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Biomedical subjects

Hong Gao

Publications and source records attributed to Hong Gao.

At least 91 records · Page 5Linked to original sources
PubMed2003

Voltammetric behavior of 4',7-dimethoxy-3'-isoflavone sulfonic sodium and its enhancement determination in the presence of surfactant.

Voltammetric behavior of 4',7-dimethoxy-3'-isoflavone sulfonic sodium (DISS) was studied by linear sweep voltammetry and cyclic voltammetry. DISS caused two waves between pH 8.0 and 12.0. Above pH 8.0, the peak current of first wave Pc1 of DISS was enhanced in the presence of cetyltrimethylammonium bromide (CTAB). Based on this, a novel method for the determination of DISS was proposed. In Britton-Robinson buffer solution (pH 11.7) containing 9.4 x 10(-6)mol L(-1) CTAB, the peak potential of first wave Pc1 of DISS was -1.59 V (vs standard saturated calomel electrode) and its first-order derivative peak current was proportional to the concentration of DISS in the range 5.0 x 10(-8)-6.0 x 10(-7)mol L(-1) (r=0.998). The detection limit was 1 x 10(-8)mol L(-1), which was 10 times lower than that of the corresponding reduction wave. The method was applied to the determination of DISS in synthetic samples.

Electrochemistry↗
PubMed2003

Genetic algorithms based on wavelet transform for resolving simulated overlapped spectra.

Wavelet transform-based genetic algorithms are proposed for resolving simulated overlapped spectra. Wavelet transform as a derivative method is used for de-noising, for deducting background absorption as well as for peak finding in order to get an estimation of parameters of unresolved spectra. Then genetic algorithms, using the estimations of parameters as input values, are employed to resolve unresolved bands. As a consequence, a good optimized solution was achieved since the reliable estimation of initial values can greatly facilitate the convergence of genetic algorithms and the calculation time is shortened accordingly.

Journal Article↗
PubMed2003

Adipsin, a biomarker of gastrointestinal toxicity mediated by a functional gamma-secretase inhibitor.

Functional gamma-secretase inhibitors (FGSIs) can block the cleavage of several transmembrane proteins including amyloid precursor protein (APP), and the cell fate regulator Notch-1. FGSIs, by inhibiting APP processing, block the generation of amyloid beta (Abeta) peptides and may slow the development of Alzheimer's disease. FGSIs used to inhibit APP processing may disrupt Notch processing, thus interfering with cell fate determination. Described herein is a FGSI-mediated gastrointestinal toxicity characterized by cell population changes in the ileum of rats, which are indicative of Notch signaling disruption. Microarray analysis of ileum from FGSI-treated rats revealed differential expression responses in a number of genes indicative of Notch signaling perturbation, including the serine protease adipsin. We were able to show that FGSI-treated rats had elevated levels of adipsin protein in gastrointestinal contents and feces, and by immunohistochemistry demonstrated that adipsin containing ileum crypt cells were increased in FGSI-treated rats. The mouse Adipsin proximal promoter contains a putative binding site for the Notch-induced transcriptional regulator Hes-1, which we demonstrate is able to bind Hes-1. Additional studies in 3T3-L1 preadipocytes demonstrate that this FGSI inhibits Hes-1 expression while up-regulating adipsin expression. Overexpression of Hes-1 was able to down-regulate adipsin expression and block pre-adipocyte differentiation. We propose that adipsin is a Hes-1-regulated gene that is de-repressed during FGSI-mediated disruption of Notch/Hes-1 signaling. Additionally, the aberrant expression of adipsin, and its presence in feces may serve as a noninvasive biomarker of gastrointestinal toxicity associated with perturbed Notch signaling.

3T3-L1 Cells↗
PubMed2003

[Recombinant adenovirus carrying glial cell line-derived neurotrophic factor gene protect midbrain dopaminergic neurons in mice].

