BACKGROUND: Root canal files fracture is a kind of common oral clinical complications. Therefore, it is of clinical importance to study the cyclic fatigue of different types of stainless steel root canal files.OBJECTIVE: To explore the effect of the bending angle and cross-sectional area of root canal instruments on cyclic fatigue of stainless steel files.METHODS: Thirty 25# stainless steel K files (25 mm in length) were selected, the same to 30# and 35#. And these three kinds of files were respectively randomized into three groups (n=10 per subgroup). In the nine subgroups, the files were placed into self-made root canals at the bending angle of 45°, 60°, 90°, and driven by a 16:1 reducer (350 r/min).Fracture time in each subgroup was recorded and converted into the number of rotations. The microstructure of the fracture end of the files was observed under scanning electron microscope. Fractured files were collected and the crack tip length was measured by an electronic caliper.RESULTS AND CONCLUSION: At the same bending angle, the number of rotations resulting in file fracture was significantly reduced with the increasing of the cross-sectional area of the files (P < 0.05). When the type and cross-sectional area were same, the number of rotations resulting in file fracture was significantly reduced with the increasing of the bending angle of the root canals (P < 0.05), indicating a reduction in the cyclic fatigue performance of the files. Toughness fracture occurred in all the files, and circular or oval roughness nests with different sizes and microcavities formed on the fracture surface. In addition, brittle surfaces could be detective between the roughness nests. The diameter of roughness nests was gradually increased with the increasing of the bending angle of the root canals. For 30# and 35# files, the number of brittle surfaces was gradually increased with the increasing of the bending angle of the root canals. For 25# files, the crack tip length was gradually decreased with the increasing of the bending angle of the root canals, but there was no significant difference (P > 0.05). For 30# and 35# files, the crack tip length was significantly shortened with the increasing of the bending angle of the root canals (P < 0.05). But there were no significant changes in the 35#-60° and 35#-90° groups (P=0.095). At the same bending angle, there were no regular changes in the crack tip length in the different types of files. In conclusion, with the increasing of the cross-sectional area, the cyclic fatigue performance of the files with the same length and taper is reduced and the files become easy to be fractured; with the increasing of the bending angle of the root canals, the files with the same types are apt to be fractured near the root tip, indicating the shorter length of the crack tip indicates the more difficulty in the removal of the broken files.

Animals ; Cochlea ; pathology ; Female ; Guinea Pigs ; Hyperlipidemias ; pathology ; physiopathology ; Male ; Otoacoustic Emissions, Spontaneous

Objective To explore the value of the spectral CT iodine-based material decomposition technique in differential diagnosis of central pulmonary carcinoma from obstructive pneumonia and atelectasis.Methods 25 cases with central pulmonary carcinoma complicating with obstructive pneumonia and atelectasis underwent CT plain scan and spectral contrast scan including pulmonary-arterial-phase (PAP) and bronchial-arterial-phase(BAP).Conventional CT images and iodine base images were generated in each phase by GSI viewer.The 4 groups of images differences between the tumor and the obstructive pneumonia and atelectasis were analyzed.Results The margin of the tumor was ill-defined in plain scan.The cases that showed difference between the tumor and the obstructive pneumonia and atelectasis in 4 groups of images were respectively as follows,10 in conventional CT images of PAP,1 6 in conventional CT images of BAP,1 9 in iodine base images of PAP,and 23 in iodine base images of BAP.The difference of the 4 groups was significant (χ2 =16.54,P<0.05).There was the highest accuracy in iodine base images of BAP in defining the tumor margin (χ2 = 12.83,χ2 = 4.20,χ2 =1.34,P <0.05). The accuracy between conventional CT images of BAP and iodine base images of PAP had no significant differences (χ2 =0.86,P >0.05),but were better than that of the conventional CT images of PAP(χ2 =6.65,P <0.05).Conclusion Spectral CT iodine-based material decomposition technique is helpful to improve subjective diagnosis of central pulmonary carcinoma complicating with obstructive pneumonia and atelectasis,especially in iodine base images of BAP,it can provide accurate information for clinical stage and treatment.

