Biomedical subjects

H Liu

Publications and source records attributed to H Liu.

At least 469 records · Page 26Linked to original sources

PubMed2000

[Construction and expression of recombinant adeno-associated HIV -1 virus].

OBJECTIVE: Plasmid of AAV vector with HIV-1 gag and gp 120 were constructed respectively. METHODS: The recombinant AAV-HIV gag and gp120 viruses were obtained by co transfection of AAV-HIV plasmid and Adenovirus 5 in 293 cells. RESULTS: The recombinant AAV-HIV virus expressed well and the titer of the recombinant viruses were between 10(4)-10(5). CONCLUSIONS: The recombinant AAV-HIV virus can be used to infect the target cells for detection of cellular immunity and for vaccine studies.

Adenoviruses, Human↗

PubMed2000

[The immortalized cell lines induced by human papillomavirus type 16 (HPVS 16) YY1 binding-site mutants have some characteristics of transformed cells].

OBJECTIVE: To study the biological characteristics of the immortalized cell lines of human keratinocytes from foreskin induced by human papillomavirus type 16 (HPV 16) YY1 binding-site mutants. METHODS: The cellular extracts of immortalized cell lines were prepared and the cellular endogenous p53 proteins were determined with Western blot. The cellular telomerase activities were analyzed with TRAP. The immortalized cells were incubated in a soft agarose medium containing 10% FCS and the anchorage-independent growth abilities of the tested cell lines were evaluated. RESULTS: Western blot showed that the endogenous p53 protein in all 4 tested clones were undetectable. The telomerases were clearly identified within the 4 tested cell lines, and showed an increasing activity along with the passages of the cells. All the clones were unable to grow in the soft-agarose medium during the earlier passages, but three of them showed anchorage-independent-growth at the passages of 30-35. CONCLUSIONS: The immortalized cell lines induced by the HPV 16 YY1 binding-site mutants have active telomerase activity and ability of anchorage-independent growth.

Agar↗

PubMed2000

Triptolide: a potent inhibitor of NF-kappa B in T-lymphocytes.

AIM: To study the effect of triptolide on the activity of nuclear factor-kappa B (NF-kappa B) and gene expression of I kappa B alpha, a major inhibitor of NF-kappa B, in human Jurkat T cell line. METHODS: Jurkat cells treated with or without PMA/PHA were incubated with varied doses of triptolide for different time periods. The activity of NF-kappa B in Jurkat cells was measured with electrophoretic mobility shift assays (EMSA), and the mRNA expression of I kappa B alpha in Jurkat cells was detected by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: PMA/PHA treatment was found to induce NF-kappa B activation rapidly. Triptolide treatment decreased the activity of NF-kappa B in both PMA/PHA treated and untreated Jurkat cells. This effect of triptolide was in a dose-dependent manner and was more obvious in cells treated with PMA/PHA. The mRNA expression of I kappa B alpha were upregulated by triptolide, while this effect was more potent in cells without PMA/PHA treatment. CONCLUSION: Triptolide is a potent inhibitor of NF-kappa B activation in T lymphocyte and this effect is partly due to the upregulation of I kappa B alpha mRNA expression.

DNA-Binding Proteins↗

PubMed2000

[Therapeutic effect of blood activating polypeptide on the treatment of chronic severe viral hepatitis].

OBJECTIVE: To study the therapeutic effect of blood activating polypeptide on chronic severe viral hepatitis (CSH) and the method used. METHODS: The treated group included 50 CSH patients (male 82, female 8, age 39 +/- 9). Based on routine treatments, they were intravenously injected with 15 ml blood activating polypeptide dissolved in 250 ml of 10% glucose, qd x 4 wks. The control group contained 50 CSH patients (male 3, female 7, age 38+/-12). They were only treated with routine treatments for liver protection, jaundice regression, health maintenance, anti-infection and diuresis. RESULTS: The SB and ALT in treated patients decreased obviously (P < 0.01) after treatment, the prominent efficacy was 52%, the total efficacy was 86%, all were superior to the control group. CONCLUSIONS: Blood activating polypeptide is safe, reliable and effective in the treatment of CSH.

Adult↗

PubMed2000

[Effect of mixing seed with fulvic acid on spring wheat yield and its water use efficiency].

