150 research outputs found

    Hot Jupiters accreting onto their parent stars: effects on the stellar activity

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    Hot Jupiters (HJs) are massive gaseous planets orbiting close to their host stars. Due to their physical characteristics and proximity to the central star, HJs are the natural laboratories to study the process of star-planet interaction (SPI). Phenomena related to SPI may include the inflation and the evaporation of planetary atmospheres, the formation of cometary tails and bow shocks and magnetospheric interaction between the magnetic field of the planet and that of the star. Several works suggest that some systems show enhanced stellar activity in phase with the planetary rotation period. In this work, we use a 3D magneto-hydrodynamic model that describes a system composed of a star and an HJ and that includes the corresponding planetary and stellar winds. The aim is to investigate whether the material evaporating from the planet interacts with the stellar extended corona, and generates observable features. Our simulation shows that, in some conditions, the planetary wind expands and propagates mainly along the planetary orbit. Moreover, part of the planetary wind collides with the stellar wind and a fraction of the planet's outflow is funnelled by the stellar magnetic field and hits the stellar surface. In both events, the material is heated up to temperatures of a few MK by a shock. These phenomena could manifest in the form of enhanced stellar activity at some orbital phases of the planet.Comment: Accepted for publication in Astronomische Nachrichten - Astronomical Note

    In Vitro Evaluation of Cytotoxicity and Proliferative Effects of Lyophilized Porcine Liver Tissue on HepG2 Hepatoma Cells and Adipose-Tissue-Derived Mesenchymal Stromal Cells

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    In recent years, nutritional supplements from different sources have been widely considered to support medical treatments in patients affected by chronic hepatopathies. Their potential therapeutic benefit has been recognized, but some evidence of safety issues has been reported. Recently it has been hypothesized that the liver could produce various of bioactive factors to maintain organ homeostasis and promote tissue healing. Thus, liver-specific preparations containing bioactive factors could provide a suitable substrate for in vitro study of liver tissue maintenance/healing, as a prospective regenerative medicine approach. Furthermore, they could represent a dietary supplement or nutraceutical for adjuvant therapies when correctly prepared and formulated. This work aims to provide data about the safety and biological activity of a freeze-dried porcine liver preparation. The lyophilized powder obtained from the whole organ has been tested in term of in vitro cell cytotoxicity (MTT assay) and proliferation assays (bromo-deoxyuridine incorporation and direct cell count) in two different cell types: human hepatoma HepG2 cell line and adipose-tissue-derived canine mesenchymal stromal cells (At-MSCs). At concentration levels between 100 to 500 g/mL, the lyophilized liver powder stimulated mitochondrial metabolism as assessed by MTT assay (p 0.001 for HepG2 and for At-MSCs) and induced an increase in bromo-deoxyuridine incorporation in both cell types (p 0.01 for HepG2 and p < 0.001 for At-MSCs). In addition, direct cell count demonstrated a higher proliferative activity in treated At-MSCs (p < 0.001). Although preliminary, these data suggest that the whole-liver powder is noncytotoxic in vitro and may represent a stimulus to cell metabolism and proliferation. Further studies are needed to detect the bioactive components of the supplement and characterize in deeper detail the cellular pathways that they can modulate

    Traumatic Isolated Intramural Duodenal Hematoma Causing Intestinal Obstruction

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    A 21-year-old man was admitted 36 hours after a blunt abdominal trauma occurred during a sporting competition. He complained of colic epigastric abdominal pain, nausea, and vomiting. He was hemodynamically stable; blood counts and metabolic panel were normal. Abdominal CT showed an intestinal obstruction caused by an 8 × 6 × 11 cm hematoma on the right lateral duodenal wall without signs of active bleedin

    Predictors of Central Compartment Involvement in Patients with Positive Lateral Cervical Lymph Nodes According to Clinical and/or Ultrasound Evaluation

