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Biomedical subjects

Jing Dong

Publications and source records attributed to Jing Dong.

At least 37 records · Page 2Linked to original sources
PubMed2005

Electrochromatographic evaluation of a silica monolith capillary column for separation of basic pharmaceuticals.

A silica-based monolithic capillary column was prepared via a sol-gel process. The continuous skeleton and large through-pore structure were characterized by scanning electron microscopy (SEM). The native silica monolith has been successfully employed in the electrochromatographic separation of beta-blockers and alkaloids extracted from traditional Chinese medicines (TCMs). Column efficiencies greater than 250 000 plates/m for capillary electrochromatography (CEC) separation of basic compounds were obtained. It was observed that retention of basic pharmaceuticals on the silica monolith was mainly contributed by a cation-exchange mechanism. Other retention mechanisms including reversed-phase and normal-phase mechanisms and electrophoresis of basic compounds also played a role in separation. A comparison of the differences between CEC and capillary zone electrophoresis (CZE) separation was also discussed.

Adrenergic beta-Antagonists↗
PubMed2005

Capillary electrochromatography with a neutral monolithic column for classification of analytes and determination of basic drugs in human serum.

Capillary electrochromatography (CEC) using a neutral hydrophobic polymer-based monolithic column has been developed for classification of analytes based on their acidity and charges of group. The monolithic columns were prepared by in situ copolymerization of lauryl methacrylate and ethylene dimethacrylate without any charged monomers in the reaction mixture. The ionic analytes will only be driven by their electrophoretic mobilities and were separated on the basis of their differences in electrophoretic mobility and in hydrophobic interaction with the stationary phase. Only negatively or positively charged analyte (acid or basic) migrated toward detection window in a single run by applying negative or positive voltage. The CEC system was also applied for the analysis of basic drugs in human serum by internal standard method using acidic running buffer. The sample of human serum spiked with basic drugs was directly injected after a simple sample pretreatment. The calibration curves with regression coefficients (0.9995-0.9997) in the range of 0.318-80 microg/mL were obtained with the limits of detection being below 0.15 microg/mL. The intra- and inter-day precisions, determined as relative standard deviations, were less than 4.21%.

Atenolol↗
PubMed2005

Preparation of monolithic silica column with strong cation-exchange stationary phase for capillary electrochromatography.

A monolithic silica based strong cation-exchange stationary phase was successfully prepared for capillary electrochromatography. The monolithic silica matrix from a sol-gel process was chemically modified by treatment with 3-mercaptopropyltrimethoxysilane followed by a chemical oxidation procedure to produce the desired function. The strong cation-exchange stationary phase was characterized by its substantial and stable electroosmotic flow (EOF), and it was observed that the EOF value of the prepared column remained almost unchanged at different buffer pH values and slowly decreased with increasing phosphate concentration in the mobile phase. The monolithic silica column with strong cation-exchange stationary phase has been successfully employed in the electrochromatographic separation of beta-blockers and alkaloids extracted from traditional Chinese medicines (TCMs). The column efficiencies for the tested beta-blockers varied from 210,000 to 340,000 plates/m. A peak compression effect was observed for atenolol with the mobile phase having a low phosphate concentration.

Journal Article↗
PubMed2005

Subcellular distribution and chemical form of Cd and Cd-Zn interaction in different barley genotypes.

