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Biomedical subjects

Jian Liu

Publications and source records attributed to Jian Liu.

At least 163 records · Page 9Linked to original sources
PubMed2004

[Ultrasound microbubbles promote thrombolysis of rabbit femoral artery thrombus].

OBJECTIVE: To evaluate the efficacy of intravenous ultrasound microbubbles for thrombolysis of arterial thrombus without using thrombolytic drugs. METHODS: Twelve rabbit models of acute bilateral femoral artery thrombosis were established and 6 of them received transcutaneous ultrasound and intravenous albumin microbubble treatment for thrombosis on one side while only microbubble treatment for the other side. The other 6 rabbits received ultrasound treatment on one side but no treatment on the other to serve as the control group. RESULTS: None of the 6 arteries treated with microbubbles alone and only 2 arteries treated with ultrasound alone in the 6 control rabbits were recanalized. All the 6 femoral arteries treated with microbubbles together with ultrasound were recanalized (P=0.014), with significantly shorter patent time and smaller residual thrombus cross-sectional area than those of the arteries with only ultrasound treatment (P=0.004 and P=0.003, respectively). CONCLUSION: Treatment with intravenous microbubbles assisted by transcutaneous ultrasound effectively promotes arterial thrombolysis in vivo, and this technique can be of significance in clinical treatment of acute thrombotic occlusions.

Animals↗
PubMed2004

[Constructing the tumor cell vaccine based on homologous matrix metalloproteinase-2 and exploring its effects].

OBJECTIVE: To construct the tumor cell vaccine based on homologous matrix metalloproteinase-2 (MMP-2), and explore its anti-tumor effects. METHODS: The tumor cell vaccine was constructed by transfecting chicken MMP-2 to tumor cells. MTT colorimetric assay was used to evaluate the activation of the transfectants. Then we observed the formative tumor response in vivo and evaluated the effects of the tumour cell vaccine in immunized mice rechallenged with parental cells. RESULTS: Using RT-PCR, we picked out the cell strain with the highest expression level from the transfectants. The MTT colorimetric assay revealed that the transfectants increased the expression of the MMP-2 of tumor cells while they did not change the trend of tumor cells' growth. And in animal experiments the vaccine was preliminarily found to be effective for inhibiting the tumour growth and prolonging the survival time of animals. CONCLUSION: We have constructed the tumor cell vaccine based on homologous matrix metalloproteinase-2. The experiments demonstrated that breaking the immune tolerance of MMP-2 by means of active immunity should be a useful approach to cancer therapy.

Adenocarcinoma↗
PubMed2004

[Inhibition of malignant ascites with endostatin adenoviral vector].

OBJECTIVE: To evaluate the therapeutical effect of endostatin adenoviral vector on malignant ascites and compare it with the combined effect of ad-endostatin and DDP. METHODS: We transfected SKOV3 cells with ad-endostatin to inhibit human umbilical vein endothelial cells (HUVEC) proliferation. Then we administered ad-endostatin intraperitoneally in BALB/c mice to detect the serum endostatin expression and in the mice with malignant ascites to evaluate the therapeutic efficacy. RESULTS: Recombinant endostatin inhibited HUVEC proliferation. Endostatin was expressed in serum after intraperitoneal injection of ad-endostatin. The effects of endostatin on inhibition of the ascites accumulation and peritoneal capillary permeability, on demotion of VEGF protein level and microvascular density in tumor tissues, on reduction of the number of red cells and tumor cells counted in malignant ascites, and on prolongation of mice survival were significant in two different malignant ascites. Furthermore, the combination of ad-endostatin with DDP increased the therapeutic efficacy. CONCLUSION: These data suggested that endostatin gene therapy may represent a potential new treatment for malignant ascites, and the therapeutic efficacy can be enhanced by a combination of ad-endostatin with chemotherapy.

Adenoviridae↗
PubMed2004

[Effects of Radix Salviae Miltiorrhizae on the PMN-EC adhesion in vitro at the early stage of endotoxemia].

