Ten-year observation of corneal densitometry and associated factors following small incision lenticule extraction.

AIM: To investigate the long-term changes of corneal densitometry (CD) and its contributing elements after small incision lenticule extraction (SMILE). METHODS: Totally 31 eyes of 31 patients with mean spherical equivalent of -6.46±1.50 D and mean age 28.23±7.38y were enrolled. Full-scale examinations were conducted on all patients preoperatively and during follow-up. Visual acuity, manifest refraction, axial length, corneal thickness, corneal higher-order aberrations, and CD were evaluated. RESULTS: All surgeries were completed successfully without complications or adverse events. Ten-year safety index was 1.17±0.20 and efficacy 1.04±0.28. CD value of 0-6 mm zones in central layer was statistically significantly lower 10y postoperatively, compared with preoperative values (0-2 mmΔ=-1.62, 2-6 mmΔ=-1.24, P<0.01). There were no correlations between CD values and factors evaluated. CONCLUSION: SMILE is a safe and efficient procedure for myopia on a long-term basis. CD values get lower 10y postoperatively, whose mechanism is to be further discussed.

[Assessing abundance and specificity of different types of sgRNA targeting miRNA precursors].

CRISPR/Cas technology enables efficient and specific editing the genome. Since different bacterial sources or artificially modified Cas9, as well as Cpf1 and other nucleases, recognize different PAMs (protospacer adjacent motifs), different gene editing nucleases may use different types of sgRNAs (small guide RNA). MicroRNAs (miRNAs) are a class of regulatory small non-coding RNAs. To determine whether specific targets for sgRNAs in miRNA precursor exit, the abundance and specificity of 11 different types of sgRNA targeting 28 645 miRNA precursors were analyzed in the present study using the CRISPR-offinder, a bioinformatics software developed in our own laboratory. The CRISPR/Cas9 lentivirus technology was used to target the miR-302/367 cluster in a porcine cell line, and its knockout efficiency for the miRNA target was evaluated. The results show that there are about 8 different types of sgRNAs that can target individual miRNA precursors. By assessing the off-target effect, only 18.2% of the sgRNAs showed high specificity for targeting the porcine miRNA precursors. Lastly, using the miR-302/367 cluster target as an example, we showed that the CRISPR/Cas9 lentivirus technology was 40% efficient in successfully establishing correct knockout of the target miRNA in the porcine cell line. This present study provides an important resource for the use of CRISPR/Cas technology to target miRNAs for knockout studies.

[Bone mineral density decreased is a high risk factor for uncemented acetabular cups migration in female total hip arthroplasty patients].

OBJECTIVE: To investigate the decrease of bone mineral density in female patients, effects on acetabular displacement. METHODS: From October 2013 to November 2015, a total of 34 patients underwent total hip replacement in the Department of orthopedics, the Third Affiliated Hospital of Zunyi Medical College. The two groups of patients were female and the patients were treated with hip osteoarthritis. Based on the lowest value of preoperative dual energy X-ray bone mineral density (DXA), the patients were divided into normal group and low bone mineral density(-3.5<=T<=-1). There were 10 patients in the normal group, ranging in age from 55 to 64 years old, with an average of (58.00±4.22) years old. There were 24 patients in the low bone density group, ranging in age from 58 to 72 years old, with an average age of (65.71±8.19) years old. All the patients received a THA implant with ceramic-on-ceramic bearings(Depuy America). The lining system was Pinnacle cup. During the operation, the acetabular cup was maintained at abduction 45 degree and anteversion 15 degree. Analysis (RSA) of acetabular components in 3, 6, 12, and 24 months after surgery. RESULTS: There was a statistically significant difference in cup migration between patients with normal BMD and those with low BMD. At 3 months, compare to the normal group, the low bone mineral density (BMD) occurred in the X axis (95% confidence interval, 0.01 to 0.31; P=0.006) and Y (95% confidence interval 0.20 to 0.39; P=0.003). The initial rotation occurs in a separate Z axis(95% confidence interval -0.26 to 0.81; P=0.006). CONCLUSIONS: It has produced that increaseed migration of uncemented cups in female patients with low systemic BMD in 3 months after surgery.