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Biomedical subjects

Jie Liu

Publications and source records attributed to Jie Liu.

At least 127 records · Page 7Linked to original sources
PubMed2006

Modeling and phantom studies of ultrasonic wall shear rate measurements using coded pulse excitation.

Wall shear rate (WSR) is the derivative of blood velocity with respect to vessel radius at the endothelial cell (EC) surface. The product of WSR and blood viscosity is the wall shear stress (WSS) that has been identified as an important factor for atherosclerosis development. High echo signal-to-noise ratio (eSNR) and high spatial resolution are crucial for minimizing the errors in WSR estimates. By transmitting coded pulses with time-bandwidth product greater than one, high eSNR from weak blood scatter can be achieved without increasing instantaneous power or sacrificing spatial resolution. This paper summarizes a series of measurements in a straight tube (5-mm diameter), constant velocity flow phantom using a 10 MHz transducer (60% bandwidth, f/1.5) imaged with a 72 degrees Doppler angle, 125 MHz sampling frequency and 1 kHz pulse repetition frequency. Measurements were made using a frequency-modulated (FM) code, phase-modulated (PM) codes, and uncoded broadband and narrow band pulse transmissions. Both simulation and experimental results show that coded-pulse excitation increases accuracy and precision in WSR estimation for laminar flow over a broad range of peak velocity values when compared to standard pulsing techniques in noise-limited conditions (eSNR < 30 dB). The code sequence and its length are selected to balance range lobe suppression with eSNR and echo coherence enhancements to minimize WSR errors. In our study, the combination of an eight bit Optimal coded pulse with a Wiener compression filter yielded the highest WSR estimation performance.

Animals↗
PubMed2006

[Construction of eukaryotic expression vector of siRNA specific for MAD2 and its effect on the growth of gastric cell line SGC7901].

AIM: To construct the RNA interference eukaryotic expression vector specific for human MAD2 gene and to observe its effect on the growth of gastric cancer cell line SGC7901. METHODS: The expression vectors of pSilencer3.1/MAD2-siRNA1 and pSilencer3.1/MAD2-siRNA2 were constructed by gene recombination and then were stably transfected into the gastric carcinoma cell line SGC7901 by liposome mediation. The expression of MAD2 on the levels of protein and mRNA was detected by Western blot and RT-PCR, and the monoclone with the highest inhibition efficiency was selected. The growth of the transfected cells was assessed by MTT. And the cells treated with 1.0 mg/L vincristine (VCR) for 24 h were analyzed by FCM for cell cycle. RESULTS: Sequence-specific siRNAs targeting MAD2 significantly down regulated the expression of MAD2 in SGC7901 cells. In MAD2-siRNA transfected cells, the rate of cell growth increased markedly and cell cycle couldn't be arrested in M phase induced by VCR, while the cells transfected with the mock vector could. CONCLUSION: Down regulation of MAD2 expression of SGC7901 bv sequence-specific siRNA could accelerate the cell growth and impair the mitosis arrest of SGC7901 induced by VCR.

Animals↗
PubMed2006

[Insulin prevents injury and enhances survival of rat hepatocytes via its anti-inflammatory effects].

