Biomedical subjects

Ping Gong

Publications and source records attributed to Ping Gong.

At least 37 records · Page 2Linked to original sources

PubMed2005

Phytotoxicity of nitroaromatic energetic compounds freshly amended or weathered and aged in sandy loam soil.

The toxicities of 2,4,6-trinitrotoluene (TNT), 1,3,5-trinitrobenzene (TNB), 2,4-dinitrotoluene (2,4-DNT), and 2,6-dinitrotoluene (2,6-DNT) to terrestrial plants alfalfa (Medicago sativa L.), Japanese millet (Echinochloa crusgalli L.), and perennial ryegrass (Lolium perenne L.) were determined in Sassafras sandy loam soil using seedling emergence, fresh shoot, and dry mass measurement endpoints. A 13-week weathering and aging of energetic materials in soils, which included wetting and drying cycles, and exposure to sunlight of individual soil treatments, was incorporated into the study design to better reflect the soil exposure conditions in the field than toxicity determinations in freshly amended soils. Definitive toxicity tests showed that dinitrotoluenes were more phytotoxic for all plant species in freshly amended treatments based on EC20 values for dry shoot ranging from 3 to 24mgkg(-1) compared with values for TNB or TNT ranging from 43 to 62mgkg(-1). Weathering and aging of energetic materials (EMs) in soil significantly decreased the toxicity of TNT, TNB or 2,6-DNT to Japanese millet or ryegrass based on seedling emergence, but significantly increased the toxicity of all four EMs to all three plant species based on shoot growth. Exposure of the three plant species to relatively low concentrations of the four compounds initially stimulated plant growth before the onset of inhibition at greater concentrations (hormesis).

Benzene Derivatives↗

PubMed2005

[Platelet-rich plasma made by a modified method promotes proliferation of rat osteoblast and human osteoblast in vitro].

OBJECTIVE: To study the effect of serum rich in growth factors (SRGF) derived from platelet-rich plasma (PRP) on the biological function of human and rat osteoblast. METHODS: PRP and platelet-poor plasma (PPP) obtained from healthy human and SD rat were activated by thrombin to get SRGF and serum poor in growth factors (SPGF). The level of TGF-beta1 and PDGF-AB in human-SRGF and SPGF were assayed by enzyme-linked immunoassay (ELISA). Rat and human osteoblast were cultured and identified. Rat osteoblasts were treated with 5% rat-SRGF, 5% rat-SPGF and serum-free F12 medium, respectively. And human osteoblast were treated with 5% human-SRGF, 5% human-SPGF and serum-free DMEM. Cellular mitogenic activity was evaluated by thiazolyl blue (MTT) colorimetric assay at 24, 48, 72 and 96 hours. RESULTS: The level of TGF-beta1 in human-SRGF was 307.67 +/- 35.57 ng/ml, and that of PDGF-AB was 52.76 +/- 7.89 ng/ml. The proliferation of rat and human osteoblast were promoted after treated with rat-SRGF and human-SRGF, respectively. In rat osteoblast groups, there were significant differences in absorbency between rat-SPGF group and rat-SRGF group at 48 and 96 hours (P < 0.05). In human osteoblast groups, the differences between human-SPGF group and human-SRGF group were significant at 48, 72 and 96 hours (P < 0.05). The proliferation of these two kinds of osteoblasts almost stopped in serum-free medium, and the differences in absorbency, compared with other groups, were significant (P < 0.05). CONCLUSION: High quality of PRP can be achieved by the improved method and SRGF is capable of up-regulating the proliferation of rat osteoblast and human osteoblast.

Adolescent↗

PubMed2005

Effects of Jiantaiye on estrogen receptor and mRNA expressions in uterus of mice with embryo implantation dysfunction.

OBJECTIVE: To explore the effect of Jiantaiye (JTY) on the expression of estrogen receptor (ER) and ER mRNA in uterus of mice with embryo implantation dysfunction. METHODS: Embryo implantation dysfunction mouse models were induced with mifepristone and treated with JTY. All animals were sacrificed on day 8 of pregnancy. The endometrial ER and ER mRNA expressions were assessed by immunnohistochemical SP method and semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR). RESULTS: Area ratio and absorbency of ER in the JTY treated group's gland and stroma were higher than those of the model group, quite similar to those of the normal control's, and ER mRNA expression in treated group's uterus was significantly higher than that in the models, but it was not significantly different from the normal control. CONCLUSION: JTY improves the endometrial development by increasing ER and ER mRNA expressions of uterus of mice with embryo implantation dysfunction.

