bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Discrepancy Between Liquid Phase and Gel Phase Assays for Evaluation of Total Complement Activity and Some Possible Explanations
Authors: Thordardottir S. , Traustadottir K. H. , Erlendsson K. 
Published: June 2004

AbstractThis study was conducted to investigate the frequency and origin of discrepant assay results between two haemolytic assays which both measure activity of the classical pathway of complement (CH50) by haemolysis of sheep red blood cells (SRBCs). One is conducted in gel phase using undiluted sera and the other in liquid phase with sera in 1/100 dilution. The majority of discrepant readings are observed as low or absent haemolysis in the gel phase, with values within or above the normal range in the liquid phase. The incidence of discrepant assay readings was evaluated in 300 samples. Furthermore, 28 samples showing the most discrepant readings were investigated further for disturbing factors. Factors evaluated in the test sera were mannose‐binding lectin, C‐reactive protein (CRP), immune complexes, antibodies to SRBCs, rheumatoid factor and immunoglobulin A (IgA) and IgG anti‐C1q antibodies. The results showed that discrepant readings are present in 10% of the 300 samples and false low gel assay readings account for 6.3%. The majority (68%) of the discrepant samples contained a heat‐stable‐inhibiting factor, and the main mediators found were elevated levels of IgA anti‐C1q antibodies and antibodies to SRBCs. This could indicate a clinically relevant factor in the test sera but can also result from the difference in assay design.
Utility of the Housekeeping Genes 18S rRNA, β‐Actin and Glyceraldehyde‐3‐Phosphate‐Dehydrogenase for Normalization in Real‐Time Quantitative Reverse Transcriptase‐Polymerase Chain Reaction Analysis of Gene Expression in Human T Lymphocytes
Authors: Bas A. , Forsberg G. , Hammarström S. , Hammarström M.‐L. 
Published: June 2004

AbstractThe accuracy of 18S rRNA, β‐actin mRNA and glyceraldehyde‐3‐phosphate dehydrogenase (GAPDH) mRNA as indicators of cell number when used for normalization in gene expression analysis of T lymphocytes at different activation stages was investigated. Quantitative real‐time reverse transcriptase‐polymerase chain reaction was used to determine the expression level of 18S rRNA, β‐actin mRNA, GAPDH mRNA and mRNA for six cytokines in carefully counted samples of resting human peripheral blood mononuclear cells (PBMCs), intestinal lymphocytes and PBMCs subjected to polyclonal T‐cell activation. The 18S rRNA level in activated and resting PBMCs and intestinal lymphocytes was essentially the same, while the levels of β‐actin and GAPDH mRNAs fluctuated markedly upon activation. When isolated γδTCR+, CD4+ and CD8+ subpopulations were studied, 18S rRNA levels remained unchanged after 21 h of activation but increased slightly after 96 h. In contrast, there was a 30–70‐fold increase of GAPDH mRNA/cell in these cell populations upon activation. Cytokine analysis revealed that only normalization to 18S rRNA gave a result that satisfactorily reflected their mRNA expression levels per cell. In conclusion, 18S rRNA was the most stable housekeeping gene and hence superior for normalization in comparative analyses of mRNA expression levels in human T lymphocytes.
Dilemmas and Challenges for the Shelter Sector: Lessons Learned from the Sphere Revision Process
Authors: Saunders Graham 
Published: June 2004

Key dilemmas and challenges for those involved in the shelter sector are described, based on issues that emerged from the extensive global consultative process undertaken to inform the revision of the Sphere handbook. The range of perspectives on the major themes is presented, with suggestions as to how these issues could be progressed.Themes include the poor definition of the sector and the lack of a consistent approach among the leading shelter actors; the absence of a common terminology; the conflict between ‘temporary’ versus ‘durable’ solutions; the disconnect between technical advisers and the field; the need for greater recognition of local coping strategies and the local context; the involvement of recipients and host governments in policy development; the need for better ‘how‐to’ guidance; and the limited incorporation of the emerging themes of livelihoods etc. to date.
An investigation of the role of auditory cortex in sound localization using muscimol‐releasing Elvax
Authors: Smith Adam L. , Parsons Carl H. , Lanyon Richard G. , Bizley Jennifer K. , Akerman Colin J. , Baker Gary E. , Dempster Amanda C. , Thompson Ian D. , King Andrew J. 
Published: June 2004

