bluuebunny/crossref_metadata_2025 huggingface dataset:
Survival and arm abscission are linked to regional heterothermy in an intertidal sea star
Authors: Pincebourde Sylvain , Sanford Eric , Helmuth Brian
Published: May 2013

Body temperature is a more pertinent variable to physiological stress than ambient air temperature. Modeling and empirical studies on the impacts of climate change on ectotherms usually assume that body temperature within organisms is uniform. However, many ectotherms show significant within-body temperature heterogeneity. The relationship between regional heterothermy and the response of ectotherms to sublethal and lethal conditions remains underexplored. We quantified within-body thermal heterogeneity in an intertidal sea star (Pisaster ochraceus) during aerial exposure at low tide to examine the lethal and sublethal effects of temperatures of different body regions. In manipulative experiments, we measured the temperature of the arms and central disc, as well as survival and arm abscission under extreme aerial conditions. Survival was related strongly to central disc temperature. Arms were generally warmer than the central disc in individuals that survived aerial heating, but we found the reverse in those that died. When the central disc reached sublethal temperatures of 31–35°C, arms reached temperatures of 33–39°C, inducing arm abscission. The absolute temperature of individual arms was a poor predictor of arm abscission, but the arms lost were consistently the hottest at the within-individual scale. Therefore, the vital region of this sea star may remain below the lethal threshold under extreme conditions, possibly through water movement from the arms to the central disc and/or evaporative cooling, but at the cost of increased risk of arm abscission. Initiation of arm abscission seems to reflect a whole-organism response while death occurs as a result of stress acting directly on central disc tissues.
Sirenomelia in a Cameroonian woman: a case report and review of the literature
Authors: Morfaw Frederick LI , Nana Philip N
Published: May 2013

Sirenomelia is a rare congenital malformative disorder characterized by fusion of the lower limbs giving a characteristic mermaid-like appearance to the affected foetus. We report a case of sirenomelia occurring in a 19 year old Cameroonian woman following premature rupture of membranes and associated cord prolapse. This is the first documented case in this country. We highlight some of the cultural myths associated with this disorder and discuss our findings relative to the present literature and related controversies on its etiopathogenesis.
Blunting Damocles' Sword: A Longitudinal Model of Healthcare IT Impact on Malpractice Insurance Premium and Quality of Patient Care
Authors: Menon Nirup M. , Kohli Rajiv
Published: May 2013

Prior studies on the business value of information technology (IT) mainly focus on the impact of IT investments on productivity and firm profitability. Few have considered its implication on expected and actual product or service quality. This paper fills this gap by investigating the impact of past healthcare IT (HIT) expenditure on the malpractice insurance premium (MIP) and the moderating effect of past HIT expenditure on the relationship between past MIP and current quality of patient care in a longitudinal model. Based on archival panel data on costs, operations, and patient care outcomes of 66 hospitals in the U.S. state of Washington from 1998 to 2007, we find that past HIT expenditure is negatively associated with MIP, supporting our argument that HIT provides value that is anticipated by insurers and is captured by a change in MIP. We find that past HIT is positively associated with quality of patient care. We also find that past MIP is positively associated with quality of patient care, supporting the premise that hospitals respond to MIP by making risk mitigation efforts. However, we find that past HIT moderates this relationship negatively, suggesting a reliance on HIT at the expense of risk mitigation.
Research Note—Continued Participation in Online Innovation Communities: Does Community Response Matter Equally for Everyone?
Authors: Zhang Chen , Hahn Jungpil , De Prabuddha
Published: May 2013

In this study, we focus on the factors that influence online innovation community members' continued participation in the context of open source software development (OSSD) communities. Prior research on continued participation in online communities has primarily focused on social interactions among members and benefits obtained from these interactions. However, members of these communities often play different roles, which have been examined extensively, albeit in a separate stream of research. This study attempts to bridge these two streams of research by investigating the joint influence of community response and members' roles on continued participation. We categorize OSSD community members into users and modifiers and empirically examine the differential effects of community response across these roles. By analyzing a longitudinal data set of activities in the discussion forums of more than 300 OSSD projects, we not only confirm the positive influence of community response on members' continued participation but also find that community response is more influential in driving the continuance behavior of users than that of modifiers. In addition, this research highlights the importance of modifiers, a key subgroup of OSSD participants that has been largely overlooked by prior research.
Role of Dexmedetomidine for the Prevention and Treatment of Delirium in Intensive Care Unit Patients
Authors: Mo Yoonsun , Zimmermann Anthony E
Published: May 2013

OBJECTIVE:

To review recent clinical studies regarding the role of dexmedetomidine for prevention and treatment of delirium in intensive care unit (ICU) patients.

DATA SOURCES:

MEDLINE and PubMed searches (1988-Feburary 2013) were conducted, using the key words delirium, dexmedetomidine, Precedex, agitation, α-2 agonists, critical care, and intensive care. References from relevant articles were reviewed for additional information.

STUDY SELECTION AND DATA EXTRACTION:

Clinical trials comparing dexmedetomidine with other sedatives/analgesics or with antipsychotics for delirium were selected. Studies that evaluated the use of dexmedetomidine for sedation for more than 6 hours were included in this review.