Animals↗

PubMed2005

Ecotoxicity of soils contaminated with industrial and domestic wastewater in western Shenyang, China.

Soil samples were collected from 7 sites in the up-, mid- and down-reach along and nearby the wastewater irrigation channel, western Shenyang of China. The concentrations of selected pollutants (mineral oil, PAHs--polycycle aromatic hydrocarbons and Cd) were determined by UV spectrometer, HPLC and AAS (atomic adsorption spectrometer) spectrometer, respectively. Toxicity effects of soils were evaluated by seedling emergence test with root length of wheat as the end-point and by earthworms test with the mortality rate and inhibition rates of body weight as endpoints. Results showed accumulation of pollutants for most soils with concentration of 200.2 mg x kg(-1)-1600 mg x kg(-1) for mineral oil, 0.33 mg x kg(-1)-1.81 mg x kg(-1) for Cd and 900.16 mg x kg(-1)-2737.91 mg x kg(-1) for PAHs. The inhibition rates of root elongation were from -20% up to 40%, and mortality rates of earthworms ranged from 0%-40% from the exposure period of two weeks to eight weeks by sampling interval of two weeks, the inhibition rates of earthworm growth were from -19.36% to 34.53%, showing effects of stimulation at 2 weeks to an increasing effects of inhibition at 4, 6 and 8 weeks, respectively. Mortality rates correlated with the loss of body weight of earthworms. This study indicated the potential risk of pollutants of environmental low content in soil by the determination of selected chemicals combined with toxicity indexes.

Animals↗

PubMed2005

Survival and reproduction of enchytraeid worms, Oligochaeta, in different soil types amended with energetic cyclic nitramines.

Hexanitrohexaazaisowurtzitane (CL-20), a new polycyclic polynitramine, has the same functional nitramine groups (N-NO2) as the widely used energetic chemicals hexahydro-1,3,5-trinitro-1,3,5-triazacyclohexane (royal demolition explosive [RDX]) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (high-melting explosive [HMX]). Potential impacts of CL-20 as an emerging contaminant must be assessed before its use. The effects of CL-20, RDX, or HMX on adult survival and juvenile production by potworms Enchytraeus albidus and Enchytraeus crypticus were studied in three soil types, including Sassafras sandy loam (1.2% organic matter [OM], 11% clay, pH 5.5), an agricultural soil (42% OM, 1% clay, pH 8.2), and a composite agricultural-forest soil (23% OM, 2% clay, pH 7.9) by using ISO method 16387 (International Standard Organization, Geneva, Switzerland). Results showed that CL-20 was toxic to E. crypticus with median lethal concentration values for adult survival ranging from 0.1 to 0.7 mg/kg dry mass (DM) when using the three tested soils. In addition, CL-20 adversely affected juvenile production by both species in all soils tested, with median effective concentration (EC50) values ranging from 0.08 to 0.62 mg/kg DM. Enchytraeus crypticus and E. albidus were similarly sensitive to CL-20 exposure in the composite agricultural-forest soil, which supported reproduction by both species and enabled comparisons. Correlation analysis showed weak or no relationship overall among the soil properties and reproduction toxicity endpoints. Neither RDX nor HMX affected (p > 0.05) adult survival of either species below 658 and 918 mg/kg DM, respectively, indicating that CL-20 is more toxic to enchytraeids than RDX or HMX. Examination of data shows that CL-20 should be considered as a potential reproductive toxicant to soil invertebrates, and that safeguards should be considered to minimize the potential for release of CL-20 into the environment.

Agriculture↗

PubMed2005

[Effects of jiantai liquid on the expression of estrogen/progesterone receptors in embryo implantation dysfunction mice endometrium].

