In order to use facultative gut bacteria as an alternate to animals for the initial gastrointestinal toxicity screening of heavy metals, a comparative study on rat intestinal epithelial cells and resident gut bacteria was undertaken.Methods in vitro growth rate of four gut bacteria, dehydrogenase (DHA) and esterase (EA) activity test, intestinal epithelial and bacterial cell membrane enzymes and in situ effect of arsenite were analysed. Results Growth profile of mixed resident population of gut bacteria and pure isolates of Escherichia coli, Pseudomonas sp., Lactobacillus sp., and Staphylococcus sp.revealed an arsenite (2-20 ppm) concentration-dependent inhibition. The viability pattern of epithelial cells also showed similar changes. DHA and EA tests revealed significant inhibition (40%-72%) with arsenite exposure of 5 and 10 ppm in isolated gut bacteria and epithelial cells. Decrease in membrane alkaline phosphatase and Ca2+-Mg2+-ATPase activities was in the range of 33%-55% in four bacteria at the arsenite exposure of 10 ppm, whereas it was 60%-65% in intestinal epithelial villus cells. in situ incubation of arsenite using intestinal loops also showed more or less similar changes in membrane enzymes of resident gut bacterial population and epithelial cells. Conclusion The results indicate that facultative gut bacteria can be used as suitable in vitro model for the preliminary screening of arsenical gastrointestinal cytotoxic effects.
To develop a safe and novel immunoadjuvant to enhance the immunity and resistance of animals against E.coli infection. Methods An 88-base immunostimulatory oligodeoxynuleotide containing eleven CpG motifs (CpG ODN)was synthesized and amplified by PCR. The chitosan nanoparticle (CNP) was prepared by ion linking method to entrap the CpG ODN that significantly promotes the proliferation of lymphocytes of pig in vitro. Then the CpG- CNP was inoculated into 21-day old Kunming mice, which were orally challenged with virulent K88/K99 E. Coli 35 days after inoculation. Blood was collected from the tail vein of mice on days 0, 7, 14, 21, 28, 35, 42, and 49 after inoculation to detect the changes and content of immunoglobulins, cytokines and immune cells by ELISA, such as IgG, IgA, IgM, IL-2, IL-4, and IL-6. Results The CpG provoked remarkable proliferation of lymphocytes of pig in vitro in comparison with that of control group (P＜0.05). The inoculation with CpG-CNP significantly raised the content of IgG, IgM, and IgA in the sera of immunized mice (P＜0.05). The levels of IL-2, IL-4, and IL-6 in the mice significantly increased in comparison with those in controls (P＜0.05), so was the number of white blood cells and lymphocytes in immunized mice. The humoral and cellular immunities were significantly enhanced in immunized mice, which resisted the infection of E. coli and survived, while the control mice manifested evident symptoms and lesions of infection. Conclusions CpG-CNP can significantly promote cellular and humoral immunity and resistance of mice against E. coli infection, and can be utilized as an effective adjuvant to improve the immunoprotection and resistance of porcine against infectious disease.
To evaluate the acute toxicity of 2-deoxy-D-glucose (2DG) by oral (p.o.) and intravenous (i.v.) routes, and also the cardio-respiratory effects following high doses of 2DG in animal models. Methods The LD50 of 2DG (in water)was determined in rats and mice by p.o. route and in mice by i.v. route. The effect of 2-DG (250 mg/kg, 500 mg/kg, and 1000mg/kg, i.v.) was studied on various cardio-respiratory parameters viz., mean arterial blood pressure, heart rate and respiratory rate in anaesthetised rats. The effect of 2DG (500 mg/kg, 1000 mg/kg, and 2000 mg/kg, p.o.) was also studied on various respiratory parameters viz., respiratory rate and tidal volume in conscious rats and mice using a computer program. Results The p.o. LD50 of 2DG was found to be ＞8000 mg/kg in mice and rats, and at this dose no death was observed. The LD50 in mice by i.v. route was found to be 8000 mg/kg. At this dose 2 out of 4 mice died and the death occurred within 6 h. A significant increase in the body weight was observed after p.o. administration of 2DG in rats at 500 mg/kg, 1000 mg/kg, and 2000 mg/kg doses. There was no significant change in the body weight at 4000 mg/kg and 8000 mg/kg by the p.o. route in rats and up to 8000 mg/kg by p.o. as well as i.v. routes in mice. Intravenous administration of 2DG (250 mg/kg, 500 mg/kg, and 1000 mg/kg)in anaesthetised rats showed a time-dependent decrease in the mean arterial blood pressure. There was no change in the heart rate in any of the treatment groups. The tidal volume was not changed significantly by p.o administration in conscious rats, but a significant decrease in the respiratory frequency at 500 mg/kg and 1000 mg/kg doses was observed. In the mice also there was no change in the tidal volume after p.o, administration, but the respiratory frequency decreased significantly at 2000 mg/kg dose.Conclusion 2DG is a safe compound but can cause a fall in the blood pressure and a decrease in respiratory frequency at high doses.
