bluuebunny/crossref_metadata_2025_split huggingface dataset:
Crustal accretion in and around Iceland
Authors: Steinthorsson S. , Jacoby W. 
Published: April 2008

Since the advent of the new global tectonics, geological problems and processes are being redefined in terms of plate tectonics. This is particularly so in Iceland, which is traversed by the divergent boundary between the Eurasian and North‐American plates and at the same time is a prominent hotspot. Many of the peculiarities of Icelandic geology and geochemistry appear now to be understandable only in these terms, and as a result, investigations in Iceland should shed light on various processes taking place under water along the more inaccessible oceanic ridges.Each period of human history has its own way of looking at the earth. In the Middle Ages, Mount Hekla, Iceland's most famous volcano, was reputed to be the gateway to Hell. Science oftentimes grows more by replacement than by addition, and the Medieval scheme was superseded by a new one which, surprisingly, at times even appeared to hold more questions than answers: Why is Iceland there at all, in the middle of the Atlantic? It looked like an accident of nature. Wegener [1915] interpreted Iceland to be a relic of continental scum left from the separation of Greenland from Europe, although earlier [Wegener, 1912] he had contemplated something similar to seafloor spreading [Jacoby et al., 198O]. H. Hess (personal communication, 1966), one of the pioneers of the new geology, also felt that Iceland did not fit into the idea of seafloor spreading and Belousov [1970] actually used Iceland as a strong argument against that hypothesis.
Application of the intravenous glucose tolerance test and the minimal model to patients with insulinoma: insulin sensitivity (Si) and glucose effectiveness (Sg) before and after surgical excision
Authors: Vethakkan S. R. , Walters J. M. , Gooley J. L. , Boston R. C. , Ward G. M. 
Published: April 2008

SummaryBackground  The unmodified frequently sampled intravenous glucose tolerance test (FSIGT) has not previously been used to assess insulin/glucose kinetics in patients with insulinoma.Objective  To measure insulin sensitivity (Si) and glucose effectiveness (Sg) by means of the FSIGT in patients with insulinoma, before and after surgical removal of the tumour.Subjects and methods  FSIGTs were performed in five patients, before and approximately 3 months post‐surgery, and in 11 controls. Si and Sg were estimated using Minimal Model computer analysis of dynamic glucose and insulin data.Results  Si was lower in insulinoma patients before, compared with after surgery (3·37 ± 0·62 vs. 6·24 ± 1·09 SE [×10−4] min−1µU−1 ml, P < 0·05). Sg was similar in patients pre‐ and post‐surgery (3·0 ± 0·67 vs. 2·4 ± 0·6 [×10−2] min−1, NS).Conclusions  Insulin sensitivity improves after excision of an insulinoma. Glucose effectiveness is not influenced by chronic hyperinsulinaemia and hypoglycaemia.
Regulatory T‐cell expansion and function do not account for the impaired alloreactivity of ex vivo‐expanded T cells
Authors: Montcuquet Nicolas , Mercier‐Letondal Patricia , Perruche Sylvain , Duperrier Anne , Couturier Mélanie , Bouchekioua Abdelghani , Bonyhadi Mark , Ferrand Christophe , Tiberghien Pierre , Robinet Eric 
Published: April 2008

