bluuebunny/crossref_metadata_2025 huggingface dataset:
PKC activation sets an upper limit to the functional plasticity of GABAergic transmission induced by endogenous neurosteroids
Authors: Vergnano Angela Maria , Schlichter Rémy , Poisbeau Pierrick
Published: September 2007

The activity of GABAergic inhibitory interneurones located in lamina II of the spinal cord is of fundamental importance for the processing of peripheral nociceptive messages. We have recently shown that 3α‐hydroxy ring A‐reduced pregnane neurosteroids [3α5α‐neurosteroids (3α5αNS)], potent allosteric modulators of GABAAreceptors (GABAARs), are synthesized in the spinal cord and limit thermal hyperalgesia during inflammatory pain. Because changes in the expression of calcium‐dependent protein kinases [protein kinase C (PKC)] are observed during pathological pain in the spinal cord, we examined the possible interactions between PKC and 3α5αNS at synaptic GABAARs. Using patch‐clamp recordings of lamina II interneurones in the spinal cord of 15–20‐day‐old rats, we showed that synaptic inhibition mediated by GABAARs and its modulation by 3α5αNS in lamina II of the spinal cord largely depend on activation of PKC. Our experimental results suggested that activation of PKC locks synaptic GABAARs in a functional state precluding further positive allosteric modulation by endogenous and exogenous 3α5αNS. This effect was fully prevented by coadministration of chelerythrin, an inhibitor of PKC. Furthermore, application of chelerythrin alone rendered synaptic GABAARs hypersensitive to endogenously produced or exogenously applied 3α5αNS. These findings confirmed that there was a significant production of endogenous 3α5αNS in lamina II of the spinal cord but also indicated that PKC‐dependent phosphorylation processes were tonically activated to control GABAAR‐mediated inhibition under resting conditions. We therefore can conclude that PKC activation sets an upper limit to the functional plasticity of GABAergic transmission induced by endogenous neurosteroids.
Variations in glial cell line‐derived neurotrophic factor release from biodegradable nerve conduits modify the rate of functional motor recovery after rat primary nerve repairs
Authors: Piquilloud Gaël , Christen Thierry , Pfister Lukas A. , Gander Bruno , Papaloïzos Michaël Y.
Published: September 2007

Accelerating axonal regeneration to shorten the delay of reinnervation and improve functional recovery after a peripheral nerve lesion is a clinical demand and an experimental challenge. We developed a resorbable nerve conduit (NC) for controlled release of glial cell line‐derived neurotrophic factor (GDNF) with the aim of assessing motor functional recovery according to the release kinetics of this factor in a short gap model. Different types of resorbable NCs were manufactured from a collagen tube and multiple coating layers of poly(lactide‐coglycolide), varying in poly(lactide‐coglycolide) type and coating thickness to afford three distinct release kinetics of the neurotrophic factor. GDNF release was quantified in vitro. End‐to‐end suture and GDNF‐free NC served as controls. Thirty‐five Wistar rats underwent surgery. Motor recovery was followed from 1 to 12 weeks after surgery by video gait analysis. Morphometrical data were obtained at mid‐tube level and distal to the NC. NCs were completely resorbed within 3 months with minimal inflammation. GDNF induced a threefold overgrowth of fibers at mid‐tube level. However, the number of fibers was similar in the distal segment of all groups. The speed of recovery was inversely proportional to the number of fibers at the NC level but the level of recovery was similar for all groups at 3 months. The resorbable conduits proved their ability to modulate axonal regrowth through controlled release of GDNF. In relation to the dose delivered, GDNF strikingly multiplied the number of myelinated fibers within the NC but this increase was not positively correlated with the return of motor function in this model.
Differential expression of members of the RCAN family of calcineurin regulators suggests selective functions for these proteins in the brain
Authors: Porta Sílvia , Martí Eulàlia , De La Luna Susana , Arbonés Maria L.
Published: September 2007

RCANs, also called Down Syndrome Critical Region‐1 (DSCR1)‐like proteins, Modulatory Calcineurin Interacting Proteins (MCIPs) or calcipressins, are regulators of calcineurin, a Ca2+‐dependent protein phosphatase involved in several neuronal functions. Despite the potential importance of the RCAN proteins in brain physiology, very little is known about their relative abundance and distribution patterns in the central nervous system. In this study we report the expression and distribution of RCAN mRNA transcripts and proteins in the mouse brain. RT‐PCR and Western blot analysis showed that all Rcan mRNAs (Rcan1‐1, Rcan1‐2, Rcan2‐1, Rcan2‐3 and Rcan3) and their corresponding protein products (RCAN1‐L, RCAN1‐S, RCAN2‐L, RCAN2‐S and RCAN3) are present in every adult mouse brain region examined. All protein isoforms are also expressed in these same brain regions at early postnatal stages. Within regions, RCAN1‐L, RCAN1‐S, RCAN2‐L and RCAN3 are differentially expressed depending on the region and developmental stage, whereas RCAN2‐S is distributed homogeneously. Detailed immunohistochemical analysis revealed significant differences in the cellular and subcellular distributions of RCAN proteins. In the adult, RCAN1 was mainly expressed in the neuropil throughout the brain. Although at lower levels, RCAN3 was also detected throughout the neuropil. In contrast, RCAN2 was highly expressed in scattered neurons, in both the nucleus and the cytoplasm. Interestingly, RCAN2 is the only member of the RCAN family that was detected in glial cells. Finally, the expression patterns of RCANs at early postnatal stages differed from those of the adult, in different brain areas, in both their distributions and relative abundance, suggesting that the expression of these proteins could be regulated during neuronal differentiation. The nonoverlapping expression patterns of the RCAN proteins shown here highlight the existence of different physiological scenarios and therefore suggest different RCAN functional activities in the brain, depending on the cellular context and developmental stage.
Cellular dynamics underlying regeneration of damaged axons differs from initial axon development
Authors: Blizzard C. A. , Haas M. A. , Vickers J. C. , Dickson T. C.
Published: September 2007

