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ABSTRACT: Prion diseases are conformational diseases, many factors are involved in altering the conformation of prion, such as RNA,
DNA, pH, and copper etc. However the neurotoxic mechanism of prion diseases is not clear yet. The aim of this study is to
investigate the effect of the nucleoprotein complex of RNA and recombinant ovine prion protein (OvPrPC) on the cultured rat cortical neurons in vitro. Our previous study revealed that the nucleoprotein complex (OvPrPC-RNA) is characterized with high β sheet conformation and proteinase K resistance. Here we found that the OvPrPC-RNA induced marked neuronal cell death by the MTT (3-(4,5-dimethyl-thiazole -2-yl)-2,5-diphenyl –tetrazolium bromide) and
TUNEL (TdT mediated biotin-dUTP nicked-end labeling) assay, and the neurotoxic effects were confirmed by testing the content
of Bcl-2 Associated X protein (Bax) in the immunoprecipitation assay and Western blot assay. Compared to the control group,
there is no significant difference of active Bax or total Bax after RNA alone treatment or OvPrPC alone treatment, but the OvPrPC-RNA induced significant increases of active Bax level, while the contents of total Bax had no obvious changes after OvPrPC-RNA treatment. The results suggested that OvPrPC-RNA is neurotoxic in vitro, which added further evidence to the current understanding of mechanism of cellular injury by
RNA molecules for transformation of the PrPC to PrPSc.
KeywordsPrion–OvPrPC-RNA–Neuronal injury neurotoxicity–Bax
Neurochemical Research 04/2012; 36(10):1863-1869. · 2.24 Impact Factor
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ABSTRACT: We explored the relationship between predicted infarct core, predicted ischemic penumbras and predicted final infarct volumes obtained though apparent diffusion coefficient (ADC)-based method, as well as other clinical variables, and functional outcome.
Patients with acute cerebral ischemic stroke were retrospectively recruited. The National Institutes of Health Stroke Scale score was evaluated at baseline and the modified Rankin Scale (mRS) at day 90. Favorable outcome was defined as an mRS score of 0 to 2, and unfavorable outcome as 3 to 6. Multimodal stroke magnetic resonance imaging was carried out at presentation. The volumes of diffusion-weighted imaging (DWI) and perfusion-weighted imaging (PWI) were measured using the regions of interest (ROI) method. The volumes of predicted infarct core, predicted ischemic penumbra and predicted final infarct were obtained by an automated image analysis system based on baseline ADC maps. The association between baseline magnetic resonance imaging volumes, baseline clinical variables, and functional outcome was statistically analyzed.
The study included 30 males and 20 females (mean±SD age, 56±10 years). Baseline DWI, PWI and PWI-DWI mismatch volumes were not correlated with day-90 mRS (P>0.05). Predicted infarct core, predicted ischemic penumbra and predicted final infarct through ADC-based method were all correlated with day-90 mRS (P<0.05). A better outcome was associated with a smaller predicted volume. Low baseline National Institutes of Health Stroke Scale and recanalization also demonstrated a trend toward a favorable outcome. Receiver operating characteristic analysis showed that the area under the curve of predicted final infarct volume and recanalization were higher with statistical significance (P<0.001).
Predicted volumes obtained from ADC-based methods, especially predicted final infarct volume, as well as baseline National Institutes of Health Stroke Scale and recanalization may have effect on functional outcome in acute ischemic stroke.
Neurological Research 06/2011; 33(5):494-502. · 1.52 Impact Factor
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ABSTRACT: Prion diseases are conformational diseases, many factors are involved in altering the conformation of prion, such as RNA, DNA, pH, and copper etc. However the neurotoxic mechanism of prion diseases is not clear yet. The aim of this study is to investigate the effect of the nucleoprotein complex of RNA and recombinant ovine prion protein (OvPrP(C)) on the cultured rat cortical neurons in vitro. Our previous study revealed that the nucleoprotein complex (OvPrP(C)-RNA) is characterized with high β sheet conformation and proteinase K resistance. Here we found that the OvPrP(C)-RNA induced marked neuronal cell death by the MTT (3-(4,5-dimethyl-thiazole -2-yl)-2,5-diphenyl -tetrazolium bromide) and TUNEL (TdT mediated biotin-dUTP nicked-end labeling) assay, and the neurotoxic effects were confirmed by testing the content of Bcl-2 Associated X protein (Bax) in the immunoprecipitation assay and Western blot assay. Compared to the control group, there is no significant difference of active Bax or total Bax after RNA alone treatment or OvPrP(C) alone treatment, but the OvPrP(C)-RNA induced significant increases of active Bax level, while the contents of total Bax had no obvious changes after OvPrP(C)-RNA treatment. The results suggested that OvPrP(C)-RNA is neurotoxic in vitro, which added further evidence to the current understanding of mechanism of cellular injury by RNA molecules for transformation of the PrP(C) to PrP(Sc).
