Objective To observe the concentration of vancomycin and the changes of pharmacokinetic parameters in rabbit vitreous with endophthalmitis in different pathological conditions.Methods Eighty-one adult healthy rabbits were randomly divided into endophthalmitis with lens group (group A), aphakic endophthalmitis group (group B), aphakic endophthalmitis and vitrectomy group (group C), 27 rabbits in each group. The right eyes of all rabbits received intravitreal injection of 1 ml (10 mg/ml) vancomycin. Three rabbits from each group were sacrificed at 0.5, 2.0, 4.0, 6.0, 12.0, 24.0, 48.0, 72.0, 84.0 hours after the injection. The eyes were harvested to collect the vitreous. The vitreous concentrations of vancomycin in all the groups were detected by high performance liquid chromatography (HPLC-UV). The pharmacokinetic parameters including the area under the curve (AUC) of the concentration-time graph, clearance rate (CL), half-life period (t1/2) and peak concentration (Cmax) were calculated by 3p 97 pharmacokinetic software. Results The concentrations of vancomycin in the group A were always higher than the therapeutic drug levels after injection. In the group B and C, the concentrations of vancomycin remained significantly high at 0.5, 2.0, 4.0, 6.0 and 12.0 hours after injection, decreased quickly at 24 and 48 hours after injection, below the minimal inhibitory concentrations at 72 hours after injection. The differences were statistically significant among group A, B and C (t=4.968, 5.232;P＜0.05), but not statistically significant between group B and C (t=1.279, P＞0.05). The AUC were 15 790.61,7643.94, 7443.44 mu;g/(ml?h), CL were 0.063, 0.131, 0.134 ml/h, t1/2 were 13.49, 7.15, 6.93 hours and Cmax were 711.56, 648.45, 667.74 mu;g/ml in the group A, B and C, respectively. In the group A, the CL was lower (t=2.963, 3.097; P＜0.05) and t 1/2 was longer (t=3.315, 3.481; P＜0.01) than those in the group B and C, but there was no significant difference on Cmax (t=1.687,1.214;P＞0.05). Conclusion The pharmacokinetic parameters of vancomycin in rabbit vitreous with endophthalmitis varied between different pathological conditions
Epigenetic mechanisms influence gene expression and function without modification of the base sequence of DNA and may generateagenetic phenotype. Epigenetic modifications include DNA methylation, histone modifications, and deployment of noncoding RNA. There is growing evidence that epigenetic mechanisms could playacrucial role in the development of diabetic retinopathy (DR). Molecular biological methods which could maintain mitochondrial homeostasis through the regulation of epigenetic mechanisms may prevent the development of DR. Epigenetic-related treatment modalities will become the new direction of targeted therapy for DR.
Objective To evaluate the efficacy and safety of intravitreal bevacizumab (IVB) as a preoperative adjunct to vitrectomy for prevention of postoperative vitreous hemorrhage (VH) in proliferative diabetic retinopathy (PDR) patients.Methods This was a meta analysis of randomized controlled trials (RCT). A computerized search was conducted in the Medline, Embase, Cochrane Library, Chinese Biomedical Database and Chinese Journal Full text Database combined with manually searching of bibliographies of pertinent articles, journals and literature reference proceedings. RCT on IVB as a preoperative adjunct to vitrectomy for prevention of postoperative VH in PDR were selected according to inclusion and exclusion criteria. After the data extraction, methodological quality assessment of RCT that were included using the Jadad scale. The outcome measures included the incidence of postoperative VH, postoperative best corrected visual acuity (BCVA), the incidence of postoperative retinal reattachment and postoperative complications. The statistical analysis was performed by Stata/SE 11.2. The weighted mean difference (WMD) with 95% confidence interval (CI) was calculated for continuous variable, and odds ratio (OR) with 95% CI for dichotomous variable. Results In total, seven RCT that fulfilled the eligibility criteria were included in the metaanalysis involving 170 patients in IVB group and 161 patients in control group. According to the Jadad scale, one RCT scored 5 points, one RCT scored 3 points and the other 5 RCT scored 1 point. The results suggested that IVB group achieved lower incidence of postoperative VH than control group both within four weeks after surgery (OR=3.28, 95% CI: 1.58-6.82,P=0.00), and over four weeks after surgery (OR=2.51, 95% CI1.21-5.22,P=0.01). There was no significant differences in incidence of postoperative VH between IVB and control group either at postoperative 3 months (OR=2.52, 95% CI: 0.74-8.57,P=0.14), or at postoperative 6 months (OR=3.26, 95% CI: 0.50-21.45,P=0.22). The results suggested that IVB group achieved better postoperative BCVA than control group (WM1=0.29, 95% CI: 0.13-0.44,P=0.00), but no significant differences were found between IVB and control group on the incidence of postoperative retinal reattachment (OR=0.39, 95% CI:0.10ndash;1.59,P=0.19), postoperative retinal re-detachment (OR=2.36, 95% CI: 0.74- 7.56, P=0.15) and postoperative neovascular glaucoma (OR=1.47, 95% CI: 0.28ndash;7.71,P=0.65). Conclusions IVB as a preoperative adjunct to vitrectomy could prevent postoperative VH in PDR effectively, and be relatively safe. However, a high-quality, multicenter, large sample, long-term RCT is warranted to be further investigated.