Prior-guided attention fusion transformer for multi-lesion segmentation of diabetic retinopathy.

To solve the issue of diagnosis accuracy of diabetic retinopathy (DR) and reduce the workload of ophthalmologists, in this paper we propose a prior-guided attention fusion Transformer for multi-lesion segmentation of DR. An attention fusion module is proposed to improve the key generator to integrate self-attention and cross-attention and reduce the introduction of noise. The self-attention focuses on lesions themselves, capturing the correlation of lesions at a global scale, while the cross-attention, using pre-trained vessel masks as prior knowledge, utilizes the correlation between lesions and vessels to reduce the ambiguity of lesion detection caused by complex fundus structures. A shift block is introduced to expand association areas between lesions and vessels further and to enhance the sensitivity of the model to small-scale structures. To dynamically adjust the model's perception of features at different scales, we propose the scale-adaptive attention to adaptively learn fusion weights of feature maps at different scales in the decoder, capturing features and details more effectively. The experimental results on two public datasets (DDR and IDRiD) demonstrate that our model outperforms other state-of-the-art models for multi-lesion segmentation.

Bufadienolide-Fatty Acid Conjugates from the Fertilized Eggs of Toad Bufo gargarizans: Isolation, Characterization, Toxicity, and Antiproliferative Evaluation.

Bufadienolides (BDs) are a class of naturally occurring toxins present in amphibian toads. Serving as the chemical weapons, they exist not only in the adult toads but also in toad eggs. Guided by mass spectrometry (MS)-based component analysis and feature-based molecular networking (FBMN), 30 bufadienolide-fatty acid conjugates (BDFs) were isolated from the fertilized eggs of toad Bufo gargrizans, including 25 previously undescribed compounds (1-25). Their chemical structures were elucidated by extensive spectroscopic analysis, chemical methods, and GC-MS. The toxicities of all BDFs and their corresponding free BDs were assessed using the zebrafish model. The structure-toxicity relationship analysis showed that the modification of BDs by hydroxy fatty acids can cause a significant increase of the toxicity. Furthermore, all the isolated compounds were evaluated for their antiproliferative activities in pancreatic cancer cell lines ASPC-1 and PANC10.05. The structure-activity relationship (SAR) analysis revealed that BDFs with hellebrigenin as the bufogenin moiety (6 and 7) exhibited the most potent antiproliferative effect. Further investigation into their functional mechanism demonstrated that 6 and 7 induced apoptosis in pancreatic cancer cells PANC10.05 and significantly suppressed the expression of the apoptosis-related gene c-MYC. In addition, 6 and 7 effectively inhibited the expression of the PI3K/Akt/mTOR pathway in PANC10.05. Moreover, we assessed the efficacy of 6 and 7 on cancer cells from various tissues and observed their broad-spectrum antiproliferative activity.

Very long-chain fatty acids control peroxisome dynamics via a feedback loop in intestinal stem cells during gut regeneration.

Peroxisome dynamics are crucial for intestinal stem cell (ISC) differentiation and gut regeneration. However, the precise mechanisms that govern peroxisome dynamics within ISCs during gut regeneration remain unknown. Using mouse colitis and Drosophila intestine models, we have identified a negative-feedback control mechanism involving the transcription factors peroxisome proliferator-activated receptors (PPARs) and SOX21. This feedback mechanism effectively regulates peroxisome abundance during gut regeneration. Following gut injury, the released free very long-chain fatty acids (VLCFAs) increase peroxisome abundance by stimulating PPARs-PEX11s signaling. PPARs act to stimulate peroxisome fission and inhibit pexophagy. SOX21, which acts downstream of peroxisomes during ISC differentiation, induces peroxisome elimination through pexophagy while repressing PPAR expression. Hence, PPARs and SOX21 constitute a finely tuned negative-feedback loop that regulates peroxisome dynamics. These findings shed light on the complex molecular mechanisms underlying peroxisome regulation in ISCs, contributing to our understanding of gut renewal and repair.

How housing burden damages residents' health: evidence from Chinese cities.