SummaryCD3‐ and CD28‐activated T cells expanded for 12 days ex vivo to produce suicide gene‐modified T cells are hyporesponsive to alloantigens. To investigate whether this impaired alloreactivity is a result of preferential expansion of regulatory T (Treg) cells, we compared peripheral blood mononuclear cells (PBMC) activated with CD3 and CD28 antibodies co‐immobilized on beads and expanded for 12 days with interleukin (IL)‐2 (CoCD3/CD28 cells) to the respective unactivated PBMC in terms of proliferation, cytokine production, and expression of Treg markers [cytotoxic T‐lymphocyte antigen 4 (CTLA4), glucocorticoid‐induced tumour necrosis factor receptor (GITR) and forkhead box P3 (FoxP3)] after allostimulation. Alloreactive cells were identified by carboxyfluoresceine succinimidyl ester staining dilution. Alloreactive cells in CoCD3/CD28 cells had a lower proliferative response and a lower potential for IL‐2 and interferon‐γ secretion than did those in PBMC, demonstrating a functional impairment of alloreactive cells during ex vivo expansion. Expression of Treg markers transiently increased during ex vivo expansion and was unaffected by depletion of CD25+ cells (containing Treg cells) before ex vivo PBMC expansion. Such prior CD25+ depletion did not restore the alloreactivity of CoCD3/CD28 cells. After allostimulation, expression of Treg markers was restricted to proliferative (alloreactive) cells among PBMC or CoCD3/CD28 cells. Lastly, CD4+ CD25+ cells purified from CoCD3/CD28 cells lacked suppressive activity when used as a third party, in contrast to CD4+ CD25+ cells purified from PBMC. In conclusion, the impaired alloreactivity of T cells expanded ex vivo is not a result of preferential Treg cell expansion and/or enhanced suppressive Treg activity.
Identification of two subpopulations of purified human blood B cells, CD27− CD23+ and CD27high CD80+, that strongly express cell surface Toll‐like receptor 9 and secrete high levels of interleukin‐6
Authors: Cognasse Fabrice , Hamzeh‐Cognasse Hind , Lafarge Sandrine , Chavarin Patricia , Pozzetto Bruno , Richard Yolande , Garraud Olivier 
Published: April 2008

SummaryB‐cell expression of certain Toll‐like receptors (TLRs) is important in linking innate and adaptive immune responses in normal and pathological conditions. The expression of TLR9 plays a role in the recognition of conserved pathogen motifs in a manner that is dependent on B‐cell localization, deduced from B‐cell phenotype. The nature of TLR9 function is unclear. A first step in unravelling the function of this pattern recognition receptor is to discover the precise nature of the cell types that express TLR9. This study used three‐colour flow cytometry to characterize the B lymphocytes from human peripheral blood mononuclear cells (PBMCs) that express TLR9 on the surface. We sorted TLR9‐positive B and non‐B cells from the PBMC population and detected TLR9 expression on naïve and memory B cells. Moreover, we identified two discrete subpopulations of B cells: CD19+ CD27− CD23+ cells and CD19+ CD27high CD80+ cells. These subpopulations expressed high levels of membrane TLR9 and exhibited a strong in vitro response to binding a relevant CpG motif by secreting high levels of interleukin‐6 (compared to controls). Our finding that this pattern recognition receptor is expressed on a variety of cell subsets adds to the current understanding of the functional complexity of B‐cell membrane TLR9.
Lymphoid enhancer factor interacts with GATA‐3 and controls its function in T helper type 2 cells
Authors: Hossain Mohammad B. , Hosokawa Hiroyuki , Hasegawa Akihiro , Watarai Hiroshi , Taniguchi Masaru , Yamashita Masakatsu , Nakayama Toshinori 
Published: April 2008

SummaryGATA‐3 is the master transcription factor for T helper 2 (Th2) cell differentiation and is critical for the expression of Th2 cytokines. Little is known, however, about the nature of the functional molecular complexes of GATA‐3. We identified a high‐mobility group (HMG)‐box type transcription factor, lymphoid enhancer factor 1 (LEF‐1), in the GATA‐3 complex present in Th2 cells using a Flag‐calmodulin‐binding peptide (CBP)‐tag based proteomics method. The interaction between GATA‐3 and LEF‐1 was confirmed by co‐immunoprecipitation experiments using LEF‐1‐introduced T‐cell lineage TG40 cells. The HMG‐box domain of LEF‐1 and two zinc finger domains of GATA‐3 were found to be important for the physical association. The introduction of LEF‐1 into developing Th2 cells resulted in the suppression of Th2 cytokine production. The suppression was significantly lower in the cells into which a HMG‐box‐deleted LEF‐1 mutant was introduced. Moreover, LEF‐1 inhibited the binding activity of GATA‐3 to the interleukin (IL)‐5 promoter. These results suggest that LEF‐1 is involved in the GATA‐3 complex, while also regulating the GATA‐3 function, such as the induction of Th2 cytokine expression via the inhibition of the DNA‐binding activity of GATA‐3.
Oral health research with children
Authors: MARSHMAN ZOE , HALL MELANIE J. 
Published: April 2008