OBJECTIVE: To observe the protective effects of recombinant adenovirus expressing glial cell line-derived neurotrophic factor (Ad-rGDNF) on the midbrain dopaminergic neurons against MPTP damage. METHODS: Recombinant adenovirus carrying LacZ gene (Ad-LacZ) was injected into the murine striatum using the stereotaxic apparatus. The murine brains were perfused and dissected, then stained with X-Gal subsequently at 24 hours, 72 hours, 10 days and 30 days after injection. In another experiment, MPTP was injected subcutaneously into the mice 72 hours after the intrastriatal injection of Ad-rGDNF (1 x 10(8) pfu.ml-1). The murine striatum was removed to evaluate the content of DA, DOPAC and HVA by HPLC-ECD 1 week later. RESULTS: X-Gal staining indicated the expression of LacZ gene 24 hours after injection of Ad-LacZ. Stronger expression was also detected at the end of 72 hours and 10 days, but decreased 30 days later. In addition, the LacZ gene expression was localized and detectable in both neurons and glial cells. There was no apparent cytotoxic effect induced by Ad-LacZ alone. In MPTP-treated mice, the content of dopamine decreased 80% compared to that in the saline-treated ones. The DA content of MPTP + Ad-rGDNF group on injected side was significantly higher than that of MPTP alone group and MPTP + Ad-LacZ group. Changes in the content of DOPAC and HVA followed the same pattern. The ratio of DOPAC/DA and HVA/DA on injected side also decreased significantly. However, no significant change was observed on uninjected side. CONCLUSION: The results suggested that recombinant adenoviral vector expressing rGDNF can protect DA neurons against MPTP injury.

Adenoviridae↗
PubMed2003

[Expression of aFGF in ovarian epithelial cancer and its signal transduction pathway].

OBJECTIVE: To explore the expression of acidic fibroblast growth factor (aFGF) and its receptor FGFR1 in ovarian epithelial cancer and observe the effects of aFGF and TPK inhibitor Genistein on intracellular PKC and ERK activity in ovarian epithelial cancer cells line CAOV3. METHODS: The expression levels of aFGF and FGFR1 were evaluated by RT-PCR and western blot in 40 cases of ovarian epithelial cancer. The activity of PKC and ERK in cells induced by different concentration of aFGF and Genistein were detected by incorporation of [gamma-(32)P]-ATP into exogenous substrate. RESULTS: The expression levels of aFGFmRNA and FGFR1mRNA in the ovarian epithelial cancer were 0.981 +/- 0.130 and 1.047 +/- 0.148, respectively. Compared with normal ovary, ovarian tumor like condition and benign ovary tumors, the difference was significant (P < 0.05). The expression levels in stage III - IV were significantly higher than those in stage I - II (P < 0.05). There were overexpression of aFGF and FGFR1 in the ovarian epithelial cancer in western blot, too. The intracellular PKC and ERK activity increased with aFGF in a dose dependent manner, Genistein suppressed the intracellular PKC and ERK activity also in a dose dependent manner. CONCLUSION: aFGF may play an important role in carcinogenesis, development and invasion of ovarian epithelial cancer. Its receptor in human ovarian cancer cell line CAOV3 possessed TPK activity. These tyrosine-specific protein phosphorylation may initiate a cascade of biochemical events, which may increase the intracellular PKC and ERK activity. PKC and ERK locate downstream of TPK in CAOV3 cell line.

Adult↗
PubMed2003

Comparative study on the immunogenicity between recombinant MS-Sj26GST vaccine and recombinant BCG-Sj26GST vaccine in Schistosoma japonicum.

The BALB/c mice were immunized with rMS-Sj26GST and rBCG-Sj26GST vaccine in Schistosoma japonicum by subcutaneous injection. After they were immunized for 8 weeks, the eyeballs were removed to get blood and macrophages of abdominal cavity and spleen cells were harvested. The lymphocytic stimulating index (SI) was used to measure the cellular proliferating ability and NO release was used to measure the phagocytic activity of the macrophages. By using ELISA kit, the levels of interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) in serum and the splenic lymphocytic cultured supernatant were detected. The results showed that after the mice were immunized with 10(6) CFU of rMS-Sj26GST and rBCG-Sj26GST vaccine separately by subcutaneous injection, proliferating ability of splenic lymphocytes in the mice showed no difference (P > 0.05), but both were significantly increased as compared with that in the control group (P < 0.05); The contents of NO in the intraperitoneal macrophages of rMS-Sj26GST vaccine group were significantly lower than in the control group (P < 0.001) and rBCG-Sj26GST vaccine group (P < 0.01); The levels of serum IL-2 in the rMS-Sj26GST vaccine group were significantly increased as compared with that in the control group (P < 0.001), vector group (P < 0.01) and rBCG-Sj26GST vaccine group (P < 0.05); The contents of serum IFN-gamma in the rMS-Sj26GST vaccine group were significantly increased as compared with that in the control group (P < 0.01) and rBCG-Sj26GST vaccine group (P < 0.05), The contents of IFN-gamma in the cultured supernatant were significantly lower than those of rBCG-Sj26GST vaccine group (P < 0.001), but were significantly increased as compared with that in the control group (P < 0.01). It was indicated that both vaccines could enhance the immune response of the mice, but rMS-Sj26GST vaccine had stronger immunogenicity than rBCG-Sj26GST vaccine.

