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Purpose: To investigate the feasibility of percutaneous radiofrequency (RF) ablation to occlude the thoracic duct (TD) in a swine model with imaging and histologic correlation.Materials and Methods: Six swine underwent TD RF ablation. Two terminal (4 hours, 1 open and 1 percutaneous) and 4 survival (30 days, all percutaneous) studies were performed. Two 20-gauge needles were placed adjacent to the TD under direct visualization after right thoracotomy or under fluoroscopic guidance using a percutaneous transabdominal approach after intranodal lymphangiography. RF electrodes were advanced through the needles, and ablation was performed at 90°C for 90 seconds. Lymphangiography was performed, and the TD and adjacent structures were resected and examined microscopically at the end of each study period.Results: Four of 6 subjects survived the planned study period and underwent follow-up lymphangiography. Two subjects in the survival group were euthanized early-1 after developing an acute chylothorax and 1 because of gastric volvulus 14 days after ablation. Occlusion of the targeted TD segment was noted on lymphangiography in 3 of the 4 remaining subjects (2 acute and 1 survival). Histology 4 hours after RF ablation demonstrated necrosis of the TD wall and hemorrhage within the lumen. Histology at 14 and 30 days revealed fibrosis with hemosiderin-laden macrophages replacing the ablated TD. Collagen degeneration within the aortic wall involving a maximum of 60% thickness was noted in 5 of the 6 subjects.Conclusions: Percutaneous RF ablation can achieve short-segment TD occlusion. Further study is needed to improve safety and demonstrate clinical efficacy in treating TD leaks. [ABSTRACT FROM AUTHOR]

Attempts to explain the colour blends described by Democritus and Plato in terms of the pigments used by painters fail. Scholars as a rule have refrained from tackling this problem. The present paper, taking up a suggestion of Walter Kranz, argues that the colour blends of these two philosophers pertain to a broad spectrum of natural phenomena and processes.

Non-specific protective effects of certain vaccines have been reported, and long-term boosting of innate immunity, termed trained immunity, has been proposed as one of the mechanisms mediating these effects. Several epidemiological studies suggested cross-protection between influenza vaccination and COVID-19. In a large academic Dutch hospital, we found that SARS-CoV-2 infection was less common among employees who had received a previous influenza vaccination: relative risk reductions of 37% and 49% were observed following influenza vaccination during the first and second COVID-19 waves, respectively. The quadrivalent inactivated influenza vaccine induced a trained immunity program that boosted innate immune responses against various viral stimuli and fine-tuned the anti-SARS-CoV-2 response, which may result in better protection against COVID-19. Influenza vaccination led to transcriptional reprogramming of monocytes and reduced systemic inflammation. These epidemiological and immunological data argue for potential benefits of influenza vaccination against COVID-19, and future randomized trials are warranted to test this possibility., Competing Interests: The authors have declared that no competing interests exist.