Seaweeds from the genus Porphyra play a big economic role in seaweed aquaculture, mainly in Asia. In Europe, resources are put towards seaweed cultivation, but without attention to the Porphyra species which is also native to Europe. Different nomenclature and specifications are used to describe Porphyra, due to taxonomical reclassification and difficult phenotypical identification. Abiotic & biotic together with seasonal factors make for major variance in chemical compositions that are reported. This is also fueled by differences in chemical analytical methods and procedures followed. Combining taxonomical challenges, variance due to seasonal factors and differences in analysis, overviewing published research on Porphyra constituents such as protein, polysaccharides and fatty acids is warranted. Within this review, cellular consitutents found in Porphyra are discussed, including proteins, polysaccharides, fatty acids and mycosporine-like amino acids (MAA’s). MAA's are considered amongst the strongest UV-photoprotectants found in nature and feature possible applications in cosmetics. As global interest in seaweeds as food, feed and industrial resource is emerging, opportunities for Porphyra constituents is rising.
BACKGROUND: Estimates for dead space ventilation have been shown to be independently associated with an increased risk of mortality in the acute respiratory distress syndrome and small case series of COVID-19-related ARDS.METHODS: Secondary analysis from the PRoVENT-COVID study. The PRoVENT-COVID is a national, multicenter, retrospective observational study done at 22 intensive care units in the Netherlands. Consecutive patients aged at least 18 years were eligible for participation if they had received invasive ventilation for COVID-19 at a participating ICU during the first month of the national outbreak in the Netherlands. The aim was to quantify the dynamics and determine the prognostic value of surrogate markers of wasted ventilation in patients with COVID-19-related ARDS.RESULTS: A total of 927 consecutive patients admitted with COVID-19-related ARDS were included in this study. Estimations of wasted ventilation such as the estimated dead space fraction (by Harris-Benedict and direct method) and ventilatory ratio were significantly higher in non-survivors than survivors at baseline and during the following days of mechanical ventilation (p < 0.001). The end-tidal-to-arterial PCO2 ratio was lower in non-survivors than in survivors (p < 0.001). As ARDS severity increased, mortality increased with successive tertiles of dead space fraction by Harris-Benedict and by direct estimation, and with an increase in the VR. The same trend was observed with decreased levels in the tertiles for the end-tidal-to-arterial PCO2 ratio. After adjustment for a base risk model that included chronic comorbidities and ventilation- and oxygenation-parameters, none of the dead space estimates measured at the start of ventilation or the following days were significantly associated with 28-day mortality.CONCLUSIONS: There is significant impairment of ventilation in the early course of COVID-19-related ARDS but quantification of this impairment does not add prognostic information when added to a baseline risk model.TRIAL REGISTRATION: ISRCTN04346342. Registered 15 April 2020. Retrospectively registered.
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