In the present study, it has been found that garlic extract has the ability of blocking the formation of DMN, DEN and DBN in vitro under the conditions simulating those of gastric juice. There are very good dose-response relationships between the dosage of garlic extract and the blocking effect on the formation of DEN and DBN.The concentration of nitrite can be lowered with garlic extract. The dosage of garlic extract and the remains of nitrite show highly significant negative correlations. This may be partial mechanism of blocking effect of garlic extract on the formation of nitrosamines.

It is well known that some moulds can mediate the formation o NO-com-pounds (NOC), but there have been few means to block its action. In this paper, we introduce garlic extract that can block moulds-mediated nitrosa-tion.Fusarium moniliforme and Aspergillus versicolor were inoculated in Cza-pek's liquid medium with nitrite and diethylamine ordibutylamine added (test group). The concentrations of NDEA and NDBA were higher in the test group than those in the control group (moulds not inoculated), (P

potato. The rates for removing nitrite also showed the same order.A new compound formed from the reaction of allyl mercaptan with sodium nitrite had characteristic absorption peaks of -NO group at 1508 CM-1 and 650 CM-1 of infrared spectrum. With UV-ray irradiating this new compound, the NO7 radical was regenerated. UV/Vis spectrum scanning also showed the specific absorption of R-SNO compounds. Based on the facts mentioned above and the rules by which -SH compounds react with nitrite to form R-SNO compounds, the molecular structure of this new compound can be described as CH2= CH-CH2-SNO, named "Allylthionitrite".In conclusion, -SH compounds in garlic extract could be competitively reacted with nitrite forming thionitrite compounds and then blocked the formation of nitrosamines. We believed this might be the partial mechanism of the blocking effect of garlic on the formation of nitrosamines.

Objective:To evaluate the influence of cervical collar height on the compressive strength of CAD/CAMzirconia-ceramic restoration.Methods:Zirconia cores were manufactured and divided into 5 groups (n =1 0)based on the cervical collar height(mm):0.0(A),1 .0(B),1 .5(C),2.0(D)and 2.5(E).After veneered with porcelain,all the samples were cemented on the metal tooth analog and then mounted in an universal test machine.The force was applied at a crosshead speed of 1 mm/min until catastrophic fail-ure occurred.Fracture loads and failure modes were recorded.Results:Mean of the fracture strength values(kN)in group A,B,C, D and E were 0.95 ±0.39,1 .29 ±0.50,1 .54 ±0.28,2.04 ±0.1 9 and 2.27 ±0.53 respectively(among groups,P <0.05).Two types of fracture modes were observed:chipping of the veneering porcelain and fracture of the veneering porcelain together with the framework.Conclusion:Zirconia coping design with 1 .5 mm cervical collar height may increase the compressive strength of CAD/CAMzirconia-ceramic restoration.

Objective To assess the clinical application of STIR sequences in the diagnosis of traumanic marrow edema. Methods Twenty-eight cases of traumanic marrow edema were found on MRI exam. Except routine SE T1WI?FSE T2WI and GE T2*WI, STIR sequence was performed.Results Thirty-six bone marrow edema were found in 28 cases, 24 lesions(67%)were all hypointensity on T1WI,12 lesions(33%)were depicted on T2WI, 8 lesions presented hypointensity and 4 mild hyperintensity. 29 lesions(80%)on T2*WI,14 were hypointensity and 15 hyperintensity. With STIR, 36 lesions(100%) displayed as hyperintensity signal more clearly.Conclusion STIR is good delineating traumanic marrow edema.

Objective To study the effects of lovastatin in the therapy of primary hypercholesterolemia on insulin sensitivity,vascular endothelial function and microcirculation in patients with coronary heart disease.Methods Forty-five patients,diagnosed as coronary heart disease and primary hypercholesterolemia,were treated by lovastatin for 8 weeks.Serum lipids,fasting plasma glucose (FPG),fasting insulin(FINS),nitric oxide(NO),endothelin(ET),6-keto-prostacyclin F 1?(6-keto-PGF 1?),thromboxane B 2(TXB 2) and nail-fold microcirculation (NFM) were measured and the score value of NFM and insulin sensitivity(IS) index were calculated in treatment group before and after 4-week and 8-week treatment with lovastatin.Forty healthy persons were taken as control.Results In treatment group,ET,TXB 2,and the score value of NFM were higher and NO,6-keto-PGF 1? and IS index were lower than those in control group.After 4-week lovastatin treatment,compared with baseline value,ET,TXB 2,and the score value of NFM significantly decreased,which were 63.19?18.72 vs 53.16?15.23 (P

