bluuebunny/crossref_metadata_2025 huggingface dataset:
Dancing between the devil and deep blue sea: the stabilizing effect of enemy‐free and victimless sinks
Authors: Schreiber Sebastian J. , Lipcius Romuald N. , Seitz Rochelle D. , Chris Long W.
Published: February 2006

Theoretical and empirical studies have shown that enemy–victim interactions in spatially homogenous environments can exhibit diverging oscillations which result in the extinction of one or both species. For enemy–victim models with overlapping generations, we investigate the dynamical implications of spatial heterogeneity created by enemy‐free sinks or victimless sinks. An enemy‐free sink is a behavioral, physiological or ecological state that reduces or eliminates the victim's vulnerability to the enemy but cannot sustain the victim population. For victims that move in an ideal‐free manner, we prove that the inclusion of an enemy‐free sink shifts the population dynamics from diverging oscillations to stable oscillations. During these stable oscillations, the victim disperses in an oscillatory manner between the enemy‐free sink and the enemy‐occupied patch. Enemy‐free sinks with lower mortality rates exhibit oscillations with smaller amplitudes and longer periods. A victimless sink, on the other hand, is a behavioral, physiological or ecological state in which the enemy has limited (or no) access to its victims. For enemies that move in an ideal‐free manner, we prove that victimless sinks also stabilize diverging oscillations. Simulations suggest that suboptimal behavior due to information gathering or learning limitations amplify oscillations for systems with enemy‐free sinks and dampen oscillations for systems with victimless sinks. These results illustrate that the coupling of a sink created by unstable enemy–victim interactions and a sink created by unsuitable environmental conditions can result in population persistence at the landscape level.
Non‐additivity among multiple cues of predation risk: a behaviorally‐driven trophic cascade between owls and songbirds
Authors: A. Schmidt Kenneth
Published: February 2006

Non‐lethal effects of predators on prey are initiated in the form of responses to direct and indirect cues of predation risk. Like their lethal equivalents, non‐lethal effects may affect species further down the food web initiating a behaviorally‐driven trophic cascade. I presented a direct cue of predation risk, owl vocalizations, to white‐footed mice (Peromyscus leucopus) during either a new or full moon (indirect cue). Mice reduced their activity in space by nearly two‐thirds in response to playbacks of owl vocalizations during a full moon. However, neither moonlight (full vs new) nor the presence/absence of owl calls had an effect on space use when each cue varied singly. Previous studies have demonstrated a tight correlation between spatial activity in mice as used in the current experiment and nest predation rates on ground‐nesting birds. Because moonlight is a ubiquitous deterrent of activity in nocturnal rodents I used of long‐term nesting records the veery (Catharus fuscescens) to test whether nest predation rates were correlated negatively with moonlight. For half the lunar cycle (∼full moon to new moon) predation rates decreased with moonlight as predicted. During the second half of the lunar cycle predation and moonlight did not correlate as expected, but this was likely due to the depletion of vulnerable nests after a period of in which predation rates were at their maximum near the full moon. These studies suggest that the non‐lethal effects of predatory risk on mice (i.e. changes in space use) cascade to affect their prey. Through the mechanism of reduced space use by rodents, perceived predation risk has the potential to significantly and indirectly affect songbird nest predation rates.
Estimation of local extinction rates when species detectability covaries with extinction probability: is it a problem?
Authors: Jenouvrier Stephanie , Boulinier Thierry
Published: February 2006

Estimating the rate of change of the composition of communities is of direct interest to address many fundamental and applied questions in ecology. One methodological problem is that it is hard to detect all the species present in a community. Nichols et al. presented an estimator of the local extinction rate that takes into account species probability of detection, but little information is available on its performance. However, they predicted that if a covariance between species detection probability and local extinction rate exists in a community, the estimator of local extinction rate complement would be positively biased.

Here, we show, using simulations over a wide range of parameters that the estimator performs reasonably well. The bias induced by biological factors appears relatively weak. The most important factor enhancing the performance (bias and precision) of the local extinction rate complement estimator is sampling effort. Interestingly, a potentially important biological bias, such as the covariance effect, improves the estimation for small sampling efforts, without inducing a supplementary overestimation when these sampling efforts are high. In the field, all species are rarely detectable so we recommend the use of such estimators that take into account heterogeneity in species detection probability when estimating vital rates responsible for community changes.
Cost of chemical defence in the red alga Delisea pulchra
Authors: A. Dworjanyn Symon , T. Wright Jeffrey , A. Paul Nicholas , De Nys Rocky , D. Steinberg Peter
Published: February 2006

The concept of a cost of defence is fundamental to theories for the evolution of defences against consumers. However, the evidence for a cost of plant chemical defences is mixed, and often indirect. This is particularly true for marine macroalgae (seaweeds), for which inferences of cost to date rely almost exclusively on phenotypic correlations between one class of secondary metabolites (brown algal phlorotannins) and growth (or, in one instance, fecundity). No studies of the cost of seaweed chemical defense have experimentally manipulated the presence of secondary metabolites in a controlled fashion and only one previous study has considered genetic background as a factor. Here we measured the cost of halogenated furanones to the red seaweed Delisea pulchra in three ways: a) phenotypic correlations between concentrations of furanones and fecundity in field collected thalli; b) genetic correlations between concentrations of furanones and growth for clones of thalli grown from tetraspores, and c) by comparing growth rates of thalli for which furanone production was experimentally inhibited (furanone ‐) vs thalli which produced furanones (furanone +). Two of our three tests‐correlations between furanones and fecundity, and the growth of furanone (+) vs furanone (−) thalli‐indicated a cost of furanones to D. pulchra but genetic correlations between furanones and growth did not. We suggest that these apparently conflicting results are consistent with the consequences of apical growth in this alga, and may further result from a cost of furanones only being manifested at critical developmental stages or times of tissue differentiation.
Review article: the role of pH monitoring in extraoesophageal gastro‐oesophageal reflux disease
Authors: VAEZI M. F.
Published: February 2006