Animals↗
PubMed2003

Construction and characterization of a novel recombinant single-chain variable fragment antibody against White Spot Syndrome Virus from shrimp.

An antibody phage display library against White Spot Syndrome Virus (WSSV) was constructed. After four rounds of panning against WSSV, 192 out of 480 clones displayed WSSV binding activity. One of the positive clones, designated A1, had relatively higher activity specifically binding to WSSV. A1-soluble, single-chain fragment variable (scFv) antibody has an affinity constant (K(aff)) of 2.02+/-0.42x10(9) M(-1). Dot blot assays showed that A1-soluble scFv could detect WSSV directly from shrimp hemolymph after 24-h feeding infection by WSSV. A1 scFv has potential for the development of a cheap, simple and sensitive diagnostic kit for WSSV in the field.

Amino Acid Sequence↗
PubMed2003

The expression of epidermal growth factor and transforming growth factor-beta1 in the stenotic tissue of congenital pelvi-ureteric junction obstruction in children.

PURPOSE: The aim of this study was to test the hypothesis that expression of epidermal growth factor (EGF) and transforming growth factor-beta 1 (TGF-beta 1) may be altered in stenotic tissue of patients with congenital hydronephrosis caused by pelviureteric junction (PUJ) obstruction and to evaluate the role of these 2 growth factors. METHODS: The expression of EGF and TGF-beta 1 was evaluated in tissue specimens in 25 children with PUJ obstruction and 15 controls with normal PUJs by immunohistochemistry, in situ hybridization, and reverse transcriptase polymerase chain reaction (RT-PCR) techniques. All the signals of mRNA products were normalized to the mRNA levels of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) a housekeeping gene, as a ratio. RESULTS: On RT-PCR study, the amount of TGF-beta 1 mRNA in stenotic tissue was higher than in controls, in addition, EGF gene expression in the obstructed junction was significantly lower than in normal junctions. The TGF-beta 1 to GAPDH ratio was 0.57 +/- 0.26 and 0.36 +/- 0.19 in the stenotic tissue and the normal ureter, respectively (P =.012). The EGF to GAPDH ratio was 0.17 +/- 0.08 and 0.37 +/- 0.14 in the stenotic tissue and the normal ureter, respectively (P =.0001). Furthermore, the positive correlations were found between TGF-beta1 gene and protein expression (r = 0.601; P =.001), TGF-beta 1 gene and drainage clearance half-time (T1/2) (r = 0.474; P =.017), TGF-beta 1 protein expression, and T1/2 (r = 0.516; P =.008). A negative correlation was found between EGF gene and T1/2 (r = -0.448; P =.025). On immunolabeling and in situ hybridization labeling, the expression of TGF-beta 1 protein was strongly positive and confined to the muscle cells, spindle cells, and collagen fibers in the stenotic tissue; the expression of TGF-beta 1 mRNA was moderately positive and mainly distributed in the collagen of the stenotic segment, both the expression of EGF protein and mRNA were negative in the normal ureter. CONCLUSIONS: There were increased TGF-beta 1 mRNA expression and decreased EGF mRNA expression in the stenotic tissue after clinical ureteropelvic junction obstruction. The alteration of EGF and TGF-beta 1 expression may be involved in the pathogenesis of congenital hydronephrosis.

