bluuebunny/crossref_metadata_2025 huggingface dataset:
Plant secondary siRNA production determined by microRNA-duplex structure
Authors: Manavella Pablo A. , Koenig Daniel , Weigel Detlef
Published: January 2012

Processing of microRNA (miRNA) precursors results in the release of a double-stranded miRNA/miRNA* duplex. The miRNA or guide strand, is loaded onto the Argonaute (AGO) effector, and the miRNA* or passenger strand is typically degraded. The loaded AGO-containing RNA-induced silencing complex specifically recognizes a target mRNA, leading to its degradation or translational inhibition. In plants, miRNA-mediated cleavage of a target triggers in some cases the production of secondary small interfering RNAs (siRNAs), which in turn can silence other genes
in trans
. This alternative pathway depends on the length of the miRNA and the specific AGO in the effector complex. However, 22-nt miRNAs are sufficient, but not essential for this pathway. Using a combination of computational and experimental approaches, we show that transitivity can be triggered when the small RNA that is not retained in AGO is 22-nt long. Moreover, we demonstrate that asymmetrically positioned bulged bases in the miRNA:miRNA* duplex, regardless of miRNA or miRNA* length, are sufficient for the initiation of transitivity. We propose that the RNA-induced silencing complex reprogramming occurs during the early steps of miRNA loading, before the miRNA duplex is disassembled and the guide strand is selected.
Tension is required but not sufficient for focal adhesion maturation without a stress fiber template
Authors: Oakes Patrick W. , Beckham Yvonne , Stricker Jonathan , Gardel Margaret L.
Published: January 2012

Focal adhesion composition and size are modulated in a myosin II–dependent maturation process that controls adhesion, migration, and matrix remodeling. As myosin II activity drives stress fiber assembly and enhanced tension at adhesions simultaneously, the extent to which adhesion maturation is driven by tension or altered actin architecture is unknown. We show that perturbations to formin and α-actinin 1 activity selectively inhibited stress fiber assembly at adhesions but retained a contractile lamella that generated large tension on adhesions. Despite relatively unperturbed adhesion dynamics and force transmission, impaired stress fiber assembly impeded focal adhesion compositional maturation and fibronectin remodeling. Finally, we show that compositional maturation of focal adhesions could occur even when myosin II–dependent cellular tension was reduced by 80%. We propose that stress fiber assembly at the adhesion site serves as a structural template that facilitates adhesion maturation over a wide range of tensions. This work identifies the essential role of lamellar actin architecture in adhesion maturation.
The small G protein Arl1 directs the trans-Golgi–specific targeting of the Arf1 exchange factors BIG1 and BIG2
Authors: Christis Chantal , Munro Sean
Published: January 2012

The small G protein Arf1 regulates Golgi traffic and is activated by two related types of guanine nucleotide exchange factor (GEF). GBF1 acts at the cis-Golgi, whereas BIG1 and its close paralog BIG2 act at the trans-Golgi. Peripheral membrane proteins such as these GEFs are often recruited to membranes by small G proteins, but the basis for specific recruitment of Arf GEFs, and hence Arfs, to Golgi membranes is not understood. In this paper, we report a liposome-based affinity purification method to identify effectors for small G proteins of the Arf family. We validate this with the Drosophila melanogaster Arf1 orthologue (Arf79F) and the related class II Arf (Arf102F), which showed a similar pattern of effector binding. Applying the method to the Arf-like G protein Arl1, we found that it binds directly to Sec71, the Drosophila ortholog of BIG1 and BIG2, via an N-terminal region. We show that in mammalian cells, Arl1 is necessary for Golgi recruitment of BIG1 and BIG2 but not GBF1. Thus, Arl1 acts to direct a trans-Golgi–specific Arf1 GEF, and hence active Arf1, to the trans side of the Golgi.
Microbiota-induced IL-1β, but not IL-6, is critical for the development of steady-state TH17 cells in the intestine
Authors: Shaw Michael H. , Kamada Nobuhiko , Kim Yun-Gi , Núñez Gabriel
Published: January 2012

TH17 cells are a lineage of CD4+ T cells that are critical for host defense and autoimmunity by expressing the cytokines IL-17A, IL-17F, and IL-22. A feature of TH17 cells at steady state is their ubiquitous presence in the lamina propria of the small intestine. The induction of these steady-state intestinal TH17 (sTH17) cells is dependent on the presence of the microbiota. However, the signaling pathway linking the microbiota to the development of intestinal sTH17 cells remains unclear. In this study, we show that IL-1β, but not IL-6, is induced by the presence of the microbiota in intestinal macrophages and is required for the induction of sTH17 cells. In the absence of IL-1β–IL-1R or MyD88 signaling, there is a selective reduction in the frequency of intestinal sTH17 cells and impaired production of IL-17 and IL-22. Myeloid differentiation factor 88–deficient (MyD88−/−) and germ-free (GF) mice, but not IL-1R−/− mice, exhibit impairment in IL-1β induction. Microbiota-induced IL-1β acts directly on IL-1R–expressing T cells to drive the generation of sTH17 cells. Furthermore, administration of IL-1β into GF mice induces the development of retinoic acid receptor–related orphan receptor γt–expressing sTH17 cells in the small intestine, but not in the spleen. Thus, commensal-induced IL-1β production is a critical step for sTH17 differentiation in the intestine, which may have therapeutic implications for TH17-mediated pathologies.
Thermal degradation kinetics of poly {N-[(4-bromo- 3,5-difluorine)-phenyl]maleimide-co-styrene} in nitrogen
Authors: Li Yanxun , Xu Li , Yao Xinding , Luo Tingliang , Liu Guoji
Published: January 2012