Gastro‐oesophageal reflux disease is associated with several extraoesophageal disease states including laryngitis, asthma, chronic cough and non‐cardiac chest pain. Currently, the exact role reflux of gastric contents play in the pathogenesis of extraoesophageal symptoms remain controversial.

Twenty‐four hours pH monitoring is often considered the ‘gold standard’ in the diagnosis of gastro‐oesophageal reflux disease and is increasingly utilized in patients with extraoesophageal symptoms. The use of this test is aimed at improving the association between patients’ extraoesophageal symptoms and oesophageal or hypopharyngeal acid reflux events. However, the clinical utility of pH monitoring in this patient population remains controversial.

Important clinical questions in this area include: does the presence of abnormal oesophageal acid reflux suggest a causal association between patients’ extraoesophageal symptoms and gastro‐oesophageal reflux disease?

Conversely, does the absence of abnormal acid exposure in the oesophagus suggest lack of such an association? Should the test be performed on or off therapy and does it matter? In this study, the role of pH monitoring in laryngitis, asthma, chronic cough and non‐cardiac chest pain is examined and answers to the above questions are addressed based on current data.
An in vivo internal deletion in the N‐terminus region of Arabidopsis cystathionine γ‐synthase results in CGS expression that is insensitive to methionine
Authors: Hacham Yael , Schuster Gadi , Amir Rachel
Published: February 2006

Cystathionine γ‐synthase (CGS), the first enzyme of methionine biosynthesis in higher plants, plays an important role in the biosynthesis pathway and in regulating methionine metabolism in plant cells. In response to methionine, the expression of this enzyme is regulated via amino acid sequences located in its N‐terminal. Here, using reverse transcription PCR and ribonuclease protection analysis, we demonstrate that, in addition to the full‐length CGS transcript, a deleted form exists in Arabidopsis. The deleted transcript of CGS that lacks 90 or 87 nt located internally in the regulatory N‐terminal region of CGS maintains the reading frame of the protein. Its association with polyribosomes indicates that this deleted form of CGS is translated. In order to study the function of this deleted form of CGS, we overexpressed it in transgenic tobacco plants. We found that the transgenic plants engineered to express only the deleted form of CGS accumulated methionine to a much higher level than those that expressed the full‐length CGS. Furthermore, in vitro feeding experiments revealed that the deleted form of CGS is not subject to feedback regulation by methionine, as reported for the full‐length transcript. Therefore, although most likely produced from the full‐length CGS, the transcript of the deleted form is insensitive to methionine application and its expression may be important for maintaining methionine metabolism even in the presence of a high level of methionine.
Paraneoplastic pemphigus resembling linear IgA bullous dermatosis
Authors: Lee Joyce Siong‐See , Ng Patricia Pei‐Lin , Tao Miriam , Lim Wan‐Teck
Published: February 2006

A 69‐year‐old Chinese man presented in 2001 with a blistering eruption over the upper and lower limbs associated with oral ulceration for 1 month. He had stage IIIA follicular small cell cleaved non‐Hodgkin's lymphoma diagnosed 5 years previously, and had received several lines of palliative chemotherapy, including two courses of chlorambucil, six cycles of cyclophosphamide, adriamycin, vincristine, and prednisolone (CHOP), and two four‐cycle courses of rituximab, with disease stabilization at the time of presentation.

Examination revealed erythematous, annular plaques with raised, urticarial borders studded with tense bullae and vesicles over the thighs. Some lesions were arciform and annular, with vesicles arranged in a ring at the border (Fig. 1). There was involvement of the feet with desquamation at the tips of the toes (Fig. 2). Severe erosions with hemorrhagic crusts on the lips, tongue, and buccal mucosa were seen.

Arciform and annular lesions on the posterior thigh, with vesicles arranged in a ring at the border, resembling the “crown of jewels” seen in linear IgA dermatosis

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Vesicles, pustules, and bullae present on both feet and ankles

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Herpes simplex virus serology was negative. A biopsy specimen from a vesicle on the left thigh showed suprabasal acantholysis (Fig. 3), some apoptotic keratinocytes (Fig. 4), satellite cell necrosis in the epidermis, and a superficial perivascular infiltrate of lymphocytes and eosinophils. Direct immunofluorescence showed intercellular immunoglobulin G (IgG) and C3 within the epidermis and along the basement membrane zone. Indirect immunofluorescence on monkey esophagus was positive for anti‐intercellular antibody at a titre of 1/160 and positive on rat bladder at a titre of 1/80. A presumptive diagnosis of paraneoplastic pemphigus was made. This was later confirmed by the presence of antibodies against envoplakin (210 kDa), periplakin (190 kDa), and desmoglein 1 on immunoprecipitation studies.

