Biomedical subjects

Yong Liu

Publications and source records attributed to Yong Liu.

At least 109 records · Page 6Linked to original sources

PubMed2005

Bioavailability and antioxidant effect of epigallocatechin gallate administered in purified form versus as green tea extract in healthy individuals.

Tea polyphenols have strong in vitro antioxidant activity. Due to their limited bioavailability, however, their contribution to in vivo antioxidant activity may depend on the form of administration. A human intervention study was performed to evaluate the bioavailability and antioxidant capacity of (-)-epigallocatechin-3-gallate (EGCG) administered as a single large dose in the form of either purified EGCG or as green tea extract (Polyphenon E). Plasma concentrations of tea polyphenols were determined by high-performance liquid chromatography (HPLC) analysis combined with coulometric array electrochemical detection (ECD). We found no differences in plasma EGCG concentrations and trolox equivalents determined by the trolox equivalent antioxidant capacity assay after administration of either form of EGCG. However, we found that the plasma antioxidant activity was significantly affected by changes in the plasma urate concentration, which may have interfered with the effect of tea polyphenols on the antioxidant activity. In addition, lymphocyte 8-hydroxydeoxyguanosine to deoxyguanosine (8-OHdG/10(6)dG) ratios were determined by HPLC with ECD. The 8-OHdG/10(6)dG ratios did not change significantly during the 24 h following both EGCG interventions but correlated significantly within individuals determined during the two interventions separated by 1 week. In summary, changes in plasma uric acid due to dietary intake were significantly correlated to the plasma antioxidant activity and exerted a stronger influence on the plasma antioxidant activity compared with the EGCG intervention. In future studies of dietary effects on the plasma antioxidant capacity, changes in plasma uric acid will need to be closely monitored.

8-Hydroxy-2'-Deoxyguanosine↗

PubMed2005

Use and specificity of breast cancer antigen/milk protein BA46 for generating anti-self-cytotoxic T lymphocytes by recombinant adeno-associated virus-based gene loading of dendritic cells.

Antigen-targeted immunotherapy is an emerging treatment for breast cancer. However, useful breast cancer antigens are only found in a subset of cancer patients. BA46, also known as lactadherin, is a membrane-associated glycoprotein that is expressed in most breast cancer cells but not in general hematopoietic cell populations. Moreover, it is much more difficult to generate CTLs against self-antigens. We wished to determine if the use of recombinant adeno-associated virus (rAAV) type 2 vectors for gene-loading of dendritic cells (DCs) could generate rapid, effective cytotoxic T lymphocytes (CTLs) against BA46. We were able to demonstrate that AAV/BA46/Neo-loading of DCs resulted in: (1) BA46 expression in DCs, (2) chromosomal integration of the AAV/BA46/Neo vector within DCs, (3) strong, rapid BA46-specific, MHC class I-restricted CTLs in only 1 week, (4) T-cell populations with significant interferon-gamma (IFN-gamma) expression but low IL-4 expression, (5) high CD80 and CD86 expression in DCs, and (6) high CD8:CD4 and CD8:CD56 T cell ratios. These data suggest that rAAV-loading of DCs may be useful for immunotherapeutic protocols against self-antigens in addition to viral antigens and that the BA46 antigen is potentially appropriate for cell-mediated immunotherapeutic protocols addressing ductal breast cancer.

Antibodies↗

PubMed2005

Dopamine D1 receptor interaction with arrestin3 in neostriatal neurons.

Dopamine D1 receptor interactions with arrestins have been characterized using heterologously expressed D1 receptor and arrestins. The purpose of this study was to investigate the interaction of the endogenous D1 receptor with endogenous arrestin2 and 3 in neostriatal neurons. Endogenous arrestin2 and 3 in striatal homogenates bound to the C-terminus of the D1 receptor in a glutathione-S-transferase (GST) pulldown assay, with arrestin3 binding more strongly. The D1 C-terminus and, to a lesser extent, the third cytoplasmic loop also bound purified arrestin2 and 3. In neostriatal neurons, 2, 5, and 20 min agonist treatment increased the colocalization of the D1 receptor and arrestin3 immunoreactivity without altering the colocalization of the D1 receptor and arrestin2. Further, agonist treatment for 5 and 20 min caused translocation of arrestin3, but not arrestin2, to the membrane. The binding of arrestin3, but not arrestin2, to the D1 receptor was increased as assessed by coimmunoprecipitation after agonist treatment for 5 and 20 min. Agonist treatment of neurons induced D1 receptor internalization (35-45%) that was maximal within 2-5 min, a time-course similar to that of the increase in colocalization of the D1 receptor with arrestin3. These data indicate that the D1 receptor preferentially interacts with arrestin3 in neostriatal neurons.