DATA SYNTHESIS:

Dexmedetomidine is a highly selective α-2 receptor agonist that provides sedation, anxiolysis, and modest analgesia with minimal respiratory depression. Its mechanism of action is unique compared with that of traditional sedatives because it does not act on γ-aminobutyric acid receptors. In addition, dexmedetomidine lacks anticholinergic activity and promotes a natural sleep pattern. These pharmacologic characteristics may explain the possible antidelirium effects of dexmedetomidine. Eight clinical trials, including 5 double-blind randomized trials, were reviewed to evaluate the impact of dexmedetomidine on ICU delirium.

CONCLUSIONS:

Currently available evidence suggests that dexmedetomidine is a promising agent, not only for prevention but also for treatment of ICU-associated delirium. However, larger, well-designed trials are warranted to define the role of dexmedetomidine in preventing and treating delirium in the ICU.
Systematic Characterization of Myocardial Inflammation, Repair, and Remodeling in a Mouse Model of Reperfused Myocardial Infarction
Authors: Christia Panagiota , Bujak Marcin , Gonzalez-Quesada Carlos , Chen Wei , Dobaczewski Marcin , Reddy Anilkumar , Frangogiannis Nikolaos G.
Published: May 2013

Mouse models of myocardial infarction are essential tools for the study of cardiac injury, repair, and remodeling. Our current investigation establishes a systematic approach for quantitative evaluation of the inflammatory and reparative response, cardiac function, and geometry in a mouse model of reperfused myocardial infarction. Reperfused mouse infarcts exhibited marked induction of inflammatory cytokines that peaked after 6 hr of reperfusion. In the infarcted heart, scar contraction and chamber dilation continued for at least 28 days after reperfusion; infarct maturation was associated with marked thinning of the scar, accompanied by volume loss and rapid clearance of cellular elements. Echocardiographic measurements of end-diastolic dimensions correlated well with morphometric assessment of dilative remodeling in perfusion-fixed hearts. Hemodynamic monitoring was used to quantitatively assess systolic and diastolic function; the severity of diastolic dysfunction following myocardial infarction correlated with cardiomyocyte hypertrophy and infarct collagen content. Expression of molecular mediators of inflammation and cellular infiltration needs to be investigated during the first 72 hr, whereas assessment of dilative remodeling requires measurement of geometric parameters for at least four weeks after the acute event. Rapid initiation and resolution of the inflammatory response, accelerated scar maturation, and extensive infarct volume loss are important characteristics of infarct healing in mice.
Supplier Selection for Processes with Multiple Characteristics Based on Testing Capability Index Cpk
Authors: Pearn W. L. , Wu C. H.
Published: May 2013

Supplier selection is the problem which deals with comparing two processes and selecting a better one that has a higher process capability. In this article, the generalization CTpk index is employed to deal with this problem. The generalization CTpk index measures the overall yield for the processes with multiple independent quality characteristics. Based on the generalization CTpk index, a hypothesis testing with two phases is developed to determine whether or not new supplier is better. It allows one to select the supplier with better quality. A test statistic by division method and its corresponding sampling distribution are derived. For various process minimum requirements, magnitudes of the difference between the two processes, unequal sample sizes of two processes, and α-risk, the critical values of the tests are tabulated. An application example is presented to illustrate the practicality of the proposed approach. Practitioners can use the proposed method to make reliable decisions in supplier selection problem.
An Assessment of Gauge Repeatability and Reproducibility with Multiple Characteristics
Authors: Wang Fu-Kwun
Published: May 2013

Measurement system analysis plays an important role of many continuous improvement initiatives in the manufacturing industry. Measurement systems are commonly evaluated by performing a gauge repeatability and reproducibility (GRR) study. In some circumstances, manufacturing tests in a GRR study may have multiple characteristics with a multivariate normal distribution. To determine the preferred method for a GRR analysis, multivariate analysis of variance (MANOVA) and principal component analysis (PCA) are applied to data taken from two real cases. Three performance measures [precision to tolerance ratio (PTRM), the percentage of repeatability and reproducibility (%RRM), and signal-to-noise ratio (SNRM)] are used to evaluate the adequacy of the measurement process. The results show that the MANOVA method is suitable for a GRR study with multiple characteristics.
Evaluating Frictional Characteristics of Typical Wearing Course Mixtures in Louisiana
Authors: Wu Zhong , Yang Xiaoming , Lal Das Vivek , Mohammad Louay N.
Published: May 2013

In this study, the frictional characteristics of a number of Louisiana wearing course mixtures were evaluated through a suite of laboratory tests. Aggregates of different levels of micro-textures were used in the mix design. Asphalt concrete slab samples were prepared using a kneading compactor and were accelerated polished using a three-wheel polishing device developed by the National Center of Asphalt Technology for simulating the traffic-polishing effect on the surface texture of the pavement. After different numbers of polishing cycles, the frictional characteristics of asphalt concrete slabs were evaluated using a dynamic friction tester (DFT) and a circular texture meter (CTM). A comprehensive statistical analysis was conducted to investigate the effects of aggregate type and mix type on the frictional characteristics of the asphalt concrete mixtures. The international friction index F(60) values (calculated from the DFT and the CTM test results) were used to characterize the overall frictional performance of the asphalt concrete mixtures considered. The experimental results showed that aggregates with higher levels of micro-texture generally performed significantly better than those with lower levels of micro-texture in the DFT test. The open grade friction course and stone matrix asphalt showed better macro-textures than the Superpave mixtures in the CTM tests. A statistical grouping based on the terminal F(60) values of different mixtures showed that it is possible to achieve the same level of F(60) using different combinations of mix and aggregate types. This study demonstrates that blending low- and high-friction aggregates together can possibly produce an asphalt mixture with adequate field skid resistance.
Development of a New Testing Procedure for Performing Tensile Tests on Specimens with Sub-Millimetre Dimensions
Authors: Rathmayr Georg B. , Bachmaier Andrea , Pippan Reinhard
Published: May 2013

