2008 Vol. 21, No. 5

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Isoflavone Regulates Lipid Metabolism via Expression of Related Genes in OVX Rats Fed on a High-fat Diet
2008, 21(5): 357-364.
Objective To investigate the effects of isoflavone on body weight, fat mass, and gene expression in relation to lipid metabolism. Methods Thirty-six female SD rats were variectomized or sham-operated and fed on a high-fat diet. Two months later, abdominal incision was made, blood was collected to separate serum, and the liver and adipose tissue were immediately collected and weighed. Some portions of these tissues were frozen in liquid nitrogen and stored at -80℃. Results Ovariectomy (OVX) with a high-fat diet could induce obesity in rats, while treatment with isoflavone significantly inhibited the increase in body weight and fat mass in abdomen. Serum total cholesterol and leptin were significantly decreased in isoflavone group, compared with the OVX group. The mRNA expression of liver fatty acid synthase (FAS) in the OVX group was significantly higher than that in sham-operated group, while this difference was not observed in the isoflavone group. The mRNA expression of liver hormone-sensitive lipase (HSL) in the OVX rats tended to be lower than that in the sham-operated rats. Furthermore, a large amount of isoflavone maintained the mRNA expression at a sham level. Conclusion lsoflavone may prevent obesity induced by ovariectomy with a high-fat diet, in part by modulating gene expression related to lipid metabolism.
Antagonistic Potential against Pathogenic Microorganisms and Hydrogen Peroxide Production of Indigenous Lactobacilli Isolated from Vagina of Chinese Pregnant Women
2008, 21(5): 365-371.
Objective To investigate the indigenous lactobacilli from the vagina of pregnant women and to screen the isolates with antagonistic potential against pathogenic microorganisms. Methods The strains were isolated from pregnant women's vagina and identified using the APISOCH system. The ability of the isolates to produce hydrogen peroxide was analyzed semi-quantitatively using the TMB-HRP-MRS agar. The antagonistic effects of the isolates on pathogenic microorganisms were determined with a double layer agar plate. Results One hundred and three lactobacilli strains were isolated from 60 samples of vaginal secretion from healthy pregnant women. Among them, 78 strains could produce hydrogen peroxide, in which 68%, 80%, 80%, and 88% had antagonistic effects against Candida albicans CMCC98001, Staphylococcus aureus CMCC26003, Escherichia coli CMCC44113, and Pseudomonas aeruginosa CMCC10110, respectively. Conclusion The recovery of hydrogen peroxide-producing lactobacilli decreases with the increasing pregnant age and time. The most commonly isolated species from vagina of Chinese pregnant women are Lactobacillus acidophilus and Lactobacillus crispatus. Most of L. Acidophilus and L. Crispatus produce a high H2O2 level.
Recombinant Human IgG antibodies against Human Cytomegalovirus
2008, 21(5): 372-380.
Objective To study the passive immunization with human monoclonal antibodies as for prophylaxis of human eytomegalovirus (HCMV) infection. Methods Fab monochinal antibodies to HCMV were recovered by repertoire cloning of mRNA from a HCMV infected individual. Antigen binding specificity, CDR sequence of Vhand Vland neutralizing activity on HCMV AD169 stain were analyzed in vitro. The light and heavy chain Fd fragment genes of Fab antibodies were further cloned into a recombinant baculovirus expression vector pAC-κ-Fc to express intact IgG. Secreted products were purified with affinity chromatography using protein G. Results SDS-PAGE and Western blot confirmed the expression of the intact IgG. Immuno-blotting and -precipitation were used to identify HCMV proteins. One Fab monoclonal antibodyrecognized a conformational HCMV protein. Conclusion IgG antibodies can neutralize the HCMV AD169 strain efficiently at a titer of 2.5 μg/mL and may prove valuable for passive immunoprophylaxis against HCMV infection in humans.
Bioassay of Estrogenic Activity of Effluent and Influent in a Farm Wastewater Treatment Plant Using an in vitro Recombinant Assay with Yeast Cells
2008, 21(5): 381-388.
