Rat embryonic stem cells produce fertile offspring through tetraploid complementation.

Pluripotency of embryonic stem cells (ESCs) can be functionally assessed according to the developmental potency. Tetraploid complementation, through which an entire organism is produced from the pluripotent donor cells, is taken as the most stringent test for pluripotency. It remains unclear whether ESCs of other species besides mice can pass this test. Here we show that the rat ESCs derived under 2i (two small molecule inhibitors) conditions at very early passages are able to produce fertile offspring by tetraploid complementation. However, they lose this capacity rapidly during culture due to a nearly complete loss of genomic imprinting. Our findings support that the naïve ground state pluripotency can be captured in rat ESCs but also point to the species-specific differences in its regulation and maintenance, which have implications for the derivation and application of naïve pluripotent stem cells in other species including human.

Beijing Eye Public Health Care Project.

PURPOSE: The Beijing Eye Public Health Care Project was designed to screen all elderly subjects (age 55-85 years) of the rural region of Greater Beijing. It was developed as a preparatory step for a telemedicine-based public health care system in ophthalmology in China. DESIGN: Population-based public health care project. PARTICIPANTS: Elderly subjects (age 55-85 years) of the rural region of Greater Beijing. METHODS: Project participants were visited, interviewed, and examined by 2500 high school graduates trained as ophthalmic technicians. If visual acuity was <0.30, subjects were referred to primary health care centers where ocular photographs were taken. Using telemedicine, the photographs were transmitted to a reading center and causes for visual impairment were diagnosed. MAIN OUTCOME MEASURES: Practicability of a mass screening system in ophthalmology; prevalence of visual impairment and causes for it. RESULTS: Out of 692 323 eligible inhabitants, 562 788 (81.3%) subjects participated. Visual impairment in ≥1 eye was detected in 54 155 (9.62%) subjects, and among them, 30 164 (5.36%) subjects had bilateral visual impairment. Ocular fundus photographs were taken for 37 281 subjects. Cause for visual impairment was cataract in 19 163 (3.41%) of all screened subjects, glaucoma in 1606 (0.29%) subjects, diabetic retinopathy in 905 (0.16%) subjects, other macular diseases in 2700 (0.48%) subjects, pterygium in 1381 (0.25%) subjects, and corneal leukoma in 283 (0.05%) subjects. For 5853 (1.04%) subjects, a diagnosis of premature or mature cataract was made showing the urgent need of cataract surgery. After cataract surgery, visual acuity was ≥0.30 in 1464 (91.7%) of 1596 postoperatively reexamined subjects. CONCLUSIONS: Using a telemedicine approach, the Beijing Eye Public Health Care Project developed, applied and tested an infrastructure for ophthalmic mass screening of >500 000 elderly inhabitants with a response rate of >80%. Beside cataract, retinal diseases including diabetic retinopathy and glaucoma were major causes for visual impairment. FINANCIAL DISCLOSURE(S): The authors have no proprietary or commercial interest in any of the materials discussed in this article.

Epidemiology of pterygium in aged rural population of Beijing, China.

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Cataract and mortality. The Beijing eye study.

BACKGROUND: To assess an association between cataract and mortality in a population-based setting. METHODS: At baseline in 2001, the Beijing Eye Study examined 4255 subjects for cataract using standardized lens photographs which were examined according to the Age-Related Eye Disease Study scheme. In 2006, all study participants were re-invited for a follow-up examination. RESULTS: Out of the 4255 subjects, 3142 subjects (73.8%) returned for follow-up examination, while 135 subjects (3.2%) were dead and 978 subjects (23.0%) did not agree to be re-examined or had moved away. In multivariate analysis, the amount subcapsular cataract was significantly associated with increased mortality (P = 0.029; OR: 2.14; 95%CI: 1.08, 4.25), particularly for the subjects with an age of 65+ years and 70+ years (P = 0.016 and P = 0.003 respectively). Correspondingly, product of age times amount of subcapsular cataract was significantly associated with mortality (P = 0.001). Degree of nuclear cataract and amount of cortical cataract were not associated with mortality in multivariate analysis (P = 0.910 and P = 0.938 respectively). CONCLUSIONS: As also found in previous epidemiological studies on Western populations, cataract, namely subcapsular cataract in elderly subjects, is associated with an increased mortality risk.

A novel RPGR gene mutation in a Chinese family with X-linked dominant retinitis pigmentosa.

OBJECTIVE: To report a novel mutation in RPGR gene in a Chinese family with X-linked dominant retinitis pigmentosa(XLRP). METHODS: Genetic linkage analysis was performed on the known genetic loci for XLRP with a panel of polymorphic markers, then the mutations were identified by single-strand conformation polymorphism(SSCP) and direct sequencing. RESULTS: Significant two-point Lod score was generated using marker DXS8025 (Zmax=2.4, theta =0). The disease gene locus was confined to Xp21.1 with further analysis of genetic linkage and haplotype. Mutations screening of RPGR gene in this family revealed a GA deletion at ORF15+483-484 which caused the open reading frameshift. This novel mutation co-segregated with the affected members of the pedigree, but it was not present in the unaffected relatives. CONCLUSION: The above finding expands the spectrum of RPGR mutations causing XLRP in Chinese family and is useful for further genetic consultation and genetic diagnosis.

[Prevalence of low vision and blindness in defined populations in rural and urban areas in Beijing].

OBJECTIVE: To investigate the prevalence and causes of low vision and blindness in Beijing residents aged 40 and over. METHODS: 4,451 residents aged 40 and over in 3 rural communities and 5 urban communities in Beijing underwent eye examination, including examination of distant and near visual acuity (VA), best corrected distant and near VA, pinhole VA, and visual field, slit lamp biomicroscopy, and dilated ocular examination in the form of in-home survey by defined population-based sampling. The medical history was surveyed too. The data were analyzed based on the criteria of the World Health Organization. RESULTS: The general prevalence rates of low vision and blindness were 0.99% (95% CI: 0.70-1.28) and 0.39% (95% CI: 0.21-0.57) respectively. The prevalence rate of low vision in females was 1.45%, 2.23 times that of males (0.65%) (OR: 1.97, 95% CI: 1.00-3.95). The prevalence rate of low vision of rural residents was 1.76%, 2.89 times that of urban residents (0.61%) (OR: 2.93, 95% CI: 1.43-6.11). The prevalence rate of blindness in females was 0.64% and 0.37% in males. The prevalence rate of blindness of rural residents was 1.06%, 2.04 times that of the urban residents (0.52%) (OR: 3.77, 95% CI: 1.41-10.62). The 3 major causes of blindness were cataract (37.50%), glaucoma (29.20%), and high myopic macular degeneration (8.30%). The prevalence of blindness increased with age. CONCLUSION: The prevalence rates of low vision and blindness are higher in the rural areas. Cataract, glaucoma, and high myopic macular degeneration are the major causes of blindness. The prevalence of low vision and blindness are influenced by age, sex; area, health care level, educational level, and environmental factors.