The relationship of Bdellovibrio and microbiological pollution was observed in laboratory.The results showed that the number of bd ellovibrio increased some time later than the introduction of polluted microbes and remained on high level after the pollution.These characteristics may have potential on indicating pollution.

2 weeks ) were screened by BAEP. Results Hearing-ability of 11 children(11/23,47.8%) was abnormal,one month later hearing-ability of 2 children was abnormal, and there months later hearing-ability of only 1 child was abnormal. Conclusion Hyperbilirubinemia may cause hearing-ability damage in neonates and BAEP is one of effective audiometric means.

Individual stature estim ation is one of the m ost im portant contents of forensic anthropology. C urrently, it has been used that the regression equations established by the data collected by direct m ea-surem ent or radiological techniques in a certain group of lim bs, irregular bones, and anatom ic landm arks. D ue to the im pact of population m obility, hum an physical im provem ent, racial and geographic differ-ences, estim ation of individual stature should be a regular study. T his paper review s the different m ethods of stature estim ation, briefly describes the advantages and disadvantages of each m ethod, and prospects a new research direction.

120 teeth with wedge-shaped defects at subgingival depth of 0 ~2 mm were selected and divided into 3 groups(n =40).Gingival retraction code and EXPASYL gingival retraction paste were used for gingival retraction in the 2 retraction groups,and none retraction was used in the control group.After restoration of the defects,all cases were followed up for 1 year and 2 years.The results were evaluated by modified USPHS criteria.No significant difference was detected for 1 year and 2 year successful rates between the extraction groups(P >0.05).The successful rate in extraction groups was higher than that in the control group(P ＜0.05).

Objective To investigate the effects of melatonin on oxidative stress and neuronal apoptosis in hippocampus of epileptic rats and the mechanism. Methods Seventy-two adult male Sprague-Dawley rats were equally divided into control group, model group, low dose group and high dose group. The model group was injected coriamyrtin 50μg/kg in the lateral ventricle, while the low dose group and high dose group were injected melatonin 20 mg/kg and 60 mg/kg, respectively, 30 minutes before injection of coriamyrtin. The contents of malo-ndialdehyde (MDA) and superoxide dismutase (SOD) were detected with ultraviolet spectrophotometer, the apoptosis was detected with TU-NEL, and the ultrastructural changes of neurons and mitochondria in hippocampal CA3 region were observed with electron microscopy, af-ter 60 minutes of epilepsy. Results The neurons and mitochondria in hippocampus were damaged, the number of apoptotic cells significant-ly increased (P<0.001), the content of SOD decreased (P<0.001), and the content of MDA increased (P<0.001) in the model group, com-pared with the control group. In the low dose group, the ultrastructural damage relieved, the number of apoptotic cells decreased (P<0.01), the content of SOD increased (P<0.05), and the content of MDA decreased (P<0.05);and for the high dose group, the ultrastructural damage relieved very much, the number of apoptotic cells decreased (P<0.001) and was not significantly different from the control group (P>0.05), SOD increased (P<0.001), and MDA decreased (P<0.001), compared with the model group. Conclusion Exogenous melatonin may signifi-cantly reduce neuronal apoptosis in rat hippocampal after epilepsy, and high dose is more effective, which may relate with resistance of oxi-dative stress, alleviate neuronal mitochondrial damage.

A large coverage on-line learning and examination systems on the internet so far has not gained wide usage and application even though some systems are available commercially because those internet based systems have certain demands of capitals , technology and skilled personals .Our system is half on -line and half off line for examinations .The on-line part is for giving out examination questions and collecting answers , whereas student writ-ing exams and instructors marking the exams are carried out by going off -line.Such a exam-writing application re-duces its dependence on the internet , which is easier for exam-writers in a remote area to use .This half on-line system can be used as a back -up application for the whole on -line examination system , but definitely has more ad-vantages for hospitals in remote areas where the internet is not reliable and popular , and well-trained technicians are lacking.

Objective To evaluate the mutagenicity of mercury, cadmium, arsenic, chromium(Ⅵ)and lead in water on Vicia faba root tip cells. Methods The micronucleus assay of Vicia faba root tip cells were conducted to determine micronucleus rate of Vicia faba root tip cells induced by mercury (0.000 5-1.0 mg/L), cadmium (0.005-1.0 mg/L), arsenic(0.05-2.0 mg/L), chromium (Ⅵ) (0.05-2.0 mg/L) and lead (0.05-3.0 mg/L ) ,and pollution indexes were calculated. Results When the concentration of mercury was ≥ 0.5 mg/L, cadmium ≥ 0.1 mg/L, arsenic ≥ 0.5 mg/L and chromium(Ⅵ)≥ 2.0 mg/L in the water, the micronucleus rate were significantly higher compared with the negative control group, respectively(P

Objective To determine the urine lead level in school_age children under conditions of environmental lead exposure and evaluate the effects of the presence of body lead on IQ, academic achievement and behavior in school of these children. Methods The concentrations of urine lead and IQs for 118 children aged 7～12 were measured. The academic achievement, behavior in school and the correlated factors were derived from the questionnaires given to their teachers and parents. Results The urine lead level of 118 children was (7.04?3.53)?g/L. In children who lived in city central area the urine lead level was (7.71?3.52)?g/L. It was significantly higher than that of children who lived in a suburban area [(6.37?3.45)?g/L]; No significant differences were observed in IQ between children in city and suburbs. The results by single factor analysis showed that the urine lead level [(10.31?2.16)?g/L] in the lower IQ group (IQ

ve To assess the cytogenetic toxicological safety of fish raised in water containing effluent. Methods The mutagenecity of organic extracts of uncooked meat specimens of fish raised in fishpond water mixed with sewage water taken from South and North Sewer Drainage Canals of Tianjin was detected by mice bone marrow micronucleus test. Results The organic extracts of uncooked fish meat specimens showed positive result for all of the 3 observed groups of fish raised in water of fish ponds with sewage, and negative result for fish raised in clean fishpond water in micronucleus test. Conclusion The results indicated that some kinds of organic mutagenic compounds ex-isted in the uncooked meat of fish raised in fishpond water containing effluent, which might have some potentially hazardous effects on human health through the food chains.

Objective To study the mutagenicity of fish-raising water containing effluent. Methods The niuta-genieities of water samples from waste water canal, the fish-raising water(fish-pond water) treated by presedimenta-tion in oxidation tank were detected using micronucleus test of vicia faba root tip cells. The micronucleus test of peripheral red blood cells was carried out among fish raised in water containing effluent. The water samples and fish collected from reservoir as controls. Results The micronucleus test of vicia faba root tip cells showed that the micronucleus rates in treated fish-pond water and waste water were significantly higher than those of negative control group (distilled water) (P 0.05) . The frequencies of micronucleus in peripheral red blood cells of fish raised in treated fish-pond water were significantly higher than those of fish raised in reservior water (P