1,024 research outputs found

    Small steps towards the potential of ‘preventive’ treatment of early phosphate loading in chronic kidney disease patients

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    Few clinical studies have investigated the value of phosphate (P)-lowering therapies in early chronic kidney disease (CKD) patients in whom hyperphosphataemia has not yet clearly developed and they report conflicting and even unexpected results. In this issue of Clinical Kidney Journal, de Krijger et al. found that sevelamer carbonate (4.8 g/day for 8 weeks) did not induce a significant reduction of pulse wave velocity (PWV) and that fibroblast growth factor 23 (FGF23) did not decrease despite a decline in 24-h urine P excretion. To some extent these findings challenge the concept that 'preventive' P binder therapy to lower FGF23 is a useful approach, at least over this short period of time. Interestingly, in a subgroup of patients with absent or limited abdominal vascular calcification, treatment did result in a statistically significant reduction in adjusted PWV, suggesting that PWV is amenable to improvement in this subset. Interpretation of the scarce and heterogeneous observations described in early CKD remains difficult and causality and/or the possibility of 'preventive' treatment may not yet be completely disregarded. Moreover, de Krijger et al. contribute to the identification of new sources of bias and methodological issues that may lead to more personalized treatments, always bearing in mind that not all patients and not all P binders are equal

    Dissecting the genetic basis for seed coat mucilage heteroxylan biosynthesis in plantago ovata using gamma irradiation and infrared spectroscopy

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    Seeds from the myxospermous species Plantago ovata release a polysaccharide-rich mucilage upon contact with water. This seed coat derived mucilage is composed predominantly of heteroxylan (HX) and is utilized as a gluten-free dietary fiber supplement to promote human colorectal health. In this study, a gamma-irradiated P. ovata population was generated and screened using histological stains and Fourier Transform Mid Infrared (FTMIR) spectroscopy to identify putative mutants showing defects in seed coat mucilage HX composition and/or structure. FTMIR analysis of dry seed revealed variation in regions of the IR spectra previously linked to xylan structure in Secale cereale (rye). Subsequent absorbance ratio and PCA multivariate analysis identified 22 putative mutant families with differences in the HX IR fingerprint region. Many of these showed distinct changes in the amount and subtle changes in structure of HX after mucilage extrusion, while 20% of the putative HX mutants identified by FTMIR showed no difference in staining patterns of extruded mucilage compared to wild-type. Transcriptional screening analysis of two putative reduced xylan in mucilage (rxm) mutants, rxm1 and rxm3, revealed that changes in HX levels in rxm1 correlate with reduced transcription of known and novel genes associated with xylan synthesis, possibly indicative of specific co-regulatory units within the xylan biosynthetic pathway. These results confirm that FTMIR is a suitable method for identifying putative mutants with altered mucilage HX composition in P. ovata, and therefore forms a resource to identify novel genes involved in xylan biosynthesis.Matthew R. Tucker, Chao Ma, Jana Phan, Kylie Neumann, Neil J. Shirley, Michael G. Hahn, Daniel Cozzolino and Rachel A. Burto

    A multidisciplinary review of the science of vitamin D receptor activation

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    Our understanding of the vitamin D receptor (VDR) and the effects of VDR activation has changed dramatically in recent years, with the publication of several new studies looking at selective VDR activation and effects on the cardio-renal syndrome (CRS).1 These advances have the potential to change the perspective of VDR activation beyond its role in mineral metabolism. Pleiotropic vitamin D effects have come into the focus of interest

    Pollinator convergence and the nature of species' boundaries in sympatric Sardinian Ophrys (Orchidaceae)

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    Background and Aims In the sexually deceptive Ophrys genus, species isolation is generally considered ethological and occurs via different, specific pollinators, but there are cases in which Ophrys species can share a common pollinator and differ in pollen placement on the body of the insect. In that condition, species are expected to be reproductively isolated through a pre-mating mechanical barrier. Here, the relative contribution of pre- vs. post-mating barriers to gene flow among two Ophrys species that share a common pollinator and can occur in sympatry is studied. Methods A natural hybrid zone on Sardinia between O. iricolor and O. incubacea, sharing Andrena morio as pollinator, was investigated by analysing floral traits involved in pollinator attraction as odour extracts both for non-active and active compounds and for labellum morphology. The genetic architecture of the hybrid zone was also estimated with amplified fragment length polymorphism (AFLP) markers, and pollination fitness and seed set of both parental species and their hybrids in the sympatric zone were estimated by controlled crosses. Key Results Although hybrids were intermediate between parental species in labellum morphology and non-active odour compounds, both parental species and hybrids produced a similar odour bouquet for active compounds. However, hybrids produced significantly lower fruit and seed set than parental species, and the genetic architecture of the hybrid zone suggests that they were mostly first-generation hybrids. Conclusions The two parental species hybridize in sympatry as a consequence of pollinator overlap and weak mechanical isolation, but post-zygotic barriers reduce hybrid frequency and fitness, and prevent extensive introgression. These results highlight a significant contribution of late post-mating barriers, such as chromosomal divergence, for maintaining reproductive isolation, in an orchid group for which pre-mating barriers are often considered predominan

    Self-related consequences of death fear and death denial

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    This study explores self-related outcomes (e.g., esteem, self-concept clarity, existential well-being) as a function of the interaction between self-reported levels of death fear and death denial. Consistent with the idea that positive existential growth can come from individuals facing, rather than denying, their mortality (Cozzolino, 2006), the authors observed that not fearing and denying death can bolster important positive components of the self. That is, individuals low in death denial and death fear evidenced an enhanced self that is valued, clearly conceived, efficacious, and that has meaning and purpose

