Efficient DNA/RNA extraction from tarsal plates by SK mill, a freeze-crush apparatus.

The tarsal plate is an eyelid tissue that maintains lid structure from inside the upper/lower eyelids, and it surrounds the meibomian glands and supports their unique secretion mechanism. Sebaceous carcinoma, a malignant eyelid tumour, can sometimes develop from the meibomian glands and is usually excised together with the tarsal plate during surgery, so the tarsal plate serves as a control research tissue. However, since the plate is thick, hard and heterogeneous with few cells, obtaining enough genomic DNA and/or total RNA is often difficult. Therefore, we attempted to establish an efficient protocol to obtain DNA and RNA simultaneously by comparing the combinations of homogenization (mortar/pestle, pellet pestle or SK mill) and purification (organic solvent or spin column) methods using rabbit tarsal plates. Based on the yield, quality and hands-on time, the SK mill and spin column was found to be the most efficient combination. We then applied the established protocol to extract DNA/RNA from six human tarsal-plate samples and succeeded in generating high-quality exome and transcriptome datasets via a next-generation sequencer with sufficient coverage and meibomian gland-specific expression of representative genes, respectively. Our new findings will provide ideal reference data for future genetic and gene-expression studies of sebaceous carcinoma.

Risk factors for intraocular pressure elevation during the early period post cataract surgery.

PURPOSE: To assess the risk factors for intraocular pressure (IOP) elevation during the early period post cataract surgery. STUDY DESIGN: Retrospective study. METHODS: This study involved 1587 eyes that underwent cataract surgery at the Baptist Eye Institute, Kyoto, Japan between April 2020 and May 2021. In all subjects, risk factors for early postoperative IOP elevation (i.e., an increase of IOP of 10 mmHg or more at 1-day postoperative compared with that at baseline, or a postoperative IOP of 28 mmHg or more) were analyzed by multivariate logistic regression analysis. RESULTS: Of the 1587 treated eyes in this study, 100 (6.3%) experienced early-postoperative IOP elevation. Of those 100 eyes, 78.0% were men, 27.0% had an axial length (AL) of ≥ 26.5 mm, 23.0% had a history of glaucoma treatment, 11.0% had poor mydriasis and 10.0% had intraoperative floppy iris syndrome (IFIS). Multivariate analysis findings revealed that male [odds ratio (OR) 4.36; 95% confidence interval (CI) 2.63-7.23; P < 0.001], AL of ≥ 26.5 mm (3.11; 1.83-5.30; P < 0.001), a history of glaucoma treatment (2.83; 1.63-4.91; P < 0.001), poorly mydriasis (2.63; 1.16-6.01; P = 0.02), IFIS (4.37; 1.78-10.74; P = 0.001) and baseline high IOP (1.09; 1.01-1.18; P = 0.03) were associated with increased IOP during the early period post cataract surgery. CONCLUSIONS: The findings in this study reveal that male sex, high myopia, a history of glaucoma treatment, poor mydriasis, IFIS and baseline high IOP are risk factors for IOP elevation during the early period post cataract surgery.