Dark matter halo cores and the tidal survival of Milky Way satellites

The cuspy central density profiles of cold dark matter (CDM) haloes make them highly resilient to disruption by tides. Self-interactions between dark matter particles, or the cycling of baryons during galaxy formation, may result in the formation of a constant density core which would make haloes more susceptible to tidal disruption. We use N-body simulations to study the evolution of NFW-like "cored" subhaloes in the tidal field of a massive host, and identify the criteria and timescales for full tidal disruption. Applied to the Milky Way (MW), our results imply that the survival of MW satellites places interesting constraints on core formation. Indeed, we find that no subhaloes with cores larger than 1 per cent of their initial NFW scale radius can survive for a Hubble time on orbits with pericentres <10 kpc. A satellite like Tucana 3, with pericentre ~3.5 kpc, must have a core size smaller than ~2 pc to survive just three orbital periods on its current orbit. The core sizes expected in self-interacting dark matter (SIDM) models with a velocity-independent cross section of 1 cm^2/g seem incompatible with ultra-faint satellites with small pericentric radii, such as Tuc 3, Seg 1, Seg 2, Wil 1, as these would fully disrupt in less than 10 Gyr after infall. These results suggest that many satellites have vanishingly small core sizes, consistent with CDM cusps. The discovery of further Milky Way satellites on orbits with small pericentric radii would strengthen these conclusions and allow for stricter upper limits on the core sizes implied by the survival of Milky Way satellites.Comment: 13 pages, 13 figures, submitted to MNRAS, comments welcom

Viral nervous necrosis outbreaks caused by the RGNNV/SJNNV reassortant betanodavirus in gilthead sea bream (Sparus aurata) and European sea bass (Dicentrarchus labrax)

Mediterranean marine aquaculture has suffered significant economic losses due to viral nervous necrosis (VNN) outbreaks mainly caused by different RGNNV betanodavirus strains. In recent years, the marine aquaculture sector has experienced the emergence of the RGNNV/SJNNV reassortant betanodavirus, harbouring the RNA1 segment of RGNNV genotype and the RNA2 segment of SJNNV genotype. So far, the reassortant strains caused massive mortality outbreaks in gilthead sea bream (Sparus aurata) larvae sparing the European sea bass (Dicentrarchus labrax). In this study, multiple mortality outbreaks occurred in one Italian marine hatchery involving both European sea bass and gilthead sea bream at different life stages were investigated through a complete microbiological and molecular analysis. Gilthead sea bream larvae and juveniles have recorded the highest mortality rates, however, both European sea bass and gilthead sea bream incurred a RGNNV/SJNNV reassortant betanodavirus persistent infection, able to act as asymptomatic carriers and viral source for susceptible fish. These new epidemiological data on nervous necrosis virus (NNV) reassortant infection provide precious advice on how to manage fish to reduce VNN spread in Mediterranean aquaculture. Evidence of interspecies transmission of RGNNV/SJNNV reassortant strains and the persistent infection in both European sea bass and gilthead sea bream, point out the importance to enforce a wide surveillance and a strict biosecurity programme addressing both RGNNV and reassortant RGNNV/SJNNV betanodaviruses in Mediterranean European sea bass and gilthead sea bream farms. Furthermore, the presence assessment of betanoviruses in all newly-introduced fish batches in the farm, regardless of the species and a strict segregation between European sea bass and gilthead sea bream batches within farms can significantly reduce the risk of NNV transmission. Finally, surviving fish can act as carrier fish, and thereby must be segregated from other batches and protected from stress conditions that could trigger a new clinical phase