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    Lymph node neck metastases are frequent in papillary thyroid carcinoma (PTC). Current guidelines state, on a weak level of evidence, that level VI dissection is mandatory in the presence of latero-cervical metastases. The aim of our study is to evaluate predictive factors for the absence of level VI involvement despite the presence of metastases to the lateral cervical stations in PTC. Eighty-eight patients operated for PTC with level II-V metastases were retrospectively enrolled in the study. Demographics, thyroid function, autoimmunity, nodule size and site, cancer variant, multifocality, Bethesda and EU-TIRADS, number of central and lateral lymph nodes removed, number of positive lymph nodes and outcome were recorded. At univariate analysis, PTC location and number of positive lateral lymph nodes were risk criteria for failure to cure. ROC curves demonstrated the association of the number of positive lateral lymph nodes and failure to cure. On multivariate analysis, the protective factors were PTC located in lobe center and number of positive lateral lymph nodes &lt; 4. Kaplan-Meier curves confirmed the absence of central lymph nodes as a positive prognostic factor. In the selected cases, Central Neck Dissection (CND) could be avoided even in the presence of positive Lateralcervical Lymph Nodes (LLN+)

    Extracorporeal shock waves alone or combined with raloxifene promote bone formation and suppress resorption in ovariectomized rats

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    Osteoporosis is a metabolic skeletal disease characterized by an imbalance between osteoclast-mediated bone resorption and osteoblast-mediated bone formation. We examined the beneficial effect of shock waves (SW) alone or in combination with raloxifene (RAL) on bone loss in ovariectomized rats (OVX). Sixteen weeks after surgery, OVX were treated for five weeks with SW at the antero-lateral side of the right hind leg, one session weekly, at 3 Hz (EFD of 0.33 mJ/mm2), or with RAL (5 mg/kg/die, per os) or with SW+RAL. Sera, femurs, tibiae and vertebrae were sampled for following biochemical and histological analysis. SW, alone or combined with RAL, prevented femur weight reduction and the deterioration of trabecular microarchitecture both in femur and vertebrae. All treatments increased Speed of Sound (SoS) values, improving bone mineral density, altered by OVX. Serum parameters involved in bone remodeling (alkaline phosphatase, receptor activator of nuclear factor kappa-B ligand, osteoprotegerin) and osteoblast proliferation (PTH), altered by ovariectomy, were restored by SW and RAL alone or in combination. In tibiae, SW+RAL significantly reduced cathepsin k and TNF-α levels, indicating the inhibition of osteoclast activity, while all treatments significantly increased runt-related transcription factor 2 and bone morphogenetic-2 expression, suggesting an increase in osteoblastogenic activity. Finally, in bone marrow from tibiae, SW or RAL reduced PPARγ and adiponectin transcription, indicating a shift of mesenchymal cells toward osteoblastogenesis, without showing a synergistic effect. Our data indicate SW therapy, alone and in combination with raloxifene, as an innovative strategy to limit the hypoestrogenic bone loss, restoring the balance between bone formation and resorption

    Effects of a Lactobacillus paracasei B21060 based synbiotic on steatosis, insulin signaling and toll-like receptor expression in rats fed a high-fat diet.

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    Insulin resistance (IR) has been identified as crucial pathophysiological factor in the development and progression of non-alcoholic fatty liver disease (NAFLD). Although mounting evidence suggests that perturbation of gut microflora exacerbates the severity of chronic liver diseases, therapeutic approaches using synbiotic has remained overlooked. Here, we show that a synbiotic composed by Lactobacillus paracasei B21060 plus arabinogalactan and fructo-oligosaccharides lessens NAFLD progression in a rat model of high fat feeding. IR and steatosis were induced by administration of high fat diet (HFD) for 6 weeks. Steatosis and hepatic inflammation, Toll-like receptor (TLR) pattern, glucose tolerance, insulin signaling and gut permeability were studied. Liver inflammatory markers were down-regulated in rats receiving the synbiotic, along with an increased expression of nuclear peroxisome proliferator-activated receptors and expression of downstream target genes. The synbiotic improved many aspects of IR, such as fasting response, hormonal homeostasis and glycemic control. Indeed it prevented the impairment of hepatic insulin signaling, reducing the phosphorylation of insulin receptor substrate-1 in Ser 307 and down-regulating suppressor of cytokine signaling 3. Gene expression analysis revealed that in the liver the synbiotic reduced cytokines synthesis and restored the HFD-dysregulated TLR 2, 4 and 9 mRNAs toward a physiological level of expression. The synbiotic preserved gut barrier integrity and reduced the relative amount of Gram-negative Enterobacteriales and Escherichia coli in colonic mucosa. Overall, our data indicate that the L. paracasei B21060 based synbiotic is effective in reducing the severity of liver injury and IR associated with high fat intake, suggesting its possible therapeutic/preventive clinical utilization