A new method to conduct tensile tests with specimens ranging from a few millimetres down to 100 μm is presented. The tensile specimens are fabricated using a newly developed water-cooled circular grinding process that guarantees a high-accuracy geometry by keeping the fabrication-related material change to a minimum. Furthermore, the grinding tool is equipped with a mechanical polishing unit to make well-polished surfaces. Besides the specimen fabrication, the test setup is modified to allow a specimen related displacement measurement. This image-based system does not require any additional specimen markings and enables the evaluation of true stress, true strain, and the reduction in area. The whole method is successfully demonstrated for different types of metals ranging from ductile nickel to very brittle tungsten. In addition to the quality of the tensile test in this specimen size range, another advantage is the enormous reduced time for specimen fabrication and testing.
Accelerated Slam Testing of Vehicle Door Plate Module Using Vibration Exciter
Authors: Kim Chan-Jung , Lee Bong-Hyun , June Kang Yeon
Published: May 2013

Slam testing is an important test for evaluating the fatigue resistance of a door plate module prior to its delivery to the car manufacturer. In such testing, one experimental specimen is subjected to more than 8 days of continuous testing. In this paper, a vibration testing method is proposed that is intended to replace the conventional swing-type slam testing of a door plate module. The method is based on the concept of duplicating the same failure mode at the clamping part of the glass in a door, where the stress is concentrated. After a review of the feasibility test performed with a multi-axial vibration simulator, a similarity test for a door module was developed that uses a uni-axial vibration exciter that required the door glass to be exposed to a critical spectrum of vibration for less than 2 h. The validity of the proposed testing method was demonstrated by comparing the failure modes of both the conventional and the proposed slam tests.
A Solution for Estimating the Tensile Yield Strength From Small Specimens
Authors: Mak Jonathan , Wei Tao , Wuhrer Richard , Yeung Wing , Heness Greg , Di Zhang
Published: May 2013

The small punch test is an innovative test that utilises small disc-shaped specimens to assess the mechanical behaviour of materials. The main advantage is the relatively small specimen size. In this article, a modified analytical solution for the small punch maximum bend strength is proposed that is based on classical plate theory. A clear linear relationship is observed between the tensile yield strength σYS and the small punch maximum bend strength σy for both alloys and metal matrix composites.
Monitoring of Vertical Movement in a Four-Story Wood-Frame Building in Coastal British Columbia
Authors: Wang Jieying , Ni Chun , Mustapha Gamal
Published: May 2013

Vertical movement and lumber moisture content (MC) were monitored during the construction of a four-story wood frame residential building in the winter of 2010–2011 in coastal British Columbia, Canada. The work was part of a long-term study to assemble field performance information and validate movement prediction methods to assist in the design of five- and six-story wood frame buildings. The MC readings of dimensional lumber generally remained around 20 % on average before the building was completely protected from rain with its roof and wall sheathing membrane under rainy construction conditions. With the data collection started when the roof sheathing was installed and continued into occupancy of the building, the vertical movement was found to occur during the process of wood drying and the installation of non-structural elements such as drywall and cladding etc., which increased the local loads. The total movement amount, contributed by wood shrinkage, gap closure (settlement), and other factors, reached about 34 mm at an exterior wall, 43 mm at an interior hallway shear wall, and 45 mm at an interior partition wall, after a total monitoring period of 17 months. These values were fairly comparable to the values predicted from wood shrinkage alone for this building.
Long-Term Depression of Synaptic Kainate Receptors Reduces Excitability by Relieving Inhibition of the Slow Afterhyperpolarization
Authors: Chamberlain Sophie E.L. , Sadowski Josef H.L.P. , Teles-Grilo Ruivo Leonor M. , Atherton Laura A. , Mellor Jack R.
Published: May 2013

Kainate receptors (KARs) are ionotropic glutamate receptors that also activate noncanonical G-protein-coupled signaling pathways to depress the slow afterhyperpolarization (sAHP). Here we show that long-term depression of KAR-mediated synaptic transmission (KAR LTD) at rat hippocampal mossy fiber synapses relieves inhibition of the sAHP by synaptic transmission. KAR LTD is induced by high-frequency mossy fiber stimulation and natural spike patterns and requires activation of adenosine A2Areceptors. Natural spike patterns also cause long-term potentiation of NMDA receptor-mediated synaptic transmission that overrides the effects of KAR LTD on the cellular response to low-frequency synaptic input. However, KAR LTD is dominant at higher frequency synaptic stimulation where it decreases the cellular response by relieving inhibition of the sAHP. Thus we describe a form of glutamate receptor plasticity induced by natural spike patterns whose primary physiological function is to regulate cellular excitability.
Synaptic Zn2+Inhibits Neurotransmitter Release by Promoting Endocannabinoid Synthesis
Authors: Perez-Rosello Tamara , Anderson Charles T. , Schopfer Francisco J. , Zhao Yanjun , Gilad David , Salvatore Sonia R. , Freeman Bruce A. , Hershfinkel Michal , Aizenman Elias , Tzounopoulos Thanos
Published: May 2013