Animals↗

PubMed2005

Metamorphopsia after successful retinal detachment surgery: an optical coherence tomography study.

PURPOSE: To investigate the findings in optical coherence tomography (OCT) in eyes with metamorphopsia after scleral buckling surgery for macula-off retinal detachment. METHODS: A total of 46 patients (46 eyes) with macula-off retinal detachment were prospectively studied 2 months after successful scleral buckling surgery. Patients were examined with the Amsler grid, fundus biomicroscopy and OCT. RESULTS: At the 2 month follow-up, 31/46 (67%) patients had metamorphopsia; 24/31 (77%) of these patients had an abnormal macular structure on OCT and 7/31 (23%) showed a normal macula. However, of the 15 patients in the non-metamorphopsia group, 4/15 (27%) had an abnormal macula and 11/15 (73%) had a normal macula (p = 0.0015). The most common finding on OCT was neurosensory retinal detachment. CONCLUSIONS: Metamorphopsia after scleral buckling surgery in macula-off detachment is more common in patients in whom abnormal macular structure is seen on the OCT scan compared to those showing a normal macular structure. Neurosensory retinal detachment is the most common pathology in these patients.

Adolescent↗

PubMed2005

A dammarane glycoside derived from ginsenoside Rb3.

A dammarane glycoside, designated compound Mx (C-Mx), was isolated from the hydrolysate of 20(S)-protopanaxadiol type ginsenosides containing G-Rb(3) from Panax notoginseng leaves with crude snailase. Its chemical structure was elucidated to be 20-O-beta-D-xylopyranosyl(1-->6)-beta-D-glucopyranosyl-20(S)-protopanaxadiol on the basis of spectral analysis. Its cytotoxicity against breast cancer cell line MCF-7 and effects on the sensitivity to doxocubicin of doxocubicin-resistant MCF-7 cells were also investigated. The new compound showed moderate cytotoxicity and partial reversal of doxocubicin resistance.

Anti-Bacterial Agents↗

PubMed2005

Studying the HPV life cycle in 3A trophoblasts and resulting pathophysiology.

Human papillomavirus (HPV) productive infection has been long considered to be restricted to the squamous epithelium. However, we have demonstrated that both HPV type 16 (HPV-16) and type 31b (HPV-31b) productively replicate in a trophoblast cell line, 3A. Trophoblasts are an important cell type, as these are the cells of the placenta that directly contact maternal tissues. There are a number of studies that suggest that HPV infection may be found commonly in placental material and might be linked with spontaneous abortions. This chapter describes the preparation and transfection of HPV genomes into 3A cells, suggests ways to analyze viral replication and transcription, and describes how to assay the effect of HPV infection on the ability of the trophoblasts to bind endometrial cells.

Base Sequence↗

PubMed2005

Analysis of adeno-associated virus and HPV interaction.

It is slowly becoming accepted that adeno-associated virus (AAV) is another significant factor involved in cervical carcinogenesis. However, unlike human papillomavirus (HPV), which is positively associated with cervical cancer, AAV is negatively associated with this cancer. This negative association appears to be through a direct and complex bi-directional interaction between AAV and HPV. Essentially all assays used for studying HPV can be used for studying the AAV-HPV interaction. This is because both viruses are productive in the same tissue, the stratified squamous epithelium (skin). Their relationship can be studied on the level of the complete virus and their complete life cycle using the organotypic epithelial raft culture system, which generates a stratified squamous epithelium. Their relationship can be studied in various other tissue-culture models measuring oncogenic potential. Their interaction can also be studied on the component level, as both protein-protein and protein-DNA interactions are known. Their relationship has even been studied using transgenic animals. The AAV-HPV relationship can be broken down into two halves--AAV-encoded products, which affect HPV biology, and HPV-encoded products, which affect AAV biology. To date, the former are much better studied than the latter. The rep gene and its largest product, Rep78, are responsible for most of AAV's effects upon HPV. This chapter largely focuses on AAV's effect on the HPV life cycle.

