Biomedical subjects

Xiaofeng Lu

Publications and source records attributed to Xiaofeng Lu.

30 records · Page 2Linked to original sources

PubMed2003

[Proteomics analysis and biochemical activity detection on facial nerve regeneration fluid].

OBJECTIVE: To explore the protein components and the biological neutrional activity upon motor neuron, so that take a general, basic study on the nerve regeneration microenvironment which be important to facial nerve regeneration. METHOD: The animal model of rabbit facial regeneration microenvironment is established. Advanced technology of two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) was used to study on the structural proteins in the regeneration fluid, as well as the motor neuron culture was used to test the biological activity in it. RESULT: 850 +/- 78 protein spots were detected in the regeneration fluid. The body area, neurite length and OD value of experimental group are higher than that of control group. CONCLUSION: We got the protein image of facial nerve regeneration fluid by 2-D PAGE, and proved that many kinds and number of proteins in the regeneration fluid have neutrional activity on motor neuron.

Animals↗

PubMed2003

[Study on rabbit mesenchymal stem cells differentiation to the adipogenic or osteogenic lineage in vitro].

Rabbit bone marrow-derived mesenchymal stem cells(MSCs) are multipotent. We studied the adipogenic and osteogenic differentiation potent using adipogenic supplement (AS) or osteogenic supplement (OS) in vitro. Specific markers of this induced adipogenic and osteogenic lineage were identified. The findings showed that the rabbit MSCs are capable of differentiating into adipogenic and osteogenic lineages spontaneously. On the 21st day, approximately 75% rabbit MSCs were induced to adipogenic or osteogenic cells in medium containing AS or OS, respectively. These results demonstrated that the differentiation of MSCs could be regulated in vitro. The underlying molecular mechanisms of adipogenic or osteogenic differentiation await elucidation.

Adipose Tissue↗

PubMed2003

[Biological characteristics of human umbilical artery smooth muscle cells cultured in vitro and the preestablishment of immortalized cell line].

OBJECTIVE: To establish the best primary and propagated culture approach of the human umbilical artery smooth muscle cells (HUASMC) and immortalized the primary cells. METHODS: The primary culture of HUASMC was performed using the primary-explant method, and the effects on the cells' growth characteristic by different culture mediums were conducted. Primary cultures of HUASMC derived from normal human umbilical arteries were transfected with recombination plasmid containing human telomerase reverse transcriptase (hTERT) open reading frame. The transfected HUASMC was analyzed for cell biological characteristics, and growth characteristics, and specific alpha-actin. RESULTS: Highly purified primary HUASMC were gained and could be propagated about 10 population doublings (PD). After PD 4, the cells lost the proliferation ability gradually. However, the transfected HUASMC could be propagated at least 20 population doublings and could express specific alpha-actin. CONCLUSION: The hTERT transfected HUASMC could keep the basic biological characteristic of smooth muscle cells and prolonged life span at least 20 PD. It might be a good cell model for the study of cardiovascular disease, myoma of uterus and chronic graft disfunction. It might also bring the hope to engineered vascularization in the future.

Cell Line↗

PubMed2003

[Preliminary identification of up-regulated genes after the interaction of human peripheral blood mononuclear cell and porcine endothelial cell].

OBJECTIVE: To investigate the change of gene expression after the interactions of human peripheral blood mononuclear cell (PBMC) and porcine endothelial cell. METHODS: Human PBMC were co-cultured with porcine vascular endothelial cell line PIEC for 18 h. The mixed un-co-cultured PBMC and PIEC were used as controls. The cDNAs of both groups were prepared and subtracted by suppression subtractive hybridization (SSH). The up-regulated cDNAs were cloned into pGEM-T Easy vector to be sequenced. Nucleic acid homology searches were performed using the BLAST program. RESULTS: A subtracted cDNA library was obtained through SSH and cloning, which included about 300 clones corresponding to up-regulated genes. We randomly selected 24 of these clones for sequencing tests and analysis of homology in the GenBank. Four of the 24 clones were part of known human genes, 8 were known porcines expressed sequence tag (EST), and 9 held similar homology with known human genes. Three clones were not matched. CONCLUSION: Many genes are up-regulated after the interaction of human PBMC and porcine endothelial cell.