Background.  There has been a shift towards research with children and the adoption of the concept of child‐centred research. However, the majority of oral health research is conducted on children, rather than with them.Objective.  This study aimed to provide an overview of contemporary approaches to research with children.Considerations.  The methodological considerations of such research include: the power relationship between the adult researcher and the child participant, with important factors of language use, the setting for the research, appropriate analysis, and quality of the data; ethical factors such as the purpose and risks of the research, confidentiality, recruitment, funding, information to children and parents, consent, and dissemination; and appropriate methods. Methods suitable for oral health research with children include quantitative techniques such as questionnaires and qualitative approaches including interviews individually or in groups and participatory techniques such as time‐lines/life grids, drawings, and vignettes.Conclusion.  There is considerable scope to access children's perspectives of their oral health and care through actively involving them in research. To conduct such research, however, requires training or collaboration with colleagues from other disciplines.
Adults with intellectual disabilities: prevalence, incidence and remission of self‐injurious behaviour, and related factors
Authors: Cooper S.‐A. , Smiley E. , Allan L. M. , Jackson A. , Finlayson J. , Mantry D. , Morrison J. 
Published: April 2008

AbstractBackground  Self‐injurious behaviour (SIB) is a serious condition, with implications for the person, their family and financial costs to the state providing care. The previously reported prevalence of SIB has ranged from 1.7% to 41%, or 1.7%–23.7% in community studies. There has been little study of remission rate, and incidence has not previously been reported. SIB has been reported to be individually associated with lower ability, autism and communication impairments, but given the inter‐relationships between these three factors, it is not known whether they are independently associated with SIB. This study investigates the point prevalence, incidence and remission rates of SIB among the adult population with intellectual disabilities (ID), and explores which factors are independently associated with SIB.Method  A prospective cohort study design was used in a general community setting. The participants were all adults (16 years and over) with ID in a defined geographical area. Individual assessments were conducted with all participants.Results  The point prevalence of SIB (as defined by DC‐LD) was 4.9%, the two‐year incidence was 0.6%, and two‐year remission rate was 38.2%. Independently related to SIB were: lower ability level, not living with a family carer, having attention deficit hyperactivity disorder, visual impairment, and not having Down syndrome. Other factors, including communication impairment, autism, and level of deprivation of the area resided within, were not related.Conclusions  SIB is not as enduring and persistent as previously thought; a significant proportion gains remission in this time period. This should provide hope for families, paid carers and professionals, and reduce therapeutic nihilism. Our study is a first tentative step towards identifying risk‐markers for SIB, and developing aetiological hypotheses for subsequent testing. The extent to which SIB may be a relapsing‐remitting (episodic) condition requires further investigation, so does further hypothesis‐based investigation of factors that might be predictive of incidence of, and remission from, SIB.
The use of melatonin to treat sleep disorder in adults with intellectual disabilities in community settings – the evaluation of three cases using actigraphy
Authors: Dodd A. , Hare D. J. , Arshad P. 
Published: April 2008

AbstractBackground  Sleep disorders are known to be very prevalent in adults with intellectual disabilities (ID) but to date there has been limited objective assessment of either sleep disorders or of interventions such as the use of melatonin.Methodology  A protocol‐driven assessment and intervention procedure was followed with three people with moderate to severe ID identified as having a possible sleep disorder. Actigraphic assessment was used to determine the nature of the sleep disorder, after which sleep hygiene advice and then individual treatment with melatonin were provided, following which further actigraphic assessment was carried out. Behavioural disturbance was formally assessed before and after the intervention phase.Results  Following treatment with melatonin, changes in circadian rhythm were noted, together with improvements in challenging behaviour, but no significant effects were noted with regard to either quantity or quality of sleep.Conclusions  A standardised procedure for assessment and treatment of sleep disorders in people with ID was established. Although no apparent effects on sleep quantity or quality were noted, this may reflect factors inherent in the sample, rather than the relative efficacy of melatonin treatment per se.
No infection with porcine endogenous retrovirus in recipients of acellular porcine aortic valves: a two‐year study
Authors: Gu Chunhu , Wei Xufeng , Wang Yunya , Chen Yu , Liu Jincheng , Wang Hongbin , Sun Guocheng , Yi Dinghua 
Published: April 2008

