2006 Vol. 19, No. 1

Select articles
Report on Childhood Obesity in China (2)Verification of BMI Classification Reference for Overweight and Obesity in Chinese Children and Adolescents
2006, 19(1): 1-7.
Objective To verify Working Group for Obesity in China (WGOC) recommended body mass index (BMI) classification reference for overweight and obesity in Chinese children and adolescents using the data of 2002 China Nationwide Nutrition and Health Survey. Methods Pediatric metabolic syndrome (MetS) and abnormality of each risk factor for MetS were defined using the criteria for US adolescents. Definition of hyper-TC, LDL, and dyslipidemia in adults was applied as well. The average level and abnormality rate of the metabolic indicators were described by BMI percentiles and compared with general linear model analysis. Receiver operating characteristic analysis was used to summarize the potential of BMI to discriminate between thepresence and absence of the abnormality of these indicators. Results There was neither significantly increasing nor significantly decreasing trend of biochemical parameter levels in low BMI percentile range (<65th). Slight increasing trend from the 75th and a significant increase were found when BMI≥85th percentile. In general, the prevalence of the examined risk factors varied slightly when BMI percentile<75th, and substantial increases were consistently seen when BMI percentile≥75th. As an indicator of hyper-TG, hypertension and MetS, the sensitivity and specificity were equal at the point of BMI<75th percentile, and the Youden's index of risk factors also reached peak point before 75th percentile except for MetS. When the BMI percentile was used as the screening indicator of MetS, Youden's index reached peak point at 85th percentile, just the point in the ROC graph that was nearest to the upper left corner. Conclusion The BMI classification reference for overweight and obesity recommended by WGOC is rational to predict and prevent health risks in Chinese children and adolescents. Lower screening cut-off points, such as 83th percentile or 80th percentile, should not be excluded when they are considered as overweight criteria in future intervention or prevention studies.
Metabolism of Terephthalic Acid and Its Effects on CYP4B1 Induction
2006, 19(1): 8-14.
Objective To investgate the metabolism of terephthalic acid (TPA) in rats and its mechanism. Methods Metabolism was evaluated by incubating sodium terephthalate (NaTPA) with rat normal liver microsomes, or with microsomes pretreated by phenobarbital sodium, or with 3-methycholanthrene, or with diet control following a NADPH-generating system. The determination was performed by high performance liquid chromatography (HPLC), and the mutagenic activation was analyzed by umu tester strain Salmonella typhimurium NM2009. Expression of CYP4B 1 mRNA was detected by RT-PCR. Results The amount of NaTPA (12.5-200 μmol· L-1) detected by HPLC did not decrease in microsomes induced by NADPH-generating system. Incubation of TPA (0.025-0.1 mmol·L-1) with induced or noninduced liver microsomes in an NM2009 umu response system did not show any mutagenic activation. TPA exposure increased the expression of CYP4B 1 mRNA in rat liver, kidney, and bladder. Conclusion Lack of metabolism of TPA in liver and negative genotoxic data from NM2009 study are consistent with other previous short-term tests, suggesting that the carcinogenesis in TPA feeding animals is not directly interfered with TPA itself and/or its metabolites.
Fenvalerate-induced Alterations in Calcium Homeostasis in Rat Ovary
2006, 19(1): 15-20.
Objective To observe the effects of fenvalerate on calcium homeostasis in rat ovary. Methods Female SpragueDawley rats were orally given fenvalerate at daily doses of 0.00, 1.91, 9.55, and 31.80 mg/kg for four weeks. The ovary ultrastucture was observed by electron microscopy. Serum free calcium concentration was measured by atomic absorption spectrophotometry. The activities of phosphorylase a in rat ovary were evaluated by the chromatometry. The total content of calmodulin in ovary was estimated by ELISA at each stage of estrous cycle. Radioimmunoassay (RIA) was used to evaluate the level of serum progesterone. Results Histopathologically, damages of ovarian corpus luteum cells were observed. An increase in serum free calcium concentration was observed in rats treated with 31.80mg/kg fenvalerate. The activities of phosphorylase a enhanced in all treated groups, and fenvalerate increased the total content of calmodulin significantly in estrus period. Serum progesterone levels declined in fenvalerate exposed rats in diestrus. Conclusion Fenvalerate interferes with calcium homeostasis in rat ovary. Also, the inhibitory effects of fenvalerate on serum progesterone levels may be mediated partly through calcium signals.