OBJECTIVE: To evaluate the effects of Radix Salviae Miltiorrhizae (RSM) on the PMN-EC adhesion in vitro at the early stage of endotoxemia, and to probe into the mechanism there in involved. METHODS: The rabbit endotoxemia model was made, and one group was treated with RSM injection (2 ml/kg) instantly and 24 h after the modeling of endotoxemia. PMN-EC adhesion rate, adhesion molecule (CD11a/CD18 and CD11b/CD18) and TNF-alpha level were measured instantly, 2 h, 4 h, 8 h, 16 h, 24 h and 48 h after endotoxemia modeling. RESULTS: It was found that after the modeling of endotoxemia, the levels of CD11a/CD18, CD11b/CD18 and PMN-EC adhesion rate instantly increased in the endotoxemia group and RSM group, they went up to the peak at 4 h in the endotoxemia group, and at 2 h, 4 h, 8 h, 16 h, 24 h and 48 h, they were markedly lower in the RSM group than in the endotoxemia group (P < 0.05). The TNF-alpha level in the endotoxemia group began to increase 2 h after the modeling and reached to the peak at 8 h, with its level still higher than normal at 48 h, while the RSM group had lower level of TNF-alpha at all time-points(P < 0.05). CONCLUSION: The data from this animal experiment indicate that Radix Salviae Miltiorrhizae can decrease PMN-EC adhesion rate and the levels of CD11a/CD18, CD11b/CD18 and TNF-alpha in case of endotoxemia so as to improve the microcirculation.

Animals↗
PubMed2004

[Effect of anti-infective reconstituted bone xenograft as primary bone grafting on repair of contaminated radius defect in canine].

OBJECTIVE: To investigate the effect of anti-infective reconstituted bone xenograft (ARBX) as primary grafting on repair of a segmental contaminated defect in canine radius. METHODS: The contaminated segmental defects of 1.5 cm were made in both radius of 8 canine and 1 ml of staphylococal suspension was injected into the defect region at a concentration of 5 x 10(6) CFU/ml. ARBX(experimental side) or RBX(control side) was implanted into the two sides of the defects respectively as primary grafting followed by internal fixation. The results were compared between the two grafting materials in repairing the contaminated segmental defect. RESULTS: In ARBX side, the defects were repaired completely in 5 cases and partially in 1 case, and there existed no osteomyelitis in all cases; while in RBX side, the defects were repaired partially in 1 case and were not repaired in 5 cases after 6 months of operation, and there existed osteomyelitis in all cases. CONCLUSION: Besides its strong osteoinductive and osteoconductive activity, ARBX is highly antibacterial and can be used as primary grafting in repairing contaminated segmental defects.

Animals↗
PubMed2004

[Study on extraction process of Radix Bupleuri].

The orthogonal design was used to optimize extraction process of Radix Bupleuri with content of total saponin and yield of the extract as markers. Factors that have been chosen were ethanol concentration, ethanol consumption, extraction times and extraction time. Each factor had three levels. The result showed that the optimum extraction condition was 80% ethanol, 4 times the amount of material, refluxing for 4 times, 60 minutes each time. The optimized process was stable and workable.

Analysis of Variance↗
PubMed2003

The interaction of the human GGA1 GAT domain with rabaptin-5 is mediated by residues on its three-helix bundle.

GGA proteins regulate clathrin-coated vesicle trafficking by interacting with multiple proteins during vesicle assembly. As part of this process, the GAT domain of GGA is known to interact with both ARF and Rabaptin-5. Particularly, the GAT domains of GGA1 and -2, but not of GGA3, specifically bind with a coiled-coil region of Rabaptin-5. Rabaptin-5 interacts with Rab5 and is an essential component of the fusion machinery for targeting endocytic vesicles to early endosomes. The recently determined crystal structure of the GGA1 GAT domain has provided insights into its interactions with partner proteins. Here, we describe mutagenesis studies on the GAT-Rabaptin-5 interaction. The results demonstrate that a hydrophobic surface patch on the C-terminal three-helix bundle motif of the GAT domain is directly involved in Rabaptin-5 binding. A GGA3-like mutation, N284S, in this Rabaptin-5 binding patch of GGA1 led to a reduced level of Rabaptin-5 binding. Furthermore, a reversed mutation, S293N, in GGA3 partially establishes Rabaptin-5 binding ability in its GAT domain. These results provide a structural explanation for the binding affinity difference among GGA proteins. The current results also suggest that the binding of GAT to Rabaptin-5 is independent of its interaction with ARF.