Suprabasal acantholysis of the epidermis (arrow). The blister cavity contains fibrin, red blood cells, nuclear debris, and acantholytic keratinocytes (hematoxylin and eosin stain; magnification, ×400)

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A few apoptotic keratinocytes seen in the epidermis (thin arrows). Early suprabasal acantholysis of keratinocytes is present (thick arrows) (hematoxylin and eosin, ×400)

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He was started on prednisolone 60 mg/day (1 mg/kg/day), with complete resolution of skin lesions within 1 week, but persistence of oral ulcers. Cyclophosphamide was added at a low dose of 1 mg/kg/day as he had baseline leukopenia. Cyclosporine was later added to a maximum of 4 mg/kg/day with only mild improvement of the oral lesions. He declined rituximab therapy. He died 2 months later from fulminant pneumonia.
Antibodies against desmoglein 1 in healthy subjects in endemic and nonendemic areas of pemphigus foliaceus (fogo selvagem) in Peru
Authors: Ortega Loayza Alex G. , Ramos Willy , Elgart George , Bouman Peter , Jiménez Gerardo , Avila Jack , Rojas Isabel , Vilcarromero María , Hurtado Jorge , Lindo Gisella , Galarza Carlos
Published: February 2006

Background  Endemic pemphigus foliaceus or fogo selvagem is an autoimmune skin disease characterized by the presence of subcorneal superficial blisters and antibodies of the immunoglobulin G4 (IgG4) class specific for the desmosomal glycoprotein, desmoglein 1. In Peru, no studies have been published on the seroprevalence of antibodies against desmoglein 1 in healthy subjects from endemic foci.

Subjects and methods  This was a cross‐sectional study. The sample included 82 healthy subjects, 41 from the Pueblo Libre community, a focus of endemic pemphigus foliaceus, and 41 from a nonendemic urban area in Pucallpa City. Enzyme‐linked immunosorbent assay (ELISA) was used to determine the presence of antibodies against desmoglein 1. Samples were processed and tested at the Department of Dermatology and Cutaneous Surgery, School of Medicine, University of Miami, Miami, Florida.

Results  It was found that 31.7% of healthy individuals (13 subjects) from the endemic focus had anti‐desmoglein 1 antibodies. A statistically significant association was found between the distance from the endemic focus and the presence of antibodies against desmoglein 1 in subjects living within the endemic focus [Mantel–Haenszel odds ratio (OR), 3.34; P = 0.03; 95% confidence interval (CI), 1.06–10.48]. Agriculture as an occupation showed a statistically significant association with the presence of antibodies against desmoglein 1 (Mantel–Haenszel OR, 7.84; P < 0.001; 95% CI, 2.47–24.87).

Conclusions  Antibodies against desmoglein 1 are present in healthy subjects exposed to an endemic focus of pemphigus foliaceus (fogo selvagem). Agriculture is associated with a high risk of development of antibodies against desmoglein 1 in the endemic focus of the Pueblo Libre community.
Clonidine addition prolongs the duration of caudal analgesia
Authors: Yildiz T. S. , Korkmaz F. , Solak M. , Toker K.
Published: February 2006

Background:  In this study, using a dose‐ranging design, we examined the effects of clonidine with 0.125% bupivacaine on the duration of post‐operative analgesia in caudal anaesthesia in children.

Methods:  We conducted a controlled, prospective study of clonidine in caudal anaesthesia in 60 children, aged 1–10 years, undergoing elective inguinal hernia repair. Induction and maintenance of anaesthesia were performed by inhalation of sevoflurane and nitrous oxide. The children were randomized in a double‐blind fashion to four groups, and were given a caudal anaesthetic with either 0.125% plain isobaric bupivacaine (1 ml/kg) or bupivacaine plus 1, 1.5 or 2 µg/kg of clonidine. The blood pressure and heart rate were recorded peri‐operatively. Analgesia was evaluated by the modified Children's Hospital of Eastern Ontario Pain Scale (mCHEOPS) or a visual analogue scale (VAS). Paracetamol was given when the mCHEOPS score was greater than five or when the VAS score was greater than 30 mm. The monitoring of scores for pain, haemodynamic changes and post‐operative nausea and vomiting was performed by nurses blind to the study allocation.

Results:  The duration of analgesia was found to be significantly longer in the group given bupivacaine plus 2 µg/kg of clonidine (median, 650 min; range, 300–900 min). Peri‐operative hypotension and bradycardia, post‐operative respiratory depression and motor block were not recorded in any patient.

Conclusions:  The addition of clonidine to 0.125% bupivacaine prolongs the duration of post‐operative analgesia without any respiratory or haemodynamic side‐effects.
Effects of high peak airway pressure on the expression of heat shock protein 70 in rat lungs: a preliminary study
Authors: Kira S. , Mori M. , Takatani J. , Uchino T. , Yasuda N. , Miyakawa H. , Noguchi T.
Published: February 2006

Background:  Heat shock protein 70 (HSP70) is induced by a wide variety of stresses in addition to hyperthermia. Recent studies have clarified that mechanical stretching and pressure overload can induce HSP70 in some tissues and cells. However, it remains unclear whether HSP70 is induced in stretch‐subjected lungs, such as those under mechanical ventilation. This study was designed to investigate the effects of high peak airway pressure (PAP) ventilation on HSP70 expression in intact rat lungs.