A hydroponic experiment was carried out to study the genotypic difference in subcellular distribution and chemical form of Cd and Zn uptake and their interaction in four barley genotypes. Increased Cd level in the medium caused a significant increase of Cd concentration in all fractions of roots/shoots, with most accumulation in FI (cell wall) and FIV (soluble). In root, the greatest amount of Cd was found in extraction solution of 2% HAC or 0.6M HCl, followed by 1M NaCl (20%), and lowest in extraction of 80% ethanol or d-H2O. While in shoot, the highest value of Cd accumulation was recorded in the fractions extracted by 1M NaCl and 2% HAC, followed by 0.6M HCl or d-H2O, and least in 80% ethanol extraction solution. There was a distinct difference among genotypes in Cd concentration in subcellular and chemical forms and it was found that the Cd-sensitive genotype Wumaoliuling, in comparison with the other three Cd-resistant genotypes, had higher Cd concentration in chloroplast-shoot/trophoplast-root (FII), membrane and organelle (FIII) and in inorganic and water-soluble Cd of roots, while lower in FI, FIV and pectates/protein integrated Cd. After 48 h of Cd treatment, the plants were replaced into Cd-free nutrient solution and grown for 72 h, a significant decrease in Cd concentration of root FI was observed, with less Cd reduction in Wumaoliuling. In comparison with control (no Cd), addition of Cd significantly increased Zn accumulation in chloroplast (FII), with least increase in Wumaoliuling. The Zn content in the other 3 fractions decreased significantly with addition of Cd, especially in roots, while Wumaoliuling was the most severely affected genotype. Moreover, it could be suggested Zn supplement could significantly reduce Cd concentration in root trophoplast and in shoot soluble fraction of Cd-treated plants.

Cadmium↗
PubMed2005

Congenital iodine deficiency and hypothyroidism impair LTP and decrease C-fos and C-jun expression in rat hippocampus.

Iodine is essential for the synthesis of triiodothyronine (T(3)) and thyroxine (T(4)). Iodine deficiency leads to inadequate thyroid hormone. Thyroid hormones deficiency during brain development affects cognitive functions, such as attention, learning, and memory. However, the mechanism underlying these deficits is unclear. To investigate the role of iodine deficiency and hypothyroidism in synaptic plasticity, this study examined the induction of long-term synaptic plasticity (LTP) and expression of immediate early (IEA) gene proteins in rat hippocampus following congenital iodine deficiency or hypothyroidism. Through gestation and lactation, iodine-deficient or hypothyroid dam rats were administered with either iodine-deficient diet or methimazole-added drinking water. Exposure was terminated on postnatal day (PN) 30. In hippocampus of pup rats, the induction of LTP in area CA1 was determined on PN60 and the expression of c-fos and c-jun proteins was examined on PN20, PN30 and PN60. Compared to control pups, both treated groups have shown: (1) significantly lower concentrations of serum FT(3) and FT(4), (2) much smaller population spike (PS) amplitude (p<0.01) and field-excitatory postsynaptic potential (f-EPSP) slope induced by high-frequency stimulation (HFS) (P<0.01), and (3) significantly lower integrated optical density (IOD) total of c-fos and c-jun expression (P<0.05 or P<0.01). In summary, iodine deficiency and hypothyroidism during critical periods of brain development impair LTP induction and decrease the expression of c-fos and c-jun proteins in hippocampus.

Aging↗
PubMed2005

Environmental mycological study and allergic respiratory disease among tobacco processing workers.

This study presents the results of an investigation of respiratory symptoms, lung function, chest X-ray examinations, analysis of specific IgE antibodies and skin prick tests to fungi on 130 tobacco-processing workers and 112 control workers. Industrial hygiene survey and environmental mycological studies were also performed. The average dust concentrations ranged from 13.76 to 29.55 mg/m(3) in the tobacco processing workshops. Also, the numbers of fungi colonies in the processing environments were much higher than those in the control environments. The prevalences of chronic respiratory or nasal symptoms in exposed workers were significantly higher than those in control workers (p<0.05 or p<0.01). The prevalences of lung function abnormalities in the exposed workers were significantly higher than those in control workers (p<0.05). The positive prevalences of specific IgE reactions to fungi (26.92% for A.fumigatus and 51.54% for Rhizopus nigricans) in exposed workers were also significantly higher than those in control workers (p<0.01). The positive prevalences of the skin prick test showed that 18.46% of the exposed workers were positive to A. fumigatus and 23.85% were positive to Rhizopus nigricans. Our results suggested that tobacco processing workers may develop respiratory diseases related to tobacco dust and we consider that fungi might be one of the allergens causing allergic respiratory or nasal diseases in tobacco processing workers.

Adult↗
PubMed2005

Effect of cadmium on growth and photosynthesis of tomato seedlings.

