bluuebunny/crossref_metadata_2025_split huggingface dataset:
A COMPARISON OF THE PHARMACOLOGICAL PROPERTIES OF RECOMBINANT HUMAN AND RAT α1β2γ2L GABAA RECEPTORS IN XENOPUS OOCYTES
Authors: Rahman Mozibur , Borra Vijaya B , Isaksson Monica , Johansson Inga‐Maj , Ragagnin Gianna , Bäckström Torbjörn , Wang Ming‐De 
Published: April 2008

SUMMARY

In the present study, we compared the pharmacology, particularly neurosteroid modulation of the GABAA receptor, between human and rat a1b2g2L GABAA receptors and between human receptors containing the long (L) and short (S) forms of the g2‐subunit.
We observed that maximum responses to GABA were significantly higher with the human a1b2g2L receptor compared with the rat receptor. In terms of neurosteroid modulation, increases in the EC15 response to GABA induced by 3a‐OH‐5b‐pregnan‐20‐one (3a5bP), 5a‐androstane‐3a,17b‐diol (3a5aADL) and 5a‐pregnane‐3a,20b‐diol (3a5a‐diol) were significantly greater for the rat compared with the human receptor. Responses to 30 mmol/L GABA were inhibited by 3b‐OH‐5a‐pregnan‐20‐one (UC1010) and 5b‐pregnan‐3b,20(R)‐diol (UC1020) to a greater degree for human and rat receptors, respectively. Responses to GABA + 3a5aTHDOC were inhibited by 5a‐pregnan‐3b,20(S)‐diol (UC1019) and pregnenolone sulphate to a greater degree for human and rat receptors, respectively.
The GABA dose–response curves for human a1b2g2S and a1b2g2L receptors were identical. However, the maximum GABA‐evoked current, the direct gating effect of pentobarbital and the allosteric potentiation of the GABA EC15 response by 3a5aTHDOC and 3a5bP were significantly higher with a1b2g2S than a1b2g2L receptors. Inhibition of the response to 30 mmol/L GABA by UC1010 and UC1020 was greater for a1b2g2L and a1b2g2S receptors, respectively. Inhibition of responses to 3a5aTHDOC + GABA by UC1019 and UC1010 was significantly higher for a1b2g2L receptors.
In conclusion, the site of activation by GABA and neurosteroid modulation differ between human and rat a1b2g2L receptors, as well as between human receptors containing the L and S splice variants of the g2‐subunit.
THE CGP7930 ANALOGUE 2,6‐DI‐TERT‐BUTYL‐4‐(3‐HYDROXY‐2‐SPIROPENTYLPROPYL)‐PHENOL (BSPP) POTENTIATES BACLOFEN ACTION AT GABAB AUTORECEPTORS
Authors: Parker David AS , Marino Victor , Ong Jennifer , Puspawati Ni Made , Prager Rolf H 
Published: April 2008

SUMMARY

The pharmacological actions of 2,6‐di‐tert‐butyl‐4‐(3‐hydroxy‐2‐spiropentylpropyl)‐phenol (BSPP), a putative presynaptic GABAB receptor modulator, were examined in electrically stimulated rat neocortical brain slices preloaded with [3H]‐GABA or [3H]‐glutamic acid.
At 10 mmol/L, BSPP inhibited the release of [3H]‐GABA in the presence of baclofen, but not that of [3H]‐glutamic acid. This effect was sensitive to the GABAB receptor antagonist (+)‐(S)‐5,5‐dimethylmorpholinyl‐2‐acetic acid (Sch 50911).
Alone, BSPP had no effect on the release of [3H]‐GABA or [3H]‐glutamic acid.
It is concluded that BSPP selectively potentiates the action of baclofen at GABAB autoreceptors, but not heteroreceptors and may be a useful ligand to discriminate between presynaptic GABAB receptor subtypes.
POST‐RESISTANCE EXERCISE HYPOTENSION IN SPONTANEOUSLY HYPERTENSIVE RATS IS MEDIATED BY NITRIC OXIDE
Authors: Lizardo JHF , Silveira EAA , Vassallo DV , Oliveira EM 
Published: April 2008