Methods:  Male Sprague‐Dawley rats were randomly allocated to one of three groups: non‐ventilated (anesthesia alone) control group; PAP 15 cmH2O group (P15); and PAP 30 cmH2O group (P30). The rats in the PAP groups were subjected to pressure‐controlled assisted ventilation at the appropriate PAP for 30 min. Rats were killed at 12, 24 and 48 h after ventilation or anesthesia alone, and the lungs were removed. The lung tissues were processed for immunohistochemical and Western blotting analyses of HSP70.

Results:  Following 30 min of pressure‐controlled assisted ventilation, HSP70 expression in the P30 group was significantly up‐regulated in bronchiolar cells and subepithelial tissues at 12 h, and this up‐regulation continued throughout the observation period. In contrast, there were no significant differences between the control and P15 groups, although the expression of HSP70 was higher in the P15 group than in the control group at all time points.

Conclusions:  HSP70 was induced by high PAP ventilation, but its specific role and induction mechanism remain unclear. Therefore, further investigations should be encouraged.
Thoracic epidural catheters via the caudal and lumbar approaches using styletted multiple port catheters in pediatric patients: a report of three cases
Authors: Tsui B. C. H. , Usher A. , Kulkarni P. R. , Scott S. L.
Published: February 2006

Advancing catheters from the lumbar and caudal epidural spaces to the thoracic level has been reported to be an alternative to the direct thoracic approach. However, as children grow, the threading of catheters in the epidural space becomes increasingly difficult. This report describes three cases of thoracic epidural placement using a multiport catheter threaded from the caudal and lumbar spaces using electrical stimulation guidance. In the first case, a multiport catheter was threaded 22 cm from the lumbar space to T8 following a failed attempt with a single‐port catheter in a 9‐year‐old boy scheduled to undergo a right nephrectomy. In the second case, a multiport catheter was threaded 26 cm from the caudal space to T9 in a 3‐year‐old girl undergoing fundoplication. In the last case, a multiport catheter was inserted at the completion of a fundoplication in a 2‐year‐old girl after it had been confirmed that the single‐port catheter inserted prior to surgery had not advanced to the desired thoracic level. The multiport catheter was threaded 17 cm without resistance from the caudal space to T9. In all cases, electrical stimulation was used to confirm the location of the catheter tip at the time of insertion. The position of the catheters was later confirmed by X‐ray. The multiport catheter incorporates a stylet, which extends to a closed distal tip, within a catheter body that ejects fluid from three lateral holes in a direction perpendicular to the advancing catheter. These properties may facilitate the reliable advancement of catheters in the epidural space.
Neural responses to water surface waves in the midbrain of the aquatic predator Xenopus laevis laevis
Authors: Behrend Oliver , Branoner Francisco , Zhivkov Zhivko , Ziehm Ulrike
Published: February 2006

Many aquatic vertebrates use mechano‐sensory lateral lines to decipher water movements. The peripheral and central organization of the lateral line system has much in common with the auditory system. Therefore, it was hypothesized that the information processing of both systems could be related. Analogous to acoustic objects, for instance, object representations along the central lateral line pathway must be generated from patterns of particle motion across peripheral receivers. Thus, the lateral line offers insight into key features of neural computation beyond a specific sensory system. Here, central processing of water surface waves was described in the African clawed frog which depends on wave signals for prey detection, recognition and localization. Neural responses to surface wave stimuli were recorded in the brainstem and midbrain of Xenopus. A total of 109 units displayed either excitatory or inhibitory responses to surface waves. The response pattern distribution differed significantly across the optic tectum and torus semicircularis magnocellularis (chi‐square test, P < 0.05). Stimulus frequencies from 10 to 40 Hz were represented equally across lateral line nuclei but best frequencies were systematically distributed along the rostrocaudal axis of the midbrain (chi‐square test, P < 0.05). Forty‐one percent of 102 widely distributed units phase locked significantly to stimulus frequencies (Rayleigh test, P < 0.05; vector strength > 0.3) and 41% of 39 tested units featured non‐monotone rate‐level functions. These neurones were registered mainly in the dorsal tectum and magnocellular torus semicircularis (chi‐square test, P < 0.05). Across all tested nuclei, 16 of 17 discreetly distributed units showed a directional response to spatial stimulation. The results suggest midbrain subdivisions with respect to processing of stimulus timing, frequency and amplitude.
Spatial memory deficits in middle‐aged mice correlate with lower exploratory activity and a subordinate status: role of hippocampal neurotrophins
Authors: Francia N. , Cirulli F. , Chiarotti F. , Antonelli A. , Aloe L. , Alleva E.
Published: February 2006

The aim of the present work was to relate age‐related individual differences in cognitive function with behavioural strategies employed in social and non‐social challenges. To this purpose, the behaviour of adult (5‐month‐old) and middle‐aged (13‐month‐old) CD‐1 mice was scored in the social interaction, plus‐maze, Morris water maze (MWM) and open‐field tests. In addition, brain levels of nerve growth factor and brain‐derived neurotrophic factor (BDNF) were analysed and correlated with the behaviours scored. Compared to adults, middle‐aged mice showed greater anxiety in both non‐social and social situations, spending less time in the open arms of the plus‐maze and performing more freezing behaviour in response to aggression. Based upon their behaviour in the social interaction test, adult and middle‐aged subjects were classified as dominant or subordinate and their behaviour in the open field, plus‐maze and MWM tests subjected to factor analysis, taking into account age and social status. Results highlighted meaningful differences in exploratory strategies as a function of social status only in middle‐aged subjects. In particular, middle‐aged dominants were, overall, more explorative than same‐aged subordinates, spending less time in peripheral areas and approaching more readily a novel object. Interestingly, in middle‐aged mice, superior performance in the MWM task was associated with exploratory strategies exploited by dominants. At adulthood, BDNF hippocampal levels, but not specific behaviours, were positively correlated with the ability to learn a spatial task. Overall, data indicate that, in middle‐aged subjects individual differences in exploratory strategies, rather than neurotrophin levels, are able to predict the degree of impairment in a spatial learning task.
Brain‐derived neurotrophic factor enhances expression of superior cervical ganglia clone 10 in lateral geniculate nucleus and visual cortex of developing kittens
Authors: Imamura Kazuyuki , Morii Hiroshi , Nakadate Kazuhiko , Yamada Tomiko , Mataga Nobuko , Watanabe Yasuyoshi , Mori Nozomu
Published: February 2006

