Search

Caused by four serotypes, dengue fever is a major public health concern worldwide. Current modeling efforts have mostly focused on primary and heterologous secondary infections, assuming that lifelong immunity prevents reinfections by the same serotype. However, recent findings challenge this assumption, prompting a reevaluation of dengue immunity dynamics.In this study, we develop a within-host modeling framework to explore different scenarios of dengue infections. Unlike previous studies, we go beyond a deterministic framework, considering individual immunological variability. Both deterministic and stochastic models are calibrated using empirical data on viral load and antibody (IgM and IgG) concentrations for all dengue serotypes, incorporating confidence intervals derived from stochastic realizations.With good agreement between the mean of the stochastic realizations and the mean field solution for each model, our approach not only successfully captures primary and heterologous secondary infection dynamics facilitated by antibody-dependent enhancement (ADE) but also provides, for the first time, insights into homotypic reinfection dynamics. Our study discusses the relevance of homotypic reinfections in dengue transmission at the population level, highlighting potential implications for disease prevention and control strategies.

Background/Objective: Paragangliomas are rare neuroendocrine tumors that primarily arise in the adrenal gland. Head and neck paragangliomas comprise approximately 3% of all extra-adrenal paragangliomas, with a majority of those being found in the carotid body. Recurrent laryngeal nerve paragangliomas are exceedingly rare, with only 2 reported cases found in literature review. Here, we will present the third. Case Report: The patient is a 46-year-old woman with a history of a right thyroid nodule that had been previously biopsied benign with “paucity of diagnostic material.” Neck ultrasonography revealed a 7.4 cm nodule that demonstrated interval growth over a 2-year period, so it was recommended to proceed with right thyroid lobectomy and isthmusectomy. During resection, the recurrent laryngeal nerve appeared to “disappear” into the nodule, and it was resected along with the nodule to ensure proper margins. The nerve was reconstructed with an ansa cervicalis interposition graft, and the nodule was sent to pathology. Pathology revealed that the nodule was a 4.8 cm paraganglioma of the recurrent laryngeal nerve. Discussion: Paragangliomas of the head and neck are exceedingly rare. In patients who present with symptoms of dysphagia or dysphonia, further workup, including laryngoscopy and magnetic resonance imaging, could potentially identify and allow for appropriate planning for surgical resection. Conclusion: In rare cases, consideration of paraganglioma as part of the differential for thyroid nodules may assist with planning of surgery but will unlikely alter treatment.

This paper presents a mathematical model of the cardiovascular system (CVS) designed to simulate both normal and pathological conditions within the systemic circulation. The model introduces a novel representation of the CVS through a change of coordinates, transforming it into the “quadratic normal form”. This model facilitates the implementation of a sliding mode observer (SMO), allowing for the estimation of system states and the detection of anomalies, even though the system is linearly unobservable. The primary focus is on identifying valvular heart diseases, which are significant risk factors for cardiovascular diseases. The model’s validity is confirmed through simulations that replicate hemodynamic parameters, aligning with existing literature and experimental data.