AIM: To investigate whether insulin exerts protective effects against hepatocytes injury indirectly induced by LPS and if so, the mechanism involved. METHODS: Kupffer cells and hepatocytes were isolated from male Sprague-Dawley rats by pronasecollagenase perfusion and cultured. Kupffer cells were stimulated by lipopolysaccharide (LPS) or LPS+insulin for 4 h, the supernatant of different groups were collected to detect TNF-alpha and IL-10 by ELISA and to stimulate the primary cultured rat hepatocytes with or without anti-TNF-alpha antibody. After the hepatocytes were stimulated for 12 h, cell survival rate and injury indexes were detected. RESULTS: (1) The supernatant of LPS-activated Kupffer cells caused significant hepatocytes injury. Treatment with insulin produced a potent protective effect as evidenced by decreased ALT and AST levels (P<0.01, n=8) and improved hepatocytes survival rate (P<0.01, n=8). (2) Compared with the LPS group, insulin significantly decreased TNF-alpha secretion (P<0.01, n=8) and increased IL-10 secretion (P<0.05, n=8) from Kupffer cell stimulated by LPS. (3) Incubating hepatocytes with anti-TNF-alpha antibody attenuated hepatocytes injury induced by the supernatant of LPS-activated Kupffer cells. But treatment with anti-TNF-alpha antibody and insulin did not exert additive effect compared with treatment with insulin alone. CONCLUSION: Insulin has protective effects on rat hepatocytes injury indirectly induced by LPS, which is associated with suppression of the pro-inflammatory cytokine TNF-alpha and increment of the anti-inflammatory cytokine IL-10 both from Kupffer cells.

Animals↗
PubMed2006

[Regulation of the expression of interleukin-4 and interleukin-5 by the signal pathway of PKC-NF-kappaB in T lymphocyte of allergic rhinitis].

OBJECTIVE: To explore the role of nuclear factor-kappaB (NF-kappaB) in the signal pathway of protein kinase C (PKC) regulating the expression of interleukin-4 (IL-4) and interleukin-5 (IL-5) by T lymphocyte in allergic rhinitis. METHOD: Twenty-four allergic rhinitis patients and 24 normal control persons participated in the study. T lymphocytes were isolated and purified from blood of each person and divided into 3 groups: cells of 1st group were control group(Normal control and AR control),cells of 2nd group were stimulated with phorbol 12-myristate 13-acetate (Normal PMA and AR PMA),cells of 3rd group were stimulated with PMA and pyrrolidine dithiocarbamate (Normal PMA/PDTC and AR PMA/PDTC). The expression of NF-kappaB were observed by immunocytochemical staining, IL-4 and IL-5 protein in supernatants were measured by ELISA. RESULT: The percentage of cells of active NF-kappaB, IL-4 and IL-5 protein in supernatants of allergic rhinitis T lymphocyte stimulated with PMA were significantly higher than those of allergic rhinitis T lymphocyte stimulated without PMA ( P < 0.01) and with PMA and PDTC ( P < 0.01); than those of normal control T lymphocyte stimulated with PMA ( P < 0.01), with PMA and PDTC ( P < 0.01) and without PMA. The percentage of cells of active NF-kappaB, IL-4 and IL-5 protein in supernatants of allergic rhinitis T lymphocyte stimulated with PMA and PDTC were significantly lower than those of allergic rhinitis T lymphocyte stimulated with PMA (P < 0.01); but significantly higher than those of allergic rhinitis T lymphocyte stimulated without PMA and those of normal T lymphocyte stimulated. There were good positive correlation between the percentage of cells of active NF-kappaB and IL-4 and IL-5 protein in supernatants (r = 0.88,0.85, P < 0.01, respectively). CONCLUSION: The active PKC of allergic rhinitis T lymphocyte increasing the expression of IL-4 and IL-5 may be mediated by activating NF-kappaB, the activation of PKC-NF-kappaB signal pathway of T lymphocyte NF-kappaB may play an important role in the pathogenesis of allergic rhinitis.

Adult↗
PubMed2006

[Effect of polymorphism of human intestinal fatty acid binding protein gene on the therapeutic efficacy of fenofibrate].

