Biomedical subjects

Yong Liu

Publications and source records attributed to Yong Liu.

At least 73 records · Page 4Linked to original sources

PubMed2006

[Pharmaphylogenetic study on isopyroideae (Ranunculaceae)].

OBJECTIVE: To study the pharmaphylogenetic of medicinal plants of Isopyroideae (Ranunculaceae). METHOD: Comprehensively analyze the correlation between phylogeny, chemical constituents and pharmaceutical aspects of Isopyroideae plants, based on chemical, pharmaceutical (both ethnopharmacologic and pharmacological) information, linking with different plant systems of Ranunculaceae. RESULT: Plants from Aquilegia mainly contain flavonoids constituents while the major chemical constituents of Isopyrum are bisbenzylisoquinoline alkaloids. Chemical characteristics also support that this taxon should be separated from Thalictrodeae, and constituted an independent subfamily, namely, Isopyroideae.

Anti-Infective Agents↗

PubMed2006

[HPLC determination of caffeic acid in herba Lycopi].

OBJECTIVE: To provide experimental data for the quality control of processed Paeonia lactiflora, a Chinese herbal medicine. METHOD: Traditional processing of P. lactiflora was simulated, content of paeoniflorin and water extracts among different preparations were assayed by HPLC; The quantitative correlations among different processing conditions were analyzed, the effects of processing parameters on the contents of paeoniflorin and water extracts were assayed and analysed. RESULT AND CONCLUSION: The controlled processing parameters were correlated with covariables which showed that processing procedures was controllable, and the heating temperature was a factor impacting the content of paeoniflorin.

Caffeic Acids↗

PubMed2006

[Effects of ligustrazine on hippocampal dentate gyrus cell proliferation after focal cerebral ischemia in adult rats].

OBJECTIVE: To explore the effects of ligustrazine on cell proliferation in hippocampal dentate gyrus subgranular zone (SGZ) after focal cerebral ischemia in adult rats. METHODS: Middle cerebral artery occlusion (MCAO) model was established in adult rats by placement of an intraluminal filament at the origin of the MCA. Ligustrazine was administered intraperitoneally at a daily dose of 80 mg/kg starting at 2 h after MCAO, and BrdU (50 mg/kg daily) was also injected intraperitoneally starting at 4 h after MCAO. BrdU-positive cells in the SGZ were counted 7, 14 and 24 days after MCAO, respectively. RESULTS: Compared with sham operation group, ischemic ipsilateral BrdU-positive cells in the ischemic model group increased 7 days after MCAO, reaching the peak on day 14, and decreased on day 21 (P<0.01). The number of ischemic ipsilateral BrdU-positive cells in ligustrazine group was significantly greater than that in the ischemic model group on days 7, 14 and 21 (P<0.01), and maintained the high level on day 21. CONCLUSION: Ligustrazine possesses long lasting effect of promoting cell proliferation in the SGZ after focal cerebral ischemia in adult rats.

Animals↗

PubMed2006

Early total hip arthroplasty for severe displaced acetabular fractures.

OBJECTIVE: To investigate the effect of early total hip arthroplasty for severe displaced acetabular fractures. METHODS: Total hip arthroplasty was performed on 17 cases of severe fracture of the acetabulum from 1997 to 2003. The mean follow-up was 2.1 years (1-6 years) and the average period from fracture to operation was 8 days (5-21 day). The average age of the patients was 53 years (26-69 years). RESULTS: At the final follow-up the Harris hip score averaged 82 (69-100) points and 15 cases have got a good outcome. There was one case of heterotopic bone formation. There were no radiographic evidences of late loosening of the prosthesis. One patient had severe central displacement of the cup. CONCLUSIONS: In patients with severe displaced acetabular fractures, particularly in elderly patients, early total hip arthroplasty is probably an alternative efficient way to achieve a painless and stable hip.

Acetabulum↗

PubMed2006

[Triplex-forming oligonucleotide inhibits the expression of tissue factor gene in endothelial cells induced by the blood flow shear stress in rats].

