A region-level contrastive learning-based deep model for glomerular ultrastructure segmentation on electron microscope images / 南方医科大学学报

OBJECTIVE@#We propose a novel region- level self-supervised contrastive learning method USRegCon (ultrastructural region contrast) based on the semantic similarity of ultrastructures to improve the performance of the model for glomerular ultrastructure segmentation on electron microscope images.@*METHODS@#USRegCon used a large amount of unlabeled data for pre- training of the model in 3 steps: (1) The model encoded and decoded the ultrastructural information in the image and adaptively divided the image into multiple regions based on the semantic similarity of the ultrastructures; (2) Based on the divided regions, the first-order grayscale region representations and deep semantic region representations of each region were extracted by region pooling operation; (3) For the first-order grayscale region representations, a grayscale loss function was proposed to minimize the grayscale difference within regions and maximize the difference between regions. For deep semantic region representations, a semantic loss function was introduced to maximize the similarity of positive region pairs and the difference of negative region pairs in the representation space. These two loss functions were jointly used for pre-training of the model.@*RESULTS@#In the segmentation task for 3 ultrastructures of the glomerular filtration barrier based on the private dataset GlomEM, USRegCon achieved promising segmentation results for basement membrane, endothelial cells, and podocytes, with Dice coefficients of (85.69 ± 0.13)%, (74.59 ± 0.13)%, and (78.57 ± 0.16)%, respectively, demonstrating a good performance of the model superior to many existing image-level, pixel-level, and region-level self-supervised contrastive learning methods and close to the fully- supervised pre-training method based on the large- scale labeled dataset ImageNet.@*CONCLUSION@#USRegCon facilitates the model to learn beneficial region representations from large amounts of unlabeled data to overcome the scarcity of labeled data and improves the deep model performance for glomerular ultrastructure recognition and boundary segmentation.

Multiple transmission electron microscopic image stitching based on sift features / 南方医科大学学报

We proposed a new stitching method based on sift features to obtain an enlarged view of transmission electron microscopic (TEM) images with a high resolution. The sift features were extracted from the images, which were then combined with fitted polynomial correction field to correct the images, followed by image alignment based on the sift features. The image seams at the junction were finally removed by Poisson image editing to achieve seamless stitching, which was validated on 60 local glomerular TEM images with an image alignment error of 62.5 to 187.5 nm. Compared with 3 other stitching methods, the proposed method could effectively reduce image deformation and avoid artifacts to facilitate renal biopsy pathological diagnosis.

Effect of Sanqi Oral Liquid on Podocytes and Slit Diaphragm-associated Molecules Expression in Diabetes Mellitus Rats After Unilateral Nephrectomy / 广州中医药大学学报

Objective To observe the effect of Sanqi Oral Liquid on the podocytes and the expression of slit diaphragm-associated molecules (including Nephrin, Podocin and CD2AP proteins) of diabetes mellitus (DM) rats after unilateral nephrectomy, so as to explore its mechanism for protecting renal function. Methods SD male rats were randomized into sham operation group, model group and Chinese medicine group. The experimental diabetes mellitus ( DM) model was given unilateral nephrectomy and intraperitoneal injection of 35 mg/kg of streptozocin (STZ). And then the model rats were given intragastric administration of Sanqi Oral Liquid (2.5 g· kg-1·d-1) and the same volume distilled water respectively for 8 weeks. After treatment, the density of podocytes and the podocytic foot process width of different groups were measured. Immunohistochemistry was used to observe the changes of the expression of Nephrin, Podocin and CD2AP in renal tissues of different groups. Results After treatment with Sanqi Oral Liquid, the density of podocytes was increased, the foot process lesion was relieved, and the expression levels of Nephrin, Podocin and CD2AP proteins were increased (P<0.05 or P<0.01 as compared with those in the model group). Conclusion The protective mechanism of Sanqi Oral Liquid for renal function of unilateral nephrectomy DM rats is possibly related with the alleviation of podocyte injury and with the regulation of the expression of Nephrin, Podocin and CD2AP proteins in podocytes.

Effect of miRNA on radiosensitivity and chemosensitivity in glioma stem cells / 国际肿瘤学杂志

The expression of microRNA (miRNA) is closely related to radio-chemosensitivity in glioma stem cells (GSCs).Moreover,the growth of glioma stem cells could be inhibited comprehensively by increasing radio-chemosensitivity and apoptosis,simultaneously with the regulation of a single miRNA,which has been confirmed by some researches.Thereby microRNA is prospective for the adoption as a specific agent in targeted therapy of glioma,so as to increase the radio-chemosensitivity in glioma stem cells.

Preventive effect of calcium channel blocker in tacrolimus induced nephrotoxicity in rats / 中华泌尿外科杂志

Objective To study the calcium metabolism in tacrolimus(FK506)induced rats nephrotoxicity and the preventive effect of calcium channel blocker.Methods Twenty-four Spragueinduced or FK506-induced nephropathy model.Blood creatinine,blood electrolytes,renal tissue histopathology(HE stain)and the change of ultrastructural organization in renal cells by transmission electron microscope were observed.Results The blood creatinine levels of both CsA and FK506 groups [(36.00±2.61)and(34.17±4.54)μmol/L] were significantly higher than those of the FK506+Dilgroup and control group(all P＜0.05).The blood calcium levels of both CsA and FK506 groups (2.00±0.04 and 2.05±0.04 mmol/L) were significantly lower than those of the FK506+Dil group and control group(all P＜0.05).The blood creatinine and calcium levels of FK506+Dil group were not significantly different with those of control group(P＞O.05).Histopathology examination showed cloudy swelling and vacuolization of the renal tubular epithelial cells and intra-cellular mitochondria swelling and vacuolization in the CsA and FK506 groups.However,the pathological changes of the FK506+Dil group were remarkably milder in comparison with the CsA and FK506 groups.Concluum channel blocker,Dil,could prevent the FK506-induced nephrotoxicity.

Culture and pluripotentiality of human marrow mesenchymal stem cells / 中华血液学杂志

<p><b>OBJECTIVE</b>To cultivate human mesenchymal stem cells (MSC) derived from fetal bone marrow and examine their pluripotentiality.</p><p><b>METHODS</b>Bone marrow mononuclear cells from human fetal femur were collected by Percoll gradient centrifugation. The low density cells including MSCs were cultivated and expanded in MSCGM media. The characteristics of the multipotent MSCs were observed by implanting them into nude mice for 4 weeks.</p><p><b>RESULTS</b>Human fetal marrow MSCs were successfully cultivated and differentiated in vivo into many kinds of tissues such as bone, cartilage, adipose, skeletal muscle and tendon-like tissue.</p><p><b>CONCLUSION</b>Human fetal marrow MSCs were multipotent stem cells.</p>