AbstractLesion studies suggest that primary auditory cortex (A1) is required for accurate sound localization by carnivores and primates. In order to elucidate further its role in spatial hearing, we examined the behavioural consequences of reversibly inactivating ferret A1 over long periods, using Elvax implants releasing the GABAA receptor agonist muscimol. Sub‐dural polymer placements were shown to deliver relatively constant levels of muscimol to underlying cortex for >5 months. The measured diffusion of muscimol beneath and around the implant was limited to 1 mm. Cortical silencing was assessed electrophysiologically in both auditory and visual cortices. This exhibited rapid onset and was reversed within a few hours of implant removal. Inactivation of cortical neurons extended to all layers for implants lasting up to 6 weeks and throughout at least layers I–IV for longer placements, whereas thalamic activity in layer IV appeared to be unaffected. Blockade of cortical neurons in the deeper layers was restricted to ≤ 500 µm from the edge of the implant, but was usually more widespread in the superficial layers. In contrast, drug‐free Elvax implants had little discernible effect on the responses of the underlying cortical neurons. Bilateral implants of muscimol–Elvax over A1 produced significant deficits in the localization of brief sounds in horizontal space and particularly a reduced ability to discriminate between anterior and posterior sound sources. The performance of these ferrets gradually improved over the period in which the Elvax was in place and attained that of control animals following its removal. Although similar in nature, these deficits were less pronounced than those caused by cortical lesions and suggest a specific role for A1 in resolving the spatial ambiguities inherent in auditory localization cues.
An impaired neocortical Ih is associated with enhanced excitability and absence epilepsy
Authors: Strauss Ulf , Kole Maarten H. P. , Bräuer Anja U. , Pahnke Jens , Bajorat Rika , Rolfs Arndt , Nitsch Robert , Deisz Rudolf A. 
Published: June 2004

AbstractNeuronal subthreshold excitability and firing behaviour are markedly influenced by the activation and deactivation of the somato‐dendritic hyperpolarization‐activated cation current (Ih). Here, we evaluated possible contributions of Ih to hyperexcitability in an animal model of absence seizures (WAG/Rij rats). We investigated pyramidal neurons of the somatosensory neocortex, the site of generation of spike–wave discharges. Ih‐mediated functions in neurons from WAG/Rij rats, Wistar rats (sharing the same genetic background with WAG/Rij, but less epilepsy‐prone) and ACI rats (an inbred strain, virtually free of seizures) were compared. We complemented whole‐cell recordings from layer 2–3 pyramidal neurons with immunohistochemistry, Western blot and RT‐PCR analysis of the h‐channel subunits HCN1–4. The fast component of Ih activation in WAG/Rij neurons was significantly reduced (50% reduction in the h‐current density) and four times slower than in neurons from nonepileptic Wistar or ACI rats. The results showing decreases in currents corresponded to a 34% reduction in HCN1 protein in the WAG/Rij compared to the Wistar neocortex, but HCN1 mRNA showed stable expression. The other three Ih subunit mRNAs and proteins (HCN2–4) were not affected. The alterations in Ih magnitude and kinetics of gating in WAG/Rij neurons may contribute to augmented excitatory postsynaptic potentials, the increase in their temporal summation and the facilitation of burst firing of these neurons because each of these effects could be mimicked by the selective Ih antagonist ZD 7288. We suggest that the deficit in Ih‐mediated functions may contribute to the development and onset of spontaneously occurring hyperexcitability in a rat model of absence seizures.
The role of V5 (hMT+) in visually guided hand movements: an fMRI study
Authors: Oreja‐Guevara C. , Kleiser R. , Paulus W. , Kruse W. , Seitz R. J. , Hoffmann K. P. 
Published: June 2004