AIM: To study the effect of antiparallel phosphorothioate triplex-forming oligonucleotide (apsTFO) matching with the shear stress response element (SSRE) of tissue factor (TF) gene promoter region on the expression of TF in endothelial cells (ECs) of rat common carotid artery stenosis. METHODS: The model of common carotid artery middle segment stenosis was established by silica gel pipe loop ligation in SD rats. The mRNA expression and protein synthesis of TF, early growth response-1 (Egr-1) and specificity protein 1 (Sp1) were measured by in situ hybridization (ISH) and immunohistochemistry (IHC) technique. GT21-apsTFO, GT20-apsTFO, GT20-psTFO and FITC-labeled apsTFO, matching with the SSRE of TF gene promoter region, were designed, and intravenously injected into rats at 0.5 h before operation. TFO was detected 4 h after the operation, and the mRNA expression and protein synthesis of TF, Egr-1 and Sp1 were detected 6 h after the operation. RESULTS: There were much fluorescence in vascular tissue, especially in the nuclear of ECs 4.5 h after the injection of apsTFO. The mRNA expression and protein synthesis of TF reduced by 22% - 23% with injection of GT20-apsTFO 6.5 h after stenosis (P < 0.01) and by 10% - 11% with GT21-apsTFO at the same time (P < 0.05). The inhibition by GT20-apsTFO was stronger than that of the GT21-apsTFO (P < 0.05). The expression of TF was not inhibited by the GT20-psTFO (P > 0.05). The mRNA expression and protein synthesis of Egr-1 and Sp1 did not change in the rat treated with GT20-apsTFO, GT20-psTFO and GT21-apsTFO (P > 0.05). CONCLUSION: apsTFO could mero-inhibit the expression of TF gene but could not change the expression of Egr-1 and Sp1 protein.

Animals↗

PubMed2006

[Preparation and properties of medical calcium phosphate cement].

The preparation of tetracalcium phosphate (Ca4(PO4)2O, TTCP)was studied. Then calcium phosphate cement (CPC) was prepared. The setting time, pH value, compressive strength, X-ray diffraction (XRD) and scanning electron microscope (SEM) analysis of CPC were studied. The results show that TTCP containing small amount of CaO can be successfully attained heated at 1 500 degrees C for 6 h in vacuum condition. The initial setting time and final setting time of CPC is 4 min and 15 min, respectively. Its compressive strength is 20 MPa after 1-day immersion and 35 MPa after 7-day immersion. The pH value of the solution changes between 6.4 and 8.9. These properties can satisfy the clinical requirements of CPC. The final product of CPC is flake-like or needle-like hydroxyapatite (Ca5(P04)3OH, HA). The continuous network structure of HA appears in the microstructure, this leads to increase the strength of the material. This CPC can be used as bone substitute material.

Bone Cements↗

PubMed2006

Protein expression of human neuron-specific enolase and its antiserum preparation.

OBJECTIVE: To clone and express human neuron-specific enolase (HuNSE) protein and prepare NSE-specific antibody for prion disease diagnosis. METHODS: HuNSE gene was amplified by RT-PCR and subcloned into a HIS-tagged expression vector pQE30 after sequence verification. HIS-NSE fusion protein expression was obtained in E. coli M15 after IPTG induction followed by purification of the fusion protein by Ni-NTA affinity chromatography. Two male rabbits were immunized for 4 times with the purified protein, and the antiserum against NSE protein was collected and evaluated by enzyme-linked immunosorbent assay (ELISA), Western blotting and immunohistochemistry. RESULTS: SDS-PAGE assay yielded an approximately 22 kD HIS-NSE fusion protein. The prepared antiserum could recognize both recombinant NSE protein and native NSE protein extracted from the brain tissues of different mammalian species as shown by Western blotting and immunohistochemistry. CONCLUSION: High expression of HuNSE is obtained in E. coli and the prepared antiserum against HuNSE can be used potentially for diagnosis of prion-associated diseases and other nervous degeneration diseases.

Animals↗

PubMed2006

[Effects of Sini decoction on vascular stenosis after iliac artery balloon injury and oxidative stress in rabbits].

OBJECTIVE: To investigate the effect of Sini decoction (SND) in preventing vascular restenosis and protecting against oxidative stress after rabbit iliac artery balloon injury. METHODS: Twenty-four male New Zealand albino rabbits were equally randomized into control group, model group and SND group. Rabbits in the control group were fed with common forage, and those in the model and SND groups with high-fat diet. Two weeks later, the iliac arteries of the rabbits in the latter two groups were subjected to balloon injury. Four weeks after the operation, the rabbits were killed and the vascular structure was observed by scanning electron microscope and optical microscope, with the serum cholesterol level, superoxide dismutase (SOD) activity and malondialdehyde (MDA) level determined. RESULTS: Scanning electron microscopy showed that the endothelial cell lining in the iliac artery of the control and SND group remain regular, but the arteries in the model group presented with desquamated and exposure of the collagen fibril beneath the endothelium. Optical microscope revealed narrowed vascular lumen, thicken intima and numerous arteriosclerotic plaques in the model group in comparison with the control group, whereas the vascular lumen and intima thickness remained basically normal in SND group. The levels of total cholesterol, low-density lipoprotein cholesterol and triglyceride were decreased with high-density lipoprotein cholesterol levels increased in SND group, which was not observed in the model group. The serum SOD activity was higher in the control group than in the model and SND groups, but SND group had higher serum SOD activity than the model group. The serum MDA level was lower in the control group than in the other two groups, but SND group had lower MDA level than the model group. CONCLUSION: SND can alleviate intimal hyperplasia and vascular stenosis in injured rabbit iliac artery, possibly in relation to increased SOD activity and decreased lipid peroxidation as a result of SND treatment.