    Hidden genetic variation in plasticity provides the potential for rapid adaptation to novel environments

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    Rapid environmental change is forcing populations into novel environments where plasticity will no longer maintain fitness. When populations are exposed to novel environments, evolutionary theory predicts that genetic variation in fitness will increase and should be associated with genetic differences in plasticity. If true, then genetic variation in plasticity can increase adaptive potential in novel environments, and population persistence via rapid adaptation is more likely. To test whether genetic variation in fitness increases in novel environments and is associated with plasticity, we transplanted 8,149 clones of 314 genotypes of a Sicilian daisy (Senecio chrysanthemifolius) within and outside its native range, and quantified genetic variation in fitness, and plasticity in leaf traits and gene expression. Although mean fitness declined by 87% in the novel environment, genetic variance in fitness increased threefold and was correlated with plasticity in leaf traits. High fitness genotypes showed greater plasticity in gene expression, but lower plasticity in most leaf traits. Interestingly, genotypes with greater fitness in the novel environment had the lowest fitness at the native site. These results suggest that standing genetic variation in plasticity could help populations to persist and adapt to novel environments, despite remaining hidden in native environments

    Comparison of SST L3 products generated from the AVHRR and MODIS sensors in front of the San Jorge Gulf, Argentina

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    [EN] Since the early 1980s, the AVHRR sensor on board the NOAA satellites has provided SST estimates to the scientific community in general. Towards the end of the 1990s, a new generation of radiometers was added, combining a wider range of spectral measurements with improvements in technology, such as the MODIS sensor on board the Terra and Aqua satellites. The development of this last sensor was based on the years of NOAA/AVHRR series. Understanding the relationship between products derived from different sensors is critical to the continuous long-term monitoring of any variable and the construction of continuous time series. The objective of this work was to make a comparison of the monthly SST values for the 2003-2006 period calculated from data from the NOAA/ AVHRR series versus Aqua-MODIS on a sector of the middle Argentina Continental shelf off the San Jorge Gulf. For both sensors, the isotherms show a similar distribution pattern in all months. Pearson’s correlation coefficient was high, both in the seasonal (> 0.9) and monthly (> 0.8) analyzes. The comparative analysis of the temperature estimated by both sensors shows that SST products are similar and can be used to analyze large and continuous time series.[ES] Desde principios de la década de los 80, el sensor AVHRR a bordo de los satélites NOAA ha provisto de estimaciones de la temperatura de la superficie del mar (TSM) a la comunidad científica en general. Hacia finales de la década de los 90, surge una nueva generación de radiómetros que combinan una mayor gama de mediciones espectrales con mejoras en la tecnología, como lo es el sensor MODIS a bordo de los satélites Terra y Aqua. El desarrollo de este último sensor se basó en los años de trayectoria de la serie NOAA/AVHRR. La comprensión de la relación entre los productos derivados de distintos sensores es fundamental para el seguimiento continuo a largo plazo de cualquier variable y de la construcción de serie de tiempos combinados. El objetivo del presente trabajo fue realizar una comparación de los valores mensuales de TSM para el período 2003-2006 calculadas a partir de datos de la serie NOAA/AVHRR vs Aqua/MODIS sobre un sector de la Plataforma Continental Argentina frente al Golfo San Jorge. El análisis de las isotermas muestra un patrón de distribución similar durante todos los meses para ambos sensores. El coeficiente de correlación de Pearson tanto en el análisis estacional como mensual fue alto (> 0,8). El análisis comparativo de la temperatura medida en ambos sensores muestra que los productos de TSM son similares, teniendo en cuenta que la diferencia media de temperatura entre ambos sensores es inferior a 0,5ºC. Por lo tanto, para el estudio de largas series de tiempo de TSM en la plataforma continental argentina se puede utilizar en forma continua las mediciones de Aqua/MODIS, cuando ya no se disponen las de NOAA/AVHRR.A la Dra. Eleonora Verón, la Dra. Martina Camiolo y al Lic. Raúl Reta por sus aportes y correcciones. Este trabajo fue financiado por el Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP). Número de contribución INIDEP 2081.Allega, L.; Cozzolino, E.; Pisoni, JP.; Piccolo, MC. (2017). Comparación de los productos de TSM L3 generados a partir de los sensores AVHRR y MODIS frente al Golfo San Jorge, Argentina. Revista de Teledetección. (50):17-26. https://doi.org/10.4995/raet.2017.7498SWORD17265

    Bone biopsy practice patterns across Europe: the European renal osteodystrophy initiative - a position paper

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    Renal osteodystrophy (ROD) is a heterogeneous group of metabolic bone diseases complicating progressive chronic kidney disease (CKD). Bone biomarkers and bone imaging techniques may help to assess bone health and predict fractures in CKD but do have important inherent limitations. By informing on bone turnover and mineralization, a bone biopsy may help to guide prevention and treatment of ROD and its consequences. According to a recent survey conducted among European nephrologists, bone biopsies are performed rather exceptionally, both for clinical and research purposes. Obviously, clinical research in the field of ROD is threatened by vanishing clinical and pathological expertise, small patient cohorts and scientific isolation. In March 2016, the European Renal Osteodystrophy (EU-ROD) initiative was created under the umbrella of the ERA-EDTA CKD-mineral and bone disorder (MBD) Working Group to revitalize bone biopsy as a clinically useful tool in the diagnostic workup of CKD-MBD and to foster research on the epidemiology, implications and reversibility of ROD. As such, the EU-ROD initiative aims to increase the understanding of ROD and ultimately to improve outcomes in CKD patients
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