Navier-Stokes-Voigt equations with memory in 3D lacking instantaneous kinematic viscosity

We consider a Navier-Stokes-Voigt fluid model where the instantaneous kinematic viscosity has been completely replaced by a memory term incorporating hereditary effects, in presence of Ekman damping. The dissipative character of our model is weaker than the one where hereditary and instantaneous viscosity coexist, previously studied by Gal and Tachim-Medjo. Nevertheless, we prove the existence of a regular exponential attractor of finite fractal dimension under rather sharp assumptions on the memory kernel.Comment: 26 page

Asymptotics of the Coleman-Gurtin model

This paper is concerned with the integrodifferential equation \partial_t u-\Delta u -\int_0^\infty \kappa(s)\Delta u(t-s)\,\d s + \varphi(u)=f arising in the Coleman-Gurtin's theory of heat conduction with hereditary memory, in presence of a nonlinearity $\varphi$ of critical growth. Rephrasing the equation within the history space framework, we prove the existence of global and exponential attractors of optimal regularity and finite fractal dimension for the related solution semigroup, acting both on the basic weak-energy space and on a more regular phase space.Comment: Accepted in Discrete and Continuous Dynamical Systems, Serie

Efficacy and epigenetic interactions of novel DNA hypomethylating agent guadecitabine (SGI-110) in preclinical models of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a deadly malignancy characterized at the epigenetic level by global DNA hypomethylation and focal hypermethylation on the promoter of tumor suppressor genes. In most cases it develops on a background of liver steatohepatitis, fibrosis, and cirrhosis. Guadecitabine (SGI-110) is a second-generation hypomethylating agent, which inhibits DNA methyltransferases. Guadecitabine is formulated as a dinucleotide of decitabine and deoxyguanosine that is resistant to cytidine deaminase (CDA) degradation and results in prolonged in vivo exposure to decitabine following small volume subcutaneous administration of guadecitabine. Here we found that guadecitabine is an effective demethylating agent and is able to prevent HCC progression in pre-clinical models. In a xenograft HCC HepG2 model, guadecitabine impeded tumor growth and inhibited angiogenesis, while it could not prevent liver fibrosis and inflammation in a mouse model of steatohepatitis. Demethylating efficacy of guadecitabine on LINE-1 elements was found to be the highest 8 d post-infusion in blood samples of mice. Analysis of a panel of human HCC vs. normal tissue revealed a signature of hypermethylated tumor suppressor genes (CDKN1A, CDKN2A, DLEC1, E2F1, GSTP1, OPCML, E2F1, RASSF1, RUNX3, and SOCS1) as detected by methylation-specific PCR. A pronounced demethylating effect of guadecitabine was obtained also in the promoters of a subset of tumor suppressors genes (CDKN2A, DLEC1, and RUNX3) in HepG2 and Huh-7 HCC cells. Finally, we analyzed the role of macroH2A1, a variant of histone H2A, an oncogene upregulated in human cirrhosis/HCC that synergizes with DNA methylation in suppressing tumor suppressor genes, and it prevents the inhibition of cell growth triggered by decitabine in HCC cells. Guadecitabine, in contrast to decitabine, blocked growth in HCC cells overexpressing macroH2A1 histones and with high CDA levels, despite being unable to fully demethylate CDKN2A, RUNX3, and DLEC1 promoters altered by macroH2A1. Collectively, our findings in human and mice models reveal novel epigenetic anti-HCC effects of guadecitabine, which might be effective specifically in advanced states of the disease

Editorial: Gastrointestinal Surgery: Emerging techniques, controversies and state of art

Artificial intelligence; Gastrointestinal surgery; Surgical techniquesInteligencia artificial; Cirugía gastrointestinal; Técnicas quirúrgicasIntel·ligència artificial; Cirurgia gastrointestinal; Tècniques quirúrgique

Evolution of Surgical Management of Hemorrhoidal Disease: An Historical Overview

Hemorrhoidal disease (HD) is the symptomatic enlargement and/or distal displacement of the normal hemorrhoidal cushions and is one of the most frequent diseases in colorectal surgery. Several surgical or office-based therapies are currently available, with the aim of being a more tailored approach. This article aimed to elucidate the historical evolution of surgical therapy for HD from ancient times, highlighting the crucial steps, controversies, and pioneers in the field. In contrast with the previous literature on the topic that is often updated to the 1990s, with the introduction of stapled hemorrhoidopexy and transanal hemorrhoidal dearterialization, this article describes all new surgical and office-based treatments introduced in the first 20 years of the 2000s

Robotic Abdominal Surgery and COVID-19: A Systematic Review of Published Literature and Peer-Reviewed Guidelines during the SARS-CoV-2 Pandemic

