Physiological and pathological insights into exosomes in the brain.

Exosomes are small vesicles secreted by all cell types in the brain and play a role in cell-cell communication through the transfer of cargo or encapsulation. Exosomes in the brain have considerable impact on neuronal development, activation, and regeneration. In addition, exosomes are reported to be involved in the onset and propagation of various neurodegenerative diseases.

Research on DNA methylation of human osteosarcoma cell MGMT and its relationship with cell resistance to alkylating agents.

The objective of this study was to explore the O(6)-methylguanine-DNA methyltransferase (MGMT) gene methylation status and its protein expression, as well as the effects of demethylating agent 5-Aza-2'-deoxycytidine (5-Aza-CdR) on MGMT gene expression and its resistance to alkylating agents, and to elucidate MGMT expression mechanism and significance in osteosarcoma. The human osteosarcoma cell lines Saos-2 and MG-63 were collected and treated with 5-Aza-CdR for 6 days. The cells not treated with 5-Aza-CdR were set as a negative control.

Experimental investigation of HGF inhibiting glial scar in vitro.

To study the inhibitory effect of Hepatocyte growth factor (HGF) on the responsive hyperplasia of damaged astrocytes in vitro. We prepared damaged model of astrocytes to simulate the responsive hyperplasia of damaged astrocytes in vivo by culturing astrocytes in vitro; After the first day of Ad-HGF transfection, astrocytes were scratched, then after the first, the third, and the fifth day of scratch, we detect the expression amount of astrocytes specific glial fibrillary acidic protein (GFAP) and the ratio of S-phase cells with flow cytometry, both of which can reflect the proliferation status of damaged astrocytes; After HGF was added in scratched astrocytes, the activity of SPK and MAPK (P42/44) were detected by autoradiography and immunoblotting test; After adding different concentrations of HGF protein in astrocytes cultured in different serum concentrations and adding diverse concentrations of HGF protein, SPK and SPK inhibitor DMS in scratched astrocytes, we detect cell proliferation with 3H-TDR incorporation. The first day after Ad-HGF transfected astrocytes were scratched, the amount of GFAP secreted by astrocytes were decreased significantly (P < 0.

[Relationship of motor deficits and imaging features in metastatic epidural spinal cord compression].

Objective: To explore the relationship of motor deficits of the lower extremities with the imaging features of malignant spinal cord compression (MESCCs).

Methods: From July 2006 through December 2008, 56 successive MESCC patients were treated at our department. All were evaluated by magnetic resonance imaging and computed tomography and were scored according to motor deficits Frankel grading on admission.

[Intraarterial neoadjuvant chemotherapy for extremity osteosarcoma].

Objective: To summarize the experiences in intraarterial neoadjuvant chemotherapy for extremity osteosarcoma.

Methods: Between January 2002 and December 2007, 111 patients with stage IIB extremity osteosarcoma received preoperative intraarterial chemotherapy after placing chemotherapy pump subcutaneously, en bloc resection and postoperative adjuvant chemotherapy. There were 63 males and 48 females with an average age of 18 years old (range: 14 - 39).

NMDA receptor antagonist MK-801 reduces neuronal damage and preserves learning and memory in a rat model of traumatic brain injury.

Objective: NMDA receptor channel plays an important role in the pathophysiological process of traumatic brain injury (TBI). The present study aims to study the pathological mechanism of TBI and the impairment of learning and memory after TBI, and to investigate the mechanism of the protective effect of NMDA receptor antagonist MK-801 on learning and memory disorder after TBI.

Methods: Forty Sprague-Dawley rats (weighing approximately 200 g) were randomized into 5 groups (n = 8 in each group): control group, model group, low-dose group (MK-801 0.

[Secretion expression in Pichia pastoris and immunogenicity comparison of two forms of HBsAg/GM-CSF fusion proteins].

Aim: To express two fusion forms of hepatitis B virus surface antigen (HBsAg-s and s-HBsAg) in the Pichia pastoris expression system, and compare immunogenicity of the two fusion proteins.

Methods: Was fused GM-CSF to 5' or 3' terminal of HBsAg by inserting the gene fragment of connecting peptide (Gly(4)Ser)(3) to linker gene of GM-CSF and HBsAg. The two fusion proteins were expressed by secreting type expression plasmid pPIC9K in the Pichia pastoris, then the expressed products were detected by SDS-PAGE, Western blot and purified by DEAE-Sepharose Fast Flow ion exchange columns.

Enhancement of DNA vaccine-induced immune responses by a 72-bp element from SV40 enhancer.

Background: Although DNA vaccine is considered as the next generation of vaccine, most DNA vaccine candidates are still suffering from the relatively weak immunogenicity despite the increased dosage of plasmid DNA administered. In order to enhance the immune responses elicited by a codon-optimized HIV gag DNA vaccine, a modified plasmid vector pDRVI1.0 and a booster immunization with replicating Tiantan vaccinia (RTV) strain expressing the same gene were employed.