Four treatments were installed to study the effect of seed mixed with fulvic acid on sring wheat yield and water use efficiency: CK(without any treatment of fulvic acid); FA(seeds were mixed with fulvic acid before sowing), WM(pre-sowing irrigation of 30 mm plus clear plastic film mulch), and WMFA(pre-sowing irrigation of 30 mm plus plastic film mulch, and seeds were mixed with fulvic acid before sowing). The plastic film mulches in WM and WMFA treatments were removed after sowing for 62 days. Compared to treatment CK, the spring wheat in FA treatment grew more roots and absorbed more water from soil, and increased the spike weight and grain weight per spike and harvest index, which resulted in a higher yield and higher water use efficiency. There was no differenece in water consumption between treatments WM and WMFA, but in treatment WMFA, more dry matter was distributed in shoots, and hence yield and water use efficiency were improved significantly. The yields for the four treatments CK, FA, WM, WMFA were 917.7, 1275.1, 1269.4, 1737.1 kg.hm-2, respectively; and the water use efficiencies were 6.58, 7.85, 6.20, 9.05 kg.hm-2.mm-1, respectively.

Benzopyrans↗

PubMed2000

[Continuous cropping obstacle and rhizospheric microecology. III. Soil phenolic acids and their biological effect].

The contents of phenolic acids in the extracts of soil and roots of continuously cropped for five years and normally cropped soybean in Heilongjiang province and their biological effects were studied with HPLC method. The result showed that the contents of p-hydroxy benzoic acid, vanillic acid(extracted by 1 mol.L-1 NaOH) in continuous cropping soil were significant higher than that in normal cropping soil, and the content of vanillin had no significant difference in these soils. The contents of p-hydroxybenzoic acid, vanillic acid, vanillin, ferulic acids, and coumarin of aqueous extracts of soyhean roots were higher in continuous cropping than in normal cropping soil. The activity of polyphenol oxidase in continuous cropping soil was higher than in normal cropping soil. Under conditions of water culture and adding exogenous p-hydroxybenzoic acid, the aqueous extract of soybean roots inhibited the growth of soybean seedlings. After a week of exogenous phenolic acids addition, the residual rates of p-hydroxybenzoic acid, vanillic acid, vanillin, benzoic acid, ferulic acids, and coumarin were 10.4%, 15.3%, 4.1%, 2.3%, 5.2%, 17.5%, respectively. There was a very significant exponential relationship between the addition amount of exogenous phenolic acids and the fungi population in soil.

Agriculture↗

PubMed2000

Relationship between expression of type III collagen and phenotype of vascular smooth muscle cells in neointimal of stented coronary artery.

OBJECTIVE: To investigate the secretive features of type III collagen in restenosis of the stented coronary artery and the relationship between the expression of type III. collagen and vascular smooth muscle cells (VSMCs). METHODS: An animal model of restenosis was established by implanting oversized tantalum stents into the coronary arteries in 26 dogs. At the 7th, 14th and 28th days after implantation, the stented coronaries were harvested. Transmission electronic microscopy and immunohistochemistry were employed to investigate the features of type III collagen secretion and VSMCs' phenotype. The expression of type III collagen was quantified and compared for the three stages. RESULTS: Migration and proliferation of VSMCs were the main features at the 7th day after injury. At the 14th day, proliferation of VSMCs reached the peak while much more secretion of collagen was noticeable. VSMCs began to transform from the synthetic phenotype to the contractile phenotype at the 28th day, when a great quantity of collagen was also secreted. The quantity of secreted type III collagen was greater at the 14th and 28th day than that at the 7th day (P < 0.05). The stain density of type III collagen was positively correlated to neointimal thickness at both of 14th and 28th day. CONCLUSION: The pathological bases of restenosis are variant in different period of restenosis formation. Type III collagen may play an important role in the late stage of restenosis after coronary stenting.

Animals↗

PubMed2000

High frequency loss of heterozygosity in the region of the DBH locus in bladder cancer.

OBJECTIVE: To determine the location of a putative tumor suppressor gene (TSG), and evaluate the frequency loss of heterozygosity (LOH) of the long arm of chromosome 9 (9q) in bladder cancer. METHODS: We analyzed 25 patients with bladder cancer for LOH of 9q using 25 high-density microsatellite markers. RESULTS: Twenty-three samples (92%) showed LOH at least at one locus on 9q. We identified that the commonly deleted region were at 9q12-q21, 9q22, and 9q34. The rate of LOH was 44.0%, 22.7%, 22.7%, 16.0%, 12.0% on DBH, D9S15, D9S1815, D9S1831, D9S176 locus, respectively, and was not significantly related with grades and stages of tumor. CONCLUSION: These data suggest that alteration of a TSG at DBH of 9q may play an important role in the development of bladder cancer.