Although it is well established that many glutamatergic neurons sequester Zn2+within their synaptic vesicles, the physiological significance of synaptic Zn2+remains poorly understood. In experiments performed in a Zn2+-enriched auditory brainstem nucleus—the dorsal cochlear nucleus—we discovered that synaptic Zn2+and GPR39, a putative metabotropic Zn2+-sensing receptor (mZnR), are necessary for triggering the synthesis of the endocannabinoid 2-arachidonoylglycerol (2-AG). The postsynaptic production of 2-AG, in turn, inhibits presynaptic probability of neurotransmitter release, thus shaping synaptic strength and short-term synaptic plasticity. Zn2+-induced inhibition of transmitter release is absent in mutant mice that lack either vesicular Zn2+or the mZnR. Moreover, mass spectrometry measurements of 2-AG levels reveal that Zn2+-mediated initiation of 2-AG synthesis is absent in mice lacking the mZnR. We reveal a previously unknown action of synaptic Zn2+: synaptic Zn2+inhibits glutamate release by promoting 2-AG synthesis.
A Physical Constraint on Perceptual Learning: Tactile Spatial Acuity Improves with Training to a Limit Set by Finger Size
Authors: Wong Michael , Peters Ryan M. , Goldreich Daniel
Published: May 2013

In touch as in vision, perceptual acuity improves with training to an extent that differs greatly across people; even individuals with similar initial acuity may undergo markedly different improvement with training. What accounts for this variability in perceptual learning? We hypothesized that a simple physical characteristic, fingertip surface area, might constrain tactile learning, because previous research suggests that larger fingers have more widely spaced mechanoreceptors. To test our hypothesis, we trained 10 human participants intensively on a tactile spatial acuity task. During 4 d, participants completed 1900 training trials (38 50-trial blocks) in which they discriminated the orientation of square-wave gratings pressed onto the stationary index or ring finger, with auditory feedback provided to signal correct and incorrect responses. We progressively increased task difficulty by shifting to thinner groove widths whenever participants achieved ≥90% correct block performance. We took optical scans to measure surface area from the distal interphalangeal crease to the tip of the finger. Participants' acuity improved markedly on the trained finger and to a lesser extent on the untrained finger. Crucially, we found that participants' tactile spatial acuity improved toward a theoretical optimum set by their finger size; participants with worse initial performance relative to their finger size improved more with training, and posttraining performance was better correlated than pretraining performance with finger size. These results strongly support the hypothesis that tactile perceptual learning is limited by finger size. We suspect that analogous physical constraints on perceptual learning will be found in other sensory modalities.
Reduced Adult Hippocampal Neurogenesis and Working Memory Deficits in theDgcr8-Deficient Mouse Model of 22q11.2 Deletion-Associated Schizophrenia Can Be Rescued by IGF2
Authors: Ouchi Yasuo , Banno Yuya , Shimizu Yuko , Ando Shouta , Hasegawa Hitoki , Adachi Koichi , Iwamoto Takashi
Published: May 2013

DiGeorge syndrome chromosomal region 8 (Dgcr8), a candidate gene for 22q11.2 deletion-associated schizophrenia, encodes an essential component for microRNA (miRNA) biosynthesis that plays a pivotal role in hippocampal learning and memory. Adult neurogenesis is known to be important in hippocampus-dependent memory, but the role and molecular mechanisms of adult neurogenesis in schizophrenia remain unclear. Here, we show thatDgcr8heterozygosity in mice leads to reduced cell proliferation and neurogenesis in adult hippocampus, as well as impaired hippocampus-dependent learning. Several schizophrenia-associated genes were downregulated in the hippocampus ofDgcr8+/−mice, and one of them, insulin-like growth factor 2 (Igf2), rescued the proliferation of adult neural stem cells bothin vitroandin vivo. Furthermore, IGF2 improved the spatial working memory deficits inDgcr8+/−mice. These data suggest that defective adult neurogenesis contributes to the cognitive impairment observed in 22q11.2 deletion-associated schizophrenia and could be rectified by IGF2.
Spectral Context Affects Temporal Processing in Awake Auditory Cortex
Authors: Malone Brian J. , Beitel Ralph E. , Vollmer Maike , Heiser Marc A. , Schreiner Christoph E.
Published: May 2013

Amplitude modulation encoding is critical for human speech perception and complex sound processing in general. The modulation transfer function (MTF) is a staple of auditory psychophysics, and has been shown to predict speech intelligibility performance in a range of adverse listening conditions and hearing impairments, including cochlear implant-supported hearing. Although both tonal and broadband carriers have been used in psychophysical studies of modulation detection and discrimination, relatively little is known about differences in the cortical representation of such signals. We obtained MTFs in response to sinusoidal amplitude modulation (SAM) for both narrowband tonal carriers and two-octave bandwidth noise carriers in the auditory core of awake squirrel monkeys. MTFs spanning modulation frequencies from 4 to 512 Hz were obtained using 16 channel linear recording arrays sampling across all cortical laminae. Carrier frequency for tonal SAM and center frequency for noise SAM was set at the estimated BF for each penetration. Changes in carrier type affected both rate and temporal MTFs in many neurons. Using spike discrimination techniques, we found that discrimination of modulation frequency was significantly better for tonal SAM than for noise SAM, though the differences were modest at the population level. Moreover, spike trains elicited by tonal and noise SAM could be readily discriminated in most cases. Collectively, our results reveal remarkable sensitivity to the spectral content of modulated signals, and indicate substantial interdependence between temporal and spectral processing in neurons of the core auditory cortex.
Role of the Major Glutamate Transporter GLT1 in Nucleus Accumbens Core Versus Shell in Cue-Induced Cocaine-Seeking Behavior
Authors: Fischer Kathryn D. , Houston Alexander C.W. , Rebec George V.
Published: May 2013