A hydroponic experiment carried out to study the effect of five Cd levels on growth and photosynthesis of two tomato cultivars showed that the addition of 0.1 micromol/L Cd induced a slight increase in plant height of Hezuo 903 and the SPAD (the Soil-Plant Analyses Development) value of the 2 cultivars. However, at higher Cd levels, i.e., 1 and 10 micromol/L, root length and volume, plant height, and SPAD value were all significantly reduced. On an average of the 2 cultivars, exposure to 1 and 10 micromol/L Cd for 33 d reduced plant height by 18.9% and 46.4% and SPAD value by 11.2% and 31.6%, compared with control, respectively. Similarly, root length was reduced by 41.1% and 25.8% and root volume by 45.2% and 63.7%, respectively. The addition of Cd in the growth medium also had significant deleterious effect on net photosynthetic rate (Pn) and intracellular CO(2) concentration (Ci), with Pn being reduced by 27.2% and 62.1% at 1 micromol/L and 10 micromol/L Cd treatments compared to the control, respectively, while Ci increased correspondingly by 28.4% and 39.3%.

Cadmium↗
PubMed2005

[Progress in research on triptolide].

To further understand triptolide, this paper has introduced the pharmacology, pharmacokinetics, toxicity, the clinic application and semi-synthesis of triptolide on basis of importance and significant contents of reference which have been consulted in the past twenty years. Presently triptolide and Tripterygium wilfordii have been a hot spot of modernization of Chinese traditional medicine. It is very important to develop a new dosage form of high effect and low toxicity by making use of advanced technology according to its characteristics.

Animals↗
PubMed2005

[Identification and analysis of a mouse gene homologous to human hepatitis B virus pre-S1 protein-binding protein using the bioinformatics method].

OBJECTIVE: To clone and identify the mouse gene homologous to human hepatitis B virus (HBV) pre-S1 protein-binding protein (PS1BP). METHODS: The human PS1BP cDNA sequence was used as the reference sequence to search homologous mouse cDNA sequence from GenBank established by National Center for Biotechnology (NCBI), National Institute of Health (NIH), for its homologous cDNA sequences of mouse by BLASTn tool. The characteristics of mouse PS1BP protein primary structure were predicted by online software. Finally the genomic DNA structure of mouse PS1BP was deduced and compared. RESULTS: The mouse PS1BP was identified and consisted of 1455 nt, coding a protein of 484 aa. The identity of human and mouse PS1BP protein is 84.92% (411/484). The genomic DNA of mouse PS1BP consisted of 3 exons and 2 introns. CONCLUSION: The identification and characterization of mouse PS1BP cDNA and genomic DNA pave a way for further study of their structures and functions.

Amino Acid Sequence↗
PubMed2005

[Effects of large dose of Astragalus membranaceus on the dendritic cell induction of peripheral mononuclear cell and antigen presenting ability of dendritic cells in children with acute leukemia].

OBJECTIVE: To explore the effects of large dose of Astragalus membranaceus (Astragalus) on the dentritic cell (DC) induction in vitro and augumentation by peripheral mononuclear cell (MNC) and on antigen presenting ability of DC in children with acute leukemia. METHODS: Forty-four children with acute leukemia in complete remission stage were divided into two groups. Twenty patients in the Astragalus (90 g daily) group were treated with large dose of Astragalus (90 g daily) based on conventional chemotherapy for one month, while 24 patients in the control group received chemotherapy alone. MNC were extracted from peripheral blood by wall-sticking method and cultured with such cell factors as interleukin-4, gramulocyte macrophage colony stimulating factor, tumor necrosis factor-alpha for 7-8 days. Phenotype of DC was assayed by flow cytometry and antigen presenting ability of them was assayed by mixed lymphocyte reaction. RESULTS: There was no morphological difference in MNC induced DC between the two groups. The average number of DC in Astragalus group and control group was 4.4 x 10(6) / 2.5 x 10(6) MNC and 2.6 x 10(6) / 2.5 x 10(6) MNC, respectively, showing significant difference (P < 0.001). DC in Astragalus group could stimulate the proliferation of allogeneic lymphocytes strongly, showing significant difference when compared with that in the control group (P < 0.001). Conclusion Large dose of Astragalus could increase the DC induction of MNC and enhance the antigen presenting ability of DC in acute leukemia patients.

