Aims. We investigate the present-day photometric properties of the dwarf spheroidal galaxies in the Local Group. From the analysis of their integrated colours, we consider a possible link between ...dwarf spheroidals and giant ellipticals. From the analysis of the MV vs. ($B-V$) plot, we search for a possible evolutionary link between dwarf spheroidal galaxies (dSphs) and dwarf irregular galaxies (dIrrs). Methods. By means of chemical evolution models combined with a spectro-photometric model, we study the evolution of six Local Group dwarf spheroidal galaxies (Carina, Draco, Sagittarius, Sculptor, Sextans and Ursa Minor). The chemical evolution models, which adopt up-to-date nucleosynthesis from low and intermediate mass stars as well as nucleosynthesis and energetic feedback from supernovae type Ia and II, reproduce several observational constraints of these galaxies, such as abundance ratios versus metallicity and the metallicity distributions. The proposed scenario for the evolution of these galaxies is characterised by low star formation rates and high galactic wind efficiencies. Results. Such a scenario allows us to predict integrated colours and magnitudes which agree with observations. Our results strongly suggest that the first few Gyrs of evolution, when the star formation is most active, are crucial to define the luminosities, colours, and other photometric properties as observed today. After the star formation epoch, the galactic wind sweeps away a large fraction of the gas of each galaxy, which then evolves passively. Our results indicate that it is likely that at a certain stage of their evolution, dSphs and dIrrs presented similar photometric properties. However, after that phase, they evolved along different paths, leading them to their disparate present-day properties.
Rhabdomyosarcoma (RMS), which can be classified as embryonal RMS (ERMS) and alveolar RMS (ARMS), represents the most frequent soft tissue sarcoma in the pediatric population; the latter shows greater ...aggressiveness and metastatic potential with respect to the former. Epigenetic alterations in cancer include DNA methylation changes and histone modifications that influence overall gene expression patterns. Different tumor subtypes are characterized by distinct methylation signatures that could facilitate early disease detection and greater prognostic accuracy.
A genome-wide approach was used to examine methylation patterns associated with different prognoses, and DNA methylome analysis was carried out using the Agilent Human DNA Methylation platform. The results were validated using bisulfite sequencing and 5-aza-2'deoxycytidine treatment in RMS cell lines. Some in vitro functional studies were also performed to explore the involvement of a target gene in RMS tumor cells.
In accordance with the Intergroup Rhabdomyosarcoma Study (IRS) grouping, study results showed that distinct methylation patterns distinguish RMS subgroups and that a cluster of protocadherin genes are hypermethylated in metastatic RMS. Among these, PCDHA4, whose expression was decreased by DNA methylation, emerged as a down-regulated gene in the metastatic samples. As PCDHA4-silenced cells have a significantly higher cell proliferation rate paralleled by higher cell invasiveness, PCDHA4 seems to behave as a tumor suppressor in metastatic RMS.
Study results demonstrated that DNA methylation patterns distinguish between metastatic and non-metastatic RMS and suggest that epigenetic regulation of specific genes could represent a novel therapeutic target that could enhance the efficiency of RMS treatments.
The NA62 experiment at the CERN SPS reports the first search for K+→π+νν¯ using the decay-in-flight technique, based on a sample of 1.21×1011K+ decays collected in 2016. The single event sensitivity ...is 3.15×10−10, corresponding to 0.267 Standard Model events. One signal candidate is observed while the expected background is 0.152 events. This leads to an upper limit of 14×10−10 on the K+→π+νν¯ branching ratio at 95% CL.
The chemical evolution of IC 10 Yin, J.; Magrini, L.; Matteucci, F. ...
Astronomy & astrophysics,
09/2010, Letnik:
520
Journal Article
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Odprti dostop
Context. Dwarf irregular galaxies are relatively simple unevolved objects where it is easy to test models of galactic chemical evolution. Aims. We attempt to determine the star formation and gas ...accretion history of IC 10, a local dwarf irregular for which abundance, gas, and mass determinations are available. Methods. We apply detailed chemical evolution models to predict the evolution of several chemical elements (He, O, N, S) and compared our predictions with the observational data. We consider additional constraints such as the present-time gas fraction, the star formation rate (SFR), and the total estimated mass of IC 10. We assume a dark matter halo for this galaxy and study the development of a galactic wind. We consider different star formation regimes: bursting and continuous. We explore different wind situations: i) normal wind, where all the gas is lost at the same rate and ii) metal-enhanced wind, where metals produced by supernovae are preferentially lost. We study a case without wind. We vary the star formation efficiency (SFE), the wind efficiency, and the time scale of the gas infall, which are the most important parameters in our models. Results. We find that only models with metal-enhanced galactic winds can reproduce the properties of IC 10. The star formation must have proceeded in bursts rather than continuously and the bursts must have been less numerous than ~10 over the whole galactic lifetime. Finally, IC 10 must have formed by a slow process of gas accretion with a timescale of the order of 8 Gyr.
