Metformin loaded injectable silk fibroin microsphere for the treatment of spinal cord injury.

The repair of spinal cord injury is a great challenge in clinical. Improving the microenvironment of the injured site is the key strategy for accelerating axon regeneration and synaptic formation. Herein, a kind of silk fibroin microspheres functionalized by metformin through dopamine was developed using water-in-oil emulsification-diffusion method and surface modification technique, and the effect on cortical neuron was evaluated. The results showed that the microspheres showed a uniform size distribution with the diameter of around 60 µm and a concave structure. Moreover, the microspheres possessed good injectability and stability. In addition, the metformin could be successfully immobilized in the silk fibroin microspheres. The cell culture results displayed that the growth and morphology of cortical neurons on the microspheres with metformin concentration of 5 mg/mL and 10 mg/mL were obviously better than that on other samples. Notably, the spread area of single cortical cell on silk fibroin microspheres was increased with the ascending metformin concentration. Therefore, the results indicated that the metformin loaded silk fibroin microsphere could obviously improve the growth and spreading behavior of cortical neuron. The study may provide an important experimental basis for the development of drug loaded injectable biomaterials scaffolds for the treatment of spinal cord injury and have great potential for spinal cord regeneration.

A Technique to Reduce Incidence of Opaque Bubble Layer Formation During LASIK Flap Creation Using the VisuMax Femtosecond Laser.

PURPOSE: To identify risk factors for opaque bubble layer (OBL) formation and compare the incidence of OBL using a cone modification technique versus the original technique for LASIK flap creation using the VisuMax laser (Carl Zeiss Meditec, Jena, Germany). METHODS: This retrospective study examined videos of flap creation using the VisuMax laser to identify OBL occurrence. Eyes were divided into three groups: eyes where OBL occurred using the original technique (OBL group), eyes where OBL did not occur using the original technique (no OBL group), and eyes in which the cone modification technique was used for LASIK flap creation (larger flap diameter) (cone modification technique group). Preoperative measurements including simulated keratometry (flat and steep) values, white-to-white distance (WTW), pachymetry, patient age and gender, amount of correction, flap parameters, energy setting, corneal hysteresis, and corneal resistance factor were analyzed to identify parameters with statistical difference between the OBL and no OBL groups. Incidence of OBL was compared between the original and cone modification techniques. RESULTS: OBL incidence was significantly lower with the cone modification technique (7.6%; 7 of 92 eyes) than with the original technique (28.8%; 34 of 118 eyes) (Fisher's exact test, P = .0009). Factors identified with a significant difference between eyes with and without OBL using the original technique were: corneal thickness (OBL: 561.2 µm, no OBL: 549.6 µm, P = .0132), WTW diameter (OBL: 11.6 mm, no OBL: 11.9 mm, P = .0048), corneal resistance factor (OBL: 10.4 mm Hg, no OBL: 9.6 mm Hg, P = 0.0329), and corneal astigmatism (OBL: 0.80 diopter, no OBL: 1.00 diopter, P = .0472) CONCLUSIONS: Less astigmatic, thicker, denser, and smaller corneas increased the risk of OBL using the original technique for flap creation. The cone modification technique was associated with lower risk of OBL formation, even in eyes with significant risk factors for OBL using the original technique. [J Refract Surg. 2017;33(9):584-590.].

[The relationship between calcaneus bone mineral density and metabolic syndrome].

OBJECTIVE: To evaluate the association between calcaneus bone mineral density (BMD) and metabolic syndrome (MS). METHODS: A cross-sectional study was carried out in 5 552 subjects with 1 987 men and 3 565 women (age:40-87 years old). MS was defined according to Chinese Diabetes Society criteria. BMD was assessed by quantitative ultrasound. RESULTS: The proportion of MS was 29.0% in male and 24.4% in female. There were no differences in BMD between MS and non-MS subjects in both genders. Linear trend analysis displayed that BMD was positively associated with the increase of MS components in post-menopausal women after adjustment of age, ALT, creatinine and exercises (P < 0.05). Moreover, multiple regression analysis showed that BMD was inversely correlated with age (ß = -0.034, P < 0.001) and positively correlated with BMI (ß = 0.046, P = 0.001) , TG (ß = 0.066, P = 0.034) and systolic blood pressure (SBP) (ß = 0.007, P = 0.039) in post-menopausal women with MS. CONCLUSIONS: BMD tended to increase with the numbers of MS components in post-menopausal women. It was positively correlated with BMI, TG and SBP in postmenopausal women with MS.

Minor influence of sub-bowman keratomileusis on the posterior corneal surface at early stage.