Child↗
PubMed2003

Multiplex inhibitor screening and kinetic constant determinations for yeast hexokinase using mass spectrometry based assays.

An electrospray ionization mass spectrometry based assay was developed for kinetic measurements and inhibitor screening of yeast hexokinase. There is considerable discrepancy in the literature as to the accuracy of kinetic data obtained for hexokinase. In the assay described herein, the product, glucose 6-phosphate was directly monitored by ion trap mass spectrometry and quantified using an internal standard, 2 deoxy-glucose 6-phosphate. The kinetic parameters, K(M) and V(max) for the two substrates were determined without using a coupling enzyme as is normally employed in the traditional spectrophotometric assay for systems lacking a chromophore. In addition, hexokinase was successfully immobilized onto an amino-link gel, and a mock library was screened against the immobilized enzyme for the identification of possible inhibitors. After comparing the mass spectra of the library before and after incubation, trehalose 6-phosphate, ADP, and oxidized glutathione were differentiated from other weak or non-inhibitors. Inhibition behavior of ADP with respect to ATP was further evaluated with the ESI-MS assay and the value of K(i) was determined. This ESI-MS assay was demonstrated to be both accurate and precise for determining kinetic constants and for identifying enzyme inhibitors.

Drug Evaluation, Preclinical↗
PubMed2003

Investigation of ion/molecule reactions as a quantification method for phosphorylated positional isomers. an FT-ICR approach.

A rapid and accurate method of quantifying positional isomeric mixtures of phosphorylated hexose and N-acetylhexosamine monosacchrides by using gas-phase ion/molecule reactions coupled with FT-ICR mass spectrometry is described. Trimethyl borate, the reagent gas, reacts readily with the singly charged negative ions of phosphorylated monosaccharides to form two stable product ions corresponding to the loss of one or two neutral molecules of methanol from the original adduct. Product distribution in the ion/molecule reaction spectra differs significantly for isomers phosphorylated in either the 1- or the 6-position. As a result, the percents of total ion current of these product ions for a mixture of the two isomers vary with its composition. In order to determine the percentage of each isomer in an unknown mixture, a multicomponent quantification method is utilized in which the percents of total ion current of the two product ions for each pure monosaccharide phosphate and the mixture are used in a two-equation, two-unknown system. The applicability of this method is demonstrated by successfully quantifying mock mixtures of four different isomeric pairs: Glucose-1-phosphate and glucose-6-phosphate; mannose-1-phosphate and mannose-6-phosphate; galactose-1-phosphate and galactose-6-phosphate; N-acetylglucosamine-1-phosphate and N-acetylglucosamine-6-phosphate. The effects of mixture concentrations and ion/molecule reaction conditions on the quantification are also discussed. Our results demonstrate that this assay is a fast, sensitive, and robust method to quantify isomeric mixtures of phosphorylated monosaccharides.

Fourier Analysis↗
PubMed2003

[Effects of Yifei Kangliu Oral Liquid on cell cycle and protein-nucleic acid synthesis of experimental lung cancer].

OBJECTIVE: To explore the effect of the traditional Chinese medicine Yifei Kangliu (YFKL) Oral Liquid on the proliferation, cell cycle and protein-nucleic acid synthesis of murine Lewis lung cancer cell and human lung adenocarcinoma cell line SPC-A-1. METHODS: The inhibiting rates of tumor growth were calculated by weighing the weight of tumor inoculated in vivo, combined by counting cancer cells in vitro. The ratio of the cell cycle and exponents of DNA, RNA, and protein were measured by flow cytometry (FCM). RESULTS: The inhibiting rate of tumor growth in the treated group with YFKL Oral Liquid was 30.38% (P<0.05). The proportion of cells in S phase of the treated groups with YFKL Oral Liquid was lower than that of the control group. In the group with most significant result, 72% of the cells were stagnated in G0/G1 phase. The inhibiting rates of DNA, RNA and protein in murine Lewis lung cancer were 7.4%, 23.73% and 23.31% respectively. In SPC-A-1 cell line, the inhibiting rates were 9.3%, 10.1% and 14.7% respectively, demonstrating amplified effects on lower levels. CONCLUSION: YFKL Oral Liquid significantly inhibited the proliferation of murine Lewis lung cancer cell and human lung adenocarcinoma cell line SPC-A-1 by blocking the cancer cells entering the proliferative phase resulted from its inhibition of DNA.

