Detection of acute gastrointestinal bleeding by means of technetium-99m in vivo labelled red blood cells

BACKGROUND: Prognosis of gastrointestinal (GI) bleeding depends on the timely [3] and accurate [8, 18] detection of the source of bleeding and sequential surgical or endoscopy therapy. Scintigraphy with red blood cells (RBCs) in vivo labelled by means of technetium-99m hastened detection of source of GI bleeding and improved management of the particular disease. Gastrointestinal endoscopy is the method of choice for the diagnostics of bleeding from upper tract and large bowel. For diagnostics of bleeding from the small bowel we can use scintigraphy with in vivo labelled autological red blood cells if pushenteroscopy, intra-operative enteroscopy or angiography are not available. MATERIAL AND METHODS: 31 patients (13 men, 18 women, aged 20-91, mean 56 years) underwent this investigation from 1998 till 2001 at the Department of Nuclear Medicine. All patients had melaena or enterorrhagia associated with acute anaemia. Gastroscopy, colonoscopy, enteroclysis or X-ray angiography did not detect the source of bleeding. RESULTS: Twenty-one patients had positive scintigraphy with in vivo labelled RBCs - 9 patients were already positive on dynamic scintigraphy, and 12 patients were positive on static images. Scintigraphy with in vivo labelled RBCs was negative in 10 patients. GI bleeding stopped spontaneously in these 10 patients with negative scintigraphy. These patients did not undergo intra- operative enteroscopy or surgery. The final diagnosis of the 21 patients with positive scintigraphy was determined in 16 patients by push-enteroscopy (6 patients), intra-operative enteroscopy (6 patients) or by surgery (4 patients). Of these 16 patients the correct place of bleeding was determined by scintigraphy with labelled RBCs in 11 (69%) patients. Final diagnoses of our 16 patients with positive scintigraphy with autological labelled RBCs were: bleeding small bowel arteriovenous malformation (6 patients), uraemic enteritis with bleeding erosions in ileum and jejunum (2 patients), Osler-Rendu- Weber disease (1 patient), pseudocyst of the pancreas with bleeding vessel communicating to the transverse colon (1 patient), bleeding submucose varix in jejunum (1 patient), carcinoid of the ileum (1 patient), bleeding from the ileosigmoideoanastomosis six days after hemicolectomy for Crohn´s disease (1 patient), bleeding from an ulcer close to the papilla of Vater (1 patient), bleeding from ulcer at jejunum after revious NSAIDs treatment (1 patient), bleeding inflammatory polyp at ileotransversoanastomosis (1 patient). GI bleeding stopped spontaneously in 5 patients with positive scintigraphy. Therefore these patients did not undergo intraoperative enteroscopy or surgery and we could not determine the final diagnosis. CONCLUSIONS: Scintigraphy with RBCs in vivo labelled technetium- 99m hastened detection of the source of GI bleeding and improved management of the source of GI bleeding and improved management of disease

Eye Tracking Using Nonverbal Tasks Could Contribute to Diagnostics of Developmental Dyslexia and Developmental Language Disorder

There are not many studies dealing with a comparison of the eye movements of individuals with dyslexia and developmental language disorder (DLD). The aim of this study is to compare the eye movements in the two most common language disorders, dyslexia and DLD and to consider their contribution to diagnostics. In the research the oculomotor test was administered to 60 children with the clinical diagnosis of dyslexia or DLD and 58 typically developing children (controls). The test included a prosaccadic task, antisaccadic task and a nonverbal sequential task with self-regulation of the pace. Controls could be singled out from other two clinical groups by means of the oculomotor imaging. Both of the clinical groups in comparison with the controls were characterized by worse overall performance. Through the employment of the oculomotor it was possible to differentiate between both of the clinical groups. The dyslexics had an overall worse oculomotor performance than the DLD group. The results of the study show that the oculomotor test has the potential to contribute to diagnostics of dyslexia and DLD and the screening of these disorders at pre-school age

Uporaba voltmetrije za određivanje tiola i metalotioneina male molekularne mase u krvi svinje (Sus scrofa domestica)