Neuronal growth‐associated proteins, including superior cervical ganglia clone 10 (SCG10) family molecules, play roles in neurite outgrowth and network formation as well as structural and functional plasticity. The present ontogenetic study revealed that the expression of neuronal growth‐associated proteins in the visual cortex (VC) exhibited a sharp peak in the early postnatal period when growing lateral geniculate nucleus (LGN) axon terminals segregate into the ocular dominance columns depending on retinal activity. We then hypothesized that SCG10 family molecules, known for catastrophic factors of microtubules, play important roles in the formation of ocular dominance columns. To test this hypothesis, we studied whether: (i) monocular blockade of retinal activity changed the SCG10 expression in LGN and VC and (ii) brain‐derived neurotrophic factor (BDNF) cortical infusion modified the expression of SCG10 family molecules and the number of excitatory/inhibitory cortical synapses. Using northern blot and in situ hybridization, we revealed that: (i) silencing retinal activity with tetrodotoxin eye injections dynamically reduced the expression of SCG10 mRNA and (ii) it was enhanced by BDNF in VC and LGN of kittens but not adult cats. These findings suggest that cortical infusion of BDNF and retinal activity up‐regulate the expression of SCG10 in the LGN and VC and that up‐regulated SCG10 in turn initiates marked reorganization of the microtuble network, eventually resulting in increase in synapse formation in the VC.
Sensory neuronal phenotype in galanin receptor 2 knockout mice: focus on dorsal root ganglion neurone development and pain behaviour
Authors: Shi Tie‐Jun Sten , Hua Xiao‐ying , Lu Xiaoying , Malkmus Shelle , Kinney Jeff , Holmberg Kristina , Wirz Sebastian , Ceccatelli Sandra , Yaksh Tony , Bartfai Tamas , Hökfelt Tomas
Published: February 2006

Galanin is a 29‐amino‐acid peptide expressed in dorsal root ganglion (DRG) neurones and spinal dorsal horn neurones. It affects pain threshold and has developmental and trophic effects. Galanin acts at three G‐protein‐coupled receptors, galanin receptors (GalR1–3), each expressed in the DRGs as suggested by in situ hybridization and/or reverse transcriptase‐polymerase chain reaction. The GalR2 knockout (–/–) mice permit studies on the contributions of this receptor subtype to the role of galanin at the spinal level. At 1 week after sciatic nerve transection (axotomy), there were 16–20% fewer neurones in intact and contralateral DRGs of –/– mice as compared with wild‐type (WT) mice. In addition, a significant neurone loss (26% reduction) was found in the ipsilateral DRGs of WT mice, whereas no further neurone loss was seen in –/– mice. Expression of several peptides has been examined after axotomy, including galanin, neuropeptide Y and two of its receptors as well as substance P, and no significant differences were found between –/– and WT mice in either ipsi‐ or contralateral DRGs, respectively. After thermal injury and spinal nerve ligation, onset and duration of hyperalgesia in the injured paw were similar in GalR2–/– and WT animals. Recovery from spinal nerve ligation‐caused allodynia had the same kinetics in –/– and WT animals. These data are in line with earlier observations from the peripheral and central nervous system, suggesting that galanin actions mediated by GalR2 subtype are of importance in neurodevelopment and neuroprotection.
Expression of planar cell polarity genes during development of the mouse CNS
Authors: Tissir Fadel , Goffinet André M.
Published: February 2006

Atypical cadherin (Celsr3) and the receptor Frizzled3 (Fzd3) are crucial for the development of axonal tracts in the mouse CNS. Celsr3 and Fzd3 are orthologues of the Drosophila‘planar cell polarity’ (PCP) genes flamingo/starry night (fmi/stan) and frizzled, respectively. Reasoning that Celsr3 and Fzd3 might interact with PCP orthologues in mammals like they do in flies, we used mRNA in situ hybridization to compare the expression of Celsr3 and Fzd3 with that of dishevelled 1, 2 and 3 (Dvl1–3), van gogh‐like 1 and 2 (Vangl1, 2), and prickle‐like 1 and 2 (Prickle1, 2), during mouse CNS development, from embryonic day 10.5 to postnatal day 21. With the relative exception of Vangl1, all genes were expressed in the developing CNS. Although Celsr3‐ and Fzd3‐deficient mice have similar phenotypes, Fzd3 expression was more widespread than that of Celsr3. Vangl2 and Dvl2 were preferentially expressed in ventricular zones, in keeping with their role during neural tube closure, where they could be partners of Celsr1. Dvl1 had a broad expression, reminiscent of that of Celsr2, and may be involved in neural maintenance. A large overlap in the expression territories of Dvl genes suggested redundancy. Vangl1 and Prickle1 had expression canvases different from each other and from other candidates, indicating unrelated function. Like Celsr3, Dvl3 and Prickle2 were expressed more strongly in postmitotic neurons than in precursors. Thus, the analogy between the PCP and Celsr3–Fzd3 genetic networks is limited, but may include Dvl3 and/or Prickle2.
Re‐growth of catecholaminergic fibers and protection of cholinergic spinal cord neurons in spinal repaired rats
Authors: Lee Yu‐Shang , Lin Ching‐Yi , Robertson Richard T. , Yu Jen , Deng Xiaoming , Hsiao Ian , Lin Vernon W.
Published: February 2006