AIM: To explore the feasibility of bone tissue regeneration guidance with the frozen heterogeneous periosteum. METHODS: The experiment was conducted in the animal laboratory of Beijing Shijitan Hospital from March to December 2002. ①Preparation of the frozen heterogeneous periosteum: The fresh pigs' cranial or rib bone periosteum was taken and washed with saline solution repeatedly, then defatted by immersion in 0.75 volume fraction alcohol, followed by frozen in the liquor of nitrogen for 10 minutes repeatedly for 3 times. After irradiated under ?-ray up to the amount of 3 kGy, the created membrane was placed in refrigerator for using. ②Surgical procedure: Two artificial mandibular bone defects were performed in 30 adult Japanese white big ear rabbits. One defect was covered with the created membrane as the experimental group, while another as the control group. ③Index observation: The rabbits were sacrificed after 2, 4, 8, 12, 16 weeks postoperatively for macroscopic, radiographic and histopathological observation. RESULTS: All 30 rabbits were involved in the result analysis. ①Macroscopic examination of the two groups: At the eighth week, guiding membrane was observed with irregular border. The experiment group was flat and stiff, while the control group was restored but with soft bone; at the twelfth week, the guiding membrane and surrounding border were unclear, but still could be observed. The newly bone of the experiment group was flat and stiff, while the control group was soft with hollow. ②Histopathological examination: At the eighth week, the new-formed bone in the margin of defect area of the experimental group grew intensively and the inflammatory cells in grafted membrane disappeared; intramembrane fiber was found oedema and broken; at the twelfth week, the trabecular bone of the experimental group was thick and arranged regularly. However, in the control group, the newly formed bone was little in the defect, and the trabecular bone was thinner compared with the experimental group. No evidence of inflammatory reactions was apparent, meanwhile the membrane degraded gradually. ③Radiograph examination: The bone density of the experimental group was greater than the control group at 4 and 8 weeks, and had no significant difference as to the vicinity bone at 12 and 16 weeks; on the other hand, the density of the control group was still lower. CONCLUSION: The frozen heterogeneous periosteum is a useful guiding membrane material for tissue regeneration, because it has no obvious rejection action in body, and could maintain its shape for 8-12 weeks, prevent the fiber tissue from growing into the wound surface, separate different cells and guide tissue regeneration.

Objective To summarize the observation points and nursing experience after minimally invasive ventriculo-atrial shunt. Methods 45 patients after minimally invasive ventficulo-atrial shunt were given preoperative psychological care and preparations, postoperative observation of vital signs, con-sciousness, pupil, with or without intracranial hypertension, inadequate shunt or transitional symptoms, in-fectious symptoms, specific and basic care, awareness of postoperative complications and detailed guidance for discharge and follow-up jobs. Results Half month after shunt 28 cases regained consciousness, 9 cases with alleviated consciousness dysfunction, 8 cases with unchanged consciousness dysfunction, 5 cases with shunt blockage; 3 cases with over-shunt; 5 cases with inadequate shunt, 1 case with blood-borne in-fection, 1 case with shunt exposed, no intracranial infection, air embolism, complications such as endocardi-tis took place. Conclusions Adequate preoperative preparation and close postoperative observation, ef-fective specific care and basic care can increase success rate of ventriculo-atrial shunt and improve the quality of life of patients.

Objective: To evaluate the biocompatibility of polymethylmethacrylate(PMMA) denture base resin containing silver-supported antimicrobial agent STR-1 of nanometer level in vitro. Methods: According to the national standards for biological evaluation of dental materials, the cytotoxicity of denture base resin containing STR-1 at concentrations of 5 g/L and 10 g/L was examined by molecular filtrating method, and the hemolysis of STR-1, denture base resin containing STR-1 at concentrations of 5 g/L and 10 g/L was also surveyed. Results: The control denture base resin without containing STR-1 and the denture base resins containing STR-1 at concentrations of 5 g/L and 10 g/L were not cytotoxic to L929 cells. Two hours and 24 hours after cell culturing, the filter membranes of the control and experimental groups were stained evenly with blue color. The staining intensity was not decreased and the fading areas were 0 mm~2 during the culturing. The cytotoxicity grades were 0. The hemolysis rates of the antimicrobial agent STR-1 and the denture base resins containing STR-1 at concentrations of 5 g/L and 10 g/L were 1.7%, 3.5% and 3.7% respectively. They were less than the national guild standard 5% which represent no hemolysis. Conclusion: The PMMA denture base resins containing silver-supported antimicrobial agents STR-1 of nanometer level at concentrations of 5 g/L and 10 g/L exhibit good biocompatibility.