The Role of Convalescent Plasma and Tocilizumab in the Management of COVID-19 Infection: A Cohort of 110 Patients from a Tertiary Care Hospital in Oman.

AIM: As Coronavirus Disease-2019 (COVID-19) pandemic continues to evolve, the search for safe and effective therapeutic interventions remain essential. METHODS: We conducted a retrospective cohort study on patients hospitalized with laboratory confirmed severe acute respiratory syndrome coronavirus-2 infection, comparing standard of care along with Convalescent Plasma with or without Tocilizumab (CP vs. CPT). RESULTS: A total of 110 patients were enrolled with an overall mean age of 50 ± 16 years. Patients on CPT were more likely to have had acute respiratory distress syndrome (77% vs. 42%; p < 0.001), sepsis (9.7% vs. 0; p = 0.036), chest X-ray abnormalities (71% vs. 44%; p = 0.004), intensive care unit admission (84% vs. 56%; p = 0.001) as well as being on mechanical ventilation (79% vs. 48%; p = 0.001). After CPT treatment, all measured inflammatory markers, except interleukine-6, showed an overall steady decline over time (all p-values <0.05) and the ventilatory parameters showed significant improvement of PaO2/FiO2 ratio from 127 to 188 within 7 days (p < 0.001). Additionally, 52% (32/62) of the patients had favorable outcome, either as improvement of ventilatory parameters or extubation within 14 days of hospitalization. However, mortality rate in those on CPT was higher than those who received CP alone (24% vs. 8.3%; p = 0.041). CONCLUSION: In patients with severe COVID-19 infection, using tocilizumab with convalescent plasma is associated with improvement in inflammatory and ventilatory parameters but no effect on mortality. These findings require validation from randomized clinical trials.

Effect of Food Simulating Agents on the Hardness and Bond Strength of a Silicone Soft Liner to a Denture Base Acrylic Resin.

STATEMENT OF THE PROBLEM: Bonding failure between acrylic resin and soft liner material and also gradual loss of soft liner resiliency over time are two impending challenges frequently recognized with a denture base embraced with a resilient liner. Since patients drink various beverages, it is crucial to assess the influences of these beverages on physical characteristics of soft liners. PURPOSE: This in vitro study envisioned to assess the influence of food simulating agents (FSA) on the hardness of a silicone soft liner by employing a Shore A durometer test and also evaluate its bond strength to a denture base resin by using tensile bond strength test. MATERIALS AND METHODS: To test the hardness of samples, 50 rectangular samples (40 mm × 10 mm × 3 mm) were prepared from a heat-polymerized polymethyl methacrylate (Meliodent). Mollosil, a commercially available silicone resilient liner, was provided and applied on the specimens following the manufacturer's directions. In order to test tensile bond strength, 100 cylindrical specimens (30 mm × 10 mm) were fabricated. The liners were added between specimens with the thicknesses of 3 mm. The specimens were divided into 5 groups (n=10) and immersed in distilled water, heptane, citric acid, and 50% ethanol. For each test, we used 10 specimens as a baseline measurement; control group. All specimens were kept in dispersed containers at 37ºC for 12 days and all solutions were changed every day. The hardness was verified using a Shore A durometer and the tensile bond strength was examined by an Instron testing machine at a cross-head speed of 5 mm/min. The records were analyzed employing one-way ANOVA, Tukey's HSD, and LSD tests. RESULTS: The mean tensile bond strength ± standard deviation (SD) for Mollosil was as follows for each group: 3.1 ± 0.4 (water), 1.8 ± 0.4 (citric acid), 3.0 ± 0.4 (heptane), 1.2 ± 0.3 (50% ethanol), and 3.8 ± 0.4 (control). The hardness values for each group were: 28.7 ± 2.11 (water), 33.2 ± 2.82 (citric acid), 39.2 ± 4.8 (heptane), 32.3 ± 3.56 (50% ethanol) and 22.2 ± 2.08 (control). Mean values for hardness indicated that all of the food simulating agents significantly increased hardness of the Mollosil soft liner compared to the control group (p<0.05). The results of tensile bond strength depicted that water and FSA decreased the bond strength of the soft liner -denture base resin compared to the control group and it was statistically significant (p<0.05). CONCLUSION: The food simulating agents could influence the mechanical properties of silicone soft liners; hence, clinicians should inform their patients concerning their possible adverse effects and complications.