Micro galaxies as a falsifiable prediction of LCDM cosmology

A fundamental prediction of the Lambda Cold Dark Matter (LCDM) cosmology are the centrally-divergent cuspy density profiles of dark matter haloes. These density cusps render CDM haloes resilient to tides, and protect dwarf galaxies embedded in them from full tidal disruption. The hierarchical assembly history of the Milky Way may therefore give rise to a population of "micro galaxies"; i.e., heavily-stripped remnants of early accreted satellites which may reach arbitrarily low luminosity. Assuming that the progenitor systems are dark matter dominated, we use an empirical formalism for tidal stripping to predict the evolution of the luminosity, size and velocity dispersion of such remnants, tracing their tidal evolution across multiple orders of magnitude in mass and size. The evolutionary tracks depend sensitively on the progenitor distribution of stellar binding energies. We explore two cases that likely bracket most realistic models of dwarf galaxies: one where the energy distribution of the most tightly bound stars follows that of the dark matter, and another where stars are less tightly bound and have a well-defined finite density core. The tidal evolution in the size-velocity dispersion plane is quite similar for these two models, although their remnants may differ widely in luminosity. Micro galaxies are therefore best distinguished from globular clusters by the presence of dark matter; either directly, by measuring their velocity dispersion, or indirectly, by examining their tidal resilience. Our work highlights the need for further theoretical and observational constraints on the stellar energy distribution in dwarf galaxies.Comment: submitted to ApJ, comments welcom

Disseminated phaeohyphomycosis in a beluga sturgeon (Huso huso)

Phaeohyphomycosis is a fungal infection caused by dematiaceous or melanised fungi (Seyedmousavi, Guillot, and de Hoog 2013). Although considered ubiquitous residents of plant material, soil, and wood, melanised fungi are likely adapted to specific niches that facilitate variable opportunistic or true pathogenic potentials. Exposure is typically associated with inoculation by minor trauma or inhalation. In mammals, infections are commonly cutaneous, subcutaneous, upper respiratory or primary cerebral, but in cold-blooded vertebrates are often disseminated and accompanied by severe tissue necrosis (Revankar, Sutton, and Rinaldi 2004; Seyedmousavi, Guillot, and de Hoog 2013)

In Silico Seawater

Many important processes affecting the Earth's climate are determined by the physical properties of seawater. Desalination of seawater is a significant source of drinking wate.Since the physical properties of seawater governing these processes depend on the molecular interactions among its components, a deeper knowledge of seawater at the molecular level is needed. However MD studies reporting the physical properties of seawater are currently lacking. This is probably due to the usual perception of the seawater composition being too complex to approach.This point of view ignores the fact that physical properties of seawater are dependent on a single parameter representing the composition, namely the salinity. This is because the relative proportions of any two major constituents of seasalt are always the same. An obstacle to performing MD simulations of seawater could have been the unavailability of a satisfactory force field representing the interactions between water molecules and dissolved substances. This drawback has recently been overcome with the proposal of the Madrid-2019 FF.Here we show for the first time that MD simulations of seawater are feasible. We have performed MD simulations of a system, the composition of which is close to the average composition of standard seawater and with the molecular interactions given by the Madrid-2019 force field. We are able to provide quantitative or semiquantitative predictions for a number of relevant physical properties of seawater for temperatures and salinities from the oceanographic range to those relevant to desalination processes. The computed magnitudes include static (density), dynamical (viscosity and diffusion coefficients), structural (ionic hydration, ion-ion distribution functions) and interfacial (surface tension) properties

Immunohistochemical evaluation of bone metastases

  Introduction. Metastases are the most common type of malignancy involving the bone, while bone is the third most frequent site for metastases, after the lung and liver. In some patients, medical history, physical and laboratory exami­nation are not conclusive to identify the primary tumor site. In such cases a bone biopsy and immunohistochemical analysis may contribute to the diagnosis, determination of appropriate treatment and evaluation of prognosis. In this study, we tried to evaluate the imunochistochemical expression in bone metastases. Material and methods. We reviewed 125 patients, with a mean age of 63 years, treated for bone metastases in our institution. All patients received palliative orthopaedic surgery for bone metastatic carcinoma. Fifty-eight patients had already an established diagnosis of the primary tumor, while 67 patients presented metastases with an unknown primary tumor origin. Immunohistochemical analysis was performed to intra-operative bone biopsy specimens. The expression of cytokeratine 7, cytokeratin 20 and the expression of a panel of other organ-specific markers were re­corded. In patients with a known primary tumor, we examined the relationship between the origin of metastases, as suggested by the cytokeratin phenotype, compared with the one indicated by the initial histological diagnosis. We also recorded the efficacy of organ-specific markers to identify the primary tumor origin in epithelial bone metastases and we evaluated the prognosis between patients with a immunohistologically determined primary tumor origin, with those with an undetermined one. Results. Associations of cytokeratine 7 and cytokeratine 20 expression confirmed diagnosis in 51 out of the 58 patients (88%) with a known primary tumor (Cohen’s K test 0.79 SE 0.80, P &lt; 0.0005). Immunohistochemical analysis also contributed to establish the diagnosis of patients with an unknown primary tumor, yielding diagnosis in 35 out of the 67 cases (52%). Patients with an immunochistologically undetermined primary tumor site presented a statisti­cally significant poorer prognosis. Conclusions. Cytokeratine 7 and cytokeratine20 are useful immunochistochemical markers in determining a pre­liminary evaluation of bone metastases. Organ-specific immunohistochemical markers have a reliable role in either suggesting or confirming the possible origin of metastases. An indeterminate immunohistochemical phenotype seems to relate to a less differentiated lesion, with a worse prognosis