Chromosomes, Human, Pair 9↗

PubMed2000

[Regulation of the expression and function of glucose transporter-1 by TGF-beta 1 and high glucose in mesangial cells].

OBJECTIVE: To study the effects of high glucose and transforming growth factor-beta 1 (TGF-beta 1) on the expression and function of glucose transporter-1 (GLUT1) in mouse mesangial cells. METHODS: Cultured mouse mesangial cells were used. The expression of GLUT1 mRNA was detected by Northern Blot; glucose uptake and its kinetics were determined with a 2-Deoxy-[3H]-D-glucose uptake assay. RESULTS: Mesangial cells exposed to enriched glucose medium (20 mmol/L) for 72 hours demonstrated a decrease in both GLUT1 mRNA and Vmax for uptake of the glucose analog, 2-deoxy-D-glucose (2DOG), as compared to mesangial cells cultured in physiologic glucose concentrations (5.5 mmol/L). In contrast, hypertonic mannitol had no effect on GLUT1 mRNA levels. TGF-beta 1 treatment for 10 hours stimulated 2DOG uptake, both in 5.5 mmol/L and 20 mmol/L glucose medium, by approximately 4.28-fold in a dose-dependent manner (2 ng/ml maximum). Kinetic analysis of 2DOG uptake revealed an increase in Vmax and a decrease in Km in the presence of TGF-beta 1. TGF-beta 1 also up-regulated the expression of GLUT1 mRNA in mesangial cells. The addition of anti-TGF-beta neutralizing antibody (30 micrograms/ml) in mesangial cells cultured in enriched glucose medium (20 mmol/L) led to a 40% decrease in 2DOG uptake. CONCLUSIONS: The expression of GLUT1 can be suppressed by exposure of mesangial cells to high glucose medium, which may serve as a protective mechanism against possible adverse effects of excessive glucose flux into cells. TGF-beta 1 stimulates glucose uptake by enhancing the expression and function of GLUT1 in mesangial cells. This effect is independent of the glucose milieu in the cultured medium.

Animals↗

PubMed2000

Sequence variations of the hypervariable region of hepatitis C virus and their clinical significance.

OBJECTIVE: To understand the clinical significance of sequence variations in the hypervariable region (HVR) of hepatitis C virus during infection. METHODS: Eight patients with acute hepatitis C and 20 patients with chronic hepatitis C were followed up for two years. Blood samples were taken at intervals of six months for analysis of HCV-HVR sequences by reverse transcription-polymerase chain reaction (RT-PCR) and direct sequencing methods. RESULTS: HCV-HVR sequences of the 28 patients changed in various degrees. 92% of these nucleotide substitutions led to changes of corresponding aminoacid sequences. Only 8% of changed nucleotide were synonymous substitutions. Of 27 amino acids variation of amino acid ranged from 1 to 20 (mean 8, 30%). The most common nucleotide substitution (62%) occurred in the first position of codon, 31% in the second and the rest in the third. HVR variation rate was 0.89 x 10(-1) per genome site per year in acute hepatitis C, compared with 2.31 x 10(-1) per genome site per year in chronic hepatitis C (P < 0.05), but had no relation to HCV subtype. Variation of HVR in the flare up type (ALT > 150 mu/L) was much more than that in the quiescent type (ALT < 100 mu/L). CONCLUSION: Our results suggested that sequence variation of HVR during HCV chronic infection seems to be an adaptive response to HCV to evade the host immune pressure and might play a major role in the establishment of persistent infection as well as in the flare-up of hepatitis.

Acute Disease↗

PubMed2000

[Pathologic diagnosis of usual interstitial pneumonia].

OBJECTIVE: To discuss pathologic differential diagnosis between UIP and the other types of IPF. METHOD: The slides (routine and histochemical stain) of 4 autopsy cases of UIP were reviewed. RESULTS: The most significant characteristic of UIP is that the interstial changes show temporal heterogeneity and variable distribution. The earlier stage of UIP shows an interstitial infiltrate of chronic inflammation cells and the progressive stage appears significant interstitial fibrosis. The honeycomb change and muscular cirrhosis are the characteristics of the end stage. CONCLUSION: For clinical purpose, the distinction of UIP and the other types of IPF is of great significance because of marked differences in the prognosis and therapy.

Adult↗

PubMed2000

[A retrospective study of 3 cases of nonspecific interstitial pneumonia].