Animals↗

PubMed2003

[Inhibition property of a polypeptide APS against phytopathogenic fungi and the possible antifungal mechanism].

OBJECTIVE: To investigate the inhibition property of a novel antifungal polypeptide APS in vitro and its possible antifungal mechanism. METHODS: The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of APS against different fungi were detected by microdilution test. And the voltaic change of planar lipid bilayer was observed during APS treatment. RESULTS: APS at low MIC and MBC was shown to have effects on phytopathogenic fungi tested except aspergillus fumigatus, the minimum values of MIC and MBC being 1.43 micrograms/ml and 1.78 micrograms/ml respectively. After APS was put in, the transmembrane current could be recorded. CONCLUSION: APS has strong inhibitory effects on the germination of spores of several phytopathogenic fungi. Its antifungal mechanism is likely to form persistent pores on the cell membrane, thus causing membrane permeation and the death of fungi.

Anti-Bacterial Agents↗

PubMed2003

[Using two-dimensional gel electrophoresis to analyze the regeneration microenvironment of facial nerve and its response to acupuncture].

OBJECTIVE: To investigate the distribution of proteins in the regeneration microenvironment of facial nerve and its response to acupuncture. METHODS: We created an animal model using rabbit to imitate the regeneration microenvironment of facial nerve and analyzed the proteins in the microenvironment through the two-dimensional gel electrophoresis. RESULTS: We found that most proteins in the regeneration fluid were under relative molecular mass 80 x 10(3) and in the range of pI 4-7. An average of 800 +/- 53 protein spots was found in the control group compared to the 850 +/- 78 spots in the acupuncture group. In the matching spots, more than ten proteins were different between the two groups. CONCLUSION: There is no evidence to show that acupuncture has a positive effect on the regeneration microenvironment of facial nerve.

Acupuncture↗

PubMed2003

[Bactericidal peptide targeted against penicillin/methicillin-resistant Staphylococcus aureus--an engineered multidomain protein machine].

OBJECTIVE: To construct a targeting bactericidal peptide machine by fusing two minidomains with different bioactivities and different protein origins. METHODS: Such fusion peptide was constructed by linking the gene of Staphylococcal AgrD pheromone with the gene of C-terminal (I626) of colicin Ia pore-forming region (K544-I626) with site-directed mutation. Mutated plasmid was transformed into E. coli TG1 cells to produce fusion peptide, peptides were purified by CM sepharose ion-exchange column. In vitro bactericidal assays were made to identify the bioactivity of fusion peptide. RESULTS: Fusion peptide presented a specific bactericidal activity which was over one hundred times as effective as that of penicillin/oxacillin against tested Staphylococcus aureus strains. CONCLUSION: Fusion peptide behaved with a targeting bactericidal activity against Staphylococcus aureus which was lacking at two precursors, Staphylococcal pheromone and colicin Ia pore-forming region. These results suggest that an engineered multidomain protein machine with specific bactericidal activity has been constructed in the present study.

Anti-Bacterial Agents↗

PubMed2002

Differential activation of monkey striatal neurons in the early and late stages of procedural learning.