While long‐distance regeneration may be limited in mammalian species, it is becoming apparent that damaged mature neurons retain some capacity for attempted regeneration and that the adult CNS is not entirely inhibitory to axon growth. Our investigations show that there are critical intrinsic features of postinjury axonal regeneration that differ from initial axon development, and that these distinct differences may account for the limited and inappropriate regenerative response that currently characterizes the mature CNS. We compared the neurochemical and dynamic characteristics of developing axons to relatively mature regenerating axons, utilizing an in vitro model of axonal transection to long‐term cultured rat cortical neurons. Immunolabelling studies revealed that regenerating and developing axons have a similar localization of cytoskeletal proteins, but the tips of regenerating axons, although morphologically similar, were smaller with reduced fillopodial extension, relative to developmental growth cones. Live imaging demonstrated that regenerating axons exhibited significantly less outgrowth than developmental neurites. Furthermore, growth cones of regenerating axons had a significant reduction in pausing, considered vital for interstitial branching and pathfinding, than did developmental growth cones. In addition, unlike developing axons, the regenerating axons were unresponsive to the growth factors BDNF and GDNF. Thus, although similar in their cytoskeletal composition, the growth cones of regenerative sprouts differed from their developmental counterparts in their size, their dynamic behaviour and their ability to respond to critical growth factors. These intrinsic differences may account for the inability of post‐traumatic locally sprouting axons to make accurate pathway decisions and successfully respond to trauma.
Domain‐specific retrieval of source information in the medial temporal lobe
Authors: Peters Jan , Suchan Boris , Köster Odo , Daum Irene
Published: September 2007

Memory for context information (source memory) has been reported to rely on structures in the medial temporal lobe (MTL). Perirhinal cortex (anterior MTL) and parahippocampal cortex (posterior MTL) have distinct connectivity patterns with sensory neocortex, suggesting a possible modality‐dependent organization of memory processes. The present study investigated the neural substrates of two different types of source information of newly encoded material using functional magnetic resonance imaging: auditory (speaker voice) and visual (texture and colour). Source judgements during retrieval were reliably above chance level for both modalities and performance did not differ between the auditory and visual condition. During encoding, activity predictive of subsequent source recollection was observed in the anterior hippocampus/parahippocampal gyrus, irrespective of source modality. During retrieval, on the other hand, a regional dissociation emerged: bilateral parahippocampal cortex discriminated between correct and incorrect auditory but not visual source judgements, whereas left perirhinal/entorhinal cortex showed the reverse pattern. These findings are consistent with recent lesion evidence of disrupted auditory but intact visual source memory following damage to the parahippocampal cortex. Results are discussed with respect to anatomical models of corticoparahippocampal connectivity and the functional organization of the MTL.
The involvement of spinal bovine adrenal medulla 22‐like peptide, the proenkephalin derivative, in modulation of nociceptive processing
Authors: Cai Meifang , Chen Tingjun , Quirion Rémi , Hong Yanguo
Published: September 2007

Bovine adrenal medulla 22 (BAM22), one of the cleavage products of proenkephalin A, possesses high affinity for opioid receptors and sensory neuron‐specific receptor (SNSR). The present study was designed to examine the expression of BAM22 in the spinal cord and dorsal root ganglion (DRG) of naive rats as well as in a model of inflammation. BAM22‐like immunoreactivity (BAM22‐IR) was expressed in fibers in the spinal cord, with high density seen in lamina I in naïve rats. The expression of BAM22‐IR in the superficial laminae was greatly reduced following dorsal rhizotomy. BAM22‐IR was also located in 19% of DRG cells, mainly in the small‐ and medium‐sized subpopulations. Following injection of complete Freund's adjuvant (CFA) in the hindpaw, the expression of BAM22‐IR in the superficial laminae of the spinal cord and small‐sized DRG neurons on the ipsilateral side was markedly increased. Double labeling showed that the Fos‐positive nucleus was surrounded by BAM22‐IR cytoplasm in the spinal dorsal horn neurons or closely associated with BAM22‐IR fibers in the superficial laminae. Furthermore, CFA‐induced mechanical allodynia in the inflamed paw was potentiated by intrathecal administration of anti‐BAM22 antibody. Together, these results demonstrate for the first time that BAM22‐like peptide is mainly located in the superficial laminae of the spinal cord and mostly originates from nociceptive DRG neurons. BAM22 could thus act as a ligand for presynaptic opioid receptors and SNSR. Our study also provides evidence suggesting that BAM22 plays a role in the modulation of nociceptive processing at the spinal level under normal and inflammatory conditions.
Acetylcholine‐mediated axon‐glia signaling in the developing insect olfactory system
Authors: Heil Jan E. , Oland Lynne A. , Lohr Christian
Published: September 2007