The nonisothermal degradation kinetics of the copolymer poly{N-[(4-bromo-3,5-difluorine)phenyl]maleimide-co-styrene}, which was synthesized with N-[(4-bromo-3,5-difluorine)phenyl]maleimide and styrene, were studied by thermogravimetry/derivative thermogravimetry techniques. The kinetic parameters, including the activation energy and the pre-exponential factor of the copolymer degradation process, were calculated by the Kissinger and Flynn-Wall-Ozawa methods. The thermal degradation mechanism of the copolymer was also studied with the Satava-Sestak method. The results show that the activation energies were 165.97 kJ/mol with the Kissinger method and 169.04 kJ/mol with the Flynn-Wall-Ozawa method. The degradation of the copolymer followed a kinetic model of a nucleation and growth and the kinetic equation could be expressed asG(α) = [-ln(1-α)]1/2[whereG(α) is the integral function of conversion andαis the extent of conversion of the reactant decomposed at timet]. The reaction order was 1/2.
Structural analysis of TiO2and TiO2-Ag thin films and their antibacterial behaviors
Authors: Hsieh J H , Yu R B , Chang Y K , Li C
Published: January 2012

TiO2(rutile and anatase) thin films was first prepared using reactive sputtering, in an Ar+O2plasma. In the 2nd stage of the experiment, various amounts (3, 7, and 10 at. %) of Ag was doped into the rutile film in order to form TiO2-Ag thin films. These films were annealed for one hour in Ar atmosphere, at 300, 400, and 500 °C. The films' structures were then examined using X-ray diffractometry. FESEM (field-emission scaning electron microscopy) was used to investigate the surface emergence of Ag particles. As for the examination of optical band gaps and absorption of these films, UV-Vis-NIR photometer was used. The results show that, in as-deposited condition, the addition of Ag might disrupt the growth of crystalline structure and cause the formation of amorphous films. After annealing, it is found that the structure tends to become anatase phase which is a metastable phase between amorphous titanium oxide and rutile. More importantly, the absorption of the Ag-doped films would be enhanced in the visible-light range. Some of the enhancement is clearly due to plasmon resonance effect. The Ag-doped samples have shown some antibacterial effect in dark. When irradiated with light, the samples show a synergistic behavior combining the bactericidal effect of Ag ions and photocatalytic effect of TiO2.
Atrial dyssynchrony syndrome: an overlooked phenomenon and a potential cause of ‘diastolic’ heart failure
Authors: Eicher Jean‐Christophe , Laurent Gabriel , Mathé Anaëlle , Barthez Olivier , Bertaux Géraldine , Philip Jean‐Luc , Dorian Paul , Wolf Jean‐Eric
Published: January 2012

Aims

The purpose of the present study was too explore the role of interatrial dyssynchrony in heart failure with preserved ejection fraction (HFPEF).

Methods and results

For the case study we selected seven patients with severe HFPEF, with interatrial block on electrocardiogram (ECG), and a delayed and interrupted A wave on mitral Doppler. Echocardiographic left atrial (LA) volumes/functions, mitral E/A and E/e‘ ratios, mitral A wave duration/deceleration time, and interatrial mechanical delays (IAMDs) at tissue Doppler, were studied. We performed right heart catheterization, and an electrophysiological study (EPS) for the measurement of interatrial conduction delay (IACD) and left atrioventricular interval (LAVI). Mean IAMD was 106 ms. All the patients exhibited a restrictive mitral Doppler pattern, high E/A and E/e' ratios, and short A wave duration/deceleration time. Left atrial volume was increased, with severely depressed functions. Right heart catheterization showed severe post‐capillary pulmonary hypertension. The EPS showed an IACD of 170 ± 20 ms, with a short LAVI. Left atrial pacing through the coronary sinus reduced the IACD to 25 ± 15 ms. In the pilot study, 29 patients with HFPEF were compared with 27 age‐matched control patients. HFPEF patients had longer P waves, shorter A waves, and a longer IAMD than the controls. Prevalence of severe IAMD >60 ms was 59% in HFPEF and 0% in controls. In the HFPEF group, patients with an IAMD >60 ms had significantly shorter A waves and higher E/e' ratio.

Conclusion

Some HFPEF patients present with IACD, delayed LA systole, shortened LA emptying, decreased LA compliance, and increased filling pressures. Whether the condition of these patients could be improved by atrial resynchronization deserves further investigation.
Xenon Attenuates Hippocampal Long-term Potentiation by Diminishing Synaptic and Extrasynaptic N -methyl-D-aspartate Receptor Currents
Authors: Kratzer Stephan , Mattusch Corinna , Kochs Eberhard , Eder Matthias , Haseneder Rainer , Rammes Gerhard
Published: January 2012

Background

The memory-blocking properties of general anesthetics are of high clinical relevance and scientific interest. The inhalational anesthetic xenon antagonizes N-methyl-D-aspartate (NMDA) receptors. It is unknown if xenon affects long-term potentiation (LTP), a cellular correlate for memory formation. In hippocampal brain slices, the authors investigated in area CA1 whether xenon affects LTP, NMDA receptor-mediated neurotransmission, and intracellular calcium concentrations.

Methods

In sagittal murine hippocampal brain slices, the authors investigated the effects of xenon on LTP by recording excitatory postsynaptic field potentials. Using fluorometric calcium imaging, the authors tested the influence of xenon on calcium influx during high-frequency stimulation. In addition, using the patch-clamp technique, the xenon effect on synaptic and extrasynaptic NMDA receptors and L-type calcium channels was examined.