Background: Currently, China is steadily pursuing high-quality development and promoting common prosperity, for which residents' health is a precondition. However, high housing-price-to-income ratios and rent-to-income ratios have already triggered many social problems and have substantially affected people's work and life. It is of practical significance to examine the relationship between housing burden and residents' health. Methods: Combining city-level housing price-to-income ratio data and residents' health data from the China Family Panel Studies, this study employs a binary logit model to investigate the impact and mechanism of housing burden on residents' physical and psychological health. Results: Overall, a 1% increase in the housing-price-to-income ratio leads to a 1.2% decrease in physical health and a 1.9% decrease in psychological health. In terms of different psychological state indicators, a 1% increase in the housing price-to-income ratio leads to a 1.1% increase in depression, 1.1% increase in nervousness, 1.4% increase in relentlessness, 1.4% increase in hopelessness, 1.0% increase in a sense of incapability, and 1.4% increase in meaninglessness. According to mechanistic analyses, a 1% increase in the housing-price-to-income ratio leads to increases of 0.6 and 0.7% in the smoking rate and late sleep rate, respectively, while it leads to a 0.9% decrease in the noon nap rate. Conclusion: A growing housing burden significantly negatively impacts both the physical and psychological health of residents and increases the possibility of negative emotions. Further investigation revealed that the housing burden damages residents' health by increasing their likelihood of smoking and sleeping late and decreasing their likelihood of taking a nap at noon, while exercise alleviates the negative impacts of the housing burden on residents' physical and psychological health. Finally, we also find that housing burdens' impacts on physical and psychological health differ significantly in terms of gender, age, and educational attainment. From the perspective of improving livelihoods, governments should consider the relationship between housing burdens and residents' health when formulating livelihood policies. Location-specific and targeted policies should be followed. Additionally, efforts should be made to promote exercise among citizens.

A novel multi-task learning network for skin lesion classification based on multi-modal clues and label-level fusion.

In this paper, we propose a multi-task learning (MTL) network based on the label-level fusion of metadata and hand-crafted features by unsupervised clustering to generate new clustering labels as an optimization goal. We propose a MTL module (MTLM) that incorporates an attention mechanism to enable the model to learn more integrated, variable information. We propose a dynamic strategy to adjust the loss weights of different tasks, and trade off the contributions of multiple branches. Instead of feature-level fusion, we propose label-level fusion and combine the results of our proposed MTLM with the results of the image classification network to achieve better lesion prediction on multiple dermatological datasets. We verify the effectiveness of the proposed model by quantitative and qualitative measures. The MTL network using multi-modal clues and label-level fusion can yield the significant performance improvement for skin lesion classification.

The associations of self-perception, movement competence, and clinical features of young school-aged children with glaucoma.

The purpose of the study was to determine the associations of self-perception, motor skills, and clinical features of young school-age children with glaucoma (CG). This is a cross-sectional observational study. Children from preschool to second grade, including CG (N = 19), children with amblyopia (CA, N = 28), and controls (N = 32), completed the Manual Dexterity and Aiming and Catching Scales of the Movement Assessment Battery for Children-2nd edition (MABC-2), including Manual Dexterity, Aiming and Catching, and Balance. CG, CA, and their parent completed the Pictorial Scale of Perceived Competence and Social Acceptance for Young Children, respectively, assessing the child's cognitive competence, peer acceptance, physical competence, and maternal acceptance. The Kruskal-Wallis H test and Bonferroni post hoc test compared motor skills among groups. Spearman's correlation analysis evaluated the correlations between motor skills, self-perception, and clinical features. The CG reported lower peer acceptance than CA (P = 0.040), and the parents of CG reported lower cognitive competence than CG reported (P = 0.046). Compared with controls, CG had worse performance of Aiming and Catching, and Balance (P = 0.018 and P = 0.001), and CA had worse performance of Balance (P = 0.009). The motor skills were comparable between CG and CA. For CG, older age correlated with worse competence of Aiming and Catching (r = - 0.620, P = 0.005), better best-corrected visual acuity of better-seeing eye correlated with higher competence of Manual Dexterity and Balance (r = - 0.494, P = 0.032, and r = - 0.516, P = 0.024), and longer duration of glaucoma correlated with worse competence of Manual Dexterity (r = - 0.487, P = 0.034). CONCLUSION:  Glaucoma and amblyopia have significant negative impacts on children's daily motor skills. The acuity of a better-seeing eye is an important factor influencing motor movement. TRIAL REGISTRATION: ClinicalTrials.gov identifier, ChiCTR2100050415. WHAT IS KNOWN: • The state of mental health in early childhood influences the development of their future personality and physical development. The prognosis and management of glaucoma may seriously impair the mental health development of the affected children. However, the exploration of psychological aspects and motor movement of childhood glaucoma was limited. WHAT IS NEW: • Children with glaucoma have impaired motor skills and self-perception development, especially in terms of peer socialization.