To study the gene expression of metallothionein 1 (MT-1) isoforms in human peripheral blood lymphocytes (HPBLs). Methods The expression of mRNA representing the seven active MT-1 genes was determined in HPBLs by quantitative RT-PCR before and after exposure to cadmium. Results Basal expressions of MT-1X, and MT-1A in HPBLs were similar to expression of housekeeping gene. In contrast, the basal gene expressions of MT-1H, 1F, 1E, and 1G were a little transcripts in human HPBLs. No signal was detected for MT-1B. There was a sex difference (P＜0.05). in basal gene expression of MT-1E. The levels of gene expression of MT-1A, 1E, 1F, 1G, 1H, and 1X increased, but the level of MT-1B did not increase after exposure to cadmium. Conclusions Gene expressions of MT-1G, MT-1H, MT-1F, and MT-1X in HPBLs can be used as a potential biomarker of cadmium exposure.
To assess the health safety of copper, steel and plastic water pipes by field water quality investigations.Methods Four consumers were randomly selected for each type of water pipes. Two consumers of every type of the water pipes had used the water pipes for more than 1 year and the other 2 consumers had used the water pipes for less than 3 months.The terminal volume of tap water in copper and steel water pipes should be not less than 0.1 liter, whereas that in plastic water pipes should be not less than 1 liter. Results The mean values of the experimental results in the second field water quality investigation of the copper and steel water pipes met the Sanitary Standards for Drinking Water Quality. The items of water sample of the plastic water pipes met the requirements of the Sanitary Standards for Drinking Water Quality. Conclusion Copper, steel, and plastic pipes can be used as drinking water pipes.
To study the effects and the mechanisms of extract from a leguminous plant (Ammopiptanthus mongolicus cheng f.) (JA1) in northwest China on inducing apoptosis and inhibiting proliferation of HepG2 hepatocarcinoma cell in vitro.Methods The HepG2 cell line was used as target cells. The effect of JA 1 on HepG2 cell growth was detected by microculture tetrazolium assay (MTT), flow cytometry assay, DNA agarose gel electrophoresis and transmission electronic microscopy. The expressive effect of the wt-p53 in HepG2 cells was analyzed with p53 protein test-reagent. Results JA1 not only had significant anti-proliferative effects depending upon time and dosage, but also induced apoptosis of HepG2 cells. Apoptotic typical morphological changes were observed in JA1-treated HepG2 cells under transmission electronic microscope, "Sub-Gl"phase peak occurred in flow cytometry and DNA "ladder" was found in DNA agarose gel electrophoresis. The expression of the wt-p53 increased in vitro, and JA1-treated HepG2 and the positive cell percentage of the wt-p53 protein also increased.Conclusions JA1 could obviously induce apoptosis and inhibit proliferation of HepG2 cells in vitro, and these effects are closely related with the increase of wt-p53 expression. JA1 can be used as a good source of medicinal plant for the treatment of hepatocarcinoma.