Risk factors of fracture following curettage for bone giant cell tumors of the extremities

Background: Following curettage of giant cell tumor of bone (GCTB), it is common to fill the cavity with polymethylmethacrylate (PMMA) bone cement, bone allograft, or artificial bone to maintain bone strength; however, there is a 2–14% risk of postoperative fractures. We conducted this retrospective study to clarify the risk factors for fractures after curettage for GCTB of the extremities. Methods: This study included 284 patients with GCTBs of the extremities who underwent curettage at our institutions between 1980 and 2018 after excluding patients whose cavities were not filled with anything or who had additional plate fixation. The tumor cavity was filled with PMMA bone cement alone (n =&nbsp;124), PMMA bone cement and bone allograft (n =&nbsp;81), bone allograft alone (n =&nbsp;63), or hydroxyapatite graft alone (n =&nbsp;16). Results: Fractures after curettage occurred in 10 (3.5%) patients, and the median time from the curettage to fracture was 3.5 months (interquartile range [IQR], 1.8–8.3 months). The median postoperative follow-up period was 86.5 months (IQR, 50.3–118.8 months). On univariate analysis, patients who had GCTB of the proximal or distal femur (1-year fracture-free survival, 92.5%; 95% confidence interval [CI]: 85.8–96.2) presented a higher risk for postoperative fracture than those who had GCTB at another site (100%; p = 0.0005). Patients with a pathological fracture at presentation (1-year fracture-free survival, 88.2%; 95% CI: 63.2–97.0) presented a higher risk for postoperative fracture than those without a pathological fracture at presentation (97.8%; 95% CI: 95.1–99.0; p = 0.048). Patients who received bone grafting (1-year fracture-free survival, 99.4%; 95% CI: 95.7–99.9) had a lower risk of postoperative fracture than those who did not receive bone grafting (94.4%; 95% CI: 88.7–97.3; p = 0.003). Conclusions: For GCTBs of the femur, especially those with pathological fracture at presentation, bone grafting after curettage is recommended to reduce the risk of postoperative fracture. Additional plate fixation should be considered when curettage and cement filling without bone grafting are performed in patients with GCTB of the femur. This should be specially performed for those patients with a pathological fracture at presentation