Results

In the absence of xenon, high-frequency stimulation reliably induced LTP and potentiated field potential slopes to (mean ± SEM) 127.2 ± 5.8% (P < 0.001). In the presence of xenon, high-frequency stimulation induced only a short-term potentiation, and field potentials returned to baseline level after 15-20 min (105.9 ± 2.9%; P = 0.090). NMDA receptor-mediated excitatory postsynaptic currents were reduced reversibly by xenon to 65.9 ± 9.4% (P = 0.007) of control. When extrasynaptic receptors were activated, xenon decreased NMDA currents to 58.2 ± 5.8% (P < 0.001). Xenon reduced the increase in intracellular calcium during high-frequency stimulation without affecting L-type calcium channels.

Conclusions

N-methyl-D-aspartate receptor activation is crucial for the induction of CA1 LTP. Thus, the depression of NMDA receptor-mediated neurotransmission presumably contributes to the blockade of LTP under xenon. Because LTP is assumed to be involved in learning and memory, its blockade might be a key mechanism for xenon's amnestic properties.
The Ubiquitin E3 Ligase LOSS OF GDU2 Is Required for GLUTAMINE DUMPER1-Induced Amino Acid Secretion in Arabidopsis
Authors: Pratelli Réjane , Guerra Damian D. , Yu Shi , Wogulis Mark , Kraft Edward , Frommer Wolf B. , Callis Judy , Pilot Guillaume
Published: January 2012

Amino acids serve as transport forms for organic nitrogen in the plant, and multiple transport steps are involved in cellular import and export. While the nature of the export mechanism is unknown, overexpression of GLUTAMINE  DUMPER1 (GDU1) in Arabidopsis (Arabidopsis thaliana) led to increased amino acid export. To gain insight into GDU1’s role, we searched for ethyl-methanesulfonate suppressor mutants and performed yeast-two-hybrid screens. Both methods uncovered the same gene, LOSS OF GDU2 (LOG2), which encodes a RING-type E3 ubiquitin ligase. The interaction between LOG2 and GDU1 was confirmed by glutathione S-transferase pull-down, in vitro ubiquitination, and in planta coimmunoprecipitation experiments. Confocal microscopy and subcellular fractionation indicated that LOG2 and GDU1 both localized to membranes and were enriched at the plasma membrane. LOG2 expression overlapped with GDU1 in the xylem and phloem tissues of Arabidopsis. The GDU1 protein encoded by the previously characterized intragenic suppressor mutant log1-1, with an arginine in place of a conserved glycine, failed to interact in the multiple assays, suggesting that the Gdu1D phenotype requires the interaction of GDU1 with LOG2. This hypothesis was supported by suppression of the Gdu1D phenotype after reduction of LOG2 expression using either artificial microRNAs or a LOG2 T-DNA insertion. Altogether, in accordance with the emerging bulk of data showing membrane protein regulation via ubiquitination, these data suggest that the interaction of GDU1 and the ubiquitin ligase LOG2 plays a significant role in the regulation of amino acid export from plant cells.
A Novel Method of Transgene Delivery into Triticale Plants Using the Agrobacterium Transferred DNA-Derived Nano-Complex
Authors: Ziemienowicz Alicja , Shim Youn-Seb , Matsuoka Aki , Eudes Francois , Kovalchuk Igor
Published: January 2012

Genetic transformation of monocotyledonous plants still presents a challenge for plant biologists and biotechnologists because monocots are difficult to transform with Agrobacterium tumefaciens, whereas other transgenesis methods, such as gold particle-mediated transformation, result in poor transgene expression because of integration of truncated DNA molecules. We developed a method of transgene delivery into monocots. This method relies on the use of an in vitro-prepared nano-complex consisting of transferred DNA, virulence protein D2, and recombination protein A delivered to triticale microspores with the help of a Tat2 cell-penetrating peptide. We showed that this approach allowed for single transgene copy integration events and prevented degradation of delivered DNA, thus leading to the integration of intact copies of the transgene into the genome of triticale plants. This resulted in transgene expression in all transgenic plants regenerated from microspores transfected with the full transferred DNA/protein complex. This approach can easily substitute the bombardment technique currently used for monocots and will be highly valuable for plant biology and biotechnology.
The decline of anti‐drug antibody titres after discontinuation of anti‐TNFs: implications for predicting re‐induction outcome in IBD
Authors: Ben‐Horin S. , Mazor Y. , Yanai H. , Ron Y. , Kopylov U. , Yavzori M. , Picard O. , Fudim E. , Maor Y. , Lahat A. , Coscas D. , Eliakim R. , Dotan I. , Chowers Y.
Published: January 2012

Background

Anti‐drug antibodies can be elicited by infliximab and adalimumab, but the rate of their decay after therapy is stopped is unknown.

Aim

To investigate the decline of anti‐drug antibody titre after anti‐TNF cessation, and to evaluate the clinical utility of anti‐drug antibody measurement before anti‐TNF re‐induction.

Methods

Inflammatory bowel disease (IBD) patients who stopped anti‐TNF therapy and had measurable anti‐drug antibodies were prospectively followed up by serial blood measurements of antibodies levels. The clinical outcome of a second cohort of patients who received re‐induction by infliximab or adalimumab after a drug holiday >4 months was determined vis‐à‐vis their anti‐drug antibodies status before re‐induction.