SUMMARY

Postexercise hypotension (PEH) plays an important role in the non‐pharmacological treatment of hypertension. It is characterized by a decrease in blood pressure (BP) after a single bout of exercise in relation to pre‐exercise levels.
The present study investigated the effect of a single session of resistance exercise, as well as the effect of nitric oxide (NO) and the autonomic nervous system (ANS), in PEH in spontaneously hypertensive rats (SHR).
Catheters were inserted into the left carotid artery and left jugular vein of male SHR (n = 37) for the purpose of measuring BP or heart rate (HR) and drug or vehicle administration, respectively. Haemodynamic measurements were made before and after acute resistance exercise. The roles of NO and the ANS were investigated by using NG‐nitro‐l‐arginine methyl ester (l‐NAME; 15 mg/kg, i.v.) and hexamethonium (20 mg/kg, i.v.) after a session of acute resistance exercise.
Acute resistance exercise promoted a pronounced reduction in systolic and diastolic BP (–37 ± 1 and –8 ± 1 mmHg, respectively; P < 0.05), which was suppressed after treatment with l‐NAME. The reduction in systolic BP caused by exercise (–37 ± 1 mmHg) was not altered by the administration of hexamethonium (–38 ± 2 mmHg; P > 0.05). After exercise, the decrease in diastolic BP was greater with hexamethonium (–26 ± 1 mmHg; P < 0.05) compared with the decrease caused by exercise alone.
The results suggest that acute resistance exercise has an important hypotensive effect on SHR and that NO plays a crucial role in this response.
A local signature of LTP‐ and LTD‐like plasticity in human NREM sleep
Authors: Bergmann Til Ole , Mölle Matthias , Marshall Lisa , Kaya‐Yildiz Leval , Born Jan , Roman Siebner Hartwig 
Published: April 2008

AbstractPaired associative stimulation (PAS) repeatedly pairs electrical nerve stimulation with transcranial magnetic stimulation of the contralateral motor hand area (M1HAND). Depending on the interstimulus interval, PAS can induce a long‐term potentiation (LTP)‐like facilitation or long‐term depression (LTD)‐like suppression of cortical excitability. In three experimental sessions, 12 awake men received PAS of the right median nerve and left M1HAND in the evening before sleep. To optimize the timing of paired stimulation in M1HAND, the interstimulus interval of PAS was adjusted to the individual N20‐latency of the somatosensory evoked potential to induce LTP‐like effects (PASN20+2ms), LTD‐like effects (PASN20−5ms), or no timing‐dependent after‐effects (PAScontrol). Motor‐evoked potentials (MEPs) showed high interindividual variations in the conditioning effects of PASN20+2ms and PASN20−5ms on cortical excitability. However, PAScontrol allowed us to adjust for any unspecific stimulation effects and the MEP increase after PASN20+2ms differed significantly from the MEP decrease after PASN20−5ms. PASN20+2ms and PASN20−5ms also had a differential effect on regional expression of slow waves and slow spindle activity during the first hour of subsequent non‐rapid eye movement (NREM) sleep. At the electrode sites overlying the conditioned M1HAND and the adjacent premotor cortex, local expression of slow spindle activity was significantly correlated with interindividual differences in the efficacy of PASN20+2ms and PASN20−5ms to potentiate or suppress cortical excitability. This correlation indicates that PAS shapes the local regulation of slow sleep spindles during subsequent NREM sleep.
Coincident pre‐ and postsynaptic activity downregulates NKCC1 to hyperpolarize ECl during development
Authors: Balena Trevor , Woodin Melanie A. 
Published: April 2008

AbstractIn the mature CNS, coincident pre‐ and postsynaptic activity decreases the strength of γ‐aminobutyric acid (GABA)A‐mediated inhibition through a Ca2+‐dependent decrease in the activity of the neuron‐specific K+‐Cl– cotransporter KCC2. In the present study we examined whether coincident pre‐ and postsynaptic activity can also modulate immature GABAergic synapses, where the Na+‐K+‐2Cl– (NKCC1) cotransporter maintains a relatively high level of intracellular chloride ([Cl–]i). Dual perforated patch‐clamp recordings were made from cultured hippocampal neurons prepared from embryonic Sprague–Dawley rats. These recordings were used to identify GABAergic synapses where the reversal potential for Cl– (ECl) was hyperpolarized with respect to the action potential threshold but depolarized with respect to the resting membrane potential. At these synapses, repetitive postsynaptic spiking within ± 5 ms of GABAergic synaptic transmission resulted in a hyperpolarizing shift of ECl by 10.03 ± 1.64 mV, increasing the strength of synaptic inhibition. Blocking the inward transport of Cl– by NKCC1 with bumetanide (10 µm) hyperpolarized ECl by 16.14 ± 4.8 mV, and prevented this coincident activity‐induced shift of ECl. The bumetanide‐induced hyperpolarization of ECl occluded furosemide, a K+‐Cl– cotransporter antagonist, from producing further shifts in ECl. Together, this indicates that brief coincident pre‐ and postsynaptic activity strengthens inhibition through a regulation of NKCC1. This study further demonstrates ionic plasticity as a mechanism underlying inhibitory synaptic plasticity.
Differential effects of pro‐BDNF on sensory neurons after sciatic nerve transection in neonatal rats
Authors: Fan Yong‐jun , Wu Linda Lin‐yan , Li Hong‐yun , Wang Yan‐Jiang , Zhou Xin‐Fu 
Published: April 2008