To evaluate the alterations of biomarkers in the development and progression of coal workers'pneumoconiosis (CWP). Methods The type and number of cells, and the levels of tumor necrosis factor-alpha (TNF-α),pulmonary surfactant protein, phospholipids and fibronectin in bronchoalveolar lavage fluid were assayed in 14 health active coal miners, 21 coal miners without CWP and 13 miners with CWP of 0/1 to 1/1. Results Compared to active coal miners without CWP (8.23 μg/mL), TNF-α concentration was gradually decreased when dust exposure was stopped (5.90 μg/mL).Elevated surfactant protein A (SP-A) level and phosphatidylglycerol (PG) to phosphatidylinositol (PI) ratio were found in miners actively exposed to coal dust (6528 ng/mL for SP-A and 10. for PG/PI), and both parameters decreased when CWP progressed from CWP (0/1) (3419 μg/mL for SP-A and 5.9 for PG/PI) to CWP (1/1) (1654 μg/mL for SP-A and 5.5 for PG/PI).Conclusion Biomarkers in bronchoalveolar lavage fluid can be used to screen coal miners at high risk of developing coal workers' pneumoconiosis.
To study the relationship of remote sensing normalized differential vegetation index (NDVI) to Anopheles density and malaria incidence rate. Methods Data of monthly average climate, environment, Anopheles density and malaria incidence rate, and remote sensing NDVI were collected from 27 townships of 10 counties in southeastern Yunnan Province from 1984 to 1993. The relationship of remote sensing ecological proxy index, NDVI, to Anopheles density and malaria incidence rate was studied by principal component analysis, factor analysis and grey correlation analysis. Results The correlation matrix showed that NDVI highly correlated with Anopheles density in 4 townships of Mengla, Jinghong, and Yuanjiang counties, but in other 23 townships the relationship was not clear. Principal component and factor analyses showed that remote sensing NDVI was the representative index of the first principal component and the first common factor of Anopheles density evaluation. Grey correlation analysis showed that in rainy season NDVI had a high grey correlation with Anopheles density and malaria incidence rate. The grey correlation analysis showed that in rainy season the grey degree of NDVI correlated with Anopheles. Minimus density was 0.730, and 0.713 with Anopheles sinensis density, and 0.800 with malarial incidence rate. Conclusion Remote sensing NDVI can serve as a sensitive evaluation index of Anopheles density and malaria incidence rate.
To determine whether -238G/A and -857C/T polymorphisms of tumor necrosis factor-alpha (TNF-α) gene promoter were associated with outcomes of hepatitis B virus infection. Methods A total of 246 HBV self-limited infected subjects and 443 chronic hepatitis B (HB) patients were recruited in this case-control study. TNF-α-238G/A and -857C/T gene promoter polymorphisms were examined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).Results The frequency of TNF-α-238 GG (90.7%) in chronic HB group was significantly lower than that (95.1%) in self-limited group (P=0.041). The frequency of TNF-α-857 CC (79.7%) in chronic HB patients was significantly higher than that (70.9%) in self-limited infected subjects (P=0.021). Multiple logistic regression analysis revealed that both TNF-α-238GA and -857CC were independently associated with chronic HB. Conclusions TNF-α promoter variants are likely to play a substantial role in influencing the outcomes of HBV infection.
To evaluate the environmental quality of Guiyu, Guangdong impacted by the electronic waste recycling industry. Methods The surface water, ground water and sediment samples taken separately from two sites that recycle E-wastes and other rubbish relevant to the E-waste recycling, and an agricultural area, were analyzed, and the data were used to evaluate the impact of E-waste recycling on the environmental quality of Guiyu based on environmental quality standards in China. Results The concentrations of lead and iron in the surface water samples significantly different in the three locations. The maximum value of lead in the first site was 8 times higher than the threshold of environmental quality standards for surface water. The concentration of iron in polluted sample was 22 times that of the background sample. Manganese and iron also showed a significant difference in ground water samples between the three sites. The amount of iron was 22 times that of the threshold of the quality standard for ground water, and 120 times that of the background sample. Moreover, the results of all the eight heavy metals showed significant differences among the sediment samples. The concentrations of copper, cadmium,nickel, and lead in the polluted samples were above the median benchmarks of National Oceanic and Atmospheric Administration (NOAA). The copper concentration of 2670 mg/kg was 10 times that of the median benchmark. ConclusionE-waste recycling has led to the severe pollution Guiyu.
