Objective To investigate the effects of maternal long-term exposure to low-dose trichlorfon on the serum paraoxonase (PON) activity of pregnant mice and development of embryos. Methods Female ICR mice (n=120) were randomly divided into control group and trichlorfon groups of different doses,and were managed by intragastric injection with trichlorfon of 0,2,10 and 50mg/kg,respectively. All the mice were managed once a day for a consecutive of 27 days,and were subjected to mating. The pregnant mice were continued to be managed with trichlorfon for 3 days,and were sacrificed on day 3 of gestation. The serum PON and acetylcholinesterase (AchE) activities were detected,and the development of embryos was evaluated. Results The serum PON activity of 2,10 and 50mg/kg trichlorfon group were (14.15?1.22),(12.78?1.80) and (10.45?1.95)IU/mL,respectively,and that of 50mg/kg trichlorfon group was significantly lower than that of control group [(13.37?2.31)IU/mL] (P0.05),while the the percentage of abnormal embryos of 50mg/kg trichlorfon group had an increased tendency. Conclusion Long-term exposure to low-dose trichlorfon can inhibit serum PON and AchE activity in pregnant mice without obvious effect on the development of embryos.

This study is to clone the gene of staphylococcal enterotoxins O, obtain recombinant protein (rSEO) and investigate its activity on mice lymphocyte. Staphylococcus aureus O gene is cloned into GST gene fusion vector pGEX-4T-1. The resultant plasmid pGEX-4T-SEO was used to transform E. coLi BL21, where the GST-SEO fusion protein was expressed efficiently. Then SEO was purified by Glutathione Sepharose 4B affinity column and digested with thrombin. The bioactivity of SEO was analyzed by MTT assay on mice lymphocyte and tumor cells. The nucleotide sequence was confirmed to code for the protein correctly, and soluble SEO was expressed efficiently in E. coli BL21 with pGEX-4T-SEO. The protein purified by affinity chromatography resulted to be one single band by SDS-PAGE detection. The MTT assay of the purified rSEO demonstrated that its abilities of stimulating T cells and inhibiting the proliferation of K562, K562-ADM and B16 cells were equivalent to that of SEC in vitro. The expression plasmid pGEX-4T-SEO was constructed and the recombinant superantigen was expressed successfully, which may provide a foundation for the further research of the anticancer activity of SEO.
Animals ; Cell Proliferation ; Cloning, Molecular ; Enterotoxins ; genetics ; immunology ; metabolism ; Escherichia coli ; genetics ; metabolism ; Female ; Genetic Vectors ; Humans ; K562 Cells ; Lymphocytes ; cytology ; Male ; Melanoma, Experimental ; pathology ; Mice ; Mice, Inbred ICR ; Plasmids ; Recombinant Fusion Proteins ; genetics ; immunology ; metabolism ; Spleen ; cytology ; Staphylococcus aureus ; genetics ; Superantigens ; genetics ; immunology ; metabolism

OBJECTIVETo prepare and identify monoclonal antibodies against staphylococcal enterotoxin I (SEI).

METHODSSpleen cells obtained from mice immunized with the SEI protein were fused with the myeloma cells (SP2/0). Hybridomas were screened by enzyme-linked immunosorbent assay (ELISA) and the stable monoclonal hybridomas were isolated by limiting dilution at least three times. The characters of purified monoclonal antibodies were identified by indirect ELISA and Western blotting.

RESULTThe monoclonal antibodies secreted by two hybridomas 8F7 and D8 belonged to IgG(2b) and IgG(1) subtypes. Both had high titer and specificity with no cross reaction to SEG, SEE and SEC.

CONCLUSIONThe monoclonal antibodies against SEI has been successfully prepared and identified in this study.

Animals ; Antibodies, Monoclonal ; biosynthesis ; immunology ; Enterotoxins ; immunology ; Hybridomas ; secretion ; Immunoglobulin G ; biosynthesis ; immunology ; Mice ; Mice, Inbred BALB C ; Spleen ; cytology ; Staphylococcus aureus ; immunology

