ABSTRACT
Coronavirus disease 2019 (COVID-19) is an infectious viral disease, manifesting primarily as a lung infection with fever and respiratory symptoms. However, it also has a wide range of gastrointestinal symptoms, including nausea, vomiting, abdominal pain, and diarrhea. Right lower quadrant (RLQ) abdominal pain is a common complaint for patients seeking care at emergency departments. In addition to appendicitis, the other possible causes include diverticular disease, epiploic appendagitis, Crohn's disease, or mesenteric lymphadenitis, among others. Mesenteric ischemia is an uncommon, but crucial cause of abdominal pain, necessitating early diagnosis and treatment. Herein, we report a 47-year-old man who presented to our emergency department complaining of RLQ abdominal pain following recovery from COVID-19. CT was performed due to concern for acute appendicitis. However, mesenteric thrombophlebitis and lymphadenitis in the ileocolic branch were noted on CT. His abdominal pain improved after receiving anticoagulation therapy. This case describes an uncommon etiology of RLQ abdominal pain that should be considered as a late complication of COVID-19.
ABSTRACT
DNA vaccination is a novel immunization strategy that possesses many potential advantages over other vaccine strategies. One of the major difficulties hindering the clinical application of DNA vaccination is the relative poor immunogenicity of DNA vaccines. Poly(methyl methacrylate) (PMMA) is a synthetic polymer approved by the Food and Drug Administration for certain human clinical applications such as the bone cement. In vivo, PMMA particles are phagocytosable and have the potential to initiate strong immune responses by stimulating the production of inflammatory cytokines. In this study, we synthesized a series of PMMA particles (PMMA 1-5) with different particle sizes and surface charges to test the feasibility of implementing such polymer particles for DNA vaccination. To our knowledge, this is the first report to show that the gene gun can deliver DNA vaccine by propelling PMMA particles mixed with plasmid DNA for cervical cancer. It was found that PMMA 4 particles (particle size: 460 +/- 160 nm, surface charge: +11.5 +/- 1.8 mV) stimulated the highest level of TNF-alpha production by macrophages in vitro and yielded the best result of antitumor protection in vivo. Therefore, our results possess the potential for translation and implementation of polymer particles in gene gun delivering DNA vaccination.