The extent of re‐growth of catecholaminergic fibers, the survival of cholinergic neurons and the degree of autonomic dysreflexia were assessed in complete spinal cord‐transected adult rats that received a repair treatment of peripheral nerve grafts and acidic fibroblast growth factor (aFGF). The rats were randomly divided into three groups: (1) sham control group (laminectomy only); (2) spinal cord transection at T8 (transected group); and (3) spinal cord transection at T8, followed by aFGF treatment and peripheral nerve graft (repaired group). The spinal cords and brains of all rats were collected at 6 months post‐surgery. Immunohistochemistry for tyrosine hydroxylase (TH) and dopamine‐β‐hydroxylase (DBH), and fluoro‐gold (FG) retrograde tracing were used to evaluate axon growth across the damage site, and immunocytochemistry for choline acetyl transferase (ChAT) was used to evaluate cholinergic neuronal cell survival following the injury and treatment. When comparing with the transected group, the repaired group showed: (1) lower elevation of mean arterial pressure during colorectal distension; (2) retrogradely labeled neurons in the hypothalamus, zona incerta, subcoeruleus nuclei and rostral ventrolateral medulla following application of FG below the repair site; (3) the presence of TH‐ and DBH‐labeled axons below the lesion site; (4) higher numbers of ChAT‐positive neurons in ventral horn and intermediolateral column near the lesion site. We conclude that peripheral nerve graft and aFGF treatments facilitate the re‐growth of catecholaminergic fibers, also protect sympathetic preganglionic neurons and spinal motor neurons, and reduce autonomic dysfunction in a T‐8 spinal cord‐transected rat model.
Prefrontal and parietal cortex in human episodic memory: an interference study by repetitive transcranial magnetic stimulation
Authors: Rossi Simone , Pasqualetti Patrizio , Zito Giancarlo , Vecchio Fabrizio , Cappa Stefano F. , Miniussi Carlo , Babiloni Claudio , Rossini Paolo M.
Published: February 2006

Neuroimaging findings, including repetitive transcranial magnetic stimulation (rTMS) interference, point to an engagement of prefrontal cortex (PFC) in learning and memory. Whether parietal cortex (PC) activity is causally linked to successful episodic encoding and retrieval is still uncertain. We compared the effects of event‐related active or sham rTMS (a rapid‐rate train coincident to the very first phases of memoranda presentation) to the left or right intraparietal sulcus, during a standardized episodic memory task of visual scenes, with those obtained in a fully matched sample of subjects who received rTMS on left or right dorsolateral PFC during the same task. In these subjects, specific hemispheric effects of rTMS included interference with encoding after left stimulation and disruption of retrieval after right stimulation. The interference of PC‐rTMS on encoding/retrieval performance was negligible, lacking specificity even when higher intensities of stimulation were applied. However, right PC‐rTMS of the same intensity lengthened reaction times in the context of a purely attentive visuospatial task. These results suggest that the activity of intraparietal sulci shown in several funtional magnetic resonance studies on memory, unlike that of the dorsolateral PFC, is not causally engaged to a useful degree in memory encoding and retrieval of visual scenes. The parietal activations accompanying the memorization processes could reflect the engagement of a widespread brain attentional network, in which interference on a single ‘node’ is insufficient for an overt disruption of memory performance.
Enhancement of conditioned fear extinction by infusion of the GABAA agonist muscimol into the rat prefrontal cortex and amygdala
Authors: Akirav Irit , Raizel Hagit , Maroun Mouna
Published: February 2006

In auditory fear conditioning, repeated presentation of the tone in the absence of the shock leads to extinction of the acquired fear response. Both the infra limbic prefrontal cortex (IL) and the basolateral amygdala (BLA) are involved in extinction. In this study, we examine the involvement of these two regions in extinction by manipulating the γ‐aminobutyric acid (GABA)ergic system, in the Sprague–Dawley rat. We microinfused a low dose of the GABAA agonist muscimol into the IL or BLA. Muscimol infused to IL before extinction training, but not after either a short (five‐trials) or long (15‐trials) extinction training, resulted in long‐term facilitation of extinction. Infusion of muscimol to the BLA following a short (five‐trial) extinction session facilitated extinction at least 48‐h post‐drug infusion. The differences in the temporal parameters of the effects of muscimol in the IL or BLA, suggest differential involvement of these structures in long‐term extinction of fear memory. We propose a facilitating role for GABAA neurotransmission in the IL in triggering the onset of fear extinction and its maintenance, whereas in the BLA, GABAA neurotransmission facilitates extinction consolidation. The involvement of GABAA receptors in fear extinction in the prefrontal cortex and amygdala is of particular interest, because of the role of these areas in emotional processes, and the role of the GABAA receptors in anxiety states.
Posttraining lesions of the auditory thalamus, but not cortex, disrupt the inhibition of fear conditioned to an auditory stimulus
Authors: Heldt Scott A. , Falls William A.
Published: February 2006

