Cost-effective DNA methylation profiling by FML-seq.

Current methods for profiling DNA methylation require costly reagents, sequencing, and labor time. We introduce fragmentation at methylated loci and sequencing (FML-seq), a sequencing library protocol that greatly reduces all these costs. Relative to other techniques tested on the same human cell lines, FML-seq produces similar measurements of absolute and differential cytosine methylation at a fraction of the price. FML-seq enables inexpensive, high-throughput experimental designs for large-scale epigenetics research projects.

Fill levels, cost comparisons, and expulsion force requirements of commonly used topical ophthalmic steroids.

PURPOSE: To determine volume fill levels, estimated costs, and force expulsion requirements per bottle of topical ophthalmic steroids commonly used in the United States. SETTING: Tertiary care academic referral center. DESIGN: Prospective laboratory investigation. METHODS: 8 commercially available medications were tested: loteprednol 0.5%, loteprednol gel 0.5%, loteprednol gel 0.38%, difluprednate 0.05%, generic fluorometholone 0.1%, branded fluorometholone 0.1%, generic prednisolone 1.0%, and branded prednisolone 1.0%. 10 bottles of each medication were tested. A double-blinded method was used to measure actual bottle fill volume and number of drops dispensed per bottle. The total perioperative cost per drop was calculated for each medication using a mean cash price. Force requirements were measured using a customized force gauge apparatus. Formulations were compared using Kruskal-Wallis 1way analysis of variances. RESULTS: All formulations were able to cover postoperative periods commensurate with commonly used dosing regimens for cataract surgery. All medications had greater than sticker volume. Loteprednol 0.5% suspension and branded fluorometholone had the highest and lowest number of drops among the medications tested, respectively. Loteprednol 0.38% gel was the most expensive medication, whereas generic prednisolone 1.0% was the least expensive. Gel and branded formulations of ophthalmic steroids required less expulsion force compared with other tested formulations. CONCLUSIONS: Volume fill levels, patient-incurred costs, and expulsion force requirements per bottle of topical steroid medications vary widely. Clinicians may wish to consider these findings when determining their perioperative prescribing regimen.