The filtrate of Staphylococcus aureus culture has been used in an ampule form named as staphylococcal enterotoxin C injection for cancer therapy in clinic for ten years in China and proved to be effective. The active constituent of three kinds of injections is claimed to be staphylococcal enterotoxin C2 (SEC2), and the content of SEC2 is used as quality control. However, the correct content of SEC2 was not known and the relative amount of SEC2 was very low because of the complicated components of the filtrate. In this research, we established a proper ELISA system for the detection of SEC2 in staphylococcal enterotoxin C injection, which will improve the quality control of the injection. We produced and identified polyclonal and monoclonal antibodies of SEC2 and established BA-ELISA method based on the method of sandwich ELISA. It was found that the BA-ELISA method had good specificity, sensitivity and reproducibility, and being able to detect SEC2 at concentration from 2 to 20 ng x mL(-1), with an average CV value of 5.08%. The SEC2 content in staphylococcal enterotoxin C injection was calculated. There is some difference between the actual and labeled contents in the injections.
Animals ; Antibodies, Bacterial ; biosynthesis ; immunology ; Antibodies, Monoclonal ; biosynthesis ; immunology ; Antineoplastic Agents ; administration & dosage ; analysis ; immunology ; Enterotoxins ; administration & dosage ; analysis ; immunology ; Enzyme-Linked Immunosorbent Assay ; methods ; Hybridomas ; secretion ; Injections ; Mice ; Mice, Inbred BALB C ; Quality Control ; Rabbits ; Staphylococcus aureus ; chemistry

Objective To explore the relationship between dynamic changes in ultra-micro-structural of pulmonary arteries and endogenous hydrogen sulfide in rats with left-right shunt.Methods Rats in shunt group were subjected to an abdominal aorta-inferior vena cava shunt to create an animal model of pulmonary artery structural remodeling. After 1 day, 3 days, 1 week, 4 weeks and 8 weeks of experiment, the ultra-micro-morphologic changes of pulmonary arteries of rats were observed under electronic microscope and H_2S concentration in serum was evaluated by modified sulfide electrode method.Results The changes of ultra-micro-structure of pulmonary arteries were progressively exacerbated, endothelial cells became swollen and large in size on 3 days, smooth muscular cells increased in size as well as the change of endothelial cells in 1 week, and they changed from contractile phenotype to synthetic phenotype in 4 weeks.Conclusions Shunt exhibited changes of ultra-micro-structure of pulmonary arteries are accompanied by the changes of endogenous H_2S. It is suggested that endogenous H_2S might play a protective role in changes of ultra-micro-structure of pulmonary artery.

Objective To investigate the fulfillment of improved water measures for endemic fluomsis and to find out the trend of prevalence in Qinghai Province in order to provide scientific basis and technical support for the government to formulate control strategies for endemic fluorosis.Methods Usage and management of reforming water facilities in Huzhu County were generally surveyed.Yanya Village,Caijiabu Town,Huzhu County was chosen as the surveillance spot.The household drinking water was surveyed.The dental fluorosis and urine fluoride content of children aged 8-12 years and adult above 16 years were examined.Skeletal fluorosis of adult was checked.The fluomsis content in drinking water and urine was determined with F-ion selective electrode method.The dental fluowsis was examined with Dean index.Skeletal fluorosis was diagnosed according to eountry standard(GB 16396-1996.WS 192-1999).Results The rate of water-improving was 60%(36/60)in Huzhu County.The mean of fluoride content in drinking water Was 1.25 mg/L The prevalence rate of dental fluorosis of children aged 8-12 years was 90.20%(46/51);that of adult was 88.89%(48/54).The dental fluorosis index of children was 1.77,that of adult was 2.95.The prevalence rate of skeletal fluorosis was 98.15% indicated by clinical data,18.87% by X-ray.The ufine fluorosis content of children was 2.27 mg/L,that of adult was 2.00 mg/L.Conclusion The disease condition of endemic fluorosis in Qinshai is serious,defluofidation is slow in effect.

OBJECTIVETo study the value of screening hereditary nonpolyposis colorectal cancer (HNPCC) kindreds by detecting the expressions of hMLH1/hMSH2 with tissue microarray.

METHODSA tissue microarray with 22 colorectal cancers from HNPCC families and 15 sporadic colorectal cancers was established, and the expressions of hMLH1/hMSH2 were detected by immunohistochemistry (IHC).

RESULTSThe expressions of hMLH1 or hMSH2 were negative in 15 of 22 HNPCC and 1 of 15 sporadic colorectal cancers in routine IHC. The expressions of hMLH1 or hMSH2 were negative in 17 of 22 HNPCC and 2 of 15 sporadic colorectal cancers in tissue microarray. The examination of hMSH2 expression yielded same results between routine IHC and tissue microarray. There were no difference on the hMLH1 expressions between routine IHC and tissue microarray.