OBJECTIVE: To explore the effect of polymorphism in codon Ala54Thr of human intestinal fatty acid-binding protein gene (IFABP) on the therapeutic efficacy of fenofibrate. METHODS: Totally 147 patients with hyperlipidemia [72 men mean age: (56.2 +/- 8.63) years; 75 women mean age: (58.4 +/- 9.12) years] were enrolled. IFABP genotypes were detected by polymerase chain reaction, Hha I digestion, and sequencing. Four weeks before and after treatment, the levels of fasting serum total cholesterol (TC), triglyceride (TG), high density lipoprotein-cholesterol (HDL-C), low density lipoprotein-cholesterol (LDL-C), apolipoprotein A I (apoA I) and apolipoprotein B (apoB) were detected with biochemical techniques. RESULTS: The frequency of IFABP genotype was 0.47 for A/A, 0.37 for A/T, and 0.16 for T/T, and the allelic frequency was 0.65 for A and 0.35 for T. No significant different was found in lipid levels in every genotype before treatment (P > 0.05). After 4 weeks of treatment, the levels of TC, TG, LDL-C, and apoB significantly decreased (P < 00.01), and the levels of HDH-C and apoA I significantly increased (P < 0.01). The total therapeutic efficacy on A54A and A54T were 97% and 95%, respectively. In the patients with T54T genotype after treatment, no significant difference in lipids levels was found except TG (P < 0.05), and the total efficacy was only 38%. The total therapeutic efficacies of fenofibrate on A54A and A54T were higher than those of T54T, and there was significant different between A54A and T54T (P < 0.01). CONCLUSION: The polymorphism of human IFABP gene in hyperlipidemia is related with the therapeutic efficacy of fenofibrate, and the T54T IFABP genotype may have strong negative effect on such efficacy.

Aged↗
PubMed2006

[Serum fibrosis markers in diagnosing liver fibrosis].

OBJECTIVE: To evaluate the clinical value of serum fibrosis markers hyaluronic acid (HA), type IV collagen (CIV), type III procollagen N peptide (PIIIP) and laminin (LN) in the diagnosis of liver fibrosis. METHODS: Detection of the serum levels of these markers including HA, CIV, PIIIP, LN was carried out in 50 patients with chronic hepatitis B and 18 healthy persons. Liver biopsy was performed in all patients. The relationship between the markers and liver fibrosis stage was analyzed and the diagnostic value of the markers in liver fibrosis stage evaluated with receiver operating curve. RESULTS: The correlation between serum HA, CIV, PIIIP and histologically assessed grade of inflammatory activity was weak (r = 0.430, 0.382 and 0.300, respectively, P < 0.05). The correlation between serum HA, CIV and histologically assessed stage of liver fibrosis were moderate (r = 0.614, 0.708, respectively, P < 0.05). The increase in serum HA, CIV was correlated with the progression of liver fibrosis. Based on receiver operating curve, the value of using serum HA to differentiate patients with early cirrhosis (S4) from those without cirrhosis (S0-S3) was greater than that of serum CIV, PIIIP and LN (the areas under the curves = 0.967 vs 0.932, 0.659, 0.403), while the ability of serum CIV to predict liver fibrosis (S1-S4) was superior to that of serum HA, PIIIP and LN (areas under the curves = 0.853 vs 0.680, 0.536, 0.487). Serum LN was found to show limited changes in different pathologic grade and stage. The combined detection of HA and CIV has higher specificity than that of a single marker. CONCLUSIONS: Serum fibrosis markers can be helpful in diagnosis of liver fibrosis even in its early stage, but can not discriminate accurately the stage of fibrosis as accurately as the histological assessment. The combination of fibrosis markers is more valuable than single marker. New fibrosis markers and combination of noninvasive markers are the future trend in liver fibrosis research.

Adult↗
PubMed2006

[Human peripheral blood CD56+ natural killer cell subsets and their phenotypic and biological properties].

OBJECTIVE: To characterize the phenotypic and biological properties of CD56(+) natural killer cells from human peripheral blood mononuclear cells (PBMCs). METHODS: Surface markers and intracellular cytotoxic molecules were stained with multi-color-labeled monoclonal antibodies and analyzed at the single cell level the relation between NK subsets and biological characteristics by flow cytometry. RESULTS: NK cells in PBMCs could be divided into two major populations, CD56(bright) and CD56(dim), based upon the expression of CD56 molecules. Both CD56(bright) and CD56(dim) expressed CD95 (Fas) with CD95(bright) and CD95(dim) subsets. CD56(dim) subsets had higher percentage of CD8, granzyme B and perforin expression compared to those of CD56(bright) subsets. In CD56(bright) and CD56(dim) subpopulations, CD95(bright) and CD8(+) subsets had higher percentage of granzyme B and perforin expression. CONCLUSION: CD56(+) NK cells in PBMCs are composed of distinct subpopulations, CD56(dim) and CD56(dim) CD8(+) NK subsets have higher percentage of granzyme B and perforin and may play an important role in the killing of target cells.