ADP-Ribosylation Factors↗
PubMed2003

Ion transport diagnostics in a microsecond pulsed Grimm-type glow discharge time-of-flight mass spectrometer.

A Grimm-type glow discharge ion source, operated in the microsecond pulsed mode, has been interfaced to a commercial time-of-flight mass spectrometer. Ion transport from the source to the mass spectrometer, an inherent limitation of a Grimm source and mass spectrometer combination, was evaluated. The primary discharge operating conditions found to influence transport efficiency were gas flow rate and source pressure. The configuration of the Grimm-type source also influenced ion transport, including use of a gas-directing sleeve device. The effect of transport efficiency was separated into two components: (1) total ion signal and (2) temporal resolution. The latter is an advantage afforded by use of a pulsed glow discharge source and time-of-flight spectrometer, which allows discrimination against interfering gaseous background ions by appropriate ion sampling time. Shown as an example is the identification of trace magnesium from potential background interference using an optimized source configuration based on this temporal resolution method.

Journal Article↗
PubMed2003

Solving the "world-to-chip" interface problem with a microfluidic matrix.

We report an effective solution to the macroscopic/microfluidic interface issue and demonstrate how microfluidics can achieve impressive economies of scale in reducing the complexity of pipetting operations. Using an N x N microfluidic matrix with N = 20, we performed N2 = 400 distinct PCR reactions with only 2N + 1 = 41 pipetting steps, compared with the 3N2 = 1200 steps required with conventional fluid handling. Each vertex of the matrix has a 3-nL reactor, and a single 2-microL aliquot of polymerase is amortized over all 400 independent reactions, thus dramatically reducing sample overhead and minimizing reagent consumption. Beyond PCR, the matrix chip provides a general method to perform chemical and biological experiments with precious reagents in a highly automated fashion.

Journal Article↗
PubMed2003

Estrogen affects BDNF expression following chronic constriction nerve injury.

To investigate the effect of estrogen on BDNF expression in neuropathic pain. Using chronic constriction injury model, we detected BDNF mRNA and protein level by reverse transcription polymerase chain reaction and enzyme-linked immunosorbent assay, respectively. A hot-plate test was used as a sign of neuropathic pain. The rats with higher estrogen level exhibited more sensitive to thermal stimuli and had a higher level of BDNF mRNA and protein expression. The results suggest that BDNF level can be elevated by estrogen and estrogen may potentiate the sensitivity to thermal stimuli by its effect on BDNF expression. Thus, this study improves our understanding of the role of estrogen in the nociceptive processing.

Animals↗
PubMed2003

Clonal vaccinia virus grown in cell culture as a new smallpox vaccine.

Although the smallpox virus was eradicated over 20 years ago, its potential release through bioterrorism has generated renewed interest in vaccination. To develop a modern smallpox vaccine, we have adapted vaccinia virus that was derived from the existing Dryvax vaccine for growth in a human diploid cell line. We characterized six cloned and one uncloned vaccine candidates. One clone, designated ACAM1000, was chosen for development based on its comparability to Dryvax when tested in mice, rabbits and monkeys for virulence and immunogenicity. By most measures, ACAM1000 was less virulent than Dryvax. We compared ACAM1000 and Dryvax in a randomized, double-blind human clinical study. The vaccines were equivalent in their ability to produce major cutaneous reactions ('takes') and to induce neutralizing antibody and cell-mediated immunity against vaccinia virus.