Results

The first cohort included 22 patients with anti‐drug antibodies who were prospectively followed up after cessation of anti‐TNF. Sixteen had antibodies‐to‐infliximab (ATI) and six had antibodies‐to‐adalimumab (ATA). ATI titres declined within 12 months to below detection levels in 13/16 infliximab‐treated patients, whereas ATA titres became undetectable in only 2/6 adalimumab‐treated patients (P = 0.04). The second cohort comprised 27 patients who resumed anti‐TNFs (24 infliximab, 3 adalimumab). Of these, 3/5 patients with measurable anti‐drug antibodies before re‐induction experienced severe hypersensitivity reaction and/or nonresponse mandating drug‐discontinuation, compared to 11/22 patients who were re‐induced without measurable anti‐drug antibodies (OR = 1.5, 95% CI 0.2–11, P = 0.7).

Conclusions

Antibodies to infliximab titres decline to undetectable levels within one year of cessation of infliximab in the majority of patients, whereas antibodies to adalimumab seem to persist longer after adalimumab discontinuation. Measuring antibodies to infliximab prior to infliximab re‐induction is probably of little clinical utility, especially if more than a 12‐month drug‐holiday has elapsed.
Intracranial hypotension headache after uncomplicated caudal epidural injection
Authors: Thomas R. , Thanthulage S.
Published: January 2012

A caudal epidural injection was performed on a middle‐aged woman for pain in her right foot. Although the procedure was uncomplicated and a good epidurogram was obtained, the patient went on to develop an orthostatic headache with generalised weakness and syncopal episodes that were treated successfully by epidural blood patching. We describe the aetiology, presentation and treatment of spontaneous intracranial hypotension and review the similarities with our patient’s clinical presentation. We hypothesise as to how our intervention may have resulted in a dural tear.
Cluster randomized trials of prescription medicines or prescribing policy: public and general practitioner opinions in Scotland
Authors: Mackenzie Isla S. , Wei Li , Paterson Kenneth R. , MacDonald Thomas M.
Published: January 2012

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

• Cluster randomized trials (randomized policy design studies) can be used to compare the safety and effectiveness of different interventions.

• Cluster randomized trials are relatively novel in the context of studying drug interventions.

• Using cluster randomized trials to investigate drug safety and effectiveness would require public and primary‐care practitioner co‐operation.

WHAT THIS STUDY ADDS

• The general public in Scotland is broadly supportive of the concept of cluster randomized trials (randomized policy design studies) to improve understanding of comparative effectiveness and safety of medicines within the National Health Service.

• There is a spread of opinion among general practitioners in Scotland regarding the acceptability of the concept of cluster randomized trials in the field of drug safety and effectiveness.

• Of the general public participants, 97% agreed that the National Health Service has a duty to determine the safety and effectiveness of the medicines its doctors prescribe.

AIMS To understand public and general practitioner (GP) opinion on the acceptability of randomized policy design (RPD) studies (cluster randomized trials) of prescription medicines in Scotland.

METHODS We surveyed public opinion on the concept of RPD studies in a sample of 1040 adults to determine acceptability and understand how people feel when changes are made to their medicines. We also surveyed GPs (n = 1034) about the concept of RPD studies as a tool for improving understanding of comparative effectiveness and safety of medicines in the ‘usual care’ setting.

RESULTS Thirty per cent of people would be happy to receive a letter about randomized policy changes to their therapy, 31% would not mind or had no opinion and 39% would be unhappy. This view was sensitive to the reason for change; effectiveness and safety reasons were most acceptable (96%) and cost saving least acceptable (39%). Only 19% thought randomized policy change was not an acceptable method of determining the best treatments. Eighty‐one per cent of respondents were willing for their medical data to be followed up to compare drug treatments (further 10% undecided). Participants reporting long‐term medical conditions and those reporting previous changes to drug therapy were more in favour of RPD studies than other participants.

Thirty‐three per cent (n = 341) of GPs responded to our survey. Of these, 45% were in favour of RPD studies, 19% were undecided and 36% not in favour.

CONCLUSIONS The public in Scotland is broadly supportive of the concept of randomized policy design studies of medicines, while there is a spread of opinion among GPs.
Inhibition of sphingosine kinase 1 suppresses proliferation of glioma cells under hypoxia by attenuating activity of extracellular signal‐regulated kinase
Authors: Zhang H. , Li W. , Sun S. , Yu S. , Zhang M. , Zou F.
Published: January 2012

Objectives:  Sphingosine kinase (SphK), which is regulated by hypoxia, catalyses phosphorylation of sphingosine to produce sphingosine‐1‐phosphate, which stimulates invasiveness of gliomas. However, whether SphK is involved in proliferation of glioma cells under hypoxic conditions is not clearly understood. In this study, we have investigated the role of SphK in of proliferation glioma cells under hypoxia.

Materials and methods:  Effects of small interfering RNA (siRNA) on SphKs, SKI (inhibitor of SphK) and U0126 (inhibitor of ERK) on proliferation of glioma cells under hypoxia were studied using CCK‐8 assay and flow cytometry. Protein expression profiles were evaluated by Western blot analysis.

Results:  SKI suppressed proliferation of glioma cells under hypoxia. Similarly, downregulation of SphKs by siRNA inhibited glioma cell proliferation, and the cell cycle was arrested in G2/M phase when SphK1 was inhibited. In addition, inhibition of SphK1 attenuated phosphorylation of ERK in hypoxic conditions. Furthermore, U0126 markedly inhibited cell population growth and arrested cells in G2/M as effectively as SKI. However, silencing SphK2 induced cell cycle arrest in the S phase and it showed little effect on hypoxia‐induced activation of ERK.

Conclusions:  SphK1 and SphK2 are involved in proliferation of glioma cells in hypoxic conditions through distinct signalling pathways. SphK1, but not SphK2, promotes cell population expansion in hypoxic conditions by activating ERK.
Specific subcutaneous immunotherapy with recombinant grass pollen allergens: first randomized dose‐ranging safety study
Authors: Klimek L. , Schendzielorz P. , Pinol R. , Pfaar O.
Published: January 2012

Background

Allergen‐specific immunotherapy (SIT) with native allergen extracts and allergoids has been performed successfully for decades. Preliminary studies revealed the use of recombinant allergen‐preparations as a promising option for SIT.

