bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effects of fear conditioning on cerebellar LTP and LTD
Authors: Zhu Lan , Scelfo Bibiana , Hartell Nicholas A. , Strata Piergiorgio , Sacchetti Benedetto 
Published: June 2007

AbstractLong‐term potentiation (LTP) and depression (LTD) at parallel fibre–Purkinje cell synapses have been described in vitro in the cerebellar cortex, but the physiological roles of these two forms of plasticity have not been well defined. Here we show that, in cerebellar slices taken from rats that had undergone fear conditioning, there was a significant occlusion of electrically induced LTP at parallel fibre–Purkinje cell synapses. This effect was long‐lasting and related to associative processes, as LTP was not occluded in unpaired animals. Notably, in conditioned animals the LTP‐inducing protocol produced LTD in some cells instead of LTP. Conversely, synaptic depression induced by conjunctive stimulation of parallel fibers and climbing fibres was impaired in tissue taken immediately following aversive stimulation in both paired and unpaired subjects. This effect was not, however, long‐lasting as the incidence and extent of LTD returned to normal levels 24 h after behavioural testing. These findings suggest that LTP takes part in the mechanisms underlying aversive associative memories in the cerebellum.
Deep propofol sedation for vacuum‐assisted bite‐block immobilization in children undergoing proton radiation therapy of cranial tumors
Authors: WEISS MARKUS , FREI MARTINA , BUEHRER SABIN , FEURER RITA , GOITEIN GUDRUN , TIMMERMANN BEATE 
Published: June 2007

SummaryBackground:  Vacuum‐assisted bite‐block immobilization of the head is a reliable technique for reproducible precise head positioning as used for proton radiation in adults. We report preliminary experience using deep propofol sedation without an artificial airway in children undergoing proton radiation of cranial tumors requiring vacuum‐assisted bite‐block immobilization.Methods:  Sedation was started with a bolus of i.v. midazolam followed by repeated small boluses of propofol as required to tolerate bite‐block insertion and patient positioning. Sedation was maintained by continuous propofol infusion until removal of the bite block. Oxygen was administered by a nasal cannula. SpO2, endtidal CO2 taken at the nose and respiratory adverse events such as coughing, bucking, airway obstruction, regurgitation or aspiration were recorded. Data are mean ± sd.Results:  Ten children aged 2.6 ± 0.8 years were treated to date. For each child, cumulative 26.7 ± 1.9 radiation fractions were administered. Propofol dose administered for induction, bite‐block insertion and patient positioning was 3.9 ± 0.5 mg·kg−1. Time from insertion to removal of the bite block lasted 48.3 ± 6.2 min. Endtidal CO2 values were 5.6 ± 0.8 kPa (43 ± 7 mmHg) and SpO2 values were 98.3 ± 1.9% with spontaneous breathing, supplemental oxygen and bite block inserted. No respiratory adverse events occurred during the 267 sedation procedures performed.Conclusion:  Deep propofol sedation without the use of an artificial airway is an interesting technique for vacuum‐assisted bite‐block immobilization in young children undergoing precise radiation therapy of cranial tumors. However, simultaneous individual anesthetic challenges require pediatric anesthesiologists highly experienced with the pediatric airway, clinical alertness and closed monitoring.
Anaphylactic shock in a beta‐blocked child: usefulness of isoproterenol
Authors: MOMENI MONA , BRUI BARBARA , BAELE PHILIPPE , MATTA AMINE 
Published: June 2007

SummaryLike adults, children taking beta‐blockers are at risk for serious hemodynamic instability in case of anaphylaxis. We report a case of severe bradycardia associated with anaphylactic shock after aprotinin in a beta‐blocked child, which was resistant to intravenous epinephrine and vascular filling but was treated successfully with isoproterenol.
Awareness during pediatric anesthesia – what is the position of European pediatric anesthesiologists?
Authors: ENGELHARDT THOMAS , PETROZ GUY C. , MCCHEYNE ALAN , BISSONNETTE BRUNO 
Published: June 2007

