In Silico Shear and Intramural Stresses are Linked to Aortic Valve Morphology in Dilated Ascending Aorta.

OBJECTIVE/BACKGROUND: The development of ascending aortic dilatation in patients with bicuspid aortic valve (BAV) is highly variable, and this makes surgical decision strategies particularly challenging. The purpose of this study was to identify new predictors, other than the well established aortic size, that may help to stratify the risk of aortic dilatation in BAV patients. METHODS: Using fluid-structure interaction analysis, both haemodynamic and structural parameters exerted on the ascending aortic wall of patients with either BAV (n = 21) or tricuspid aortic valve (TAV; n = 13) with comparable age and aortic diameter (42.7 ± 5.3 mm for BAV and 45.4 ± 10.0 mm for TAV) were compared. BAV phenotypes were stratified according to the leaflet fusion pattern and aortic shape. RESULTS: Systolic wall shear stress (WSS) of BAV patients was higher than TAV patients at the sinotubular junction (6.8 ± 3.3 N/m2 for BAV and 3.9 ± 1.3 N/m2 for TAV; p = .006) and mid-ascending aorta (9.8 ± 3.3 N/m2 for BAV and 7.1 ± 2.3 N/m2 for TAV; p = .040). A statistically significant difference in BAV versus TAV was also observed for the intramural stress along the ascending aorta (e.g., 2.54 × 105 ± 0.32 × 105 N/m2 for BAV and 2.04 × 105 ± 0.34 × 105 N/m2 for TAV; p < .001) and pressure index (0.329 ± 0.107 for BAV and 0.223 ± 0.139 for TAV; p = .030). Differences in the BAV phenotypes (i.e., BAV type 1 vs. BAV type 2) and aortopathy (i.e., isolated tubular vs. aortic root dilatations) were associated with asymmetric WSS distributions in the right anterior aortic wall and right posterior aortic wall, respectively. CONCLUSION: These findings suggest that valve mediated haemodynamic and structural parameters may be used to identify which regions of aortic wall are at greater stress and enable the development of a personalised approach for the diagnosis and management of aortic dilatation beyond traditional guidelines.

Organization and maintenance of Drosophila telomeres: the roles of terminin and non-terminin proteins.

Drosophila telomeres are elongated by occasional transposition of specialized retroelements rather than telomerase activity, and are assembled independently of the sequence of the DNA termini. Drosophila telomeres are capped by terminin, a complex formed by the HOAP, Moi, Ver and HipHop proteins that localize exclusively at telomeres and protect them from fusion events. Other proteins required to prevent end-to-end fusion include HP 1 Eff/UbcD 1, ATM, the components of the Mrel 1-Rad50-Nbs (MRN) complex, and the Woc transcription factor. The terminin proteins are encoded by fast-evolving genes and are not evolutionarily conserved outside the Drosophila species. In contrast, the non-terminin telomere capping proteins are not fast-evolving, do not localize only at telomeres and are conserved from yeasts to mammals. We propose that following telomerase loss, Drosophila rapidly evolved terminin to bind chromosome ends in a sequence-independent manner, and that non-terminin proteins did not evolve as rapidly as terminin because of the functional constraints imposed by their involvement in diverse cellular processes. This hypothesis suggests that the Drosophila non-terminin proteins might correspond to ancestral telomere-associated proteins with homologues in other organisms including humans.

David operation: single center 10-year experience.