Objective

The present study was designed to investigate the dose‐ranging safety in SCIT with a mixture of five recombinant grass pollen allergens containing equimolar amounts of rPhl p 1, rPhl p2, rPhl p 5a, rPhl p 5b and rPhl p 6, adsorbed to aluminium hydroxide.

Methods

A randomized, double blind, placebo‐controlled, dose‐ranging safety study (EudraCT number 2007‐002808‐18) was performed in 50 patients with allergic rhinoconjunctivitis, with or without asthma. Patients were randomized to groups of 10 to receive maximum doses of 20, 40, 80 or 120 μg of total grass pollen recombinant protein or placebo.

The primary end‐point of this trial was the number of patients with at least one systemic reaction with possible, probable or definite relationship to the study medication determined at the end of the up‐dosing phase. Secondary end‐points included titrated intracutaneous test with natural six‐grass pollen extract, allergen‐specific conjunctival provocation test as well as IgG and IgE‐levels throughout the study.

Results

Eight of the 50 patients revealed systemic reactions grade 1 or 2 corresponding to the primary end‐point definition. No systemic reactions grade 3 or 4 occurred in any dosage group. The systemic reactions were well distributed among the active groups. Results of secondary end‐points imply that the study medication is effective and provokes immunological effects.

Conclusions and Clinical Relevance

The first DBPC SCIT‐DRF with a mixture of recombinant Phleum allergens (Phl p 1, 2, 5a, 5b, 6) in patients with rhinoconjunctivitis plus/minus asthma showed no major side effects in very high doses up to 120 μg.
Nutritional potential, bioaccessibility of minerals and antioxidant properties of niger (Guizotia abyssinicacass.) seed protein
Authors: Thatte Prachi , Jyothi Lakshmi A.
Published: January 2012

The investigation aimed at preparing protein isolate from niger seeds and determining its nutritional profile, functional properties and antioxidant potential. Niger seeds with 25.5% protein, 30% fat and 21.8% fibre were used for preparation of dehulled, defatted niger seed flour (DNF) and protein isolate (NPI). Protein content of DNF was 53.8% and NPI was 85.7%. Minerals, crude fiber and carbohydrate content reduced from DNF to NPI. In vitro protein digestibility, iron and zinc dialysability increased significantly from DNF to NPI with a corresponding decrease in fibre, tannin and phytate. Water and fat absorption capacity (FAC) was higher in DNF and foaming and emulsification index was better in NPI. Polyphenol content of NPI was higher than DNP. NPI exhibited significantly higher free radical scavenging ability and metal chelating ability, hydroxyl radical scavenging activity was comparable to DNP. Studies on organo‐leptic evaluation and utilisation of NPI as a protein source in food formulations are warranted.
Tensile and water vapour properties of calcium‐crosslinked alginate‐cashew tree gum films
Authors: Azeredo Henriette M. C. , Magalhães Ulysses S. , Oliveira Samira A. , Ribeiro Hálisson L. , Brito Edy S. , De Moura Márcia R.
Published: January 2012

In this study, sodium alginate films were blended with cashew tree gum (CTG) and immersed in CaCl2 solution. The influence of CTG concentration and immersion time in CaCl2 on tensile properties, water vapour permeability and water solubility (WS) of alginate films was evaluated. Glycerol‐plasticized alginate/CTG films were cast on glass plates, which were then immersed in a 2% CaCl2 solution to crosslink alginate. CTG concentration in the film solution and immersion time in CaCl2 bath were varied according to a central composite design. Tensile strength, Young′s modulus, WS and water vapour barrier of the films were favoured by higher immersion times in CaCl2 and lower CTG concentrations. The negative CTG effects on such properties have been attributed to competition between the polysaccharides for interactions with calcium ions, reducing crosslinking density and loosening the film structure. On the other hand, this loosening effect resulted in higher film flexibility at higher CTG concentrations.
Imported fire ants near the edge of their range: disturbance and moisture determine prevalence and impact of an invasive social insect
Authors: LeBrun Edward G. , Plowes Robert M. , Gilbert Lawrence E.
Published: January 2012

1. Habitat disturbance and species invasions interact in natural systems, making it difficult to isolate the primary cause of ecosystem degradation. A general understanding requires case studies of how disturbance and invasion interact across a variety of ecosystem – invasive species combinations.

2. Dramatic losses in ant diversity followed the invasion of central Texas by red imported fire ants (Solenopsis invicta). However, recent manipulative studies in Florida revealed no effect on ant diversity following the removal of S. invicta from a disturbed pasture habitat, but moderate loss of diversity associated with their introduction into undisturbed habitat and no invasion occurred without disturbance. Thus, the importance of S. invicta in driving diversity loss and its ability to invade undisturbed systems is unresolved.

3. We examine the distribution and abundance of a large monogyne S. invicta population and its association with the co‐occurring ant assemblage at a site in south Texas close to the aridity tolerance limit of S. invicta.

4. We document that moisture modulates S. invicta densities. Further, soil disturbing habitat manipulations greatly increase S. invicta population densities. However, S. invicta penetrates all habitats regardless of soil disturbance history. In contrast, controlled burns depress S. invicta densities.