PURPOSE: To evaluate the changes in posterior corneal surface (Q value and elevation) measured with Pentacam after femtosecond laser assisted Sub-Bowman Keratomileusis (SBK). METHODS: The Q values and elevation of posterior corneal surface were determined in 166 myopic/myopic astigmatism eyes of 88 patients using Scheimpflug imaging (Pentacam; Oculus, Wetzlar, Germany), which estimates asphericity and elevation for several areas of cornea analysed (Q value: 6, 7, 8 and 9 mm; elevation: 2, 4, 6 and 8 mm) before 1 and 3 months after SBK. The correlations between the changes of Q value or elevation and the mean preoperative spherical equivalent (SE), central corneal thickness (CCT), central ablation depth (AD), estimated residual bed thickness (RBT) and RBT/CCT ratio were investigated. RESULTS: Meridian and area differences in Q of posterior surface have been showed. Two major meridians (horizontal/vertical) present the change of significant negative direction before surgery (all p < 0.001), but the alteration of significant positive direction for all post-SBK follow-up visits (all p < 0.05). There was no statistically significant difference in posterior elevation at 2 mm zone (horizontal meridian: p = 0.439; vertical meridian: p = 0.233). Compared with preoperation, minor but significant forward displacements were found in posterior elevation at 4 and 6 mm areas of cornea analyzed (horizontal meridian: all p < 0.001; vertical meridian: p < 0.001, p = 0.024, respectively). However, posterior elevation in two meridians (horizontal/vertical) at 8 mm region was displayed significant backward shift (p = 0.001, p < 0.001, respectively). The Pearson correlation test showed no significant correlation between the changes in the Q values and elevation data in vast majority of areas of cornea analyzed and the SE, CCT, AD, RBT, and RBT/CCT ratio at 1 and 3 months after surgery (all p > 0.05). CONCLUSIONS: The posterior corneal surface showed central flattening and peripheral steepening at early stage post-SBK. To combine the asphericity with the elevation of the posterior corneal surface can overall and accurately understand the posterior corneal shape and its variations after refractive surgery.

[Inhibitory effect of diclofenac sodium on the proliferation of rabbit corneal epithelial cells in vitro].

PURPOSE: To investigate the inhibitory effect of diclofenac sodium on rabbit corneal epithelial cells (RCECs) in vitro and explore its pharmacological mechanism. METHODS: The fresh rabbit cornea was cultured to obtain the primary RCECs, and RCECs of passage 2 were used in this research. The cells were divided into experimental groups, the cells in which were incubated with different concentrations (18.18, 27.27, 36.36, 45.45, 54.55 µg/ml) of diclofenac sodium, and control group. The effect of diclofenac sodium on the proliferation of cells was measured by methyl thiazolyl thiazolium (MTT) assay 24, 48 and 72 h after incubation. While the RCECs were divided into experimental groups, the cells in which were incubated with 9 and 12.5 µg/ml diclofenac sodium, and control group. The cell cycle and apoptotic rate were observed by flow cytometer. RESULTS: MTT assay showed that diclofenac sodium had obvious inhibitory effect on RCECs, and the inhibition rate was increasing along with the increasing concentration of diclofenac sodium and the incubation time(P<0.05). Flow cytometer showed that after incubation with diclofenac sodium, the cells in G0/G1 phase were obviously increased, and the apoptosis cusp and apoptotic rate were increased. CONCLUSION: Diclofenac sodium exerts significant inhibitory effect on RCECs in a dosage-dependent manner, and it may function by inducing cell apoptosis and ceasing cell cycles.

[An analysis about the safe range of thickness of the residual corneal stroma bed after LASIK].

OBJECTIVE: To ascertain the safe range of thickness of the residual corneal stroma bed and the length of stable time after LASIK operation. METHODS: Two hundred and twenty seven eyes were randomly selected from cases treated with LASIK in 2000. The posterior curvature of cornea was measured by Obscan II preoperatively and 1, 2, 3, 6 months, 1 year and 2 year postoperatively. These data were compared and analyzed. RESULTS: Ectasia of central corneal posterior surface was detected at different degrees in all cases at the early postoperative period after LASIK. Ectasia was more prominent in eyes with thinner corneal stroma bed (< 300 microm). In eyes with thicker corneal stroma, ectasia remained stable or reverting obviously during the first year. The posterior curvature of cornea had no significant difference between 1 year and 2 year after operation in all cases. CONCLUSIONS: Ectasia of corneal posterior surface presents in the early postoperative period after LASIK. It is safer to reserve more than 300 microm of the corneal stroma bed. The posterior curvature of cornea of all cases remains stable after one year postoperatively.