on participants' self-disclosure and impressions of a counselor. The authors examined the effects of lighting and decorations. It tested four conditions crossing decorations (with or without home-like decorations) and type of lighting (bright or dim). Eighty undergraduate students (clients) were randomly assigned to one of the conditions and individually underwent a structured interview with an interviewer (a counselor) and then completed a questionnaire. The results showed that dim lighting yielded more pleasant and relaxed feelings, more favorable impressions of the interviewer, and more self-disclosure than did the bright lighting. However, the authors found no predominant pattern of the decorations. Thus, the pleasant and relaxed feelings related to dim lighting may well enhance the perceived attractiveness of a counselor and self-disclosure from clients. The results imply that interior design could influence communication and other relationships in counseling rooms.
Cultural Models of Nature and Society
Authors: Ignatow Gabriel
Published: May 2006

Social scientists have long debated the factors influencing public concern for the natural environment. This study attempts to contribute to this debate by arguing that environmental concern is shaped by both “spiritual” and “ecological” cultural models of nature-society relations and that by distinguishing between these two, we can better recognize the social sources of variation in concern for the environment. An analysis of questionnaire data from 21 nations from the 1993 International Social Survey Program using ordinary least squares regression models shows that spiritual and ecological environmental worldviews have different social bases. Education generally positively predicts the latter but not the former. Patterns of national differences are noteworthy as well. Thus, conceptualizing public concern for the environment in terms of distinct cultural models may be more revealing than focusing on environmental concern as such.
Seeking Restorative Experiences
Authors: Gulwadi Gowri Betrabet
Published: May 2006

Teacher stress and coping research and restorative environments research were converged in this study to explore how elementary school teachers in Chicago seek out everyday places in their milieu to implement restorative coping strategies. Seventy-one survey responses revealed that teachers' spontaneous place choices are related to sources of stress and that the restorative potential of a place was related to its ability to support teachers'inward or outward coping strategies. Teachers implemented effective strategies in places such as home, nature, city places, third places, and church. The ways these places were experienced differed according to teachers' perceptions of frequency and type of stress and how the place enabled the inward or outward strategy as needed. Findings suggest directions for exploring restorative design interventions in teachers' environments, especially within school environments.
Visualizing Neighborhood in Renaissance Florence
Authors: Burke Jill
Published: May 2006

The organization and decoration of chapels in the churches of Renaissance Florence have much to tell us about neighborhood relationships. Analysis of the church works committees and of the ownership of chapels in the Santo Spirito and Carmine churches reveals that administrative divisions were more important than proximity in determining which church the key families of the area chose to patronize. In both cases the allocation and decoration of chapels expressed local status relationships in visual form, yet the visual language of the two churches was fundamentally different. In Santo Spirito the new Renaissance style expressed the power and aspirations of a community elite. At the Carmine there was extensive neighborhood involvement in the decoration of chapels, sometimes in providing funding and sometimes in regulating their style. There the older style expressed the involvement of a less extensive but more socially diverse neighborhood.
Addressing Wealth in Renaissance Florence
Authors: Eckstein Nicholas A.
Published: May 2006

This article uses a source well known to historians (the Florentine tax census of 1427—the catasto) to carry out minute analysis of wealth, residence and occupation patterns in one working-class neighborhood, the gonfalone of the Green Dragon. The article demonstrates the gradations of wealth and occupational status that could occur within a relatively small urban area; thereafter it scrutinizes details beyond the scope of most similar studies for this period, at the level of the individual city block. At such high levels of magnification, the city appears as a complex entity that cannot be accommodated to standard generalizations that attempt to describe the ecology of the city as a whole. While it examines data from a single year, the article also reveals the information contained in the catasto as the product of historical change, and argues for further interdisciplinary study that may further enhance our knowledge of life within Florence's myriad, overlapping microcommunities.
Big Piero, the Empire of the Meadow, and the Parish of Santa Lucia
Authors: Rosenthal David
Published: May 2006

If neighborhood territories and networks reflected the strategies and lived experience of the wealthy and the powerful in Florence, they also were shaped and reshaped from below. Paying particular attention to the symbolic imagining and enactment of neighborhood in sixteenth-century Florence, this article traces the festive expressions of artisan communities in the form of “kingdoms” tied to local social worlds of parish, church, street, and occupation. It argues that expressions of solidarity—which involved both exclusion and inclusion—helped establish the political identity and rights of those communities in the civic realm and provided a basis for claims about the obligations of rulers and the powerful.
Empathy-Motivated Helping: The Moderating Role of Group Membership
Authors: Stürmer Stefan , Snyder Mark , Kropp Alexandra , Siem Birte
Published: May 2006

In this article, the authors present two laboratory experiments testing a group-level perspective on the role of empathy in helping. Experiment 1 tested the authors' predictions in an intercultural context of helping. Confirming their specific Empathy × Group Membership moderation hypothesis, empathy had a stronger effect on helping intentions when the helper and the target belonged to the same cultural group than when they belonged to different groups. Experiment 2 replicated these findings in a modified minimal group paradigm using laboratory-created groups. Moreover, this second experiment also provides evidence for the hypothesized psychological mechanisms underlying the empathy-(ingroup) helping relationship. Specifically, analyses in the ingroup condition confirmed that the strength of the empathy-(ingroup) helping relationship systematically varied as a function of perceived similarities among ingroup members. The general implications of these findings for empathy-motivated helping are discussed.
Ranks and Rivals: A Theory of Competition
Authors: Garcia Stephen M. , Tor Avishalom , Gonzalez Richard
Published: May 2006