OBJECTIVE: To explore the mechanism of Jiantai liquid on the endometrium development of embryo implantation dysfunction mice. METHOD: The model of embryo implantation dysfunction mice was induced by mifepristone and treated by Jiantai liquid. All animals were sacrificed on day 8 of pregnancy. Estradiol and progesterone concentrations in serum and endometrium tissue homogenates were measured by radioimmunoassay method, the endometial expressions of estrogen receptor (ER)and progesterone receptor (PR)assessed by immunohistochemical SP method. RESULT: There were no significantly differences in the estradiol and progesterone concentrations in serum and uterus tissue homogenates among three groups( P > 0.05). Absorbency and area rate of ER, PR in model group' s gland and stroma were higher than those in model group(P < 0.05), which was similar with the control group( P > 0.05). CONCLUSION: Jiantai liquid increase the implantation rate and improve the endometrial development by increasing the expressions of ER, PR in endometrium of embryo implantation dysfunction

Animals↗

PubMed2005

[Influence of basic fibroblast growth factors on the migration, proiferation of osteoblasts and periodontal ligament fibroblasts].

OBJECTIVE: In order to determine the influence of bFGF on the biological characteristics of osteoblasts and periodontal ligament cells, the author investigate the influence of bFGF on the migration, proliferation of osteoblasts and periodontal ligament fibroblasts between osteoblasts and fibroblasts. METHODS: The forth generation of osteoblasts and periodontal ligament fibroblast were obtained and the wounding model in vitro of them was founded. The cells were cultured in mediums with or without bFGF. Their migration and proliferation were observed and measured. RESULTS: Osteoblasts migrated faster than fibroblasts in common culture medium without bFGF and the periodontal ligament fibroblasts in culture medium with bFGF had higher migration rate than other groups. bFGF promoted the proliferation of both two kinds of cells. CONCLUSION: bFGF could accelerate periodontal fibroblasts' proliferation and migration.

Cell Proliferation↗

PubMed2005

Phytotoxicity assessment of phenanthrene, pyrene and their mixtures by a soil-based seedling emergence test.

Seedling emergence tests were conducted in a meadow brown soil using five plant species (i.e., Chinese cabbage, green onion, tomato, turnip and wheat) to determine the phytotoxicity of phenanthrene, pyrene and their mixtures. The soil was amended with up to 1000 mg/kg soil of phenanthrene or 600 mg/kg soil of pyrene. Seedling emergence and root growth were measured. The results indicated that root elongation was more sensitive than seedling emergence. Root length decreased with increasing phenanthrene or pyrene concentrations( p < or = 0.05). Phenanthrene was more phytotoxic than pyrene. The lowest observable adverse effect concentration (LOAEC) was 10 mg/kg for phenanthrene when tested with green onion, and 50 mg/kg for pyrene when tested with wheat. Among the five species, wheat was found to be the most sensitive. When amended jointly at or below their respective LOAEC, phenanthrene and pyrene produced a synergistic toxic effect.

Phenanthrenes↗

PubMed2004

Triple combination of irradiation, chemotherapy (pemetrexed), and VEGFR inhibition (SU5416) in human endothelial and tumor cells.