5. In habitats where S. invicta is prevalent, it completely replaces native fire ants. However, S. invicta impacts native ants as a whole less strongly. Intriguingly, native ants responded distinctly to S. invicta in different environments. In wet, undisturbed environments, high S. invicta abundance disrupts the spatial structure of the ant assemblage by increasing clumping and is associated with reduced species density, while in dry‐disturbed habitats, sites with high S. invicta abundance possess high numbers of native species. Analyses of co‐occurrence indicate that reduced species density in wet‐undisturbed sites arises from negative species interactions between native ants and S. invicta. However, these same data suggest that the high native species density of abundant S. invicta sites in dry‐disturbed environments does not result from facilitation.

6. Monogyne S. invicta populations play different roles in different environments, driving ant diversity loss in some, but being largely symptomatic of habitat disturbance in others.
Using TPACK as a framework to understand teacher candidates' technology integration decisions
Authors: Graham C.R. , Borup J. , Smith N.B.
Published: January 2012

This research uses the technological pedagogical and content knowledge (TPACK) framework as a lens for understanding how teacher candidates make decisions about the use of information and communication technology in their teaching. Pre‐ and post‐treatment assessments required elementary teacher candidates at Brigham Young University to articulate how and why they would integrate technology in three content teaching design tasks. Researchers identified themes from student rationales that mapped to the TPACK constructs. Rationales simultaneously supported subcategories of knowledge that could be helpful to other researchers trying to understand and measure TPACK. The research showed significant student growth in the use of rationales grounded in content‐specific knowledge and general pedagogical knowledge, while rationales related to general technological knowledge remained constant.
Influence of landscape and social interactions on transmission of disease in a social cervid
Authors: VANDER WAL ERIC , PAQUET PAUL C. , ANDRÉS JOSÉ A.
Published: January 2012

The mechanisms of pathogen transmission are often social behaviours. These occur at local scales and are affected by landscape‐scale population structure. Host populations frequently exist in patchy and isolated environments that create a continuum of genetic and social familiarity. Such variability has an important multispatial effect on pathogen spread. We assessed elk dispersal (i.e. likelihood of interdeme pathogen transmission) through spatially explicit genetic analyses. At a landscape scale, the elk population was composed of one cluster within a southeast‐to‐northwest cline spanning three spatially discrete subpopulations of elk across two protected areas in Manitoba (Canada). Genetic data are consistent with spatial variability in apparent prevalence of bovine tuberculosis (TB) in elk. Given the existing population structure, between‐subpopulation spread of disease because of elk dispersal is unlikely. Furthermore, to better understand the risk of spread and distribution of the TB, we used a combination of close‐contact logging biotelemetry and genetic data, which highlights how social intercourse may affect pathogen transmission. Our results indicate that close‐contact interaction rate and duration did not covary with genetic relatedness. Thus, direct elk‐to‐elk transmission of disease is unlikely to be constrained to related individuals. That social intercourse in elk is not limited to familial groups provides some evidence pathogen transmission may be density‐dependent. We show that the combination of landscape‐scale genetics, relatedness and local‐scale social behaviours is a promising approach to understand and predict landscape‐level pathogen transmission within our system and within all social ungulate systems affected by transmissible diseases.
Involvement of TatD nuclease during programmed cell death in the protozoan parasite Trypanosoma brucei
Authors: Gannavaram Sreenivas , Debrabant Alain
Published: January 2012

In this report, we describe the involvement of TatD nuclease during programmed cell death (PCD) in the human protozoan parasite Trypanosoma brucei. T. brucei TatD nuclease showed intrinsic DNase activity, was localized in the cytoplasm and translocated to the nucleus when cells were treated with inducers previously demonstrated to cause PCD in T. brucei. Overexpression of TatD nuclease resulted in elevated PCD and conversely, loss of TatD expression by RNAi conferred significant resistance to the induction of PCD in T. brucei. Co‐immunoprecipitation studies revealed that TatD nuclease interacts with endonucleaseG suggesting that these two nucleases could form a DNA degradation complex in the nucleus. Together, biochemical activity, RNAi and subcellular localization results demonstrate the role of TatD nuclease activity in DNA degradation during PCD in these evolutionarily ancient eukaryotic organisms. Further, in conjunction with endonucleaseG, TatD may represent a critical nuclease in a caspase‐independent PCD pathway in trypanosomatid parasites since caspases have not been identified in these organisms.
GDNF‐treated acellular nerve graft promotes motoneuron axon regeneration after implantation into cervical root avulsed spinal cord
Authors: Chu T‐H. , Wang L. , Guo A. , Chan V. W‐K. , Wong C. W‐M. , Wu W.
Published: January 2012

T‐H. Chu, L. Wang, A. Guo, V. W‐K. Chan, C. W‐M. Wong and W. Wu (2012) Neuropathology and Applied Neurobiology38, 681–695

GDNF‐treated acellular nerve graft promotes motoneuron axon regeneration after implantation into cervical root avulsed spinal cord

It is well known that glial cell line‐derived neurotrophic factor (GDNF) is a potent neurotrophic factor for motoneurons. We have previously shown that it greatly enhanced motoneuron survival and axon regeneration after implantation of peripheral nerve graft following spinal root avulsion. Aims: In the current study, we explore whether injection of GDNF promotes axon regeneration in decellularized nerve induced by repeated freeze‐thaw cycles. Methods: We injected saline or GDNF into the decellularized nerve after root avulsion in adult Sprague–Dawley rats and assessed motoneuron axon regeneration and Schwann cell migration by retrograde labelling and immunohistochemistry. Results: We found that no axons were present in saline‐treated acellular nerve whereas Schwann cells migrated into GDNF‐treated acellular nerve grafts. We also found that Schwann cells migrated into the nerve grafts as early as 4 days after implantation, coinciding with the first appearance of regenerating axons in the grafts. Application of GDNF outside the graft did not induce Schwann cell infiltration nor axon regeneration into the graft. Application of pleiotrophin, a trophic factor which promotes axon regeneration but not Schwann cell migration, did not promote axon infiltration into acellular nerve graft. Conclusions: We conclude that GDNF induced Schwann cell migration and axon regeneration into the acellular nerve graft. Our findings can be of potential clinical value to develop acellular nerve grafting for use in spinal root avulsion injuries.
Magnetotelluric image linked to surface geology across the Cape Fold Belt, South Africa
Authors: Weckmann Ute , Ritter Oliver , Chen Xiaoming , Tietze Kristina , de Wit Maarten
Published: January 2012