Objective Environmental estrogens at an elevated concentration are known to produce adverse effects on human and animal life. However, the majority of researches have been focused on ndustrial discharges, while the impact of livestock wastes as a source of endocrine disrupters in aquatic environments has been rarely elucidated. In order to investigate the contribution of environmental estrogens from livestock, the estrogenic activity in water samples from a farm wastewater treatment plant was analyzed by a recombinant yeast screening method. Methods The extracts prepared from 15 selected water samples from the farm wastewater treatment plant, among which 6 samples were from pre-treatment section (influents) and 9 from post-treatment section (effluents), were analyzed for estrogenic activity by cellar bioassay. Yeast cells transfected with the expression plasmid of human estrogen receptor and the Lac Z reporter plasmid encoding β-galactossidase, were used to measure the estrogen-like compounds in the farm wastewater treatment plant. Results The wastewater samples from influents showed a higher estrogenic potency than the effluent samples showing a low induction of β-galactossidase relative to solvent control condition. By comparison with a standard curve for 1713-estradiol (E2), estrogenic potency in water samples from the influents was calculated as E2-equivalent and ranged from 0.1 to 150 pM E2-equivalent. The estrogenic potency in water samples from the effluents was significantly lower than that in the influents, and 7 water samples had less detectable limit in the total of 9 samples. Conclusion Yeast bioassay of estrogenic activity in most of the samples from the farm wastewater after disposal by traditional sewage treatment showed negative results.
Non-Fusion and Fusion Expression of β-Galactosidase from Lactobacillus bulgaricus in Lactococcus lactis
2008, 21(5): 389-397.
Objective To construct four recombinant Lactococcus lactis strains exhibiting high β-galactosidase activity in fusion or non-fusion ways, and to study the influence factors for their protein expression and secretion. Methods The gene fragments encoding β-galactosidase from two strains of Lactobacillus bulgaricus, wch9901 isolated from yogurt and 1.1480 purchased from the Chinese Academy of Sciences, were amplified and inserted into lactococcal expression vector pMG36e. For fusion expression, the open reading frame of the β-galactosidase gene was amplified, while for non-fusion expression, the open reading frame of the β-galactosidase gene was amplified with its native Shine-Dalgarno sequence upstream. The start codon of the β-galactosidase gene partially overlapped with the stop codon of vector origin open reading frame. Then, the recombinant plasmids were transformed into Escherichia coli DH5α and Lactococcus lactis subsp, lactis MG1363 and confirmed by determining β-galactosidase activities. Results The non-fusion expression plasmids showed a significantly higher β-galactosidase activity in transformed strains than the fusion expression plasmids. The highest enzyme activity was observed in Lactococcus lactis transformed with the non-fusion expression plasmids which were inserted into the β-galactosidase gene from Lactobacillus bulgaricus wch9901. The β-galactosidase activity was 2.75 times as high as that of the native counterpart. In addition, β-galactosidase expressed by recombinant plasmids in Lactococcus lactis could be secreted into the culture medium. The highest secretion rate (27.1%) was observed when the culture medium contained 20 g/L of lactose. Conclusion Different properties of the native bacteria may have some effects on the protein expression of recombinant plasmids. Non-fusion expression shows a higher enzyme activity in host bacteria. There may be a ost-related weak secretion signal peptide gene within the structure gene of Lb. Bulgaricus β-galactosidase, and its translation product may introduce the enzyme secretion out of cells in special hosts.
A Rabbit Model of Hormone-induced Early Avascular Necrosis of the Femoral Head
2008, 21(5): 398-403.
Objective To establish an experimental model of early stage avascular necrosis of the femoral head (ANFH) caused by corticosteroid in adult rabbits and to observe the pathological changes with various imaging techniques. Methods ANFH was induced by a combination of hypersensitivity vasculitis caused by injection of horse serum and subsequent administration of a high dose of corticosteroid. The pathological changes were detected with digital radiography (DR), computed tomography (CT), magnetic resonance imaging (MRI), ink artery infusion angiography, hematoxylin--eosin staining, and mmunohistochemistry. Results The imageological and athological changes corresponded to the clinical characteristics of early stage ANFH. DR showed bilaterally increased bone density, an unclear epiphyseal line, and blurred texture of cancellous bone. CT showed spot-like low-density imaging of cancellous bone, thinner cortical bone, osteoporosis, and an unclear epiphyseal line. MRI showed bone marrow edema and spot-like high signals in T2-weighted imaging in cancellous bone. Ink artery infusion angiography showed fewer obstructed blood vessels in the femoral head. HE staining of pathological sections showed fewer trabeculae and thin bone, an increased proportion of empty osteocyte lacunae, decreased hematopoiesis, thrombosis, and fat cell hypertrophy. Lmmunohistochemistry showed attenuated expression of vascular endothelial growth factor in osteoblasts and chondrocytes, and on the inner membrane of blood vessels. Conclusion Experimental rabbit model of early stage ANFH caused by corticosteroid can be successfully established and provide the foundation for developing effective methods to treat early stage ANFH.
