Albino rats fed on crops from endemic and non-endemic districts of Ke-shan desease, were used in this experiment, which was studied by 85Zn tracer metabolic method after 8 weeks feeding. Uptake of 85Zn (ZnCl2) by blood, heart, liver, kidneys and brown adipose tissue were determined at 24 and 72 hours after injection of this tracer respectively, and its distribution was thoroughly examined. The results revealed that the uptake of 8aZn was higher in the groups fed on crops from endemic districts, particularly significant in liver, kidneys and brown adipose tissue. This may reflect the lacking or deficiency of zinc in the bodies.The regular differences of 85Zn between two groups were certainly related to the crops produced from endemic or aon-endemic districts. In other words, there should be some differences between crops from endemic and non-endemic areas. Thus more attention should be paid to the factors in endemic crops, which induced lacking or deficiency of zinc in the experimental animal and to its relationship with etiology of Keshan disease.

The effects of manganese on selenium content and glutathione peroxidaseactivity in blood and myocardium, and on selenium excretion in growing ratswere studied to ferret out the interaction of the two essential trace elements.Manganese dichloride (40mg/kg of MnCl2.4H2O) was administered daily to a group of 17 rats for 35 days intraperitoneally. An obvious increase in manganese content in serum and myocardium was induced. However, selenium levels in the two tissues of manganese-treated rats were significantly lower than the controls. From the 14th day on, glutathione peroxidase activities in whole blood of manganese-treated rats were below the controls, and on the 35th day, the activities of the selenium-containing enzyme in blood and myocardium were reduced by 29.33% (P

AIM: To explore the kinetics and thermodynamics parameters in the extraction of flavonoids from Fagopyrum tartarjcum . METHODS: Rutin was adopted as marker substance to create a regression equation between Rutin concentration and absorbance by meaus of UV. RESULTS: According to Fick diffusion principle Ⅱ, extraction process was analysed to gain parameters, such as K, Ea, Y, t 1/2 , K ?. CONCLUSION: The method would be useful for the process design and the choice of operation condition to extract flavonoids from Fagopyrum tartarjcum.

Observations were conducted on 11 kinds of tissues and organs(brown adipose tissue, thymus gland, blood, heart, lungs, muscle, bone, kidneys, spleen, liver, and intestine) in experimental animals, which were fed on crops from endemic areas of Keshan disease and non-endemic areas for 8-13 weeks. The absorption and distribution of 75Se (Na2 SeO3) in above tissue and organs were studied. Results revealed that the absorption of Na2-SeO3 in experimental group fed on crops from endemic area was higher than control group fed on crops from non-endemic area. The gradient of distribution of 75Se in various organs was regular: The highest absorption was in kidneys, the lesser was in liver, spleen and thyrnus, the least was in muscle, heart and bones.In one week observation, the contents of 75Se changed as time passed, but the fluctuating changes of the two groups were different.The regular differences of 75Se absorption as above, revealed a distinction between endemic and non-endemic crops. Under the influences of the crops on experimental animals, there appeared more or less a condition of selenium deficiency, which proved that the soil-water-food chain had apparently influenced the selenium metabolism of the organisms.

OBJECTIVE: To explore an improved method for determination of cyclohexane and methylcyclohexane in workplace air by solvent desorption-gas chromatography. METHODS: Cyclohexane and methylcyclohexane in workplace air were collected by activated carbon tubes,desorbed with carbon disulfide,separated by DB-1 capillary chromatography column,detected by flame ionization detector and quantified using the standard calibration curves. RESULTS: The linear range of the concentration of cyclohexane and methylcyclohexane were 1. 0-1 402. 2 and 0. 8-1 999. 4 mg / L respectively.Both the correlation coefficients were 0. 999 9. Both the detection limits were 0. 3 mg / L. The limits of quantification were1. 0 and 0. 8 mg / L respectively. Both the minimum detectable concentrations were 0. 2 mg / m3. The minimum quantitative mass concentrations of cyclohexane and methylcyclohexane were 0. 7 and 0. 6 mg / m3respectively( sample volume was 1. 5L). The average desorption efficiencies were 98. 5%-99. 3% and 97. 6%-99. 0% respectively. The relative standard deviations( RSD) of within-run precision were 0. 36%-0. 59% and 0. 34%-0. 50% respectively. The RSD of between-run precision were 0. 89%-2. 04% and 0. 87%-2. 22% respectively. The samples could be stored for up to 7 days at room temperature. CONCLUSION: This method has features of simple operation,high sensitivity and good precision,which is suitable for simultaneous determination of cyclohexane and methylcyclohexane in workplace air.