Abstract:  Background:  Engineered tissue heart valves may become a promising therapeutics for heart valve disease. Compared with synthetic materials, acellular porcine scaffolds are considered as suitable matrices for tissue‐engineered heart valves for the mechanical and structural properties of native tissue. Whether acellular porcine scaffolds can cause infection in recipients with porcine endogenous retrovirus (PERV) is critical for evaluating the safety of transplantation of tissue‐engineered heart valves based on acellular porcine scaffolds. This study was completed to evaluate the risk of PERV transmission for application of acellular porcine aortic valves (PAVs).Methods:  Native aortic valves obtained from Chinese pigs of different species were acellularized by our modified detergent‐enzymatic acellularization procedure. Polymerase chain reaction and reverse transcriptase polymerase chain reaction for pol sequences were used to detect PERV infection. In vitro, ovine endothelial cells (ECs) were inoculated and cocultured with supernatants of porcine aortic endothelial cells (PAECs) and acellualr PAVs, respectively. On 7th day, DNA and RNA of ovine ECs were isolated and tested for PERV. In vivo, acellular PAVs were implanted in the descending thoracic aorta in 40 sheep. Blood samples from the sheep and implanted acellular PAVs were collected 24 months after operation and tested for PERV.Results:  All cells were removed from the PAVs. Acellularized PAVs were repopulated by autologous cells of the host 24 months after implantation. PERV was detected in all native PAVs, porcine blood samples, acellularized PAVs and ovine ECs inoculated with supernatants of PAECs; no PERV was detected in ovine ECs cocultured with acellularized PAVs, ovine blood samples, and implanted acellular PAVs.Conclusions:  Acellularized PAVs processed by modified detergent‐enzymatic acellularization procedure can be used for cardiovascular tissue‐engineered grafts as matrix scaffolds without risk of PERV transmission.
Riluzole blocks persistent Na+and Ca2+currents and modulates release of glutamate via presynaptic NMDA receptors on neonatal rat hypoglossal motoneuronsin vitro
Authors: Lamanauskas Nerijus , Nistri Andrea 
Published: April 2008

AbstractThe neuroprotective agent riluzole is used for the symptomatic treatment of motoneuron disease, which strongly affects the brainstem nucleus hypoglossus. The mechanism of action of riluzole was investigated using, as a model, patch‐clamp recording from hypoglossal motoneurons of the neonatal rat brainstem slice preparation. In the presence of riluzole (10 µm), theta‐rhythm oscillations evoked by nicotine continued even though the persistent inward current (comprising sodium and calcium components) was halved, but they disappeared when the high frequency of spontaneous glutamatergic currents waned. Riluzole fully inhibited the persistent sodium current and partly depressed a tetrodotoxin (TTX)‐insensitive slow current antagonized by Mn2+or Cd2+. Repetitive firing was inhibited by riluzole without changing single action potentials. In the presence of TTX, riluzole depressed miniature glutamatergic currents occurring at high rate. Synaptic transmission with low release probability became sensitive to riluzole if release was stimulated by high potassium solution. Miniature current frequency was depressed by the N‐methyl‐d‐aspartic acid (NMDA) receptor antagonistd‐amino‐phosphonovaleriate (50 µm), which fully occluded the action of riluzole. As riluzole is a protein kinase C (PKC) inhibitor, the PKC antagonist chelerythrine (2.5 µm) mimicked the effect of riluzole and prevented it. In summary, riluzole blocked the persistent sodium current fully, and the calcium one partly, plus it decreased glutamatergic transmission probably via inhibition of PKC that regulated presynaptic NMDA receptors having a facilitatory effect on glutamate release. Controlling NMDA receptor function and, thus, excitatory transmitter release via modulation of PKC suggests a novel potential target to contrast glutamate excitotoxicity in this motor nucleus.
Glomerular activation patterns and the perception of odor mixtures
Authors: Grossman Kimberly J. , Mallik Atul K. , Ross Jessica , Kay Leslie M. , Issa Naoum P. 
Published: April 2008

