Dental Pulp Diseases ; therapy ; Endodontics ; methods ; trends ; Humans

Objective:To investigate the patterns of microbial infection on the apical external root surfaces of treated and untreated teeth associated with chronic apical periodontitis and to study bacteria in the biofilm in order to find out the species,constitution and origination of bacteria in periapical biofilm.Methods: Ten teeth with chronic apical periodontitis from patients of the Department of Stomatology of People's Hospital,Peking University: 5 untreated teeth with a radiographically visible chronic periradi-cular lesions and 5 teeth with extensive carious lesions,radiolucent lesions of varying sizes and attached periradicular tissues were selected for study.Using aseptic techniques and sterile instruments,bacterial samples of the root canals were taken,inoculated and separated according to usual practice.After extraction,ten teeth were fixed and the apical 5 mm portion of one root was sectioned.Root tips were dehydrated,sputter coated with gold,and then examined for the occurrence of bacteria on the apical root surfaces using scanning electron microscope.Five healthy teeth with vital pulp were used as controls.Results: Microbial study showed that ten specimens yielded bacterial growth.The most prevalent bacteria were P.micros and F.nueleatum.In the 5 untreated teeth,bacterial cells were usually observed close to the apical foramen in only 1 specimen.Morphologically,these bacteria consisted of cocci.In the 5 treated teeth,a dense bacterial aggregation composed mainly of cocci and rods was observed surrounding the apical foramen of all specimens.Besides rods,other bacterial morphological types were recognized,including coaggregations of cocci and filaments,characterizing a fully developed "corn-cob".No microorga-nisms were found in the healthy controls.Conclusion:Bacterial biofilm was always present in teeth with post-treatment endodontic disease.The presence of apical bacterial biofilm is clinically important,and it may cause failure of endodontic treatment as a consequence of persistent infection.

Objective:To analyze the morphological characteristics of damaged Hero642 Ni-Ti dental files, and explain the relationship between deformation and fracture.Methods:71 discarded files were observed under naked eyes and stereomicroscope. 5 of which were observed under S360 scanning electronic microscope (SEM), and typical photos were taken for analysis.Results:The damage of Hero642 Ni-Ti dental files was characterized by fracture, tightened or loosened spiral and some kind of deformation detected at more than 35 times magnification. Under SEM, the dimple pattern was represented in the fracture surface of the files. Conclusion:Most Hero642 Ni-Ti files fractured within 4 mm from the tip which belongs to the pattern of ductile fracture.

Objective To determine the reliability of the tooth wear index in representing the profile of tooth cervical defect. Methods One hundred and ninety-three teeth with wedge-shaped defects were selected in 69 plaster casts. The sizes of every wedge-shaped defect were measured by using vernire caliper and the volumes of those were calculated. Otherwise, by weighting the restoration of defects, the real volumes of the 9 teeth defects were calculated by formulating. Results The formulation for calculatin of the real volume of the defects was presented as: volume = 0.4735 + 2.5948 X (deep of profile X height X broad of defects)/6. The profile of the defect was strongly related to the volume. Conclusions The value of one dimension measure of the wedge-shaped defects may present the tooth wear index.