The purpose of this study was to examine the effects of lesions within the auditory system in an effort to disrupt the processing of the noise stimulus conditioned to inhibit fear. To accomplish this, three experiments were conducted in which rats were first given feature‐negative discrimination training in which a noise was conditioned to inhibit fear to a light that signals danger. Following training, rats were given lesions of the medial geniculate body (MGB), auditory thalamus (ADT), or auditory cortex (CTX). Next, rats were tested for the ability to inhibit fear in the presence of the noise safety signal. The results of these experiments indicated that bilateral lesions of ADT disrupted the ability of the noise inhibitor to inhibit fear. In contrast, lesions largely restricted to the MGB or CTX did not disrupt the inhibition of fear. Along with past studies, these results suggest that an auditory pathway(s), which includes projections from the tectum to the ADT, is used to detect the safety properties previously conditioned to an auditory stimulus.
Differences between the effects of three plasticity inducing protocols on the organization of the human motor cortex
Authors: Rosenkranz Karin , Rothwell John C.
Published: February 2006

Several experimental protocols induce lasting changes in the excitability of motor cortex. Some involve direct cortical stimulation, others activate the somatosensory system and some combine motor and sensory stimulation. The effects usually are measured as changes in amplitude of the motor‐evoked‐potential (MEP) or short‐interval intracortical inhibition (SICI) elicited by a single or paired pulses of transcranial magnetic stimulation (TMS). Recent work has also tested sensorimotor organization within the motor cortex by recording MEPs and SICI during short periods of vibration applied to single intrinsic hand muscles. Here sensorimotor organization is focal: MEPs increase and SICI decreases in the vibrated muscle, whilst the opposite occurs in neighbouring muscles. In six volunteers we compared the after effects of three protocols that lead to lasting changes in cortical excitability: (i) paired associative stimulation (PAS) between a TMS pulse and an electrical stimulus to the median nerve; (ii) motor practice of rapid thumb abduction; and (iii) sensory input produced by semicontinuous muscle vibration, on MEPs and SICI at rest and on the sensorimotor organization. PAS increased MEP amplitudes, whereas vibration changed sensorimotor organization. Motor practice had a dual effect and increased MEPs as well as affecting sensorimotor organization. The implication is that different protocols target different sets of cortical circuits. We speculate that protocols that involve repeated activation of motor cortical output lead to lasting changes in efficacy of synaptic connections in output circuits, whereas protocols that emphasize sensory inputs affect the strength of sensory inputs to motor circuits.
Functional properties and oxidative modulation of A‐type K+currents in hippocampal granule cells of control and chronically epileptic rats
Authors: Rüschenschmidt C. , Chen J. , Becker A. , Riazanski V. , Beck H.
Published: February 2006

A‐type K+channels are crucial determinants of neuronal firing. For example, reducing the amplitude of A‐type currents (IA) increases seizure susceptibility. We have therefore examined the functional and molecular properties ofIAin dentate granule neurons following pilocarpine‐induced status epilepticus (SE).

We found that the levels of various A‐type channel subunit mRNAs are unaltered following SE. Furthermore, current density and biophysical properties ofIArecorded in outside‐out and cell‐attached patches from dentate granule cells are not modified by SE. However,IAin both control and epileptic rats was powerfully regulated by the cellular redox state.IAwas recorded in outside‐out patches with the recording pipette containing either reduced (GSH) or oxidized (GSSG) glutathione. In both control and epileptic rats, the presence of GSSG caused a similar, marked acceleration of recovery from inactivation. Additionally, GSSG produced a small but significant reduction ofIAamplitudes only in control rats. The inactivation time course ofIAduring depolarizing voltage steps was not modified by GSH or GSSG. Cell‐attached recordings, in which the intracellular milieu is conserved, revealed a slow time course of recovery more comparable to that with GSH.

In summary, epileptic activity does not produce chronic changes in the molecular and functional properties of the somaticIAof dentate granule cells. However,IAis powerfully modulated by oxidation in both control and epileptic rats. This finding suggests that the availability ofIAmay be strongly regulated by changes in the GSH/GSSG ratio occurring during prolonged seizure activity or hypoxia.
LRRK2 is expressed in areas affected by Parkinson's disease in the adult mouse brain
Authors: Simón‐Sánchez Javier , Herranz‐Pérez Vicente , Olucha‐Bordonau Francisco , Pérez‐Tur Jordi
Published: February 2006

The leucine‐rich repeat kinase 2 (LRRK2) gene was recently found to have multiple mutations that are causative for autosomal dominant inherited Parkinson's disease (PD). Previously, we used Northern blot analysis to show that this gene was expressed in the cerebellum, cerebral cortex, medulla, spinal cord, occipital pole, frontal lobe, temporal lobe and caudate putamen. However, a more comprehensive map of LRRK2 mRNA localization in the central nervous system is still lacking. In this study we have mapped the distribution of the mRNA encoding for LRRK2 using nonradioactive in situ hybridization. We detected a moderate expression of this PD‐related gene throughout the adult B2B6 mouse brain. A stronger hybridization signal was observed in deep cerebral cortex layers, superficial cingulate cortex layers, the piriform cortex, hippocampal formation, caudate putamen, substantia nigra, the basolateral and basomedial anterior amygdala nuclei, reticular thalamic nucleus and also in the cerebellar granular cell layer. Given that LRRK2 mRNA is highly enriched in motor systems and also is expressed in other systems, we may conclude that mutations in LRRK2 may affect several motor and nonmotor structures that may play an important role in the development of PD.
Potential of a synthetic aggregation pheromone for integrated pest management of Colorado potato beetle
Authors: Kuhar T. P. , Mori K. , Dickens J. C.
Published: February 2006

