[Chromosomal microarray analysis of 17 patients with unbalanced reciprocal translocations].

OBJECTIVE: To retrospectively analyze the results of chromosomal microarray analysis (CMA) and parental origins of unbalanced translocations among 17 patients, so as to provide reference for their genetic counseling. METHODS: The results of CMA for 7 001 samples tested in Chengdu Women and Children's Central Hospital from January 2019 to January 2022 were retrospectively reviewed. Unbalanced reciprocal translocation was defined as two non-homologous chromosomes with lost and gained segments respectively or both with gained segments, and their parental origins were identified by parental chromosomal karyotyping and/or fluorescence in situ hybridization (FISH). RESULTS: In total 17 unbalanced translocations were identified. In three cases, two non-homologous chromosomes both had gained segments, which constituted a derivative chromosome, with the total number of chromosomes being 47. In the remaining 14 cases, there was a terminal deletion on one chromosome and a terminal duplication on the other, 10 of which were confirmed by karyotyping, with the total number of chromosomes being 46. In the derivative chromosome, the lost segment was replaced by a gained segment from another chromosome. Among 15 cases undergoing parental origin analysis, 12 had paternal or maternal chromosomal abnormalities, including 11 balanced translocations and 1 unbalanced translocation. The unbalanced gametes therefore may form through meiosis. In 3 cases, the parental chromosomes were normal, indicating a de novo origin. CONCLUSION: Discovery of terminal duplication and deletion or gained segments on two non-homologous chromosomes by CMA is suggestive of parental balanced translocation, which can facilitate genetic counseling and assessment the recurrence risk for subsequent pregnancies.

Image processing strategies based on saliency segmentation for object recognition under simulated prosthetic vision.

BACKGROUND AND OBJECTIVE: Current retinal prostheses can only generate low-resolution visual percepts constituted of limited phosphenes which are elicited by an electrode array and with uncontrollable color and restricted grayscale. Under this visual perception, prosthetic recipients can just complete some simple visual tasks, but more complex tasks like face identification/object recognition are extremely difficult. Therefore, it is necessary to investigate and apply image processing strategies for optimizing the visual perception of the recipients. This study focuses on recognition of the object of interest employing simulated prosthetic vision. METHOD: We used a saliency segmentation method based on a biologically plausible graph-based visual saliency model and a grabCut-based self-adaptive-iterative optimization framework to automatically extract foreground objects. Based on this, two image processing strategies, Addition of Separate Pixelization and Background Pixel Shrink, were further utilized to enhance the extracted foreground objects. RESULTS: i) The results showed by verification of psychophysical experiments that under simulated prosthetic vision, both strategies had marked advantages over Direct Pixelization in terms of recognition accuracy and efficiency. ii) We also found that recognition performance under two strategies was tied to the segmentation results and was affected positively by the paired-interrelated objects in the scene. CONCLUSION: The use of the saliency segmentation method and image processing strategies can automatically extract and enhance foreground objects, and significantly improve object recognition performance towards recipients implanted a high-density implant.

High-accuracy simultaneous measurement of particle size and location using interferometric out-of-focus imaging.

A method based on unidirectional gradient-matched algorithm and Fourier transform technique is proposed to simultaneously extract the location and the number of fringes/fringe spacing of a particle interferogram. The position coordinate (x,y) of a particle can be determined with high accuracy because of the elimination of the fringe within the particle fringe pattern. Furthermore, the method can be employed to achieve sub-pixel frequency extraction when combined with an improved Rife algorithm. The performance of the method has been verified by numerical simulations and experimental measurements. The results suggest that the method presented here is highly beneficial to applications such as spray, in accurately measuring both the particle size and its location.

Face recognition in simulated prosthetic vision: face detection-based image processing strategies.