Metallothioneins (MT) play a key role in maintaining the homeostasis of essential metals and in protecting of cells against metal toxicity as well as cell oxidative damaging. The aim of this work is to propose a new approach for processing a biological sample for analysis of thiols including metallothioneins. Moreover, the proposed procedure is tested on quantification of MT and total thiol content in blood serum of pig (Sus scrofa domestica), which has not been previously been performed. The blood serum (10 ml) was collected and transferred to 0.2 M phosphate buffer (990 ml). The sample (100 × diluted) was placed in a thermomixer, where heat denaturation of most of the proteins proceeded. The processed blood serum sample was electrochemically measured to determine total content of thiols (cysteine, glutathione, metallothionein and other low molecular thermostable thiols) and content of MT. The average level of the thiols and MT were estimated as 165 ± 20 mM and 5.2 ± 0.6 mM, respectively.Metalotioneini (MT) igraju ključnu ulogu u održavanju homeostaze esencijalnih metala i u zaštiti od toksičnih metala te od oštećivanja stanice oksidacijom. Cilj ovog rada je predložiti novi pristup obradi bioloških uzoraka za analizu tiola, uključujući metalotioneine. Osim toga, predloženi postupak se testira pri kvantifikaciji MT i ukupnog sadržaja tiola u krvnom serumu svinje (Sus scrofa domestica), što se dosad nije radilo. Prikupljan je krvni serum (10 ml) te prebacivan u 0.2 M fosfatni pufer (990 ml). Uzorak (100 × razrijeđen) je stavljen u termomikser gdje se nastavila toplinska denaturacija većine proteina. Obrađeni uzorak seruma je elektrokemijski izmjeren da bi se odredio ukupni sadržaj tiola (cistein, glutation, metalotionein i drugi termostabilni tioli male molekularne mase) te sadržaj MT. Prosječna razina tiola i MT su procijenjeni na 165 ± 20 mM, odnosno 5.2 ± 0.6 mM

Biotic homogenization destabilizes ecosystem functioning by decreasing spatial asynchrony

Our planet is facing significant changes of biodiversity across spatial scales. Although the negative effects of local biodiversity (α diversity) loss on ecosystem stability are well documented, the consequences of biodiversity changes at larger spatial scales, in particular biotic homogenization, that is, reduced species turnover across space (β diversity), remain poorly known. Using data from 39 grassland biodiversity experiments, we examine the effects of β diversity on the stability of simulated landscapes while controlling for potentially confounding biotic and abiotic factors. Our results show that higher β diversity generates more asynchronous dynamics among local communities and thereby contributes to the stability of ecosystem productivity at larger spatial scales. We further quantify the relative contributions of α and β diversity to ecosystem stability and find a relatively stronger effect of α diversity, possibly due to the limited spatial scale of our experiments. The stabilizing effects of both α and β diversity lead to a positive diversity–stability relationship at the landscape scale. Our findings demonstrate the destabilizing effect of biotic homogenization and suggest that biodiversity should be conserved at multiple spatial scales to maintain the stability of ecosystem functions and services

Global patterns and drivers of alpine plant species richness

Aim Alpine ecosystems differ in area, macroenvironment and biogeographical history across the Earth, but the relationship between these factors and plant species richness is still unexplored. Here, we assess the global patterns of plant species richness in alpine ecosystems and their association with environmental, geographical and historical factors at regional and community scales. Location Global. Time period Data collected between 1923 and 2019. Major taxa studied Vascular plants. Methods We used a dataset representative of global alpine vegetation, consisting of 8,928 plots sampled within 26 ecoregions and six biogeographical realms, to estimate regional richness using sample‐based rarefaction and extrapolation. Then, we evaluated latitudinal patterns of regional and community richness with generalized additive models. Using environmental, geographical and historical predictors from global raster layers, we modelled regional and community richness in a mixed‐effect modelling framework. Results The latitudinal pattern of regional richness peaked around the equator and at mid‐latitudes, in response to current and past alpine area, isolation and the variation in soil pH among regions. At the community level, species richness peaked at mid‐latitudes of the Northern Hemisphere, despite a considerable within‐region variation. Community richness was related to macroclimate and historical predictors, with strong effects of other spatially structured factors. Main conclusions In contrast to the well‐known latitudinal diversity gradient, the alpine plant species richness of some temperate regions in Eurasia was comparable to that of hyperdiverse tropical ecosystems, such as the páramo. The species richness of these putative hotspot regions is explained mainly by the extent of alpine area and their glacial history, whereas community richness depends on local environmental factors. Our results highlight hotspots of species richness at mid‐latitudes, indicating that the diversity of alpine plants is linked to regional idiosyncrasies and to the historical prevalence of alpine ecosystems, rather than current macroclimatic gradients

