Turbellarian assemblages in freshwater lagoons in southern Brazil

Turbellarians, which typically feed on bacteria, algae, rotifers, oligochaetes, dipteran larvae, microcrustaceans, and other organisms, are abundant in diverse types of wetlands. Despite their importance, abundance, and species richness in freshwater environments, turbellarians are seldom considered in studies on biodiversity. We analyzed the structure of turbellarian communities in shore areas of three categories of permanent wetlands classified according to their perimeter as small, intermediate, and large during an annual cycle. In total, 1847 turbellarians were collected representing 42 species and 15 genera, from the orders Catenulida, Macrostomida, Lecithoepitheliata, Rhabdocoela, and Tricladida. Sixteen species were common to the three categories of wetlands, whereas nineteen species were unique to a particular category. Species composition varied among wetlands of different sizes; small, intermediate, and large wetlands had different dominant species. We found seasonal differences in community composition over the year, but no significant differences in mean values of observed species richness among wetlands with different sizes and among seasonal samples. The estimated species richness was, however, higher in the small wetlands, followed by the large and intermediate wetlands. In the summer, abundance was significantly lower in the small water bodies than in the intermediate and large bodies of water. Our results reinforce the need for conservation of wetlands of different sizes.     

FLUKA Monte Carlo simulation for the Leksell Gamma Knife Perfexion radiosurgery system: Homogeneous media

The purpose of this work is to investigate the capability of the FLUKA Monte Carlo (MC) code to simulate the Elekta Leksell Gamma Knife Perfexion (LGK-PFX) and reproduce the Treatment Planning System (TPS) Leksell GammaPlan version 8.2 (LGP) dose calculations for the case of a water equivalent phantom target. Thanks to the collaboration with Elekta Instruments AB, the collimation system geometry, the source positions and all the involved material have been simulated in detail. The relative linear dose distribution along the three coordinate axes, for each collimator size, and the Relative Output Factors (ROF) have been investigated. The simulation has been validated comparing simulated linear dose profiles with measurements performed with EBT radiochromic films. The acceptance criterion between experimental data and FLUKA results is based on the gamma index (GI) method. The FLUKA MC calculation for the ROF provided the values of 0.920 for the 8 mm collimators and 0.800 for the 4 mm collimators. These values are in good agreement with the Elekta reference data of 0.924 and 0.805 respectively. The percentage difference between calculated and reference values for the ROF is under 1% and within the FLUKA uncertainty. Also the simulated relative dose profiles show a good agreement with the LGP calculation expressed by means of the gamma index method. This established accuracy proves that FLUKA is a suitable and powerful tool in order to reproduce successfully the LGP calculations for the homogeneous media.     

Prolonged lifespan with enhanced exploratory behavior in mice overexpressing the oxidized nucleoside triphosphatase hMTH1

The contribution that oxidative damage to DNA and/or RNA makes to the aging process remains undefined. In this study, we used the hMTH1‐Tg mouse model to investigate how oxidative damage to nucleic acids affects aging. hMTH1‐Tg mice express high levels of the hMTH1 hydrolase that degrades 8‐oxodGTP and 8‐oxoGTP and excludes 8‐oxoguanine from both DNA and RNA. Compared to wild‐type animals, hMTH1‐overexpressing mice have significantly lower steady‐state levels of 8‐oxoguanine in both nuclear and mitochondrial DNA of several organs, including the brain. hMTH1 overexpression prevents the age‐dependent accumulation of DNA 8‐oxoguanine that occurs in wild‐type mice. These lower levels of oxidized guanines are associated with increased longevity and hMTH1‐Tg animals live significantly longer than their wild‐type littermates. Neither lipid oxidation nor overall antioxidant status is significantly affected by hMTH1 overexpression. At the cellular level, neurospheres derived from adult hMTH1‐Tg neural progenitor cells display increased proliferative capacity and primary fibroblasts from hMTH1‐Tg embryos do not undergo overt senescence in vitro. The significantly lower levels of oxidized DNA/RNA in transgenic animals are associated with behavioral changes. These mice show reduced anxiety and enhanced investigation of environmental and social cues. Longevity conferred by overexpression of a single nucleotide hydrolase in hMTH1‐Tg animals is an example of lifespan extension associated with healthy aging. It provides a link between aging and oxidative damage to nucleic acids.     