In the olfactory system of the sphinx moth Manduca sexta, migration of neuropil glial cells is triggered by olfactory receptor axons and depends on intraglial Ca2+ signaling. It is not known, however, how receptor axons and glial cells communicate and whether Ca2+ signaling is a consequence of this communication. We studied Ca2+ increases in glial cells in vivo and in situ, evoked by electrical stimulation of olfactory receptor axons in pupae and by odor stimulation of receptor neurons in adult moths. Axonal activity leads to Ca2+ increases in neuropil glial cells that are blocked by nicotinic acetylcholine receptor antagonists and can be mimicked by acetylcholine and carbachol application. In addition, Ca2+ transients were abolished by removal of external Ca2+ and blockage of voltage‐gated Ca2+ channels. During development, acetylcholine‐mediated Ca2+ signaling could first be elicited at stage 6, the time when neuropil glial cells start to migrate. Glial migration was reduced after injection of nicotinic antagonists into pupae. The results show that Ca2+ signaling can be induced by acetylcholine release from olfactory receptor axons, which activates nicotinic acetylcholine receptors and leads to voltage‐gated Ca2+ influx. The results further suggest that cholinergic signaling in the olfactory system is required for glial cell migration in Manduca.
A brief, but repeated, swimming protocol is sufficient to overcome amyloid β‐protein inhibition of hippocampal long‐term potentiation
Authors: Li Shaomin , Feig Larry A. , Hartley Dean M.
Published: September 2007

Alzheimer's disease starts as an almost imperceptible malady, first observed clinically as a mild memory problem. Accumulating genetic and biochemical data have suggested that amyloid β‐protein (Aβ) plays an important role in this memory loss, and Aβ has been shown to suppress long‐term potentiation (LTP), a cellular model for memory and learning. Here we show that a very brief (3 min) swimming, twice daily for 2 weeks, rescues LTP inhibition in the CA1 region of hippocampal slices caused by Aβ42 or Aβ40 carrying the Arctic mutation using a theta burst stimulation (TBS) protocol. Whereas the input–output curve was not affected, the paired‐pulse ratio was reduced in mice receiving our repeated swimming protocol, suggesting a possible involvement of presynaptic facilitation. Similar to swimming, Aβ's inhibition of LTP could be rescued with the adenylyl cyclase, forskolin. Interestingly, this swimming protocol produced conditions in which a weak‐TBS could invoke LTP not observed in naïve mice, which again was mimicked by forskolin. In contrast, the protein kinase A (PKA) inhibitor, H89, blocked both the forskolin and swimming potentiation of LTP; these data implicate cAMP/PKA signaling in the protective effect of swimming and mediating Aβ′ detrimental effects. Our data add a new simple behavior paradigm that shows the importance of an environmental factor in reversing the pathophysiological effects of Aβ, and suggest new therapeutic avenues.
Differential modulation by monoamine membrane receptor agonists of reticulospinal input to lamina VIII feline spinal commissural interneurons
Authors: Hammar Ingela , Stecina Katinka , Jankowska Elzbieta
Published: September 2007

Noradrenaline and serotonin have previously been demonstrated to facilitate the transmission between descending reticulospinal tracts fibres and commissural interneurons coordinating left–right hindlimb muscle activity. The aim of the present study was to investigate the contribution of subclasses of monoaminergic membrane receptors to this facilitation. The neurons were located in Rexed lamina VIII in midlumbar segments and identified by their projections to the contralateral gastrocnemius–soleus motor nuclei and by lack of projections rostral to the lumbosacral enlargement. The effects of ionophoretically applied membrane receptor agonists [phenylephrine (noradrenergic α1), clonidine (noradrenergic α2), 8‐OH‐DPAT (5‐HT1A, 5‐HT7), 2‐me‐5‐HT (5‐HT3), 5‐me‐5‐HT (5‐HT2) and α‐me‐5‐HT (5‐HT2)] were examined on extracellularly recorded spikes evoked monosynaptically by electric stimulation of descending reticulospinal fibres in the medial longitudinal fascicle. Application of α1 and 5‐HT2 agonists resulted in a facilitation of responses in all investigated neurons while application of α2, 5‐HT1A/7 and 5‐HT3 agonists resulted in a depression. These opposite modulatory effects of different agonists suggest that the facilitatory actions of noradrenaline and serotonin on responses of commissural interneurons reported previously following ionophoretic application are the net outcome of the activation of different subclasses of monoaminergic membrane receptors. As these receptors may be distributed predominantly, or even selectively, at either pre‐ or postsynaptic sites their differential modulatory actions could be compatible with a presynaptically induced depression and a postsynaptically evoked enhancement of synaptic transmission between reticulospinal neurons and commissural interneurons.
The carina is not a landmark for central venous catheter placement in neonates
Authors: INAGAWA GAKU , KA KOUI , TANAKA YUKICHI , KATO KEISUKE , TANAKA MIO , MIWA TAKAAKI , MORIMURA NAOTO , KOYAMA YUKIHIDE , HIROKI KOICHI
Published: September 2007

Background:  Cardiac tamponade is rare but one of the most serious complications in relation to central venous catheters (CVC). The tip of the CVC should be placed outside the pericardium to avoid tamponade. In adults, the carina is always located above the pericardium; therefore, the carina is a reliable landmark for CVC placement. We examined whether the carina could also be an adequate landmark for CVC placement in neonates.

