Objective Present study aimed to research the mechanism of the use of 0.2% brimonidine tartrate eye drops in the treatment of optic nerve crush injury of rat.MethodsAnimal models of optic nerve crush injury were created in 60 SD female rats by clipping the exposed optic nerve at 2 mm in retrobulbar for 6 seconds with 78 grams of reverse forceps.The successful model was identified as Marcus-gun pupil without bleeding of fundus after operation.The animals were randomly assigned to model group and brimonidine treating group,and another 30 normal SD rats were used as the normal control group.The 0.2% brimonidine tartrate eye drops was topically administered at 2 hours before operation and after operation twice per day in the brimonidine treating group.The retinas from 18 rats were isolated after 3,7,21 days for RGCs counting by H&E staining,and the retinal ultrastructure was examined under the transmission electron microscope.The retinas from the other 72 SD rats (including normal,model and brimonidine groups) were prepared for the detection of bcl-2 and bax using immunohistochemistry l,3,5,7,14,21 days after the operation.ResultsNormal and almost normal retina structure was exhibited in rats of the normal group and brimonidine treating group,but disorder of cellular arragement and decrease of retinal thickness were found in the model rats under the optical microscope.The RGCs counting was significantly different among the three groups from 3 days through 21 days after operation with the considerably declination in the model group and brimonidine treating group compared with the normal control group (P＜0.05-0.01).However,that of the brimonidine treating group was obviously increased in comparison with the model group (P＜0.01).The expression of bax in rat retina was obviously reduced (P＜0.01),but the expression of bcl-2 was increased in brimonidine group compared with the model group from 5 through 7 days after operation (P＜0.01).ConclusionThe 0.2% brimonidine tartrate eye drops has a preventive effect on optic nerve crush injury of rat,and its inhibition on apoptosis is one of the mechanisms.

Objectives Tostudytheexpressionchangesofproproteinconvertase1(PC1)incerebral cortex nerve cells and its substrate neuropeptide Y (NPY)after focal cerebral ischemia in mice and to investigatetheeffectofPC1inneuronalischemicinjury.Methods Twenty-fourmaleC57micewere randomly allocated into a sham-operation group,an ischemia-reperfusion 4-or 24-hour group with computer (n=8 in each group). A rat model of middle cerebral artery occlusion was induced by the intraluminal suture method. Western blot and real-time quantitative nucleic acid amplification were used to detect the expression changes of PC1,NPY,and mRNA in mouse cortical neurons. Results (1)Compared with the sham operation group,the expression of PC1 mRNA of ischemic cortex brain tissue at ischemic side in the ischemia-reperfusion 4-hour group increased 2. 66 ± 0. 24 and in the ischemia-reperfusion 24-hour group expressed 2. 07 ± 0. 23 (all P<0. 05). Compared with the sham operation group,the PC1 precursor protein level increased significantly at 4 hours (P<0. 05). There was no significant difference in the 24-hour group (P >0. 05 ). (2 )Compared with the sham operation group,the preproNPY mRNA and protein level increased significantly after reperfusion in the ischemia-reperfusion 4-hour group (P < 0. 05 ),the mRNA expressed 2. 31 ± 0. 27,and the increase of precursor protein level continued until 24 hours. Conclusion TheexpressionofprecursorPC1increasedaftercerebralischemia-reperfusioninmice, thus affecting the processing activity of PC1 ,and resulting in NPY protein,an active substrate of PC1 accumulated with the form of precursors,which may be one of the underlying mechanisms of neuronal ischemic injury.

Objective: To explore the role of MRI in the pre-operative diagnosis and classification of oblique vaginal septum syndrome (OVSS) . Methods: A retrospective analysis of the clinical records and pre-operative MRI images of 19 patients with surgery proved OVSS was carried out. Two experienced radiologists reviewed the pre-operative pelvic MRI of the 19 patients in consensus blind to the surgery results. Characteristics including malformations of the uterus, cervix and vagina, the diagnosis of the disorder and classification were evaluated. Pre-operative MRI diagnosis and classification were correlated with surgical findings. Results: Mean age of onset of symptoms for the 19 patients was 15 years (ranged 9-25 years) , and mean age of menarche was 12 years. Ten patients suffered from dysmenorrhea or lower abdominal pain, 5 patients complained of vaginal discharge, 3 patients had a history of irregular menstruation, 1 patient suffered from primary infertility. All 19 patients showed uteri didelphys. Eighteen patients showed vaginal oblique septum.One patient showed cervical atresia.MRI was completely correlated with the surgery in the pre-operative diagnosis of OVSS. MRI classification was in line with surgery in 17 patients, including 9 patients with imperforate septum (typeⅠ) , 6 patients with perforate septum (type Ⅱ) , 1 patient with imperforate septum and cervical fistula (type Ⅲ) , and another one with cervical agenesis (type Ⅳ) . One case of type Ⅱ was misdiagnosed as type Ⅰ, another one of type Ⅰ was misdiagnosed as type Ⅲ. Pre-operative MRI classification was correlated with surgery in 17 out of 19 patients. Conclusion Pre-operative MRI allows excellent manifestation and accurate diagnosis of OVSS, and could also facilitate the evaluation of the classification.