Prognostic impact of coronary microcirculation abnormalities in systemic sclerosis: a prospective study to evaluate the role of non-invasive tests

Introduction

Microcirculation dysfunction is a typical feature of systemic sclerosis (SSc) and represents the earliest abnormality of primary myocardial involvement. We assessed coronary microcirculation status by combining two functional tests in SSc patients and estimating its impact on disease outcome.

Methods

Forty-one SSc patients, asymptomatic for coronary artery disease, were tested for coronary flow velocity reserve (CFR) by transthoracic-echo-Doppler with adenosine infusion (A-TTE) and for left ventricular wall motion abnormalities (WMA) by dobutamine stress echocardiography (DSE). Myocardial multi-detector computed tomography (MDCT) enabled the presence of epicardial stenosis, which could interfere with the accuracy of the tests, to be excluded. Patient survival rate was assessed over a 6.7- ± 3.5-year follow-up.

Results

Nineteen out of 41 (46%) SSc patients had a reduced CFR (≤2.5) and in 16/41 (39%) a WMA was observed during DSE. Furthermore, 13/41 (32%) patients showed pathological CFR and WMA. An inverse correlation between wall motion score index (WMSI) during DSE and CFR value (r = -0.57, P <0.0001) was observed; in addition, CFR was significantly reduced (2.21 ± 0.38) in patients with WMA as compared to those without (2.94 ± 0.60) (P <0.0001). In 12 patients with abnormal DSE, MDCT was used to exclude macrovasculopathy. During a 6.7- ± 3.5-year follow-up seven patients with abnormal coronary functional tests died of disease-related causes, compared to only one patient with normal tests.

Conclusions

A-TTE and DSE tests are useful tools to detect non-invasively pre-clinical microcirculation abnormalities in SSc patients; moreover, abnormal CFR and WMA might be related to a worse disease outcome suggesting a prognostic value of these tests, similar to other myocardial diseases.     

Agricultural intensification in Brazil and its effects on land‐use patterns: an analysis of the 1975–2006 period

Does agricultural intensification reduce the area used for agricultural production in Brazil? Census and other data for time periods 1975–1996 and 1996–2006 were processed and analyzed using Geographic Information System and statistical tools to investigate whether and if so, how, changes in yield and stocking rate coincide with changes in cropland and pasture area. Complementary medium‐resolution data on total farmland area changes were used in a spatially explicit assessment of the land‐use transitions that occurred in Brazil during 1960–2006. The analyses show that in agriculturally consolidated areas (mainly southern and southeastern Brazil), land‐use intensification (both on cropland and pastures) coincided with either contraction of both cropland and pasture areas, or cropland expansion at the expense of pastures, both cases resulting in farmland stability or contraction. In contrast, in agricultural frontier areas (i.e., the deforestation zones in central and northern Brazil), land‐use intensification coincided with expansion of agricultural lands. These observations provide support for the thesis that (i) technological improvements create incentives for expansion in agricultural frontier areas; and (ii) farmers are likely to reduce their managed acreage only if land becomes a scarce resource. The spatially explicit examination of land‐use transitions since 1960 reveals an expansion and gradual movement of the agricultural frontier toward the interior (center‐western Cerrado) of Brazil. It also indicates a possible initiation of a reversed trend in line with the forest transition theory, i.e., agricultural contraction and recurring forests in marginally suitable areas in southeastern Brazil, mainly within the Atlantic Forest biome. The significant reduction in deforestation that has taken place in recent years, despite rising food commodity prices, indicates that policies put in place to curb conversion of native vegetation to agriculture land might be effective. This can improve the prospects for protecting native vegetation by investing in agricultural intensification.     