Vulnerability to HIV Infection and Related Health Risk Behaviors of the Out of School Adolescents Migrated with Their Parents to Beijing
2008, 21(5): 404-410.
Objective To explore the vulnerability to HIV infection and related risk behaviors of the out-of-school adolescents who migrated with their parents from rural areas to cities. Methods From September to October 2005, 260 out-of-school adolescents aged 14-20 years were interviewed through a questionnaire. Results Out-of-school adolescents lacked HIV/AIDS knowledge and related life skills, and their psychosocial competency was relatively low. The interviewed adolescents were open in their sexuality, showing a low rate of condom use. Their attitudes towards people living with HIV/AIDS and HIV/AIDS prevention competency were positively correlated with family well-being, harmonious relations between their parents, a stable job, knowledge, life skill, and psychosocial competency for emotion control and empathy. Conclusion Out-of-school adolescents are highly vulnerable to HIV/AIDS infection and transmission. Practical and feasible health and life skill education and psychosocial competency are the keys to effective HIV/AIDS prevention among out-of-school adolescent migrants.
Parental Alcoholism, Adverse Childhood Experiences, and Later Risk of Personal Alcohol Abuse among Chinese Medical Students
2008, 21(5): 411-419.
Objective To determine the status of adverse childhood experiences (ACEs) and the association of multiple ACEs with both parental alcoholism and later personal alcohol abuse among Chinese medical students with a view of improving adolescent health and reducing alcohol abuse among them. Methods In this cross-sectional study, 2073 Chinese medical students completed a survey on ten categories of ACEs in Anhui province of China. The association of parental alcoholism with ACEs and personal lcohol abuse was assessed by logistic regression analyses. Results The adjusted odds ratio (OR) for each category of ACEs in the subjects whose parents (either fathers or mothers or oth) had alcohol abuse was 2 to 14 times higher than that inthose with parental alcoholism (P<0.05). Subjects with i-parental alcoholism had the highest likelihood of ACEs. Compared with the subjects without ACEs, the risk of personal alcohol abuse was increased by 2-4-folds in the subjects with ACEs, irrespective of parental alcoholism (P<0.05). The total number of ACEs (ACE score) had a graded relationship to 4 categories of personal alcohol abuse with or without parental alcoholism. The prevalence of personal alcohol abuse among the subjects with parental alcoholism was higher, which was ndependent of ACE scores. Conclusion The prevalence of ACEs is generally serious in China. Efforts should be made to prevent and treat children with ACEs and subsequently to reduce alcohol abuse and later problems.
Experimental Study of Cell Migration and Functional Differentiation of Transplanted Neural Stem Cells Co-labeled with Superparamagnetic Iron Oxide and Brdu in an Ischemic Rat Model
2008, 21(5): 420-424.
Objective To explore the migration of transplanted neural stem cells co-labeled with superparamagnetic iron oxide (SPIO) and bromodeoxyuridine (Brdu) using the 4.7T MR system and to study the cell differentiation with immuno-histochemical method in ischemic rats. Methods Rat neural stem cells (NSCs) co-labelled with SPIO mediated by poly-L-lysine and romodeoxyuridine (BrdU) were transplanted into the unaffected side of rat brain with middle cerebral artery occlusion (MCAO). At weeks 1, 2, 3, 4, 5, and 6 after MCAO, migration of the labelled cells was monitored by MRI. At week 6, the rats were killed and their brain tissue was cut according to the migration site of transplanted cells indicated by MRI and subjected to Prussian blue staining and immunohistochemical staining to observe the migration and differentiation of the transplanted NSCs. Results Three weeks after transplantation, the linear hypointensity area derived from the migration of labelled NSCs was observed by MRI in the corpus callosum adjacent to the injection site. Six weeks after the transplantation, the linear hypointensity area was moved toward the midline along the corpus callosum. MRI findings were confirmed by Prussian blue staining and immunohistochemical staining of the specimen at week 6 after the transplantation. Flourescence co-labelled immunohistochemical methods demonstrated that the transplanted NSCs could differentiate into astrocytes and neurons. Conclusion MRI can monitor the migration of SPIO-labelled NSCs after transplantation in a dynamical and non-invasive manner. NSCs transplanted into ischemic rats can differentiate into astrocytes and neurons during the process of migration.
Detection and Molecular Characterization of Enteroviruses in Korean Surface Water by Using Integrated Cell Culture Multiplex RT-PCR
2008, 21(5): 425-431.