Species-area relationships in continuous vegetation : evidence from Palaearctic grasslands

Aim Species–area relationships (SARs) are fundamental scaling laws in ecology although their shape is still disputed. At larger areas, power laws best represent SARs. Yet, it remains unclear whether SARs follow other shapes at finer spatial grains in continuous vegetation. We asked which function describes SARs best at small grains and explored how sampling methodology or the environment influence SAR shape. Location Palaearctic grasslands and other non‐forested habitats. Taxa Vascular plants, bryophytes and lichens. Methods We used the GrassPlot database, containing standardized vegetation‐plot data from vascular plants, bryophytes and lichens spanning a wide range of grassland types throughout the Palaearctic and including 2,057 nested‐plot series with at least seven grain sizes ranging from 1 cm2 to 1,024 m2. Using nonlinear regression, we assessed the appropriateness of different SAR functions (power, power quadratic, power breakpoint, logarithmic, Michaelis–Menten). Based on AICc, we tested whether the ranking of functions differed among taxonomic groups, methodological settings, biomes or vegetation types. Results The power function was the most suitable function across the studied taxonomic groups. The superiority of this function increased from lichens to bryophytes to vascular plants to all three taxonomic groups together. The sampling method was highly influential as rooted presence sampling decreased the performance of the power function. By contrast, biome and vegetation type had practically no influence on the superiority of the power law. Main conclusions We conclude that SARs of sessile organisms at smaller spatial grains are best approximated by a power function. This coincides with several other comprehensive studies of SARs at different grain sizes and for different taxa, thus supporting the general appropriateness of the power function for modelling species diversity over a wide range of grain sizes. The poor performance of the Michaelis–Menten function demonstrates that richness within plant communities generally does not approach any saturation, thus calling into question the concept of minimal area.publishedVersio

Distance decay 2.0-A global synthesis of taxonomic and functional turnover in ecological communities

Aim: Understanding the variation in community composition and species abundances (i.e., beta-diversity) is at the heart of community ecology. A common approach to examine beta-diversity is to evaluate directional variation in community composition by measuring the decay in the similarity among pairs of communities along spatial or environmental distance. We provide the first global synthesis of taxonomic and functional distance decay along spatial and environmental distance by analysing 148 datasets comprising different types of organisms and environments. Location: Global. Time period: 1990 to present. Major taxa studied: From diatoms to mammals. Method: We measured the strength of the decay using ranked Mantel tests (Mantel r) and the rate of distance decay as the slope of an exponential fit using generalized linear models. We used null models to test whether functional similarity decays faster or slower than expected given the taxonomic decay along the spatial and environmental distance. We also unveiled the factors driving the rate of decay across the datasets, including latitude, spatial extent, realm and organismal features. Results: Taxonomic distance decay was stronger than functional distance decay along both spatial and environmental distance. Functional distance decay was random given the taxonomic distance decay. The rate of taxonomic and functional spatial distance decay was fastest in the datasets from mid-latitudes. Overall, datasets covering larger spatial extents showed a lower rate of decay along spatial distance but a higher rate of decay along environmental distance. Marine ecosystems had the slowest rate of decay along environmental distances. Main conclusions: In general, taxonomic distance decay is a useful tool for biogeographical research because it reflects dispersal-related factors in addition to species responses to climatic and environmental variables. Moreover, functional distance decay might be a cost-effective option for investigating community changes in heterogeneous environments

The 2018 European heatwave led to stem dehydration but not to consistent growth reductions in forests

Heatwaves exert disproportionately strong and sometimes irreversible impacts on forest ecosystems. These impacts remain poorly understood at the tree and species level and across large spatial scales. Here, we investigate the effects of the record-breaking 2018 European heatwave on tree growth and tree water status using a collection of high-temporal resolution dendrometer data from 21 species across 53 sites. Relative to the two preceding years, annual stem growth was not consistently reduced by the 2018 heatwave but stems experienced twice the temporary shrinkage due to depletion of water reserves. Conifer species were less capable of rehydrating overnight than broadleaves across gradients of soil and atmospheric drought, suggesting less resilience toward transient stress. In particular, Norway spruce and Scots pine experienced extensive stem dehydration. Our high-resolution dendrometer network was suitable to disentangle the effects of a severe heatwave on tree growth and desiccation at large-spatial scales in situ, and provided insights on which species may be more vulnerable to climate extremes