Dental Pulp Diseases ; diagnosis ; therapy ; Humans ; Root Canal Therapy

Pulpitis and periapical periodontitis is a type of bacterial infectious disease, and bacteria frequently plant in the entire root canal system during the terminal stage. Main clinical treatment strategy of the disease requires root canal therapy, a key and core procedure for the successful treatment by thoroughly removing the root canal infection. The premise and guarantee of thoroughly removing root canal infection is by determining the accurate root canal working length. However, introduction of the complexity of the apical root anatomical structure, the confusion in determining the position of apical stop, and the method to determine the root canal working length. methods of accurately determining root canal working length, especially determining the position of apical stop, has been a hot topic among endodontic specialists, frequently causing confusion among many clinicians. This review provides a brief
Dental Pulp Cavity ; Periapical Periodontitis ; Pulpitis ; Root Canal Preparation ; Root Canal Therapy ; Tooth Root

Objective:To study the anatomy of the maxillary first permanent molars. Methods:Macrography was used to observe the morphology of the mesiobuccal root,the degree of abrasion,the morphology of the floor of pulp cavity, the number and type of apical foramen.Vernier was used to measure the length indexes and the distance from the apical foramen to the tip of the root.Clearing technique was used to investigate the root canal systems. Results:26.9% of mesiobuccal root had type III apical foramen,56.25% of mesiobuccal root had two canals,7.5% teeth had three root canals. Conclusions: The maxillary first permanent molar has a high ratio of more than one root canal in mesiobuccal root(63.75%).

Objective To investigate the effect of preoperative prophylactic parenteral nutrition on prognosis of advanced gastric cancer.Methods A total of 159 patients with advanced gastric cancer in our hospital were collected,and randomly divided into experimental group and control group.80 cases in experimental group were treated with prophylactic parenteral nutrition,and 79 cases in control group were treated with traditional nutrition.The partial indexes of liver function,complications and mortality rate were compared between the two groups before and after surgery.Results The levels of aspartate aminotransferase (AST),alanine aminotransferase (ALT),total bilirubin (TBIL) and direct bilirubin (DBIL) were much lower in experimental group than in control group at 8 days after surgery (t=6.542,6.460,5.634,5.275,all P＜0.001).The levels of ALB and PAB were much higher in experimental group than in control group at 2 and 8 days after surgery (t=12.580,12.471,6.757,12.821,all P＜0.001).The incidence of complications and mortality rate were much lower in experimental group than in control group (x2 =23.409,4.818,P＜0.001 or 0.05).Conclusions Preoperative prophylactic parenteral nutrition can speed up the recovery of liver function and reduce the complications and mortality rate after surgery in patients with advanced gastric cancer.

Objective To isolate and identify the Dengue virus(DEN)from the sera of patients with unknown fever in summer and autumn in Dushan and Xingyi areas of Guizhou province,China.Methods From June 2005 to October 2005.356 blood samples were collected from patients with unknown fever in Dushan and Xingyi areas of Guizhou province.The serum samples were inoculated on the C6/36 cell monolayers.After three blind passages,the cytopathie effect(CPE)Was observed.Identification of DEN antigen was earried out by indirect immunofluorescence assay(IFA)with the monoclonal antibody(McAb)against DENl-4 virus.The total RNA was extracted from the serum and tested by RT-PCR with the universal primer for DEN NS region.And determination of the RNA sequenee Was performed,and phylogenetic analysis was carried out.Results Three serum samples caused CPE and were proved as DEN2 positive by IFA,RT-PCR and senquence determination.The phylogenetic tree analysis showed that the isolated virus strains had the closest relations with the systemic evolution of the strains DEN2-43 and DEN2-44.Conclusion DEN infections exist in the population of Dushan and Xingyi of Guizhou,China.

Objective To evaluate the inhibitory effects of shRNAs targeting genes encoding viral capsomeres VP1-VP4 on enterovirus 71 (EV71) replication when used alone or in combination.Methods Short hairpin RNAs (shRNAs) targeting genes encoding VP1-VP4 protein of EV71 were designed and then respectively inserted into lentiviral vector pLKD-CMV-GFP-U6 to construct the recombinant plasmids.The expression plasmids together with psPAX2 and pMD2.G were transfected into 293T cells to induce the expression of recombinant lentiviruses,which were collected on the third day after transfection.The titers of recombined lentiviruses were determined by real-time PCR.The effects of shRNAs used alone or in combination on the expression of EV71 at mRNA and protein levels were respectively detected by real-time PCR and Western blot.Results The inhibitory effects of shRNAs on EV71 replication showed no significant differences among various strains (isolated from fatal cases,severe cases,mild cases and FY0805) (P＞0.05).Their inhibition rates were 51.6％ (sh-VP1-1),85.1％ (sh-VP1-2),76.4％ (sh-VP1-3),57.5％ (sh-VP2-1),81.4％ (sh-VP2-2),79.5％ (sh-VP2-3),68.9％ (sh-VP3) and 56.7％ (sh-VP4) respectively,and they were in a dosage dependent manner.sh-VP1-2 in combination with sh-VP2-2 showed the highest inhibition rate reaching up to 96.6％.Moreover,shRNAs used in combination showed better effects than any one used alone even at double dosage.Conclusion All shRNAs targeting viral capsid VP1-VP4 genes showed inhibitory effects on EV71 replication with inhibition rates over 50％ and the effects could be strengthened when using shRNAs in combination.