AIM: Aortic valve-sparing operation has been progressively widely performed for the treatment of aortic root aneurysm. Nowadays, this procedure has been proposed even in presence of a bicuspid aortic valve, severe aortic regurgitation or in primary aortic dissection repair. We present our ten-year experience focusing on mid-term echocardiographic follow-up. METHODS: Between June 2002 and February 2012, 139 patients (mean age of 61±12 years) underwent aortic valve-sparing operation with valve reimplantation. Twenty-seven patients (19%) had bicuspid aortic valve; in eighteen cases (13%) cusp motion or anatomical abnormalities concurred in determining aortic regurgitation and needed an adjunct cusp repair. A Gelweave Valsalva™ graft was implanted in all the patients. RESULTS: The mortality pre-discharge was 0.7% (1 patient). The cumulative 1-year, 5-years and 8-years survival rates were 99%, 93% and 87% respectively. Postoperative aortic regurgitation more than mild degree (>2+/4+) was the only significant risk factors for redo aortic valve surgery Freedom from reoperation due to aortic valve regurgitation was 96% at 1 year, 90% at 5 years and 86% at 8 years. When comparing freedom from reoperation in patients with bicuspid vs tricuspid aortic valve, no differences were found (P=0.31) and the rate of aortic valve reoperation was significantly higher (P<0.001) in patients who received leaflet's repair. CONCLUSION: The durability of valve reimplantation was found to be excellent in patients with tricuspid aortic valve and normal or nearly normal cusps. Cusp prolapse and complication after cusp repair turned out to be the main causes for early failure.

Novel achromatic single reflection quarter-wave retarder: design and measurement.

In this work, we present an achromatic quarter-wave retarder whose design is based upon the reflection properties of an isotropic-anisotropic interface. In theory, it is possible to obtain a π/2 phase shift by means of a total internal reflection at an isotropic-isotropic interface. However, in order to achieve such a phase shift, it is necessary to use a medium with a particularly high refractive index. We have previously shown that these phase shifts can be achieved by means of a total internal reflection in an isotropic-uniaxial interface, which allows the use of smaller refractive index media. By means of this property, we designed, built, and characterized a novel quarter-wave retarder that makes it possible to obtain circularly polarized light from a linear polarization state. We developed some guidelines that allowed us to obtain a device of competitive performance, low cost, and manageable manufacture.

Potential clinical role of telomere length in human glioblastoma.

Glioblastoma Multiforme (GBM) is the most common and lethal of human primary central nervous system (CNS) tumors. Due to the tumour's intrinsic clinical and molecular heterogeneity, choice of initial treatment, prediction of survival, stratification of patients, prediction and monitoring of response to therapy, represent some of the greatest challenges in the management of GBM patients. Patients, despite optimal surgery, radiation and chemotherapy, still have a median survival of 14-16 months. A reason for this dismal prognosis is because of the relative inaccuracy of current prognostic markers, so far based on clinical or pathological variables. Molecular markers that effectively predict response to therapy and survival outcomes are limited. Consequently, there is a strong need to develop novel and independent markers of prognosis. Ideal biomarkers for solid tumors would serve one or more important functions. Telomeres, guanine-rich tandem DNA repeats of the chromosomal end, provide chromosomal stability, regulates important cellular processes, and seem to be implicated in human carcinogenesis. Recently, telomeres have been shown either to be associated with clinical markers of disease progression or to be independent markers of cancer prognosis in solid tumours, including GBM. Nevertheless, a corresponding comprehensive discussion of these promising developments in brain tumours has not yet been available in the literature. Therefore, here we reviewed studies focused on the assessment of telomeric length in brain tumours with the aim to emphasized those findings indicating a potential clinical role of telomeres in GBM. With the aim to enhance the awareness of the potential clinical role of telomeres' length information in GBM, using a southern blot analysis, telomeric length in excised tumour samples was analyzed. Moreover, an attempt to correlated telomere length with patients' overall survival, was also performed. The findings here reviewed shows some contradictory results, due to different tissues used as controls, but mainly to cellular and molecular heterogeneity in GBMs that drive molecular mechanisms controlling telomere length, included telomerase and Alternative Lengthening of Telomeres (ALT), through multiple mechanisms. However, overall these studies, including our own, are consistent with the hypothesis that GBMs' telomeres were always shorter when compared with Normal Brain Tissue (NBT), and together with higher telomerase activity seem to be associated with malignancy and poor outcome; while tumours with ALT phenotype have longer telomeres, "less malignant" behaviour and better prognosis. We conclude that, although not entirely consistent in the type of telomere alteration, i.e., attrition vs. elongation, and unclear on the underlying mechanisms, multiple studies in brain tumours have shown that telomere dysfunctions are associated with parameters of clinical outcome in patients with GBMs and therefore will be part of novel risk assessment and prognostic modalities for patients with these still dismal disease.

