Cross-linking of human amniotic membrane by ultraviolet A-riboflavin / 中华实验眼科杂志

BackgroundStudies confirmed that ultraviolet A (UVA)- riboflavin photodynamic therapy can control keratoconus progresses by altering the physicochemical property of cornea.The collagen components of amniotic membrane transplantation is similar to that of cornea and amniotic membrane transplantation has been widely used to ocular surface reconstruction.However,the study on UVA riboflavin-induced-collagen crosslinking for amniotic tissue is less now.ObjectiveThis study was to investigate the role of UVA-riboflavin on frozen-preserved human amniotic membrane.Methods Human amnions were obtained in informed consent and prepared into 2 mm×15 mm pieces and were then divided into 4 groups using lottery method and 6 pieces for each group.The first 3 groups were treated with the photosensitizer riboflavin and UVA-irradiation ( wavelength:370 nm ; irradiation energy:1,2 or 3 mW/cm2,distance:10 mm) for 30 minutes,and the untreated fourth group was as control group.Biomechanical stress-strain test was performed using a microcomputer-controlled biomaterial tester and the stress(mN) was recorded when the strains were set to 5％,10％ and 15％.The 7 mm diameter of human amniotic membrane pieces were trephined and divided into 4 groups(5 pieces for each group) with the treated method as mentioned above,and then the buttons were exposed to 0.1％ collagenase Ⅰ solution.The transparency was scored and the complete dissolving time was record.In histological evaluation,three groups (3 pieces for each group) of human amniotic membranes were treated using UVAriboflavin(3 mW/cm2),0.1％riboflavin,normal saline for 30 minutes respectively and examined under the transmission electron microscopy.This study was performed under the permission of the Ethic Commission of Beijing Tongren Hospital.ResultsWhenthestrainwas 5％,10％,15％,thestressof controlgroupand1,2,3 mW/cm2UVA group were statistically signifcantly different ( F =3.411,P =0.037; F =9.927,P =0.001;F=11.118,P=0.000).The tensile strength of human amniotic membrane cross-linked with UVA-riboflavin was statistically significantly increased in comparison to the control group (P＜0.05 ),and the tensile strength of human amniotic membrane became stronger as UVA power increased.The complete dissolve time was (8.6± 1.8 ) hours for the control group,(39.6± 2.3 ) hours for 1 mW/cm2 UVA group,(71.4±0.9 ) hours for 2 mW/cm2 UVA group,(78.8± 1.8 ) hours for 3 mW/cm2 UVA group,showing the enhanced anti-enzyme ability of human amniotic membrane after cross-linking(P＜0.01 ).The collagen density in the UVA-riboflavin treated group was increased,the connection among the collagen fibers as well as between the stroma and the epithelium became tighter than those of control group.ConclusionsCollagen cross-linking with UVA-riboflavin make the biomechanical strength and enzymatic resistance of human amniotic membrane enhance and ultrastructure change of human amniotic membrane.

Cross-sectional investigation of visual impairing diseases in Shanghai blind children school / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The control of blindness in children is a high priority within the VISION 2020 initiative. To determine the causes of severe visual impairment and blindness in children from Shanghai Blind Children School (SBCS) can provide useful information on childhood blindness in Shanghai.</p><p><b>METHODS</b>A cross-sectional investigation of students in SBCS was conducted in May 2010. The World Health Organization/Prevention of Blindness (WHO/PBL) eye examination record system for children with low vision and blindness was used. The results were further compared with the findings of two previous investigation studies conducted in 1986 and 2004, respectively in SBCS.</p><p><b>RESULTS</b>Of the 146 children observed, 80 children (54.8%) were blind (best corrected best visual acuity less than 0.05), 27 children (18.5%) had severe visual impairment (best corrected visual acuity less than 0.1 but better than or equal to 0.05), and 34 children (23.3%) had moderate visual impairment (best corrected visual acuity less than 0.3 but better than or equal to 0.1). The major affected anatomic sites in the 107 children with severe visual impairment and blindness (SVI/BL) were retina (47.7%), whole globe (16.8%), optic nerve (13.1%) and lens (9.3%). The leading causes of SVI/BL were retinopathy of prematurity (ROP, 25.2%), followed by retinal dystrophy (15.9%), optic nerve atrophy (9.3%) and microphthalmos (9.3%). The two leading etiologic categories of SVI/BL were perinatal/neonatal (36.4%) and congenital/hereditary groups (29.0%). The leading cause of moderate visual impairment was aphakia after cataract surgery (congenital cataract, 44.1%). Compared with the findings in two previous investigations in SBCS, the proportion of ROP in visual impairing diseases increased, while the proportion of disorders of the lens (cataract and aphakia) significantly decreased.</p><p><b>CONCLUSIONS</b>The leading cause of childhood blindness in SBCS nowadays is ROP. It is projected that without improvement in perinatal medical care that ROP will continue to be a major cause of childhood blindness.</p>