Immunohistochemical evaluation of bone metastases

  Introduction. Metastases are the most common type of malignancy involving the bone, while bone is the third most frequent site for metastases, after the lung and liver. In some patients, previous medical history, physical and laboratory examination are not conclusive to identify the primary tumor site. In such cases a bone biopsy and im­munohistochemical analysis may contribute to the diagnosis, determination of appropriate treatment and evaluation of prognosis. In this study, we tried to evaluate the imunochistochemical expression in bone metastases. Material and methods. We reviewed 125 patients, with a mean age of 63 years, treated for bone metastases in our institution. All patients received palliative orthopaedic surgery for bone metastatic carcinoma. Fifty-eight patients had already an established diagnosis of the primary tumor, while 67 patients presented metastases with an unknown primary tumor origin. Immunohistochemical analysis was performed to intra-operative bone biopsy specimens. The expression of cytokeratine 7, cytokeratin 20 and the expression of a panel of other organ-specific markers were re­corded. In patients with a known primary tumor, we examined the relationship between the origin of metastases, as suggested by the cytokeratin phenotype, compared with the one indicated by the initial histological diagnosis. We also recorded the efficacy of organ-specific markers to identify the primary tumor origin in epithelial bone metastases and we evaluated the prognosis between patients with a immunohistologically determined primary tumor origin, with those with an undetermined one. Results. Associations of cytokeratine 7 and cytokeratine 20 expression confirmed diagnosis in 51 out of the 58 patients (88%) with a known primary tumor (Cohen’s K test 0.79 SE 0.80, P &lt; 0.0005). Immunohistochemical analysis also contributed to establish the diagnosis of patients with an unknown primary tumor, yielding diagnosis in 35 out of the 67 cases (52%). Patients with an immunochistologically undetermined primary tumor site presented a statisti­cally significant poorer prognosis. Conclusions. Cytokeratine 7 and cytokeratine20 are useful immunochistochemical markers in determining a pre­liminary evaluation of bone metastases. Organ-specific immunohistochemical markers have a reliable role in either suggesting or confirming the possible origin of metastases. An indeterminate immunohistochemical phenotype seems to relate to a less differentiated lesion, with a worse prognosis. Introduction. Metastases are the most common type of malignancy involving the bone, while bone is the third most frequent site for metastases, after the lung and liver. In some patients, previous medical history, physical and laboratory examination are not conclusive to identify the primary tumor site. In such cases a bone biopsy and im­munohistochemical analysis may contribute to the diagnosis, determination of appropriate treatment and evaluation of prognosis. In this study, we tried to evaluate the imunochistochemical expression in bone metastases. Material and methods. We reviewed 125 patients, with a mean age of 63 years, treated for bone metastases in our institution. All patients received palliative orthopaedic surgery for bone metastatic carcinoma. Fifty-eight patients had already an established diagnosis of the primary tumor, while 67 patients presented metastases with an unknown primary tumor origin. Immunohistochemical analysis was performed to intra-operative bone biopsy specimens. The expression of cytokeratine 7, cytokeratin 20 and the expression of a panel of other organ-specific markers were re­corded. In patients with a known primary tumor, we examined the relationship between the origin of metastases, as suggested by the cytokeratin phenotype, compared with the one indicated by the initial histological diagnosis. We also recorded the efficacy of organ-specific markers to identify the primary tumor origin in epithelial bone metastases and we evaluated the prognosis between patients with a immunohistologically determined primary tumor origin, with those with an undetermined one. Results. Associations of cytokeratine 7 and cytokeratine 20 expression confirmed diagnosis in 51 out of the 58 patients (88%) with a known primary tumor (Cohen’s K test 0.79 SE 0.80, P &lt; 0.0005). Immunohistochemical analysis also contributed to establish the diagnosis of patients with an unknown primary tumor, yielding diagnosis in 35 out of the 67 cases (52%). Patients with an immunochistologically undetermined primary tumor site presented a statisti­cally significant poorer prognosis. Conclusions. Cytokeratine 7 and cytokeratine20 are useful immunochistochemical markers in determining a pre­liminary evaluation of bone metastases. Organ-specific immunohistochemical markers have a reliable role in either suggesting or confirming the possible origin of metastases. An indeterminate immunohistochemical phenotype seems to relate to a less differentiated lesion, with a worse prognosis

Bone Targeting Agents in Patients with Prostate Cancer: General Toxicities and Osteonecrosis of the Jaw

Introduction: Bone metastases are the most frequent site of secondary localization of prostate cancer (PCa) and are present in about 90% of cases of advanced disease. Consequently, an ade-quate management of bone involvement is of pivotal importance in the therapeutic approach and skeletal-related events (SREs) need to be closely monitored and promptly assessed and treated. Bone targeting agents (BTAs), consisting in bisphosphonates and denosumab, are an essential part of the treatment of metastatic prostate cancer that accompanies systemic treatments throughout the most part of the history of the disease. Activity and safety of bone targeting agents: These treatments are correlated to better outcomes in terms of reduction of SREs and, in metastatic castration resistant setting, of increased overall survival (OS), but several important adverse events have to be managed and prevented. Of these, osteonecrosis of the jaw (ONJ) is extremely invalidating and should be managed with a special attention. Discussion: The role of BTAs in prostate cancer is pivotal throughout many stages of the disease, but several toxicities should be quickly recognized and treated. We aim at recollecting evidence on clinical benefit of BTAs, common and specific toxicities, and explore the pathophysiology and clinical aspects of osteonecrosis of the jaw. We present a review of the literature to report the role of the different types of bone targeting agents in the management of prostate cancer with bone metastases with a particular focus on common toxicities and ONJ to rec-ollect current evidences on the activity of these compounds and the correct management of their adverse events