Methods:  The study was conducted using nine fresh neonatal cadavers. The longitudinal distance between the carina and the pericardium as it transverses the superior vena cava (the pericardial reflection: PR) was measured.

Results:  The median postconceptional age (gestational age in weeks + weeks after delivery) at autopsy was 35 (range: 23–42) weeks. The PR was located at a distance of 4 mm above to 5 mm below the carina. Unlike in adults, the position of the PR varies in relation to the carina in neonates. In seven of the nine subjects, the location of the PR was above the carina.

Conclusions:  In neonates, the carina is not always located above the pericardium, as it is in adults; therefore, the carina is not an appropriate landmark for CVC placement.
Standard preoxygenation vs two techniques in children
Authors: CHIRON BRUNO , MAS CHRISTOPHE , FERRANDIÈRE MARTINE , BONNARD CHRISTIAN , FUSCIARDI JACQUES , MERCIER COLETTE , LAFFON MARC
Published: September 2007

Background:  Preoxygenation is recommended in pediatric anesthesia but it has been poorly assessed. Fractional expired oxygen concentration (FETO2) is a preoxygenation monitor. The aim of this prospective study in children was to compare three techniques of preoxygenation by the measurement of FETO2.

Methods:  Twenty children (6–15 years) were included. FETO2 was measured with the child in a supine position, holding the facemask. The FETO2 value was measured after 3 min of calm breathing of room air (baseline) and during the three preoxygenation techniques performed in random order: 3 min of tidal volume breathing using an O2 flow of 9 l·min−1 (TV × 3 min) – four deep breaths within 30 s using an O2 flow of 15 l·min−1 (4 DB) – eight deep breaths within 1 min using an O2 flow of 15 l·min−1 (8 DB). Between each technique, at least 5 min breathing room air was allowed to return to baseline FETO2. Fisher’s exact test was used and P < 0.05 was considered significant.

Results:  Twenty children were studied (age: 11.5 ± 3 years, weight: 42 ± 21 kg). The FETO2 ≥ 90% was found to be 79% in 74 ± 40 s with TV × 3 min, 11% with 4 DB, and 68% with 8 DB.

Conclusions:  In children, Vt × 3 min is the most efficient preoxygenation technique to reach FETO2 ≥ 90%.
A rather unconventional use of the laryngeal mask airway
Authors: NAFIU OLUBUKOLA O. , COKER NICHOLAS
Published: September 2007

Jaw masses are often associated with difficult airway and very often anesthesiologists have to use ingenious but safe techniques to secure the airway. This report is upon awake insertion of the laryngeal mask airway in a patient with a huge jaw tumor.
Anesthetic implications of undiagnosed late onset central hypoventilation syndrome in a child: from elective tonsillectomy to tracheostomy
Authors: MAHMOUD MOHAMED , BRYAN YVON , GUNTER JOEL , KREEGER RENEE N. , SADHASIVAM SENTHILKUMAR
Published: September 2007

Late onset central hypoventilation syndrome is a neurological disorder that can present with postoperative respiratory complications and delayed emergence in children after anesthesia. We present a child who had unanticipated respiratory complications following an elective tonsillectomy who eventually required a tracheostomy and long‐term ventilatory support.
Airway management and anesthesia in neonates, infants and children during endolaryngotracheal surgery
Authors: MAUSSER GERLINDE , FRIEDRICH GERHARD , SCHWARZ GERHARD
Published: September 2007

Background:  Endolaryngotracheal surgery in neonates, infants and children poses a big challenge for both anesthesiologist and surgeon. The narrowness of the airways and the great variability of the pathological lesions necessitate close collaboration between the surgical and the anesthesia team to provide optimal operating conditions and ensure adequate ventilation and oxygenation.

Methods:  Sixty‐two anesthetic records of endolaryngotracheal surgical procedures in neonates, infants and children with ASA physical status 1–3 were analyzed retrospectively. Anesthesia was administered as total intravenous anesthesia; propofol supplemented with remifentanil. Ventilation was performed as supraglottic, superimposed high‐frequency jet ventilation via jet laryngoscope with integrated jet nozzles.

Results:  Age was 58.93 (SD 35.40) months, range 3 weeks to 14 years; body weight 17.83 (SD 8.79) kg, range 2.4–50 kg. The capillary pCO2 5 min after the start of the surgical procedure (n = 62) was 40.01 (SD 7.71) mmHg and after 20 min (n = 24) 41.77 (SD 7.12) mmHg. No hypoxemia (oxygen saturation <90%) developed. All patients were hemodynamically stable during jet ventilation. Barotrauma or gas insufflation in the stomach did not occur. No perioperative tracheostomy was necessary. Laryngospasm occurred in one child during emergence from anesthesia. Four infants received postoperative conventional respirator therapy in the ICU overnight.