Epidemiology of pterygium in aged rural population of Beijing, China / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Pterygium is a common ophthalmic disease and an important public health problem. It may be affected by many factors such as age, gender, ultraviolet radiation exposure, and time spent outdoors. This study aimed to investigate the prevalence of pterygium and evaluate the risk factors for the development of pterygium in the aged rural population of Beijing.</p><p><b>METHODS</b>The investigation is a population-based cross-sectional study. Participants from 198 villages of 13 suburban districts, aged 55 - 85 years old, were invited to complete a medical record, and 37 067 individuals were taken external ocular and fundus photos at Beijing ocular disease survey in 2008-2009. The information was uploaded by Internet and diagnosed with stages and grades by ophthalmological specialists. The prevalence, stages and grades of pterygia were observed.</p><p><b>RESULTS</b>Of the 37 067 individuals, 1395 (3.76%) had pterygium. There was a significantly higher prevalence in male (5.13%) than in female (3.17%, P = 0.000). The prevalence rate increased obviously with ages (chi(2) = 7.939, P = 0.019) in rural Beijing. The average prevalence of 5.91% in Daxing and Fangshan districts with low latitude and low precipitation was significantly higher than that in Miyun and Huairou districts with high latitude and deep precipitation (3.17%, P = 0.000). The majority of the pterygia (43.5%) were in active stage and 46.5% pterygia involved pupil area corneas.</p><p><b>CONCLUSIONS</b>There is a statistically significant association between latitude and precipitation of habitation region and pterygium formation. Solar radiation, especially ultraviolet exposure represents a significant environment hazard to pterygium development.</p>

Effect of topical application of terbinafine on fungal keratitis / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Fungal keratitis is a rare but serious corneal disease that may result in loss of vision. The poor prognosis might be due to limited treatment option. This study aimed to evaluate the clinical efficacy of 0.25% terbinafine eye drops comparing with 5% natamycin suspension on fungal keratitis.</p><p><b>METHODS</b>A retrospective clinical trial was performed on 90 patients presenting with direct smear and/or culture positive fungal keratitis at Beijing Tongren Hospital, Beijing, China from January 2006 to May 2008. Corneal ulcers were categorized as mild or severe. Forty-five patients were treated with topical terbinafine and the next 45 cases received topical natamycin hourly.</p><p><b>RESULTS</b>Filamentous fungi were found in corneal scrapings among all 90 cases. Fungal cultures were positive in 64 patients (71%). Species of Fusarium and Aspergillus were the principal isolates. Forty (89%) patients showed favorable response to terbinafine, while forty-two (93%) patients exhibited favorable response to natamycin (P > 0.05). The mean course of treatment was significantly showed in the terbinafine treatment group than natamycin group ((26.5 +/- 11.2) days versus (19.3 +/- 6.4) days; P < 0.05). In terbinafine group, twenty patients with ulcers smaller than 4 mm had favorable outcome, while 20 of 25 patients with ulcers more than 4 mm in diameter had favorable response (P < 0.05). Twenty-seven patients with depth of infiltration less than half of stroma thickness had favorable response to terbinafine, while 13 of 18 patients with depth of infiltration more than half of stroma responded to terbinafine. This difference was statistically significant (P < 0.05).</p><p><b>CONCLUSIONS</b>Our findings suggest that topical terbinafine is an effective antifungal drug for the management of filamentous mycotic keratitis, particularly in cases with smaller and shallower ulcers. Its mean duration of treatment was longer than natamycin.</p>

Genetic typing and antibiotic susceptibility testing of strains from pseudomonas aeruginosa keratitis patients / 眼科

Objective To study the characteristics of Genetic typing and the antibiotic susceptibility testing of strains from Pseudomonas aeruginosa keratitis patients.Design Experimental study,Participants 23 eyes of 23 patients of Pseudomonas aeruginosa keratitis.Methods The genomic was extracted and amplified with PCR.The PCR products were purified and sequenced.The results were registered in MIST web Antibiotic susceptibility testing were performed in theses strains,Main Outcome Measures Sequence types and antibiotic susceptibility.Results The isolates were resolved into 20 STs.Two lineages were identified.MIC test showed that strains were more susceptible to aminoglycosides,The activity of quinolones and cephalosporin were higher than that of aminoglycosides.Conclusion MIST can determine homology of the strains from Pseudomonas aeruginosa keratitis by clustering results. There is no finding about relationship between Genetic typing and drug resistance.