Animals↗
PubMed2003

Biosynthesis of 3-O-sulfated heparan sulfate: unique substrate specificity of heparan sulfate 3-O-sulfotransferase isoform 5.

Heparan sulfate 3-O-sulfotransferase transfers sulfate to the 3-OH position of a glucosamine to generate 3-O-sulfated heparan sulfate (HS), which is a rare component in HS from natural sources. We previously reported that 3-O- sulfotransferase isoform 5 (3-OST-5) generates both an antithrombin-binding site to exhibit anticoagulant activity and a binding site for herpes simplex virus 1 glycoprotein D to serve as an entry receptor for herpes simplex virus. In this study, we characterize the substrate specificity of 3-OST-5 using the purified enzyme. The enzyme was expressed in insect cells using the baculovirus expression approach and was purified by using heparin-Sepharose and 3',5'-ADP- agarose chromatographies. As expected, the purified enzyme generates both an antithrombin binding site and a glycoprotein D binding site. We isolated IdoUA-AnMan3S and IdoUA-AnMan3S6S from nitrous acid-degraded 3-OST-5-modified HS (pH 1.5), suggesting that 3-OST-5 enzyme sulfates the glucosamine residue that is linked to an iduronic acid residue at the nonreducing end. We also isolated a disaccharide with a structure of DeltaUA2S-GlcNS3S and a tetrasaccharide with a structure of DeltaUA2S-GlcNS-IdoUA2S-GlcNH23S6S from heparin lyases-digested 3-OST-5-modified HS. Our results suggest that 3-OST-5 enzyme sulfates both N-sulfated glucosamine and N-unsubstituted glucosamine residues. Taken together, the results indicate that 3-OST-5 has broader substrate specificity than those of 3-OST-1 and 3-OST-3. The unique substrate specificity of 3-OST-5 serves as an additional tool to study the mechanism for the biosynthesis of biologically active HS.

Animals↗
PubMed2003

Angiotensin II modulates nitric oxide-induced cardiac fibroblast apoptosis by activation of AKT/PKB.

Previously we found that interleukin-1beta (IL-1beta)-activated inducible nitric oxide (NO) synthase (iNOS) expression and that NO production can trigger cardiac fibroblast (CFb) apoptosis. Here, we provide evidence that angiotensin II (ANG II) significantly attenuated IL-1beta-induced iNOS expression and NO production in CFbs while simultaneously decreasing apoptotic frequency. The anti-apoptotic effect of ANG II was abolished when cells were pretreated with the specific ANG II type 1 receptor (AT1) antagonist losartan, but not by the AT2 antagonist DP-123319. Furthermore, ANG II also protected CFbs from apoptosis induced by the NO donor diethylenetriamine NONOate and this effect was associated with phosphorylation of Akt/protein kinase B at Ser473. The effects of ANG II on Akt phosphorylation and NO donor-induced CFb apoptosis were abrogated when cells were preincubated with the specific phosphatidylinositol 3-kinase inhibitors wortmannin or LY-294002. These data demonstrate that ANG II protection of CFbs from IL-1beta-induced apoptosis is associated with downregulation of iNOS expression and requires an intact phosphatidylinositol 3-kinase-Akt survival signal pathway. The findings suggest that ANG II and NO may play a role in regulating the cell population size by their countervailing influences on cardiac fibroblast viability.

Angiotensin II↗
PubMed2003

Deletion mapping using quantitative real-time PCR identifies two distinct 3p21.3 regions affected in most cervical carcinomas.