AbstractBrain‐derived neurotrophic factor (BDNF) plays a critical role in the development of the central and peripheral nervous systems, and also in neuronal survival after injury. The actions of BDNF are mediated by its high‐affinity receptors TrkB and p75NTR. Recent studies have shown that proneurotrophins bind p75NTR and sortilin with high affinity, and trigger apoptosis of neurons in vitro. As proneurotrophins are a dominant form of gene products in developing and adult animals, it is imperative to understand their physiological functions in animals. Here, we showed differential roles of proBDNF in injured and uninjured sensory neurons. proBDNF, p75NTR and sortilin are highly expressed in dorsal root ganglia (DRG) neurons. Recombinant proBDNF induced a dose‐dependent death of PC12 cells and the death activity was completely abolished in the presence of antibodies against the prodomain of BDNF. The exogenous proBDNF enhanced the death of axotomized sensory neurons and the neutralizing antibodies to the prodomain or exogenous sortilin‐extracellular domain‐Fc fusion molecule reduced the death of axotomized sensory neurons. Interestingly, the treatment of neutralizing antibody in vivo increased the number of sensory neurons in the contralateral DRG. We conclude that proBDNF may induce the death of axotomized sensory neurons and suppress neuronal addition in the intact DRG in neonatal rats, and the suppression of endogenous proBDNF may protect neurons after neurotrauma.
Perioperative thromboprophylaxis in children: development of a guideline for management
Authors: JACKSON PHILIP C. , MORGAN JUDITH M. 
Published: April 2008

SummaryBackground:  Venous thromboembolic (VTE) events can occur in children at the time of surgery where a patient has associated prothrombotic risk factors. There is currently little advice available to anesthetists on how to assess the risks and provide prophylaxis.Aim/Objective:  To increase awareness of thrombosis in the perioperative pediatric patient, and to give some guidance when considering prophylaxis in this group.Method/Results:  A guideline outlining risk factors for venous thromboembolism in patients presenting for surgery was written as a flowchart. Recommendations for low risk patients was early mobilization and good hydration; for moderate risk patients having major general surgery to include physical prophylaxis where size permits, i.e. elastic stockings and compression devices; for high‐risk patients undergoing major orthopaedic or general surgery to also receive prophylactic low molecular weight heparin enoxaparin 0.5 mg·kg−1 b.d.Conclusion:  Children with multiple risk factors for VTE should be considered for prophylactic measures when presenting for prolonged major surgery.
Wide genetic diversity of picoplanktonic green algae (Chloroplastida) in the Mediterranean Sea uncovered by a phylum‐biased PCR approach
Authors: Viprey Manon , Guillou Laure , Ferréol Martial , Vaulot Daniel 
Published: April 2008

SummaryThe genetic diversity of picoplanktonic (i.e. cells that can pass through a 3 μm pore‐size filter) green algae was investigated in the Mediterranean Sea in late summer by a culture‐independent approach. Genetic libraries of the 18S rRNA gene were constructed using two different primer sets. The first set is commonly used to amplify the majority of eukaryotic lineages, while the second was composed of a general eukaryotic forward primer and a reverse primer biased towards the phylum Chloroplastida. A total of 3980 partial environmental sequences were obtained: 1668 using the general eukaryotic primer set and 2312 using the Chloroplastida‐biased primer set. Of these sequences, 65 (4%) and 594 (26%) belonged to the Chloroplastida respectively. A 99.5% sequence similarity cut‐off value allowed classification of these 659 Chloroplastida sequences into 74 different operational taxonomic units. A majority of the Chloroplastida sequences (99%) belonged to the prasinophytes. In addition to the seven independent prasinophyte lineages previously described, we discovered two new clades (clades VIII and IX), as well as a significant genetic diversity at the species and subspecies levels, notably among the genera Crustomastix, Dolichomastix and Mamiella (Mamiellales), but also within Pyramimonas and Halosphaera (Pyramimonadales). Such diversity within prasinophytes has not previously been observed by cloning approaches, illustrating the power of using targeted primers for clone library construction. Prasinophyte assemblages differed especially in relation to nutrient levels. Micromonas and Ostreococcus were mainly recovered from mesotrophic areas, whereas Mamiella, Crustomastix and Dolichomastix were mostly detected in oligotrophic surface waters. Within genera such as Ostreococcus or Crustomastix for which several clades were observed, depth seemed to be the main factor controlling differential distribution of genotypes.
A novel, multi‐layered methanotrophic microbial mat system growing on the sediment of the Black Sea
Authors: Krüger Martin , Blumenberg Martin , Kasten Sabine , Wieland Andrea , Känel Layla , Klock Jan‐Hendrik , Michaelis Walter , Seifert Richard 
Published: April 2008

