In order to analyze the association of the periodontitis severity withchanges of the human dental pulp, one hundred caries-free and restoration-free periodontallyinvolved teeth with different periodontic destruction were studied histologically. It wasfound that there was correlation between the severity of periodontitis and changes in thehuman dental pulp. The incidence of pulpal pathosis rose as the periodontic destructionbecame severe. Pulpal inflammation was related to periodontitis, but not to the severityof periodontitis. Pulpal necrosis was mostly found in the teeth with advanced periodonti-tis.

AIM: To study the possible role of nitric oxide (NO) in the development of periodontitis and the relationship between the NO concentration and the attachment loss. METHODS: Seventy- two Sprngue- Dawley rats were randomly assigned to two groups, the control group and periodontitis group. Experimental periodontitis in rats was produced by a ligature of braided silk. The nitric oxide concentration was indirectly ascertained by the concentration of nitrite (NO2-) and nitrate (NO3-)in the gingival tissue, which was assayed by spectrophotometry. The attachment loss (AL) was measured by the technology of the cellular graphics engineering research. The histopathologic change in periodontium was observed under a light microscope by using the histotomy. RESULTS: Compared to control group, the NO2-/NO3 - concentration in gingival tissue was significantly higher in periodontitis group at four weeks and eight weeks following ligation (P＜0.01). In periodontitis group, the NO2-/NO3 - concentration in gingival tissue was higher at eight weeks than that at four weeks following ligation (P＜0.01). At four weeks and eight weeks, the AL in experimental periodontitis in rats was significantly increased than that at one week after ligation ( P＜0.01); and the AL was also much higher at eight weeks than that at four weeks (P＜0.01). CONCLUSIONS: The NO2-/NO3- concentration in the gingival tissue in periodontitis group was significantly higher than that in control group. These results demonstrate that the NO2-/NO3- concentration is related to the severity of AL, and NO synthesis is very important to the process of inflammation and lesion in periodontium. Reducing NO production may be of great therapeutic value in the treatment of periodontitis.

AIM: To study the inhibitory effect of aminoguanidine(AG) on periodontitis. METHODS: Experimental periodontitis was produced in rats by a ligature of braided silk, the NO concentration was assayed by spectrophototometry, the attachment loss of periodontium was measured by using technology for image and graphics engineering research and the histopathologic changes of periodontium were also examined under a light microscope. RESULTS: The NO concentration significantly decreased after AG treatment for 4 weeks, and the inflammation and the damages of periodontium was also reduced significantly. CONCLUSION: The inhibition of iNOS by AG may be a potential therapeutic strategy for the treatment of periodontitis.

AIM: To observe the effect of mineral trioxide aggregate (MTA) combined with fibronectin as pulp capping agents. METHODS: The 48 pulps of 4 cats were exposed mechanically and then capped directly with MTA, MTA combined with fibronectin, calcium hydroxide, fibronectin and starch as control. After 12 weeks observation, the experimental teeth were extracted and observed with scanning electronic microscope. RESULTS: In calcium hydroxide group and MTA group, specimens showed irregular dentin bridge structures along the pulp-MTA interface. In MTA combined with fibronectin group, continuous and complete dentin bridge structures were found along the pulp-MTA interface, the crystalline-like structures were in direct contact with the dentin wall of pulp chamber, the exposed pulp sites were closed by the dentin bridge. In fibronectin and starch group, no reparative dentin was observed. CONCLUSION: The present experiment indicated that MTA combined with fibronectin was an effective pulp-capping material and may have potential for clinical application. [

AIM: To study the effect of local application of indomethacin on acute pulpitis. METHODS: Traumatic pulpitis model in rats was established by means of pulp exposure, radioimmunoassay (RIA) was used to measure the kinetic changes of the levels of PGE_2、6-keto-PGF_~1? and TXB_2 of pulpal tissues. RESULTS: Local application of indomethacin could more effectively inhibit the cyclo-oxygenase pathway than zinc oxide engenol in the early stage of pulpitis and reduce the production of prostaglandins. CONCLUSION: Local application of indomethacin may have a therapeutic effect on acute pulpitis. [

Objective To study the clinical features of pulmonary Langerhans cell histiocytosis.Methods Restrospectively review of 7 cases of pulmonary Langerhans cell histiocytosis proved by pathology with the clinical,physical,radiological,pathological and pulmonary function presentation.Results Seven cases were all male,aged from 17 to 37.Four of them are cigarette smokers.The major symptoms were cough and laboring dyspnea,and pneumothorax presented in five cases.As to pulmonary function presentation,obstructive pattern presented in three cases,restrictive pattern and mixed pattern presented in two cases respectively,and the carbon monoxide diffusing capacity was decreased in four cases.The abnormalities present predominantly in the upper and middle lung fields on chest high-resolution CT scan.Lung cysts and reticular changes presented in six cases and nodules presented only in one case.The diagnosis was established by surgical lung biopsy.The positive cases of staining for the S-100,CD1a antigens,and CD68 were 7/7,4/5 and 5/6 respectively.Conclusion PLCH patients are typically young adults,often present with cough,laboring dyspnea and pneumothorax.Pulmonary function presentation is nonspecific and the carbon monoxide diffusing capacity may be decreased.The characteristic features of HRCT are bilateral reticulonodular areas and cysts change that predominantly involved the upper and middle lung zones with relative sparing of the lung bases.The pathologic feathers are interstitial infiltration of bronchiole walls and epithelium by LCH cells and cyst formation.The staining for CD1a antigens and the S-100 proteins is positive by immunohistochemical analysis.