SummaryBackground:  The incidence of awareness in the pediatric population is reported as high as 1 : 125. An online survey was conducted about the current perception and practice of members of the British and French pediatric anesthesia societies regarding awareness during general anesthesia.Methods:  Following the approval of the executive committees of the British and French pediatric anesthesia societies, members with a valid email contact address were invited to participate in a web‐based survey. Perceived risk factors, use of awareness monitors, pre‐ and postoperative discussions of awareness as well as personal experience were enquired.Results:  A total of 302 (51%) responded to the email survey. More than 60% indicated that awareness is a problem in pediatric anesthesia with the majority estimating an incidence of 1 : 1000. Almost half (49%) the respondents believe that awareness is age‐dependent and 50% are not concerned below 1 month of age. More than 86% of respondents do not discuss the risk of awareness with the parents or actively look for awareness despite 27% reporting at least one episode in their practice. Intra‐operative monitoring almost exclusively consists of clinical signs and endtidal anesthetic concentrations. Bispectral index (BIS) monitoring is routinely used by approximately 10% of the surveyed members.Conclusions:  This survey demonstrates that European pediatric anesthesiologists perceive awareness as a major problem. However, none seems to address the issue openly or looks for its presence routinely. The vast majority of pediatric anesthesiologists rely almost exclusively on clinical monitoring and endtidal anesthetic concentrations for its detection.
Combined spinal – epidural anesthesia in major abdominal surgery in high‐risk neonates and infants
Authors: SOMRI MOSTAFA , TOME RIAD , YANOVSKI BORIS , ASFANDIAROV ELDAR , CARMI NURIT , MOGILNER JOERGE , DAVID BADER , GAITINI LUIS A. 
Published: June 2007

SummaryBackground:  Combined spinal‐epidural anesthesia (CSE‐A) is reportedly safe and effective for the pediatric population in infraumbilical surgery. Our main purpose was to describe our experience of this technique in neonates and infants undergoing elective major upper abdominal surgery.Methods:  Spinal anesthesia was performed in 28 neonates and infants with isobaric bupivacaine 0.5%, 1 mg·kg−1 followed by placement of a caudal epidural catheter to thoracic spinal segments. The catheter tip position was confirmed radiographically. Respiratory and hemodynamic data were collected before and after the CSE‐A and throughout the operation, as a measure of anesthetic effectiveness. Complications related to the anesthesia technique were collected as a measure of the anesthetic technique safety.Results:  Satisfactory surgical anesthesia was achieved in 24 neonates and infants, four patients were converted to general anesthesia. Respiratory and hemodynamic variables did not change significantly during surgery, compared with baseline values: oxygen saturation (P = 0.07), systolic and diastolic blood pressures (P = 0.143, P = 0.198 respectively), heart rate (P = 0.080) and respiratory rate (P = 0.127). However, twenty infants were fussy during the surgical procedures and were calmed with intravenous midazolam; our patients required oxygen supplementation and transient manual ventilation intraoperatively.Conclusions:  Combined spinal‐epidural anesthesia could be considered as an effective anesthetic technique for elective major upper abdominal surgery in awake or sedated neonates and infants, and could be used cautiously by a pediatric anesthesiologist as an alternate to general anesthesia in high‐risk neonates and infants undergoing upper gastrointestinal surgery.
Clinical and diagnostic imaging findings predict anesthetic complications in children presenting with malignant mediastinal masses
Authors: ANGHELESCU DORALINA L. , BURGOYNE LAURA L. , LIU TIEBIN , LI CHIN‐SHANG , PUI CHING‐HON , HUDSON MELISSA M. , FURMAN WAYNE L. , SANDLUND JOHN T. 
Published: June 2007

SummaryBackground:  The presence of a mediastinal mass in a child poses significant anesthesia‐related risks including death. To optimize outcome clinicians must be able to predict which patients are at highest risk of anesthetic complications.Methods:  We conducted a retrospective review of 118 pediatric patients who presented with mediastinal masses. We investigated their medical records for clinical symptoms and signs at presentation and reviewed their chest radiographs, computed tomography scans, and echocardiograms and electrocardiograms when available. We then conducted analyses to identify clinical and diagnostic imaging features associated with anesthesia‐related complications.Results:  Eleven of 117 [9.4%, 95% confidence interval (CI) 4.1–14.7%] patients experienced an anesthesia‐related complication. Four preoperative features were significantly associated with anesthetic complications: orthopnea (P = 0.033, odds ratio (OR) 5.31, 95% CI, 1.15–24.56), upper body edema (P = 0.035, OR 8.00, 95% CI, 1.16–55.07), great vessel compression (P = 0.037, OR 5.41, 95% CI, 1.11–26.49), and main‐stem bronchus compression (P = 0.044, OR 5.11, 95% CI, 1.05–24.92). The presence of pleural effusion (P = 0.060, OR 4.53, 95% CI, 0.94–21.96) or tracheal compression (P = 0.061, OR 5.09, 95% CI, 0.93–27.81) also appeared to be risk factors. Although the rate of anesthesia‐related complications detected in our cohort was comparable with that found in earlier studies, the events were less severe.Conclusions:  Patients who present with orthopnea, upper body edema, great vessel compression and main stem bronchus compression are at risk of anesthesia‐related complications. The low severity of complications in our series may reflect a combination of factors: use of the least invasive method such as interventional radiology to obtain tissue for diagnosis, completion of a thorough preoperative assessment and minimal anesthesia intervention.
Conifer phenolic resistance markers are bark beetle antifeedant semiochemicals
Authors: Faccoli Massimo , Schlyter Fredrik 
Published: June 2007