Population agglomeration in Chinese cities: is it benefit or damage for the quality of economic development?

This paper explores the impact of population agglomeration on urban economic development quality in various cities of China. The results show that population agglomeration significantly contributes to the improvement of urban green total factor productivity by increasing population diversification, promoting knowledge spillovers, and reducing pollution emission intensity. Moreover, we find that population agglomeration in type II big cities and type I large cities significantly improves green total factor productivity, while the impact of population agglomeration in metropolises and mega-cities on green total factor productivity is not significant. On the one hand, type II big cities and type I large cities are in the period of rising economic development, the population has not yet reached saturation, and there is still a large demographic dividend space. On the other hand, excessive population agglomeration also brings about "urban diseases" such as population congestion and traffic congestion, especially in the metropolises and mega-cities. Finally, using data on producer services and its sub-sectors, we identify a more significant driving effect of high-end talent agglomeration on green total factor productivity.

Sleep loss impairs intestinal stem cell function and gut homeostasis through the modulation of the GABA signalling pathway in Drosophila.

Sleep is essential for maintaining health. Indeed, sleep loss is closely associated with multiple health problems, including gastrointestinal disorders. However, it is not yet clear whether sleep loss affects the function of intestinal stem cells (ISCs). Mechanical sleep deprivation and sss mutant flies were used to generate the sleep loss model. qRT-PCR was used to measure the relative mRNA expression. Gene knock-in flies were used to observe protein localization and expression patterns. Immunofluorescence staining was used to determine the intestinal phenotype. The shift in gut microbiota was observed using 16S rRNA sequencing and analysis. Sleep loss caused by mechanical sleep deprivation and sss mutants disturbs ISC proliferation and intestinal epithelial repair through the brain-gut axis. In addition, disruption of SSS causes gut microbiota dysbiosis in Drosophila. As regards the mechanism, gut microbiota and the GABA signalling pathway both partially played a role in the sss regulation of ISC proliferation and gut function. The research shows that sleep loss disturbed ISC proliferation, gut microbiota, and gut function. Therefore, our results offer a stem cell perspective on brain-gut communication, with details on the effect of the environment on ISCs.

Facile construction of Z-scheme AgCl/Bi3TaO7 photocatalysts for effective removal of tetracycline under visible-light irradiation.

A string of AgCl/Bi3TaO7 two-component composite was synthesized by hydrothermal and deposition-precipitation process initially. The photocatalytic activities of mixed-phase AgCl/Bi3TaO7 were evaluated toward the decomposition of tetracycline (TC). Among these as-prepared materials, AgCl/Bi3TaO7 nanocomposites when the molar ratio of baked materials between AgCl and Bi3TaO7 was 1:5 presented the optimal photocatalytic quantum efficiency for TC dissociation (86.82%) with visible-light exposure, which was 1.69 and 2.38 folders higher than that of single Bi3TaO7 and AgCl, respectively. What is more, it illustrated that the photo-generated carriers were markedly isolated on account of the formation of heterojunction confirmed by EIS analysis. Meanwhile, radical trapping experiments implied that the photo-induced holes (h+), hydroxyl radical (·OH), and superoxide radical (·O2-) were the major active species. The escalated photocatalytic activity could be ascribed to the unique construction of Z-scheme AgCl/Bi3TaO7 heterojunction, which could expedite charge separation and transmission, cement light absorption capability and retain the strong redox ability of photo-generated electrons and holes. Our finding suggests that AgCl/Bi3TaO7 nanocomposites possess great potential for photocatalytic oxidation of residual TC in the wastewater effluents and the reported strategy can contribute to the development of novel high-performance photocatalyst.