CD56 Antigen↗
PubMed2006

[Determination and analysis of trace element manganese and amino acids content in aloe tea].

The content of trace element manganese in aloe tea was determined by atomic absorption spectrophotometry. The contents of 17 kinds of amino acids in aloe tea were determined with amino acids instrumentation. The results showed that there are comparatively rich manganese and amino acids in aloe tea. The content of manganese in red tea is more than in green tea, and the dissolving ratio is more than 50% in boiled water, and first dissolving ratio is more than second dissolving ratio, which is more than third dissolving ratio. There are 7 kinds of amino acids essential to human body, among which are comparatively high aspartic acid, glutamic acid and leucine in aloe tea. It's outstanding characteristic is comparatively high content of manganese in aloe health tea. It has provided useful data for probing into the relationship between trace elements and amino acids in aloe health tea and health care function.

Aloe↗
PubMed2006

[Study on chemical constituents of volatile oil and trace elements from fruits of Clausena lansium].

OBJECTIVE: To study and determine the chemical constituents of the volatile oil and the trace elements in the fruits of the Clausena lansium. METHOD: The essential oils were extracted by supercritical fluid extraction (SFE) and separated on capillary columns with HP6890GC-5973MS. The components were quantitatively determined with normalization method, and were identified with GC-MS. And the trace elements were determined by ICP-MS and ICP-AES. RESULT: 36 Components constituting 95% of the total essential oil were separated and identified, and 11 trace elements were identified. CONCLUSION: 18 Compounds were found from the fruit of C. lansium for the first time.

Carbon Dioxide↗
PubMed2006

[kgp genotypes of Porphyromonas gingivalis in subgingival plaque in puberty gingivitis].

OBJECTIVE: To assess the prevalence of specific kgp genotypes in puberty gingivitis and investigate their possible association with disease severity. METHODS: Subgingival plaque samples were collected from 72 pubertal children aged from 14 to 17 years, which were divided into two groups, gingivitis group and healthy (control) group. Clinical parameters were recorded beforehand. PCR technique was used to amplify the region encoding the catalytic domain of gingipain K (KGP). The PCR products were digested with restriction enzymes Mse I. RESULTS: The kgp-A genotype was digested in fragments of 102 bp, 288 bp and 402 bp, and kgp-B genotype was unrestricted with 792 bp. Virulent strain P. gingivalis W83 was manifested by kgp-A genotype while a virulent strain P. gingivalis ATCC 33277 was manifested by kgp-B genotype. All P. gingivalis positive subjects were subgingivally colonized by only one kgp genotype. The prevalence of kgp-A genotype in puberty gingivitis group and gingival healthy group was 79.0% and 22.2% respectively. The distribution differences of genotypes between the two groups were statistically different (P = 0.028). There was no statistically significant difference in the clinical parameters between pubertal subjects harboring P. gingivalis of kgp-A genotype and kgp-B genotype (P > 0.05). CONCLUSIONS: Most subjects with puberty gingivitis were harbored by the same kgp genotype as that of virulent strain P. gingivalis W83. It may be necessary to continue to monitor individuals who are positive for P. gingivalis of kgp-A genotype since their risk of developing periodontal diseases may be increased in the future.

Adolescent↗
PubMed2006

[Effect of ligustrazine, synthetic borneol on lasting time of ciliary movement].

