Analisi critica della superconduttività BCS in relazione all'effetto Meissner

In questa tesi vengono analizzati i principali argomenti con cui il fisico argentino J.E. Hirsch critica la descrizione dell' effetto Meissner nella teoria della superconduttività BCS. Hirsch afferma che la spiegazione dell' effetto Meissner nel framework tradizionale sia incompatibile con la conservazione del momento angolare e con la reversibilità della transizione superconduttiva, e propone una teoria alternativa, chiamata hole superconductivity, che sarebbe in grado di fornire una descrizione soddisfacente di questi fenomeni. Nel primo capitolo sono riportati i principali risultati ottenuti dalla teoria BCS. Nel secondo capitolo si espongono le argomentazioni critiche mosse da Hirsch. In particolare, quando la transizione superconduttiva avviene in presenza di un campo magnetico costante, Hirsch sostiene che la teoria BCS non contenga al suo interno gli elementi fisici in grado di generare la corrente di Meissner che scherma il campo, e di giustificare la reversibilità della transizione. Nel terzo capitolo viene proposto il meccanismo della hole superconductivity che, secondo Hirsch, è in grado di spiegare in modo consistente tali fenomeni. Vengono affrontati solo gli aspetti della hole superconductivity inerenti alla critica mossa da Hirsch, non viene trattata la teoria nella sua interezza

Comparison between X-ray-hysterosalpingography and 3 Tesla magnetic resonance-hysterosalpingography in the assessment of the tubal patency in the cause of female infertility

Objectives XR-hysterosalpingography currently represents the gold standard for tubal pathology evaluation. Magnetic resonance-HSG is an innovative technique. With our study, we aim to comprehend if and how MR-HSG, compared to traditional XR-HSG, could give us this additional information in the diagnostic/therapeutic process. Materials and methods This study included 19 patients between 30 and 42 years old (average age 37.7) affected by infertility. Patients underwent contextually both XR-HSG and MR-HSG, using a single catheterization. The dynamic MR-HSG exam consisted a MR sequence during contrast administration through the cervical catheter. Results Both XR-HSG and MR-HSG documented that 15 of the 19 patients had bilateral tubal patency, while four patients had monolateral tubal patency. However, MR-HSG allowed us to diagnose additional findings: Two active endometriosis foci in adnexal localization and a condition of adenomyosis A unicornuate uterus malformation A submucous uterine myoma near the tubal ostium A decrease of the ovarian reserve in a patient So MR-HSG could potentially detect in 10/19 (52%) women the cause of their infertility, compared to 4/19 (21%) detected with XR-HSG and about 30% of women would have resulted as false negatives if we only used XR-HSG. Finally, with a questionnaire, we demonstrated that MR-HSG is less painful than XR-HSG. Conclusions These data thus confirm that XR-HSG and MR-HSG present the same diagnostic of assessing tubal patency. We also demonstrated that MR-HSG is able to detect further collateral findings that could likewise be a possible therapeutic target and it could possibly become the new gold standard in female infertility diagnostics

Simulated microgravity promotes the formation of tridimensional cultures and stimulates pluripotency and a glycolytic metabolism in human hepatic and biliary tree stem/progenitor cells

Many pivotal biological cell processes are affected by gravity. The aim of our study was to evaluate biological and functional effects, differentiation potential and exo-metabolome profile of simulated microgravity (SMG) on human hepatic cell line (HepG2) and human biliary tree stem/progenitor cells (hBTSCs). Both hBTSCs and HepG2 were cultured in a weightless and protected environment SGM produced by the Rotary Cell Culture System (Synthecon) and control condition in normal gravity (NG). Self-replication and differentiation toward mature cells were determined by culturing hBTSCs in Kubota's Medium (KM) and in hormonally defined medium (HDM) tailored for hepatocyte differentiation. The effects on the expression and cell exo-metabolome profiles of SMG versus NG cultures were analyzed. SMG promotes tridimensional (3D) cultures of hBTSCs and HepG2. Significative increase of stemness gene expression (p < 0.05) has been observed in hBTSCs cultured in SMG when compared to NG condition. At the same time, the expression of hepatocyte lineage markers in hBTSCs differentiated by HDM was significantly lower (p < 0.05) in SMG compared to NG, demonstrating an impaired capability of hBTSCs to differentiate in vitro toward mature hepatocytes when cultured in SMG condition. Furthermore, in HepG2 cells the SMG caused a lower (p < 0.05 vs controls) transcription of CYP3A4, a marker of late-stage (i.e. Zone 3) hepatocytes. Exo-metabolome NMR-analysis showed that both cell cultures consumed a higher amount of glucose and lower glutamate in SMG respect to NG (p < 0.05). Moreover, hBTSCs media cultures resulted richer of released fermentation (lactate, acetate) and ketogenesis products (B-hydroxybutyrate) in SGM (p < 0.05) than NG. While, HepG2 cells showed higher consumption of amino acids and release of ketoacids (3-Methyl-2-oxovalerate, 2-oxo-4-methyl-valerate) and formiate with respect to normogravity condition (p < 0.05). Based on our results, SMG could be helpful for developing hBTSCs-derived liver devices. In conclusion, SMG favored the formation of hBTSCs and HepG2 3D cultures and the maintenance of stemness contrasting cell differentiation; these effects being associated with stimulation of glycolytic metabolism. Interestingly, the impact of SMG on stem cell biology should be taken into consideration for workers involved in space medicine programs