Incidence of neoplastic disease following lung transplantation: a 17-year single-center experience.

OBJECTIVE: Chronic immunosuppressive therapy following solid organ transplantation has been correlated with an increased risk of posttransplantation neoplastic disease (PTND). In this study we evaluated PTND incidence and outcome at our institution over a 17-year period among patients receiving lung transplantation. MATERIALS AND METHODS: Between February 1992 and December 2008, we performed 290 lung transplantations in 280 patients, including 139 single (48% with 5 retransplantations), and 151 double lung transplantations (52% with 5 retransplantations). Among the 280 patients, 2 had undergone previous double lung transplantation in other hospitals. Follow-up of transplant recipients was performed up to December 2009. RESULTS: Forty-two patients died in the hospital, producing a cumulative early (30-day) mortality rate of 15%. Among the 238 patients discharged from the hospital who entered our follow-up program, 36 (15%) experienced PTND. The mean time between transplantation and diagnosis was 47 ± 42 months, and patients' mean age at time of diagnosis was 55 ± 14 years. Overall freedom from PTND was 97%, 84%, and 73% at 1, 5, and 10 years, respectively. PTND was considered to be the direct cause of death in 11 patients (30%). Overall survival of patients with PTND at five years (45%) did not differ from the remainder of the transplanted population (46%). However, PTND became a relevant cause of death in the long-term (>5 years) follow-up. CONCLUSION: Our experience confirms that PTND was frequently diagnosed following lung transplantation. Even if PTND did not seem to significantly affect the survival of patients undergoing lung transplantation, it may become a significant cause of death among those surviving beyond 5 years.

Domino heart transplantation: long-term outcome of recipients and their living donors: single center experience.

BACKGROUND: "Domino" cardiac procedure is an effective option to increase the donor pool when heart-lung transplantation (HLT) is the only treatment for patients with terminal cardiopneumopathy. We reviewed the long-term outcomes of domino cardiac donors and recipients at our institution. METHODS: Ten of 35 patients who underwent HLT from 1991 onward served as domino cardiac donors. They included eight female and two male subjects of overall mean age of 33 years and mean weight of 55 kg. Their diagnoses were primary pulmonary hypertension (n = 6) as well as cystic fibrosis, bronchiectasis, Eisenmenger's syndrome, and bronchiolitis obliterans (n = 1 each). The domino cardiac recipients included six males and four females of overall mean age of 47 years and mean weight of 61 kg. They were affected by ischemic heart disease (n = 5), cardiomyopathy (n = 4), and valvular heart disease (n = 1). Mean pulmonary vascular resistance was 3 Wood units. The heart was used either in the orthotopic (n = 8) or in the heterotopic position (n = 2). RESULTS: The 1-, 5-, and 10-year survivals for the domino cardiac donors versus their recipients were 60%, 40%, 30% versus 90%, 70%, 60%, respectively. Five domino donors developed bronchiolitis obliterans syndrome. Among the domino recipients group, cardiac allograft vasculopathy was rare (n = 1). Common causes of late death were in the domino recipients infections in the domino donors (n = 2) and malignancies. CONCLUSIONS: Our experience suggested good long-term results of the domino procedure.

Is investigation of hepatitis C virus NS5A gene heterogeneity a tool for predicting long-lasting response to interferon therapy in patients with HCV-1b chronic hepatitis?