OBJECTIVE: To study the using of the method in vitro and in vivo of lasting time of ciliary movement in ligustrazine, synthetic borneol. METHODS: (1) Method in vitro-The lasting time of ciliary movement was observed with forty-fold optical microscope after dropping liquid medicine on exteacorporeal frog palate mucosa. Then mucosa was cleared. It was observed whether the ciliary movement was recovered and the lasting time was recorded from recovering to stopping once again. (2) Method in vivo-Liquid medicine or normal saline was dropped on frog palate mucosa by contacting thirty minutes. Then mucosa was cleared. The lasting time of ciliary movement was observed with forty-fold optical microscope by separating palate mucosa. RESULTS: Relatively percentage of lasting time of ciliary movement of ligustrazine in vitro and in vivo was 9.8%, 87.3%; The relatively percentage of synthetic borneol in vitro and in vivo was 9.3%, 89.5%. CONCLUSION: The method in vitro and in vivo of lasting time of ciliary movement can be the one of the selecting ways of Chinese drug's toxicity of nasal mucosa, and it have virtues and defects respectively. Ligustrazine, synthetic borneol have significantly toxical effect on exteacorporeal lasting time of ciliary movement.

Administration, Intranasal↗
PubMed2006

[Application of the free vascularized lateral upper arm flap in intraoral reconstruction following ablative tumour surgery].

OBJECTIVE: To evaluate the application of the lateral arm free flap (LAFF) in the reconstruction for intraoral defects. METHODS: Intraoral reconstruction was performed using the LAFF for 10 patients with oral squamous cell carcinoma of the tongue (n = 3), cheek (n = 4), gingiva (n = 1) and oropharynx (n = 2). There were 8 men and 2 women (mean age, 52 years). RESULTS: Nine LAFF healed uneventfully. One flap was lost on the second postoperative day due to venous insufficiency. The donor defect was closed primarily In all patients. There were no significant complications at the donor site. CONCLUSIONS: Because of the thin and pliable nature, the lateral upper arm flap can be recommended as a choice for repair of moderate-sized defects of the oral maxillofacial area.

Adult↗
PubMed2006

[Study on amino acids from the fruit of Clausena lansium].

OBJECTIVE: To investigate the amino acids from the fruit of Clausenae lansium. METHODS: To determine the content of hydrolyzed and free amino acids from fresh fruit and dried fruit of Clausenae lansium by HPLC, 10 mmol/L Na2HPO4 (PB) was used as mobile phase (A) and PB-methanol-acetic acid (50:35:15) was used as mobile phase (B) on a Hypersil ODS column. RESULTS: 16 kinds of amino acids were assayed, 10 of all was necessary or half-necessary amino acids. The total content of free and hydrolyzed amino was 4.8 mg/g and 15.0 mg/g in fresh fruit; 4.8 mg/g and 15.0 mg/g in dried fruit. CONCLUSION: There are abundant amino acids in the fruit of Clausenae lansium.

Amino Acids↗
PubMed2005

Transplacental arsenic plus postnatal 12-O-teradecanoyl phorbol-13-acetate exposures associated with hepatocarcinogenesis induce similar aberrant gene expression patterns in male and female mouse liver.

Our prior work shows that in utero arsenic exposure alone is a complete transplacental carcinogen, producing hepatocellular carcinoma in adult male offspring but not in females. In a follow-up study to potentially promote arsenic-initiated tumors, mice were exposed to arsenic (85 ppm) from gestation day 8 to 18 and then exposed to 12-O-teradecanoyl phorbol-13-acetate (TPA), a well-known tumor promoter after weaning. The dermal application of TPA (2 mug/0.1 ml acetone, twice/week for 21 weeks) after transplacental arsenic did not further increase arsenic-induced liver tumor formation in adult males but significantly increased liver tumor formation in adult females. Thus, for comparison, liver tumors and normal liver samples taken from adult male and female mice at necropsy were analyzed for aberrant gene/protein expression by microarray, real-time RT-PCR and Western blot analysis. Arsenic/TPA treatment resulted in increased expression of alpha-fetoprotein, k-ras, c-myc, estrogen receptor-alpha, cyclin D1, cdk2na, plasminogen activator inhibitor-1, cytokeratin-8, cytokeratin-18, glutathione S-transferases and insulin-like growth factor binding proteins in liver and liver tumors from both male and female mice. Arsenic/TPA also decreased the expression of BRCA1, betaine-homocysteine methyltransferase, CYP7B1, CYP2F2 and insulin-like growth factor-1 in normal and cancerous livers. Alterations in these gene products were associated with arsenic/TPA-induced liver tumors, regardless of sex. Thus, transplacental arsenic plus postnatal TPA exposure induced similar aberrant gene expression patterns in male and female mouse liver, which are persistent and potentially important to the mechanism of arsenic initiation of hepatocarcinogenesis.

