United States Medicare Reimbursement Trends for Glaucoma Procedures: 2000-2020.

PURPOSE: The purpose of this study is to investigate US Medicare reimbursement trends for common glaucoma procedures from 2000 to 2020. MATERIALS AND METHODS: Current Procedural Terminology codes for Glaucoma procedures in the US centers for Medicare and Medicaid Services database were used to conduct this economic analysis. Reimbursement data from the Physician Fee Schedule look-up tool from the Centers for Medicare and Medicaid Services were compiled for the selected procedures and compensation trends were investigated after adjusting for inflation in 2020 US dollars from the unadjusted data between 2000 and 2020. RESULTS: The average adjusted reimbursement for the analyzed procedures decreased by 20.5% [95% confidence interval (CI), -15.4% to -25.6%] over the 20-year period. On average, there was a 1.03% decrease in reimbursement rates per year (95% CI, -0.74% to -1.33%), with an adjusted compound annual growth rate of -1.35% (95% CI, -1.07% to -1.64%). The results show an overall declining rate in reimbursement for the glaucoma procedures analyzed in this study. CONCLUSIONS: The US Medicare reimbursement for glaucoma procedures in the United States showed a significant decline between 2000 and 2020. These findings may be relevant to understanding changing practice patterns for glaucoma care.

Coexpression of ABCB1 and ABCG2 in a Cell Line Model Reveals Both Independent and Additive Transporter Function.

Although overexpression of multiple ATP-binding cassette transporters has been reported in clinical samples, few studies have examined how coexpression of multiple transporters affected resistance to chemotherapeutic drugs. We therefore examined how coexpression of ABCB1 (P-glycoprotein) and ABCG2 contributes to drug resistance in a cell line model. HEK293 cells were transfected with vector-encoding full-length ABCB1, ABCG2, or a bicistronic vector containing both genes, each under the control of a separate promoter. Cells transfected with both transporters (B1/G2 cells) demonstrated high levels of both transporters, and uptake of both the ABCB1-specific substrate rhodamine 123 and the ABCG2-specific substrate pheophorbide a was reduced when examined by flow cytometry. B1/G2 cells were also cross-resistant to the ABCB1 substrate doxorubicin, the ABCG2 substrate topotecan, as well as mitoxantrone and the cell cycle checkpoint kinase 1 inhibitor prexasertib, both of which were found to be substrates of both ABCB1 and ABCG2. When B1/G2 cells were incubated with both rhodamine 123 and pheophorbide a, transport of both compounds was observed, suggesting that ABCB1 and ABCG2, when coexpressed, can function independently to transport substrates. ABCB1 and ABCG2 also functioned additively to transport the common fluorescent substrates mitoxantrone and BODIPY-prazosin, as it was necessary to inhibit both transporters to prevent efflux from B1/G2 cells. ABCG2 expression was also found to decrease the efficacy of the ABCB1 inhibitor tariquidar in B1/G2 cells. Thus, ABCB1 and ABCG2 can independently and additively confer resistance to substrates, underscoring the need to inhibit multiple transporters when they are coexpressed.

Limiting the Growth of Water-Soluble, Monolayer-Protected Quantum Dots.

The growth and solubility of quantum dots (QDs) are important factors that must be examined before these nanoparticles are incorporated into a variety of potential applications. In this work, monolayer-protected CdSe QDs surrounded by water-soluble thiols were prepared using various cadmium salts. The use of a variety of cadmium salts did not have a significant impact on the spectral properties of the CdSe QDs. CdSe QDs were synthesized at rather low temperatures (< 0°C), resulting in slow nanoparticle growth upon subsequent heating of the reaction mixture. The effect of multiple drying and redissolving cycles of the QD samples was examined. The effect of heating temperature on QD growth was studied, with more rapid nanoparticle growth associated with higher temperatures. The results show that QDs can be synthesized at low temperatures and their subsequent growth can be controlled during the heating process.