AIM: To investigate the titer and avidity of serum immunoglobulin G (IgG) antibody for surface antigens of Porphyromonas gingivalis (P. gingivalis) in sera from patients with early-onset periodontitis (EOP) and evaluate the interrelationship of the antibody titer and avidity. METHODS: 15 patients with early-onset periodontitis, 16 patients with adult periodontitis(AP) and 14 periodontally healthy subjects(HS) participated in this study. Levels and avidities of IgG antibody against P.gingivalis lipopolysaccharide(LPS) were measured. Serum IgG titers against P.gingivalis antigens were measured by enzyme-linked immunosorbent assay (ELISA). IgG avidity was measured by diethylamine dissociation ELISA. RESULTS: Serum IgG antibody levels against P.gingivalis LPS in EOP and AP patients were significantly higher than that of healthy subjects (P0.05). Antibody avidities to P. gingivalis in EOP were significantly higher than that of AP patients and HS group (P0.05). CONCLUSION: These results indicate that there is no correlation between antibody levels and avidities in EOP and AP patients. IgG avidity can be considered as a valuable parameter in the diagnosis of EOP.

Objective To establish a simplified amplification method for obtaining a large number of purified Cryptosporidium parvum oocysts from infected C57BL/6N mice. Methods All mice in the experimental groups were immunosuppressed by given different concentrations of dexamethasone phosphate added in drinking water throughout the experiment. The recovery and purity of the oocysts obtained using different purification methods was compared. The infectivity of the oocysts obtained from the same origin but different animals and different purification methods in a bovine fallopian tube epithelial cell culture system was studied. Results 4.16?10 9 oocysts were obtained in 30 mice in the 3rd group with dexamethasone of 20 ?g/ml in drinking water. No significant difference in the oocyst recovery, purity and infectivity was found between methods using saturated saline floatation and sucrose density gradient centrifugation. The infectivity of the oocysts obtained from the same origin but different animals was similar. Conclusion A simplified amplification method for obtaining a large number of purified Cryptosporidium parvum oocysts from the infected mice was established.

AIM: The purpose of this study was to investigate the role of interleukin-4 (IL-4) in the development of periodontitis in mice by low dosage of Trichinella spiralis (T. spiralis) infection.METHODS: Twenty-seven male Kunming mice in specific pathogen free grade were randomly divided into three groups: (1) the normal control group;(2) the experimental periodontitis group, which was produced by ligature of braided silk around the first maxillary molar, and was inoculated with putative periodontopathic bacteria;(3) the periodontitis with T. spiralis infection group. The mice were sacrificed at the end of 1, 3 and 5 weeks. The probing depth (PD) was measured before the mice were euthanized. The histological change of periodontal tissues was observed under the microscope after the samples were stained with hematoxylin and eosin. Furthermore, the serum level of IL-4 was determined by ELISA. RESULTS: (1) The serum level of IL-4 in T. spiralis-infected group was significantly higher than that in experimental periodontitis group (P<0.01). (2) The PD in T. spiralis-infected group was significantly lower than that in experimental periodontitis group (P<0.01). (3) Only a mild inflammatory response was observed in T. spiralis-infected animals. CONCLUSION: T. spiralis infection upregulates IL-4 expression and attenuates periodontitis in mice.

AIM: To evaluate the effect of mechanical periodontal treatment combined with tetracycline on per iodontal attachment level (AL) and the avidity of serum antibody against porphyromonas gingivalis( P. gingivalis) in patients with aggressive periodontitis(AgP). METHODS: Twenty- five patients with AgP and twenty periodontally healthy controls were studied (HS). Clinical examination and recordings of AL were performed before and 3,6 and 12 months after the periodontal treatment. The avidity of IgG antibody against P. gingivalis lipopolysaccharide(LPS) was measured by diethylamine dissociation ELISA. RESULTS: A significant improvement in AL was observed following treatment ( P ＜ 0. 01 ). The avidity of serum IgG antibody against P. gingivalis increased compared with controls, and was decreased significantly after mechanical periodontal treatment combined with tetracycline (P ＜ 0. 01 ). CONCLUSION: Ourresults demonstrate that mechanical periodontal treatment combined with tetracycline provides clinically favorable results in patients with AgP.