Sparse metapiles for shear wave attenuation in half-spaces

We show that shear waves traveling towards the surface of a half-space medium can be attenuated via buried one-dimensional arrays of resonators -- here called metapiles -- arranged according to sparse patterns around a site to be isolated. Our focus is on shear waves approaching the surface along a direction perpendicular to the surface itself. First, we illustrate the behavior of metapiles, both experimentally and numerically, using 3D printed resonators embedded in an acrylic plate. Then, via numerical simulations, we extend this idea to the case study of an idealized soil half-space, and elucidate the influence of various design parameters on wave attenuation. Results of this work demonstrate that significant wave attenuation can be achieved by installing sparse resonating piles around a selected site on the free surface of the medium, rather than placing resonators directly underneath that same site. This work might have implications in metamaterial-based wave attenuation applications across scales

Repeated TACE in HCC after Fontan surgery and situs viscerum inversus: A case report

We describe the case of a 32-year-old man who developed a liver neoplasm due to previous Fontan surgery (FS) for a single ventricle anomaly and situs viscerum inversus. He was admitted to our hospital for suspected hepatocellular carcinoma during an Ultrasound (US) follow up. Computed tomography (CT) showed features of chronic liver disease and 7 cm hepatic nodule with arterial enhancement. Laboratory analyses documented preserved liver function and increased levels of alpha-fetoprotein. Trans-arterial-chemoembolization (TACE) was performed obtaining complete necrosis at 4 weeks of follow up and significant reduction of alpha-fetoprotein. The patient is currently in follow-up, being evaluated for further treatments and/or combined liver-heart transplantation. TACE is a therapeutic option for the treatment of patients with unresectable hepatocellular carcinoma (HCC) and with severe heart disease, like those submitted to FS and with also other vascular abnormalities like those correlated to situs viscerum inversus

Massive hepatic angiomyolipoma in a young woman with tuberous sclerosis complex: Significant clinical improvement during tamoxifen treatment

Background/AimsIsolated liver angiomyolipomas (AMLs) occur in about 40% of TSC patients. Because of their slow growth, these tumors are often asymptomatic. Since AMLs express estrogen and progesteron receptors we suggest the possible benefits of tamoxifen for the treatment of liver AMLs.MethodsWe report the case of a 26-year-old female affected by tuberous sclerosis (TSC2) with cerebral, renal and hepatic involvement admitted to the Liver Unit for severe malnutrition, anorexia and abdominal pain. MRI showed a grossly enlarged liver, causing severe gastric compression. The liver was entirely filled with multiple nodular lesions of different sizes. Liver biopsy showed tumoral tissue with microscopic and ultrastructural features of angiomyolipoma. All liver function tests were repeatedly normal. Prior to considering the patient for partial hepatectomy, she was administered tamoxifen (20mg b.i.d).ResultsAfter 6 months of tamoxifen treatment a greatly improved quality of life and a significant weight gain were observed. After 12 months the clinical conditions further improved and the MRI showed a significant reduction of the largest lesion with a liquid central area and a diminished compression of the stomach.ConclusionsThis is to our knowledge the first report in which tamoxifen has been successfully used in a TSC patient with multiple liver angiomyolipomas

Hepatitis B virus recurrence after liver transplantation: An old tale or a clear and present danger?

Hepatitis B virus (HBV) recurrence after liver transplantation (LT) has been described more than 50 years ago. Similarly, to other clinical conditions, in which impairment of host immune defense favors viral replication, early reports described in details recurrence and reactivation of HBV in liver transplant recipients. The evidence of a possible, severe, clinical evolution of HBV reappearance in a significant percentage of these patients, allowed to consider, for some years, HBV positivity a contraindication for LT. Moving from the old to the new millennium this picture has changed dramatically. Several studies contributed to establish efficient prophylactic protocols for HBV recurrence and with the advent of more potent anti-viral drugs an increased control of infection was achieved in transplanted patients as well as in the general immune-competent HBV population. Success obtained in the last decade led some authors to the conclusion that HBV is now to consider just as a "mere nuisance". However, with regard to HBV and LT, outstanding issues are still on the table: (1) A standard HBV prophylaxis protocol after transplant has not yet been clearly defined; (2) The evidence of HBV resistant strains to the most potent antiviral agents is claiming for a new generation of drugs; and (3) The possibility of prophylaxis withdrawal in some patients has been demonstrated, but reliable methods for their selection are still lacking. The evolution of LT for HBV is examined in detail in this review together with the description of the strategies adopted to prevent HBV recurrence and their pros and cons

HDV can constrain HBV genetic evolution in hbsag: Implications for the identification of innovative pharmacological targets

