Bentho-planktonic evidence from the Austrian Alps for a decline in sea-surface carbonate production at the end of the Triassic

A high-resolution micropalaeontological study, combined with geochemical and sedimentological analyses was performed on the Tiefengraben, Schlossgraben and Eiberg sections (Austrian Alps) in order to characterize sea-surface carbonate production during the end-Triassic crisis. At the end-Rhaetian, the dominant calcareous nannofossil Prinsiosphaera triassica shows a decrease in abundance and size and this is correlated with a increase in delta O-18 and a gradual decline in delta C-13(carb) values. Simultaneously, benthic foraminiferal assemblages show a decrease in diversity and abundance of calcareous taxa and a dominance of infaunal agglutinated taxa. The smaller size of calcareous nannofossils disturbed the vertical export balance of the biological carbon pump towards the sea-bottom, resulting in changes in feeding strategies within the benthic foraminiferal assemblages from deposit feeders to detritus feeders and bacterial scavengers. These micropalaeontological data combined with geochemical proxies suggest that changes in seawater chemistry and/or cooling episodes might have occurred in the latest Triassic, leading to a marked decrease of carbonate production. This in turn culminated in the quasi-absence of calcareous nannofossils and benthic foraminifers in the latest Triassic. The aftermath (latest Triassic earliest Jurassic) was characterised by abundance peaks of ``disaster'' epifaunal agglutinated foraminifera Trochammina on the sea-floor. Central Atlantic Magmatic Province (CAMP) paroxysmal activity, superimposed on a major worldwide regressive phase, is assumed to be responsible for a deterioration in marine palaeoenvironments. CAMP sulfuric emissions might have been the trigger for cooling episodes and seawater acidification leading to disturbance of the surface carbonate production at the very end-Triassic.

Adjuvant requirement for successful immunization with recombinant derivatives of Plasmodium vivax merozoite surface protein-1 delivered via the intranasal route

Recently, we generated two bacterial recombinant proteins expressing 89 amino acids of the C-terminal domain of the Plasmodium vivax merozoite surface protein-1 and the hexa-histidine tag (His6MSP1(19)). One of these recombinant proteins contained also the amino acid sequence of the universal pan allelic T-cell epitope (His6MSP1(19)-PADRE). In the present study, we evaluated the immunogenic properties of these antigens when administered via the intra-nasal route in the presence of distinct adjuvant formulations. We found that C57BL/6 mice immunized with either recombinant proteins in the presence of the adjuvants cholera toxin (CT) or the Escherichia coli heat labile toxin (LT) developed high and long lasting titers of specific serum antibodies. The induced immune responses reached maximum levels after three immunizing doses with a prevailing IgG1 subclass response. In contrast, mice immunized by intranasal route with His6MSP1(19)-PADRE in the presence of the synthetic oligonucleotides adjuvant CpG ODN 1826 developed lower antibody titers but when combined to CT, CpG addition resulted in enhanced IgG responses characterized by lower IgG1 levels. Considering the limitations of antigens formulations that can be used in humans, mucosal adjuvants can be a reliable alternative for the development of new strategies of immunization using recombinant proteins of P. vivax.

Merozoite surface protein 2 allelic variation influences the specific antibody response during acute malaria in individuals from a Brazilian endemic area

The antibody response to Plasmodium falciparum parasites of naturally infected population is critical to elucidate the role of polymorphic alleles in malaria. Thus, we evaluated the impact of antigenic diversity of repetitive and family dimorphic domains of the merozoite surface protein 2 (MSP-2) on immune response of 96 individuals living in Peixoto de Azevedo (MT-Brazil), by ELISA using recombinant MSP-2 proteins. The majority of these individuals were carrying FC27-type infections. IgG antibody responses were predominantly directed to FC27 parasites and were correlated to the extension of polymorphism presented by each MSP-2 region. This finding demonstrated the impact of the genetic polymorphism on antibody response and therefore, its importance on malaria vaccine efficacy.

Identification of a novel 45-kDa cell surface molecule involved in activation of the human Jurkat T cell line.