SARS-CoV-2; Abdominal surgery; Robotic surgerySARS-CoV-2; Cirugía abdominal; Cirugía robóticaSARS-CoV-2; Cirurgia abdominal; Cirurgia robòticaBackground: Significant concern emerged at the beginning of the SARS-CoV-2 pandemic regarding the safety and practicality of robotic-assisted surgery (RAS). We aimed to review reported surgical practice and peer-reviewed published review recommendations and guidelines relating to RAS during the pandemic. Methods: A systematic review was performed in keeping with PRISMA guidelines. This study was registered on Open Science Framework. Databases were searched using the following search terms: ‘robotic surgery’, ‘robotics’, ‘COVID-19’, and ‘SARS-CoV-2’. Firstly, articles describing any outcome from or reference to robotic surgery during the COVID-19/SARS-CoV-2 pandemic were considered for inclusion. Guidelines or review articles that outlined recommendations were included if published in a peer-reviewed journal and incorporating direct reference to RAS practice during the pandemic. The ROBINS-I (Risk of Bias in Non-Randomised Studies of Intervention) tool was used to assess the quality of surgical practice articles and guidelines and recommendation publications were assessed using the AGREE-II reporting tool. Publication trends, median time from submission to acceptance were reported along with clinical outcomes and practice recommendations. Results: Twenty-nine articles were included: 15 reporting RAS practice and 14 comprising peer-reviewed guidelines or review recommendations related to RAS during the pandemic, with multiple specialities (i.e., urology, colorectal, digestive surgery, and general minimally invasive surgery) covered. Included articles were published April 2020—December 2021, and the median interval from first submission to acceptance was 92 days. All surgical practice studies scored ‘low’ or ‘moderate’ risk of bias on the ROBINS-I assessment. All guidelines and recommendations scored ‘moderately well’ on the AGREE-II assessment; however, all underperformed in the domain of public and patient involvement. Overall, there were no increases in perioperative complication rates or mortalities in patients who underwent RAS compared to that expected in non-COVID practice. RAS was deemed safe, with recommendations for mitigation of risk of viral transmission. Conclusions: Continuation of RAS was feasible and safe during the SARS-CoV-2 pandemic where resources permitted. Post-pandemic reflections upon published robotic data and publication patterns allows us to better prepare for future events and to enhance urgent guideline design processes

Bruno da Longobucco (da Longoburgo): The first academic surgeon in the Middle Ages

Bruno da Longobucco; Surgeon; Middle AgesBruno da Longobucco; Cirurgià; Edat MitjanaBruno da Longobucco; Cirujano; Edad MediaBruno da Longobucco (1200–1286 BC) was born at the turn of the 13th Century in Longobucco (Calabria, Italy), at that time named Longoburgo. He was the first academic surgeon of the Middle Ages, a period when surgery was disregarded by mainstream physicians and was the practice of barbers, charlatans and phlebotomists. After training at the medical school of Salerno and the University of Boulogne, he was one of the founders of the University of Padua and became the first Professor of Surgery. His books Chirurgia Magna and Chirurgia Parva, were ones of the most disseminated surgical texts of the Middle Ages and it is argued helped surgery regain its reputation. Despite his importance to late medieval period, he has been essentially overlooked in the records of the history of surgery. Currently, there are no articles in English about his life indexed on PubMed, Scopus or Embase. One solitary article on Bruno's life and influence was published in 1960s in a small journal in Italian, but this is no longer active and there is no electronic means to access the original article. The aim of this article is to provide education and rediscovery of the impact of this critical figure, his works and his historic role to the development and renaissance of surgery for contemporary surgeons.The authors thank the municipality of town of Longobucco (Comune di Longobucco), Italy, for the financial support to cover the publication fees of this article

Bruno da Longobucco (da Longoburgo): The first academic surgeon in the Middle Ages

Bruno da Longobucco (1200–1286 BC) was born at the turn of the 13th Century in Longobucco (Calabria, Italy), at that time named Longoburgo. He was the first academic surgeon of the Middle Ages, a period when surgery was disregarded by mainstream physicians and was the practice of barbers, charlatans and phlebotomists. After training at the medical school of Salerno and the University of Boulogne, he was one of the founders of the University of Padua and became the first Professor of Surgery. His books Chirurgia Magna and Chirurgia Parva, were ones of the most disseminated surgical texts of the Middle Ages and it is argued helped surgery regain its reputation. Despite his importance to late medieval period, he has been essentially overlooked in the records of the history of surgery. Currently, there are no articles in English about his life indexed on PubMed, Scopus or Embase. One solitary article on Bruno's life and influence was published in 1960s in a small journal in Italian, but this is no longer active and there is no electronic means to access the original article. The aim of this article is to provide education and rediscovery of the impact of this critical figure, his works and his historic role to the development and renaissance of surgery for contemporary surgeons

An international survey exploring the management of pilonidal disease

AIM: Pilonidal disease (PD) is a common debilitating condition frequently seen in surgical practice. Several available treatments carry different benefit/risk balances. The aim of this study was to snapshot the current management of PD across European countries.METHOD: Members affiliated to the European Society of Coloproctology were invited to join the survey. An invitation was extended to others via social media. The predictive power of respondents' and hospitals' demographics on the change of therapeutic approach was explored.RESULTS: Respondents (n = 452) were mostly men (77%), aged 26-60 years, practising in both academic and public hospitals and with fair distribution between colorectal (51%) and general (48%) surgeons. A total of 331 (73%) respondents recommended surgery at first presentation of the disease. Up to 80% of them recommended antibiotic therapy and 95% did not use any classification of PD. A primary closure technique was the preferred procedure (29%), followed by open technique (22%), flap creation (7%), sinusectomy (7%) and marsupialization (7%). Approximately 27% of subjects would choose the same surgical technique even after a failure. Almost half (46%) perform surgery as office based. A conservative approach was negatively associated with acutely presenting PD (p &lt; 0.001). Respondents who were not considering tailored surgery based on patient presentation tended to change their approach in the case of a failed procedure.CONCLUSION: With the caveat of a heterogeneous number of respondents across countries, the results of our snapshot survey may inform the development of future guidelines.</p