SummaryA novel microbially diverse type of 1‐ to 5‐cm‐thick mat performing anaerobic oxidation of methane (AOM) and covering several square metres of the seafloor was discovered in the Black Sea at 180 m water depth. Contrary to other AOM‐mat systems of the Black Sea these floating mats are not associated to free gas and are not stabilized by authigenic carbonates. However, supply of methane is ensured by the horizontal orientation of the mats acting as a cover of methane enriched fluids ascending from the underlying sediments. Thorough investigation of their community composition by molecular microbiology and lipid biomarkers, metabolic activities and elemental composition showed that the mats provide a clearly structured system with extracellular polymeric substances (EPS) building the framework of the mats. The top black zone, showing high rates of AOM (15 μmol  gdw−1 day−1), was dominated by ANME‐2, while the following equally active pink layer was dominated by ANME‐1 Archaea. The lowest AOM activity (2 μmol  gdw−1 day−1) and cell numbers were found in the greyish middle part delimited towards the sediment by a second pink, ANME‐1‐dominated and sometimes a black outer layer (ANME‐2). Our work clearly shows that the different microbial populations are established along defined chemical gradients such as methane, sulfate or sulfide.
A pyrene‐degrading consortium from deep‐sea sediment of the West Pacific and its key member Cycloclasticus sp. P1
Authors: Wang Baojiang , Lai Qiliang , Cui Zhisong , Tan Tianfeng , Shao Zongze 
Published: April 2008

SummaryA pyrene‐degrading bacterial consortium was obtained from deep‐sea sediments of the Pacific Ocean. The consortium degraded many kinds of polycyclic aromatic hydrocarbons (PAHs), including naphthalene, phenanthrene, pyrene, acenaphthene, fluorene, anthracene, fluoranthene, 2‐methylnaphthalene and 2,6‐dimethylnaphthalene, but it did not grow with chrysene and benzo[α]pyrene. With methods of plate cultivation and polymerase chain reaction–denaturing gradient gel electrophoresis (PCR‐DGGE), 72 bacteria belonging to 22 genera were detected from this consortium. Among the detected bacteria, the following genera frequently occurred: Flavobacterium, Cycloclasticus, Novosphingobium, Halomonas, Achromobacter, Roseovarius and Alcanivorax. The first two genera showed the strongest bands in denaturing gradient gel electrophoresis (DGGE) profiles and appeared in all PAH treatments. By now, only one isolate designated P1 was confirmed to be a pyrene degrader. It was identified to be Cycloclasticus spirillensus (100%). Although P1 can degrade pyrene independently, other bacteria, such as Novosphingobium sp. (Band 14), Halomonas sp. (Band 16) and an unidentified bacterium (Band 35), were involved in pyrene degradation in some way; they persist in the consortium in the test of dilution to extinction if only the consortium was motivated with pyrene. However, the secondary most important member Flavobacterium sp. evaded from the community at high dilutions. As a key member of the consortium, P1 distinguished itself by both cell morphology and carbon source range among the isolates of this genus. Based on intermediate analyses of pyrene degradation, P1 was supposed to take an upper pathway different from that previously reported. Together with the results of obtained genes from P1 homology with those responsible for naphthalene degradation, its degradation to pyrene is supposed to adopt another set of genes unique to presently detected. Summarily, an efficient pyrene‐degrading consortium was obtained from the Pacific Ocean sediment, in which Cycloclasticus bacterium played a key role. This is the first report to exploit the diversity of pyrene‐degrading bacteria in oceanic environments.
Distribution of aerobic anoxygenic phototrophs in temperate freshwater systems
Authors: Mašín Michal , Nedoma Jiří , Pechar Libor , Koblížek Michal 
Published: April 2008