PURPOSE: This is the first preclinical report evaluating a trimodal therapy consisting of irradiation, chemotherapy, and antiangiogenesis in the context of a multimodal anticancer strategy. The combination of the folate antimetabolite pemetrexed, SU5416, a receptor tyrosine kinase inhibitor of VEGFR2, and irradiation was investigated in human endothelial cells and tumor cell lines. METHODS AND MATERIALS: Primary isolated human umbilical vein endothelial cells (HUVEC), human dermal microvascular endothelial cells (HDMEC), and human glioblastoma (U87) and prostate cancer cells (PC3) were exposed to pemetrexed (2 h) alone and in combination with SU5416 (2 h). When combined with irradiation up to 8 Gy, fixed concentrations of pemetrexed (1.06 muM) and SU5416 (1.0 muM) were used. Proliferation and clonogenic assays were conducted with endothelial and tumor cells. The migration/invasion ability of endothelial cells and the ability to produce tubular structures were tested in Matrigel and tube formation assays. Apoptosis was measured by sub-G1 DNA and caspase-3 flow cytometry. To investigate underlying cell signaling, immunocytochemistry was used to detect Akt survival signaling involvement. RESULTS: Triple combination using only a low-toxicity drug exposure of pemetrexed and SU5416 results in greater response than each treatment alone or than each combination of two modalities in all tested endothelial and tumor cell models. Triple combination substantially inhibits proliferation, migration/invasion, tube formation, and clonogenic survival. Triple combination also induced the highest rate of apoptosis in HDMEC and HUVEC as indicated by sub-1 G1 and caspase-3 assessment. Interestingly, triple combination therapy also reduces proliferation and clonogenic survival significantly in U87 and PC3 tumor cell lines. SU5416 potently inhibited Akt phosphorylation which could be induced by radiation and radiochemotherapy in human endothelial cells. CONCLUSIONS: Our findings demonstrate the high antiendothelial/antitumoral efficacy of the concurrent administration of irradiation, chemotherapy, and angiogenesis inhibition in vitro. A potential explanation for the favorable combination would be that VEGF signaling inhibition downregulates Akt survival signaling upon activation by radiation and/or chemotherapy. The data also suggest that endothelial cell apoptosis may have an important role in the benefits of the presented therapy.

Angiogenesis Inhibitors↗

PubMed2004

Preliminary ecotoxicological characterization of a new energetic substance, CL-20.

A new energetic substance hexanitrohexaazaisowurtzitane (or CL-20) was tested for its toxicities to various ecological receptors. CL-20 (epsilon-polymorph) was amended to soil or deionized water to construct concentration gradients. Results of Microtox (15-min contact) and 96-h algae growth inhibition tests indicate that CL-20 showed no adverse effects on the bioluminescence of marine bacteria Vibrio fischeri and the cell density of freshwater green algae Selenastrum capricornutum respectively, up to its water solubility (ca. 3.6 mg l(-1)). CL-20 and its possible biotransformation products did not inhibit seed germination and early seedling (16-19 d) growth of alfalfa (Medicago sativa) and perennial ryegrass (Lolium perenne) up to 10,000 mg kg(-1) in a Sassafras sandy loam soil (SSL). Indigenous soil microorganisms in SSL and a garden soil were exposed to CL-20 for one or two weeks before dehydrogenase activity (DHA) or potential nitrification activity (PNA) were assayed. Results indicate that up to 10,000 mg kg(-1) soil of CL-20 had no statistically significant effects on microbial communities measured as DHA or on the ammonium oxidizing bacteria determined as PNA in both soils. Data indicates that CL-20 was not acutely toxic to the species or microbial communities tested and that further studies are required to address the potential long-term environmental impact of CL-20 and its possible degradation products.

Analysis of Variance↗

PubMed2004

Toxicity assessment of contaminated soils from an antitank firing range.

Explosives are released into the environment at production and processing facilities, as well as through field use. These compounds may be toxic at relatively low concentrations to a number of ecological receptors. A toxicity assessment was carried out on soils from an explosive-contaminated site at a Canadian Forces Area Training Center. Toxicity studies on soil organisms using endpoints such as microbial processes (potential nitrification activity, dehydrogenase activity, substrate-induced respiration, basal respiration), plant seedling and growth (Lactuca sativa and Hordeum vulgare), and earthworm (Eisenia andrei) growth and reproduction were carried out. Results showed that 1,3,5,7-tetranitro-1,3,5,7-tetrazacyclooctane (HMX) was the principal polynitro-organic compound measured in soils. Soils from the contaminated site decreased microbial processes and earthworm reproduction; whereas plant growth was not significantly reduced. Toxicity to aquatic organisms and genotoxicity were also assessed on soil elutriates using Microtox (Vibrio fischeri), growth inhibition of algae (Selenastrum capricornutum), and SOS Chromotest (Escherichia coli). Results indicated that soil elutriates were generally not toxic to bacteria (Microtox) and algae. However, genotoxicity was found in a number of soil elutriate samples. Thus, the explosive-contaminated soils from the antitank firing range may represent a hazard for the soil organisms. Nevertheless, the global toxicity might have partially resulted from HMX as well as from other (not identified) contaminants such as heavy metals.

Animals↗

PubMed2004

Computed tomography monitoring of radiation-induced lung fibrosis in mice.

