Classification-based framework for binarization on mice eye image in vivo with optical coherence tomography.

Optical coherence tomography (OCT) angiography has drawn much attention in the medical imaging field. Binarization plays an important role in quantitative analysis of eye with optical coherence tomography. To address the problem of few training samples and contrast-limited scene, we proposed a new binarization framework with specific-patch SVM (SPSVM) for low-intensity OCT image, which is open and classification-based framework. This new framework contains two phases: training model and binarization threshold. In the training phase, firstly, the patches of target and background from few training samples are extracted as the ROI and the background, respectively. Then, PCA is conducted on all patches to reduce the dimension and learn the eigenvector subspace. Finally, the classification model is trained from the features of patches to get the target value of different patches. In the testing phase, the learned eigenvector subspace is conducted on the pixels of each patch. The binarization threshold of patch is obtained with the learned SVM model. We acquire a new OCT mice eye (OCT-ME) database, which is publicly available at https://mip2019.github.io/spsvm. Extensive experiments were performed to demonstrate the effectiveness of the proposed SPSVM framework.

Establishment and application of a loop-mediated isothermal amplification method for simple, specific, sensitive and rapid detection of Toxoplasma gondii.

The Loop-mediated isothermal amplification (LAMP) method amplifies DNA with high simply, specificity, sensitivity and rapidity. In this study, A LAMP assay with 6 primers targeting a highly conserved region of the GRA1 gene was developed to diagnose Toxoplasma gondii. The reaction time of the LAMP assay was shortened to 30 min after optimizing the reaction system. The LAMP assay was found to be highly specific and stable. The detection limit of the LAMP assay was 10 copies, the same as that of the conventional PCR. We used the LAMP assay to develop a real-time fluorogenic protocol to quantitate T. gondii DNA and generated a log-linear regression plot by plotting the time-to-threshold values against genomic equivalent copies. Furthermore, the LAMP assay was applied to detect T. gondii DNA in 423 blood samples and 380 lymph node samples from 10 pig farms, and positive results were obtained for 7.8% and 8.2% of samples, respectively. The results showed that the LAMP method is slightly more sensitive than conventional PCR (6.1% and 7.6%). Positive samples obtained from 6 pig farms. The LAMP assay established in this study resulted in simple, specific, sensitive and rapid detection of T. gondii DNA and is expected to play an important role in clinical detection of T. gondii.

[Expression level of Th22 cells and its cytokines in patients with acute lymphoblastic leukemia and its significance].

This study was purposed to analyze the expression level of Th22 cells and their cytokines in patients with acute lymphoblastic leukemia (ALL) and evaluate its significance. Forty-eight patients with ALL were selected. According to the treatment, all patients were divided into the newly diagnosed group (n = 26) and complete remission (CR) group (n = 22). The proportion of Th22 cells in peripheral blood was detected by flow cytometry (FCM). The expression levels of cytokines IL-22, IL-6, TNF-α and TGF-ß in peripheral blood were measured by ELISA. The expression level of IL-22 mRNA in peripheral blood mononuclear cells was examined by semi-quantitative-reverse transcription PCR (RT-PCR). Meanwhile, 30 healthy individuals were selected as a control group. The parameters of the 3 groups were compared. The results showed that the percentage of Th22 cells and the expression levels of IL-22, IL-6, TNF-α and IL-22 mRNA in newly diagnosed group and the CR group were significantly lower than that in control group, the expression level of TGF-ß in above mentioned two group was obviously higher than that in control group (P < 0.05). The percentage of Th22 cells and the expression levels of IL-22, IL-6, TNF-α and IL-22 mRNA in newly diagnosed group were evidently lower than that in CR group (P < 0.05), but the expression level of TGF-ß in newly diagnosed group obviously higher than that in CR group. The expression level of IL-22 in newly diagnosed group was positively related with expression level of IL-6 and TNF-α, but it was negatively related with expression level of TGF-ß. It is concluded that the decreasing of Th22 cells and down-regulation of IL-22 expression level may be related with pathogenesis of ALL, the decreasing of Th22 cells is risk factor for ALL.

Effects of transplantation with bone marrow-derived mesenchymal stem cells modified by Survivin on experimental stroke in rats.

BACKGROUND: This study was performed to determine whether injury induced by cerebral ischemia could be further improved by transplantation with bone marrow-derived mesenchymal stem cells (MSCs) modified by Survivin (SVV). METHODS: MSCs derived from bone marrow of male Sprague-Dawley rats were infected by the self-inactive lentiviral vector GCFU carrying green fluorescent protein (GFP) gene and SVV recombinant vector (GCFU-SVV). In vitro, vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) were detected in infected MSCs supernatants under hypoxic conditions by ELSIA. In vivo, experiments consisted of three groups, one receiving intravenous injection of 500 µl of phosphate-buffered saline (PBS) without cells (control group) and two groups administered the same volume solution with either three million GFP-MSCs (group GFP) or SVV/GFP-MSCs (group SVV). All animals were submitted to 2-hour middle cerebral artery occlusion (MCAO) and then reperfusion. Differentiation and survival of the transplanted MSCs were determined by confocal microscope. Western blot was used to detect the expression of VEGF and bFGF in ischemic tissue. A 2,3,5-triphenyltetrazolium chloride (TTC) staining was used to assess the infarct volume. Evaluation of neurological function was performed using a modified Neurological Severity Score (mNSS). RESULTS: In vitro, modification with SVV further increased secretion of VEGF and bFGF under hypoxic condition. In vivo, only very few transplantated cells co-expressed GFP and NeuN. The survival transplanted cells in the group SVV was 1.3-fold at 4 days after transplantation and 3.4-fold higher at 14 days after transplantation, respectively, when compared with group GFP. Expression of VEGF and bFGF in the ischemic tissue were further up-regulated by modification with SVV. Moreover, modification with SVV further reduced the cerebral infarct volume by 5.2% at 4 days after stroke and improved post-stroke neurological function at 14 days after transplantation. CONCLUSION: Modification with SVV could further enhance the therapeutic effects of MSCs possibly through improving the MSCs survival capacity and up-regulating the expression of protective cytokines in the ischemic tissue.