Adenocarcinoma↗
PubMed2003

[Prognostic significance of peripheral blood cell and bone marrow megakaryocyte counts in patients with idiopathic thrombocytopenic purpura].

To clarify the prognostic contribution of peripheral blood cell and bone marrow megakaryocyte counts in patients with idiopathic thrombocytopenic purpura, a series of data of 299 ITP patients including the counts of peripheral white blood cells and platelets, their increase potentials after treatment and the megakaryocytic counts on the bone marrow smears at diagnosis as well were collected and retrospectively analyzed to correlate with the disease development. The results showed that peripheral white blood cell and platelet counts at diagnosis were not associated with the prognosis, but positively associated with the increment of platelet counts after treatment. The cure rate reached up to 94.9% in the group with the platelet level restored to 100 x 10(9)/L in two weeks of therapy. The numerous megakaryocyte counts in bone marrow at diagnosis indicated good prognosis that the cure rate was up to 86.1% when the counts were more than 100 per 1.5 x 3 cm of smear. In conclusion, bone marrow examination on the quantity and quality of megakaryocyte would be critical for diagnosis and evaluation of the prognosis. Consecutive platelet counts during therapy is useful to estimate the disease development.

Adolescent↗
PubMed2003

[Expression of survivin gene and its relation with the expression of bcl-2 and bax protein in epithelial ovarian cancer].

OBJECTIVE: To study the expression of apoptosis related gene survivin and its relation with expression of bcl-2, bax protein in epithelial ovarian cancer. METHODS: Expression of survivin gene was evaluated by reverse transcription polymerase chain reaction (RT-PCR) in 35 cases of epithelial ovarian cancer, and compared with that in 10 cases of borderline cancer, 10 cases of benign tumors and 10 cases of normal tissue. Expression of bcl-2 and bax was detected by immunohistochemistry streptomycin-avidin-biotin-peroxidase complex (SABC) method, and correlation between them was analyzed. RESULTS: Expression of survivin gene was detected in a significantly greater proportion in epithelial ovarian cancer and borderline tumors than benign tumors and normal tissue. There was no relationship between survivin gene expression and FIGO stage, histologic grade, pathological type and lymphatic metastasis. Expression of bcl-2 and bax protein was positively and negatively correlated with expression of survivin gene respectively. CONCLUSION: survivin gene may play an important role in pathogenesis of ovarian cancer, apoptosis related gene bcl-2 may have a synergic role and bax have an antagonistic role with survivin gene in formation and progression of ovarian cancer.

Adolescent↗
PubMed2003

[Effect of intrauterine acute ischemic-hypoxia on the expression of lung SP-A and SP-B in neonatal rats].