Animals↗

PubMed2005

Simultaneous removal of nitrate and heavy metals by iron metal.

Great attention should be paid now to simultaneously removing common pollutants, especially inorganic pollutants such as nitrate and heavy metals, as individual removal has been investigated extensively. Removing common pollutants simultaneously by iron metal is a very effective alternative method. Near neutral pH, heavy metals, such as copper and nickel, can be removed rapidly by iron metal, while nitrate removal very much slower than that of copper and nickel, and copper can accelerate nitrate removal when both are removed simultaneously. Even a little amount of copper can enhance nitrate removal efficiently. Different mechanisms of these contaminants removal by iron metal were also discussed.

Copper↗

PubMed2005

Remediation of Cr(VI) in solution using vitamin C.

The effectiveness of vitamin C in treating Cr(VI)-contaminated water is being evaluated. Cr(VI) is an identified pollutant of some soils and groundwater. Vitamin C, an important biological reductant in humans and animals, can be used to transform Cr(VI) to essentially nontoxic Cr(III). The removal efficiency was 89% when the mass concentration of vitamin C was 80 mg/L in 60 min, and nearly 100% Cr(VI) was removed when the mass concentration was 100 mg/L. Our data demonstrated that the removal efficiency was affected by vitamin C concentration, the reaction temperature and the dissolved oxygen concentration. The reaction mechanism of Cr(VI) by vitamin C was presented. Our study opens the way to use vitamin C to remediate Cr(VI)-contaminated soils and groundwater.

Ascorbic Acid↗

PubMed2005

Role of CD97(stalk) and CD55 as molecular markers for prognosis and therapy of gastric carcinoma patients.

OBJECTIVES: To explore the mechanism of development and aggressiveness in gastric carcinomas by investigating the expression and role of CD97 and its cellular ligand CD55 in gastric carcinomas. METHODS: Tumor and corresponding normal mucosal tissue, collected from 39 gastric carcinoma patients, were examined by immunohistochemistry and RT-PCR for the expression of CD97 and CD55. RESULTS: CD97(stalk) was strongly stained on scattered tumor cells or small tumor cell clusters at the invasion front of gastric carcinomas. The expression of CD97(stalk) was frequently observed in tumors of stage I and T1 gastric carcinoma patients. The expression of CD97(stalk) between Stage I and Stage II, III, IV specimens showed significant difference (P<0.05), between T1 and T2, T3, T4 specimens also showed significant difference (P<0.05). Specimens with tumor invasion depth limited in mucosa of T1 specimens showed higher positive CD55 expression than specimens with the same tumor invasion depth in T2, T3, T4 specimens, the expression of CD55 between T1 and T2, T3, T4 specimens was significantly different (P<0.05). There was strong correlation between the distribution patterns of CD97(stalk) and CD55 on tumor tissues (r=0.73, P<0.05). Signet ring cell carcinomas frequently contained strong CD97(stalk) and CD55-staining. CONCLUSIONS: Our results suggest that CD97(stalk) is probably involved in the growth, invasion and aggressiveness of gastric carcinomas by binding its cellular ligand CD55. CD97(stalk) and CD55 could be useful as molecular markers for prognosis and therapy of gastric carcinoma patients.

Antigens, CD↗

PubMed2005

Removal of hexavalent chromium from aqueous solution by iron nanoparticles.

Groundwater remediation by nanoparticles has received increasing interest in recent years. This report presents a thorough evaluation of hexavalent chromium removal in aqueous solutions using iron (Fe(0)) nanoparticles. Cr(VI) is a major pollutant of groundwater. Zero-valent iron, an important natural reductant of Cr(VI), is an option in the remediation of contaminated sites, transforming Cr(VI) to essentially nontoxic Cr(III). At a dose of 0.4 g/L, 100% of Cr(VI) (20 mg/L) was degraded. The Cr(VI) removal efficiency decreased significantly with increasing initial pH. Different Fe(0) type was compared in the same conditions. The reactivity was in the order starch-stabilized Fe(0) nanoparticles>Fe(0) nanoparticles>Fe(0) powder>Fe(0) filings. Electrochemical analysis of the reaction process led to the conclusion that Cr(OH)(3) should be the final product of Cr(VI). Iron nanoparticles are good choice for the remediation of heavy metals in groundwater.