Neurochemical Research 05/2011; 36(10):1863-9. · 2.24 Impact Factor
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ABSTRACT: Radiofrequency electromagnetic fields (EMF) are harmful to public health, but the certain anti-irradiation mechanism is not clear yet. The present study was performed to investigate the possible protective effects of green tea polyphenols against electromagnetic radiation-induced injury in the cultured rat cortical neurons. In this study, green tea polyphenols were used in the cultured cortical neurons exposed to 1800 MHz EMFs by the mobile phone. We found that the mobile phone irradiation for 24 h induced marked neuronal cell death in the MTT (3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyl-tetrazolium bromide) and TUNEL (TdT mediated biotin-dUTP nicked-end labeling) assay, and protective effects of green tea polyphenols on the injured cortical neurons were demonstrated by testing the content of Bcl-2 Assaciated X protein (Bax) in the immunoprecipitation assay and Western blot assay. In our study results, the mobile phone irradiation-induced increases in the content of active Bax were inhibited significantly by green tea polyphenols, while the contents of total Bax had no marked changes after the treatment of green tea polyphenols. Our results suggested a neuroprotective effect of green tea polyphenols against the mobile phone irradiation-induced injury on the cultured rat cortical neurons.
Neurotoxicity Research 02/2011; 20(3):270-6. · 3.51 Impact Factor
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Li Ma,
Pei-Yi Gao,
Qing-Mao Hu,
Yan Lin,
Li-Na Jing,
Jing Xue,
Xiao-Chun Wang,
Zhi-Jun Chen,
Yi-Long Wang,
Xiao-Ling Liao, Mei-Li Liu,
Wei-Jian Chen
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ABSTRACT: To investigate whether baseline apparent diffusion coefficient (ADC) maps can be employed to predict both infarct core and salvageable ischemic tissue volumes in acute ischemic stroke.
An automated image analysis system based on baseline ADC maps was tested against 30 patients with acute ischemic stroke of anterior circulation to predict both infarct core and salvageable ischemic tissue volumes. The predicted infarct core and predicted salvageable ischemic tissue were quantitatively and qualitatively compared with follow-up imaging data in recanalization and no recanalization groups, respectively. Direct comparisons with perfusion- and diffusion- weighted magnetic resonance imaging measures were also made. Wilcoxon signed-rank test, Spearman rank correlation, and Bland-Altman plots were performed.
In the recanalization group, the predicted infarct core volume was significantly correlated with the final infarct volume (r = 0. 868, P < .001). In the no recanalization group, the predicted final infarct volume (sum of the predicted infarct core and salvageable ischemic tissue volumes), as well as the predicted salvageable ischemic tissue volume, was also significantly correlated with the true final infarct volume (r = 0.955, P < .001) and infarct growth (r = 0.918, P < .001), respectively. The volumes of perfusion-diffusion mismatch were significantly larger than those of infarct growth and predicted salvageable ischemic tissue. Good agreement between predicted and true final infarct lesions was visualized by Bland-Altman plots in two groups. Direct visual comparative analysis revealed good qualitative agreement between the true final infarct and predicted lesions in 21 patients.
The proposed ADC based approach may be a feasible and practical tool to predict the volumes of infarct core and salvageable ischemic tissue without intravenous contrast media-enhanced perfusion-weighted imaging at baseline.
