Absence of Bim sensitizes mice to experimental Trypanosoma cruzi infection

Chagas disease is a life-threatening disorder caused by the protozoan parasite Trypanosoma cruzi. Parasite-specific antibodies, CD8⁺ T cells, as well as IFN-γ and nitric oxide (NO) are key elements of the adaptive and innate immunity against the extracellular and intracellular forms of the parasite. Bim is a potent pro-apoptotic member of the Bcl-2 family implicated in different aspects of the immune regulation, such as negative selection of self-reactive thymocytes and elimination of antigen-specific T cells at the end of an immune response. Interestingly, the role of Bim during infections remains largely unidentified. To explore the role of Bim in Chagas disease, we infected WT, Bim^+/−, Bim^−/− mice with trypomastigotes forms of the Y strain of T. cruzi. Strikingly, our data revealed that Bim^−/− mice exhibit a delay in the development of parasitemia followed by a deficiency in the control of parasite load in the bloodstream and a decreased survival compared to WT and Bim^+/− mice. At the peak of parasitemia, peritoneal macrophages of Bim^−/− mice exhibit decreased NO production, which correlated with a decrease in the pro-inflammatory Small Peritoneal Macrophage (SPM) subset. A similar reduction in NO secretion, as well as in the pro-inflammatory cytokines IFN-γ and IL-6, was also observed in Bim^−/− splenocytes. Moreover, an impaired anti-T. cruzi CD8⁺ T-cell response was found in Bim^−/− mice at this time point. Taken together, our results suggest that these alterations may contribute to the establishment of a delayed yet enlarged parasitic load observed at day 9 after infection of Bim^−/− mice and place Bim as an important protein in the control of T. cruzi infections.Subject terms: Cell death and immune response, Infectious diseases     

Anti-inflammatory effects of inosine in allergic lung inflammation in mice: evidence for the participation of adenosine A2A and A3 receptors

Inosine, a naturally occurring purine formed from the breakdown of adenosine, is associated with immunoregulatory effects. Evidence shows that inosine modulates lung inflammation and regulates cytokine generation. However, its role in controlling allergen-induced lung inflammation has yet to be identified. In this study, we aimed to investigate the role of inosine and adenosine receptors in a murine model of lung allergy induced by ovalbumin (OVA). Intraperitoneal administration of inosine (0.001–10 mg/kg, 30 min before OVA challenge) significantly reduced the number of leukocytes, macrophages, lymphocytes and eosinophils recovered in the bronchoalveolar lavage fluid of sensitized mice compared with controls. Interestingly, our results showed that pre-treatment with the selective A_2A receptor antagonist (ZM241385), but not with the selective A_2B receptor antagonist (alloxazine), reduced the inhibitory effects of inosine against macrophage count, suggesting that A_2A receptors mediate monocyte recruitment into the lungs. In addition, the pre-treatment of mice with selective A₃ antagonist (MRS3777) also prevented inosine effects against macrophages, lymphocytes and eosinophils. Histological analysis confirmed the effects of inosine and A_2A adenosine receptors on cell recruitment and demonstrated that the treatment with ZM241385 and alloxazine reverted inosine effects against mast cell migration into the lungs. Accordingly, the treatment with inosine reduced lung elastance, an effect related to A₂ receptors. Moreover, inosine reduced the levels of Th₂-cytokines, interleukin-4 and interleukin-5, an effect that was not reversed by A_2A or A_2B selective antagonists. Our data show that inosine acting on A_2A or A₃ adenosine receptors can regulate OVA-induced allergic lung inflammation and also implicate inosine as an endogenous modulator of inflammatory processes observed in the lungs of asthmatic patients.     

Performance assessment of semiempirical molecular orbital methods in the structural prediction of Sb(III) and Bi(III) complexes

In this paper we carried out a systematic study in order to assess the quality of some semiempirical methods (AM1, PM3 and PM6), comparing predicted structural properties of many Sb(III) and Bi(III) complexes with the corresponding experimental data, indicating which one is more appropriate to describe the structure of such compounds. Root-mean squared deviation (RMSD) and unsigned mean error (UME) were used to evaluate the accuracy of the semiempirical methods to predict the ground state geometries of complexes with many ligand types. Our results have shown that, in general, PM3 predicts more accurately the geometry of Sb(III) complexes, being considered by us as the method of choice to study Sb(III) complexes with a great variety of ligands. PM6 is indicated as the method of choice to study Bi(III) complexes with many types of ligands and also to study Sb(III) thiocompounds, even though PM6 showed an inability to reproduce Sb-N bonds for complexes with flexible ligands, presenting an average deviation of 71.5 % compared the X-ray data.     

