Optimal Time-Consistent Investment and Premium Control Strategies for Insurers with Constraint under the Heston Model

In this work, we study the optimal investment and premium control problem with the short-selling constraint under the mean-variance criterion. The claim process is assumed to follow the non-homogeneous compound Poisson process. The insurer invests the surplus in one risk-free asset and one risky asset described by the Heston model. Under these, we consider an optimization objective that maximizes the return (the expectation of terminal wealth) and minimizes the risk (the variance of terminal wealth). By constructing the extended Hamilton–Jacobi–Bellman (HJB) system with the dynamic programming method, the time-consistent strategies and the corresponding value function are obtained. Furthermore, we provide numerical examples to illustrate the effects of the model parameters on the optimal policies.

Tocilizumab: The Key to Stop Coronavirus Disease 2019 (COVID-19)-Induced Cytokine Release Syndrome (CRS)?

The COVID-19 disease is an unprecedented international public health emergency and considerably impacts the global economy and health service system. While awaiting the development of an effective vaccine, searching for the therapy for severe or critical COVID-19 patients is essential for reducing the mortality and alleviating the tension of the health service system. Cytokine release syndrome (CRS) induced by elevated interleukin-6 was recognized to underscore the pathology of severe COVID-19 patients. Inhibiting CRS by agents suppressing IL-6 may relieve symptoms, shorten the hospital stay and reduce the need for oxygen therapy. Although evidence from randomized, double-blinded clinical trials is still lacking, the IL-6R inhibitor tocilizumab (TCZ) has shown some clinical benefits in the treatment of severe COVID-19 patients and have been included in clinical guidelines. In this review, we focused on the possible mechanisms of TCZ in the treatment of CRS and highlighted some significant considerations in the use of TCZ to treat COVID-19 patients.

SARS-CoV-2 suppresses mRNA expression of selenoproteins associated with ferroptosis, endoplasmic reticulum stress and DNA synthesis.

Higher selenium status has been shown to improve the clinical outcome of infections caused by a range of evolutionally diverse viruses, including SARS-CoV-2. However, the impact of SARS-CoV-2 on host-cell selenoproteins remains elusive. The present study investigated the influence of SARS-CoV-2 on expression of selenoprotein mRNAs in Vero cells. SARS-CoV-2 triggered an inflammatory response as evidenced by increased IL-6 expression. Of the 25 selenoproteins, SARS-CoV-2 significantly suppressed mRNA expression of ferroptosis-associated GPX4, DNA synthesis-related TXNRD3 and endoplasmic reticulum-resident SELENOF, SELENOK, SELENOM and SELENOS. Computational analysis has predicted an antisense interaction between SARS-CoV-2 and TXNRD3 mRNA, which is translated with high efficiency in the lung. Here, we confirmed the predicted SARS-CoV-2/TXNRD3 antisense interaction in vitro using DNA oligonucleotides, providing a plausible mechanism for the observed mRNA knockdown. Inhibition of TXNRD decreases DNA synthesis which is thereby likely to increase the ribonucleotide pool for RNA synthesis and, accordingly, RNA virus production. The present findings provide evidence for a direct inhibitory effect of SARS-CoV-2 replication on the expression of a specific set of selenoprotein mRNAs, which merits further investigation in the light of established evidence for correlations between dietary selenium status and the outcome of SARS-CoV-2 infection.

The Centrality of Obesity in the Course of Severe COVID-19.

The ongoing coronavirus disease 2019 (COVID-19) pandemic caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become a global public health challenge. Most patients do not experience severe complications, but approximately 25% of patients progress to acute respiratory distress syndrome (ARDS), and the mortality rate is approximately 5-7%. Clinical findings have determined several risk factors for severe complications and mortality in COVID-19 patients, such as advanced age, smoking, obesity, and chronic diseases. Obesity is a common and serious health problem worldwide that initiates a cascade of disorders, including hypertension, cardiovascular disease (CVD), diabetes mellitus, and chronic kidney disease (CKD). The presence of these disorders is linked to a more severe course of COVID-19. Given the "epidemic" of obesity worldwide and the importance of obesity in the progression of COVID-19, we investigated the mechanisms through which obesity increases the susceptibility to and severity of COVID-19 to support the selection of more appropriate therapies for individuals with obesity.