Objective To study on the effectiveness of endoscopic ultrasonography(EUS)in detec- ting insulinoma preoperatively.Methods Fifteen patients with clinical and biochemical signs of insulinoma were examined by EUS using a radial-scanning ultrasound endoscope and abdominal ultrasonography,CT, DSA prior to surgery.The outcome was evaluated on the basis of surgery and examination of the resected specimens.Results Fifteen patients with 16 lesions of insulinoma were identified by surgery and pathology. The aceuraey of diagnosis with EUS was 13/15(86.7%),and that with B-US,CT,DSA was 3/15(20%), 5/15(33.3%),9/14(64.3%)respectively.In the 14 lesions identified by EUS,10 lesions were depicted to be hypoechogenic,1 lesion was isoechogenic and 3 lesions were hyperechogenie.All 14 lesions were well demarcated and surrounded by normal pancreatic tissue.The minimum size of the lesion visualized by EUS was 0.5cm.Ten lesions were correctly detected by EUS with size of 0.5～2.0cm.EUS missed diagnosis in 2 lesions not for their small size.EUS falsely indicated a 10mm lesion from two lesions inside the head of pancreas.One lesion outside the pancreatic tail and one lesion in the pancreatic head were missed by EUS in another case.Conclusion EUS is superior in assessing the location of pancreatic insulinoma than other ima- ging methods such as B-US,CT,DSA.

AIMTo investigate the protective effects of ginkgolide B and hypoxic preconditioning against acute hypoxia injury in mice.

METHODSOrdinary pressure acute hypoxia model in mice was adopted to observe the ethology, the duration of the death and the degree of brain edema. Meanwhile the expression of RTP801 mRNA and erythropoietin (EPO) were measured by RT-PCR and Western blot, respectively.

RESULTSGinkgolide B and hypoxic preconditioning could both prolong the survival time of hypoxia under ordinary pressure,and significantly decreased the degree of brain edema. Besides ginkgolide B and hypoxic preconditioning could both up-regulate the expression of RTP801mRNA and EPO.

CONCLUSIONGinkgolide B has the similar effect to hypoxic preconditioning against acute hypoxia. Both of these protective effects may be associated with the up-regulation of the expression of RTP801 mRNA and EPO.

Animals ; Brain ; metabolism ; Brain Edema ; prevention & control ; Erythropoietin ; metabolism ; Female ; Ginkgolides ; pharmacology ; Hypoxia ; physiopathology ; Ischemic Preconditioning ; methods ; Lactones ; pharmacology ; Male ; Mice ; Mice, Inbred ICR ; RNA, Messenger ; genetics ; metabolism ; Reperfusion Injury ; prevention & control ; Repressor Proteins ; genetics ; metabolism ; Up-Regulation ; drug effects

OBJECTIVETo investigate the effects of combined use of low-dose hydroxyurea (HU) and sodium butyrate (NaB) on the expression of 7 globin genes (zeta, alpha, epsilon, Ggamma, Agamma, delta, and beta) in human erythroid progenitor cells.

METHODSHuman erythroid progenitor cells were cultured using a two-step liquid culture system and treated with HU and NaB either alone or in combination. The inhibitory effects of the agents on the cell growth were monitored with trypan blue exclusion assay, and the changes in the mRNA of the 7 globin genes were detected using RT-PCR.

RESULTSLow-dose HU combined with NaB resulted in significantly lower inhibition rate of the erythroid progenitor cells than routine dose HU and NaB used alone (28.56% and 38.80%, respectively, P<0.05). Compared with untreated cells (0.653-/+0.092 and 0.515-/+0.048), HU combined with NaB significantly increased the expression of Ggamma-and Agamma- mRNA (1.203-/+0.018 and 0.915-/+0.088, respectively, P<0.05), and HU and NaB used alone produced similar effects (1.305-/+0.016 and 0.956-/+0.029 for HU, and 1.193-/+0.070 and 0.883-/+0.012 for NaB, P>0.05). HU and NaB, either used alone or in combination or at different doses, caused no significant changes in the other globin genes (zeta, alpha, epsilon, delta and beta) (P>0.05).

CONCLUSIONLow-dose HU combined with NaB can up-regulate gamma globin gene expression, especially Ggamma-mRNA expression, to decrease the growth inhibition on human erythroid progenitor cells in vitro, but produces no significant effect on the expressions of zeta, alpha, epsilon, delta and beta genes.