Abstract1 Phenols are important in conifer resistance to fungi associated with bark beetles and as markers for resistance to beetle mass‐attacks. However, the mechanism of phenolic activity in conifer resistance to Ips typographus bark beetle remains unclear.2 By a new bioassay, we tested the effect on host acceptance and tunnelling of male and female I. typographus in an artificial gallery (13 mm long) for 4 h (no‐choice test). To the artificial diet, an aliquot of host (catechin, taxifolin, or resveratrol) or nonhost (E‐conophthorin) compounds was added, singly tested at doses close to those of tree bark. Host acceptance and tunnelling was measured by the amount of diet removed by the insects.3 All tested chemicals decreased the tunnelling activity of I. typographus, with an antifeedant effect stronger in males and increasing with dose. No mortality was recorded. The nonhost volatile spiroketal, E‐conophthorin, had the highest antifeedant activity both in males and females. Among host compounds, effects and dose–response were weak in females. Both catechin and E‐conophthorin gave a 50% reduction of tunnelling at a concentration of 0.1% for males, the pioneering (host selecting) sex in Ips. The threshold of activity for host compounds to males was at concentrations of 0.03–0.1%, which corresponds to, or is less than, the concentrations reported from spruce host bark.4 The results allow us to support the hypothesis of a direct behavioural antifeedant mechanism for resistance from those phenols that are particularly active for the pioneering males during tree attack.
Global survey of diversity among environmental saltwater Bacteriovoracaceae
Authors: Pineiro Silvia A. , Stine O. Colin , Chauhan Ashvini , Steyert Susan R. , Smith Richard , Williams Henry N. 
Published: June 2007

SummaryHalophilic Bacteriovorax (Bx), formerly known as the marine Bdellovibrio, are Gram‐negative, predatory bacteria found in saltwater systems. To assess their genetic diversity and geographical occurrence, the small subunit rRNA (ssu‐rRNA) gene sequences were analysed from 111 marine, salt lake and estuarine isolates recovered from 27 locations around the world. Phylogenetic analysis of these isolates using Geobacter as the outgroup revealed eight distinct ribotype clusters each with at least two isolates. Each cluster was composed of isolates with ≥ 96.5% similarity in ssu‐rRNA sequences. Three single isolate outliers were observed. Many of the Bx ribotypes were widely dispersed among different types of ecosystems (e.g. cluster III was recovered from the Great Salt Lake, the Atlantic Ocean, Pacific Ocean, Chesapeake Bay and gills of aquarium fish). However, cluster V was only recovered from a single ecosystem, estuaries. Cluster V was originally detected in the Chesapeake Bay and subsequently in the Pamlico Sound/Neuse River system. Principal coordinate analysis revealed that the sequences of the isolates from different environments were distinct from each other. The results of this study reveal the saltwater Bx to be phylogenetically and environmentally more diverse than was previously known.
Sperm ultrastructure of five species of the Neotropical ant genusPseudomyrmex(Hymenoptera: Formicidae)
Authors: Moya J. , Mancini K. , Lino‐Neto J. , Delabie J. , Dolder H. 
Published: June 2007