AbstractElectrophysiological studies in animals suggest that visuomotor control of forelimb and eye movements involves reciprocal connections between several areas (striate, extrastriate, parietal, motor and premotor) related to movement performance and visuospatial coding of movement direction. The extrastriate area MT [V5 (hMT+) in humans] located in the ‘dorsal pathway’ of the primate brain is specialized in the processing of visual motion information. The aim of our study was to investigate the functional role of V5 (hMT+) in the control of visually guided hand movements and to identify the corresponding cortex activation implicated in the visuomotor tasks using functional magnetic resonance imaging. Eight human subjects performed visually guided hand movements, either continuously tracking a horizontally moving target or performing ballistic tracking movements of a cursor to an eccentric stationary target while fixating a central fixation cross. The tracking movements were back‐projected onto the screen using a cursor which was moved by an MRI‐compatible joystick. Both conditions activated area V5 (hMT+), right more than left, particularly during continuous tracking. In addition, a large‐scale sensorimotor circuit which included sensorimotor cortex, premotor cortex, striatum, thalamus and cerebellum as well as a number of cortical areas along the intraparietal sulcus in both hemispheres were activated. Because activity was increased in V5 (hMT+) during continuous tracking but not during ballistic tracking as compared to motion perception, it has a pivotal role during the visual control of forelimb movements as well.
Neuronal activation of Ras regulates synaptic connectivity
Authors: Arendt Thomas , Gärtner Ulrich , Seeger Gudrun , Barmashenko Gleb , Palm Kirstin , Mittmann Thomas , Yan Li , Hümmeke Markus , Behrbohm Julia , Brückner Martina K. , Holzer Max , Wahle Petra , Heumann Rolf 
Published: June 2004

AbstractA synRas mouse model was used expressing constitutively activated Ha‐Ras (Val12 mutation) in neurons to investigate the role of Ras‐MAPkinase signalling for neuronal connectivity in adult brain. Expression of the transgene in the cortex of these mice starts after neuronal differentiation is completed and allows to directly investigate the effects of enhanced Ras activity in differentiated neurons. Activation of Ha‐Ras induced an increase in soma size which was sensitive to MEK inhibitor in postnatal organotypic cultures. Adult cortical pyramidal neurons showed complex structural rearrangements associated with an increased size and ramification of dendritic arborization. Dendritic spine density was elevated and correlated with a twofold increase in number of synapses. In acute brain slices of the somatosensory and of the visual cortex, extracellular field potentials were recorded from layer II/III neurons. The input–output relation of synaptically evoked field potentials revealed a significantly higher basal excitability of the transgenic mice cortex compared to wild‐type animals. In whole cell patch clamp preparations, the frequency of AMPA receptor‐mediated spontaneous excitatory postsynaptic currents was increased while the ratio between NMDA and AMPA‐receptor mediated signal amplitude was unchanged. A pronounced depression of paired pulse facilitation indicated that Ras contributes to changes at the presynaptic site. Furthermore, synRas mice showed an increased synaptic long‐term potentiation, which was sensitive to blockers of NMDA‐receptors and of MEK. We conclude that neuronal Ras is a common switch of plasticity in adult mammalian brain sculpturing neuronal architecture and synaptic connectivity in concert with tuning synaptic efficacy.
Neural correlates of error detection and error correction: is there a common neuroanatomical substrate?
Authors: Fiehler Katja , Ullsperger Markus , Von Cramon D. Yves 
Published: June 2004

AbstractSuccessful behaviour requires error detection resulting in remedial actions, such as immediate error correction. The present event‐related functional magnetic resonance imaging study in humans examined the neural correlates of error detection and error correction using a speeded modified flankers task. In order to investigate corrective behaviour, participants were randomly divided into two groups. The correction instructed group was asked to correct all encountered errors immediately. The correction not instructed group was unaware that corrective responses were recorded. The intention to correct errors significantly increased the correction rate. Brain activations correlating with error detection were isolated in the rostral cingulate zone and in the pre‐supplementary motor area, supporting their important role in error processing. Error correction activated similar brain regions, suggesting a common neuroanatomical substrate. Additional activations were found in the parietal cortex, representing an interconnected cortical network, which processes somatosensory information of tactile stimuli.
Sleep deprivation impairs hippocampus‐mediated contextual learning but not amygdala‐mediated cued learning in rats
Authors: Ruskin David N. , Liu Caiqin , Dunn Kelly E. , Bazan Nicolas G. , LaHoste Gerald J. 
Published: June 2004