OBJECTIVE: To explore the effects of cadmium chloride( CdCl_2) on DNA single strand breaks and the production of 8-hydroxy-2'-deoxyguanosine( 8-OHdG) in human embryonic kidney epithelial cells( HEK cells). METHODS: HEK cells in logarithm growth phase were divided into 5 groups and incubated with the different concentrations of CdCl_2( 0. 0,2. 5,5. 0,10. 0 and 20. 0 μmol/L) for 24,48 and 72 hours in vitro. After harvesting the cells,DNA single strand breaks was tested by single cell gel electrophoresis,and the level of 8-OHdG was measured using the enzyme linked immunosorbent assay. RESULTS: The Olive tail moment was statistically significant in the main effect of CdCl_2 exposed HEK cells( P < 0. 01). Among them,when HEK cells were exposed to 5. 0 μmol / L of CdCl_2,the Olive tail moment began to have a statistical significant increasing trend compared with the 0. 0 μmol / L group( P < 0. 05); when CdCl_2 concentration was 2. 5-10. 0 μmol / L,the Olive tail moment lengthened with the increasing dose of cadmium exposure,showing a doseeffect relationship( P < 0. 05). The tail DNA% was statistically significant in the interaction between exposure treatment and exposure time in HEK cells( P < 0. 01). Among them,when CdCl_2 concentration was at 2. 5-10. 0 μmol / L at 24 hours time point and 5. 0-20. 0 μmol / L at 48 hours time point,the tail DNA% raised with the increasing dose of cadmium exposure,showing a dose-effect relationship( P < 0. 05). The tail DNA% at 3 time points of 24,48 and 72 hours after exposure to 20. 0 μmol / L of CdCl_2 in HEK cells increased with the increasing time of cadmium exposure,showing a timeeffect relationship( P < 0. 05). The level of 8-OHdG had statistical significance in the main effect of CdCl_2 exposure treatment in HEK cells( P < 0. 05). Among them,the level of 8-OHdG was first significantly increased only after exposure to 10. 0 μmol / L CdCl_2 compared with the 0. 0 μmol / L group( P < 0. 05). After treatment with Ca Cl2,there was no doseeffect relationship and time-effect relationship found between the cadmium chloride exposure and tail length as well as the tail / head length ratio and 8-OHdG level. CONCLUSION: To a certain extent,CdCl_2 exposure may cause both DNA single strand breaks and 8-OHdG production in HEK cells. Compared with 8-OHdG,the DNA single strand breaks show more significant change with a lower dose of cadmium treatment,which may be related to its higher sensitivity to cadmium toxicity than 8-OHdG.

Objective:This study aimed to construct a lentiviral expression vector for microRNA-194 and investigate its effect on the metastasis of human osteosarcoma cell line U2-OS. Methods:Pri-and mature miR-194 amplified by PCR were inserted into the plenty-GFP vector and identified by restriction endonuclease digestion and nucleotide sequencing. The osteosarcoma cell line U2-OS was transfected with the lentivirus. Then, the stable transfected cells were used in Transwell and wound healing assay. Results:Restric-tion analysis and sequencing showed that the recombinant lentiviral expression vector was constructed correctly. The titers of obtained overexpression and suppression expression recombinant lentivirus were 1.5*108 and 4*108 TU/ml. Cell metastasis ability was signifi-cantly different in different experimental groups (P<0.01). Conclusion:The lentiviral expression vector for microRNA-194 was suc-cessfully constructed. MicroRNA-194 could influence the metastasis of the osteosarcoma cell line U2-OS;thus, it could be further ex-plored as a potential target in osteosarcoma therapy.

OBJECTIVETo explore the feasibility of preparation of a mouse model of orthotopic colon cancer by injecting tumor cell suspension into mesenteric triangle of the cecum.

METHODSTwenty SPF 8-week old BALB/c mice (male:female = 1:1) were used in this study. The mouse caecum was exposed by laparostomy, and suspension of mouse colon adenocarcinoma CT26. WT cells was injected into the mesenteric triangle of cecum for preparation of a mouse model of orthotopic colon cancer.

RESULTSMouse orthotopic colon cancer was developed by injection of tumor cell suspension into mesenteric triangle of the cecum showing a successful rate of 100%, without intestinal obstruction, and the liver, spleen, diaphragm and mesenteric lymph nodes metastasis rates were high in all the 20 experimental mice.

CONCLUSIONSThe establishment of mouse models of orthotopic colon cancer by injection of tumor cell suspension into the mesenteric triangle is a simple, rapid, and easy to master procedure, causing less damage to the colon wall, safe and with less trauma to the mice. This method may provide an ideal mouse model of orthotopic colon cancer for the study of pathogenesis as well as liver metastasis mechanisms of colon cancer.

Adenocarcinoma ; pathology ; secondary ; Animals ; Cecal Neoplasms ; pathology ; Cecum ; Colonic Neoplasms ; pathology ; Disease Models, Animal ; Feasibility Studies ; Female ; Liver Neoplasms ; secondary ; Lymphatic Metastasis ; Male ; Mice ; Mice, Inbred BALB C ; Neoplasm Transplantation ; methods