This report describes a surface molecule, Tp45, which appears to be involved in interleukin 2 production and Ca2+ mobilization by Jurkat cells. The Tp45 molecule was identified by a monoclonal antibody, MX13, on the surface of either T3/TCR+ or T3/TCR- human T cell lines. Biochemical data showed that mAb MX13 precipitated a single polypeptide chain of 45 kDa both under reduced and nonreduced conditions from lysates of 125I-surface-labeled cells. Sequential immunodepletion experiments using lysates of 125I-labeled T3/TCR+ cells showed that Tp45 was distinct from the alpha chain of the TCR complex. However, incubation of such cells with either anti-T3 or anti-TCR monoclonal antibody induced complete modulation of both the T3/TCR complex and Tp45. Conversely, complete modulation of both Tp45 and the T3/TCR complex was observed after incubation with anti-Tp45 antibody. Functional studies showed that anti-Tp45 antibody induced high levels of interleukin 2 production in Jurkat cells. In addition, incubation of these cells with the antibody resulted in Ca2+ mobilization from internal stores. Anti-Tp45 antibody reacted with 3-19% peripheral blood (E-rosette-positive) T cells in individual donors. The magnitude of the proliferative response elicited by anti-Tp45 antibody for peripheral blood T cells was lower than that induced by an anti-T3 antibody. This observation is compatible with the idea that only a subpopulation of T cells is reactive with anti-Tp45. Multicolor flow cytometry analysis showed that the Tp45+ cells belong preferentially to the T8 subset.

A novel neutrophil elastase inhibitor prevents elastase activation and surface cleavage of the epithelial sodium channel expressed in Xenopus laevis oocytes.

The amiloride-sensitive epithelial sodium channel (ENaC) constitutes a limiting step in sodium reabsorption across distal airway epithelium and controlling mucociliary clearance. ENaC is activated by serine proteases secreted in the extracellular milieu. In cystic fibrosis lungs, high concentrations of secreted neutrophil elastase (NE) are observed. hNE could activate ENaC and contribute to further decreased mucociliary clearance. The aims of this study were (i) to test the ability of an engineered human neutrophil elastase inhibitor (EPI-hNE4) to specifically inhibit the elastase activation of ENaC-mediated amiloride-sensitive currents (I(Na)) and (ii) to examine the effect of elastase on cell surface expression of ENaC and its cleavage pattern (exogenous proteolysis). Oocytes were exposed to hNE (10-100 microg/ml) and/or trypsin (10 microg/ml) for 2-5 min in the presence or absence of EPI-hNE4 (0.7 microm). hNE activated I(Na) 3.6-fold (p < 0.001) relative to non-treated hENaC-injected oocytes. EPI-hNE4 fully inhibited hNE-activated I(Na) but had no effect on trypsin- or prostasin-activated I(Na). The co-activation of I(Na) by hNE and trypsin was not additive. Biotinylation experiments revealed that cell surface gamma ENaC (but not alpha or beta ENaC) exposed to hNE for 2 min was cleaved (as a 67-kDa fragment) and correlated with increased I(Na). The elastase-induced exogenous proteolysis pattern is distinct from the endogenous proteolysis pattern induced upon preferential assembly, suggesting a causal relationship between gamma ENaC cleavage and ENaC activation, taking place at the plasma membrane.

Naturally acquired antibodies to merozoite surface protein (MSP)-1(19) and cumulative exposure to Plasmodium falciparum and Plasmodium vivax in remote populations of the Amazon Basin of Brazil