Academic radiology 12/2010; 17(12):1506-17. · 2.09 Impact Factor
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Li Ma,
Pei-Yi Gao,
Yan Lin,
Jing Xue,
Xiao-Chun Wang,
Yong-Jun Wang,
Yi-Long Wang,
Xiao-Ling Liao, Mei-Li Liu,
Shi-Ming Cui,
Lan Yu,
Sui-Jun Tong,
Yuan-Liang Huang,
Yu-Ming Zhou
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ABSTRACT: We investigated whether baseline vessel status evaluated by magnetic resonance angiography (MRA) can be the foremost factor to classify acute ischemic stroke patients into subgroups for thrombolytic therapy within 3-6 hours of symptom onset.
Acute ischemic stroke patients beyond 3 hours after symptom onset were examined by stroke magnetic resonance imaging (MRI) (diffusion- and perfusion-weighted imaging, and MRA) before and after thrombolysis treatment within 24-48 hours. Stroke MRI was used to classify acute ischemic stroke patients into subgroups and select optimal patients for thrombolytic treatment. Clinical scores were compared to determine whether there were significant differences among subgroups.
The difference in day 90 modified Rankin scale (mRS) between treated salvageable and untreated salvageable patients with recombinant tissue plasminogen activator (rt-PA) was remarkably statistically significant (p=0.02). Treated salvageable patients had more favorable clinical outcomes as compared with the untreated salvageable patients. Patients who did not have baseline artery occlusion were associated with more favorable clinical outcomes than untreated salvageable patients (p<0.001). The difference between treated salvageable and patients without artery occlusion in 90 day mRS score was not statistically significant (p=0.058).
Baseline vessel status evaluated by MRA may be used as the first factor ahead of mismatch to categorize acute ischemic stroke patients into subgroups. Patients who do not have initial vessel occlusion may not need thrombolytic therapy.
Neurological Research 05/2009; 31(4):355-61. · 1.52 Impact Factor
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ABSTRACT: To gain insight into the conformational conversion of ovine prion protein (OvPrP(C)) at different pH values and/or in the presence of CuCl(2), the secondary structure of OvPrP(C) was analysed by circular dichroism (CD) spectroscopy. Copper treatment of OvPrP(C) under moderately acidic conditions (pH approximately 5.0-6.0) as well as physiological conditions (pH 7.4) also makes OvPrP(C) adopt protease-resistant and beta-sheet-rich conformation. However, under lower pH conditions (2.0-4.5) with copper treatment, OvPrP(C) gained higher alpha-helix structure. This study demonstrated that Cu(2+) can significantly modulate conformational conversion triggered by acidic pH, and this will provide therapeutic intervention approaches for prion diseases.
Journal of Biochemistry 04/2008; 143(3):333-7. · 2.37 Impact Factor
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ABSTRACT: Neuronal degeneration and astrogliosis are hallmarks of prion disease. Synthetic prion protein (PrP) peptide 106-126 (PrP106-126) can induce death of neurons and proliferation of astrocytes in vitro and this neurotoxic effect depends on the expression of cellular PrP (PrPC) and is hence believed to be PrP(C) -mediated. To further elucidate the involvement of PrPC in PrP106-126-induced neurotoxicity, we determined the expression of PrP mRNA in primary culture of rat cortical neuron cells, cerebellar granule cells, and astrocytes following treatment with 50 microM of PrP106-126 scrambled PrP106-126 by quantitative real-time RT-PCR. As shown by MTT test, PrP106-126 induced significant death of neuron cells and marked proliferation of astrocytes after 10 days of treatment. Under the same treatment regimens, the level of PrP gene expression was significantly down-regulated in cortical neuron cell cultures and cerebellar granule cell cultures and was up-regulated in astrocyte cultures. The altered PrP gene expression occurred as early as 3 days after the treatment. After 10 days of treatment, while the cultured cortical neurons underwent further apoptosis, their expression of PrP gene started to recover gradually. These findings indicate that PrP 106-126 regulates transcription of the PrP gene and this activity is associated with its neurotoxicity in primary rat neuronal cultures.
Cellular and Molecular Neurobiology 01/2006; 25(8):1171-83. · 1.97 Impact Factor
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ABSTRACT: To observe the morphological changes of Balb/C mouse embryonic stem cells following directed differentiation into pancreatic islet-like cell clusters (PICC) in vitro using atomic force microscope (AFM).