Terra Nova, 24, 207–212, 2012

The subsurface structure of the Cape Fold Belt (CFB) that traverses southern Africa remains largely unknown because it lacks deep‐penetrating, high‐resolution geophysics. This hampers studies from local‐scale exploration for important resources such as water, to continental‐scale modelling, such as Gondwana reconstructions. Our Magnetotelluric (MT) soundings across the CFB provide a high‐resolution crustal‐scale electrical conductivity image. Inversion models of these data correlate well with surface geology, and resolve deep resistive roots of the CFB’s regional Palaeozoic quartzite ridges (Swartberg and Outeniqua Mountains) and thin tectonic wedges of Proterozoic rocks of higher resistivity (Kango and Kaaimans Inliers), separated by 2–3 km of Cretaceous sediments in asymmetric intermontaine basins. One of these basins, the Oudtshoorn Basin, is flanked by a listric normal fault rooted in an upper crustal detachment zone, and is underlain by a massive conductivity anomaly that is likely to be a major saline water reservoir.
Fructokinase is required for carbon partitioning to cellulose in aspen wood
Authors: Roach Melissa , Gerber Lorenz , Sandquist David , Gorzsás András , Hedenström Mattias , Kumar Manoj , Steinhauser Marie Caroline , Feil Regina , Daniel Geoffrey , Stitt Mark , Sundberg Björn , Niittylä Totte
Published: January 2012

Sucrose is the main transported form of carbon in several plant species, including Populus species. Sucrose metabolism in developing wood has therefore a central role in carbon partitioning to stem biomass. Half of the sucrose‐derived carbon is in the form of fructose, but metabolism of fructose has received little attention as a factor in carbon partitioning to walls of wood cells. We show that RNAi‐mediated reduction of FRK2 activity in developing wood of hybrid aspen (Populus tremula × tremuloides) led to the accumulation of soluble neutral sugars and a decrease in hexose phosphates and UDP‐glucose, indicating that carbon flux to cell‐wall polysaccharide precursors is decreased. Reduced FRK2 activity also led to thinner fiber cell walls with a reduction in the proportion of cellulose. No pleiotropic effects on stem height or diameter were observed. The results establish a central role for FRK2 activity in carbon flux to wood cellulose.
46, XY gonadal dysgenesis: new SRY point mutation in two siblings with paternal germ line mosaicism
Authors: Stoppa‐Vaucher S , Ayabe T , Paquette J , Patey N , Francoeur D , Vuissoz J‐M , Deladoëy J , Samuels ME , Ogata T , Deal CL
Published: January 2012

Stoppa‐Vaucher S, Ayabe T, Paquette J, Patey N, Francoeur D, Vuissoz J‐M, Deladoëy J, Samuels ME, Ogata T, Deal CL. 46, XY gonadal dysgenesis: new SRY point mutation in two siblings with paternal germ line mosaicism.

Familial recurrence risks are poorly understood in cases of de novo mutations. In the event of parental germ line mosaicism, recurrence risks can be higher than generally appreciated, with implications for genetic counseling and clinical practice. In the course of treating a female with pubertal delay and hypergonadotropic hypogonadism, we identified a new missense mutation in the SRY gene, leading to somatic feminization of this karyotypically normal XY individual. We tested a younger sister despite a normal onset of puberty, who also possessed an XY karyotype and the same SRY mutation. Imaging studies in the sister revealed an ovarian tumor, which was removed. DNA from the father's blood possessed the wild type SRY sequence, and paternity testing was consistent with the given family structure. A brother was 46, XY with a wild type SRY sequence strongly suggesting paternal Y‐chromosome germline mosaicism for the mutation. In disorders of sexual development (DSDs), early diagnosis is critical for optimal psychological development of the affected patients. In this case, preventive karyotypic screening allowed early diagnosis of a gonadal tumor in the sibling prior to the age of normal puberty. Our results suggest that cytological or molecular diagnosis should be applied for siblings of an affected DSD individual.
Prolonged attenuation of acetylcholine‐induced phosphorylation of extracellular signal‐regulated kinase 1/2 following sevoflurane exposure
Authors: WIKLUND A. , GUSTAVSSON D. , EBBERYD A. , SUNDMAN E. , SCHULTE G. , JONSSON FAGERLUND M. , ERIKSSON L. I.
Published: January 2012

Background

Volatile anaesthetics are known to affect cholinergic receptors. Perturbation of cholinergic signalling can cause cognitive deficits. In this study, we wanted to evaluate acetylcholine‐induced intracellular signalling following sevoflurane exposure.

Methods

Pheochromocytoma12 PC12 cells were exposed to 4.6% sevoflurane for 2 h. Subsequently, Western blotting was used to measure acetylcholine‐induced phosphorylation of extracellular signal‐regulated kinase 1/2 (ERK) 1/2 and basal Protein kinase B (AKT) phosphorylation.