Conclusions:  Supraglottic superimposed high‐/low‐frequency jet ventilation via jet laryngoscopes with integrated jet nozzles is a minimally invasive ventilation technique for neonates, infants and children in endolaryngotracheal surgery, which allows an unimpaired operating field for the surgeon especially in LASER surgery.
Amyloid adhesins are abundant in natural biofilms
Authors: Larsen Poul , Nielsen Jeppe Lund , Dueholm Morten Simonsen , Wetzel Ronald , Otzen Daniel , Nielsen Per Halkjær
Published: September 2007

Surface‐associated amyloid fibrils have been described by bacteria in the family Enterbacteriaceae, but it is unknown to what extent amyloid adhesins are present in natural biofilms. In this study, amyloid adhesins were specifically stained with Thioflavin T and two conformationally specific antibodies targeting amyloid fibrils. These three independent detection methods were each combined with fluorescence in situ hybridization using fluorescently labelled oligonucleotide probes in order to link phenotype with identity. Escherichia coli mutants with and without amyloid adhesins (curli) served as controls. In biofilms from four different natural habitats, bacteria producing extracellular amyloid adhesins were identified within several phyla: Proteobacteria (Alpha‐, Beta‐, Gamma‐ and Deltaproteobacteria), Bacteriodetes, Chloroflexi and Actinobacteria, and most likely also in other phyla. Quantification of the microorganisms producing amyloid adhesins showed that they constituted at least 5–40% of all prokaryotes present in the biofilms, depending on the habitat. Particularly in drinking water biofilms, a high number of amyloid‐positive bacteria were identified. Production of amyloids was confirmed by environmental isolates belonging to the Gammaproteobacteria, Bacteriodetes, Firmicutes and Actinobacteria. The new approach is a very useful tool for further culture‐independent studies in mixed microbial communities, where the abundance and diversity of bacteria expressing amyloid adhesins seems much greater than hitherto anticipated.
Microbial community diversity in the phycosphere of natural populations of the toxic alga, Alexandrium fundyense
Authors: Hasegawa Yuko , Martin Jennifer L. , Giewat Michael W. , Rooney‐Varga Juliette N.
Published: September 2007

The dinoflagellate Alexandrium fundyense is the major causative organism of paralytic shellfish poisoning in the Gulf of Maine. While laboratory studies have shown that A. fundyense population dynamics can be affected dramatically by co‐occurring bacteria, little is known about these interactions in nature. Because A. fundyense is typically a minor Gulf of Maine phytoplankton community member, analyses of the bulk community cannot be used to address bacterium–A. fundyense associations. Therefore, an immunomagnetic bead method was used to selectively capture A. fundyense cells, and the bacteria attached to them, from complex natural samples. Bulk particle‐associated and free‐living bacterial communities were collected simultaneously. DNA was extracted from all sample types and subjected to 16S rRNA gene fragment amplification, denaturing gradient gel electrophoresis (DGGE) and sequence analysis. Ordination analysis of DGGE profiles confirmed that A. fundyense‐associated bacteria community profiles were distinct from bulk bacterial community profiles, indicating selection of specific phylotypes in the A. fundyense phycosphere. Phylogenetic analyses confirmed that Alexandrium‐associates were distinct from bulk particle‐associated bacteria and that they included a greater prevalence and broader diversity of Gammaproteobacteria than previously thought to be associated with toxic algae. Phylogenetic groups known to be associated with dinoflagellates were also found, including members of the families Alteromonadaceae, Pseudoalteromonadaceae, Rhodobacteraceae and Flavobacteraceae.
Identification of novel perchloroethene‐respiring microorganisms in anoxic river sediment by RNA‐based stable isotope probing
Authors: Kittelmann Sandra , Friedrich Michael W.
Published: September 2007

The halogenated compound tetrachloroethene (perchloroethene, PCE) is a persistent contaminant of aquifers, soils and sediments. Although a number of microorganisms are known to reductively dechlorinate PCE by dehalorespiration, their diversity and community structure especially in pristine environments remain elusive. In this study, we report on the detection of a novel group of dehalorespiring bacteria that reductively dechlorinate PCE to cis‐dichloroethene by RNA‐based stable isotope probing. Pristine river sediment was incubated at 15°C with PCE at low aqueous concentration. Upon formation of dechlorination products, the microbial community was probed with 13C‐labelled acetate as electron donor and carbon source. Terminal restriction fragment length polymorphism (T‐RFLP) analysis of density‐separated 16S rRNA revealed a predominantly 13C‐labelled bacterial population only in the microcosm with PCE in high‐density gradient fractions, whereas in the control without PCE Bacteria‐specific rRNA was restricted to light gradient fractions. By cloning and sequence analysis of 16S rRNA, the predominant population was identified as a novel group of bacteria within the phylum Chloroflexi. These microorganisms, designated Lahn Cluster (LC), were only distantly related to cultivated dehalorespiring Dehalococcoides spp. (92–94% sequence identity). Minor clone groups detected 13C‐labelled and thus, potentially involved in PCE dehalorespiration, were related to β‐proteobacterial Dechloromonas spp., and δ‐Proteobacteria (Geobacteraceae, Desulfobacteraceae, Desulfobulbaceae). In contrast, clones from an ethene‐producing microcosm incubated at 20°C grouped with known Dehalococcoides spp. Our results show that stable isotope probing allows targeting dehalorespiring bacteria as functional guild, and to identify novel PCE‐respiring populations previously not recognized.
Modifying lysine biosynthesis and catabolism in corn with a single bifunctional expression/silencing transgene cassette
Authors: Frizzi Alessandra , Huang Shihshieh , Gilbertson Larry A. , Armstrong Toni A. , Luethy Michael H. , Malvar Thomas M.
Published: September 2007