OBJECTIVE: Neonatal asphyxia is one of the main causes for the acute respiratory distress syndrome (ARDS) in full-term newborns. Now it is believed that the reduced amount and abnormal function of pulmonary surfactant due to various causes is a major factor leading to acute lung injury. This study aimed at using an intrauterine acute ischemic-hypoxia rat model and investigating the effect of intrauterine acute ischemic-hypoxia on the expression of surfactant protein A (SP-A) and surfactant protein B (SP-B) in neonatal rat lungs. METHODS: The rat model of acute intrauterine ischemic-hypoxia was established by ligating the unilateral uterine horn vessels of Wistar rats at the 21st gestational day. While the rat pups from the other side of the uterus, of which the uterine horn vessel was not ligated, were the sham-operation group. Rat pups were delivered by cesarean section at the 20, 30 and 40 min following the ischemic-hypoxia insult. The rat pups delivered by cesarean section from the gestation of 21 days were the normal control group. There were 42 rat pups and 6 pups in each group in this study. The distribution of SP-B protein in the neonatal rat lungs of different period of ischemia was examined by using SABC method. The average gray value of SP-B staining in type II alveolar epithelial cells were measured by Universal Imaging Porporation with Meta Morph software. The reverse transcription polymerase chain reaction (RT-PCR) was performed to quantitate the expression of SP-A and SP-B mRNA. RESULTS: Following the intrauterine acute ischemic-hypoxia, the numbers of type II alveolar epithelial cells with the positive SP-B staining were markedly declined. The average gray values at the 20, 30 and 40 min after the ischemia were 78.89 +/- 1.08, 79.69 +/- 0.13 and 80.00 +/- 0.63, respectively, which increased significantly compared with the normal control group (76.13 +/- 0.43, P < 0.01). The expression of SP-A and SP-B mRNA was weak following the ischemic-hypoxia insult. The relative amounts of SP-A (1.16 +/- 0.06, 1.14 +/- 0.01 and 1.13 +/- 0.04, respectively) and SP-B (0.81 +/- 0.02, 0.78 +/- 0.02 and 0.79 +/- 0.04, respectively) at the 20, 30 and 40 min after the ischemia were reduced significantly compared with controls (1.27 +/- 0.09 and 0.89 +/- 0.06, respectively, P < 0.05 and < 0.01) and reduced gradually following the prolongation of the insult. There were no significant differences (P > 0.05) between the normal and sham operation control groups on the expressions of SP-B protein as well as the SP-A and SP-B mRNA. CONCLUSION: The reduced synthesis of SP-B protein and the reduced expression of SP-A and SP-B mRNA might be caused by intrauterine acute ischemic-hypoxia, which may support theoretically the early application of pulmonary surfactant including SP-A and SP-B for treating the lung injuries of asphyxia in newborns.

Animals↗
PubMed2002

Antidiabetic action of a liver x receptor agonist mediated by inhibition of hepatic gluconeogenesis.

The oxysterol receptors LXR (liver X receptor)-alpha and LXRbeta are nuclear receptors that play a key role in regulation of cholesterol and fatty acid metabolism. We found that LXRs also play a significant role in glucose metabolism. Treatment of diabetic rodents with the LXR agonist, T0901317, resulted in dramatic reduction of plasma glucose. In insulin-resistant Zucker (fa/fa) rats, T0901317 significantly improved insulin sensitivity. Activation of LXR did not induce robust adipogenesis but rather inhibited the expression of several genes involved in hepatic gluconeogenesis, including phosphoenolpyruvate carboxykinase (PEPCK). Hepatic glucose output was dramatically reduced as a result of this regulation. Nuclear run-on studies indicated that transcriptional repression was primarily responsible for the inhibition of PEPCK by the LXR agonist. In addition, we show that the regulation of the liver gluconeogenic pathway by LXR agonists was a direct effect on hepatocytes. These data not only suggest that LXRs are novel targets for diabetes but also reveal an unanticipated role for these receptors, further linking lipid and glucose metabolism.

Animals↗
PubMed2002

Phospholipid transfer protein is regulated by liver X receptors in vivo.

Liver X receptors (LXR) belong to the nuclear receptor superfamily that can regulate important lipid metabolic pathways. The plasma phospholipid transfer protein (PLTP) is known to mediate transfer of phospholipids from triglyceride-rich lipoproteins to high density lipoprotein (HDL) and plays a critical role in HDL metabolism. We report here that a specific LXR agonist, T0901317, elevated HDL cholesterol and phospholipid in C57/BL6 mice and generated enlarged HDL particles that were enriched in cholesterol, ApoAI, ApoE, and phospholipid. The appearance of these HDL particles upon oral dosing of T0901317 in C57/BL6 mice was closely correlated with the increased plasma PLTP activity and liver PLTP mRNA levels. Nuclear run-on assay indicated that the effect of LXR agonist on PLTP expression was at the transcriptional level. In mouse peritoneal macrophage cells, PLTP expression was also up-regulated by the LXR/RXR (retinoid X receptor) heterodimer. However, cholesterol efflux in mouse peritoneal macrophage cells from PLTP-deficient mice (PLTP0) was not significantly different from wild type animals. Although in PLTP-deficient mice, the induction of HDL cholesterol as well as HDL particle size increase persisted, the extent of the induction was greatly attenuated. We conclude that PLTP is a direct target gene of LXRs in vivo and plays an important role in LXR agonist-mediated HDL cholesterol and size increase in mice.

Animals↗