OBJECTIVE: Given the limited visual percepts elicited by current prosthetic devices, it is essential to optimize image content in order to assist implant wearers to achieve better performance of visual tasks. This study focuses on recognition of familiar faces using simulated prosthetic vision. APPROACH: Combined with region-of-interest (ROI) magnification, three face extraction strategies based on a face detection technique were used: the Viola-Jones face region, the statistical face region (SFR) and the matting face region. MAIN RESULTS: These strategies significantly enhanced recognition performance compared to directly lowering resolution (DLR) with Gaussian dots. The inclusion of certain external features, such as hairstyle, was beneficial for face recognition. Given the high recognition accuracy achieved and applicable processing speed, SFR-ROI was the preferred strategy. DLR processing resulted in significant face gender recognition differences (i.e. females were more easily recognized than males), but these differences were not apparent with other strategies. SIGNIFICANCE: Face detection-based image processing strategies improved visual perception by highlighting useful information. Their use is advisable for face recognition when using low-resolution prosthetic vision. These results provide information for the continued design of image processing modules for use in visual prosthetics, thus maximizing the benefits for future prosthesis wearers.

Optimizing Chinese character displays improves recognition and reading performance of simulated irregular phosphene maps.

PURPOSE: A visual prosthesis may elicit an irregular phosphene map relative to a regular electrode array. This study used simulated irregular phosphene maps as a way of optimizing the display methods of Chinese characters (CCs) to improve recognition and reading performance. METHODS: TWENTY SUBJECTS WITH NORMAL OR CORRECTED SIGHT PARTICIPATED IN TWO EXPERIMENTS (9 FEMALES, 11 MALES, 2030 YEARS OF AGE). EXPERIMENT 1: two character display methods were proposed: selecting phosphenes covered by character strokes on a simulated phosphene array (projection method) and finding the phosphene closest to the expected location in some range of an irregular phosphene array as a substitute (nearest neighbor search [NNS] method). The recognition accuracy of CCs was investigated using six levels for the coverage ratio of stroke and phosphene area and for search range, respectively, for two methods, for several irregularity levels. Experiment 2: reading accuracy (RA) and reading efficiency (RE) were measured using the regular array correspondence and NNS methods. RESULTS: EXPERIMENT 1: projection and NNS methods were significantly affected by coverage ratio or search range. NNS significantly improved CC recognition accuracy to the highest at 81.3 ± 2.7% and 59.1 ± 5.2%, respectively, for different irregularity levels, compared with the projection method. Experiment 2: RA and RE significantly decreased as the distortion level increased; NNS significantly improved RA (from approximately 40% to >80%) and RE (from approximately 13 char/min to >40 char/min) when reading more irregular paragraphs. CONCLUSIONS: The performance of CC recognition and paragraph reading when using an irregular phosphene array can be improved through optimizing the display method.

Protective effects of the aqueous extract of Scutellaria baicalensis against acrolein-induced oxidative stress in cultured human umbilical vein endothelial cells.

CONTEXT: Scutellaria baicalensis Georgi (Labiatae) (SbG), one of the fifty fundamental herbs of Chinese herbology, has been reported to have anti-asthmatic, antifungal, antioxidative, and anti-inflammatory activities. OBJECTIVE: This study was designed to determine the protective effects of the extract of SbG against the acrolein-induced oxidative stress in cultured human umbilical vein endothelial cells (HUVEC). MATERIALS AND METHODS: The MTT reduction assay was employed to determine cell viability. The total cellular glutathione (GSH) level was detected using a colorimetric GSH assay kit. Cellular GSH production was conducted by detecting the mRNA expression levels of γ-glutamylcysteine ligase catalytic subunit and modifier subunit. RESULTS: Concentration-dependent cytotoxic effects of acrolein were observed while SbG could effectively protect the acrolein-induced oxidative damage. The protective mechanism was investigated, showing that the increased GSH content in the SbG-incubated HUVE cells was associated with the protective effects of SbG-treated cells. Further RT-PCR data confirmed the elevated mRNA expressions of GSH synthesis enzymes. DISCUSSION AND CONCLUSION: The current study strongly indicated that SbG could be a potential antioxidant against oxidative stress in treating cardiovascular diseases.