Social comparison theories typically imply a comparable degree of competition between commensurate rivals who are competing on a mutually important dimension. However, the present analysis reveals that the degree of competition between such rivals depends on their proximity to a meaningful standard. Studies 1 to 3 test the prediction that individuals become more competitive and less willing to maximize profitable joint gains when they and their commensurate rivals are highly ranked (e.g., #2 vs. #3) than when they are not (e.g., #202 vs. #203). Studies 4 to 6 then generalize these findings, showing that the degree of competition also increases in the proximity of other meaningful standards, such as the bottom of a ranking scale or a qualitative threshold in the middle of a scale. Studies 7 and 8 further examine the psychological processes underlying this phenomenon and reveal that proximity to a standard exerts a direct impact on the basic unidirectional drive upward, beyond the established effects of commensurability and dimension relevance.
The Effect of Protective Equipment on Cervical Spine Alignment in Collegiate Lacrosse Players
Authors: Sherbondy Paul S. , Hertel Jay N. , Sebastianelli Wayne J.
Published: May 2006

Background

Contact sports place athletes at risk for cervical spine injury. Protective helmets and shoulder pads worn by football and ice hockey athletes alter cervical spine alignment. The effect of helmet and shoulder pads on neck alignment in lacrosse athletes is not known.

Hypothesis

Helmets and shoulder pads worn by lacrosse athletes alter cervical spine alignment.

Study Design

Controlled laboratory study.

Methods

Sagittal plane cervical spine alignment was evaluated in 16 uninjured male collegiate lacrosse players using computed tomography. Patients were immobilized in the supine position on a standard spine board. Testing was performed without equipment, with both helmet and shoulder pads in place, and with the helmet removed. Angular measurements of the cervical spine were made and analyzed.

Results

The presence of both the helmet and shoulder pads caused an increase in overall cervical extension (mean, 6°) compared with the absence of both pieces of equipment (P =. 002). Helmet removal alone resulted in a mean increase in cervical flexion of 4.7° in the upper cervical spine compared with the presence of both pieces of equipment (P =. 011). Compared with the absence of equipment, shoulder pads caused increased cervical flexion in the lower cervical spine (mean, 4.4°; P =. 036).

Conclusion

Protective equipment worn by lacrosse athletes causes statistically significant increases in cervical extension, and its removal causes statistically significant increases in cervical flexion. This alteration is different from that previously reported for protective equipment in football and ice hockey.

Clinical Relevance

The authors’ recommendation is that both lacrosse helmets and shoulder pads be left in place until they can be completely removed in a controlled fashion. The effect of external equipment on neck position is different for lacrosse compared with football and ice hockey.
People Who Have Their Tickets But Do Not Use Them
Authors: Brown Robert D. , Wedeking Justin
Published: May 2006

We reexamine the effects of the National Voter Registration Act (NVRA) legislation on aggregate participation rates in the states. We approach NVRA as working directly on registration, and only indirectly on turnout, and we argue that the most appropriate way to evaluate NVRA is to examine how it translates increased registration into turnout. Using Federal Election Commission/Electoral Assistance Commission and census data, we find that an unanticipated impact of NVRA has been to alter the long-standing empirical relationship between registration and turnout. Further analyses suggest this failure to transmit registration into turnout may, ironically, be the result of another success of NVRA—an increase in the relative equality of registrants. By encouraging lower income citizens to register, NVRA has helped create a pool of registered citizens less likely to vote. These findings have implications for discussions of NVRA and for the participation literature that views registration as a primary catalyst for turnout.
Radio Advertising in American Political Campaigns
Authors: Overby L. Marvin , Barth Jay
Published: May 2006

Although much research has been done on advertising in American political campaigns, virtually all has focused on the use of television. The dearth of work on radio advertising limits our ability to fully understand American electoral dynamics. More campaigns use radio than television, and there is reason to suspect that the narrowcasting that is possible with highly targeted radio ads may be substantively different from the campaign messages that are broadcast over the television airwaves. In this article, we use data from a survey of registered voters in Arkansas and Missouri during the 2002 election season to explore the dynamics of political advertising on the radio. We focus in particular on factors that influence exposure to radio ads, the public’s perceptions of the importance of these ads, and the impacts of exposure on the public’s perceptions of the quality of the democratic process in the United States.
National Intervention and the Diffusion of Policy Innovations
Authors: Karch Andrew
Published: May 2006

Scholars have long recognized that national activity influences both the substance and the timing of state policymaking. This article examines whether the content of national legislation affects the state-level enactment of policy innovations even if it does not mandate their adoption or provide a financial incentive for state lawmakers to enact them. It uses event history analysis on pooled, cross-sectional data to examine the diffusion of three innovations in human services policy: individual development accounts, family caps, and medical savings accounts. Its results suggest that national intervention affects the likelihood that state lawmakers will adopt an innovation by altering the strength of the obstacles that prevent innovation or by providing resources to help overcome these obstacles. National intervention that does not affect these determinants of innovation seems to have no significant effect on state officials’ decisions.