Hyaline fibromatosis syndrome (juvenile hyaline fibromatosis): whole-body MR findings in two siblings with different subcutaneous nodules distribution

Abstract: Hyaline fibromatosis syndrome (juvenile hyaline fibromatosis) is a rare, progressive, autosomal recessive disorder whose main hallmark is the deposition of amorphous hyaline material in soft tissues, with an evolutionary course and health impairment. It may present involvement of subcutaneous or periskeletal soft tissue, or may develop as a visceral infiltration entity with poor prognosis. Very few radiological data about this inherited condition have been reported, due to the extreme rarity of disease. We herein present a case of two siblings, affected by different severity of the disease, with different clinical features. They were examined by whole-body MR (WBMR) in order to assess different lesions localization, to rule out any visceral involvement and any other associated anomalies and to define patients\ue2\u80\u99 management

Copulae and correlation products

This thesis studies copula applications to correlation products. There are six self-contained but related projects in this research, with the following objectives: 1) to review reduced-form approaches to model the default process of a single-name obligor and their extension to model the joint distribution of defaults in a portfolio of obligors; 2) to set up the CDO market; 3) to introduce copulae and to provide a justification of copulae as modelling tools; 4) to provide with our view regarding the most suitable copula when modelling complex correlation products; 5) to prepare a time-inhomogeneous intensity model for valuing cash-flow CDOs, which explicitly incorporates the credit rating of the firms in the collateral portfolio as the indicator of the likelihood of default; 6) to prepare a pricing model for CDOs of EDSs. We found strong evidence that the Clayton copula is a suitable tool when modelling correlation products with Li’s Survival model. The Clayton copula had some important consequences: we noticed a redistribution of losses from the Junior note to the Mezzanine and Senior notes; in addition, it picked up some extra risk in the Senior note, and finally, when compared with the Normal copula, it overestimated the fair compensation of the Senior and the Mezzanine notes and underestimated the fair compensation of the Junior note. We also found the Clayton copula was very adaptable into the dynamic copula framework of Schonbucher and Schubert. Modelling the notes of cash-flow CDOs with copulae and time-inhomogeneous transition matrices has not been an easy task. This is because the computation of the transition matrices for arbitrary periods of time was based on an annual transition matrix. In addition, this matrix, as most of the empirical annual transition matrices, was not compatible with a continuous Markov process since it did not admit a valid generator. Therefore, we computed a modified version of a true generator. Following this, we successfully applied one method, originally advanced by JLT (1997), to calibrate the adjusted matrix to the S&P’s probabilities of default. Finally, we described how to simulate the credit rating migration of one single credit, and how to join n -credit rating migrations via the Normal copula. Modelling the collateral credit risk in this way is very powerful, since it allowed us to take into account quality trigger linked to the rating-performance of the collateral and to keep the model of the joint credit rating migrations, totally separate with copulae. For example, when there are performance triggers linked to the collateral average rating, our Rating Transition Copula model perfectly captures the diversion of cash from the interest waterfall to the principal waterfall for the benefit of the Senior and Mezzanine notes. To price single-name Equity Default Swaps and CDOs of Equity Default Swaps, we extended the GARCH option framework of Duan (1995). Volatility of the underlying equity price is the critical factor affecting option prices, and in our EDS model, the variance of the equity return followed a nonlinear GARCH in mean. When pricing single-name EDS, we proposed two nonlinear GARCH in mean (NGARCH-M): normal and /-Student NGARCH-M model. As a benchmark, we assumed that the equity returns moved accordingly to the standard homoskedastic lognormal process of Black & Scholes and priced the single-name EDS with the Rubinstein and Reiner model for binary barrier options. The problem we found with this approach was that the implied volatilities for very deep out-of-the-money put options were not available. When the volatility was modelled as a GARCH process, it was not possible to derive the future distribution of the underlying equity. Therefore, our model relied on Monte Carlo simulations. To ensure that the simulated option price did not violate rational option pricing bounds, we used the empirical martingale simulation originally advanced by Duan and Simonato, coupled with the standard variance reduction technique. To address the issue of how to price a basket of EDSs, we resorted to the concept of copula. With copulae, we were able to decouple the pricing problem: keeping the aspect of modelling the marginal distribution of the equity returns via NGARCH-M, totally separate from addressing the dependence problem