SummaryThe presence of aerobic anoxygenic phototrophs (AAPs) was recently reported from various marine environments; however, there is little information regarding their distribution in fresh waters. We surveyed a number of freshwater systems in central Europe, by infra‐red fluorometry, infra‐red epifluorescence microscopy, fluorescence emission spectroscopy and pigment analyses. AAPs were found to be abundant in several oligotrophic and mesotrophic lakes (50–400 ng of bacteriochlorophyll a l−1, 10–80% of bacterial biomass), while in more eutrophized water bodies they represented a negligible part of the total microbial community (< 1%). The observed freshwater AAPs were morphologically diverse and different from previously observed marine species. Under temperate European climatic conditions, AAP populations undergo strong seasonal changes in terms of both abundance and species composition, with the maximum biomass in summer and the minimum in winter. In the mountain lakes Čertovo and Plešné, AAPs contributed more than one half of total bacterial biomass during their summer maximum. These results show that photoheterotrophic bacteria represent an important part of the microbial community in many freshwater systems.
Use of the rotating wall vessel technology to study the effect of shear stress on growth behaviour of Pseudomonas aeruginosa PA01
Authors: Crabbé Aurélie , De Boever Patrick , Van Houdt Rob , Moors Hugo , Mergeay Max , Cornelis Pierre 
Published: April 2008

SummaryThe biofilm phenotype of Pseudomonas aeruginosa enables this opportunistic pathogen to develop resistance to the immune system and antimicrobial agents. Pseudomonas aeruginosa biofilms are generated under varying levels of shear stress, depending on the infection site. In the lung mucus of cystic fibrosis (CF) patients, P. aeruginosa forms matrix‐enclosed microcolonies which cause chronic infections representing the major cause of mortality in CF patients. The lung mucus of CF patients is probably characterized by low fluid shear as the main shear‐causing factor, i.e. mucociliary clearance, is absent. In this study, the influence of fluid shear on the growth behaviour of P. aeruginosa PA01 was investigated using a low‐shear suspension culture device, the rotating wall vessel (RWV). Cultivation in low shear induced a self‐aggregating phenotype of P. aeruginosa PA01, resulting in the formation of biofilms in suspension similar to what has been described in CF mucus. The addition of a ceramic bead to the culture medium in the RWV created a higher‐shear condition which led to the formation of surface‐attached rather than suspension biofilms. In low‐shear culture conditions, a significant increase of the rhl N‐butanoyl‐l‐homoserine lactone (C4‐HSL) directed quorum sensing (QS) system, and the psl polysaccharide synthetic locus was demonstrated using gene expression analysis. Accordingly, the low‐shear condition induced a higher production of rhamnolipids, which is controlled by the C4‐HSL QS‐system and is known to play a role in CF lung pathology. These results indicate that fluid shear has an impact on the growth phenotype of P. aeruginosa which might play a role in CF lung infections caused by this bacterium.
Ecological biogeography of cephalopod molluscs in the Atlantic Ocean: historical and contemporary causes of coastal diversity patterns
Authors: Rosa Rui , Dierssen Heidi M. , Gonzalez Liliana , Seibel Brad A. 
Published: April 2008

ABSTRACTAim  One of the most recognized ecological paradigms on earth is the increase in species richness from the poles towards the equator. Here we undertake a comprehensive survey of the latitudinal gradients of species richness (LGSR) of coastal cephalopod fauna in the western (WA) and eastern margins (EA) of the Atlantic Ocean, and test climate and non‐climate theories to explain the variation in diversity.Location  The coastal Atlantic Ocean.Methods  The diversity and geographical ranges of coastal cephalopods were investigated by means of an exhaustive survey of the primary literature, reports and on‐line data bases. In order to test the productivity, ambient energy and area hypotheses, we investigated the relationship between diversity and net primary production (NPP), sea surface temperature (SST; measure of solar energy input) and continental shelf area, respectively.Results  LGSR of cephalopod molluscs are present at both Atlantic coasts, but are quite distinct from each other. Historical processes (rise of the Central American Isthmus, formation of ‘Mare Lago’ and glaciations) explained much of the shape and the zenith of LGSR. Contemporary climate and non‐climate variables also each explained over 83% and 50% of the richness variation in WA and EA, respectively, and the best fitted models accounted for > 92% of the variance. By combining latitude with depth a strong Rapoport effect was observed in WA but not in EA.Main conclusions  Besides the evolutionary history, we demonstrate that the contemporary environmental gradients (SST and NPP), shelf area and extent of coral habitat can predict many of the diversity patterns. The longitudinal difference in Rapoport's bathymetric rule is attributed to western fauna specialization to shallow coral reef habitats and greater ecological tolerance of eastern fauna to upwelling ecosystem dynamics. A combined approach of historical biogeography and species–area–energy theories was essential to fully understand broad‐scale variation in cephalopod biodiversity.