Tamoxifen in breast cancer ipse dixit in uterine malignant mixed Müllerian tumor and sarcoma—A report of 8 cases and review of the literature

Aim

Report the outcome of 8 patients (pts) with breast cancer (BC) treated with Tamoxifen (TAM) that developed malignant mixed Müllerian tumor (MMMT) and rare uterine sarcoma (RUS).

Patients and methods

Retrospective study based on data collected from the department medical records between April 1999 and September 2010 among 583 pts with endometrial cancer, 36 pts with MMMT and RUS histopathology. Among them, 8 pts underwent TAM between 4 and 10 years due to a previous diagnosis of BC; all pts were post-menopausal with regular gynecological surveillance; 6 pts (75%) with abnormal uterine bleeding. The diagnosis of 6 pts (MMMT) and 2 pts (RUS) occurred at median interval of 8 years (range 4–12) after initial BC treatment. Pts underwent surgical treatment and were staged as stage I (3pts), IIIA (3pts) and IIIC (2 pts) (FIGO 1988); followed by whole pelvis irradiation (50 Gy) and intracavitary HDR brachytherapy boost (24 Gy). Two pts underwent chemotherapy (CT). Overall and disease free survival was calculated by Kaplan Meier method.

Results

With a median follow-up of 47 months (range 17–130), 3 pts remain alive recurrence-free of BC and RUS. Four pts died with distant metastasis within the first follow-up year, without BC. One pt died from non-related cancer cause. No evidence of local recurrence was found in the whole group of pts. At two years, DFS and OS were 40% and 80%, respectively.

Conclusion

As reported in the literature, TAM administration and causal effect on MMMT and RUS in BC pts is still unknown. No reports about outcome from these specific pts were found.     

Morpho-environmental characterization of the genus Baldellia Parl. (Alismataceae) in the Iberian Peninsula,Balearic islands and North Morocco

Abstract

The genus Baldellia Parl. has always been a complex taxon. Three species and three subspecies have been proposed for the Iberian Peninsula. The morphological variation of this genus in the Iberian Peninsula, Balearic islands and northern Morocco, and its thermo-pluviometric and altitudinal correlation are the focus of this contribution. Twenty-eight morphological variables were examined and subjected to a multivariate statistical analysis. The three morphotypes observed (Form 1, which includes B. ranunculoides subsp. repens and B. alpestris; Form 2, which includes B. ranunculoides and Form 3 – for the new combination B. ranunculoides subsp. ranunculoides var. tangerina (Pau) J. Rocha, A. Crespí, M. García-Barriuso, R. Almeida, J. Honrado, comb. nova proposed here for the first time) seem to represent different reproductive strategies. Morphological variables related with the presence or absence of stolons and the architecture of the inflorescence; the size and number of fruits are the most discriminating variables. Form 1 represents the asexual morphotype; Forms 2 and 3 correspond to morphotypes for which sexual reproduction is preferential. The environmental approach revealed that the asexual form (Form 1) grows in temperate, in more humid conditions, and within a broad altitudinal range. In contrast, the two sexual forms are more common in warmer and drier conditions, and occur over a narrower interval of altitudes.     

Development and validation of an experimental life support system for assessing the effects of global climate change and environmental contamination on estuarine and coastal marine benthic communities

An experimental life support system (ELSS) was constructed to study the interactive effects of multiple stressors on coastal and estuarine benthic communities, specifically perturbations driven by global climate change and anthropogenic environmental contamination. The ELSS allows researchers to control salinity, pH, temperature, ultraviolet radiation (UVR), tidal rhythms and exposure to selected contaminants. Unlike most microcosms previously described, our system enables true independent replication (including randomization). In addition to this, it can be assembled using commercially available materials and equipment, thereby facilitating the replication of identical experimental setups in different geographical locations. Here, we validate the reproducibility and environmental quality of the system by comparing chemical and biological parameters recorded in our ELSS with those prevalent in the natural environment. Water, sediment microbial community and ragworm (the polychaete Hediste diversicolor) samples were obtained from four microcosms after 57 days of operation. In general, average concentrations of dissolved inorganic nutrients (NO₃^?; NH₄⁺ and PO₄^?3) in the water column of the ELSS experimental control units were within the range of concentrations recorded in the natural environment. While some shifts in bacterial community composition were observed between in situ and ELSS sediment samples, the relative abundance of most metabolically active bacterial taxa appeared to be stable. In addition, ELSS operation did not significantly affect survival, oxidative stress and neurological biomarkers of the model organism Hediste diversicolor. The validation data indicate that this system can be used to assess independent or interactive effects of climate change and environmental contamination on benthic communities. Researchers will be able to simulate the effects of these stressors on processes driven by microbial communities, sediment and seawater chemistry and to evaluate potential consequences to sediment toxicity using model organisms such as Hediste diversicolor.     