Results

After exposure, acetylcholine‐induced ERK 1/2 phosphorylation was reduced to 58 ± 8% [95% confidence interval (CI): 38–77%, P = 0.003] compared with non‐exposed controls. At 30 min after the end of sevoflurane administration [at 0.7% sevoflurane (0.102 mM)], ERK 1/2 phosphorylation remained reduced to 57 ± 7% (95% CI: 39–74%, P = 0.001) and was at 120 min [0.02% (0.003 mM] still reduced to 63 ± 10% (95% CI: 37–88%, P = 0.01), compared with control. At 360 min after exposure, acetylcholine‐induced ERK 1/2 phosphorylation had recovered to 98 ± 16% (95% CI: 45–152%, P = 0.98) compared with control. In contrast, immediately after sevoflurane exposure, basal AKT phosphorylation was increased by 228 ± 37% (95% CI: 133–324%, P = 0.02) but had returned to control levels at 30 min after exposure, 172 ± 67% (95% CI: 0–356%, P = 0.34).

Conclusion

Sevoflurane exposure has differential effects on different intracellular signalling pathways. On one hand, we observed a prolonged attenuation of acetylcholine‐induced ERK 1/2 phosphorylation that persisted even when sevoflurane concentrations close to detection level. On the other hand, basal AKT phosphorylation was increased twofold during sevoflurane exposure, with a rapid return to baseline levels after exposure. We speculate that the effects on acetylcholine‐induced intracellular signalling observed in our in vitro model could be of relevance also for cholinergic signalling in vivo following sevoflurane exposure.
Dynamic variables of fluid responsiveness during pneumoperitoneum and laparoscopic surgery
Authors: HØISETH L. Ø. , HOFF I. E. , MYRE K. , LANDSVERK S. A. , KIRKEBØEN K. A.
Published: January 2012

Background

Few data exist on dynamic variables predicting fluid responsiveness during laparoscopic surgery. The aim of this study was to explore the effects of laparoscopy on four dynamic variables: respiratory variations in pulse pressure (ΔPP), stroke volume variation by Vigileo/FloTrac (SVV
Vigileo), pleth variability index (PVI) and respiratory variations in pulse oximetry plethysmography waveform amplitude (ΔPOP), and their relation to fluid challenges during laparoscopic surgery.

Methods

ΔPP, SVV
Vigileo, PVI and ΔPOP were studied in 20 adult patients before and during pneumoperitoneum (10–12 mmHg). During ongoing laparoscopic surgery, relations between the dynamic variables and changes in stroke volume oesophageal Doppler, (SVOD) after fluid challenges (250 ml colloid) were evaluated.

Results

Pneumoperitoneum changed the dynamic variables as follows {mean [95% confidence interval (CI)]}: ΔPP 0.5 (−1.3, 2.3)%, P = 0.53; SVV
Vigileo 0.6 (−1.3, 2.5)%, P = 0.52; PVI 2.9 (0.4, 5.3)%, P = 0.025. For ΔPOP, median difference (95% CI) was 2.5 (−0.15, 6.7)%, P = 0.058. During laparoscopic surgery, areas under receiver operating characteristics curves (95% CI) were ΔPP 0.53 (0.31–0.75), SVV
Vigileo 0.74 (0.51–0.90), PVI 0.61 (0.38–0.81), ΔPOP 0.63 (0.40–0.82). Correlation coefficients (P‐values) between changes in dynamic variables and changes in SVOD were ΔPP r = −0.65, P = 0.009; SVV
Vigileo r = −0.73, P = 0.002; PVI r = −0.22, P = 0.44; ΔPOP r = −0.32, P = 0.24.

Conclusion

ΔPP and SVV
Vigileo did not change as pneumoperitoneum was established, whereas PVI increased and ΔPOP tended to increase. All four dynamic variables predicted fluid responsiveness relatively poor during ongoing laparoscopic surgery. ΔPP and SVV
Vigileo tracked changes in stroke volume induced by fluid challenges during ongoing laparascopic surgery, whereas ΔPOP and PVI did not.
Prescriptions analysis by clinical pharmacists in the post‐operative period: a 4‐year prospective study
Authors: CHARPIAT B. , GOUTELLE S. , SCHOEFFLER M. , AUBRUN F. , VIALE J.‐P. , DUCERF C. , LEBOUCHER G. , ALLENET B.
Published: January 2012

Background

Clinical pharmacists can help prevent medication errors. However, data are scarce on their role in preventing medication prescription errors in the post‐operative period, a high‐risk period, as at least two prescribers can intervene, the surgeon and the anesthetist. We aimed to describe and quantify clinical pharmacist' intervention (PIs) during validation of drug prescriptions on a computerized physician order entry system in a post‐surgical and post‐transplantation ward. We illustrate these interventions, focusing on one clearly identified recurrent problem.

Methods

In a prospective study lasting 4 years, we recorded drug‐related problems (DRPs) detected by pharmacists and whether the physician accepted the PI when prescription modification was suggested.

Results

Among 7005 orders, 1975 DRPs were detected. The frequency of PIs remained constant throughout the study period, with 921 PIs (47%) accepted, 383 (19%) refused and 671 (34%) not assessable. The most frequent DRP concerned improper administration mode (26%), drug interactions (21%) and overdosage (20%). These resulted in a change in the method of administration (25%), dose adjustment (24%) and drug discontinuation (23%) with 307 drugs being concerned by at least one PI. Paracetamol was involved in 26% of overdosage PIs. Erythromycin as prokinetic agent, presented a recurrent risk of potentially severe drug–drug interactions especially with other QT interval‐prolonging drugs. Following an educational seminar targeting this problem, the rate of acceptation of PI concerning this DRP increased.

Conclusion

Pharmacists detected many prescription errors that may have clinical implications and could be the basis for educational measures.