Purpose : To study the relationship of the telomere length and telomerase activity to immortalization or malignant t ransformation of the immortalized esophageal epithelial cell line (SHEE) and malignantly t ransformed cell line (SHEEC) induced by E6 and E7 genes of HPV 18 type. Methods : Using SHEE and SHEEC cell lines , the telomere length (mean length of telomere rest riction f ragment s , TRF) was examined by Southern blotting , the telomerase activity by the PCR2based telomeric repeat amplification protocol ( TRAP) and the expression of human telomerase reverse t ranscriptase ( hTERT) and human telomerase RNA ( hTR) by reverse t ranscription polymerase chain reaction(RT - PCR) . Results : The telomere length in the SHEE and SHEEC was significantly shorter than that in the normal esophageal epithelial tissue , but maintained a stable length. The telomerase activity and it s subunit hTERT and hTR were observed in the SHEE and SHEEC. Conclusion : A possible cause of stable division of SHEE and SHEEC is telomerase reactivitied , which maintains the telomere at a shortened and stable length.

Purpose : To detect the neurobehavioral teratogenic effect of methylmercury exposure at early embryonic stage on off spring. Methods : Methylmercury chloride was force2fed to the Wistar rat s during the 6th～9th day after conception at doses of 0. 00 mg/ (kg·bw·d) , 0. 01 mg/ (kg·bw·d) , 0. 05 mg/ (kg·bw·d) and 2. 00mg/ (kg·bw·d) . The toxicity in the embryos , developmental landmarks of 201 off spring and operant behavior test of 32 off spring were measured. The brain morphology and the levels of monamine neurot ransmitters (NA ,DA , 52HT) were tested in 24 off spring at 10 weeks old. Double blind was used in whole experiment . Results :In 3 exposure groups , the body weight and tail development of embryos were slower ( P < 0. 01) , the early developmental landmarks and neurobehavioral development of off spring were delayed ( P < 0. 05) , and their performances in operant behavior were worse than those of the cont rol group ( P < 0. 05) . No histomorphological alteration in the off spring brains was observed in all groups. The levels of monamine neurot ransmitters in brains of 3 exposure groups were increased ( P < 0. 05) . Some result s showed a dose2effect relationship. Conclusion : Early pregnant exposure to methylmercury at a low dose showed some embryotoxicity and adverse effect s on the developing nervous system of the rat off spring and also resulted in neurobehavioral changes.

Purpose : To investigate the antitumor effect and mechanisms of Zhenxiang capsule (ZXC) on human esophageal carcinoma. Methods : Apoptosis induced by ZXC in human esophageal carcinoma cell line EC109 was investigated by optical microscopy , transmission elect ron microscopy and flow cytomet ry. Antitumor effect of ZXC was observed on human esophageal carcinoma xenograft in nude mice. Results : After exposure to ZXC ,EC109 cells manifested typical apoptotic features. The tumor2inhibiting rates in the groups of ZXC 4 800 mg/(kg·bw) , 2 400 mg/ (kg·bw) and 1 200 mg/ (kg·bw) ranged f rom 70. 80 % to 75. 00 %( P < 0. 01) , 58. 33 % to 64. 71 %( P < 0. 01) and 37. 04 % to 45. 10 %( P < 0. 01) , respectively. The tumor2inhibiting rates of the pingyangmycin (15 mg/ (kg·bw) ) group ranged f rom 51. 33 % to 60. 78 %( P < 0. 01) . Conclusion : ZXC induces apoptosis of esophageal carcinoma cells in vit ro , which is possibly the primary mechamism of ZXC inhibition of esophageal carcinoma. ZXC has significant antitumor effect on human esophageal carcinoma t ransplanted into nude mice at tolerant doses. The antitumor effect increases with dosage.

Purpose : To study the effect s of lycopene on the carcinogenicity of N2methyl2N2amylnit rosamine (MANA) in Wistar rat s. Methods : The rat s were randomly divided into three groups : simple MANA (M) ,MANA plus tomato jam (M + L P) and cont rol (C) groups. The experiment lasted 26 weeks. Histological examination was done and the levels of ROS unit , SOD , GSH2Px and MDA in the blood were determined. Results : There were precancerous lesions of esophagus or forestomach in the M and M + L P groups. The incidence of precancerous lesions in the M + L P group was decreased , and the levels of ROS unit , SOD , GSH2Px in the blood were higher , but the content of MDA was decreased. Conclusion : Lycopene may have an inhibitory effect on the carcinogenicity of MANA. The effect may be due to the inhibition of lipid peroxidation.