Objective To confirm the death of a child injured by a dog was due to rabies and to understand the molecular biologic features of rabies virus in Kaili,Guizhou province.Methods Brain tissue samples of patient and dog were collected to detect the rabies virus by direct immunofluorescence assay (DFA) and RT-nested PCR assay.Homology and phylogenetic tree were analyzed based on the whole nucleotide and deduced amino acid sequence of N gene of rabies virus followed by molecular epidemiological analysis.Results Both the human and dog brain tissue samples were confirmed positive by DFA and RT-nested PCR assay.The homology analysis of N gene sequences among GZH,GZD and other epidemic and vaccine rabies strains isolated from other provinces and other countries indicated that the detected samples shared the highest homology with the strain detected in Anlong prefecture in Guizhou in the year of 2006,and the homology between GZH and GZD was as high as 100％.Besides,among the vaccine strains,GZH and GZD showed the highest homology with strain CNT.Phylogenetic analysis indicated that the two samples were very close and belonged to genetype 1 lyssavirus,with the closest relationship between samples reported in Guizhou and Beijing.Conclusion It was confirmed on the viral molecular level that both the human and dog in Kaili were suffered from rabies,and the pathogens were genetype 1 lyssavirus.The prevalent strains in Kaili city was probably imported from other prefectures of Guizhou province,suggesting that prevention and control measures on rabies in Guizhou province should be strengthened.

Objective To investigate the effects of Leptospira interrogans ( L. interrogans) infec-tion on the activities of NADPH oxidase ( nicotinamide adenine dinucleotide phosphate-oxidase) and the lev-els of reactive oxygen species (ROS) in THP-1 and J774A. 1 cells and to understand the bactericidal mecha-nisms of macrophages in different hosts against L. interrogans. Methods Human mononuclear macrophage cell line (THP-1 cells) and murine mononuclear macrophage cell line (J774A. 1 cells) were infected with L. interrogans strain 56601. The activities of NADPH oxidase and the levels of superoxide ion ( O-2 ) were measured with spectrophotography. Changes in the levels of ROS were detected with immunofluorescence as-say. Results Compared with the normal cells, the activities of NADPH oxidase in L. interrogans-infected J774A. 1 cells changed from 0. 619 0 μmol · min-1 · mg-1 to 0. 305 5 μmol · min-1 · mg-1 , 6. 141 5μmol·min-1 ·mg-1 , 1. 487 1μmol·min-1 ·mg-1 and 0. 964 6μmol·min-1 ·mg-1 after 2, 4, 12 and 24 hours of infection, respectively (P<0. 05), while the activities of NADPH oxidase in L. interrogans-infected THP-1 cells were up-regulated from 0. 723 5μmol·min-1 ·mg-1 to 0. 884 2μmol·min-1 ·mg-1 , 1. 897 1μmol·min-1 ·mg-1 , 1. 125 4 μmol·min-1 ·mg-1 and 0. 562 7 μmol·min-1 ·mg-1 , respectively ( P<0. 05). The levels of O-2 in L. interrogans-infected J774A. 1 cells at the time points of 2 h, 4 h, 12 h and 24 h after infection increased from 0. 189 0μmol/L to 0. 236 3μmol/L, 0. 297 7μmol/L, 0. 324 0μmol/L and 0. 305 7 μmol/L, respectively (P<0. 05), while the levels of O-2 in L. interrogans-infected THP-1 cells rose from 0. 123 7 μmol/L to 0. 149 3 μmol/ L, 0. 249 0 μmol/ L, 0. 270 0 μmol/ L and 0. 272 7μmol/L, respectively (P<0. 05). The fluorescence intensity of ROS in THP-1 and J774A. 1 cells increased gradually after infection with L. interrogans for 2 h and decreased after reaching the peak at 24 h. Conclu-sion Both the activities of NADPH oxidase and the levels of O-2 in J774A. 1 and THP-1 cells were signifi-cantly upregulated after infected with L. interrogans, especially in J774A. 1 cells. The results of this study provided references for further elucidating the bactericidal mechanisms of macrophages in different hosts against L. interrogans.