The impact of lockdown in Wuhan on residents confidence in controlling COVID-19 outbreak at the destination cities.

Objective: From January 23rd, 2020, lock-down measures were adopted in Wuhan, China to stop the spread of COVID-19. However, due to the approach of the Spring Festival and the nature of COVID-19, more than 6 million permanent and temporary residents of Wuhan (who were potential carriers or spreaders of the virus), left the city before the lock-down measures were implemented. This study aims to explore whether and how the population inflow from Wuhan city impacted residents' confidence in controlling COVID-19 outbreaks at the destination cities. Study design and setting: Based on questionnaire data and migration big data, a multiple regression model was developed to quantify the impact of the population inflow from Wuhan city on the sense of confidence of residents in controlling the COVID-19 outbreak at the destination cities. Scenarios were considered that varied residents' expected month for controlling COVID-19 outbreak at the destination cities, residents' confidence in controlling COVID-19 outbreak at the destination cities, and the overall indicators for the sense of confidence of residents in controlling COVID-19. A marginal effect analysis was also conducted to calculate the probability of change in residents' confidence in controlling the COVID-19 outbreak with per unit change in the population inflow from Wuhan city. Results: The impact of population inflow from Wuhan city on residents' expected month for controlling COVID-19 outbreak at the destination cities was positive and significant at the 1% level, while that on residents' confidence in controlling COVID-19 at the destination cities was negative and significant at the 1% level. Robustness checks, which included modifying the sample range and replacing measurement indicators of the population inflow from Wuhan city, demonstrated these findings were robust and credible. When the population inflow from Wuhan city increased by one additional unit, the probabilities of the variables "February" and "March" decreased significantly by 0.1023 and 0.1602, respectively, while the probabilities of "April," "May," "June," "July," "before the end of 2020," and "unknown" significantly increased by 0.0470, 0.0856, 0.0333, 0.0080, 0.0046, and 0.0840, respectively. Similarly, when the population inflow from Wuhan city increased by one additional unit, the probability of the variable "extremely confident" decreased by 0.1973. Furthermore, the probabilities of the variables "confident," "neutral," and "unconfident" significantly increased by 0.1392, 0.0224, and 0.0320, respectively. Conclusion: The population inflow from Wuhan city played a negative role in the sense of confidence of residents in controlling COVID-19 in the destination cities. The higher the population inflow from Wuhan city, the longer the residents' expected month for controlling COVID-19 outbreak at the destination cities became, and the weaker the residents' confidence in controlling the COVID-19 outbreak at the destination cities.

Tunable Toxicity of Bufadienolides is Regulated through a Configuration Inversion Catalyzed by a Short-Chain Dehydrogenase/Reductase.

Bufadienolides are toxic components widely found in amphibious toads that exhibit a wide range of biological activities. Guided by UPLC-QTOF-MS analysis, several 3-epi-bufadienolides with unique structures were isolated from the bile of the Asiatic toad, Bufo gargarizans. However, the enzymatic machinery of this epimerization in toads and its significance in chemical ecology remains poorly understood. Herein, we firstly compared the toxicities of two typical bufadienolides, bufalin (featuring a 14ß-hydroxyl) and resibufogenin (containing a 14, 15-epoxy group), with their corresponding 3-epi isomers in a zebrafish model. The results of the toxicology assays showed that the ratio of maximum non-toxic concentrations of these two pairs of compounds are 256 and 96 times, respectively, thereby indicating that 3-hydroxyl epimerization leads to a significant decrease in toxicity. Aiming to investigate the biotransformation of 3-epi bufadienolides in toads, we applied liver lysate to transform bufalin and found that it could stereoselectively catalyze the conversion of bufalin into its 3α-hydroxyl epimer. Following this, we cloned and characterized a short-chain dehydrogenase/reductase, HSE-1, from the toad liver cDNA library and verified its 3(ß→α)-hydroxysteroid epimerization activity. To the best of our knowledge, this is the first hydroxyl epimerase identified from amphibians that regulates the toxicity of animal-derived natural products.