RATIONALE AND OBJECTIVES: To identify characteristics of lung fibrosis in a mouse model after radiotherapy (RT) using thin-section computed tomography (CT), histology and clinical parameters. MATERIALS AND METHOD: Using a multislice CT-scanner, follow-up chest CT scans of 10 out of 72 included mice (C57BL/6J, 36 control mice, 36 mice (20Gy)) were performed every 2 weeks until week 26 after RT. Hounsfield units (HU) and cardiothoracic ratio (CTR) were measured, and a multireader analysis on characteristic lung changes was performed and correlated with histology and clinical parameters. RESULTS: From weeks 4 to 8 after RT changes in histology (leukocyte count, extraalveolar edema, P < 0.01) and from week 12 changes in CT were detected (increase in HU, intralobular opacity and fibrotic strandings, P < 0.05). From week 14 clinical manifestations occurred (loss of weight, mobility, breathing, increased mortality, P < 0.01). CTR showed no significant changes. Three readers showed excellent interobserver agreement (kappa >0.84). CONCLUSION: Thin-section CT in a mouse model is capable of detecting the development of lung fibrosis after RT prior to the onset of clinical deterioration.

Animals↗

PubMed2004

Acute and chronic toxicity of the new explosive CL-20 to the earthworm (Eisenia andrei) exposed to amended natural soils.

Monocyclic nitramine explosives such as 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) are toxic to a number of ecological receptors, including earthworms. The polycyclic nitramine CL-20 (2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane) is a powerful explosive that may replace RDX and HMX, but its toxicity is not known. In the present study, the lethal and sublethal toxicities of CL-20 to the earthworm (Eisenia andrei) are evaluated. Two natural soils, a natural sandy forest soil (designated RacFor2002) taken in the Montreal area (QC, Canada; 20% organic carbon, pH 7.2) and a Sassafras sandy loam soil (SSL) taken on the property of U.S. Army Aberdeen Proving Ground (Edgewood, MD, USA; 0.33% organic carbon, pH 5.1), were used. Results showed that CL-20 was not lethal at concentrations of 125 mg/kg or less in the RacFor2002 soil but was lethal at concentrations of 90.7 mg/kg or greater in the SSL soil. Effects on the reproduction parameters such as a decrease in the number of juveniles after 56 d of exposure were observed at the initial CL-20 concentration of 1.6 mg/kg or greater in the RacFor2002 soil, compared to 0.2 mg/kg or greater in the SSL soil. Moreover, low concentrations of CL-20 in SSL soil (approximately 0.1 mg/kg; nominal concentration) were found to reduce the fertility of earthworms. Taken together, the present results show that CL-20 is a reproductive toxicant to the earthworm, with lethal effects at higher concentrations. Its toxicity can be decreased in soils favoring CL-20 adsorption (high organic carbon content).

Adsorption↗

PubMed2004

[Interaction between osteoblasts and fibroblasts derived from same individual].

OBJECTIVE: In order to determine the effect of factors pertaining to the development and metabolism of periodontal ligament, the author investigated the interaction between osteoblasts and fibroblasts. METHODS: The cell co-culture model was established by cell culture inserts. The expression difference of protein related to mineralization (ALP, Type I collagen) between these two kinds of cells cultured individually and co-cultured were evaluated. RESULTS: Co-culture changed the ALPase activity of the two kinds of cells greatly .The ALP expression of osteoblasts decreased, but the ALP expression of periodontal ligament fibroblasts increased. The Col-I expression of these two kinds of cells did not change significantly when they were co-cultured. CONCLUSION: Periodontal ligament fibroblast could restrain the osteogenesis function of osteoblast, while osteoblast could induce the differentiation of fibroblast when both of them existed in periodontal tissue.

Alkaline Phosphatase↗

PubMed2004

[Effect of jiantai liquid on expression of estrogen and progesterone receptors in uterus of mice with embryo implantation dysfunction induced by mifepristone].