Acute Disease↗
PubMed2004

Monolithic column with zwitterionic stationary phase for capillary electrochromatography.

A capillary electrochromatography (CEC) monolithic column with zwitterionic stationary phases was prepared by in situ polymerization of butyl methacrylate, ethylene dimethacrylate, methacrylic acid, and 2-(dimethyl amino) ethyl methacrylate in the presence of porogens. The stationary phases have zwitterionic functional groups, that is, both tertiary amine and acrylic acid groups, so the ionization of those groups on the zwitterionic stationary phase was affected by the pH values of the mobile phase, and further affects the strength and direction of the electroosmotic flow (EOF). Separations of alkylbenzenes and polycyclic aromatic hydrocarbons based on the hydrophobic mechanism were obtained. Separation of various types of polar compounds, including phenols, anilines, and peptides, on the prepared column were performed under CEC mode with anodic and cathodic EOF, and different separation selectivities of those polar analytes were observed on the monolithic capillary column by using mobile phases with different pH values.

Journal Article↗
PubMed2004

Monolithic columns with mixed modes of reversed-phase and anion-exchange stationary phase for capillary electrochromatography.

A capillary electrochromatography (CEC) monolithic column with mixed modes of reversed-phase and anion-exchange stationary phases was prepared by in situ polymerization of 2-(methacryloxy)ethyltrimethylammonium methyl sulfate (MEAMS) and ethylene dimethacrylate (EDMA) in a binary porogenic solvent consisting 1-propanol and 1,4-butanediol. The ammonium groups on the surface of the stationary phase generate an electroosmotic flow (EOF) from cathode to anode, and serve as a strong anion-exchange stationary phase at the same time. The EOF of the stationary phase can be determined by the amount of MEAMS monomer in reaction mixtures during the polymerization. The monolithic stationary phases exhibited reversed-phase chromatographic behavior toward neutral solutes. For charged solutes, hydrophobic as well as electrostatic interaction/repulsion with the monoliths was observed. Separations of aromatic compounds and basic compounds on the prepared column were performed under the mode of CEC. Peak tailing of basic compounds was avoided and the efficient separation of aromatic acids was achieved using neutral mobile phase due to the same direction of EOF and electrophorestic mobility of negatively charged solutes.

Anion Exchange Resins↗
PubMed2004

EGFR-independent activation of p38 MAPK and EGFR-dependent activation of ERK1/2 are required for ROS-induced renal cell death.

2,3,5-Tris-(glutathion-S-yl)hydroquinone (TGHQ), a reactive metabolite of the nephrotoxicant hydroquinone, induces the ROS-dependent activation of MAPKs, followed by histone H3 phosphorylation and oncotic cell death in renal proximal tubule epithelial cells (LLC-PK(1)). Cell death and histone H3 phosphorylation are attenuated by pharmacological inhibition of p38 MAPK or ERK1/2 pathways. Because TGHQ, but not epidermal growth factor (EGF), induces histone H3 phosphorylation and cell death in LLC-PK(1) cells, we hypothesized that there are differences in the mechanisms by which TGHQ and EGF induce activation of the EGF receptor (EGFR). We therefore compared the relative ability of TGHQ, H(2)O(2), and EGF to activate EGFR and MAPKs and found that p38 MAPK activation is EGFR independent, whereas ERK1/2 activation occurs mainly through EGFR activation. TGHQ, H(2)O(2), and EGF induce different EGFR tyrosine phosphorylation profiles that likely influence the subsequent differential kinetics of MAPK activation. We next transfected LLC-PK(1) cells with a dominant negative p38 MAPK-expressing plasmid (pcDNA3-DNp38). TGHQ failed to induce phosphorylation of p38 MAPK and its substrate, MK-2, in pcDNA3-DNp38-transfected cells, indicating loss of function of p38 MAPK. In untransfected, pcDNA3 or pcDNA3-p38 (native)-transfected LLC-PK(1) cells, Hsp27 was intensively phosphorylated after TGHQ treatment, whereas in pcDNA3-DNp38-transfected cells, TGHQ failed to induce Hsp27 phosphorylation. Thus EGFR-independent p38 MAPK and EGFR-dependent ERK1/2 activation by TGHQ lead to the activation of two downstream signaling factors, i.e., histone H3 and Hsp27 phosphorylation, which have in common the potential ability to remodel chromatin.