The utility of epithelial-cell micronuclei in the assessment of intermittent exposures

Epithelial-cell micronuclei (MN) are potentially useful markers of occupational exposure to genotoxicants. With intermittent exposures, cells sampled either before or after a specific time interval, reflecting the time it takes for damaged cells to become available at the epithelial surface, are unlikely to be exposure-related. It may then be important to conduct an exposure-window analysis, with the goal of identifying the relevant exposures.We re-analysed individual exposure data from a previous study (Suruda et al. 1993) of MN formation in 22 male mortuary science students exposed to formaldehyde during a 90-day embalming class. We conducted an exposurewindow analysis and compared the results with those obtained with 90-day cumulative exposure. The window widths varied between 7 and 25 days, in 1 day increments, assuming a constant 7-day cell-cycle. We assessed the fit (likelihood-ratio test) of a linear regression model, regressing the change in buccal MN prevalence on formaldehyde exposure, using both asymptotic and non-asymptotic methods. Exposures defined from 7-15 to 7-18 days before specimen collection provided a slightly better fit than the 90-day cumulative exposure, with a doubling of the regression coefficient for the exposure effect (for the 7-16-days window LR = 5.32, p = 0.032, coefficient = 0.088 MN per 1000 cells per ppm-hr; 95% CI = 0.014, 0.16; for the 90-day cumulative exposure LR = 4.44, p = 0.048, coefficient = 0.045 MN per 1000 cells per ppm-hr, 95% CI = 0.0038, 0.086). Although hampered by the small number of subjects, these results reinforce the potential importance of exposure timing.     

Association between the risk of coronary artery disease in South Asians and a deletion polymorphism in glutathione S-transferase M1

Background: The aim of the present study was to evaluate whether or not an elevated ischaemia-modified albumin (IMA) level provides any additional prognostic information to the validated Thrombolysis In Myocardial Infarction (TIMI) risk score in patients with ST-segment elevation myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (PCI). Methods: One hundred seven consecutive STEMI patients treated with primary PCI were included. The incidence of 30-day death was the prespecified primary end point. Serum IMA was measured immediately at hospital arrival. Results: The incidence of the primary end point was 6.5%. A significant predictive value of IMA in relation to the primary end point was indicated by an area under the ROC curve of 0.71 (p = 0.01). In the multivariate analysis, increased IMA remained a significant predictor of the primary end point after adjustment for TIMI risk predictors (p = 0.019). The area under the ROC curve for the TIMI risk score was 0.68 (p = 0.03). The addition of IMA to the TIMI risk score did not improve its prognostic value (area under the ROC curve 0.60, p = 0.25). Conclusion: IMA levels obtained at admission are a powerful indicator of short-term mortality in STEMI patients treated with primary PCI, but do not seem to be a marker that adds prognostic information to the validated STEMI TIMI risk score.     

Productivity: key factor affecting grazing exclusion effects on vegetation and soil

In this study, we inquire into the effects of short-term goat grazing abandonment on plant species and functional composition, bare ground and net primary productivity (NPP) in two traditionally grazed pastures located in the Canarian Network of Natural Protected Areas and the Natura 2000 Network. In addition, we analyse soil chemical properties, biomass tannin content and energetic value to find out how grazing abandonment affects soil fertility and forage quality of these agroecosystems. Grazing exclusion effects on plant species and functional composition, as well as on soil fertility depended on the productivity of the studied pasture. Erect forbs and shrubs (endemic to Macaronesian region and native) were favoured by grazing removal in the most productive pasture, while soil fertility decreased in the driest and least productive site. An increase in NPP after exclusion was consistent among study sites. Although we consider goat grazing as necessary for maintaining traditional agroecosystems, we also suggest controlling it over time, allowing some periods of rest to give endemic shrub species time to recover from near propagule sources.