Detection of liver metastases in cancer patients with geographic fatty infiltration of the liver: the added value of contrast-enhanced sonography

The aim of this study is to assess the role of contrast-enhanced ultrasonography (CEUS) in the detection of liver metastases in cancer patients with geographic liver fatty deposition on greyscale ultrasonography (US)

MR Imaging of Perianal Crohn Disease: The Role of Contrast-enhanced Sequences

The MR imaging protocol described by the authors includes contrast-enhanced T1-weighted imaging with fat saturation in all patients except those with poor renal function. Horsthuis et al demonstrated in 2009 the usefulness of contrast-enhanced MR imaging for determining disease activity. Contrast agent administration is also required in case of suspicion of neoplastic tissue complicating fistulas. The joint European Crohn\u2019s and Colitis Organisation\u2013European Society of Gastointestinal and Abdominal Radiology guidelines report that T2-weighted images and contrast-enhanced T1-weighted images are included in the MR imaging protocol for the evaluation of perianal CD. However, as we have demonstrated, an axial T2-weighted fast spinecho sequence with fat saturation, in particular the short inversion time inversion-recovery (STIR) sequence, is a valid alternative to postcontrast T1- weighted fat-saturated imaging, allowing the identification of the primary fistula and any secondary ramification

Post-acute COVID-19 neurological syndrome: A new medical challenge

In December 2019, in Wuhan (China), a highly pathogenic coronavirus, named SARS-CoV-2, dramatically emerged. This new virus, which causes severe pneumonia, is rapidly spreading around the world, hence it provoked the COVID-19 pandemic. This emergency launched by SARS-CoV-2 also had, and still has, devastating socio-economic aspects. Assessing the impact of COVID-19 on vulnerable groups of people is crucial for the adaptation of governments’ responses. Growing scientific evidence suggests that it is essential to keep the attention on people after acute SARS-CoV-2 infection; indeed, some clinical manifestations are frequently present even after recovery. There is consensus on the need to define which symptoms persist after the infection and which disabilities may arise after COVID-19. Recent reviews, case reports, and original contributions suggest that various organs may be affected, and neurological symptoms are present in about one third of patients with COVID-19. Neurological complications after severe COVID-19 infection might include delirium, brain inflammation, stroke, and nerve damage. In the recent pandemic, neurologists and neurobiologists have a chance to study key features of infection neurology. Furthermore, the psychological impact of the pandemic should not be underestimated, although there is currently no definition for this condition

Small Bowel Perforations: What the Radiologist Needs to Know

The incidence of small bowel perforation is low but can develop from a variety of causes including Crohn disease, ischemic or bacterial enteritis, diverticulitis, bowel obstruction, volvulus, intussusception, trauma, and ingested foreign bodies. In contrast to gastroduodenal perforation, the amount of extraluminal air in small bowel perforation is small or absent in most cases. This article will illustrate the main aspects of small bowel perforation, focusing on anatomical reasons of radiological findings and in the evaluation of the site of perforation using plain film, ultrasound, and multidetector computed tomography equipments. In particular, the authors highlight the anatomic key notes and the different direct and indirect imaging signs of small bowel perforation

Insulin Promotes Survival of Amyloid-Beta Oligomers Neuroblastoma Damaged Cells via Caspase 9 Inhibition and Hsp70 Upregulation

Alzheimer's disease (AD) and type 2 diabetes are connected in a way that is still not completely understood, but insulin resistance has been implicated as a risk factor for developing AD. Here we show an evidence that insulin is capable of reducing cytotoxicity induced by Amyloid-beta peptides (A-beta) in its oligomeric form in a dose-dependent manner. By TUNEL and biochemical assays we demonstrate that the recovery of the cell viability is obtained by inhibition of intrinsic apoptotic program, triggered by A-beta and involving caspase 9 and 3 activation. A protective role of insulin on mitochondrial damage is also shown by using Mito-red vital dye. Furthermore, A-beta activates the stress inducible Hsp70 protein in LAN5 cells and an overexpression is detectable after the addition of insulin, suggesting that this major induction is the necessary condition to activate a cell survival program. Together, these results may provide opportunities for the design of preventive and therapeutic strategies against AD