OBJECTIVE: To discuss the clinical features of nonspecific interstitial pneumonia. METHOD: Review of three cases of pathologically proved NSIP with the clinical, radiological, physical and bronchoscopic presentation. RESULTS: Three cases, one male and two females, aged from 49 to 59, presented with a duration of symptoms on diagnosis of 3 to 7 months. Cough, worsening dyspnea and inspiratory crackles were presented in all three cases and intermittent low grade fever in two but none has digital clubbing. There was a history of organic dust exposure in one case and in another case primary Sjögren's syndrome was diagnosed. Patchy ground-glass attenuation with thickening of bronchovascular markings were the main findings in high resolusion computed tomography (HRCT) of all three cases. Small areas of consolidation in two cases and traction bronchiectasis in one were found while there was no honeycombing. Increased bronchoalveolar lavage fluid (BALF) cell recovery and percentage of lymphocytes were found in all cases. The BALF CD4/CD8 ratio was measured in two cases and was markedly decreased in both cases. CONCLUSION: NSIP has some clinical features that are different from UIP and may provide clues to diagnosis.

Diagnosis, Differential↗

PubMed2000

[Effect of recombinant human bone morphogenetic protein-2 on the expression of osteopontin in human periodontal ligament cells].

OBJECTIVE: To investigate the effects of growth factor rhBMP-2 on the expression of osteopontin in periodontal ligament cells(PDLC). METHODS: In culture model of human PDLC, in situ hybridization method was used to detect the expression of osteopontin in human PDLC. RESULTS: The PDLC showed negative reaction to express osteopontin, while those PDLC stimulated by rhBMP-2 showed osteopontin mRNA positive reaction in plasm. CONCLUSION: rhBMP-2 can induce the expression of osteopontin in PDLC. rhBMP-2 may be an effective growth factor in stimulating PDLC differentiation to osteoblast and promote periodontal regeneration.

Bone Morphogenetic Protein 2↗

PubMed2000

[Effects of the occlusal splint on stress distribution of the mandible with temporomandibular joint disorders].

OBJECTIVE: To investigate the biomechanical mechanism of occlusal splint therapy of temporomandibular joint disorders (TMD). METHODS: The changes of stress distribution on the mandible with TMD before and after occlusal splint therapy were simulated and analyzed by three-dimensional finite element method. RESULTS: Occlusal splint influenced the character of stress distribution on the mandible. It might distinctly decrease maximum and minimum principal stresses on each region of the mandible with TMD, among which the stress on condylar surface of ill side was reduced more significantly, and the stress distribution of bilateral condyles was close to equality and balance. Meanwhile, the stress symmetry on every position of the mandible was improved slightly. CONCLUSIONS: Occlusal splint can alleviate even eliminate the injury to the temporomandibular joint, and make unbalance of joint inner environment adjusted and restored by improving the stress distribution. This is primarily thought to be one of the main biomechanical mechanism of occlusal splint treatment.

Biomechanical Phenomena↗

PubMed2000

[The construction of three-dimensional finite element model of human maxillary complex].

OBJECTIVE: To develop a method to construct three dimensional finite element (3-D FE) model which may express biomechanic dynamic state characters of normal maxillary complex. METHODS: SCT image reconstruction technique, digital image transfer and transcription and 3-D FEM were used in combination with self programming and ANSYS soft ware. RESULTS: A 3-D FE model of normal maxillary complex is constructed. The elements and nodes of the model are 2,602 and 4,595. CONCLUSION: The method to develop a model of maxillary complex adopting SCT 3-D image reconstruction technique, image transfer and transcription, and 3D FEM are feasible and effective.

Computer Simulation↗

PubMed2000

[The expression of glial cell derived neurotrophic factor and its receptor GDNFR-alpha and GDNFR-beta mRNA in spinal cord, brainstem and frontal cortex during morphine withdrawal in rats].