We report chromosome 3p deletion mapping of 32 cervical carcinoma (CC) biopsies using 26 microsatellite markers located in frequently deleted 3p regions to detect loss of heterozygosity and homozygous loss. In addition, two STS markers (NLJ-003 and NL3-001) located in the 3p21.3 telomeric (3p21.3T) and 3p21.3 centromeric (3p21.3C) regions, respectively, were used for quantitative real-time PCR as TaqMan probes. We show that quantitative real-time PCR is reliable and sensitive and allows discriminating between 0, 1 and 2 marker copies per human genome. For the first time, frequent (five of 32 cases, i.e. 15.6%) homozygous deletions were demonstrated in CCs in both 3p21.3T and 3p21.3C regions. The smallest region homozygously deleted in 3p21.3C was located between D3S1568 (CACNA2D2 gene) and D3S4604 (SEMA3F gene) and contains 17 genes previously defined as lung cancer candidate Tumor suppressor genes (TSG(s)). The smallest region homozygously deleted in 3p21.3T was flanked by D3S1298 and NL1-024 (D3S4285), excluding DLEC1 and MYD88 as candidate TSGs involved in cervical carcinogenesis. Overall, this region contains five potential candidates, namely GOLGA4, APRG1, ITGA9, HYA22 and VILL, which need to be analysed. The data showed that aberrations of either NLJ-003 or NL3-001 were detected in 29 cases (90.6%) and most likely have a synergistic effect (P<0.01). The study also demonstrated that aberrations in 3p21.3 were complex and in addition to deletions, may involve gene amplification as well. The results strongly suggest that 3p21.3T and 3p21.3C regions harbor genes involved in the origin and/or development of CCs and imply that those genes might be multiple TSG(s).

Carcinoma↗
PubMed2003

Expression of functional protease-activated receptor 1 in human prostate cancer cell lines.

Functional protease-activated receptors (PAR) are expressed by a variety of malignant cells. In the present study, RT-PCR assays demonstrated the expression of the thrombin receptor PAR-1 mRNA in human prostate cancer cell lines DU 145, LnCAP, and SV40-immortalized human prostate epithelial cell line PNT1A. In contrast, the additional thrombin receptors PAR-3 and PAR-4 were not detected. PAR-1 protein localized to the cellular surface was detected by flow cytometry in all three cell lines. To demonstrate the functional importance of the PAR-1, the effects of different concentrations of thrombin on cell proliferation kinetics were assessed. The treatment of growth-arrested cells with varying concentrations of thrombin demonstrated dose- and time-dependent effects. At low concentration (<0.5 U/ml), thrombin induced proliferation of all prostate-derived cell lines. Thrombin at higher concentration (1.0 U/ml) initially stimulated PNT1A and LnCAP cells to proliferate (time of thrombin application 24 h and 48 h) followed by inhibited growth when assessed after 72 h of incubation. In contrast, 1.0 U/ml thrombin caused earlier inhibition of DU 145 proliferation starting at 48 h of incubation. Our results suggest that PAR-1 mediates the proliferation-modulating effects of thrombin on prostate cancer cells.

Cell Division↗
PubMed2003

[Experimental study of anti-infective reconstructed bone xenograft].