Relapse to cocaine-seeking behavior requires an increase in nucleus accumbens (NAc) core glutamate transmission. Decreased expression of glutamate type I transporter (GLT1), which is responsible for >90% of glutamate clearance, occurs in the core of rats withdrawn from cocaine self-administration, while treatment with ceftriaxone, a β-lactam antibiotic previously shown to increase GLT1 expression and function in rodents, upregulates GLT1 and attenuates cue-induced cocaine reinstatement. Here, we tested the effects of increasing GLT1 expression on cue-induced cocaine seeking in rats exposed to either limited (2 h/d) or extended (6 h/d) cocaine access followed by short (2 d) or long (45 d) withdrawal periods. Treatment with ceftriaxone (200 mg/kg, i.p.) upregulated core GLT1 expression and attenuated cue-induced cocaine-seeking behavior only in rats exposed to long withdrawal periods, with a greater effect in the extended-access condition. Pearson's correlation revealed GLT1 expression in core to be inversely correlated with cue-induced cocaine-seeking behavior. To localize the effects of GLT1 upregulation within NAc, we tested the hypothesis that blockade of GLT1 in NAc core, but not shell, would reverse the ceftriaxone-mediated effect. Rats withdrawn from cocaine self-administration were treated with the same dose of ceftriaxone followed by intracore or intrashell infusions of one of two GLT1 blockers, dihydrokainic acid (500 μm) ordl-threo-β-benzyloxyaspartate (250 μm), or saline. Our results reveal that the ceftriaxone-mediated attenuation of cue-induced cocaine reinstatement is reversed by GLT1 blockade in core, but not shell, and further implicate core GLT1 as a potential therapeutic target for cocaine relapse.
Dysmyelination of Auditory Afferent Axons Increases the Jitter of Action Potential Timing during High-Frequency Firing
Authors: Kim Jun Hee , Renden Robert , von Gersdorff Henrique
Published: May 2013

Auditory neuropathies are linked to loss of temporal acuity of sound-evoked signals, which may be related to myelin loss. However, it is not known how myelin loss affects the waveform and temporal precision of action potentials (APs) in auditory CNS nerve terminals. Here we investigated the excitability of the calyx of Held nerve terminal in dysmyelinated auditory brainstems using the Long–Evans Shaker (LES) rat, a spontaneous mutant where compact myelin wrapping does not occur due to a genetic deletion of myelin basic protein. We found at relatively mature postnatal ages (15–17 d after birth)LESrat calyces showed prolonged spike latencies, indicative of a threefold reduction in the AP propagation velocity. Furthermore,LESrat afferent fiber-evoked APs showed a pronounced loss of temporal precision, even at low stimulation frequencies (10 Hz). While normal calyces were able to fire APs without failures at impressive rates of up to 1 kHz,LEScalyces were unable to do so. Direct recordings of the presynaptic calyx terminal AP waveform revealed that myelin loss does not affect the AP spike upstroke and downstroke kinetics, but dysmyelination reduces the after-depolarization and enhances the fast after-hyperpolarization peak following the AP spike in theLESrat. Together these findings show that proper myelination is essential not only for fast AP propagation, but also for precise presynaptic AP firing that minimizes both spike jitter and failures, two characteristics critically important for the accurate processing of sound signals in the auditory brainstem.
Lateral Hypothalamus Contains Two Types of Palatability-Related Taste Responses with Distinct Dynamics
Authors: Li Jennifer X. , Yoshida Takashi , Monk Kevin J. , Katz Donald B.
Published: May 2013

The taste of foods, in particular the palatability of these tastes, exerts a powerful influence on our feeding choices. Although the lateral hypothalamus (LH) has long been known to regulate feeding behavior, taste processing in LH remains relatively understudied. Here, we examined single-unit LH responses in rats subjected to a battery of taste stimuli that differed in both chemical composition and palatability. Like neurons in cortex and amygdala, LH neurons produced a brief epoch of nonspecific responses followed by a protracted period of taste-specific firing. Unlike in cortex, however, where palatability-related information only appears 500 ms after the onset of taste-specific firing, taste specificity in LH was dominated by palatability-related firing, consistent with LH's role as a feeding center. Upon closer inspection, taste-specific LH neurons fell reliably into one of two subtypes: the first type showed a reliable affinity for palatable tastes, low spontaneous firing rates, phasic responses, and relatively narrow tuning; the second type showed strongest modulation to aversive tastes, high spontaneous firing rates, protracted responses, and broader tuning. Although neurons producing both types of responses were found within the same regions of LH, cross-correlation analyses suggest that they may participate in distinct functional networks. Our data shed light on the implementation of palatability processing both within LH and throughout the taste circuit, and may ultimately have implications for LH's role in the formation and maintenance of taste preferences and aversions.
Distinct Inspiratory Rhythm and Pattern Generating Mechanisms in the preBötzinger Complex
Authors: Kam Kaiwen , Worrell Jason W. , Janczewski Wiktor A. , Cui Yan , Feldman Jack L.
Published: May 2013