In vitro Cytotoxicity of TCDD on SPC-A1 Cells
2006, 19(1): 21-26.
Objective The toxicology of TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) has been studied mainly with regard to the carcinogenicity of its metabolites, but its phototoxicity is not well understood. Although some studies have indicated the lethal phototoxicity of TCDD, this study was designed to investigate its effect on SPC-A1 cells. Methods SPC-A1 cells were cultured in 1640 medium and treated with 10 nmol/L, 0.1 μmol/L, 1 μmol/L TCDD for either 24 h or 96 h at each concentration. SPC-A1 cells were co-cultured with TCDD at different concentrations. Then the cell morphology, DNA fragment electrophoresis, and cell cycle were analyzed by flow cytometry, and enzyme assays were used to observe the effect of TCDDon the morphology, growth rate, and enxyme change of SPC-A1 cells. Results With the increasing concentrations of TCDD and prolongation of culture time, the morphology of SPC-A1 cells was changed from round shape to spindle, and the ability of SPC-A1 cells to adhere to wall was decreased. With debris emitted around the cells, the morphologic changes included reduction in cell volume. Nuclear chromatin condensation and PI were observed. With the increasing concentrations of TCDD,DNA ladder occurred. After treatment with TCDD, extraction of cancer cells exhibited typical DNA fragmentation, and flow cytometry analysis showed apoptosis in a dose-dependent manner. As the concentration of TCDD rose from 10 nmol/L to 1 μmol/L, the ratio of apoptotic cells increased from 10.76% to 21.82%. Conclusions TCDD has in vitro cytotoxicity on SPC-A1 cells, and the cytotoxicity is positively related to its concentration and culture time. TCDD may inhibit the growth and proliferation of SPC-A 1 cells through the pathway of apoptosis introduction.
Tyrosine Hydroxylase as a Target for Deltamethrin in the Nigrostriatal Dopaminergic Pathway
2006, 19(1): 27-34.
Objective To study the effects of deltamethrin on tyrosine hydroxylase in nigrostriatum of male rats. Methods Sprague-Dawley rats were daily treated with deltamethrin at 6.25 or 12.5 mg/kg body weight by gavage for 10 days. Then HPLC-fluorescence detection was used to analyze the contents of dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC) and homoranillic acid (HVA) in substantial nigra and striatum. The activities of tyrosine hydroxylase (TH) were also detected by HPLC-fluorescence detection. TH mRNA or TH protein levels were measured by RT-PCR and immunohistochemistry method. Results The content of DA in striatum was significantly decreased by the treatments, suggesting an inhibition of DA synthesis by deltamethrin. The contents of DA metabolites DOPAC and HVA increased, indicating increased dopamine turnover. Furthermore, deltamethrin significantly decreased the activity, as well as the mRNA and protein levels of TH.Conclusions These findings reveal a novel aspect of deltamethrin neurotoxicity and suggest tyrosine hydroxylase as a molecular target of deltamethin on dopamine metabolism in the nigrostriatal pathway.
Inhibitory Effect of Isoflavones on Prostate Cancer Cells and PTEN Gene
2006, 19(1): 35-41.
Objective To explore the mechanisms by which genistein and daidzein inhibit the growth of prostate cancer cells. Methods LNCaP and PC-3 cells were exposed to genistein and daidzein and cell viability was determined by MTT assay and cytotoxicity of the drugs by LDH test. Flow cytometry (FCM) was used to assess the cell cycle in LNCaP and PC-3 cells.Reverse transcription-polymerase chain reaction (RT-PCR) was applied to examine the expression of PTEN gene (a tumor suppressor gene), estrogen receptor alpha gene (Erα), estrogen receptor beta gene (Erβ), androgen receptor gene (AR) and vascular endothelial growth factor gene (VEGF). Results The viability of PC-3 and LNCaP cells decreased with increasing concentrations and exposure time of genistein and daidzein. Genistein increased G2/M phase cells in PC-3 cells while decreased S phase cells in LNCaP cells in a dose-dependent manner. Daidzein exerted no influence on the cell cycle of LNCaP and PC-3 cells, but the apoptosis percentage of LNCaP cells was elevated significantly by daidzein. Genistein induced the expression of PTEN gene in PC-3 and LNCaP cells. Daidzein induced the expression of PTEN gene in LNCaP but not in PC-3 cells. The expression of VEGF, Erα and Erβ genes decreased and AR gene was not expressed after incubation with genistein and daidzein in PC-3 cells. In LNCaP cells, the expression of VEGF and AR gene decreased but there was no change in the expression of Erα and Erβ gene after incubation with genistein and daidzein. Conclusion Genistein and daidzein exert a time- and dose-dependent inhibitory effect on PC-3 and LNCaP cells. The down-regulation of ER gene by daidzein influences the growth of PC-3 cells directly. The inhibition of PC-3 cells by genistein and that of LNCaP cells by genistein and daidzein may be via Akt pathway that is repressed by PTEN gene, which subsequently down-regulates the expression of AR and VEGF genes. Our results suggest that the expression of PTEN gene plays a key role and several pathways may be involved in the suppression of prostate cancer cells by genistein and daidzein.