Joint optic disc and cup segmentation using feature fusion and attention.

Currently, glaucoma is one of the leading causes of irreversible vision loss. So far, glaucoma is incurable, but early treatment can stop the progression of the condition and slow down the speed and extent of vision loss. Early detection and treatment are crucial to prevent glaucoma from developing into blindness. It is an effective method for glaucoma diagnosis to measure Cup to Disc Ratio (CDR) by the segmentation of Optic Disc (OD) and Optic Cup (OC). Compared with OD segmentation, OC segmentation still faces difficulties in segmentation accuracy. In this paper, a deep learning architecture named FAU-Net (feature fusion and attention U-Net) is proposed for the joint segmentation of OD and OC. It is an improved architecture based on U-Net. By adding a feature fusion module in U-Net, information loss in feature extraction can be reduced. The channel and spatial attention mechanisms are combined to highlight the important features related to the segmentation task and suppress the expression of irrelevant regional features. Finally, a multi-label loss is used to generate the final joint segmentation of OD and OC. Experimental results show that the proposed FAU-Net outperforms the state-of-the-art segmentation of OD and OC on Drishti-GS1, REFUGE, RIM-ONE and ODIR datasets.

Evidence of an Annexin A4 mediated plasma membrane repair response to biomechanical strain associated with glaucoma pathogenesis.

Glaucoma is a common neurodegenerative blinding disease that is closely associated with chronic biomechanical strain at the optic nerve head (ONH). Yet, the cellular injury and mechanosensing mechanisms underlying the resulting damage have remained critically unclear. We previously identified Annexin A4 (ANXA4) from a proteomic analyses of human ONH astrocytes undergoing pathological biomechanical strain that mimics glaucomatous conditions. Annexins are a family of calcium-dependent phospholipid binding proteins with key functions in plasma membrane repair (PMR); an active mechanism to limit and mend cellular injury that involves membrane and cytoskeletal reorganizations. However, a role for direct membrane damage and PMR has not been well studied in the context of biomechanical strain, such as that associated with glaucoma. Here we report that this moderate strain surprisingly damages cell membranes to increase permeability in a calcium-dependent manner, and induces rapid aggregation of ANXA4 at injury sites. ANXA4 loss-of-function increases permeability, while exogenous ANXA4 reduces it. Furthermore, ANXA4 aggregation is associated with F-actin dynamics in vitro, and remarkably this interaction and aggregation signature is also observed in the glaucomatous ONH in patient samples. Together these studies link moderate biomechanical strain with direct membrane damage and actin dynamics, and identify an active PMR role for ANXA4 in new model of cell injury associated with glaucoma pathogenesis.

A Novel U-Net Based Deep Learning Method for 3D Cardiovascular MRI Segmentation.

Medical multiobjective image segmentation aims to group pixels to form multiple regions based on the different properties of the medical images. Segmenting the 3D cardiovascular magnetic resonance (CMR) images is still a challenging task owing to several reasons, including individual differences in heart shapes, varying signal intensities, and differences in data signal-to-noise ratios. This paper proposes a novel and efficient U-Net-based 3D sparse convolutional network named SparseVoxNet. In this network, there are direct connections between any two layers with the same feature-map size, and the number of connections is reduced. Therefore, the SparseVoxNet can effectively cope with the optimization problem of gradients vanishing when training a 3D deep neural network model on small sample data by significantly decreasing the network depth, and achieveing better feature representation using a spatial self-attention mechanism finally. The proposed method in this paper has been thoroughly evaluated on the HVSMR 2016 dataset. Compared with other methods, the method achieves better performance.