Balb/C mouse embryonic stem cells were first cultured into embryonic bodies (EBs) and allowed to differentiate spontaneously for 4 days. The cells were then transferred to gelatin-coated dishes for the EBs to attach and spread on the tissue culture plates, in the course of which a series of cell growth factors such as basic fibroblast growth factor (bFGF), insulin-like growth factor 1 (IGF-1) and nicotinamide were added into the culture medium at specific time points to induce directed differentiation of the stem cells into PICC. Immunocytochemistry was employed to detect the cells positive for insulin and glucagon, which were observed with AFM.
The embryonic stem cells developed into cell clusters of different sizes, in which the cells were tightly arranged. Islet B cells were numerous in the center of clusters and darkly stained, but fewer in the peripherals with lighter stains. Islet A cells expressing glucagon were relatively fewer in the cell clusters, found mainly in the peripherals. Scanning of the insulin-positive clusters by AFM revealed large quantity of tissue fibers resembling nerve fibers that formed a reticular structure in disorderly arrangement. Numerous round granules were observed in the cytoplasm of almost identical sizes ranging from 0.5 to 1.0 mum in diameter.
The cell clusters obtained by directed differentiation are mature in both morphology and function with also well organized structures.
Di 1 jun yi da xue xue bao = Academic journal of the first medical college of PLA 05/2005; 25(4):377-9, 402.
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ABSTRACT: Human CD34(+) hematopoietic cells, a distinctive cell population containing hematopoietic stem/progenitor cells (HSPC), have the capability to highly self-renewal, differentiation into all lineages of committed progenitor cells and reconstitution of both long-term hematopoiesis and immunefunctions after transplantation. CD34(+) hematopoietic cells from bone marrow (BM) recently have been employed for treating neoplastic and genetic disorders. This study was aimed to investigate membrane surface ultrastructures of bone marrow CD34(+) cell from mormal persons and leukemia patients and to compare their morphologic differences by using atomic force microscope (AFM). BM was collected from 5 normal donors and 6 leukaemia patients. All samples were layered on Ficoll-Paque gradients (specific gravity 1.077 g/ml) to separate the mononuclear cells. After that CD34(+) cells were purified by immuno-magnetic bead separation and evaluated with a FACS Calibur, these cells were detected by AFM of tapping mode inair. At lest 20 cells per samples were observed. The results showed that most of CD34(+) hematopoietic cells were like circle plate, the diameter was 10 - 14 microm. The surface of CD34(+) hematopoietic cell membrane was comparatively complex. The surface of CD34(+) hematopoietic cell membrane appeared as granular, with packed particles. With the region analysis function of IP2.1 software, the region of 2 microm x 2 microm was selected and four parameters of the surface (maximum peak-to-valley distance, average roughness, root-mean-squared roughness and mean height) were measured. Values of the 4 parameters showed that the characteristic parameters of CD34(+) HSPC from leukaemia were higher than that from normal person. It is concluded that AFM has specific advantages in analyzing cell membrane in the nanometer level and can gain more information. With the help of analysis software, AFM can be a helpful tool for fast leukaemic diagnosis and CD34(+) hematopoietic cells selection.
Zhongguo shi yan xue ye xue za zhi / Zhongguo bing li sheng li xue hui = Journal of experimental hematology / Chinese Association of Pathophysiology 01/2005; 12(6):793-7.
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ABSTRACT: To observe the difference in surface morphology and structure between CD34(+) cells from normal human subjects and from patients with leukemia.
Bone marrow mononuclear cells from 3 normal human subjects and 3 patients with M2b leukemia were collected by Percoll gradient centrifugation, followed by purification of CD34(+) cells by means of immunomagnetic bead separation (MiniMAC) and examination with flow cytometry. The morphology of the cells were then observed with optical and atomic force microscope (AFM) in air.
No significant difference was identified between the two cells under optical microscope. With atomic force microscope, numerous microvilli were observed on the surface of CD34(+) cells, and the normal cells and those from the leukemic patients showed significant difference in terms of the roughness of the cell surface.
Normal CD34(+) cells have more rough and erosive surface structure than leukemic CD34+ cells (M2b).
Di 1 jun yi da xue xue bao = Academic journal of the first medical college of PLA 01/2004; 23(12):1270-2.