In the mammalian respiratory central pattern generator, the preBötzinger complex (preBötC) produces rhythmic bursts that drive inspiratory motor output. Cellular mechanisms initiated by each burst are hypothesized to be necessary to determine the timing of the subsequent burst, playing a critical role in rhythmogenesis. To explore mechanisms relating inspiratory burst generation to rhythmogenesis, we compared preBötC and hypoglossal (XII) nerve motor activity in medullary slices from neonatal mice in conditions where periods between successive inspiratory XII bursts were highly variable and distributed multimodally. This pattern resulted from rhythmic preBötC neural population activity that consisted of bursts, concurrent with XII bursts, intermingled with significantly smaller “burstlets”. Burstlets occurred at regular intervals during significantly longer XII interburst intervals, at times when a XII burst was expected. When a preBötC burst occurred, its high amplitude inspiratory component (I-burst) was preceded by a preinspiratory component that closely resembled the rising phase of burstlets. Cadmium (8 μm) eliminated preBötC and XII bursts, but rhythmic preBötC burstlets persisted. Burstlets and preinspiratory activity were observed in ∼90% of preBötC neurons that were active during I-bursts. When preBötC excitability was raised significantly, burstlets could leak through to motor output in medullary slices andin vivoin adult anesthetized rats. Thus, rhythmic bursting, a fundamental mode of nervous system activity and an essential element of breathing, can be deconstructed into a rhythmogenic process producing low amplitude burstlets and preinspiratory activity that determine timing, and a pattern-generating process producing suprathreshold I-bursts essential for motor output.
Prefrontal Neurons of Opposite Spatial Preference Display Distinct Target Selection Dynamics
Authors: Lennert Therese , Martinez-Trujillo Julio C.
Published: May 2013

Neurons in the primate dorsolateral prefrontal cortex (dlPFC) of one hemisphere are selective for the location of attended targets in both visual hemifields. Whether dlPFC neurons with selectivity for opposite hemifields directly compete with each other for target selection or instead play distinct roles during the allocation of attention remains unclear. We explored this issue by recording neuronal responses in the right dlPFC of two macaques while they allocated attention to a target in one hemifield and ignored a distracter on the opposite side. Forty-nine percent of the recorded neurons were target location selective. Neurons selective for contralateral targets (58%) systematically discriminated targets from distracters faster than neurons selective for ipsilateral targets (42%). Additionally, during trials in which sensory stimulation remained the same but both stimuli were task irrelevant and animals were required to detect a change in the color of a fixation spot, contralateral neurons still reliably discriminated the putative target from the distracter, whereas ipsilateral neurons did not. The latter result indicates that target-distracter discrimination by contralateral neurons could occur independently of discrimination by ipsilateral cells; thus, the two cell types may represent two different components of the prefrontal circuitry underlying the allocation of attention to targets in the presence of distracters. Moreover, the response of both contralateral and ipsilateral neurons to a single target was substantially reduced by the presence of a distracter in the contralateral hemifield. This result suggests that the presence of the distracter triggered inhibitory interactions within the dlPFC circuitry that suppressed responses to the attended target.
The Ion Channel TRPA1 Is Required for Chronic Itch
Authors: Wilson Sarah R. , Nelson Aislyn M. , Batia Lyn , Morita Takeshi , Estandian Daniel , Owens David M. , Lumpkin Ellen A. , Bautista Diana M.
Published: May 2013

Chronic itch is a debilitating condition that affects one in 10 people. Little is known about the molecules that mediate chronic itch in primary sensory neurons and skin. We demonstrate that the ion channel TRPA1 is required for chronic itch. Using a mouse model of chronic itch, we show that scratching evoked by impaired skin barrier is abolished in TRPA1-deficient animals. This model recapitulates many of the pathophysiological hallmarks of chronic itch that are observed in prevalent human diseases such as atopic dermatitis and psoriasis, including robust scratching, extensive epidermal hyperplasia, and dramatic changes in gene expression in sensory neurons and skin. Remarkably, TRPA1 is required for both transduction of chronic itch signals to the CNS and for the dramatic skin changes triggered by dry-skin-evoked itch and scratching. These data suggest that TRPA1 regulates both itch transduction and pathophysiological changes in the skin that promote chronic itch.
Recombination-Induced Tag Exchange (RITE) Cassette Series to Monitor Protein Dynamics in Saccharomyces cerevisiae
Authors: Terweij Marit , van Welsem Tibor , van Deventer Sjoerd , Verzijlbergen Kitty F , Menendez-Benito Victoria , Ontoso David , San-Segundo Pedro , Neefjes Jacques , van Leeuwen Fred
Published: May 2013

Proteins are not static entities. They are highly mobile, and their steady-state levels are achieved by a balance between ongoing synthesis and degradation. The dynamic properties of a protein can have important consequences for its function. For example, when a protein is degraded and replaced by a newly synthesized one, posttranslational modifications are lost and need to be reincorporated in the new molecules. Protein stability and mobility are also relevant for the duplication of macromolecular structures or organelles, which involves coordination of protein inheritance with the synthesis and assembly of newly synthesized proteins. To measure protein dynamics, we recently developed a genetic pulse-chase assay called recombination-induced tag exchange (RITE). RITE has been successfully used in Saccharomyces cerevisiae to measure turnover and inheritance of histone proteins, to study changes in posttranslational modifications on aging proteins, and to visualize the spatiotemporal inheritance of protein complexes and organelles in dividing cells. Here we describe a series of successful RITE cassettes that are designed for biochemical analyses, genomics studies, as well as single cell fluorescence applications. Importantly, the genetic nature and the stability of the tag switch offer the unique possibility to combine RITE with high-throughput screening for protein dynamics mutants and mechanisms. The RITE cassettes are widely applicable, modular by design, and can therefore be easily adapted for use in other cell types or organisms.
Growth of Self Organized Eutectic Fibers from LiF─Rare Earth Fluoride Systems
Authors: Klimm Detlef , Acosta Maria F , dos Santos Ivanildo A , Ranieri Izilda M , Ganschow Steffen , Merino Rosa I
Published: May 2013