Chronic HBV + HDV infection is associated with greater risk of liver fibrosis, earlier hepatic decompensation, and liver cirrhosis hepatocellular carcinoma compared to HBV mono-infection. However, to-date no direct anti-HDV drugs are available in clinical practice. Here, we identified conserved and variable regions in HBsAg and HDAg domains in HBV + HDV infection, a critical finding for the design of innovative therapeutic agents. The extent of amino-acid variability was measured by Shannon-Entropy (Sn) in HBsAg genotype-D sequences from 31 HBV + HDV infected and 62 HBV mono-infected patients (comparable for demographics and virological-parameters), and in 47 HDAg genotype-1 sequences. Positions with Sn = 0 were defined as conserved. The percentage of conserved HBsAg-positions was significantly higher in HBV + HDV infection than HBV mono-infection (p = 0.001). Results were confirmed after stratification for HBeAg-status and patients’ age. A Sn = 0 at specific positions in the C-terminus HBsAg were correlated with higher HDV-RNA, suggesting that conservation of these positions can preserve HDV-fitness. Conversely, HDAg was characterized by a lower percentage of conserved-residues than HBsAg (p < 0.001), indicating higher functional plasticity. Furthermore, specific HDAg-mutations were significantly correlated with higher HDV-RNA, suggesting a role in conferring HDV replicative-advantage. Among HDAg-domains, only the virus-assembly signal exhibited a high genetic conservation (75% of conserved-residues). In conclusion, HDV can constrain HBsAg genetic evolution to preserve its fitness. The identification of conserved regions in HDAg poses the basis for designing innovative targets against HDV-infection

Superiority of the new sex-adjusted models to remove the female disadvantage restoring equity in liver transplant allocation

Background and Aims: Model for End-stage Liver Disease (MELD) and MELDNa are used worldwide to guide graft allocation in liver transplantation (LT). Evidence exists that females are penalized in the present allocation systems. Recently, new sex-adjusted scores have been proposed with improved performance respect to MELD and MELDNa. GEMA-Na, MELD 3.0, and sex-adjusted MELDNa were developed to improve the 90-day dropout prediction from the list. The present study aimed at evaluating the accuracy and calibration of these scores in an Italian setting. Methods: The primary outcome of the present study was the dropout from the list up to 90 days because of death or clinical deterioration. We retrospectively analysed data from 855 adults enlisted for liver transplantation in the Lazio region (Italy) (2012–2018). Ninety-day prediction of GEMA-Na, MELD 3.0 and sex-adjusted MELDNa with respect to MELD and MELDNa was analysed. Brier score and Brier Skill score were used for accuracy, and the Greenwood-Nam- D'Agostino test was used to evaluate the calibration of the models. Results: GEMA-Na (concordance = .82, 95% CI = .75–. 89), MELD 3.0 (concordance = .81, 95% CI = .74–. 87) and sex-adjusted MELDNa (concordance = .81, 95% CI = .74–.88) showed the best 90-day dropout prediction. GEMA-Na showed a higher increase in accuracy with respect to MELD (p = .03). No superiority was shown with respect to MELDNa. All the tested scores showed a good calibration of the models. Using GEMA-Na instead of MELD would potentially save one in nine dropouts and could save one dropout per 285 patients listed

Improvement of ALT decay kinetics by all-oral HCV treatment: Role of NS5A inhibitors and differences with IFN-based regimens

Background: Intracellular HCV-RNA reduction is a proposed mechanism of action of direct-acting antivirals (DAAs), alternative to hepatocytes elimination by pegylated-interferon plus ribavirin (PR). We modeled ALT and HCV-RNA kinetics in cirrhotic patients treated with currently-used all-DAA combinations to evaluate their mode of action and cytotoxicity compared with telaprevir (TVR)+PR. Study design: Mathematical modeling of ALT and HCV-RNA kinetics was performed in 111 HCV-1 cirrhotic patients, 81 treated with all-DAA regimens and 30 with TVR+PR. Kinetic-models and Cox-analysis were used to assess determinants of ALT-decay and normalization. Results: HCV-RNA kinetics was biphasic, reflecting a mean effectiveness in blocking viral production &gt;99.8%. The first-phase of viral-decline was faster in patients receiving NS5A-inhibitors compared to TVR+PR or sofosbuvir+simeprevir (p&lt;0.001), reflecting higher efficacy in blocking assembly/secretion. The second-phase, noted \u3b4 and attributed to infected-cell loss, was faster in patients receiving TVR+PR or sofosbuvir+simeprevir compared to NS5A-inhibitors (0.27 vs 0.21 d-1, respectively, p = 0.0012). In contrast the rate of ALT-normalization, noted \u3bb, was slower in patients receiving TVR+PR or sofosbuvir+simeprevir compared to NS5A-inhibitors (0.17 vs 0.27 d-1, respectively, p&lt;0.001). There was no significant association between the second-phase of viral-decline and ALT normalization rate and, for a given level of viral reduction, ALT-normalization was more profound in patients receiving DAA, and NS5A in particular, than TVR+PR. Conclusions: Our data support a process of HCV-clearance by all-DAA regimens potentiated by NS5A-inhibitor, and less relying upon hepatocyte death than IFN-containing regimens. This may underline a process of "cell-cure" by DAAs, leading to a fast improvement of liver homeostasis