Objective:To explore the feasibility in evaluating segmental extracellular volume (ECV) using dual-layer spectral detector CT in patients with heart failure with various percentages of delayed hyper-enhanced volume, using MRI as a reference.Methods:Twenty-seven patients with heart failure in Peking Union Medical College Hospital were prospectively enrolled in this study from July 2019 to January 2021. All the patients underwent both CT late iodine enhancement and MR late gadolinium enhancement imaging within a week. According to percentages of hyper-enhanced volume on cardiac MR image, myocardial segments were classified into 3 groups: 0-4% (group A), 5%-49% (group B) and 50%-100% (group C). ECV images were independently observed by 2 experienced radiologists. The correlation and agreement between CT-ECV and MRI-ECV for the whole myocardial assessment and for the segmental assessment were evaluated using Spearman correlation and Bland-Altman analysis. Inter-observer agreement was assessed using the ICC.Results:Of the 27 patients, 432 segments were analyzed, with 199 segments in group A, 151 segments in group B and 82 segments in group C. In the whole myocardial analysis, the CT-ECV and MRI-ECV were 32.25% (28.04%, 34.28%) and 32.27% (28.35%, 34.77%), respectively. A good correlation was found between CT-ECV and MRI-ECV ( r=0.969, P<0.001). Bland-Altman analysis between CT-ECV and MRI-ECV showed a small bias (0.4%), with 95% limits of agreement of -6.9% to 7.8%. as for the segmental myocardial assessment, the CT-ECV was 28.23% (26.18%, 29.92%) for group A, 33.29% (30.16%, 35.96%) for group B and 40.22% (34.06%, 46.70%) for group C. There was statistically significant difference in ECV among three groups (all P<0.001). Good correlations between CT-ECV and MRI-ECV were found in group A ( r=0.614, P<0.001), group B ( r=0.852, P<0.001) and group C ( r=0.953, P<0.001). Bland-Altman analysis between CT-ECV and MRI-ECV showed a small bias 2.0% (95% limits of agreement:-17.6%-21.6%) in group A, a small bias -0.4% (95% limits of agreement: -13.8%-12.9%) in group B and a small bias -1.8% (95% limits of agreement: -17.4%-13.9%) in group C. The ICC values between 2 observers were 0.877 and 0.945 on CT-ECV and MRI-ECV, respectively. Conclusions:The larger percentage of hyper-enhanced volume on cardiac MR image, the stronger correlation are between the CT-ECV and MRI-ECV. CT-ECV may be taken as an alternative tool for quantitative evaluation of myocardial tissue in patients with heart failure.

The CRISPR/Cas9 gene editing technology directs Cas9 protein to recognize, bind and cleave the target site specifically by using artificial single-guide RNA (sgRNA), through non-homologous end joining or homologous end-recombinant repair mechanisms of cells, which can be engineered to knockout or knock-in of genomes. RIG-I is a pattern recognition receptor that recognizes the 5'-triphosphate-containing RNA in the cytoplasm and activates IRF3/7 and NF-κB by interacting with the downstream signaling molecule MAVS, thus initiating the expression of type I interferons and inflammatory factors. Previous studies found that influenza B virus (IBV) can up-regulate the expression of RIG-I. In the present study, to explore whether RIG-I is the major receptor for IBV to active the antiviral innate immune response and its effect on IBV replication, RIG-I gene in 293T cells was knocked out by CRISPR-Cas9 system, and a stable RIG-I knockout 293T (RIG-I(-/-) 293T) cell line was screened by puromycin pressure. The results of Western blotting showed that RIG-I was not expressed in this cell line after IBV or Sendai virus (SeV) infection, indicating that the RIG-I(-/-) 293T cell line was successfully constructed. The transcription levels of interferons, inflammatory factors and interferon-stimulated genes in RIG-I(-/-) 293T cells which were infected by IBV decreased significantly compared with those in wild-type 293T cells. Moreover, the phosphorylation of p65 and IRF3 were not detected in IBV or SeV infected RIG-I(-/-) 293T cells. It is indicated that the expression of cytokines mainly depends on the RIG-I-mediated signaling pathway at the early stage of IBV infection. Furthermore, the multi-step growth curves of IBV in the wild type and RIG-I(-/-) 293T cells showed that RIG-I inhibited the replication of IBV. Collectively, the RIG-I knockout 293T cell line was successfully constructed. We found that RIG-I is the main receptor for IBV to active the antiviral innate immune response and is critical for inhibiting IBV replication, which lays the foundation for further study of IBV infection mechanism.