Abstract: Clarifying the relationship between the molecular structure of ion-exchange resins and the elution of carbohydrates is essential for analyses using high-performance liquid chromatography (HPLC). From the perspective of novel resin development, we evaluated the effect of the number of methylene groups in the functional chain of the porous polymer shell on carbohydrate separation. Core-shell ion-exchange resins with a monomer weight ratio of 20:80 (denoted as St-80) were synthesized with a constant cross-linking degree of 55%. The number of methylene groups in the functional chain of the porous polymer shell was varied from two to six for analyses of carbohydrate separation performance under strong alkaline conditions. A mixture of inositol, glucose, fructose, and sucrose was separated using a 0.10 or 0.15 mol/L NaOH eluent at flow rates of 0.3–0.7 mL/min. The retention times were compared among St-80 variants with different numbers of methylene groups in the porous layer. As the number of methylene groups increased, the retention times of each carbohydrate for St-80(Me:4) at flow rates of 0.3–0.7 mL/min with 0.10 mol/L NaOH eluent increased slightly. The theoretical plate numbers of glucose and fructose at flow rates of 0.5 and 0.7 mL/min decreased as the number of methylene groups decreased from six to two. These results suggest that St-80 core-shell ion-exchange resins are highly efficient for carbohydrate analyses. Their suitability for strongly alkaline conditions allows their effective use in electrochemical detection.Abstract: Clarifying the relationship between the molecular structure of ion-exchange resins and the elution of carbohydrates is essential for analyses using high-performance liquid chromatography (HPLC). From the perspective of novel resin development, we evaluated the effect of the number of methylene groups in the functional chain of the porous polymer sh...Show More
Abstract: Cyclooxygenase 2 (COX-2) is highly induced during coronavirus (COVID-19) infection. We believe selective COX-2 inhibition shall be a valuable tool to reduce virus toxicity in related patients. Dexamethasone, one of potent selective COX-2 inhibitors, has been used successfully in the standard care for patients with COVID-19. Given that low-dose dexamethasone inhibits thrombosis, reduces the death rate by one-third in patients with severe COVID, and is in the same dose range for effective COX-2 inhibition, we believe that vascular COX-2 is coupled to thrombosis and it is critical to selectively inhibit COX-2 to avoid tissue damage and death in patients. We should take efforts to replace dexamethasone with non-steroidal selective COX-2 inhibitors such as celecoxib (Celebrex) and etoricoxib (Arcoxia) to avoid steroidal side effects. For detailed in vivo COX-2 analysis in the vasculature and other organs, we should leverage tools such as conditional knockout animal models to avoid cardiovascular congestion caused by renal COX-2 disruption. Detailed preclinic and clinic studies will help to develop selective COX-2 inhibition therapies for consistent applications across the population.
Abstract: Cyclooxygenase 2 (COX-2) is highly induced during coronavirus (COVID-19) infection. We believe selective COX-2 inhibition shall be a valuable tool to reduce virus toxicity in related patients. Dexamethasone, one of potent selective COX-2 inhibitors, has been used successfully in the standard care for patients with COVID-19. Given that low-dose dexa...Show More