Gli studi di genere in Italia: passato, presente e futuro di una sfida ancora aperta

L'articolo riporta una tavola rotonda sugli studi di genere in Italia da molteplici prospettive

Epigenetic Mechanisms in Gastric Cancer: Potential New Therapeutic Opportunities

: Gastric cancer (GC) is one of the deadliest malignancies worldwide. Complex disease heterogeneity, late diagnosis, and suboptimal therapies result in the poor prognosis of patients. Besides genetic alterations and environmental factors, it has been demonstrated that alterations of the epigenetic machinery guide cancer onset and progression, representing a hallmark of gastric malignancies. Moreover, epigenetic mechanisms undergo an intricate crosstalk, and distinct epigenomic profiles can be shaped under different microenvironmental contexts. In this scenario, targeting epigenetic mechanisms could be an interesting therapeutic strategy to overcome gastric cancer heterogeneity, and the efforts conducted to date are delivering promising results. In this review, we summarize the key epigenetic events involved in gastric cancer development. We conclude with a discussion of new promising epigenetic strategies for gastric cancer treatment

Management of adverse events with tailored sorafenib dosing prolongs survival of hepatocellular carcinoma patients

Sorafenib is associated with multiple adverse events (AEs), potentially causing its permanent interruption. The impact of the physicians experience on the management of these AEs and the relative implications on clinical outcomes are unknown. We verified if the AEs management changed over time and if these modifications impacted on treatment duration and overall survival (OS)

Radiofrequency Ablation of hepatocellular carcinoma: a meta-analysis of overall survival and recurrence-free survival

Background and aims So far, no randomized trial or meta-analysis has been conducted on overall survival (OS) and recurrence-free survival (RFS) factors in patients treated with radiofrequency ablation (RFA) alone. The purpose of this meta-analysis was to evaluate prognostic factors of OS and RFS in patients treated with RFA. Methods A primary analysis was planned to evaluate the clinical prognostic factor of OS. RFS was the secondary aim. Thirty-four studies published from 2003 to 2017 were analyzed. They included 11,216 hepatocellular carcinoma patients. Results The results showed that Child\u2013Pugh B vs Child\u2013Pugh A (HR =2.32; 95% CI: 2.201\u20132.69; P&lt;0.0001) and albumin\u2013bilirubin score 1 vs 0 (HR =2.69; 95% CI: 2.10\u20133.44; P&lt;0.0001) were predictive of poor OS. Tumor size as a continuous variable was not predictive of OS, although it was predictive of OS when we considered the size as a cutoff value (.2 cm vs &lt;2 cm: HR =1.41; 95% CI: 1.23\u20131.61; P&lt;0.0001; &gt;3 cm vs &lt;3 cm: HR =1.43; 95% CI: 1.17\u20131.74; P&lt;0.0001) and in presence of &gt;1 nodule (HR =1.59; 95% CI: 1.46\u20131.74; P&lt;0.0001). Alpha-fetoprotein &gt;20 ng/mL (HR =1.46; 95% CI: 1.25\u20131.70; P&lt;0.0001) was the only predictive factor of poor prognosis. Conclusion Our meta-analysis highlighted that the maximum benefit of RFA in terms of OS and RFS is reached in the presence of Child\u2013Pugh A, albumin\u2013bilirubin score 1, single-nodule tumor sized &lt;2 cm, and alpha-fetoprotein &lt;20 ng/mL

In hepatocellular carcinoma miR-221 modulates sorafenib resistance through inhibition of caspase-3\u2013mediated apoptosis

Purpose: The aberrant expression of miR-221 is a hallmark of human cancers, including hepatocellular carcinoma (HCC), and its involvement in drug resistance, together with a proved in vivo efficacy of anti-miR-221 molecules, strengthen its role as an attractive target candidate in the oncologic field. The discovery of biomarkers predicting the response to treatments represents a clinical challenge in the personalized treatment era. This study aimed to investigate the possible role of miR-221 as a circulating biomarker in HCC patients undergoing sorafenib treatment as well as to evaluate its contribution to sorafenib resistance in advanced HCC. Experimental Design: A chemically induced HCC rat model and a xenograft mouse model, together with HCC-derived cell lines were employed to analyze miR-221 modulation by Sorafenib treatment. Data from the functional analysis were validated in tissue samples from surgically resected HCCs. The variation of circulating miR-221 levels in relation to Sorafenib treatment were assayed in the animal models and in two independent cohorts of patients with advanced HCC. Results: MiR-221 over-expression was associated with Sorafenib resistance in two HCC animal models and caspase-3 was identified as its target gene, driving miR-221 anti-apoptotic activity following Sorafenib administration. Lower pre-treatment miR-221 serum levels were found in patients subsequently experiencing response to Sorafenib and an increase of circulating miR-221 at the two months assessment was observed in responder patients. Conclusions: MiR-221 might represent a candidate biomarker of likelihood of response to Sorafenib in HCC patients to be tested in future studies. Caspase-3 modulation by miR-221 participates to Sorafenib resistance