AUTOMATIC DETECTION AND GRADING OF DIABETIC MACULAR EDEMA BASED ON A DEEP NEURAL NETWORK.

PURPOSE: To solve the problem of automatic grading of macular edema in retinal images in a more stable and reliable way and reduce the workload of ophthalmologists, an automatic detection and grading method of diabetic macular edema based on a deep neural network is proposed. METHODS: The enhanced green channels of fundus images are input into the YOLO network for training and testing. Diabetic macular edema is graded according to the distance of the macula and hard exudate. We used multiscale feature fusion to form more comprehensive features on different grain images to improve the effect of hard exudate detection. We adopted K-means++ algorithm to cluster anchor box size and use loss of the original network to guide the regression of hard exudate bounding box and improve the regression accuracy of anchor boxes. We increased the diversity of samples for sample training by data augmentation, including cropping, flipping, and rotating of fundus images, so that each batch of training data can better represent the distribution of samples. RESULTS: The detection accuracy of the proposed method can reach 96% on the MESSIDOR data set. The detection rates of hard exudate with high, median, and low probability are 100%, 79.12%, and 60.40%, respectively. CONCLUSION: The proposed method exhibits a very good detection stability on healthy and diseased fundus images.

Quercetin Prevents Intestinal Stem Cell Aging via Scavenging ROS and Inhibiting Insulin Signaling in Drosophila.

Adult stem cells, a class of cells that possess self-renewal and differentiation capabilities, modulate tissue regeneration, repair, and homeostasis maintenance. These cells undergo functional degeneration during aging, resulting in decreased tissue regeneration ability and increased disease incidence. Thus, it is essential to provide effective therapeutic solutions to preventing the aging-related functional decline of stem cells. Quercetin (Que) is a popular natural polyphenolic flavonoid found in various plant species. It exhibits many beneficial effects against aging and aging-related diseases; however, its efficacy against adult stem cell aging remains largely unclear. Drosophila possesses a mammalian-like intestinal system with a well-studied intestinal stem cell (ISC) lineage, making it an attractive model for adult stem cell research. Here, we show that Que supplementation could effectively prevent the hyperproliferation of ISCs, maintain intestinal homeostasis, and prolong the lifespan in aged Drosophila. In addition, we found that Que could accelerate recovery of the damaged gut and improve the tolerance of Drosophila to stressful stimuli. Furthermore, results demonstrated that Que prevents the age-associated functional decline of ISCs via scavenging reactive oxygen species (ROS) and inhibiting the insulin signaling pathway. Overall, our findings suggest that Que plays a significant role in delaying adult stem cell aging.

Quantitative proteomics reveals differential immunoglobulin-associated proteome (IgAP) in patients of acute myocardial infarction and chronic coronary syndromes.

B cells and immunoglobulins are implicated in the pathogenesis of chronic diseases, including coronary artery disease (CAD). However, it remains elusive how the humoral immunity is incriminated in the disease progression of CAD. Using serum samples of chronic coronary syndrome (CCS) and acute myocardial infarction (AMI), we conducted a quantitative profiling of the proteomic landscape recognized by immunoglobulins, which we term immunoglobulin-associated proteome (IgAP). Intriguingly, CCS and AMI patients displayed distinctive IgAP profiles that enriched proteins in the pathways of blood coagulation regulation and lipoprotein transport, suggesting that CCS-AMI transition involves changes of these pathways that are associated with immunoglobulins. Furthermore, we identified immunoglobulin-bound coagulation factor X (F10) as a potential biomarker and validated it with an independent cohort of CCS, AMI and healthy individuals. Our study indicates that IgAP proteins may serve as novel diagnostic biomarkers for CCS and AMI. SIGNIFICANCE: Our work it demonstrates a clear implication of immunoglobulin-associated proteome (IgAP), the proteomic landscape recognized by immunoglobulins, in the pathogenesis of CAD. In addition, it reports for the first time that immunoglobulin-bound F10 is implicated in CAD.