Comparison of Ileal Digested Production of Parental Rice and Rice Genetically Modified With Cowpeas Trypsin Inhibitor
2006, 19(1): 42-46.
Objective To compare the ileal digestibility of protein and amino acids in parental rice and rice genetically modified with sck gene. Methods Six experimental swines were surgically fixed with a simple T-cannula at the terminal ileum and fed with parental rice and rice genetically modified with sck gene alternately. The ileum digesta were collected and analyzed for determination of apparent and true digestibility of protein and amino acids. Results The apparent and true digestibility of protein was similar in these two types of rice. Except for the apparent digestibility of lysine, there was no difference in the apparent and true digestibility of the other 17 amino acids. Conclusion The digestibility of protein and amino acids is not changed by the insertion of foreign gene, so it can meet the request of "substantial equivalence" in digestibility of protein and amino acids.
Experimental Study on Denitrification Using Coated Electrode of Immobilized Denitrifying Bacteria
2006, 19(1): 47-52.
Objective To develop a coated electrode of immobilized denitrificants and to evaluate the performance of a bioelectrochemical reactor to enhance and control denitrification. Methods Denitrifying bacteria were developed by batch incubation and immobilized with polyvinyl alcohol (PVA) on the surface of activated carbon fiber (ACF) to make a coated electrode. Then the coated electrode (cathode) and graphite electrode (anode) were transferred to the reactor to reduce nitrate. Results After acclimated to the mixtrophic and autotrophic denitrification stages, the denitrifying bacteria could use hydrogen as an electron donor to reduce nitrate. When the initial nitrate concentration was 30.2 mg NO3--N/L, the denitrification efficiency was 57.3% at an applied electric current of 15 mA and a hydraulic retention time (HRT) of 12 hours.Correspondingly, the current density was 0.083 mA / cm2. The nitrate removal rate of the reactor was 34.4 g NO3--N / m3·d, and the surface area loading was 1.34 g NO3--N / m2·d. Conclusion The coated electrode may keep high quantity of biomass, thus achieving a high denitrification rate. Denitrification efficiencies are related to HRT, current density, oxidation reduction potential (ORP), dissolved oxygen (DO), pH value, and temperature.
Abnormal Expression of Eukaryotic Translation Factors in Malignant Transformed Human Bronchial Epithelial Cells Induced by Crystalline Nickel Sulfide
2006, 19(1): 53-60.
Objective To study the oncogenic potential of mouse translation initiation factor 3 (TIF3) and elongation factor-1δ (TEF-1δ) in malignant transformed human bronchial epithelial cells induced by crystalline nickel sulfide (NiS). Methods Abnormal expressions of human TIF3 and TEF-1δ genes in two kinds of NiS-transformed cells and NiS-tumorigenic cell lines were investigated and analyzed by the reverse transcript polymerase chain reaction (RT-PCR) and fluorescent quantitative polymerase chain reaction (FQ-PCR), respectively. Results RT-PCR analysis primarily showed that both human TIF3 and TEF-1δ mRNA expressions in two kinds of NiS-transformed cells and NiS-tumorigenic cell lines were increased as compared with controls. FQ-PCR assay showed that the levels of TIF3 expressions in the transformed cells and tumorigenic cells were 3 and 4 times higher respectively, and the elevated expressions of TEF-1δ cDNA copies were 2.7- to 3.5-fold in transformed cells and 4.1- to 5.2-fold in tumorigenic cells when compared with non-transformed cells, indicating that the over-expressions of human TIF3 and TEF-1δ genes were related to malignant degree of the cells induced by nickel. Conclusions These findings demonstrate that there are markedly abnormal expressions of TIF3 and TEF-1δ genes during malignant transformation of human bronchial epithelial cell lines induced by crystalline NiS. They seem to be the molecular mechanisms potentially responsible for human carcinogensis due to nickel.