AbstractThe seminal vesicles of adult males of five species ofPseudomyrmexwere prepared for light and transmission electron microscopy. ThePseudomyrmexspermatozoa are long and slender with similar morphology. The head region has an acrosome and a nucleus. In all the studied species, two morphologically distinct types of acrosomal vesicles were observed, a long structure, as observed in all known ants, and a pear‐shaped one, never before observed in ants. The nucleus is elongated and both condensed and loose chromatin are present. The flagellum has an axoneme, a centriolar adjunct, two mitochondrial derivatives and two accessory bodies. The centriolar, the mitochondrial derivatives and the accessory bodies are similar to observations in most ant species that have been studied. The axoneme presents an uncommon 9 + 9 + 1 microtubule arrangement and the central microtubule has 13 protofilaments. The acrosomal dimorphism and the different levels of chromatin organization are exclusive characteristics ofPseudomyrmex. Furthermore, the 9 + 9 + 1 microtubule arrangement is different from all Hymenoptera, as well as from most insects, which present a 9 + 9 + 2 arrangement. These new morphological characters that are specific toPseudomyrmex, are valuable synapomorphies of the genus and can be used in taxonomic characterization of the Pseudomyrmecinae subfamily and in phylogenetic analyses in Formicidae family.
Ultrastructural, histochemical and cytochemical characterization of intestinal epithelial cells in Aplysia depilans (Gastropoda, Opisthobranchia)
Authors: Lobo‐da‐Cunha Alexandre , Batista‐Pinto Carla 
Published: June 2007

AbstractTo improve the current knowledge about the digestive system in opisthobranchs, light and electron microscopy methods were used to characterize the epithelial cells in the mid‐intestine of Aplysia depilans. This epithelium is mainly formed by columnar cells intermingled with two types of secretory cells, named mucous cells and granular cells. Columnar cells bear microvilli on their apical surface and most of them are ciliated. Mitochondria, multivesicular bodies, lysosomes and lipid droplets are the main components of the cytoplasm in the region above the nucleus of these cells. Peroxisomes are mainly found in middle and basal regions, usually close to mitochondria. Mucous cells are filled with large secretory vesicles containing thin electron‐dense filaments surrounded by electron‐lucent material in which acidic mucopolysaccharides were detected. The basal region includes the nucleus, several Golgi stacks and many dilated rough endoplasmic reticulum cisternae containing tubular structures. The granular cells are characterized by very high amounts of flat rough endoplasmic reticulum cisternae and electron‐dense spherical secretory granules containing glycoproteins. Enteroendocrine cells containing small electron‐dense granules are occasionally present in the basal region of the epithelium. Intraepithelial nerve fibres are abundant and seem to establish contacts with secretory and enteroendocrine cells.
Morphology of the male reproductive system and spermatophore formation in the freshwater ‘red claw’ crayfish Cherax quadricarinatus (Von Martens, 1898) (Decapoda, Parastacidae)
Authors: López Greco Laura S. , Vazquez Fernanda , Rodríguez Enrique M. 
Published: June 2007

AbstractThe morphology of the male reproductive system was studied in Cherax quadricarinatus. The testes and vasa deferentia were dissected, fixed, cut and stained. Testes appear as two parallel and opalescent strands; they present many testicular lobes, each lobe containing cells in the same stage of the spermatogenic cycle. A vas deferens arises from the external side of each testis and three parts were clearly distinguished: proximal vas deferens (PVD), middle vas deferens (MVD) and distal vas deferens (DVD). The PVD is opalescent and highly convoluted, the MVD is pale white in colour and convoluted, but wider in diameter than the PVD, while the DVD shows the widest diameter, is straight and is white in colour. A single‐layered epithelium is recognized in the vas deferens; with cylindrical cells in the PVD and cuboid cells in the MVD and DVD. The formation of the spermatophore starts at the PVD, while the secondary layer of the spermatophore seems to be added at the MVD. At the DVD, the highly coiled spermatophore is surrounded by the periodic acid Schiff‐positive sticky components of the secondary layer. Many aspects of spermatophore formation in C. quadricarinatus differ from those of other Astacida. The applied aspects of this study for aquaculture purposes are discussed.
Early development of the aplacophoran mollusc Chaetoderma
Authors: Nielsen Claus , Haszprunar Gerhard , Ruthensteiner Bernhard , Wanninger Andreas 
Published: June 2007