Nonstructural protein 5A (NS5A) of the hepatitis C virus (HCV) may repress the interferon (IFN)-induced protein kinase R (PKR). High variability of different regions in the carboxy-terminal half of NS5A implicated in the interaction with PKR (particularly the interferon sensitivity determining region (ISDR)) may be a predictor of response to IFN in patients infected with genotype 1b of HCV. We examined pretreatment serum samples from 17 HCV-1b infected patients included in the same schedule of IFN therapy. Seven patients were a rare series of sustained responders (SR) with a post-treatment follow-up of 5-7 years, while ten were nonresponders (NR). The carboxy-terminal half of the NS5A gene was amplified and directly sequenced in all 17 cases. In addition, the entire NS5A gene and the part of the HCV E2 gene coding for the hypervariable region 1 (HVR1) were amplified, cloned and sequenced in six cases (three NR and three SR). No difference in number and distribution of amino acid mutations was observed between isolates from SR and NR in any portion of the protein, including the ISDR region. Analysis of full length NS5A confirmed no difference between the two groups. The NS5A gene sequence was different among the six cases cloned although it appeared to be conserved in each individual patient independently of the quasispecies complexity evaluated through HVR1 examination. These data indicate that pretreatment analysis of theNS5A genomic variability has no value in predicting long-lasting response to IFN therapy in HCV-1b-infected patients, and that the HCV NS5A gene has high quasispecies homology.

Analysis of haemochromatosis gene mutations in a population from the Mediterranean Basin.

BACKGROUND/AIMS: The C282Y mutation in the haemochromatosis gene (HFE) located on chromosome 6 has been identified as the main genetic basis of hereditary haemochromatosis (HH). Two more mutations of that gene, H63D and S65C, appear to be associated with milder forms of HH. A high allele frequency for C282Y and H63D mutations was reported in populations from North Europe, while incomplete information is available for individuals from the Mediterranean Basin where C282Y homozygotes comprise a smaller percentage of HH cases. In this study we investigated the allele frequency of HFE mutations and the association between HFE mutations and cases of HH in a population from the South of Italy (Sicily and Calabria). In addition, we evaluated a possible association between HFE mutations and either chronic liver disease or type II diabetes. PATIENTS AND METHODS: Three hundred and twenty-seven individuals (654 chromosomes) were tested for C282Y, H63D and S65C mutations of the HFE gene by restriction fragment length polymorphism. Four had HH, 23 had hepatocellular carcinoma, 100 had chronic liver disease, 100 had type II diabetes, and 100 were healthy controls. RESULTS: Both C282Y and S65C mutations were each detected in one of the 654 chromosomes analysed (allele frequency=0.15%), while H63D change was found in 122 chromosomes (allele frequency=18.6%) and was equally distributed in all the categories examined. One healthy individual had compound heterozygosity for C282Y and H63D mutations. The frequency of C282Y in this Southern Italian sample was the lowest yet reported for a population of European origin. None of the four HH patients was either homozygous or heterozygous for C282Y. CONCLUSIONS: In Mediterranean populations from Southern Italy the C282Y mutation occurs sporadically and HFE polymorphisms seem to have little diagnostic relevance.

TT virus has a ubiquitous diffusion in human body tissues: analyses of paired serum and tissue samples.

The tissue tropism and possible correlation with liver disease of the TT virus (TTV) as well as its prevalence and genotype distribution remain undefined. TTV-DNA was investigated in paired sera and tissue samples from 144 patients, and sera and cerebrospinal fluids (CSF) from additional six subjects. Of the 144 tissue samples, 128 were liver biopsy specimens from subjects with hepatic disease while 16 were surgically obtained nonliver specimens from patients with extrahepatic disease. TTV cloning, sequencing and genotype analyses were performed on isolates from sera, tissue specimens and peripheral blood mononuclear cells of two patients with hepatic and four patients with extrahepatic pathologies, as well as from sera and CSFs of two subjects. TTV was found in 100% of the examined tissues and in 60.1 and 50% of sera from patients with hepatic and extrahepatic pathologies, respectively. Moreover, TTV was detected in four of the six CSFs analysed but only in two correspondent sera. Genotyping revealed the coexistence of multiple TTV genotypes and genetic variants in each infected individual, and the analysis of TTV mRNA showed the presence of transcripts in all the six different tissues studied. These results indicate that the entire adult population in our area is more likely infected by TTV, although several subjects are not viraemic and that TTV infects many different human tissues and is able to invade the central nervous system.