Effect of α-Ketoglutarate on Cyanide-induced Biochemical Alterations in Rat Brain and Liver
2006, 19(1): 61-66.
Objective To investigate the biochemical changes in rat brain and liver following acute exposure to a lethal dose of cyanide, and its response to treatment of α-ketoglutarate (α-KG) in the absence or presence of sodium thiosulfate (STS). Methods Female rats were administered 2.0 LD50 potassium cyanide (KCN; oral) in the absence or presence of pre-treatment (-10 min), simultaneous treatment (0 min) or post-treatment (+2-3 min) of α-KG (2.0 g/kg, oral) and/or STS (1.0 g/kg,intraperitoneal, -15 min, 0 min or + 2-3 min). At the time of onset of signs and symptoms of KCN toxicity (2-4 min) and at the time of death (5-15 min), various parameters particularly akin to oxidative stress viz. Cytochrome oxidase (CYTOX),superoxide dismutase (SOD), glutathione peroxidase (GPx), reduced glutathione (GSH) and oxidized glutathione (GSSG) in brain, and CYTOX, sorbitol dehydrogenase (SDH), alkaline phosphatase (ALP), GSH and GSSG in liver homogenate were measured. Results At both time intervals brain CYTOX, SOD, GPx, and GSH significantly reduced (percent inhibition compared to control) to 24%, 56%, 77%, and 65%, and 44%, 46%, 78%, and 57%, respectively. At the corresponding time points liver CYTOX and GSH reduced to 74% and 63%, and 44% and 68%, respectively. The levels of GSSG in the brain and liver, and hepatic ALP and SDH were unchanged. Pre-treatment and simultaneous treatment of α-KG alone or with STS conferred significant protection on above variables. Post-treatment was effective in restoring the changes in liver but failed to normalize the changes in the brain. Conclusions Oral treatment with α-KG alone or in combination with STS has protective effects on cyanide-induced biochemical alterations in rat brain and liver.
Expression of c-fos in Rat Brain as a Prelude Marker of Central Nervous System Injury in Response to Methylmercury-stimulation
2006, 19(1): 67-72.
Objective To probe into the prelude marker of central nervous system injury in response to methyl mercury chloride (MMC) stimulation and the signal transduction molecular mechanism of injury in rat brain induced by MMC. Methods The expression of c-fos mRNA in brain and the expression of c-FOS protein in cortex, hippocampus and ependyma were observed using reverse transcription polymerase chain reaction (RT-PCR) and immunocytochemical methods. The control group was injected with physiological saline of 0.9%, while the concentrations for the exposure groups were 0.05 and 0.5,5 mg/kg MMC respectively, and the sampling times points were 20, 60, 240, 1440 min. Results The expression of c-FOS protein in cortex and hippocampus increased significantly, the accumulation of mercury in the brain induced by 0.05 mg/Kg MMC for 20 min had no significant difference compared with the control group. The mean value was 0.0044 mg/Kg, while the protein c-FOS expression had significant difference compared with the control group (P<0.01). More sensitive expression occurred in hippocampus and cortex, but not in ependyma. Conclusion The expression of c-FOS protein in cortex and hippocampus can predict the neurotoxicity of MMC in the early time, and immediately early gene (IEG) c-fos participates in the process of brain injury induced by MMC.
Anaerobic Degradation of Tetrachloroethylene Using Different Co-substrates as Electron Donors
2006, 19(1): 73-76.
Objective To investigate the biodegradation of tetrachloroethylene (PCE) by acclimated anaerobic sludge using different co-substrates, I.e., glucose, acetate, and lactate as electron donors. Methods HP-6890 gas chromatograph (GC) in combination with auto-sampler was used to analyze the concentration of PCE and its intermediates. Results PCE could be degraded by reductive dechlorination and the degradation reaction conformed to the first-order kinetic equation. The rate constants are k1actate>kglucose>kacetate. The PCE degradation rate was the highest in the presence of lactate as an electron donor.Conclusion Lactate is the most suitable electron donor for PCE degradation and the electron donors supplied by co-metabolic substrates are not the limiting factors for PCE degradation.
Biomedical and Environmental Sciences INFORMATION FOR AUTHORS
2006, 19(1)