Eutectic fibers consisting of an ordered arrangement of LiF fibrils inside a LiREF4 matrix (RE = Y, Gd) can be grown with the micro-pulling-down method at sufficiently large pulling rate exceeding 120 mm/h. The distance between individual fibrils could be scaled down to 1 µm at 300 mm/h pulling. LiF-LiYF4 has stronger tendency to form facetted eutectic colonies than LiF-LiGdF4, explained by the larger entropy of melting of the former.
Emprego da azida sódica, como conservador de fezes, para a pesquisa de ovos de Schistosoma mansoni pelo método de Kato-Katz
Authors: Gonçalves Elenice Messias do Nascimento , Campos Rubens , Amato Neto Vicente , Pinto Pedro Luiz Silva , Moreira Antônio Augusto Baillot
Published: May 2013

O método de Kato-Katz é muito utilizado para pesquisa de ovos de helmintos nasfezes e, em determinadas ocasiões, como por exemplo no trabalho de campo, afigura-se conveniente preservar o material a examinar, com o intuito de facilitar o transporte e operacionalidade. Na tentativa de poder usar conservador sôliào, capaz de, em relação a ovos de Schistosoma mansoni, manter a morfologia, impedir a evolução e não interferir no processo de clarificação pela glicerina, os autores utilizaram a azida sádica (NaN3), que foi misturada, na quantidade de 2-3mg em aproximadamente 2 g de fezes de pacientes eliminando número conhecido de ovos, quantificados pelo processo de Kato-Katz. As fezes com preservador ficaram mantidas em temperatura ambiente e foram feitas contagens, pela mesma técnica, após uma, duas, quatro, oito e doze semanas. As observações, feitas em 53 amostras, demonstraram que em 51 o número de ovos permaneceu, aproximadamente, idêntico e com estruturas conservadas, de molde a permitir o dignóstico. Em dois casos, nas oitava e décima-segunda semanas, as fezes estavam desidratadas, ressecadas e impróprias para a contagem. A azida sódica, portanto, mostrou-se adequada para a conservação de fezes a serem submetidas ao método de Kato-Katz.
Malaria in humait a county, state of Amazonas, Brazil. XIX - evaluation of clindamycin for the treatment of patients with Plasmodium falciparum infection
Authors: Meira Domingos Alves , Pereira Paulo Camara Marques , Marcondes-Machado Jussara , Mendes Rinaido Poncio , Barraviera Benedito , Pirola José Antonio G. , Guimarães Maria Regina Cotrim , Curi Paulo Roberto , Rodrigues Renato Pedro
Published: May 2013

A total of 207 patients with malaria caused by Plasmodium falciparum were submitted to 5 different treatment schedules with clindamycin from 1981 to 1984: A - 89 patients were treated intravenously and orally, or intramuscularly and orally with 20 mg/kg/day divided into two daily applications for 5 to 7 days; B-40 patients were treated orally with 20 mg/kg/day divided into two daily doses for 5 to 7 days; C-27 patients were treated with 20 mg/kg/day intravenously or orally divided into two daily applications for 3 days; D-16 patients were treated orally and/or intravenously with a single daily dose of 20 to 40 mg/kg/day for 5 to 7 days; E-35 patients were treated orally with 5 mg/kg/day divided into two doses for 5 days. Patients were examined daily during treatment and reexamined on the 7th, 24th, 21st, 28th and 35th day both clinically and parasitologically (blood test). Eighty three (40.1%) had moderate or severe malaria, and 97 (46.8%) had shown resistance to chloroquine or to the combination ofsulfadoxin and pyrimethamine. The proportion of cured patients was higher than 95% among patients submitted to schedules A and B. Side effects were only occasional and of low intensity. Three deaths occurred (1.4%), two of them involving patients whose signs and symptoms were already very severe when treatment was started. Thus, clindamycin proved to be very useful in the treatment of patients with malaria caused by Plasmodium falciparum and we recommend schedule A for moderate and severe cases and Bfor initial cases.
Trypanosoma (herpetosoma) Rangeli tejera, 1920: influence of host weight, size of inoculum, and route of infection upon experimental parasitemia
Authors: Tejero Felix , Galli Natiela , Urdaneta-Morales Servio
Published: May 2013

To study the influence of host age, inoculum size, and route of infection on Trypanosoma (Herpetosoma) rangeli, 12 lots of 6.0 g albino mice (NMRI strain) were infected up. with from 25x10¹ to 25x10(6) trypomastigotes/gram body weight harvested from LIT medium. The lower inocula produced low but persistent parasitemias, while the higher inocula produced high levels of parasitemia that fell quickly, suggesting the mobilization of resistance mechanisms. In other experiments, i.p. inoculation produced higher parasitemias than s.c. inoculation, and 6.0 g mice had higher parasitemias than 16.0 or 26.0 g mice. Thus, a standard methodology would seem to be necessary in the study of the various strains and/or species that may make up the T. rangeli complex.
Transmissão do Trypanosoma cruzi em um caso, durante aleitamento, em área nâo endêmica
Authors: Medina-Lopes Maria das Dores
Published: May 2013