AbstractThe early development of the trochophore larva of the aplacophoran Chaetoderma nitidulum (Mollusca: Caudofoveata = Chaetodermomorpha) is described using scanning and transmission electron microscopy and using fluorescence staining and confocal laser scanning microscopy of the muscle system. The most important features include the presence of a prototroch and a telotroch, serially arranged glandular cells (spiculoblasts) at the dorsal mantle, the occurrence of a ventral suture as a possible remnant of a former foot sole, and the presence of a pair of protonephridia. The development of the early anlagen of the circular body wall muscles does not show the anterior–posterior mode of formation that is typical for annelids, thus strengthening the hypothesis of a non‐segmented ancestry of Mollusca.
Interspecific variation of sperm morphology in the Australian rodent genus Zyzomys
Authors: Breed William G. , Leigh Chris M. , Robertson Helen , Mantellato Lisa , Lambert Cathy , Jequier Anne , Matson Phillip 
Published: June 2007

AbstractThe sperm head morphology and tail length of two species of Australian rock rats, Zyzomys argurus and Zyzomys pedunculatus, are presented. In Z. argurus the sperm head has an apical hook together with two ventral processes extending from the upper concave surface that are largely composed of cytoskeletal material, and the sperm tail is about 135 µm in length. By contrast, in Z. pedunculatus the sperm head is paddle‐shaped with the nucleus capped by an acrosome that has a large apical segment and is surrounded by a thin layer of cytoskeletal material, and the sperm tail is only around 85 µm in length. Since the structure of the spermatozoon of Z. argurus is similar to that of most of the old endemic Australian rodents it is presumed to be the ancestral condition within the Zyzomys genus with that of Z. pedunculatus being highly derived and showing convergence with the sperm structure in some other orders of mammals.
Spatial autocorrelation and the selection of simultaneous autoregressive models
Authors: Kissling W. Daniel , Carl Gudrun 
Published: June 2007

ABSTRACTAim Spatial autocorrelation is a frequent phenomenon in ecological data and can affect estimates of model coefficients and inference from statistical models. Here, we test the performance of three different simultaneous autoregressive (SAR) model types (spatial error = SARerr, lagged = SARlagand mixed = SARmix) and common ordinary least squares (OLS) regression when accounting for spatial autocorrelation in species distribution data using four artificial data sets with known (but different) spatial autocorrelation structures.Methods We evaluate the performance of SAR models by examining spatial patterns in model residuals (with correlograms and residual maps), by comparing model parameter estimates with true values, and by assessing their type I error control with calibration curves. We calculate a total of 3240 SAR models and illustrate how the best models [in terms of minimum residual spatial autocorrelation (minRSA), maximum model fit (R2), or Akaike information criterion (AIC)] can be identified using model selection procedures.Results Our study shows that the performance of SAR models depends on model specification (i.e. model type, neighbourhood distance, coding styles of spatial weights matrices) and on the kind of spatial autocorrelation present. SAR model parameter estimates might not be more precise than those from OLS regressions in all cases. SARerrmodels were the most reliable SAR models and performed well in all cases (independent of the kind of spatial autocorrelation induced and whether models were selected by minRSA,R2or AIC), whereas OLS, SARlagand SARmixmodels showed weak type I error control and/or unpredictable biases in parameter estimates.Main conclusions SARerrmodels are recommended for use when dealing with spatially autocorrelated species distribution data. SARlagand SARmixmight not always give better estimates of model coefficients than OLS, and can thus generate bias. Other spatial modelling techniques should be assessed comprehensively to test their predictive performance and accuracy for biogeographical and macroecological research.
Ecological correlates of geographical range occupancy in North American birds
Authors: Hurlbert Allen H. , White Ethan P. 
Published: June 2007

ABSTRACTAim The degree to which a species is predictably encountered within its range varies tremendously across species. Understanding why some species occur less frequently within their range than others has important consequences for conservation and for analyses of ecological patterns based on range maps. We examined whether patterns in geographical range occupancy can be explained by species‐level traits.Location North America.Methods We used survey data from 1993 to 2002 from the North American Breeding Bird Survey along with digital range maps produced by NatureServe to calculate range occupancy for 298 species of terrestrial birds. We tested whether species traits explained variation in range occupancy values using linear regression techniques.Results We found three species traits that together explained more than half of the variation in range occupancy. Population density and niche breadth were positively correlated with occupancy, while niche position was negatively correlated with occupancy.Main conclusions Our results suggest that high range occupancy will occur in species that are common at sites on which they occur, that tolerate a relatively wide range of ecological conditions and that tend to have ranges centred on areas with common environmental conditions. Furthermore, it appears that niche‐based characteristics may explain patterns of distribution and abundance from local habitats up to the scale of geographical ranges.