Chromium↗

PubMed2005

[Recombinant adeno-associated virus carrying hepatitis B virus C gene (rAAV-HBV-C) effectively pulses dendritic cells (DC) without affecting their maturity].

OBJECTIVE: Recombinant virus pulsated dendritic cells (DCs) may affect their survival, growth and maturity. This study is to test the infection efficiency of recombinant adeno-associated virus carrying hepatitis B core antigen (rAAV-HBV-c) to DCs and the growth and maturity of them. METHODS: Peripheral blood mononuclear cells (PBMCs) were isolated from healthy blood donors. Adherent monocytes were pulsed by rAAV-HBV-c and 293 lysate as controls on the first day of isolation. DCs were cultivated in AIM-V media with 1000 u/ml granulocyte macrophage stimulating factor (GM-CSF), 1000 u/ml interleukin-4 (IL-4) and 50 ng/ml tumor necrosis factor-alpha (TNFalpha) separately in vitro. DCs were examined at different times and the expressions of several clusters of differentiations (HLADR, CD14, CD80, CD83, CD86) were studied using FACS after being cultured for 7 days. The transcription and expression of HBV-C gene were analyzed by reverse transcription-polymerase chain reaction (RT-PCR) and intracellular staining fluorescence activated cell sorter (FACS), respectively. RESULTS: The rAAV-HBV-c infected and uninfected monocytes gradually matured and their morphology had no significant differences. The CDs expressed on the surfaces of the two groups of DCs were also similar (HLADR: 96.1% vs. 94.5%; CD86: 87.7% vs. 89.8%; CD83: 75.6% vs. 78%; CD80: 52% vs. 54.3%; CD14: 6.4% vs. 4.5%). HBV-C gene mRNA expression was measured using RT-PCR and 89.5% of the rAAV-HBV-c infected DCs showed their protein expression using FACS. CONCLUSION: rAAV-HBV-c can effectively pulse DCs without affecting the growth and maturity of them.

Cells, Cultured↗

PubMed2005

[The role of myofibroblast in the development of pathological scar].

OBJECTIVE: To study the effect of myofibroblast on the development of pathological scar. METHODS: From 1998 to 2000, 14 cases of keloid(k), 13 cases of hypertrophic scar(HS), and 7 cases of scar were studied through immunohistochemistry and electron microscope. RESULTS: Myofibroblasts were often observed in the hypertrophic HS by electron microscope, but no myofibroblast was observed in the K and NS. alpha-SM-actin was expressed in fibroblast of HS, but was not expressed in K and NS. CONCLUSION: Myofibroblast may play a role in the development of hypertrophic scar. The difference between the absence of myofibroblast in keloid and the invasion of keloid deserves further study.

Actins↗

PubMed2005

[A preliminary investigation on safety evaluation system for health foods].

OBJECTIVE: In order to guarantee the safety of health foods, a safety evaluation system has been initially proposed. METHOD: Based on both experienced and experimental safe data of health foods, different safety criteria could be divided. RESULT: A safety evaluation system with five criteria has been finally established, ingredients listed in the first three safe criteria were suitable for health foods. CONCLUSION: This system could be applied for the selection of relevant ingredients of health foods at R&D stage, and it would be improved after certain period of implementation.

Consumer Product Safety↗

PubMed2005

[Binding and inhibition of adeno-associated virus Rep78 protein with hepatitis B virus C promoter].

OBJECTIVES: Adeno-associated virus (AAV) Rep78 is known for its inhibitory effects on replication of several viruses and oncogenes transformations. The study was to investigate the effect of Rep78 on hepatitis B virus C (HBV-C) gene and the mechanism of it. METHODS: HBV-C promoter and HBV-C gene with its promoter were amplified by PCR and labeled with 32P-ATP. Electrophoretic mobility shift assay (EMSA) and in vitro transcription were utilized to detect the binding of MBP-Rep78 with HBV-C promoter and the transcription of HBV-C gene. RESULTS: EMSA showed that by increasing the amount of Rep78 protein from 0.1 microg to 1.0 microg, the binding bands got stronger in a dose-dependent manner. In addition, Rep78 antibody was used to certify the specificity of this binding. The compound of Rep78, Rep78 antibody and HBV-C promoter were seen as super shift bands in EMSA. Meanwhile, HBV-C gene transcription was significantly inhibited by in vitro transcription which meant that Rep78 could not only bind with HBV-C promoter, but also could inhibit the transcription of HBV-C gene. CONCLUSION: AAV Rep78 could inhibit the transcription of HBV-C gene through its binding with HBV-C promoter.