Objective To identify waterborne enteric viruses in Korean surface water. Methods Integrated cell culture(ICC)-multiplex reverse transcription-polymerase chain reaction (RT-PCR) was simultaneously designed to detect coxsackieviruses (CV), polioviruses (PV), and reoviruses (RV). ICC-multiplex RT-PCR and phylogenetic analysis were conducted using 21 total culturable virus assay (TCVA)-positive sample-inoculated cell cultures. Results CV and RV were detected in 9 samples each, and 3 samples were positive for both CV and RV. PV was not etected in any sample. Molecular phylogenetic analysis of the VPl gene sequences revealed that CV types B2 and B4 redominated in Korean surface water, and the nucleotide sequences of CV type B2 were clustered with those of CVs isolated from China and Japan. The results suggested that the evolution of these viruses occurred in a region-specific manner. Conclusion CV and RV are detectable in Korean surface water, with a predominance of CV type B2, and the evolution of CV type B2 occur in a region-specific manner.
Spatiotemporal Property Analysis of Birth Defects in Wuxi, China
2008, 21(5): 432-437.
Objective To describe the temporal trends and spatial patterns of birth defects occurring in Wuxi, a developed region of China. Methods Wavelet analysis was used to decompose the temporal trends of birth defect prevalence based on the birth defect rates over the past 16 years. Birth defect cases with detailed personal and family information were geo-coded and the relative risk in each village was calculated. General G statistic was used to test the spatial property with different scales. Results Wavelet analysis showed an increasing temporal trend of birth defects in this region. Clustering analysis revealed that changes continued in the spatial patterns with different scales. Conclusion Wuxi is confronted with severe challenges to reduce birth defect prevalence. The risk factors are stable and show no change with spatial scale but an increasing temporal trend. Interventions should be focused on villages with a higher prevalence of birth defects.
Visible Light Induced Photodegradation and Phototoxicity of Phloxine B and Uranine
2008, 21(5): 438-441.
Objective To determine the visible light-induced photodegradation kinetics of two xanthene photosensitizers, phloxine B and uranine, in solution and on the surface of silica TLC plates, and to examine the phototoxicity of residues of degradation, which could provide valuable safety data on the two photosensitizers and other xanthene chemicals when applied in the environment. Methods UV-Vis absorption during hotodegradation was monitored with a Unico 2102 spectrophotometer. Organic content of samples was measured with a Shimadzu TOC 4100. Phototoxicity tests were carded out using Saccharomyces cerevisiae with the methods modified from Daniels. Results When phloxine B and uranine degraded in solution, their apparent rate constant k was 0.0019 and 0.0027 min-1, respectively. The total organic carbon (TOC) content decreased by approximately 50% during the 8 h irradiation period, which led to a gradual decrease in phototoxicity of the residues. The photodegradation of photosensitizers on the surface of silica TLC plates was much faster than that in the solution. The apparent rate constant k and the half life of phloxine B were 0.0073 min-1 and 95 min, respectively. Conclusion Visible light can rapidly induce photodegradation of phloxine B and ranine. The phototoxicity of residues is also decreased. The environmental risk of applications of phloxine B and uranine is minimal.
Effects of a Regional Chinese Diet and Its Vitamin Supplementation on Proliferation of Human Esophageal Cancer Cell Lines
2008, 21(5): 442-448.
Objective To study the effects of a local diet popular in Yanting region (YT diet) on the proliferation of two human cell lines (Eta-109 esophageal squamous cell carcinoma line and HL7702 normal liver epithelial cell line) in rats by a ero-physiological approach. Methods Male SD rats were divided into six groups and fed respectively with a conventional diet and the YT diet (one of the five experimental diets) supplemented with two vitamin mixtures (Mix.1: vitamins A, E, and folio acid; Mix.2: mix.l plus riboflavin and vitamin C) at two different doses. On the 30th day, sera were collected from the rats and added into a medium for cell culture, with 10% FBS used as a serum control. The effects were assessed by MTI" assay, DNA synthesis and flow cytometry assays. Results Compared with the control, the sera from rats fed with the YT diet significantly promoted the proliferation of Eca-109 cells, which was, however, reversed by the supplementation with two vitamin mixtures at high doses. Surprisingly, the same treatment produced contrary effects on HL7702 cells as compared with Eca-109 cells. Conclusion The sera from rats fed with the YT diet could promote the proliferation of human esophageal cancer cell line Eca-109, whereas the sera from those fed with the YT diet supplemented with vitamin mixtures might have inhibitory effects on the proliferation of Eca-109 cells.
Biomedical and Environmental Sciences INFOPRMATION FOR AUTHORS
2008, 21(5)