Abstract 

The relative number of colonizing adult Colorado potato beetles (CPB) Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae) coming to pitfall traps baited with the aggregation pheromone (S)‐3,7‐dimethyl‐2‐oxo‐oct‐6‐ene‐1,3‐diol [(S)‐CPB I] and the use of the pheromone in a trap crop pest management strategy were evaluated in the field for the first time.

More than five‐fold more adult L. decemlineata were caught in pitfall traps baited with the pheromone compared with controls. However, attraction to the pheromone diminished after 5 days in the field.

In the trap crop management strategy, more colonizing adults were present in pheromone‐treated rows of potatoes compared with untreated middle rows.

Significantly fewer L. decemlineata egg masses and larvae were found in potato plots that were bordered by pheromone‐treated rows, or bordered by imidacloprid + pheromone‐treated rows, or rows treated at‐planting with imidacloprid compared with untreated (control) potato plots.

Densities of L. decemlineata egg masses and larvae and percentage defoliation were significantly lower, and marketable tuber yield significantly higher, in conventional imidacloprid‐treated potatoes compared with all other treatments.

Although our results demonstrate the potential for use of the aggregation pheromone in the management of L. decemlineata in the field, more research is needed to optimize the release rates of the attractant and incorporate control methods for cohabiting pests.
The daily egg production method: recent advances, current applications and future challenges
Authors: Stratoudakis Yorgos , Bernal Miguel , Ganias Konstantinos , Uriarte Andrés
Published: February 2006

More than 120 surveys over 25 years suggest that appropriate use of the daily egg production method (DEPM) provides unbiased but rather imprecise estimates of spawning biomass (coefficient of variation generally above 30%). Knowledge of species reproductive biology and early life history and a survey design adapted to local population dynamics are required to optimize DEPM performance in terms of bias, precision and cost. Clupeoid applications dominate worldwide (mainly for anchovies and sardines) and estimates are often used to tune indirect assessment models or to calibrate other fisheries‐independent methods. The method seems better adapted to the life history of anchovies than of sardines, leading to more precise estimates of anchovy spawning biomass and facilitating extensions of the method to estimate total biomass and numbers at age. The continuous underway fish egg sampler is often used as a secondary sampler in the ichthyoplankton survey of the DEPM to reduce the cost and improve the precision of egg production. Multinomial models were recently developed to analyse egg incubation data and used in a Bayesian procedure for egg ageing and delimitation of daily cohorts. These were incorporated in model‐based estimators to get spatially explicit estimates of egg production, daily fecundity parameters and spawning biomass that can improve the precision of DEPM. Uncertainty in daily fecundity estimation of clupeoids is mainly because of spawning fraction estimation by the post‐ovulatory follicle (POF) method. Exploration of recent histological and molecular techniques for POF characterization and laboratory experiments to test the effect of temperature on POF degradation can help to improve spawning fraction estimation. Available estimates of egg production and mortality, daily fecundity, spawning area and biomass from different populations, species and ecosystems are being used to improve the understanding of clupeoid spawning dynamics, their relation with ecosystem productivity and to build comprehensive population models. Finally, a counter‐intuitive finding of this review is that, although the DEPM is almost exclusively applied to clupeoids, recent evidence indicates that it may be easier and cheaper to use in other teleost families, including demersal species.
Mary Shelley's Bestiary: The Last Man and the Discourse of Species
Authors: Williams Cynthia Schoolar
Published: February 2006

This essay won the 2005 Literature Compass Graduate Essay Prize, Romanticism Section.

Mary Shelley's 1826 novel The Last Man richly rewards inquiry through the discourse of species, for it poses the question, “Is the human that which is not the animal?” By subjecting an entire species to the plague, Shelley reveals the extent to which human being is defined over and against the irreducible animal other. In so doing, her text exposes the predation that lies at the root of Western humanism. Considering how Shelley tests the limits of the human, this essay pursues such issues as her handling of the plague itself (for contrary to historical record, the illness in this novel preys only on people) and her critique of the civilizing process that the eponymous narrator undergoes (a process that seems to require the killing of animals and the killing of people as if they are animals). In addition, it traces the decentering of man as the raison d’être of nature and the taxonomic crisis that ensues when Lionel Verney is indeed the sole remnant of humankind. In the twenty‐first century, when the uncontrollable holds the foreground of our own imaginations, Shelley's deployment of the plague – that literalization of all that is incommensurable – speaks to us with renewed force, and the discourse of species offers a particularly useful lens through which to view Shelley's destabilizing of foundational binaries. Drawing on the work of Cary Wolfe, Maureen McLane, Jacques Derrida, and others, this paper argues that Shelley's work offers a radical interrogation of subjectivity itself. Examining the relationship between human and non‐human animals in The Last Man reveals that the novel is more than a critique of imperialism or Romanticism; rather, it is a profound inquiry into the insufficiency of categories, the ephemeral nature of form, and the sacrificial economy that subtends our culture.