To infer recent patterns of malaria transmission, we measured naturally acquired IgG antibodies to the conserved 19-kDa C-terminal region of the merozoite surface protein (MSP)-1 of both Plasmodium vivax (PvMSP-1(19)) and Plasmodium falciparum (PfMSP-1(19)) in remote malaria-exposed populations of the Amazon Basin. Community-based cross-sectional surveys were carried out between 2002 and 2003 in subjects of all age groups living along the margins of the Unini and Jaú rivers, Northwestern Brazil. We found high prevalence rates of IgG antibodies to PvMSP-1(19) (64.0 - 69.6%) and PfMSP-1(19) (51.6 - 52.0%), with significant differences in the proportion of subjects with antibodies to PvMSP-1(19) according to age, place of residence and habitual involvement in high-risk activities, defining some groups of highly exposed people who might be preferential targets of malaria control measures. In contrast, no risk factor other than age was significantly associated with seropositivity to PfMSP-1(19). Only 14.1% and 19.3% of the subjects tested for antibodies to PvMSP-1(19) and PfMSP-1(19) in consecutive surveys (142 - 203 days apart) seroconverted or had a three fold or higher increase in the levels of antibodies to these antigens. We discuss the extent to which serological data correlated with the classical malariometric indices and morbidity indicators measured in the studied population at the time of the seroprevalence surveys and highlight some limitations of serological data for epidemiological inference.

GLUT2 surface expression and intracellular transport via the constitutive pathway in pancreatic beta cells and insulinoma: evidence for a block in trans-Golgi network exit by brefeldin A.

The biosynthesis, intracellular transport, and surface expression of the beta cell glucose transporter GLUT2 was investigated in isolated islets and insulinoma cells. Using a trypsin sensitivity assay to measure cell surface expression, we determined that: (a) greater than 95% of GLUT2 was expressed on the plasma membrane; (b) GLUT2 did not recycle in intracellular vesicles; and (c) after trypsin treatment, reexpression of the intact transporter occurred with a t1/2 of approximately 7 h. Kinetics of intracellular transport of GLUT2 was investigated in pulse-labeling experiments combined with glycosidase treatment and the trypsin sensitivity assay. We determined that transport from the endoplasmic reticulum to the trans-Golgi network (TGN) occurred with a t1/2 of 15 min and that transport from the TGN to the plasma membrane required a similar half-time. When added at the start of a pulse-labeling experiment, brefeldin A prevented exit of GLUT2 from the endoplasmic reticulum. When the transporter was first accumulated in the TGN during a 15-min period of chase, but not following a low temperature (22 degrees C) incubation, addition of brefeldin A (BFA) prevented subsequent surface expression of the transporter. This indicated that brefeldin A prevented GLUT2 exit from the TGN by acting at a site proximal to the 22 degrees C block. Together, these data demonstrate that GLUT2 surface expression in beta cells is via the constitutive pathway, that transport can be blocked by BFA at two distinct steps and that once on the surface, GLUT2 does not recycle in intracellular vesicles.

Free-breathing 3 T magnetic resonance t(2)-mapping of the heart.

OBJECTIVES: This study sought to establish an accurate and reproducible T(2)-mapping cardiac magnetic resonance (CMR) methodology at 3 T and to evaluate it in healthy volunteers and patients with myocardial infarct. BACKGROUND: Myocardial edema affects the T(2) relaxation time on CMR. Therefore, T(2)-mapping has been established to characterize edema at 1.5 T. A 3 T implementation designed for longitudinal studies and aimed at guiding and monitoring therapy remains to be implemented, thoroughly characterized, and evaluated in vivo. METHODS: A free-breathing navigator-gated radial CMR pulse sequence with an adiabatic T(2) preparation module and an empirical fitting equation for T(2) quantification was optimized using numerical simulations and was validated at 3 T in a phantom study. Its reproducibility for myocardial T(2) quantification was then ascertained in healthy volunteers and improved using an external reference phantom with known T(2). In a small cohort of patients with established myocardial infarction, the local T(2) value and extent of the edematous region were determined and compared with conventional T(2)-weighted CMR and x-ray coronary angiography, where available. RESULTS: The numerical simulations and phantom study demonstrated that the empirical fitting equation is significantly more accurate for T(2) quantification than that for the more conventional exponential decay. The volunteer study consistently demonstrated a reproducibility error as low as 2 ± 1% using the external reference phantom and an average myocardial T(2) of 38.5 ± 4.5 ms. Intraobserver and interobserver variability in the volunteers were -0.04 ± 0.89 ms (p = 0.86) and -0.23 ± 0.91 ms (p = 0.87), respectively. In the infarction patients, the T(2) in edema was 62.4 ± 9.2 ms and was consistent with the x-ray angiographic findings. Simultaneously, the extent of the edematous region by T(2)-mapping correlated well with that from the T(2)-weighted images (r = 0.91). CONCLUSIONS: The new, well-characterized 3 T methodology enables robust and accurate cardiac T(2)-mapping at 3 T with high spatial resolution, while the addition of a reference phantom improves reproducibility. This technique may be well suited for longitudinal studies in patients with suspected or established heart disease.