To study the protective effect of volatile anesthetics, isoflurane and sevoflurane, on ischemic neurons after cerebral ischemia-reperfusion in rats and its possible molecular mechanism. Methods Rat cerebral ischemia-reperfusion model was developed by occlusion of the middle cerebral artery (MCA) and bilateral common carotid arteries (CCAs) 1 h after reperfusion. Using flow cytometry (FCM) and Northern blot hybridization, we calculated the number of apoptotic bodies and detected the expression of bcl-2 mRNA and interleukin-1 β converting enzyme (ICE) mRNA. Results The apoptotic bodies in hippocampus analyzed by FCM peaked at appeared 24 h after reperfusion, and decreased about 54% and 40%, respectively,after treatment with isoflurane and sevoflurane, as compared with ischemic group. There was no significant difference in the expression of bcl-2 mRNA and ICE mRNA between the inhaled anesthetic groups and ischemic group in hippocampus 24 hafter MCA/CCAs occlusion. Conclusion Isoflurane and sevoflurane partially inhibit apoptosis but have no significant effect on the expression of bcl-2 and ICE genes.
To study the preparation of seeding type immobilized microorganisms and their degradation characteristics on di-n-butyl phthalate (DBP). Methods Diatomite, clinoptilolite, silk zeolite, and coal fly ash were chosen as reserved materials and modified. Their adsorption capacity and intensity in the bacteria were determined and the best carrier was picked out. The seeding type immobilized microorganisms were prepared by the best carrier and then it degraded DBP under different primary concentration, vibration rate, pH, temperature in the presence of metal compounds. Results The adsorption capacity of the modified coal fly ash, silk zeolite, clinoptilolite and zeolite was 44.2%, 71.6%, 84.0%, and 94.4%, respectively, which was 1.66, 1.49, 1.37, and 1.16 times as high as that of their natural state. Their adsorption intensity was 72.1%, 90.5%, 90.1%,and 91.1% in turn. The modified diatomite was selected to prepare the seeding type immobilized microorganisms. When the primary DBP concentration was 100 to 500 mg/L, the DBP-degraded rate of the immobilized microorganisms could be above 80%. The degradation activity of both the dissociative and immobilized microorganisms was higher in vibration than in stillness.When pH was 6.0 to 9.0, the DBP-degraded rate of the immobilized microorganisms was above 82%, which was higher than the dissociative microorganisms. When the temperature was between 20℃ and 40℃, the DBP-degraded rate could reach 84.5% in 24 h. The metal compounds could inhibit the degradation activity of both the dissociative and immobilized microorganisms. The degradation process of the immobilized microorganisms could be described by the first-order model.Conclusion The adsorption capacity of the diatomite, clinoptilolite, silk zeolite and coal fly ash on DBP-degrading bacteria can be improved obviously after they are modified. The modified diatomite is best in terms of its adsorption capacity and intensity. Its seeding type immobilized microorganisms could degrade DBP effectively and is more adaptable to DBP load,temperature, pH than the dissociative microorganisms. The metal compounds could inhibit the activity of both the immobilized and dissociative microorganisms. The degradation reaction of the immobilized microorganisms on DBP is consistent with the first-order model.
To investigate the epidemiological characteristics of human papillomavirus (HPV) infection in men attending a sexually transmitted diseases (STD) clinic in Hangzhou area. Methods Male subjects (n=375) aged 18-70 years,attending the STD clinic were recruited. Urethral swabs were assessed for HPV DNA using polymerase chain reaction (PCR)with the consensus primers MY09/11. HPV genotypes of positive PCR products were determined by restriction fragment length polymorphisms and direct sequence analysis. Results Of the 375 swabs collected, 305 (81.3%) yielded sufficient DNA for the subsequent HPV analysis. Among the 305 subjects, the prevalence of HPV was 13.8%. Nononcogenic HPV types were found in 8.5% (26/305) of subjects, oncogenic types in 4.3% (13/305), and multiple types in 1.0% (3/305). The prevalence of HPV infection was higher in subjects from urban area than in those from rural area (P＜0.05). The prevalence was also higher in those who received fewer years of education (P＜0.05) and those who had more sex partners (P＜0.05). Conclusions HPV infection among men at high risk is not uncommon. The detection rate of HPV DNA is significantly related to some sociodemographic factors, such as residence, educational level and the number of sex partners.