Objective To understand the changes of allergic rhinitis from immunology,pathophysiology and morphology method were applied.Methods Toluene 2,4-diisocyanate was dissolved with florence oil to final concentration 10%,this solution was dropped into the nasal vestibules of animals to induce sensitization process.8 guinea pigs were prepared as allergic rhinitis with 10% Toluene 2,4-diisocyanate,and other 8 animals were used as blank controh.After model successfully established,the blood were obtained to determine RBC-C3b receptor rosette rate and RBC-imuuunocomplex rosette rate.The nasal mucosas were obtained from 2 groups,distribution and changes of substance P in nasal mucosa were observed with the application of immunohistochemical staining.The content of blood histamine was determined with ELASA method.The pathological changes of nasal mucosas were observed with the application of light microscope and transmission electron microscope.Results The behavior scores of the modeling animals were significantly higher than that of controls(P＜0.01).The value of RBC-C3b reeeptor rosette rate and RBC-imuuunoeomplex rosette rate of the modeling animals were significantly decreased than that of the controls(P＜0.05).Substance P presented in the normal nasal mucosal epithelial cells,epithelium cells of blood vessels,glandular cells and its duets,the staining density and the positive staining cells in the same aero in modeling group significantly increased,compared with controls.The counts of substance P-positive cells of control group were less than those of modeling group(P＜0.05).The content of blood histamine of the modeling animals were significantly increased compared with the controls(P＜0.01).The structure of false multiple coat cilium columnar epithelial cells in nasal mucosa of control group were successive,intact,and distinct.There were normal mucosal epithelium,lamina propria and submucosa.But modeling group showed that mucosal epithalamiums were damaged and shed,goblet cell proliferated,squamous metaphase,and epithelial necrosis happened,serous glands in lamina propria vigorously proliferated,blood vessels expanded,tissue edema formed,plenty of inflammatory cell such as eosinophil and mast cells were more in number and infiltrated.The structure of epithelial eells,cilia and mierotubule of nasal mucosa of control group were regular and distinct,there were abundant cellular organs in cytoplasm.Eosinophil cells were intact.But iu model group,mucosal epithalamium,cilia and its microtubule,mierovillus,goblet cell were damaged,the cell bulk and nucleus changed,mast cells and eosinophil cells changed,blood vessels expanded,serous glands vigorously proliferated.This morphological change was roughly identical to clinical manifestation of allergic rhinitis.Conclusion Toluene-2,4-diisocyanate can be used to establish allergic rhinitis model in guinea pigs,and some ehanges of the allergic rhinitis in model guinea pig were similar with clinic observation.

Objective To investigate the effects of shRNA interference (RNAi) targeting the histone lysine specific demethylase 1 (LSD1) on the proliferation and apoptosis in acute leukemia (AL) cells. Methods LSD1 shRNA vectors were constructed and transduced into HL-60 and SHI-1 AL cell lines. Inhibitory efficiency of LSD1 was detected by real-time quantitative PCR (RT-qPCR) and Western blot respectively. Cell proliferation was assessed by methyl thiazolyl tetrazolium (MTT), and cell apoptosis was measured by flow cytometry. Results After interference of LSD1, the expression levels of LSD1 mRNA and protein in HL-60 and SHI-1 cells (mRNA: 0.242 ±0.023, 0.207 ±0.006; Protein: 0.256 ±0.015, 0.486 ±0.042) were decreased compared with blank control group without transfection process (mRNA: 1.021 ±0.178, 1.039 ±0.395; Protein:0.552 ±0.026, 0.754 ±0.060) and empty vector negative control group (shNC group) (mRNA: 0.935 ±0.136, 1.016±0.203;Protein: 0.500±0.026, 0.750±0.049) (P<0.05). The levels of their cell proliferation (absorbance value: 0.712±0.010, 0.549±0.007) were inhibited compared with blank control group (absorbance value:0.823±0.010, 0.625±0.005) and shNC group(absorbance value: 0.818±0.019, 0.621±0.003) (P< 0.05). While cell apoptosis rates were increased [(32.80 ±1.35) %, (23.49 ±1.40) %] compared with blank control group [(8.08 ±0.62) %, (7.28 ±1.17) %] and shNC group [(8.08 ±0.62) %, (7.28 ±1.17) %] (P< 0.05). Conclusions Lentivirus-mediated shRNA interferencing LSD1 can inhibit cells ' proliferation and promote apoptosis of HL-60 and SHI-1 AL cell lines, indicating that LSD1 may be a potential biological molecular marker and a new treatment target for AL.

The military healthy information management system follows No.1,No.2 and No.3 military medical projects.This paper introduces the methods of revising receipt printing program in seven parts.