AbstractProlonged sleep deprivation results in cognitive deficits. In rats, for example, sleep deprivation impairs spatial learning and hippocampal long‐term potentiation. We tested the effects of sleep deprivation on learning in a Pavlovian fear conditioning paradigm, choosing a sleep deprivation paradigm in which REM sleep was completely prevented and non‐REM sleep was strongly decreased. During conditioning, rats were given footshocks, either alone or paired with a tone, and tested 24 h later for freezing responses to the conditioning context, and to the tone in a novel environment. Whereas control animals had robust contextual learning in both background and foreground contextual conditioning paradigms, 72 h of sleep deprivation before conditioning dramatically impaired both types of contextual learning (by more than 50%) without affecting cued learning. Increasing the number of footshocks did not overcome the sleep deprivation‐induced deficit. The results provide behavioural evidence that REM/non‐REM sleep deprivation has neuroanatomically selective actions, differentially interfering with the neural systems underlying contextual learning (i.e. the hippocampus) and cued learning (i.e. the amygdala), and support the involvement of the hippocampus in both foreground and background contextual conditioning.
Synchronization of gamma oscillations increases functional connectivity of human hippocampus and inferior‐middle temporal cortex during repetitive visuomotor events
Authors: Claudio Babiloni , Martin Bares , Fabrizio Vecchio , Milan Brazdil , Pavel Jurak , Vito Moretti Davide , Alessandra Ubaldi , Maria Rossini Paolo , Ivan Rektor 
Published: June 2004

AbstractDo recency processes associated with repetitive sensorimotor events modulate the magnitude and functional coupling of brain rhythmicity in human temporal cortex? Intracranial stereo electroencephalographic activity (SEEG; 256 Hz sampling rate) was recorded from hippocampus, and inferior (BA20) and middle (BA21) temporal cortex in four epilepsy patients. The repetitive events were represented by predicted imperative somatosensory stimuli (CNV paradigm) triggering hand movements (‘repetitive visuomotor’) or counting (‘repetitive counting’). The non‐repetitive events were ‘rare’ (P3 paradigm) somatosensory stimuli triggering hand movements (‘non‐repetitive visuomotor’) or counting (‘non‐repetitive counting’). Brain rhythmicity was indexed by event‐related desynchronization/synchronization (ERD/ERS) of SEEG data, whereas the functional coupling was evaluated by spectral SEEG coherence between pairs of the mentioned areas. The frequency bands of interest were theta (4–8 Hz), alpha (8–12 Hz), beta (14–30 Hz), and gamma (32–46 Hz). Compared to the non‐repetitive events, the ‘repetitive visuomotor’ events showed a significant beta and gamma ERS in the hippocampus and a significant theta ERD in the inferior temporal cortex. Furthermore, the ‘repetitive visuomotor’ events induced a task‐specific significant gamma coherence among the examined areas. These results suggest that recency processes do modulate the magnitude and functional coupling of brain rhythmicity (especially gamma) in the human temporal cortex.
Intracuneate mechanisms underlying primary afferent cutaneous processing in anaesthetized cats
Authors: Soto Cristina , Aguilar Juan , Martín‐Cora Francisco , Rivadulla Casto , Canedo Antonio 
Published: June 2004

AbstractThe cutaneous primary afferents from the upper trunk and forelimbs reach the medial cuneate nucleus in their way towards the cerebral cortex. The aim of this work was twofold: (i) to study the mechanisms used by the primary afferents to relay cutaneous information to cuneate cuneolemniscal (CL) and noncuneolemniscal (nCL) cells, and (ii) to determine the intracuneate mechanisms leading to the elaboration of the output signal by CL cells. Extracellular recordings combined with microiontophoresis demonstrated that the primary afferent cutaneous information is communicated to CL and nCL cells through AMPA, NMDA and kainate receptors. These receptors were sequentially activated: AMPA receptors participated mainly during the initial phase of the response, whereas kainate‐ and NMDA‐mediated activity predominated during a later phase. The involvement of NMDA receptors was confirmed by in vivo intracellular recordings. The cutaneous‐evoked activation of CL cells was decreased by GABA and increased by glycine acting at a strychnine‐sensitive site, indicating that glycine indirectly affects CL cells. Two subgroups of nCL cells were distinguished based on their sensitivity to iontophoretic ejection of glycine and strychnine. Overall, the results support a model whereby the primary afferent cutaneous input induces a centre‐surround antagonism in the cuneate nucleus by activating (via AMPA, NMDA and kainate receptors) and disinhibiting (via serial glycinergic–GABAergic interactions) a population of CL cells with overlapped receptive fields that at the same time inhibit (via GABAergic cells) other neighbouring CL cells with different receptive fields.
Measurement of coronary flow reserve in isolated hearts from mice
Authors: Bratkovsky S. , Aasum E. , Birkeland C. H. , Riemersma R. A. , Myhre E. S. P. , Larsen T. S. 
Published: June 2004