CONCLUSIONTissue microarray is a high-throughput way to detect the expressions of hMLH1/hMSH2 and is applicable to screen HNPCC kindreds.

Adaptor Proteins, Signal Transducing ; metabolism ; Adult ; Aged ; Colorectal Neoplasms, Hereditary Nonpolyposis ; diagnosis ; genetics ; metabolism ; DNA Methylation ; Female ; Gene Frequency ; Genetic Testing ; Humans ; Immunohistochemistry ; Male ; Middle Aged ; MutL Protein Homolog 1 ; MutS Homolog 2 Protein ; metabolism ; Nuclear Proteins ; metabolism ; Pedigree ; Protein Array Analysis ; methods

OBJECTIVETo investigate the limited digestion of recombinant staphylococcal enterotoxin C2 (SEC2-His)in different conditions.

METHODSThe purified recombinant SEC2-His was treated with different reagents and the cleavage of rSEC2 molecule was observed by SDS-PAGE.

RESULTThe cleavage occurred in positions Cys93-Cys110 of the disulfide loop. Complete auto-cleavage of recombinant SEC2 was observed in solution at 37degrees within 24 hrs, and that was accelerated under alkaline conditions. The auto-cleavage of the recombinant protein was inhibited in the presence of beta-ME (2%), PMSF (5-10 mmol/L), imidazole (1 mol/L) or crude E.coli lysate. Non-specific degradation of recombinant SEC2 was promoted with the increasing of the concentration of H(2)O(2).

CONCLUSIONThe recombinant SEC2-His is broken down in special site of protein, which may be associated with the protein structure.

Amino Acid Sequence ; Enterotoxins ; chemistry ; genetics ; Molecular Sequence Data ; Protein Conformation ; Protein Stability ; Recombinant Fusion Proteins ; chemistry ; genetics

Vehicle emissions are a major source of air pollution in urban areas. The impact on urban air quality could be reduced if the trends of vehicle emissions are well understood. In the present study, the real-world emissions of vehicles were measured using a remote sensing system at five sites in Hangzhou, China from February 2004 to August 2005. More than 48000 valid gasoline powered vehicle emissions of carbon monoxide (CO), hydrocarbons (HC) and nitrogen oxide (NO) were measured. The results show that petrol vehicle fleet in Hangzhou has considerably high CO emissions, with the average emission concentration of 2.71%+/-0.02%, while HC and NO emissions are relatively lower, with the average emission concentration of (153.72+/-1.16)x10(-6) and (233.53+/-1.80)x10(-6), respectively. Quintile analysis of both average emission concentration and total amount emissions by model year suggests that in-use emission differences between well maintained and badly maintained vehicles are larger than the age-dependent deterioration of emissions. In addition, relatively new high polluting vehicles are the greatest contributors to fleet emissions with, for example, 46.55% of carbon monoxide fleet emissions being produced by the top quintile high emitting vehicles from model years 2000-2004. Therefore, fleet emissions could be significantly reduced if new highly polluting vehicles were subject to effective emissions testing followed by appropriate remedial action.
Automobiles ; statistics & numerical data ; Carbon Monoxide ; analysis ; China ; Cities ; statistics & numerical data ; Environmental Monitoring ; methods ; Hydrocarbons ; analysis ; Nitric Oxide ; analysis ; Vehicle Emissions ; analysis

OBJECTIVEThe purpose of this study was to qualitatively and quantitatively analyze the initial force system of "rocking-chair archwire" on every tooth.

METHODSThree-dimensional finite element model of "rocking-chair archwire" was set up, and nonlinear method was used to analyze the force system.

RESULTSThe archwire exerted intruding force, labial force, lingual-root torque and mesial-labial moment on incisors; Extruding force, lingual-root torque and mesial-labial moment were applied on canines and premolars; The archwire also created intruding force, buccal force, buccal-root torque and mesial-labial moment on molars.

CONCLUSIONS"rocking-chair archwire" produced a complicated force system. While intruding incisors, molars and extruding premolars. It has a tendency to induce tooth rotation and tipping.

Dental Stress Analysis ; Finite Element Analysis ; Humans ; Malocclusion ; therapy ; Orthodontic Appliance Design ; Orthodontic Wires ; Orthodontics, Corrective ; methods