Although it is one of the major crops in the world, corn has poor nutritional quality for human and animal consumption due to its low lysine content. Here, we report a method of simultaneous expression of a deregulated lysine biosynthetic enzyme, CordapA, and reduction of a bifunctional lysine degradation enzyme, lysine‐ketoglutarate reductase/saccharophine dehydrogenase (LKR/SDH), in transgenic corn plants by a single transgene cassette. This is accomplished by inserting an inverted‐repeat sequence targeting the maize LKR/SDH gene into an intron of a transgene cassette that expresses CordapA. This combination of LKR/SDH silencing and CordapA expression led to the accumulation of free lysine to over 4000 p.p.m. in transgenic corn grain, compared to less than 100 p.p.m. in wild‐type controls. This intron‐embedded silencing cassette design reduces the number of transgene cassettes needed in transgenic approaches for manipulating metabolic pathways that sometimes require expression of one gene and silencing of another.
Rethinking lifelong learning through online distance learning in Chinese educational policies, practices and research
Authors: Yang Min
Published: September 2007

This paper offers a critique of the Chinese philosophy of online distance learning as a means of building a lifelong learning society. Literature about lifelong learning and its implications for online distance learning is reviewed. Documents, reports and research papers are examined to explore the characteristics of the Chinese philosophy of online distance learning as reflected in the prevailing understanding and debates in the field. Phenomenological analysis, deconstructive discourse analysis and internal criticism are employed, guided by a phenomenological qualitative methodology. The critique reveals that the notion of lifelong learning is to some extent obscured in meaning in the prevailing understanding of and debates about Chinese online distance learning. Furthermore, it shows that the Chinese philosophy of online distance learning paradoxically combines a sense of overenthusiasm with a sense of underestimation associated with the potential of online distance learning in promoting lifelong learning. Also identified is the emerging development of Chinese online distance learning towards its ‘in‐depth development’, based on an increasing awareness of the necessity to enhance the quality of online distance learning through integration of educational theories with information and communication technologies (ICT). The paper calls for a new vision on ICT for learning as a necessary condition for successful incorporation of Chinese online distance learning with and into lifelong learning.
An investigation of user perceptions and attitudes towards learning objects
Authors: Lau Siong‐Hoe , Woods Peter C.
Published: September 2007

This study empirically evaluates the technology acceptance model drawn from Information Systems (IS) literature to investigate how user beliefs and attitudes influence learning‐object use among higher education learners by evaluating the relationships between perceived usefulness, perceived ease of use, attitude, behavioural intentions and actual use. In the study, 601 potential learning‐object users were presented with an introductory demonstration of learning objects for a Digital Systems course. Following the demonstration and practice, data on user beliefs, attitudes and intention to use learning objects were gathered, while data on actual use of learning objects was collected at the end of the semester. Subjects with prior experience using the learning objects were eliminated from further analysis, resulting in a final sample of 481 users. structural equation modelling was employed to test the hypothesised study model. The analysis showed that both the user beliefs and attitudes have significant positive relationships with behavioural intention and that behavioural intention accurately predicted the actual use of learning objects. The results extend the validity of the TAM into a learning object context and clearly pointed out that it can be used to predict users’ future behaviour.
China's Energy Security and Eurasian Diplomacy: The Case of Turkmenistan
Authors: Lanteigne Marc
Published: September 2007

China has made significant strides in developing energy diplomacy in the former Soviet states of Central Asia in the name of diversifying its trading partners. However, the case of Turkmenistan, currently undergoing a complicated leadership transition, provides evidence of China's potential limitations in engaging Central Asia in the hopes of securing nearby sources of oil and gas. The ongoing problems of post-Soviet governance in Ashgabat and increasing competition for Turkmen natural gas suggest that Beijing may have to better define its economic interests there and allow for increased regional co-operation building to better manage its Central Asian energy trade.
Deepening the Human Security Debate: Beyond the Politics of Conceptual Clarification
Authors: Ewan Pauline
Published: September 2007

‘Human security’ has been framed as a transformative project that seeks to reinvent the theory and practice of security beyond the national security priorities of states. Central to this project is a holistic and people-centred approach that broadens the concept of security and problematises the view that the security concerns of individual men and women are best served by the security policies of their states. Yet although these ideas have gained ground in policy circles, the academic literature in this area has been dominated by debates about the merits and demerits of human security's expansion of the contemporary security agenda. This article explores two key objections to the holistic character of human security and argues that critics underestimate the politics involved in delimiting this concept. In order to deepen our understanding of the politics of human insecurity, human security scholarship must move beyond its current preoccupation with narrow forms of conceptual clarification.
Misguided Policies in the War on Terror? The Case for Disentangling Terrorist Financing from Money Laundering
Authors: Roberge Ian
Published: September 2007