OBJECTIVE: To develop a new type bone graft material that can be used as primary graft in contaminated even infected bone defect. METHODS: Anti-infective reconstructed bone xenograft (ARBX) was developed by combining reconstructed bone xenograft (RBX) with gentamycin and gelatin. One piece of ARBX was implanted in the muscle pouch in right thighs of 32 mice. The implanted ARBX and surrounding soft tissues were taken out from the mice at different time point to make into homogenate and the concentration of released gentamycin in the supernatant and the diameter of the bacterial inhibition ring of each specimen were tested. One piece of ARBX was implanted into the muscle pouch at the right thigh of 16 mice and one piece of RBX was implanted into the muscle pouch at the right thigh of another 16 mice. Fourteen days after the grafts and surrounding tissues were taken out to be examined histologically or made into homogenate to test the alkaline phophatase (ALP) activity. Bone defect was made in the bilateral radii and then Staphylococcus aureus was injected and debridement was conducted. 10 pieces of ARBX were implanted into the bone defect at the left radius and 10 pieces of RBX were implanted into the bone defect at the right radius. The defect was then fixed and the wound was sutured. Gentamycin was injected for 1 week. Six months later X ray examination was conducted to the radius, then the radius was taken and half of specimens were examined histologically and half of them was made into homogenate to examine the amount of Staphylococcus aureus. Defect was made in the right tibia of 25 rabbits and Staphylococcus aureus injected therein. Then the rabbits were divided into 5 groups of 5 individuals: group 1 (3 pieces of ARBX were implanted), group 2 (3 pieces of RBX were implanted and gentamycin was used locally), group 4 (3 pieces of RBX were implanted and gentamycin was injected intramuscularly), and group 5 (control group, without born grafting). Eight weeks after, radiological, histological, and bacteriological methods were used to observe the recovery of bone defect and amount of Staphylococcus aureus. RESULTS: Gentamycin was released slowly from the ARBX and the effective bacterium-inhibiting concentration lasted 30 days. There was no significant difference in osteoinductive activity and related ALP activity between the mice implanted with ARBX and RBX. The bone defect of the dogs implanted with ARBX recovered better than that of the dogs implanted with RBX; osteomyelitis was found in the specimens from the bone defect implanted with RBX and not in the specimens implanted with ARBX, and the positive rate of Staphylococcus aureus was lower in the specimens implanted with ARBX than in the specimens implanted with RBX. 8 weeks after the implantation the Norden score of osteomyelitis was the lowest in the rabbits of group 1 (P < 0.01). The bone defect recovered better in the rabbits of groups 1 and 2. The number of Staphylococcus aureus in the bone defect in rabbits of group 1 was significantly smaller than that in the rabbits of group 2 (P < 0.05), and was very significantly smaller then in the rabbits of the other 3 groups (P < 0.01). CONCLUSION: ARBX has strong oeteoinductive and anti-infective abilities. It can be used in primary bone grafting to treat contaminated even infected bone defect.

Animals↗
PubMed2003

[Anatomical study and three dimensional image characteristic analysis of basicranial artery and its clinical significance].

OBJECTIVE: To observe and measure the inside diameter of basicranial arteries, the angulation of main arteries, the three dimensional image characteristic of internal carotid arteries and the anatomical variation of Willis circle. METHODS: The arteries of 30 formalin-fixed adult heads were injected with latex after which the caliber and characteristic of cerebral arteries were observed and measured. The three dimensional image characteristic of internal carotid arteries and its branches were measured using 3D-DSA. RESULTS: (1) Main artery caliber: origin of internal carotid artery (Left 5.12 +/- 1.48 mm; Right 5.11 +/- 1.42 mm); origin of middle cerebral artery (Left 2.93 +/- 1.44 mm; Right 2.92 +/- 1.46 mm); origin of anterior cerebral artery (Left 2.63 +/- 1.33 mm; Right 2.61 +/- 1.32 mm); origin of vertebral artery (Left 4.37 +/- 1.21 mm; Right 3.22 +/- 1.64 mm); origin of basilar artery (4.45 +/- 1.28 mm); origin of posterior cerebral artery (Left 2.62 +/- 1.36 mm; Right 2.61 +/- 1.22 mm). (2) The angulation of main arteries: C1, 2 of ICA and C4, 5 of ICA (Left 32 +/- 22 degrees; Right 36 +/- 28 degrees ); ICA and ACA (Left 43 +/- 26 degrees; Right 46 +/- 28 degrees). (3) The results show that anatomical and three dimensional image characteristic of internal carotid arteries have no difference (P > 0.05). (4) The anatomical variation of Willis circle: Type O (56.7%); Type A (16.7%); Type P (20.0%); Type AP (6.7%). CONCLUSIONS: It is helpful to measure the inside diameter of basicranial arteries for the selection of various catheter in interventional neuroradiology, to observe the angulation of main arteries and the three dimensional image characteristic of internal carotid arteries for the moulding of various catheter in endovascular therapy and to master the anatomical variation of Willis circle for decreasing complications of endovascular treatment and judging prognosis of cerebrovascular diseases.

Adult↗