Kinetoplastid membrane protein-11 is present in promastigotes and amastigotes of Leishmania amazonensis and its surface expression increases during metacyclogenesis

Kinetoplastid membrane protein-11 (KMP-11), a protein present in all kinetoplastid protozoa, is considered a potential candidate for a leishmaniasis vaccine. A suitable leishmaniasis vaccine candidate molecule must be expressed in amastigotes, the infective stage for mammals. However, the expression of KMP-11 in Leishmania amastigotes has been a subject of controversy. We evaluated the expression of this molecule in logarithmic and stationary growth phase promastigotes, as well as in amastigotes, of Leishmania amazonensis by immunoblotting, flow cytometry and immunocytochemistry, using a monoclonal antibody against KMP-11. We found that KMP-11 is present in promastigotes and amastigotes. In both stages, the protein was found in association with membrane structures (at the cell surface, flagellar pocket and intracellular vesicles). More importantly, its surface expression is higher in amastigotes than in promastigotes and increases during metacyclogenesis. The increased expression of KMP-11 in metacyclic promastigotes, and especially in amastigotes, indicates a role for this molecule in the parasite relationship with the mammalian host. The presence of this molecule in amastigotes is consistent with the previously demonstrated immunoprotective capacity of vaccine prototypes based on the KMP-11-coding gene and the presence of humoral and cellular immune responses to KMP-11 in Leishmania-infected humans and animals.

Surface registration from range image fusion

The registration of full 3-D models is an important task in computer vision. Range finders only reconstruct a partial view of the object. Many authors have proposed several techniques to register 3D surfaces from multiple views in which there are basically two aspects to consider. First, poor registration in which some sort of correspondences are established. Second, accurate registration in order to obtain a better solution. A survey of the most common techniques is presented and includes experimental results of some of them

Regulation of the intracellular distribution, cell surface expression, and protein levels of AMPA receptor GluR2 subunits by the monocarboxylate transporter MCT2 in neuronal cells.

The neuronal monocarboxylate transporter, MCT2, is not only an energy substrate carrier but it is also purported to be a binding partner for the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor GluR2 subunit. To unravel a putative role of MCT2 in the regulation of GluR2 subcellular distribution, Neuro2A cells and primary cultures of mouse cortical neurons were co-transfected with plasmids containing sequences to express the fluorescent proteins mStrawberry (mStb)-fused MCT2 and Venus-fused GluR2. Subsequently, their subcellular distribution was visualized by fluorescence microscopy. GluR2 was led to form perinuclear and dendritic clusters together with MCT2 when co-transfected in Neuro2A cells or in neurons, following the original distribution of MCT2. MCT2 co-transfection had no effect on the intracellular distribution of several other post-synaptic proteins, although it partially affected the intracellular distribution of GluR1 similarly to GluR2. Both cell surface and total protein expression levels of GluR2 were significantly reduced by co-expression with MCT2. Finally, partial perinuclear and dendritic co-localization between MCT2 and Rab8, a member of the small GTPase family involved in membrane trafficking of AMPA receptors, was also observed in co-transfected neurons. These results suggest that MCT2 could influence AMPA receptor trafficking within neurons by modulating GluR2 sorting between different subcellular compartments.

Self-Navigation with Compressed Sensing for 2D Translational Motion Correction in Free-Breathing Coronary MRI: A Feasibility Study.