In the war on terror governments have sought to tackle the issue of terrorist financing by building on the pre-existing regime against money laundering. The article argues that although there are similarities between money laundering and terrorist financing, there are also important differences between these illegal financial activities. Money laundering is ultimately about safeguarding profits, while terrorist financing aims to support groups with violent political objectives. The article suggests that each threat would be best addressed by the use of targeted strategies.
Class Size, Teacher Hours and Educational Attainment*
Authors: Browning Martin , Heinesen Eskil
Published: September 2007

We employ a regression‐discontinuity design to identify effects on educational attainment after compulsory school of class size and the number of pupils per weekly teacher hour using administrative rules as instruments. We use Danish administrative panel data. Average class size is 20, about the same as in the US and most European countries. Restricting the sample to observations close to the enrolment discontinuity points where the administrative rules have greatest predictive power, instrumental variables estimates are consistently negative. Estimates from the preferred specification are marginally significant and indicate modest effects in line with earlier studies. Estimates for subgroups are less precise, but they indicate larger effects for pupils from less advantaged backgrounds.
On the Coexistence of Banks and Markets*
Authors: Gersbach Hans , Uhlig Harald
Published: September 2007

We examine the coexistence of banks and financial markets by studying a credit market where the qualities of investment projects are not observable and the investment decisions of entrepreneurs are not contractible. Standard banks can alleviate moral‐hazard problems, while financial markets operated by investment banks can alleviate adverse‐selection problems. In competition, standard banks are forced to increase repayments, since financial markets can attract the highest‐quality borrowers. This, in turn, increases the share of shirkers and may make lending unprofitable for standard banks. The coexistence of financial markets and standard banks is socially inefficient. The same inefficiency may occur with the entrance of sophisticated banks, operating with a combination of rating and ongoing monitoring technologies.
Optimal Monetary Policy and Sectoral Shocks: Is International Monetary Cooperation Beneficial?
Authors: Berger Wolfram
Published: September 2007

A stochastic general‐equilibrium model is used to explore the welfare effects of optimal monetary policy and the potential benefits of policy coordination. Cross‐country perfectly symmetric shocks in the traded goods sectors and imperfectly correlated shocks in the non‐traded goods sectors are considered. In this set‐up, monetary policy may not be able to achieve efficient sectoral resource allocations within countries and avoid inefficient relative price changes across countries. Welfare gains from coordination are sizable if the shocks to the traded and non‐traded goods sectors are negatively correlated and both sectors are of roughly equal size.
Contests with Multi‐tasking*
Authors: Clark Derek J. , Konrad Kai A.
Published: September 2007

The standard contest model in which participants compete in a single dimension is well understood and documented. Multi‐dimension extensions are possible but are liable to increase the complexity of the contest structure, mitigating one of its main advantages: simplicity. In this paper we propose an extension in which competition ensues in several dimensions, and a competitor that wins a certain number of these is awarded a prize. The amount of information needed to run the contest is hence limited to the number of dimensions won by each player. We look at the design of this contest from the point of view of maximising effort in the contest (per dimension and totally), and show that there will be a tendency to run small contests with few dimensions. The standard Tullock model and its results are encompassed by our framework.
Early Starts, Reversals and Catch‐up in the Process of Economic Development*
Authors: Chanda Areendam , Putterman Louis
Published: September 2007

Early states like China and India have been experiencing more rapid economic growth in recent decades. We show that more rapid growth by early starters has been the norm in economic history, and that the “reversal of fortune” associated with the European overseas expansion was both exceptional and temporary. Not only was the post‐1500 reversal in the process of being reversed after 1960, but also the advantage conferred by early development in the latter period was considerably greater than the growth rate disadvantage that it conferred during 1500–1960, implying a rapid undoing of the first reversal.
Financial Instability under a Flexible Exchange Rate*
Authors: Besancenot Damien , Vranceanu Radu
Published: September 2007

Many governments in developing countries contemplate the possibility of increasing the flexibility of their exchange rates despite having accumulated substantial dollar‐denominated debt. Using a model of corporate dollar debt in which the future exchange rate is uncertain, this paper studies the financial risks that might arise as a consequence of increased exchange rate flexibility. Since a firm may default on its debt either because its dollar income is too low or because investors refuse to roll over its debt, the measure of the overall risk of default should take into account both factors, as well as their interaction. Solving the model for the no‐default rational expectations equilibrium, we find that a small risk of insolvency may bring about a substantial risk of illiquidity.
Do Antitrust Laws Facilitate Collusion? Experimental Evidence on Costly Communication in Duopolies*
Authors: Andersson Ola , Wengström Erik
Published: September 2007

Bertrand supergames with non‐binding communication are used to study price formation and stability of collusive agreements on experimental duopoly markets. The experimental design consists of three treatments with different costs of communication: zero‐cost, low‐cost and high‐cost. Prices are found to be significantly higher when communication is costly. Moreover, costly communication decreases the number of messages, but more importantly, it enhances the stability of collusive agreements. McCutcheon (1997) presents an interesting application to antitrust policy by letting the cost of communication symbolize the presence of an antitrust law that prohibits firms from discussing prices. Although our experimental results do not support the mechanism of McCutcheon's (1997) argument, the findings point in the direction of her prediction that antitrust laws might work in the interest of firms.
Identifying the poor in the 1870s and 1880s1
Authors: GILLIE ALAN
Published: September 2007