Objective To investigate the relationship between the helper T cell 17 (TH 17)/ Regulatory T cells (Treg cells) balance in peripheral blood with acute graft-versus-host reaction (aGVHD) after allogeneic hematopoietic stem cell transplantation (allo-HSCT),as well as the impact of anti-thymocyte immunoglobulin (ATG) on helper T cells in peripheral blood.Method Seventyeight hematologic patients underwent allo-HSCT,conditioning with or without ATG.Ten healthy volunteers severed as a control group.The helper T and regulatory T cells in peripheral blood were detected by flow cytometry.Enzyme-linked irnmunosorbent assay (ELISA) was used to detect serum concentrations of interleukin(IL)-17,IL-21,IL22,IL23,γ interferon (IFN-γ),and transforming growth factor β1 (TGF-β1).Result The percentage of Treg cells,TH17 cells and ratio of TH17/Treg cells in patients without aGVHD showed no significant difference from the healthy controls (P＞ 0.05).As compared with control group and non aGVHD group,the ratio of Treg cells was increased,the percentage of TH 17 cells,and TH 17/Treg cells were significantly increased in 1-2-degree aGVHD group (P＜0.01).With increased degree of aGVHD,the difference as above was more significant in 3-4-degree aGVHD recipients (P＜0.01).In aGVHD group,the IL-17,IL-23,IL-21 and IFN-γ concentrations were higher than the healthy group (P＜0.01) and non-aGVHD group (P＜0.05).Serum TGF-β1 level in aGVHD group was significantly decreased as compared with healthy group and non-GVHD group (P＜0.05),while IL-22 concentrations showed no statistically significant difference among three groups (P＞0.05).In anti-thymocyte immunoglobulin (ATG) pretreatment group,the absolute count of peripheral blood lymphocytes was less than in healthy control group (P＜0.01).In ATG group,the absolute counts of TH1 cells,TH17 cells,CD3+ CD4+ cells and non-TH1/17 cells were less than in non-ATG group (P =0.0000),while the absolute counts of lymphocytes,CD3+ CD4-cells,and TH 1/17 cells were less than in non-ATG group,but there was significant difference (P＞0.05).Conclusion The balance of TH 17/Treg cells and related cytokines were closely associated with aGVHD after allo-HSCT,and ATG influences the reconstruction of TH 17 and Th1 cells at early stage.

OBJECTIVE: To observe the clinical effect of perforated bovine amnion combined with recombinant bovine basic fibroblast growth factor (rb-bFGF) on degree Ⅱ burn wounds.METHODS: A total of 43 patients with small and medium-size thermal burn were collected, and the area of testing wound was 1% -2%. The wounds with the same nature were divided into three groups: perforated bovine amnion (treatment group), bovine amnion (control 1 group), and vaseline gauze dressing (control 2 group). All the three groups combined with rb-bFGF. RESULTS: Compared with control 1 group (P < 0.01) and control 2 group (P < 0.05), the treatment group could obviously decrease the healing time of deep degree Ⅱ burn wounds. For superficial degree Ⅱ burn wounds, compared with the control 2 group, the treatment group could also decrease the healing time; however, there was no significant difference between treatment group and control 1 group (P > 0.05). Dressing was not changed frequently, and the pain was relieved. Rash or other adverse effects were not detected in the three groups.CONCLUSION: The combination of perforated bovine amnion and rb-bFGF can obviously promote the healing of burn wounds.

OBJECTIVETo clinically investigate and identify the occlusal force as one of factors relative to formation of wedge-shaped defects.

METHODS123 subjects, selected from a group of middle-aged and elderly people in an urban area were divided into four groups: control, light, middle and severe group according to the severity of wedge-shaped defects. Cuspid, first and second premolars, and first molar in maxilla were examined for occlusal force by occlusometer, and the peak value of occlusal contact strain on every maxillary tooth was studied by photocclusion.

RESULTSSignificant reduce of occlusive force in the defected teeth was found than that of in the control teeth. The occlusal contact strain of first premolars with defects by photocclusion was statistically increased. The relative occlusal contact strain of first premolars and first molar of defects was higher than that of their proximate teeth.

CONCLUSIONOcclusal force could have relation to the formation of wedge-shaped defects.