Angioplasty, Balloon, Coronary↗

PubMed2006

[The expression of enhanced green fluorescent protein gene on cultured human fetal retinal progenitor cells].

PURPOSE: To investigate the transfer efficiency and transient expression of plasmid vector coding enhanced green fluorescent protein (EGFP)gene pEGFP-N1 which was transferred into primary cultured human fetal retinal progenitor cells. To build up a tracking method for study of retinal progenitor cells transplantation. METHODS: pEGFP-N1 plasmid was amplified in E.coli, primary cultured human fetal retinal progenitor cells transferred with pEGFP-N1 by means of CaCl2. The transfer efficiency was evaluated by flow cytometry. Transient expression in vitro was observed by fluorescent microscope and laser scanning confocal microscope. RESULTS: The transfer efficiency of pEGFP-N1 into primary cultured human fetal retinal progenitor cells could maximumly reach to 32.45% during 48 hours. There was obvious expression of pEGFP-N1 in vitro at 48th hour after transferring. CONCLUSION: pEGFP-N1 is an ideal transient expression vector for primary cultured human fetal retinal progenitor cells in vitro. It is a useful tracer for transplantation of retinal progenitor cells.

Cells, Cultured↗

PubMed2006

[Expression and purification of recombinant human interleukin 4 in Escherichia coli].

Human interleukin 4 (IL-4) cDNA was optimized and synthesized according to E. coli preferred codon. A recombinant expression plasmid pET-30a (+)/rhIL-4 was constructed with the target cDNA inserted between Nde I and EcoR I sites, which can translate the mature IL-4 protein with an extra methionine residue at N-terminal. The expression vector was transformed into E. coli BL21 (DE3). The rhIL-4 protein was expressed in the inclusion body. By using the optimized fermentation conditions, the high expression level was achieved with the expression level as high as 35% of total protein obtained. A purification strategy has been designed which includes Q-Sepharose and SP-Sepharose ion-exchange chromatography and dialysis renaturation. The rhIL-4 was purified with the purity more than 98% and the yield of 40 mg per liter fermentation culture achieved. Western blot proved that the purified protein is IL-4. Amino acid sequencing revealed that N-terminal 16 residue sequence is identical to the theoretical sequence. Biological activity assay on TF-1 cells demonstrated that the rhIL-4 is active with an activity of 2.5 x 10(6) AU/mg. This study promises large scale production of rhIL-4.

Amino Acid Sequence↗

PubMed2006

[Optical-fiber Fourier transform spectrometer].

A novel Fourier transform spectrum analyzer based on a single mode fiber Mach-Zehnder interferometer is reported. An optical fiber Fourier transform spectrometer, with bulk optics components replaced by fiber optical components and with the moving mirror replaced by a piezoelectric element fiber stretcher was constructed. The output spectrum of a LD below threshold was measured. Experiment result agrees with that by using grating spectrum analyzer, showing the feasibility of the optic fiber Fourier transform spectrometer for practical spectrum measurement. Spectrum resolution -7 cm(-1) was obtained in our experiment. The resolution can be further improved by increasing the maximum optical path difference.

English Abstract↗

PubMed2006

[A comparison study for differentiation between human fetal retinal progenitor cells and brain neural stem cells in vitro].

OBJECTIVE: Investigating the potential of differentiation of human fetal retinal progenitor cells (hRPCs) and brain neural stem cells (hBNSCs) in vitro. METHODS: hRPCs and hBNSCs were isolated from human fetuses (8-12 weeks of gestation) and cultured in serum-free DMEM/F12 culture medium with N2 supplement, epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) or culture medium with 10% fetal bovine serum (FBS) but without EGF and bFGF. Immunocytochemical and immunofluorescence studies were conducted for identification of neural stem cells, retinal progenitors or the subtypes of neurons, astrocytes, retinal ganglion cells and rod photoreceptors with the specific antibodies for Nestin, Pax6, Map2, GFAP, Thy-1 and Rhodopsin, respectively. RESULTS: Both hRPCs and hBNSCs could proliferate and differentiate in DMEM/F12 + N2 with or without 10% FBS and expressed specific markers of immature neuroepithelial cells, retinal progenitors, mature neurons, astrocytes, retinal ganglion cells and rod photoreceptors. hBNSCs easily attached, spread out longer neurites and to form a network when cultured with serum contained medium. hRPCs were more difficult to attach and had only short dendrites. CONCLUSIONS: Both hRPCs and hBNSCs can differentiate into retinal specific cell types in vitro. The adherent, migration and differential capacity of hRPCs and hBNSCs are different when these cells are induced by the serum-contained culture medium.