OBJECTIVE: To investigate the expression of glial cell derived neurotrophic factor (GDNF) and its receptor GDNFR-alpha (GFRalpha-1) and GDNFR-beta (Ret) genes and the effects of muscarinic receptor antagonists, NMDA receptor antagonist, inhibitor of nitric oxide synthase on the expression of these genes in the spinal cord, brainstem and frontal cortex during morphine withdrawal, and to observe the effects of GDNF antisense oligoneucleotide (i.c.v) on the morphine withdrawal symptoms in rats. METHODS: The levels of GDNF, GDNFR-alpha and GDNFR-beta mRNA were assayed by reverse transcription polymerase chain reaction (RT-PCR) with the beta-actin mRNA as an internal control. RESULTS: The GDNF mRNA levels were increased, and GDNFR-alpha and GDNFR-beta mRNA levels was slightly increased in the spinal cord and brainstem during morphine dependence. These genes were decreased at 1 h, increased at 2 h after administration of naloxone in morphine dependent rats. While the GDNF, GDNFR-alpha and GDNFR-beta levels in the frontal cortex were increased significantly at 1, 2 and 4 h after the injection of naloxone during morphine withdrawal. The pre-treatment with L-N-nitric arginine methylester (10 mg/kg), the expressions of GDNF and GDNFR-beta in the spinal cord, both GDNFR-alpha and GDNFR-beta in the frontal cortex were decreased. The expressions of both GDNF and GDNFR-alpha in the frontal cortex were decreased by treatment with MK801 (0.5 mg/kg), and the expressions of GDNF in both the stem and cortex, and GDNFR-beta in the brainstem decreased by treatment with the methyl-scopolamine (0.5 mg/kg). The beta-actin mRNA levels were not different in each group. Moreover, the morphine withdrawal symptoms were attenuated by intracerebroven tricular injection of GDNF antisense oligoneucleotide in 6 hour and 24 hour before naloxone administration in morphine dependent rats. CONCLUSION: The results not only provide direct evidence that the expressions of GDNF and its receptors mRNA in glial cells play an important role in mediating the process of morphine dependence and may be account for the long-term neuro-adaptation associated with morphine dependence, but also suggest that muscarinic receptor, NMDA receptor and nitric oxide pathways may be involved in the expression of GDNF and GDNF receptor genes during morphine withdrawal.

Animals↗

PubMed2000

[Effects of autogenous periodontal ligament cell transplantation on periodontal tissue regeneration in dogs].

OBJECTIVE: To evaluate the effect of autogenous periodontal ligament cell (PDL) transplantation in periodontal tissue regeneration. METHODS: PDL cells derived from the same dog were cultured with alpha-MEM. 1 x 10(5) cells of first passage were allowed to attach to the collagen membrane for 24 hours. The membrane-cells were transplanted into periodontal defect in the same dog. Then the defects were covered with e-PTFE membranes. The defects covered only with e-PTFE were the controls. Eighteen teeth of 6 dogs for each group were included. The dogs were sacrificed after 6 weeks. RESULTS: The results showed that new bone formation (4.00 +/- 0.13) mm in test group was significantly higher than that of in control group (3.09 +/- 0.28) mm, P < 0.05. The new cementum formation in test group was better than control group (P < 0.05). CONCLUSION: The results suggested that PDL cell transplantation with guided tissue regeneration technique could enhance periodontal tissue regeneration in dogs.

Animals↗

PubMed2000

[T1, T2 squamous or adenocarcinoma of the lung:characteristics of lymph node metastasis and its clinical significance].

OBJECTIVES: To investigate the frequency, distribution and features of lymph node metastasis in T(1)/T(2) squamous or adenocarcinoma of the lung, and to provide evidence for extensive dissection of lymph nodes. METHODS: 254 patients with T(1)/T(2) squamous or adenocarcinoma of the lung underwent R2 surgery plus extensive dissection of hilar, interlobular and mediastinal lymph nodes according to the grouping system proposed by Naruke. RESULTS: 1 685 groups of lymph nodes were dissected. The metastatic rates of N(1) and N(2) was 20.0% and 10.2% respectively. Significant difference existed between T(1) and T(2) tumors (P < 0.01). No N(2) metastasis was found in T(1) squamous cell carcinoma. N(2) metastatic rates were 22.0% in squamous cell carcinoma and 40.9% in adenocarcinoma (P < 0.01). 64.3% of squamous carcinoma spread to only one group of N(2) nodes, and over 3 groups of lymph nodes were positive in 46.2% of adenocarcinoma. Saltatory metastasis accounted for 57.5% of N(2) metastasis. 13.6% of N(2)-positive tumors in upper lobes metastasized to the lower mediastinum, whereas 51.6% of N(2)-positive cancers in the lower lobes spread to the upper mediastinum. CONCLUSIONS: The frequency of lymph nodes metastasis increases with the growth of tumors. Metastasis in adenocarcinoma occurs more frequently than in squamous carcinoma. Tumor at any site can metastasize to the distant mediastinum. Except for T(1) squamous cancer, radical surgery can be achieved only by extensive dissection of ipsilateral intrapulmonary and mediastinal lymph nodes.

Adenocarcinoma↗