PURPOSE: Respiratory motion correction remains a challenge in coronary magnetic resonance imaging (MRI) and current techniques, such as navigator gating, suffer from sub-optimal scan efficiency and ease-of-use. To overcome these limitations, an image-based self-navigation technique is proposed that uses "sub-images" and compressed sensing (CS) to obtain translational motion correction in 2D. The method was preliminarily implemented as a 2D technique and tested for feasibility for targeted coronary imaging. METHODS: During a 2D segmented radial k-space data acquisition, heavily undersampled sub-images were reconstructed from the readouts collected during each cardiac cycle. These sub-images may then be used for respiratory self-navigation. Alternatively, a CS reconstruction may be used to create these sub-images, so as to partially compensate for the heavy undersampling. Both approaches were quantitatively assessed using simulations and in vivo studies, and the resulting self-navigation strategies were then compared to conventional navigator gating. RESULTS: Sub-images reconstructed using CS showed a lower artifact level than sub-images reconstructed without CS. As a result, the final image quality was significantly better when using CS-assisted self-navigation as opposed to the non-CS approach. Moreover, while both self-navigation techniques led to a 69% scan time reduction (as compared to navigator gating), there was no significant difference in image quality between the CS-assisted self-navigation technique and conventional navigator gating, despite the significant decrease in scan time. CONCLUSIONS: CS-assisted self-navigation using 2D translational motion correction demonstrated feasibility of producing coronary MRA data with image quality comparable to that obtained with conventional navigator gating, and does so without the use of additional acquisitions or motion modeling, while still allowing for 100% scan efficiency and an improved ease-of-use. In conclusion, compressed sensing may become a critical adjunct for 2D translational motion correction in free-breathing cardiac imaging with high spatial resolution. An expansion to modern 3D approaches is now warranted.

Prevalence of sleep-disordered breathing in the general population: the HypnoLaus study.

BACKGROUND: Sleep-disordered breathing is associated with major morbidity and mortality. However, its prevalence has mainly been selectively studied in populations at risk for sleep-disordered breathing or cardiovascular diseases. Taking into account improvements in recording techniques and new criteria used to define respiratory events, we aimed to assess the prevalence of sleep-disordered breathing and associated clinical features in a large population-based sample. METHODS: Between Sept 1, 2009, and June 30, 2013, we did a population-based study (HypnoLaus) in Lausanne, Switzerland. We invited a cohort of 3043 consecutive participants of the CoLaus/PsyCoLaus study to take part. Polysomnography data from 2121 people were included in the final analysis. 1024 (48%) participants were men, with a median age of 57 years (IQR 49-68, range 40-85) and mean body-mass index (BMI) of 25·6 kg/m(2) (SD 4·1). Participants underwent complete polysomnographic recordings at home and had extensive phenotyping for diabetes, hypertension, metabolic syndrome, and depression. The primary outcome was prevalence of sleep-disordered breathing, assessed by the apnoea-hypopnoea index. FINDINGS: The median apnoea-hypopnoea index was 6·9 events per h (IQR 2·7-14·1) in women and 14·9 per h (7·2-27·1) in men. The prevalence of moderate-to-severe sleep-disordered breathing (≥15 events per h) was 23·4% (95% CI 20·9-26·0) in women and 49·7% (46·6-52·8) in men. After multivariable adjustment, the upper quartile for the apnoea-hypopnoea index (>20·6 events per h) was associated independently with the presence of hypertension (odds ratio 1·60, 95% CI 1·14-2·26; p=0·0292 for trend across severity quartiles), diabetes (2·00, 1·05-3·99; p=0·0467), metabolic syndrome (2·80, 1·86-4·29; p<0·0001), and depression (1·92, 1·01-3·64; p=0·0292). INTERPRETATION: The high prevalence of sleep-disordered breathing recorded in our population-based sample might be attributable to the increased sensitivity of current recording techniques and scoring criteria. These results suggest that sleep-disordered breathing is highly prevalent, with important public health outcomes, and that the definition of the disorder should be revised. FUNDING: Faculty of Biology and Medicine of Lausanne, Lausanne University Hospital, Swiss National Science Foundation, Leenaards Foundation, GlaxoSmithKline, Ligue Pulmonaire Vaudoise.