Administration, Topical↗
PubMed2005

Podophyllotoxin-loaded solid lipid nanoparticles for epidermal targeting.

The purpose of this study was to evaluate solid lipid nanoparticles as the topical carrier for epidermal targeting of podophyllotoxin (POD). The high pressure homogenization was employed to prepare drug-loaded solid lipid nanoparticles. The POD-loaded SLN stabilized by 0.5% poloxamer 188 and 1.5% soybean lecithin (P-SLN) and 2% polysorbate 80 (T-SLN) was characterized by photon correlation spectroscopy (PCS). P-SLN showed an average diameter of 73.4 nm and a zeta potential of -48.36 mV. The imaging of AFM indicated that the P-SLN had a spherical shape. DSC and X-ray diffraction analysis showed that POD was dispersed in SLN in an amorphous state. The in vitro permeation study showed that P-SLN increased the accumulative amount of POD in porcine skin 3.48 times over 0.15% tincture. But T-SLN with a diameter of 123.1 nm and a zeta potential of -17.4 mV did not show a high accumulative amount of POD when compared with P-SLN, though both P-SLN and T-SLN could avoid the systemic uptake of POD. Because of the fluorescence property of POD, fluorescence microscopy imaging was employed to visualize the penetration of POD into skin from SLN. The penetration of POD from P-SLN seemed to follow two pathways along the stratum corneum and hair follicle route. The imaging revealed that P-SLN had a strong localization of POD within epidermis. The penetration of P-SLN with low particle size into stratum corneum along the skin surface 'furrow' and the consequent controlled release of POD might lead to the epidermal targeting. P-SLN provides a good epidermal targeting effect and may be a promising carrier for topical delivery of POD.

Animals↗
PubMed2005

Creation of cadmium sulfide nanostructures using AFM dip-pen nanolithography.

A dip-pen nanolithography (DPN) process capable of depositing nanoscaled structures of semiconducting CdS materials was developed by careful control of the reaction speed between the precursors. The new development expanded the scope of the powerful DPN process and provided more insight in the deposition mechanism. Features ranging from several hundreds of nanometers to sub-50 nanometers were generated and characterized. The effects of the surface property of the substrate, the relative humidity, the translating rate, and the temperature were systematically investigated. X-ray photoelectron spectroscopy (XPS) was used to verify the chemical composition of the patterns. In principle, this simple and convenient method should be applicable to deposit various metal sulfides on suitable substrates.

Journal Article↗
PubMed2005

Bright infrared emission from electrically induced excitons in carbon nanotubes.

We used the high local electric fields at the junction between the suspended and supported parts of a single carbon nanotube molecule to produce unusually bright infrared emission under unipolar operation. Carriers were accelerated by band-bending at the suspension interface, and they created excitons that radiatively recombined. This excitation mechanism is approximately 1000 times more efficient than recombination of independently injected electrons and holes, and it results from weak electron-phonon scattering and strong electron-hole binding caused by one-dimensional confinement. The ensuing high excitation density allows us to observe emission from higher excited states not seen by photoexcitation. The excitation mechanism of these states was analyzed.

Journal Article↗