Direct-acting antivirals and hepatocellular carcinoma in chronic hepatitis C: A few lights and many shadows

With the introduction of direct-acting antiviral agents (DAA), the rate of sustained virological response (SVR) in the treatment of hepatitis C virus (HCV) has radically improved to over 95%. Robust scientific evidence supports a beneficial role of SVR after interferon therapy in the progression of cirrhosis, resulting in a decreased incidence of hepatocellular carcinoma (HCC). However, a debate on the impact of DAAs on the development of HCC is ongoing. This review aimed to analyse the scientific literature regarding the risk of HCC in terms of its recurrence and occurrence after the use of DAAs to eradicate HCV infection. Among 11 studies examining HCC occurrence, the de novo incidence rate ranged from 0 to 7.4% (maximum follow-up: 18 mo). Among 18 studies regarding HCC recurrence, the rate ranged from 0 to 54.4% (maximum "not well-defined" followup: 32 mo). This review highlights the major difficulties in interpreting data and reconciling the results of the included studies. These difficulties include heterogeneous cohorts, potential misclassifications of HCC prior to DAA therapy, the absence of an adequate control group, short follow-up times and different kinds of follow-up. Moreover, no clinical feature-based scoring system accounts for the molecular characteristics and pathobiology of the tumours. Nonetheless, this review does not suggest that there is a higher rate of de novo HCC occurrence or recurrence after DAA therapy in patients with previous HCV infection. \ua9 2018 The Author(s). Published by Baishideng Publishing Group Inc. All rights reserved

Functional Role of the Secretin/Secretin Receptor Signaling During Cholestatic Liver Injury

Liver diseases are a major health concern and affect a large proportion of people worldwide. There are over 100 types of liver disorders, including cirrhosis, cholangiocarcinoma (CCA), hepatocellular carcinoma, and hepatitis. Despite the relevant number of people who are affected by liver diseases, and the increased awareness with regard to these disorders, the number of deaths corresponding to liver injury is expected to increase in the foreseeable future. One of the possible reasons for this is that a complete comprehension of the mechanisms of hepatic damage involving specific liver anatomical districts is lacking, and, as a consequence, current treatments available are suboptimal. A major burden in the clinical setting are chronic cholestatic liver diseases (e.g., primary biliary cholangitis [PBC], primary sclerosing cholangitis [PSC], biliary atresia), which target the biliary epithelium and are characterized by cholestasis.(1, 2) Because the secretin (Sct)/secretin receptor (SR) axis (expressed only by cholangiocytes in the liver)(3, 4) is the major regulator of ductal bile secretion,(5, 6) it is intuitive that this axis plays a key role in the maintenance of biliary homeostasis during the progression of cholangiopathies. For instance, PBC is characterized by reduced bicarbonate secretion, a phenomenon possibly impeding the formation of an HCO3 canalicular film (“bicarbonate umbrella”) on bile ducts, which has protective properties against highly concentrated bile acids (BAs).(1, 7, 8) In this review, we examined the molecular mechanisms by which the Sct/SR axis regulates biliary function and the homeostasis of the biliary epithelium in normal and pathophysiological conditions

Dolichol: A Component of the Cellular Antioxidant Machinery

Dolichol, an end product of the mevalonate pathway, has been proposed a biomarker of aging, but its biological role, not to mention its catabolism, has not been fully understood. UV-B radiation was used to induce oxidative stress in isolated rat hepatocytes by the collagenase method. Effects on dolichol, phospholipids-bound polyunsaturated fatty acids (PL PUFA) and known lipid soluble antioxidants [coenzyme Q (CoQ) and α-tocopherol] were studied. The increase in oxidative stress was detected by a probe sensitive to reactive oxygen species (ROS). Peroxidation of lipids was assessed by measuring the release of thiobarbituric acid reactive substances (TBARS). Dolichol, CoQ and α-tocopherol were assessed by high-pressure liquid chromatography (HPLC), PL PUFA by gas-liquid chromatography (GC). UV-B radiation caused an immediate increase in ROS as well as lipid peroxidation and a simultaneous decrease in the levels of dolichol and lipid soluble antioxidants. Decrease in dolichol paralleled changes in CoQ levels and was smaller than that in α-tocopherol. The addition of mevinolin, a competitive inhibitor of the enzyme 3-hydroxy-3-methylglutaryl CoA reductase (HMG-CoAR), magnified the loss of dolichol and was associated with an increase in TBARS production. Changes in PL PUFA were minor. These findings highlight that oxidative stress has very early and similar effects on dolichol and lipid soluble antioxidants. Lower levels of dolichol are associated with enhanced peroxidation of lipids, which suggest that dolichol may have a protective role in the antioxidant machinery of cell membranes and perhaps be a key to understanding some adverse effects of statin therapy