AbstractAim:  Langendorff‐perfused murine hearts are increasingly used in cardiovascular research, but coronary cardiovascular haemodynamics vary considerably from one research group to another. The aim of this study was to establish an isolated, retrogradely perfused mouse heart preparation for the simultaneous measurement of left ventricular haemodynamics and of coronary flow (CF).Methods:  Heart rate was controlled by right atrial pacing (480 beats min−1) and heart temperature was kept constant. Accurate flow values of <0.5 mL min−1 could be determined, and this methodology was then used to study the stability of this preparation, as well as coronary response to vasoactive drugs and to short‐term ischaemia.Results:  The CF and maximum systolic pressure were well maintained over a 2‐h perfusion period, both showing a 10% decline per hour. Sodium‐nitroprusside (endothelium‐independent) and adenosine (endothelium‐dependent) increased CF relatively modest (30–50% above baseline values). Short‐term no‐flow ischaemia caused a transient 40–50% increase in CF on reperfusion. Peak reflow occurred approximately 15 s after start of reperfusion and flow returned to baseline during the following 1–2 min. Increased coronary blood flow following infusion of vasoactive drugs (nitroprusside or adenosine) or short‐term ischaemia were associated with minor changes in ventricular pressure development.Conclusions:  Blood flow and haemodynamics can readily be determined in this isolated perfused mouse heart model, but CF reserve is relatively small, compared with blood‐perfused organs.
Coexpression after electroporation of plasmid mixtures into muscle in vivo
Authors: Rana Z. A. , Ekmark M. , Gundersen K. 
Published: June 2004

AbstractAim:  Muscle is perhaps the most frequently considered tissue for non‐viral gene therapy, in particular after gene transfer by electroporation. Expression in muscle is stable, but since the cell turnover is so slow incorporation in the host genome is not required. This raises interesting practical and theoretical questions related to the behaviour of the transgenic DNA under such conditions.Methods:  We have investigated expression of reporter genes from plasmid mixtures electroporated into the extensor digitorum longus (EDL) muscle in mice in order to assess the degree of coexpression.Results:  Under conditions where the reporter is easily identified the coexpression rate was 100%, as none of 287 fibres from five different muscles expressing blue fluorescent protein (BFP) failed to express green fluorescent protein (GFP). With other reporter combinations the rate was lower, but this we attribute to marginal sensitivity for fluorescent proteins, or from reporter protein degradation for β‐galactosidase.Conclusions:  The high degree of coexpression suggests that a large copy number takes part in the final transcription with this system. The finding also enhances the usefulness of muscle and electroporation for gene therapy and experimental biology.
Marked Prolongation of Murine Cardiac Allograft Survival Using Recipient Immature Dendritic Cells Loaded with Donor‐Derived Apoptotic Cells
Authors: Xu Dong‐Liang , Liu Yong , Tan Jian‐Ming , Li Bo , Zhong Cui‐Ping , Zhang Xin‐Hua , Wu Chao‐Qun , Tang Xiao‐Da 
Published: June 2004

AbstractWe investigated whether recipient dendritic cells (DCs), pretreated with nuclear factor‐κB oligodeoxyribonucleotide decoy (NF‐κB ODN decoy) and loaded with ultraviolet B‐irradiated donor apoptotic splenocytes (Apo‐SCs), were able to induce murine cardiac allograft tolerance. Heterotopic vascularized heart transplantation was performed from BALB/c to C57BL/6 mice, and recipients (C57BL/6) were given one injection of recipient DCs pretreated with NF‐κB ODN decoy and loaded with donor (BALB/c) apoptotic SCs (decoy Apo‐SCs DCs) through the portal vein at 7 days, before heart transplantation in the absence of immunosuppression. The cardiac allograft survival time and the expressive levels of intragraft cytokine genes [interleukin (IL)‐2, IL‐10, and interferon‐γ] were evaluated. Our results indicated that injection of decoy Apo‐SCs DCs significantly prolonged vascularized heart allograft survival and led to skewing of intragraft cytokine expression towards T helper 2 (IL‐10). The mechanisms can be useful for therapy of allograft rejection with minimization of systemic immunosuppression.