The basal ganglia is a key structure for procedural learning. To examine in what aspects of procedural learning the basal ganglia participate, we recorded from striatal neurons (phasically active neurons) in monkeys while the animals were performing a sequential button press task (the 2 x 5 task) and compared the neuronal activity between two conditions: (1) while learning new sequences and (2) while executing overlearned sequences. Among 147 neurons recorded in two monkeys, 45 neurons were activated preferentially for new sequences (new-preferring neurons), 34 for overlearned sequences (learned-preferring neurons), and 68 were activated non-selectively (non-selective neurons). New-preferring neurons were more abundant in the "association" region [association striatum (AS); caudate nucleus and rostral putamen anterior to the anterior commissure], while the learned-preferring neurons were more abundant in the "sensorimotor" region [sensorimotor striatum (SM); putamen posterior to the anterior commissure]. In addition to the learning dependency, the AS and SM neurons were activated in different task periods: many AS neurons were activated during the delay period, while the SM neurons were more activated with reaching and button presses. These data, together with the data from our previous blockade study, suggest that the "association" and "sensorimotor" regions of the basal ganglia contribute preferentially to the early and late stages of procedural learning, respectively.

Animals↗

PubMed2002

A neural correlate of oculomotor sequences in supplementary eye field.

Complex learned motor sequences can be composed of a combination of a small number of elementary actions. To investigate how the brain represents such sequences, we devised an oculomotor sequence task in which the monkey had to choose the target solely by the sequential context, not by the current stimulus combination. We found that many neurons in the supplementary eye field (SEF) became active with a specific target direction (D neuron) or a specific target/distractor combination (C neuron). Furthermore, such activity was often selective for one among several sequences that included the combination (S neuron). These results suggest that the SEF contributes to the generation of saccades in many learned sequences.

Animals↗

PubMed2002

[The actuality and trend of biomaterial effectiveness and safety evaluation].

The evaluation of biomaterial effectiveness and safety is a key step before the biomaterial approaches to clinics. In recent years, lots of new biomaterials with different composition, shape, implant site and use have been coming out and in need of more special, sensitive and systematic evaluation methods. With the development of immunology, microdetective technique, inbred strain mammal and other connective branches, there are many chances for the consummation and integration of biomaterial evaluation system. The three-"R" principle (replace, refine, reduce), that is, developing in vitro experiments, using sensitive, special and advanced evaluation methods, improving and reducing the member of experimental animals, as well as the fundamental rule, that is, establishing an evaluation system covering three levels (molecule, cell and body) will guide the research of biomaterial evaluation to more promising development.

Animals↗

PubMed2002

[Bone marrow mesenchymal stem cells: progress in bone/cartilage defect repair].

Mesenchymal stem cells (MSC) are thought to be multi-potent cells that have the potential to differentiate into lineages of mesenchymal tissues, including bone, cartilage, tendon, fat, muscle, and marrow stroma during embryo morphogenesis. In recent years, cells that have the characteristics of mesenchymal stem cells were isolated from marrow aspirates of human and a few animals. It was found that these cells retain the characteristics of stem cells in vitro and could be induced to differentiate exclusively into the osteocytic, chondrocytic, myoblastic and adipocytic lineages. It was demonstrated that MSC could heal clinically significant bone and cartilage defects in animal models. The role of MSC in repairing tendon defect was also testified. In addition, for its multi-potential to differentiate into lineages of mesenchymal tissues, MSC could be used as gene vehicle for gene therapy of trauma care.

Animals↗

PubMed2002

[Osteogenesis of HA/TCP biphasic ceramics implanted into muscle: a long-term study].

New bone formation in long-term intramuscle implant of Ca-P biomaterial was investigated in this experiment. After implanting into dog dorsal muscle for 15 months, a thin fibrous membrane that wrapped HA/TCP implant was still observed obviously. Three types of tissues, i.e. mesenchymal tissue, bone and bone marrow, regularly distributed in different pores of implant. Nearly all the pores of implants were occupied by bone. Bone in the pores located in the central region of implant was matured lamellar bone characterized by obvious lacuna and rich bone marrow. However, bone in the peripheral pores was immature woven bone without bone marrow formation. Furthermore, mesenchymal tissues only exist in the peripheral pores and usually were connected with immature woven bone. It was demonstrated that porous HA/TCP has bone inductivity and it could induce new bone formation at non-osseous site. Well-regulated distribution of mesenchymal tissue, bone and bone marrow in the pores suggest bone morphogenesis in the implant must obey a specific space-time program.

Animals↗