OBJECTIVE: To explore the molecular mechanism of jiantai liquid (JTL) in improving endometrial receptivity of mice with embryo implantation dysfunction (EID). METHODS: Mice model of EID induced by mifepristone were intervened with JTL (Twig of Chinese Taxillus, Red Sage root, Chinese Angelica, Milkvetch root, Chuanxiong rhizome), and sacrificed on day 8 of pregnancy. The endometrial estrogen receptor (ER) and progesterone receptor (PR) protein and their gene expressions were assessed by Western blot and semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR). RESULTS: Levels of ER and PR protein and their gene expressions in the JTL treated group were significantly higher than those in the model group respectively (all P < 0.05), and showed insignificant difference from those in the normal control group (all P > 0.05). CONCLUSION: JTL could promote the development of endometrium and improve the embryo implantation by way of regulating the levels of ER and PR protein and gene expression in mice with EID.

Animals↗

PubMed2004

[Analysis of plasmid pUDKH by anion-exchange high performance liquid chromatogaphy].

pUDKH, a new plasmid DNA comprising human hepatocyte growth factor (HGF), was developed as a potential genetherapeutic product for peripheral arterial disease. An anion-exchange high performance liquid chromatographic (HPLC) method was developed to determine the proportion of plasmid DNA in both opened and supercoiled forms. A TSK gel DNA-NPR column was equilibrated with 50% buffer A (20 mmol/L Tris-HCl, pH 8.8) and 50% buffer B (buffer A with 1 mol/L NaCl added). pUDKH was analyzed by using a gradient HPLC with a mobile phase from 50% B to 80% B and with a UV detection at 260 nm. The flow rate was 0.5 mL/min. The method was also used to monitor the production procedures.

Chromatography, High Pressure Liquid↗

PubMed2003

Genotoxicity of 2,4- and 2,6-dinitrotoluene as measured by the Tradescantia micronucleus (Trad-MCN) bioassay.

The phytogenotoxicity of 2,4-dinitrotoluene (2,4-DNT) and 2,6-dinitrotoluene (2,6-DNT) was assessed using the Tradescantia micronucleus (Trad-MCN) bioassay. Tradescantia cuttings bearing young inflorescences were exposed for 6h to 2,4- or 2,6-DNT amended water solutions up to their respective solubilities. The nominal concentrations were 0, 1.9, 3.8, 7.5, 15, 30, 60, 100, 150, 200mg/l of 2,4-DNT, and 0, 7.5, 15, 30, 60, 90, 120, 180mg/l of 2,6-DNT. Each treatment was repeated three or four times. Chemical concentrations in test solutions were analyzed prior to and after the exposure. Cadmium chloride (0-20mM) was used as the positive control. Micronuclei (MCN) were scored in the tetrad-stage pollen mother cells. The MCN frequency (%), i.e. the number of micronuclei scored in 100 tetrads, was the measurement endpoint. Results indicated that both 2,4-DNT and 2,6-DNT were genotoxic with the minimum effective dose (MED) of 30 and 135mg/l, respectively. Longer exposure (30h) without recovery time at 150mg/l of 2,4-DNT and 180mg/l of 2,6-DNT did not induce significantly higher MCN frequencies.

Air Pollutants, Occupational↗

PubMed2003

Purification, N-terminal sequencing, partial characterization, crystallization and preliminary crystallographic analysis of two glycosylated serine proteinases from Agkistrodon acutus venom.

AaV-SP-I and AaV-SP-II, two glycosylated serine proteinases from Agkistrodon acutus venom with fibrinogenolysis and esterolysis activities, have been purified to homogeneity by three-step ion-exchange chromatography. Estimated by SDS-PAGE, the molecular weights of AaV-SP-I and AaV-SP-II are about 32 and 31 kDa under reducing conditions and 26 and 25 kDa under non-reducing conditions, respectively. The first 24 N-terminal amino-acid residues are the same in both sequences and display a high homology with those of several snake-venom serine proteinases. However, the proteins possess obviously distinct carbohydrate contents. Using the conventional hanging-drop vapour-diffusion method, single crystals of both enzymes were grown that were suitable for X-ray diffraction analysis. The crystals of AaV-SP-I and AaV-SP-II belong to space groups P2(1)2(1)2(1) and C2, respectively. In each case there is only one molecule in the asymmetric unit.

Agkistrodon↗