The role of DNA repair in the pluripotency and differentiation of human stem cells

All living cells utilize intricate DNA repair mechanisms to address numerous types of DNA lesions and to preserve genomic integrity, and pluripotent stem cells have specific needs due to their remarkable ability of self-renewal and differentiation into different functional cell types. Not surprisingly, human stem cells possess a highly efficient DNA repair network that becomes less efficient upon differentiation. Moreover, these cells also have an anaerobic metabolism, which reduces the mitochondria number and the likelihood of oxidative stress, which is highly related to genomic instability. If DNA lesions are not repaired, human stem cells easily undergo senescence, cell death or differentiation, as part of their DNA damage response, avoiding the propagation of stem cells carrying mutations and genomic alterations. Interestingly, cancer stem cells and typical stem cells share not only the differentiation potential but also their capacity to respond to DNA damage, with important implications for cancer therapy using genotoxic agents. On the other hand, the preservation of the adult stem cell pool, and the ability of cells to deal with DNA damage, is essential for normal development, reducing processes of neurodegeneration and premature aging, as one can observe on clinical phenotypes of many human genetic diseases with defects in DNA repair processes. Finally, several recent findings suggest that DNA repair also plays a fundamental role in maintaining the pluripotency and differentiation potential of embryonic stem cells, as well as that of induced pluripotent stem (iPS) cells. DNA repair processes also seem to be necessary for the reprogramming of human cells when iPS cells are produced. Thus, the understanding of how cultured pluripotent stem cells ensure the genetic stability are highly relevant for their safe therapeutic application, at the same time that cellular therapy is a hope for DNA repair deficient patients.     

Age and growth in three populations of Dosinia exoleta (Bivalvia: Veneridae) from the Portuguese coast

The present study aimed at estimating the age and growth in three populations of Dosinia exoleta from the Portuguese coast (Aveiro in the north, Setúbal in the southwest and Faro in the south). Two techniques were compared to ascertain the most suitable method for ageing D. exoleta. Growth marks on the shell surface and acetate peel replicas of sectioned shells were the techniques applied. Two hypotheses were tested: growth parameters present latitudinal variation along the Portuguese coast; growth parameters are influenced by the fishing exploitation. Shell surface rings proved inappropriate for ageing this species, whereas acetate peels provided realistic estimates of the von Bertalanffy growth parameters (K, L _∞ and t ₀). A latitudinal gradient in growth rate was detected, with a clear southward increase in the growth coefficient (K) of D. exoleta (Faro > Setúbal and Aveiro) indicating that warmer waters in southern Portugal provide optimal conditions for the growth of this species. Fishing exploitation in northern Portugal targets larger individuals and leaves behind a younger population of smaller individuals, decreasing the asymptotic shell length (L _∞ ) of D. exoleta from Aveiro. The overall growth performance was compared among populations of D. exoleta and with other venerid species worldwide.     

Geographical variation in shell shape of the pod razor shell Ensis siliqua (Bivalvia: Pharidae)

The present study assessed the existence of variation in the shell shape of the pod razor shell (Ensis siliqua) throughout its distributional range in the north-eastern Atlantic. Shells of E. siliqua caught at seven collecting sites (three in Portugal, three in Spain and one in Ireland) were studied by geometric morphometric methods, using both landmark- and contour-based methods. Both approaches (landmarks inside the valves and shell outline) discriminated the shells from Aveiro (centre of Portugal) and Strangford Lough (Ireland) from those caught in the nearby localities (remaining Portuguese and Spanish sites, maximum distance of 550 km by sea). Landmark analysis revealed that shells from Aveiro were more similar to shells from Ireland (~1,500 km far away). Contour analysis revealed that shells from Aveiro had a shape with a comparatively larger height-to-width ratio, whereas shells from Ireland showed a slightly more curved outline than in the remaining sites. Landmark- and contour-based methods provided coherent complementary information, confirming the usefulness of geometric morphometric analyses for discerning differences in shell shape among populations of E. siliqua. A brief review of previous applications of geometric morphometric methods to modern bivalve species is also provided.