DNA-Binding Proteins↗

PubMed2005

[Studies on HPLC fingerprint of the hydrophilic constituents of Valeriana medicinal plants].

OBJECTIVE: To establish the fingerprint of the hydrophilic constituents of Valeriana medicinal plants. METHOD: The HPLC-UV assay was used to establish the fingerprint of the hydrophilic constituents of Valeriana medicinal plants. RESULT: The HPLC fingerprint profiles of the hydrophilic constituents of Valeriana medicinal plants contains 12 common peaks. The relative retention time and the ranges of relative area of the common peaks were determined. CONCLUSION: The fingerprint profile can be used for the identification and quality control of Valeriana medicinal plants.

Chromatography, High Pressure Liquid↗

PubMed2005

[Influence of electromagnetic irradiation on P450scc mRNA expression in rat testis tissues and protective effect of the shield].

OBJECTIVE: To study the influence of electromagnetic irradiation on cytochrome P450 cholesterol side chain lyase (P450scc) in adult rat testis tissues and to assess the protective effect of the copper shield. METHODS: Healthy male Wistar rats were randomized into a control group, an electromagnetic irradiation group and a wholly shielded group (with the copper shielding net). The electromagnetic irradiation group and the shielded group were set for 4 phases of 3, 6, 24 and 72 hours after irradiation, 15 rats for each phrase. The testosterone contents in the serum of the irradiated rats at 3, 6, 24 and 72 hours and in that of the controls were measured by radioimmunoassay(RIA), and so was the level of the P450scc mRNA in the testis tissues by semi-quantitative RT-PCR. And the effect of the copper shielding net on testosterone and P450scc mRNA was observed. RESULTS: The contents of testosterone and the P450scc mRNA level in the irradiated group were significantly lower than in the control rats, decreased by 83.9% and 56.9% at 3 hours (P < 0.01), 54.8% and 27.3% at 6 hours (P < 0.01), restored to normal at 24 hours, but again reduced by 60.1% and 56.1% respectively (P < 0.01). While in the shielded group, no significant change was observed either in the testosterone of the serum or in the P450scc mRNA expression in the testis tissues. CONCLUSION: Electromagnetic irradiation may affect the transcription of P450scc in adult rat Leydig cells and thereby decrease the testosterone synthesis. Whole-body shielding with the copper net may achieve satisfactory effect.

Animals↗

PubMed2005

[Effects of ketamine and midazolam combination anesthesia on focal cerebral ischemia injury in rats].

OBJECTIVE: We investigated the effects of anesthesia with ketamine and midazolam on focal cerebral ischemia injury, and evaluated the neuroprotective properties of this combination during surgical procedures. METHODS: Thirty male Sprague-Dawley rats were subjected to permanent middle cerebral artery occlusion (MCAO) under ketamine or ketamine-midazolam intraperitoneal anesthesia (n = 15 each). The neurological scoring was performed to determine functional impairment of the brain at 4 h after MCAO. TTC staining of brain slices was used to measure infarct size of the brain at 24 h after MCAO. At day 3 after MCAO, TUNEL staining was employed to detect apoptotic cells in the penumbra. RESULTS: Although neurological scoring (1.57 +/- 0.65 vs 1.74 +/- 0.52) was not significantly different between ketamine and ketamine-midazolam groups (P > 0.05), infarct size and apoptotic cell density in the penumbra were significantly lower in the ketamine-midazolaml group than those in the ketaminel group [infarct size: (24.1 +/- 4.63)% vs (38.48 +/- 4.18)%; apoptotic cells density: (178 +/- 23) cells/mm2 vs (258 +/- 15) cells/mm2, P < 0.05], respectively. CONCLUSION: The above findings suggested that ketamine and midazolam combination might provide neuroprotection during surgical procedures that pose risk for ischemic cerebral injury.

Anesthesia↗