By means of a detailed chemical evolution model, we follow the evolution of barium (Ba) and europium (Eu) in four Local Group Dwarf Spheroidal (dSph) galaxies, in order to set constraints on the ...nucleosynthesis of these elements and on the evolution of this type of galaxies compared with the Milky Way. The model, which is able to reproduce several observed abundance ratios and the present-day total mass and gas mass content of these galaxies, adopts up-to-date nucleosynthesis and takes into account the role played by supernovae (SNe) of different types (II, Ia) allowing us to follow in detail the evolution of several chemical elements (H, D, He, C, N, O, Mg, Si, S, Ca, Fe, Ba and Eu). By assuming that Ba is a neutron-capture element produced in low-mass asymptotic giant branch stars by s-process but also in massive stars (in the mass range 10–30 M⊙) by r-process, during the explosive event of SNe of Type II, and that Eu is a pure r-process element synthesized in massive stars also in the range of masses 10–30 M⊙, we are able to reproduce the observed Ba/Fe and Eu/Fe as functions of Fe/H in all four galaxies studied. We confirm also the important role played by the very low star formation (SF) efficiencies (ν= 0.005–0.5 Gyr−1) and by the intense galactic winds (6–13 times the star formation rate) in the evolution of these galaxies. These low SF efficiencies (compared to the one for the Milky Way disc) adopted for the dSph galaxies are the main reason for the differences between the trends of Ba/Fe and Eu/Fe predicted and observed in these galaxies and in the metal-poor stars of our Galaxy. Finally, we provide predictions for Sagittarius galaxy for which data of only two stars are available.
Adaptive responses of skeletal muscle regulate the nuclear shuttling of the sarcomeric protein Ankrd2 that can transduce different stimuli into specific adaptations by interacting with both ...structural and regulatory proteins. In a genome-wide expression study on Ankrd2-knockout or -overexpressing primary proliferating or differentiating myoblasts, we found an inverse correlation between Ankrd2 levels and the expression of proinflammatory genes and identified Ankrd2 as a potent repressor of inflammatory responses through direct interaction with the NF-κB repressor subunit p50. In particular, we identified Gsk3β as a novel direct target of the p50/Ankrd2 repressosome dimer and found that the recruitment of p50 by Ankrd2 is dependent on Akt2-mediated phosphorylation of Ankrd2 upon oxidative stress during myogenic differentiation. Surprisingly, the absence of Ankrd2 in slow muscle negatively affected the expression of cytokines and key calcineurin-dependent genes associated with the slow-twitch muscle program. Thus, our findings support a model in which alterations in Ankrd2 protein and phosphorylation levels modulate the balance between physiological and pathological inflammatory responses in muscle.
BACKGROUND: Glioblastoma (GBM) is a primary malignant brain tumor and its evolution is generally rapidly fatal. The current standard of care for this disease is surgical resection followed by ...concomitant radiationtherapy plus chemiotherapy as described by Stupp and Colleagues. In this study we described our experience in a series of 100 consecutive patients affected by GBM treated with modified Stupp regimen at "Fondazione IRCCS Ca' Granda Ospedale Policlinico Maggiore" in Milan, Italy. METHODS: One hundred patients with newly diagnosed, histologically confirmed GBM were submitted to concomitant chemo-radiation therapy. Subjects who were not able to complete the concomitant phase of chemo-radiation therapy were excluded from this study.The diagnosis was obtained after surgical resection or stereotactic biopsy and then all the patients were treated with radiationtherapy plus continuous daily temozolomide (TMZ) according to a modified Stupp's schedule. In the adjuvant phase we administered a modified schedule consisting of 150mg/mq of TMZ, from day 1 to 5 and 75 mg/mq of TMZ from day 6 to 10 for 12 cycles instead of the 6 standard cycles proposed by Stupp and Colleagues. At recurrence, various strategies were chosen according the patients clinical and radiological status. After the concomitant phase, patients underwent a regular follow-up with a clinical examination and a brain MRI with gadolinium every 3 months. MGMT status was assessed according the method described by Hegi et al. in 2005 and was retrospectively re-evaluated with PCR real time (Pyromark Q96ID System). RESULTS: One hundred patients affected by GBM were included (60 males; 40 females; median age 61). The median KPS at presentation was 70 (range= 40- 100) which remained stable after 6 months. Median Ki67 was 10%. In 63 patients MGMT was methylated (38 males; 25 females. Median TTP-1 was of 12 months) and in 32 patients were MGMT un-methylated (male 21; females11; median TTP-1 of 9 months); in 5 cases we have no data. Surgical resection was done in 92 patients whereas only in 8 cases weproceeded with stereotactic biopsy alone. Gross total resection (>95%) was achieved in 57 patients; while 35 patients receibed a sub-total resection (85-95%).Median Overall survival (OS) was 16 months and TTP-1 and time to tumor progression after recurrence (TTP-2) was 11 months in MGMT methylated patients and 4 months in MGMT un-methylated patients. At a median follow up of 12 months, 24 months and 36 months our OS was 81%, 33% and 20% respectively compared to the historical group described by Stupp in 2005 which were 61% at 12 months and 27.5% at 24 months and 16% at 36 months. Data about the comparison of MGMT status assessment will be discussed at the time of the meeting. CONCLUSION: According the data collected, our modified adjuvant schedule can be useful for increasing the therapeutic effect of TMZ and can contribute to prolong the TTP.
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