Purpose and Methods : Single cell gel elect rophoresis ( SCGE) , sister chromatid exchanges ( SCE) ,chromosome aberrations are three methods to determine DNA damage and repair. The purpose of this study was to compare the sensitivity and accuracy of the three methods. Results : SCGE was the most sensitive one for detecting DNA damage induced by H2O2 . The rates of DNA damage at 100μmol/ L and 200μmol/ L of H2O2 were 45. 6 % and 59. 5 % measured by SCGE , and 3. 4 % and 5. 3 % by SCE , respectively. DNA damage induced by H2O2 was not detectable with chromosome aberration method. Conclusion : SCGE , SCE and chromosome aberration were considered to be used in three different levels , whereas SCGE was a quick , simple and more sensitive technique for detecting DNA damage and repair.

Purpose : To study the micronuclear changes in t ransplantable T cell leukemia model (L7212 cells) after ult raviolet irradiation. Method : Cytokinesis2block (CB) micronucleus method was used. Results : The micronucleated cell and micronucleus frequencies in the CB2blocked model ( + CB group) were higher than those in the 2CB cont rol group when the dosage was over 45 ×10 - 7 J / (s·mm2) . A dose2effect curve showed the relation ship of Y= a + blgX( P < 0. 01) . Conclusion : Cytokinesis2block micronucleus method is more sensitive than the conventional culture for the measurement of micronuclei induced by ult raviolet irradiation.

Purpose : To study the antitumour effect s of the water ext ract s of Cnidium monnieri L . cuss in vi2 vo. Methods : Mice carrying S180 tumor were given different doses of the water ext ract s , then the tumor weight , the survival days of the animals and the SA in serum were observed. Results : The tumor weight were lower thancont rol group when the doses of water ext ract s were 0. 04 mg/ (g·bw·d) , 0. 21 mg/ (g·bw·d) and 0. 42 mg/ (g·bw·d) , The inhibitory rates were 34. 2 % , 63. 6 % and 33. 2 % , respectively. The water ext ract s also couldextend the survival days of mice carrying S180 tumor ( P < 0. 01) and the extending rates were 53. 0 % , 58. 3 %and 47. 0 % in turn. Conclusion : The water ext ract s of cnidium monnieri L . Cuss had a good effect of antitumor. It is worth studying on it deeply.

Purpose : To investigate the effect s of organic chemical pollutant s in water f rom Bengbu (N) section of Huai river on mouse gentoxicity and lipid peroxidation. Methods : Organic chemical concent rates of water were taken f rom the lower and the upper N sections of Huai River , the water works , and the dist ribution network ,respectively , and the mouse micronucleus test , sperm deformity test were used to detect their gentoxicity. Lipid peroxides (L PO) , superoxide dismutase (SOD) and glutathione peroxidase ( GSH2Px) were also determined. Results : The positive mutagenicity to a certain degree was induced by the organic chemical concent rates of the water samples ( P < 0. 05～0. 01) , high levels of L PO and lower activities of SOD and GSH2Px were found. Conclusion : Organic chemical pollutant s of the water in the N section of Huai River have potential genotoxicity and influence on mouse lipid peroxidation.

Purpose and Methods : The mutagenicity and teratogenicity of stalk and leaf of Tri pterygium wilf ordii Hook . f ( TWHf ) were examined by chromosome aberration , micronucleus and teratogenic test s. Results : TWHf did not induce chromosome aberration and increase the f requency of micronuclei in mice , and had not significant teratogenicity. However , in high dose group it showed embryotoxicity , and the rates of fetal death obviously increased. Conclusion : Great attention should be paid when this drug is used for pregnant woman.

Purpose : To investigate the mutagenic effect s of seven pesticides on human and plant chromosomes ,and compare their SCE2inducing effect s in human lymphocytes with those in plant root tip cells. Methods : Sister-chromatid exchange ( SCE) f reqency was determined in human lymphocytes and plant root tip cells after treatment s with pesticides. Results : Seven pesticides all induced a does2dependent increase of SCE in plant root tip cells and in human lymphocytes. Conclusion : The pesticides have st rong mutagenic effect s to human and plant chromosomes and have the same efficency in human lymphocytes and plant root tip cells.