Jiajun Xie

Smoking and risk of age-related cataract: a meta-analysis.

PURPOSE We conducted a meta-analysis to evaluate the relationship between smoking and age-related cataract (ARC). METHODS Eligible studies were identified via computer searches and reviewing the reference lists of the key articles. The summary relative risk ratio (RR) or odds ratio (OR) and 95% confidence interval (CI) were calculated. Study-specific risk estimates were pooled using a random-effects model. Meta-regression to assess heterogeneity by several covariates and subgroup analysis on ARC types were performed. RESULTS A total of 13 prospective cohort and eight case-control studies met our inclusion criteria. Ever smoking was statistically significantly associated with increased risk of ARC among cohort studies (OR 1.41, 95% CI 1.23-1.62) and case-control studies (OR 1.57, 95% CI 1.20-2.07). In subgroup analysis, ever smoking exhibited a positive relationship with nuclear cataract (NC; OR 1.66, 95% CI 1.46-1.89) and a marginally significant relationship with posterior subcapsular cataract (OR 1.43, 95% CI 0.99-2.07) in cohort studies. Similar results were found in case-control studies (NC OR 1.86, 95% CI 1.47-2.36; posterior subcapsular cataract OR 1.60, 95% CI 0.97-2.65). Current smokers were at higher risk of ARC than past smokers. No association between smoking and cortical cataract was observed. CONCLUSIONS The overall current literature suggests that smoking was associated with increased risk of ARC, especially NC. Further efforts should be made to confirm these findings and clarify the underlying biological mechanisms.

Simultaneous mechanical property and biodegradation improvement of wollastonite bioceramic through magnesium dilute doping.

The large-area bone defects in head (including calvarial, orbital, and maxillofacial bone) and segmental bone are attracting increased attention in a wide range of clinical departments. A key requirement for the clinical success of the bioactive ceramics is the match of the mechanical behavior of the implants with the specific bone tissue to be filled. This raises the question as to what design strategy might be the best indicators for the balance between mechanical properties and biological performances. Here we go beyond the traditional approaches that use phase conversion or biphasic hybrid; instead, we achieved a simultaneous enhancement of several mechanical parameters and optimalization of biodegradability by using a dilute doping of Mg in a single-phase wollastonite bioceramic. We show that the wollastonite ceramic can be rationally tuned in phase (α or β), mechanical strength (in compression and bending mode), elastic modulus (18-23GPa), and fracture toughness (>3.2MPam(1/2)) through the usage of Mg dopant introduced at precisely defined dilute concentrations (Mg/Ca molar ratio: 1.2-2.1%). Meanwhile, the dilute Mg-doped wollastonite ceramics are shown to exhibit good bioactivity in vitro in SBF but biodegradation in Tris is inversely proportional to Mg content. Consequently, such new highly bioactive ceramics with appreciable strength and toughness are promising for making specific porous scaffolds for enhancing large segmental bone defect and thin-wall bone defect repair.

Chitosan-modified, collagen-based biomimetic nanofibrous membranes as selective cell adhering wound dressings in the treatment of chemically burned corneas

Corneal chemical injury is a general but intractable ocular emergency, the sequelae of which are particularly challenging to treat. Human amniotic membrane (HAM) is one of the resources as a wound dressing for damaged corneal reconstruction, but the concerns related to the possible transmission of infectious diseases are the main drawbacks. Here we present a versatile method utilizing electrospinning and surface modification processes to develop optically highly transparent, microstructurally stable (>20 MPa in tensile strength in the wet state) biomimetic nanofibrous membranes. These membrane nanofibers, mainly consisting of a collagen-hyaluronate interior and a chitosan surface coating, showed superior mechanical and biological performances compared to HAM, and were favorable to the selective adhesion of epithelial cells (corneal, conjunctival) and fibroblasts. The alkali-burned corneal damage model in rats demonstrated that the biomimetic membranes could markedly improve re-epithelialization in corneal tissue within one week. Therefore, such bioactive multifunctional membranes may find widespread biomedical applications in wound healing and postoperative anti-adhesion in the near future.

A primary study of poly(propylene fumarate)–2-hydroxyethyl methacrylate copolymer scaffolds for tarsal plate repair and reconstruction in rabbit eyelids

Eyelid reconstruction includes anterior lamella reconstruction and posterior lamella reconstruction. As an important skeletal component of the posterior lamella, tarsal plates repair is the key issue for eyelid reconstruction. Presently, neither traditional surgery nor autograft/allograft has achieved satisfactory repair effects. Poly(propylene fumarate)-co-2-hydroxyethyl methacrylate (PPF-HEMA) networks with mass ratios of 1 : 0.5, 1 : 1 and 1 : 2 were synthesized and used as the tarsal substitute in this study. Their chemical compositions, swelling ability, and mechanical properties were characterized. Porous scaffolds were fabricated by a gelatin particle leaching method. The in vitro studies of cytotoxicity on human dermal fibroblasts (HDFs) and degradation demonstrated that PPF-HEMA scaffolds did not have noticeable cell cytotoxicity and their degradation rates correlated with the ratio of PPF to HEMA. The PPF-HEMA networks, with mass ratios of 1 : 1 and 1 : 2, and an ADM control were implanted in rabbits with tarsal plate defects for in vivo biocompatibility and degradation behavior evaluation. PPF-HEMA scaffolds provided satisfactory repair results with mild tissue response and biocompatibility to fibroblast growth and fibrous capsulation compared to the ADM control. The tissue compatible and biodegradable PPF-HEMA networks with elastic mechanical properties were proven to be a suitable candidate for tarsal repair.

Exposure rate of unwrapped hydroxyapatite orbital implants in enucleation surgery

Objective To document the long-term exposure rate of unwrapped coralline hydroxyapatite (HA) orbital implants and explore possible risk factors. Design This retrospective case series (May 2008–April 2013) reviewed the 234 patients with anophthalmia who underwent insertion of an unwrapped HA orbital implant by one of two different surgical closing techniques. Results Of the 234 cases, 151 underwent a rectus end-to-end suturing closure technique and 83 underwent a rectus orthotopic suturing closure technique. The time of follow-up ranged from 25 months to 69 months (mean 41.9 months). Implant exposure developed in 11 cases. Three in the rectus end-to-end suturing closure group (2.0%) and eight in the rectus orthotopic suturing closure group (9.6%). In the rectus end-to-end suturing technique, a crosswise fixation of vascularised rectus muscle tissue is formed across the front of the implant; in this group the incidence of implant exposure was reduced (OR=8.11, p=0.013). Prior ocular surgery was found to be a factor increasing the incidence of HA exposure (OR=2.73, p=0.032). Conclusions The placement of an unwrapped HA orbital implant with rectus end-to-end suturing in enucleation surgery was associated with a low rate of exposure in most cases. The end-to-end suturing creates a joint-like structure over the HA sphere, protecting the Tenons capsule and conjunctiva from its rough surface and reducing the risk of implant exposure. Prior ocular surgery may be another risk factor for HA exposure.