What determines city's resilience against epidemic outbreak: evidence from China's COVID-19 experience.

By employing the city-level data from China during the spring of 2020, this study investigates the relationship between city-level resilience against the outbreak of COVID-19 pandemics and its affecting factors, including the inflow risk pressure of COVID-19 virus (population inflow from the epicenter), city agglomeration characteristics (urban population density and city size), healthcare resource adequacy, among others. The results reveal that, while managing COVID-19 inflow risk pressure plays a critical role in the city's pandemic disaster resilience, city agglomeration characteristics also matters. To be exact, we find that large and high-density cities with high inter and intra-city mobility flows have more difficulties in containing the epidemic spread, but improving healthcare infrastructure adequacy and urban governance capacity can increase time efficacy of pandemic control and then improve the city's resilience against pandemic. Although our analysis is based on the performance of Chinese cities in the case of COVID-19, the research framework can be applied in understanding COVID-19 control performance of cities in other countries and the findings can be useful for improving health-related urban resilience and sustainability.

Robust Fovea Localization Based on Symmetry Measure.

Automatic fovea localization is a challenging issue. In this article, we focus on the study of fovea localization and propose a robust fovea localization method. We propose concentric circular sectional symmetry measure (CCSSM) for symmetry axis detection, and region of interest (ROI) determination, which is a global feature descriptor robust against local feature changes, to solve the lesion interference issue, i.e., fovea visibility interference from lesions, using both structure features and morphological features. We propose the index of convexity and concavity (ICC) as the convexity-concavity measure of the surface and provide a quantitative evaluation tool for ophthalmologists to learn whether the occurrence of lesion within the ROI. We propose the weighted gradient accumulation map, which is insensitive to local intensity changes and can overcome the influence of noise and contamination, to perform refined localization. The advantages of the proposed method lies in two aspects. First, the accuracy and robustness can be achieved without typical sophisticated manner, i.e., blood vessel segmentation and parabola fitting. Second, the lesion interference is considered in our plan of fovea localization. Our proposed symmetry-based method is innovative in the solution of fovea detection, and it is simple, practical, and controllable. Experiment results show that the proposed method can resist the interference of unbalanced illumination and lesions, and achieve high accuracy rate in five datasets. Compared to the state-of-the-art methods, high robustness and accuracy of the proposed method guarantees its reliability.

Identification of CRB1 mutations in two Chinese consanguineous families exhibiting autosomal recessive retinitis pigmentosa.

Retinitis pigmentosa (RP) is a leading cause of inherited blindness characterized by progressive loss of retinal photoreceptor cells. The present study aimed to identify the causative gene mutations in two Chinese families with autosomal recessive retinitis pigmentosa (arRP). Two Chinese consanguineous arRP families (RP­2284 and RP­2360) were recruited in this study, involving totally three affected and 25 unaffected members. All the affected members underwent a complete ophthalmic examination, including fundus photography, multifocal electroretinography (ERG) and full field ERG. Exome sequencing was performed on the three RP patients in the two families, followed by direct Sanger sequencing in all the family members and in 1,260 unrelated controls for validation of the mutations identified. Two homozygous missense mutations in the crumbs homolog 1 (CRB1) gene, which is known to cause severe retinal dystrophies, were found to be related to the phenotype of the two arRP families. The homozygous missense mutation c.1997 T>A in CRB1 was detected in two patients in the RP­2284 family. The proband in the RP­2360 family was the only RP patient and was found to carry the novel homozygous missense mutation c.2426 A>C in CRB1. The two mutations were heterozygous or absent in the other healthy family members, and they were absent in the 1,260 controls. The amino acid changes in the CRB1 protein affected by the two mutations were predicted to be damaging by Polyohen­2. Our study reported two CRB1 mutations causing arRP in two Chinese families, which expands the CRB1 mutation spectrum of RP in the Chinese population and emphasizes the causative role of CRB1 in RP.