É relatado um caso de fase aguda inaparente da doença de Chagas em lactente de sete meses de idade, filho de chagàsica crônica. Excluiu-se a possibilidade de transmissão congênita, vetorial ou por hemotransfusão concluindo-se pela transmissão da infecção chagàsica via aleitamento materno.
Acometimento da supra-renal associado à paracoccidioidomicose
Authors: Diniz Leonardo Maurício , Pedroso Ênio Roberto Pietra , Bambirra Eduardo
Published: May 2013

A supra-renal foi estudada em 60pacientes com paracoccidioidomicose. Dentre eles, 10(16,7%) apresentavam alterações anatômicas ou funcionais das supra-renais. As lesões glandulares associaram-se à paracoccidioidomicose disseminada, com evolução da doença de pelo menos cinco anos sem tratamento e com hipotensão arterial sistêmica. Não houve associação entre alterações anatomoclínicas supra-renais e alterações raáiolôgicaspulmonares. Esses dados revelam a importância da avaliação sistemática da função supra-renal em portadores de formas disseminadas da paracoccidioidomicose.
Alternativas de controle do Triatoma sórdida no Triângulo Mineiro. I. Borrifação parcial (intradomicílio) no Município de Douradoquara, MG, Brasil
Authors: Diotaiuti Liléia , Carneiro Mariângela , Loiola Carlos Catão P. , Silveira Neto Horácio V. , Coutinho Rosana Mourão , Dias João Carlos Pinto
Published: May 2013

O município de Douradoquara vem sendo regularmente trabalhado pela SUCAM desde 1975. Atualmente, a espécie prevalente é o T. sórdida, cujo comportamento peridomiciliarfoi aqui estudado na ausência de qualquer inseticida, tomando-se o cuidade de proteger a população através da borrifação dos intradomicílios das unidades positivas em pesquisa integral realizada no primeiro semestre/1985. Um ano depois, realizou-se nova pesquisa, confirmando-se a presença abundante do T. sórdida noperidomicílio. Observamos aumento significativo do número de unidades domiciliares positivas em relação à primeira, acompanhada por aumento no número de exemplares de triatomíneos capturados. O principal ecótopo encontrado foi o paiol seguido pelo galinheiro, chiqueiro e outros. A negativação espontânea de alguns ecótopos e a positivação de outros indicam grande mobilidade desta espécie, inclusive das ninfas. Conclui-se pela necessidade de: borrifação do intradomicilio da unidade domiciliar positiva; borrifação do peridomicílio infestado para controle do tamanho das colônias, dificultando o processo de domiciliação triatominica; desenvolvimento de formas alternativas de controle, especialmente em que se busque participação comunitaria.
A retrospective study of 40 victims of Crotalus snake bites: analysis of the hepatic necrosis observed in one patient
Authors: Barraviera Benedito , Bonjorno Junior José Carlos , Arakaki Denise , Domingues Maria Aparecida C. , Pereira Paulo Camara Marques , Mendes Rinaldo P. , Machado Jussara Marcondes , Meira Domingos Alves
Published: May 2013

Forty patients with a diagnosis of snake bite were studied at the Infectious and Parasitic Disease Service of the Faculty of Medicine of Botucatu. Thirty were males and 10 females, ranging in age from 16 to 70 years. All were farm laborers and 35 of them were bitten in the lower limbs. Two of the 9 patients seen more than 6 hours after the bite died. The low mortality rate (5%) observed could be explained by the early care provided, by the use of appropriate doses of anti-crotalus serum, parenteral hydration, urine alkalinization with sodium bicarbonate and induction of osmotic diuresis with a mannitol solution. Anatomopathological examination of one of the patients who died revealed extensive hepatic necrosis. The authors discuss the possibility of the effect of a factor of snake venom in the genesis of hepatic necrosis and in the increased transaminase levels.
Hemodinâmica glomerular renal no roedor Calomys callosus
Authors: Boim Mirian A. , Schor Nestor
Published: May 2013

A função renal do roedor Calomys callosus, envolvido no ciclo de transmissão de diversos agentes patogênicos para o homem foi avaliada no animal intacto, através da técnica de depuração e micropunção renal. Os resultados mostraram que este roedor apresenta níveis pressóricos, hematócrito e proteinas plasmáticas semelhantes aos dos ratos submetidos ao mesmo procedimento experimental. Os pesos corporal e renal, bem como a filtração glomerular global e por nefro assemelham-se aos do camundongo. Surpreendentemente estes roedores apresentaram significante número de glomérulos superficiais por rim, permitindo a avaliação da hemodinàmica glomerular. Apesar da pressão arterial semelhante à dos ratos Munich-Wistar (MW), a pressão hidráulica intraglomerular no Calomys callosus foi inferior. Esta redução foi conseqüente à menor resistência pós-glomerular quando comparada à dos ratos MW. O fluxo plasmático glomerular atingiu valor bastante elevado em relação à filtração glomerular por nefro, fato que não só compensaria a reduzida pressão intraglomerular, como também seria suficiente para elevar a filtração (por g/rim) a níveis superiores neste roedor, pois o coeficiente de ultrafiltração glomerular (Kj) foi semelhante ao do rato MW. O presente trabalho sugere que apesar das dificuldades técnicas que este animal impõe devido ao seu reduzido tamanho, o estudo da função renal global bem como da hemodinàmica glomerular é factível, podendo portanto ser utilizado como modelo para estudo da função renal em doenças tropicais.