    High Prevalence of Arcobacter Carriage in Older Subjects with Type 2 Diabetes

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    Arcobacters are potential pathogens related to diarrheic infections and, rarely, septicaemia. This study evaluated the prevalence of arcobacters in stool samples of subjects with (n = 38) and without (n = 61) type 2 diabetes by using cultural and molecular techniques. Three Arcobacter positive cultures were found, all among diabetic subjects, whereas molecular analysis showed a carriage rate of 79% and 26.2% in subjects with and without type 2 diabetes (P < .001), respectively. The multivariate analysis showed that type 2 diabetes (β = 1.913; 95%CI: 2.378–19.285; P < .0001) and age (β = 1.744; 95%CI: 2.077–15.766; P = .001) were the only factors independently associated with arcobacters colonization in this population. Our study demonstrated a high prevalence of arcobacters colonization in type 2 diabetic and older subjects. The clinical significance and the potential health risk associated with these emerging species remain to be determined

    Isolated auditory neuropathy at birth in congenital cytomegalovirus infection

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    BACKGROUND: Congenital cytomegalovirus (cCMV) infection is the most frequent non-genetic cause of sensorineural hearing-loss (SNHL) (i.e., hearing loss due to a cochlear and/or auditory nerve damage). It is widely accepted that SNHL at birth, when associated to cCMV symptomatic infection involving the central nervous system, benefits from antiviral therapy started in the neonatal period. Conversely, there is no consensus for antiviral treatment in congenitally infected infants diagnosed with isolated SNHL (i.e., SNHL in an otherwise asymptomatic infant) at birth. Our aim was to assess the frequency and the auditory outcome of isolated SNHL at birth due to auditory neuropathy (AN) (i.e., SNHL in a patient with normal cochlear function and auditory nerve dysfunction) in infants with cCMV infection. METHODS: We retrospectively reviewed the clinical history of 60 infants, born at term, with cCMV asymptomatic infection, without additional risk factors for SNHL, and exhibiting bilateral "pass" otoacustic emissions (OAE). None of them underwent antiviral therapy. Hearing thresholds were assessed by means of Auditory Brainstem Responses (ABR). AN affected children were followed up until possible normalization of the hearing thresholds or definitive diagnosis of AN. Each infant diagnosed with monolateral or bilateral AN was classified according to the worst ear threshold. RESULTS: In our population, the first ABR was performed at a mean age of 5.00 ± 2.79 (SD) months and AN was diagnosed in 16/60 (26.67%) infants; in 4 infants the AN was defined as mild (4/4 monolateral), moderate in 11 (5/11 bilateral), and severe in 1 (bilateral). The mean age at first ABR was 3.69 ± 2.80 (SD) months in the 16 babies with AN and 5.48 ± 2.66 (SD) months in the 44 infants with normal hearing (p = 0.007). All AN cases spontaneously recovered a normal auditory threshold over time. The mean length of the audiological follow-up was 32.44 ± 17.58 (SD) months (range 5-60 months). CONCLUSION: A delayed maturation of the auditory pathways should be considered when a mild/moderate isolated AN at birth is detected in cCMV infected infants. Prospective studies conducted on larger populations, and with a longer audiological follow-up, are needed to confirm our findings
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