AbstractOdor mixtures can produce several qualitatively different percepts; it is not known at which stage of processing these are determined. We asked if activity within the first stage of olfactory processing, the glomerular layer of the olfactory bulb, predicts odor mixture perception. We characterized how mice respond to components after training to five different mixture ratios of pentanal and hexanal, and found two types of responses: elemental perception and overshadowing. We then used intrinsic signal imaging to observe glomerular activity in response to the same mixtures and their components. As has been previously described, glomerular activity patterns produced by mixtures resemble the linear combination of responses to components. Mice trained to identify mixtures with more hexanal than pentanal recognized hexanal but not pentanal when the odorants were presented alone (overshadowing). Consistent with these behavioral responses, the imaged activity pattern in response to mixtures was similar to that produced to hexanal alone. Moreover, there was no significant effect of glomerular inhibition in the imaged response. In contrast, the glomerular activity patterns did not predict elemental perception: when trained to identify mixtures with more pentanal than hexanal, mice recognized both components equally well, even with highly overlapping activation patterns. This suggests that spatial activity patterns within the olfactory bulb are not always sufficient to specify component recognition in mixtures.
A possible mechanism for the beneficial effect of ethanol in essential tremor
Authors: Manto M. , Laute M.‐A. 
Published: April 2008

Background: Essential tremor is one of the most common movement disorders in elderly people. The hypothesis of a disregulation ofN‐methyl‐d‐aspartate (NMDA) pathways has been suggested. It was shown experimentally that infusion of NMDA in cerebellar nuclei down‐regulates glutamate release.Methods: We assessed the effects of intranuclear administration of harmaline on the NMDA‐mediated regulation of glutamate in rats using reverse dialysis. We hypothesized that ethanol, which improves essential tremor in the clinic, antagonizes the effect of harmaline upon glutamatergic transmission. We tested the interaction of ethanol and harmaline upon glycerol (a marker of membrane turn‐over), lactate, and pyruvate concentrations.Results: Harmaline increased the concentrations of glutamate and impaired the NMDA‐mediated regulation of glutamate. Ethanol decreased the concentrations of glutamate during NMDA stimulation in case of pre‐administration with harmaline. Concentrations of glycerol rose with harmaline. Glycerol levels markedly decreased during NMDA infusion when inhibitors of nitric oxide synthase, α‐amino‐3‐hydroxy‐5‐methylisoxazole‐4‐propionate antagonists or NMDA antagonists were administered. Harmaline increased lactate/pyruvate ratios during NMDA infusion but these ratios returned to normal values in presence of ethanol.Discussion: We provide a possible mechanism for the beneficial effect of ethanol on essential tremor. The concept of glutamatergic disregulation underlying essential tremor is highlighted. Consequences for our understanding of essential tremor are discussed.
ISOLATION AND CHARACTERIZATION OF THE PHYTOENE DESATURASE GENE AS A POTENTIAL SELECTIVE MARKER FOR GENETIC ENGINEERING OF THE ASTAXANTHIN‐PRODUCING GREEN ALGA CHLORELLA ZOFINGIENSIS (CHLOROPHYTA)1
Authors: Huang Junchao , Liu Jin , Li Yantao , Chen Feng 
Published: April 2008

Phytoene desaturase (PDS) is a rate‐limiting enzyme in carotenoid biosynthesis. Algal PDS is inhibited by some herbicides, leading to the bleaching of the cells due to destruction of chl. Specific point mutations in PDS confer resistance to the herbicide norflurazon, suggesting that mutated PDS could be used as a dominant selectable marker for genetic engineering of algae, for which very few selective markers are available. In this study, we report the isolation and characterization of the PDS gene from the astaxanthin‐producing green alga Chlorella zofingiensis Dönz. The open reading frame (ORF) of this PDS gene, interrupted by six introns, encoded a polypeptide of 558 amino acid residues. The deduced protein sequence showed significant homology to phytoene desaturases of algae, cyanobacteria, and higher plants. Expression of the PDS gene in Escherichia coli demonstrated that the enzyme was able to convert phytoene to ζ‐carotene. The PDS gene in Chlorella was shown to be up‐regulated by high light and glucose treatment. With a single amino acid change (L516R), the mutated PDS‐L516R was still active and exhibited ∼36‐fold greater resistance to the bleaching herbicide norflurazon than the unaltered enzyme. Thus, the modified PDS gene could be a useful tool for genetic engineering of carotenoid biosynthesis in C. zofingiensis and perhaps also in other algae.