Animals↗
PubMed2004

Grp78 is essential for 11-deoxy-16,16-dimethyl PGE2-mediated cytoprotection in renal epithelial cells.

11-Deoxy-16,16-dimethyl PGE(2) (DDM-PGE(2)) protects renal proximal tubule epithelial cells (LLC-PK(1)) against the toxicity induced by 2,3,5-tris(glutathion-S-yl)hydroquinone (TGHQ), a potent nephrotoxic and nephrocarcinogenic metabolite of hydroquinone. We have now determined the ability of DDM-PGE(2) to protect against other renal toxicants and report that DDM-PGE(2) only protects against oncotic cell death, induced by H(2)O(2), iodoacetamide, and TGHQ, but not against apoptotic cell death induced by cisplatin, mercuric chloride, or tumor necrosis factor-alpha. DDM-PGE(2)-mediated cytoprotection is associated with the upregulation of at least five proteins, including the major endoplasmic reticulum (ER) chaperone glucose-regulated protein 78 (Grp78). To elucidate the role of Grp78 in oncotic cell death, we used LLC-PK(1) cells in which induction of grp78 expression was disrupted by stable expression of an antisense grp78 RNA (pkASgrp78). As anticipated, DDM-PGE(2) failed to induce Grp78 in pkASgrp78 cells, with a concomitant inability to provide cytoprotection. In contrast, DDM-PGE(2) induced Grp78 and afforded cytoprotection against H(2)O(2), iodoacetamide, and TGHQ in empty vector transfected cells (pkNEO). These data suggest that Grp78 plays an essential role in DDM-PGE(2)-mediated cytoprotection. Moreover, TGHQ-induced p38 MAPK activation is disrupted under conditions of a compromised ER stress response in pkASgrp78 cells, which likely contributes to the loss of cytoprotection. Finally, using two-dimensional gel electrophoresis coupled to matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy, we found that DDM-PGE(2) induced several proteins in pkNEO cells, but not in pkASgrp78 cells, including retinol-binding protein, myosin light chain, and heat shock protein 27. The findings suggest that additional proteins may act in concert with Grp78 during DDM-PGE(2)-mediated cytoprotection against oncotic cell death.

Animals↗
PubMed2004

Induction of ERK1/2 and histone H3 phosphorylation within the outer stripe of the outer medulla of the Eker rat by 2,3,5-tris-(glutathion-S-yl)hydroquinone.

2,3,5-tris-(glutathion-S-yl)-hydroquinone (TGHQ), a metabolite of hydroquinone (HQ), generates reactive oxygen species (ROS) in cultured renal epithelial cells and binds to tissue macromolecules within the rat kidney. The potential mechanisms by which TGHQ induces nephrotoxicity and nephrocarcinogenesis have been examined in cell culture models, but less is known concerning the molecular mechanisms of TGHQ-induced nephrotoxicity in vivo. In LLC-PK1 cells, TGHQ induces phosphorylation of both mitogen-activated protein kinase and histone H3, which likely promotes inappropriate chromatin condensation and mitotic catastrophe. Using the Eker (Tsc-2 mutant) rat as a model, we show by immunohistochemistry that TGHQ (7.5 micromol/kg) selectively induces ERK1/2 phosphorylation within the outer stripe of the outer medulla (OSOM) of the kidney. ERK1/2 phosphorylation is time-dependant, occurring as early as 1 h following treatment, and reaching maximal levels by 4 h. Subsequently, ERK1/2 phosphorylation returns to baseline levels by 24 h post treatment. ERK1/2 phosphorylation was confirmed by western blot analysis of OSOM tissue. Increases in histone H3 phosphorylation occurred subsequent to ERK1/2 phosphorylation (8 h), and reached a peak by 24 h, coincident with histological evidence of tissue necrosis. In contrast to studies in cell culture, neither JNK/SAPK nor p38 MAPK phosphorylation were significantly altered after TGHQ administration in vivo, as evidenced by western blot and immunohistochemical analyses. These data indicate that activation of the ERK1/2 pathway precedes overt cytotoxicity and that the signaling pathways activated by TGHQ in vivo and in vitro differ.