Brain↗

PubMed2006

[The effect of ligustrazine on cells proliferation in cortex and striatum after focal cerebral ischemia in adult rats].

OBJECTIVE: To explore the effect of Ligustrazine on cells proliferation in cortex and striatum after focal cerebral ischemia in adult rats. METHODS: Focal cerebral ischemia was induced by left middle cerebral artery occlusion (MCAO) with suture method. Two hours later, injection of Ligustrazine (80 mg/kg, 1 time/d) was performed peritoneally. Four hours after the ischemia, 5-bromodeoxyuridine (BrdU) (50 mg/kg, 1 time/d) was injected peritoneally. At 7d, 14d and 21d after ischemia, BrdU-Labeled cells in the cortex and striatum were observed by immunohistochemical staining. RESULTS: In ischemia model group, at 7 day, BrdU-labeled cells were observed in the ipsilateral cortex and striatum. With the prolongation of ischemia, the number of BrdU-labeled cells increased, reached the peak at 21d. In Ligustrazine group, BrdU-labeded cells were observed with an intense distribution in ischemic penumbra of the cortex and striatum. With the prolongation of ischemia, the number of BrdU-labeled cells increased significantly at 14d, and reached the peak at 21d. The numbers of BrdU-labeled cells at 7d, 14d and 21d were more than those in ischemia model group respectively. CONCLUSION: Ligustrazine increase the proliferated cells in the cortex and striatum after focal cerebral ischemia in adult rats. The results suggest that it may be useful for promoting self-repair after ischemia.

Animals↗

PubMed2006

[Prevention and treatment of postoperative complications after skin soft tissue expansion for scar alopecia].

OBJECTIVE: To summarize the prevention and treatment of postoperative complications after the skin soft tissue expansion for scar alopecia. METHODS: From January 1995 to June 2005, 57 patients with scar alopecia were admitted to our department for treatment. Of the patients, 25 were males and 32 were females with their ages ranging from 5 to 55 years. The causes were burn in 33 patients, trauma in 14, alopecia after head surgery in 8, and other causes in 2. Their disease courses ranged from 6 months to 15 years. For treatment, 89 therapeutic expanders were utilized in 57 patients. The retrospective analysis on the complications and their prevention and treatment were performed. RESULTS: The follow-up for 3-12 months averaged 6 months revealed that 81 areas undergoing the expander insertion healed well and the hair grew well, too. Eight areas undergoing the expander insertions had complications, including expander exposure in 2 patients, infection in 2, hematoma in 1, expander rupture in 1, necrosis of the flap tip in I, and scar necrosis at the injection port in 1. The results also revealed that there was a significantly increased rate of complications in the patients aged 5-10 years and the patients older than 50 years (P<0. 05). The complication rate in the patients who received 2 expanders at one time was significantly higher than that in the patients who received only 1 expander (P<0. 05). However, there was no significant difference in the complication rate in the other kinds of patients. All the complications were effectively treated with a satisfactory therapeutic result. CONCLUSION: The skin soft tissue expansion for scar alopecia can effectively prevent and treat postoperative complications. If the complications are identified early and treated properly, the therapeutic results will be satisfactory.

Adolescent↗

PubMed2005

Synthesis of high-density grafted polymer layers with thickness and grafting density gradients.

A novel approach was developed for the synthesis of tethered polymer layers with thickness and grafting density gradients. Poly(glycidyl methacrylate) (PGMA) was employed as a primary anchoring layer to attach the polymer chains to the surface of a silicon wafer. A linear temperature gradient heated stage was used for the generation of a gradual variation in the thickness of the anchoring PGMA film along the substrate. The obtained gradient was translated into the polymerization initiator gradient via the reaction between the epoxy groups of PGMA and the carboxyl functionality of 2-bromo-2-methylpropionic acid (BPA). The attachment of BPA to the surface modified with the monolayer of PGMA was confirmed by X-ray photoelectron spectroscopy experiments. To complete the experimental procedures, surface-initiated atom transfer radical polymerization was performed to synthesize the grafted polymer layers with thickness and surface densities that were varied along the substrate. The grafting density of the samples created in this three-step process ranged from 0.75 +/- 0.05 to 1.5 +/- 0.25 chains/nm(2). It was estimated, from a comparison of the surface densities of the initiator and the attached polymer, that the efficiency of the initiation from the surface was on the order of 5-10% and was dependent upon the surface concentration of the initiator and the time of polymerization.