Poverty lines devised throughout England and Wales in the 1870s and 1880s defined ‘the poor’, a new class not recognized by the poor law. This article provides an account of the poverty lines adopted, mainly by school boards, in about 40 different places; the context in which they were developed; and what has been retrieved of the reasons determining the adoption of specific poverty lines. In particular, it examines the principal controversies surrounding them, and the challenge they posed to the poor law; and, incidentally, compares them to the poverty lines proposed, many years later, by Booth and Rowntree.
New estimates of age‐ and sex‐specific earnings and the male–female earnings gap in the British cotton industry, 1833–19061
Authors: BOOT H. M. , MAINDONALD J. H.
Published: September 2007

This article introduces a new set of estimates of average weekly age‐ and sex‐specific earnings paid at each year of age between 13 and 60 years of age to males and females employed in the British cotton industry between 1833 and 1906. As one example of the use of the estimates, the article shows how the estimates provide insights into changes in the male–female earnings gap in one key industrial group of workers in Victorian Britain. An appendix provides estimates of the population‐weighted average weekly full‐time money earnings of British cotton operatives, in pence per week, by sex, of the age groups: <13, 13–17, 18–60+, and 13–60+.
Spontaneous Adaptation in Public Management: An Overview
Authors: CAMPBELL COLIN
Published: September 2007

This collection addresses the issue of why it so often proves difficult to foster innovation in public management. Specifically, it focuses its attention on why reform efforts encounter so frequently intractable obstacles stemming from the erosion of the mutual regard among political executives and career officials for the integrity of each others' respective competences in the devising of policies and the crafting and implementation of decisions based upon these.
Advocacy and Innovation in Interagency Management: The Case of Centrelink
Authors: HALLIGAN JOHN
Published: September 2007

Two basic principles of public organization have been the strength of the functional principle as the basis for most central government organization and the direct control of the ministerial department over delivery of big‐budget social services. Both were challenged in the 1990s as the combined impact of new public management and customer service suggested new ways of handling these questions. One result was a new type of agency that combined the functional separation of delivery and purchaser–provider from new public management, but also horizontal integration of delivery. This creative design seemed to offer solutions to specific problems, but it also produced tensions with others arising from governance issues and the complexities entailed in the connections between specialization and coordination.
Pressure, Legitimacy, and Innovative Behavior by Public Organizations
Authors: VERHOEST KOEN , VERSCHUERE BRAM , BOUCKAERT GEERT
Published: September 2007

According to New Public Management (NPM) doctrines, public organizations involved in service delivery and policy implementation will be induced to innovative behavior if they have enough managerial autonomy and simultaneously are subjected to managerial pressure, such as result control by government or competition of other providers. This NPM pressure‐response model is tested by using survey data on 84 Flemish public organizations. These tests provide evidence for the assumed effect of NPM‐like pressure on the innovative behavior of public organizations. However, the empirical model shows more complex relationships as is assumed by NPM doctrine. These complex relationships are corroborated and explained by making reference to a multiple‐case study of four Flemish public organizations. An expanded political/administrative pressure‐response model, referring to legitimacy as a motivational force, is suggested in order to explain innovative behavior by public organizations. This model may help to understand the preconditions for spontaneous adaptation of public organizations.
Learning from Second‐Hand Experience: Methodology for Extrapolation‐Oriented Case Research
Authors: BARZELAY MICHAEL
Published: September 2007

Critics of public management reform complain that governments copy legitimated foreign practices. Recent work by Eugene Bardach helps to explain why: neither government analysts nor academic researchers possess an adequate methodology to examine practices in source sites, with a view toward adaptation in target sites. Rather than complain, Bardach takes steps to develop such a methodology, drawing analogies with reverse engineering. This article offers specific guidance about how researchers can effectively investigate practices in source sites to prepare the ground for disciplined and ingenious extrapolation of practices from source to target sites. The resulting translation is illustrated by an extrapolation‐oriented case study.
Effect of single mannitol bolus in intracerebral hemorrhage
Authors: Misra U. K. , Kalita J. , Vajpayee A. , Phadke R. V. , Hadique A. , Savlani V.
Published: September 2007

Because of existing controversy about use of mannitol in intracerebral hemorrhage (ICH) this open exploratory trial with blinded outcome assessment of single mannitol bolus in ICH was undertaken. CT proven primary supratentorial ICH patients having midline shift of ≥3 mm were randomized into 20% mannitol (1.5 g/kg) and control groups. Clinical evaluation included Glasgow coma scale (GCS) score, Canadian Neurological scale (CNS) score, pupils, breathing, extensor posturing and contra‐lateral pyramidal signs. On cranial MRI horizontal (HS), superior sagittal sinus to pontomesencephalic junction (SSS‐PMJ) distance and edema hematoma complex were measured. Twelve patients each were in mannitol and control groups. The age, sex, GCS score, CNS score, pupillary asymmetry, contra‐lateral pyramidal signs, HS and SSS‐PMJ distance in mannitol and control groups did not differ significantly. Mannitol infusion resulted clinical improvement in five patients, which lasted for 30–60 min. HS and SSS‐PMJ distance in mannitol and control groups did not change at 30 or 60 min from the baseline. The change in HS and SSS‐PMJ distance were also not significantly different between the two groups both at 30 and 60 min. Mannitol led to transient clinical improvement in five patients without significant reduction in HS or SSS‐PMJ distance at 30 and 60 min.