Animals↗
PubMed2004

Comparing study of the effect of nanosized silicon dioxide and microsized silicon dioxide on fibrogenesis in rats.

This study compares the effect of nanosized silicon dioxide (nanosized SiO2) and microsized silicon dioxide (microsized SiO2) particles on fibrogenesis in rats. Wistar rats were instilled intratracheally with saline, 20 mg of nanosized SiO2 or 20 mg of microsized SiO2, and were sacrificed at 1 and 2 months after instillation. The lungs of rats were analysed for the changes of lung/body coefficient and hydroxyproline content. Changes in pathology and fibrotic grade were observed by use of hematoxylin and eosin and Van Gieson dyeing. The expression of interleukin-4 (IL-4) and transforming growth factor-beta1 (TGF-beta1) was observed by use of immunohistochemical technique, and protein expression quantitatively analysed by image analysis. The lung/body coefficient and hydroxyproline content of nanosized SiO2 groups were significantly lower than those of microsized SiO2 groups at both 1 and 2 months after instillation (P<0.05 or P<0.01), but without significant differences from those of saline control groups. At 1 month after instillation, there were mainly cellular nodules (Stage I) in nanosized SiO2 group, while in microsized SiO2 group Stage II, II+ of silicotic nodules were observed. At 2 months after instillation, there were still Stage I of silicotic nodules in nanosized SiO2 group. In microsized SiO2 group mainly Stage II+, III of silicotic nodules were found. Quantity image analysis showed that the expressions of IL-4 and TGF-beta1 in nanosized SiO2 groups were significantly lower than those in microsized SiO2 groups (P<0.01), but without significant difference from those of saline control groups. Our experiment revealed that the effect of fibrogenesis of nanosized SiO2 might be milder than that of microsized SiO2 in rats, potentially resulting from nanoparticals tending to be diffused and easily translocated due to their ultrafine particle size compared to microsized particles.

Animals↗
PubMed2004

[Preparation and toxicity of triptolide-loaded poly (D,L-lactic acid) nanoparticles].

AIM: Investigations on reducing the toxicity of triptolide through poly(D, L-lactic acid) nanoparticles as a drug carrier by oral administration to Wistar rats. METHODS: Triptolide-loaded poly (D, L-lactic acid) nanoparticles (TP-PLA-NPs) were prepared by modified spontaneous emulsification solvent diffusion (modified-SESD). The shape of nanoparticles was observed by transmission electron microscope (TEM). The size distribution and mean diameter were measured by laser light scattering technique. The entrapment efficiency and contents of drug loading were determined by RP-HPLC. The physical state of drug loaded in nanopartiles were primarily investigated by X-ray powder diffractometry. TP-PLA-NPs release behavior in vitro was carried out. After oral administration of the nanoparticles to Wistar rats in 15d, the toxicity for liver and kidney were studied by determining aspartate transaminase (AST), alanine transaminase (ALT) and blood urea nitrogen in serum and concentration of protein in urine. RESULTS: The preparation process adapted to the formulation was as follows: the volume ratio of the aqueous and organic phases was 40/15; the surfactant concentration was 1%; the drug concentration was 0.3%; triptolide-PLA was 1:15 (w/w). The mean diameter was 149.7 nm and the polydispersity index was 0. 088 for the nanoparticles prepared by above conditions. The entrapment efficiency and content of drug loading were 74.27% and 1.36%, respectively. The release behavior of drug in vitro showed an initial burst effect, subsequently a slower rate stage. The results indicated that the liver toxicity (P < 0.01) and kidney toxicity (P < 0.05) caused by triptolide could be decreased significantly by nanoparticles carrier. CONCLUSION: PLA-NPs might be used as a new oral carrier for triptolide.

Alanine Transaminase↗