Journal Article↗

PubMed2005

Catalytic hydrodechlorination of 2,4-dichlorophenol over nanoscale Pd/Fe: reaction pathway and some experimental parameters.

Nanoscale Pd/Fe bimetallic particles were synthesized and used to hydrodechlorinate 2,4-dichlorophenol. 2,4-dichlorophenol was transformed to phenol with a small amount of 2-chlorophenol and 4-chlorophenol produced. The reaction pathway and reaction rate constants for each step have been determined. The effects of various Pd bulk loadings in the bi-metals, temperatures and pH conditions on the hydrodechlorination of 2,4-dichlorophenol were examined. The results showed that higher Pd bulk loadings, higher temperatures and weak acid conditions are beneficial to the catalytic dechlorination of 2,4-dichlorophenol.

Anthelmintics↗

PubMed2005

Neuroprotection against ischaemic brain injury by a GluR6-9c peptide containing the TAT protein transduction sequence.

It is well documented that N-methyl-D-aspartate and alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate receptors play a pivotal role in ischaemic brain injury. Recent studies have shown that kainate (KA) receptors are involved in neuronal cell death induced by seizure, which is mediated by the GluR6*PSD-95*MLK3 signalling module and subsequent c-Jun N-terminal kinase (JNK) activation. Here we investigate whether GluR6 mediated JNK activation is correlated with ischaemic brain injury. Our results show that cerebral ischaemia followed by reperfusion can enhance the assembly of the GluR6*PSD-95*MLK3 signalling module and JNK activation. As a result, activated JNK can not only phosphorylate the transcription factor c-Jun and up-regulate Fas L expression but can also phosphorylate 14-3-3 and promote Bax translocation to mitochondria, increase the release of cytochrome c and increase caspase-3 activation. These results indicate that GluR6 mediated JNK activation induced by ischaemia/reperfusion ultimately results in neuronal cell death via nuclear and non-nuclear pathways. Furthermore, the peptides we constructed, Tat-GluR6-9c, show a protective role against neuronal death induced by cerebral ischaemia/reperfusion through inhibiting the GluR6 mediated signal pathway. In summary, our results indicate that the KA receptor subunit GluR6 mediated JNK activation is involved in ischaemic brain injury and provides a new approach for stroke therapy.

Animals↗

PubMed2005

Inhibition of atherogenesis in LDLR knockout mice by systemic delivery of adeno-associated virus type 2-hIL-10.

Atherosclerosis is an inflammatory disease of the arteries. Interleukin-10 (IL-10) is known to be an anti-inflammatory cytokine which might be useful for counteracting the development of atherosclerosis. As long-term systemic cytokine delivery is prohibitively expensive, gene therapy might be a suitable approach. To test this idea, low-density lipoprotein receptor (LDLR) knockout mice were injected with recombinant adeno-associated virus type 2 (AAV)/interleukin-10 virus or AAV/granulocyte macrophage-colony stimulating factor (GM-CSF) virus and then put on a high-cholesterol diet. Upon harvesting the animals at 18 weeks, elevated blood lipids could be documented and AAV/IL-10 and AAV/GM-CSF DNA and mRNA could be found in various mouse organs. The mice receiving the AAV/IL-10 virus had significantly lower levels of atherogenesis (Sudan IV-staining and histology) than the untreated or the AAV/GM-CSF-treated animals, dropping from 53% to 17% (p < 0.05). The aortas of the AAV/IL-10-treated animals displayed higher IL-10 expression and lower CD68 and nitrotyrosine expression. These data are similar to those of Yoshioka et al. [Yoshioka, T, Okada, T, Maeda, Y, et al. Adeno-associatedvirus vector-mediated interleukin-10 gene transfer inhibits atherosclerosis in apolipoprotein E-deficient mice. Gene Ther 2004;11:1772-9] in which AAV/IL-10 was delivered into the tibial muscle of ApoE-deficient mice, instead of tail vein injection used here. These data indicate that systemic AAV/IL-10 gene delivery, with resulting inhibition of inflammation and oxidative stress, was able to limit atherogenesis, and suggest that this approach is worthy of further study.

Animals↗