Objective To analyze the effects of Leptospira interrogans ( L. interrogans) infection on the activation of NLRP3 in THP-1 and J774A. 1 cells and to further understand the mechanism of inflam-mation caused by L. interrogans in different hosts. Methods Human mononuclear macrophage cell line (THP-1) and murine mononuclear macrophage cell line (J774A. 1) were infected with L. interrogans strain 56601. The expression of NLRP3 at mRNA and protein levels were measured by using real-time RT-PCR and flow cytometry analysis, respectively. The NLRP3-mediated secretion of IL-1β, IL-18 and IL-33 was detec-ted by ELISA combined with the NLRP3 inhibitory test. Results Compared with the normal cells, the ex-pression of NLRP3 at mRNA level in L. interrogans-infected THP-1 cells was respectively increased by 4. 05, 0. 34, 0. 33, 0. 06 and 1. 66 times at the time points of 1 h, 2 h, 4 h, 12 h and 24 h after infection ( P<0. 05), while that in L. interrogans-infected J774A. 1 cells was respectively increased by 12. 98, 16. 19, 10. 68, 5. 8 and 0. 57 times (P<0. 05). The expression rates of NLRP3 protein in THP-1 and J774A. 1 cells respectively increased from 9. 26% to 94. 01%, 89. 24%, 31. 80%, 19. 74%, 11. 28% and from 18. 71%to 58. 78%, 43. 64%, 36. 42%, 76. 46%, 85. 21% at the time points of 1 h, 2 h, 4 h, 12 h and 24 h af-ter L. interrogans infection (P<0. 05). The level of IL-1β in L. interrogans-infected THP-1 cells was 73. 07 pg/ml, 939. 24 pg/ml, 939. 24 pg/ml, 843. 22 pg/ml and 851. 06 pg/ml at the time points of 1 h, 2 h, 4 h, 12 h and 24 h, respectively (P<0. 05), while the level of IL-1β in L. interrogans-infected J774A. 1 cells began to rise at the time point of 12 h from 191. 17 pg/ml to 254. 4 pg/mL at the time point of 24 h (P<0. 05). The level of IL-18 in L. interrogans-infected THP-1 cells was 913. 89 pg/ml, 808. 19 pg/ml, 483. 54 pg/ml, 204. 19 pg/ml and 189. 09 pg/ml at the time points of 1 h, 2 h, 4 h, 12 h and 24 h, re-spectively (P<0. 05), while the level of IL-18 in L. interrogans-infected J774A. 1 cells increased at the time point of 24 h, which was 113. 37 pg/ml (P<0. 05). A slight increase in the level of IL-33 was detected in L. interrogans-infected J774A. 1 cells at the time points of 12 h and 24 h to 201. 14 pg/ml and 155. 68 pg/ml, respectively (P<0. 05), but no significant change was detected in L. interrogans-infected THP-1 cells (P>0. 05). Results of the inhibitory test showed that the up-regulation of IL-1β , IL-18 and IL-33 in THP-1 and J774A. 1 cells were effectively inhibited by the specific inhibitor of NLRP3. Conclusion NL-RP3 inflammasome was activated and involved in the production of specific inflammatory cytokines IL-1βand IL-18 in both THP-1 and J774A. 1 cells after L. interrogans infection, but the inflammatory cytokines induced by L. interrogans infection varied in different cells. L. interrogans induced earlier and higher level of IL-1βand IL-18 production in human macrophages than in murine macrophages.

Objective To investigate the expression of inducible nitric oxide synthase ( iNOS) and the levels of nitric oxide (NO) in THP-1 and J774A. 1 cells during Leptospira interrogans (L. interrogans) infection for a better understanding of the mechanism of macrophages involved defense against L. interrogans strains in different hosts. Methods The human mononuclear macrophages (THP-1) and the murine mono-nuclear macrophages (J774A. 1) were infected with L. interrogans strain 56601. The expression of iNOS at mRNA and protein levels were determined by using real-time RT-PCR and flow cytometry analysis. The lev-els of NO were detected with Griess test. Results The expression of iNOS at mRNA level in J774A. 1 and THP-1 cells infected with L. interrogans strains for 2, 4, 12 and 24 hours were respectively 1. 37, 2. 82, 25. 76, 27. 47 times and 1. 59, 3. 98, 3. 89, 8. 81 times than that of cells without infection (P<0. 05). The expression rates of iNOS protein in J774A. 1 cells were increased from 34. 16% to 85. 85%, 93. 82%, 91. 77% and 93. 65% along with the increased time of infection time (P<0. 05). The expression rates of iNOS protein in THP-1 cells were up-regulated from 22. 08% to 72. 64%, 81. 33%, 80. 03% and 65. 72%after 2, 4, 12 and 24 hours of infection (P<0. 05), respectively. Results of the Griess test indicated that the levels of NO in J774A. 1 and THP-1 cells were respectively increased from 0. 1588 μmol/L to 0. 2208μmol/L, 0. 2668μmol/L, 0. 3808μmol/L, 0. 3828μmol/L and from 0. 0988μmol/L to 0. 2848μmol/L,0. 3228 μmol/L, 0. 2608μmol/L and 0. 3308μmol/L after infection with L. interrogans strains for 2, 4, 12 and 24 hours (P<0. 05). Conclusion The expression of iNOS and the levels of NO in J774A. 1 and THP-1 cells were significantly increased during L. interrogans infection. This study might help to explain the bactericidal mechanism of macrophages derived from different hosts against L. interrogans infection.