Anemia, Sickle Cell ; genetics ; Butyrates ; administration & dosage ; pharmacology ; therapeutic use ; Cells, Cultured ; Drug Therapy, Combination ; Erythroid Precursor Cells ; cytology ; drug effects ; physiology ; Erythropoiesis ; drug effects ; Humans ; Hydroxyurea ; administration & dosage ; pharmacology ; therapeutic use ; RNA, Messenger ; genetics ; metabolism ; gamma-Globins ; genetics ; metabolism

Objective:To make an assessment on the genotoxicity caused by black carbon ( BC ) and ozonized black carbon (O3-BC).Methods: In this study, 74 healthy male ICR mice [weighed (28 ± 1.5) g] were randomly divided into 7 groups, including one phosphate buffer solution ( PBS) control group and six particles exposed groups by intratracheal instillation with either BC or O 3-BC at the doses of 50, 100, 200 μg/mouse, respectively.There were 12 mice in the groups of 200μg/mouse and 10 mice in others.The mice were sacrificed 24 h after four intratrachealinstillations .The activities of catalase ( CAT) in serum and the levels of malondialdehyde ( MDA) in lung tissue homogenate were measured . As the DNA damage mark , 8-hydroxyguanosine ( 8-OHdG ) in urine and serum were quantified with ELISA method.Micronucleus test was used for potential genotoxicity of BC and O 3-BC.Hematoxylin and eosin staining was used to stain lung paraffin section .Results:The mice were in good condition during instillation , and the liver coefficient of the test groups was significantly lower than that of the control group (P<0.05).The activities of CAT in serum significantly increased in the 100 μg/mouse and 200μg/mouse groups after being exposed to these two kinds of particles .The micronucleus rate in allthe BC and O3-BC exposed groups increased ( P <0.05), but there was no statistically significant difference among the groups in the levels of 8-OHdG in serum and urine and MDA in lung tissue homogenate .In-flammatory response was found in the lung tissue under the microscope after exposure to BC and O 3-BC. Conclusion:Intratracheal instillation of BC and O 3-BC induced increasing of oxidative stress and genetic damage in mice .But there was no significant difference between these two particles in toxicity .Whether the genotoxicity of O 3-BC is higher than that of BC or not is uncertain .Further research is needed .

Objective To investigate clinical manifestation of unspecified functional bowel disorder (UFBD), the features of coexistence with functional gastrointestinal disorder (FGID) and its relationship with psychological factors and sleep disturbance in the Chinese Army servicemen.Methodsc FGIDs were diagnosed based on the RomeⅢ Modular Questionnaire. The subjects were 189 servicemen with UFBD (UFBD group) and 372 without FGID (control group). All subjects completed symptom checklist 90 (SCL-90) and Pittsburgh Sleep Quality Index (PSQI) questionnaire.Results'Have to rush to the toilet when having a desire to defecate' was the most frequent symptom of UFBD (93.7%). More than one half of UFBD patients had the symptom 'a feeling of incomplete emptying as bowel movements' or 'straining during bowel movements'. Twenty-eight percent of UFBD subjects had combined FGID (namely cFGID). Among them, the most frequent was proctalgia fugax (7.9%), followed by cyclic vomiting syndrome (6.3%), functional fecal incontinence (6.3%), functional dyspepsia (4.8%) and belching (4.8%). The UFBD group scored significantly higher than the control group in the global severity index (GSI) and in all SCL-90 subscales (P<0.05). The scores of the four domains (sleep quality, sleep latency , sleep disturbance and daytime function disorder), total PSQI score and proportion of poor sleeping quality were significantly higher in the UFBD group than in the control group (P<0.05). The subjects scored significantly higher in combined FGID group than in UFBD group in GSI and in all of SCL-90 subscales, except for phobic anxiety subscales (P<0.05). However, there was no significant difference in each domain, total PSQI and proportion of poor sleeping quality between the cFGID group and UFBD group (P>0.05).ConclusionPathogenesis of UFBD may be closely correlated with psychiatric and psychological factors and sleep disturbance. cFGID are associated with an increased severity of psychopathological features.

Objective To investigate the prevalence of mutation in the locus 306 of embB gene in multi-drug resistant (MDR) Mycobacterium tuberculosis (TB) and evaluate the prospects for using it as a molecular marker to detect MDR-TB.Methods The 291 strains enrolled in this study were from the reference laboratory of Shanghai municipal centers for disease control and prevention, all of which had been tested for drug susceptibility.Mutation in embB 306 was screened both by amplification refractory mutation system (ARMS) and DNA sequencing.The mutation frequencies of embB 306 in the sample groups varied in drug resistance were statistically analyzed.Results 38(51.4% ) of the 74 MDR-TB were embB 306-mutant (X2 =93.8,P＜0.01).Of the 24 TB resistant to at least two drugs but not MDR, 9(37.5% ) were embB 306 mutant (X2 =60.1 ,P＜0.01 ).But only two(4.9% ) embB 306-mutant strains were found in 41 strains resistant to only one drug (X2 =6.8,P=0.0093).None embB 306-mutant strains were found in 152 pansensitive strains.The specificity of using embB 306 as a molecular marker for detecting multi-drug resistant TB was 94.9% (206/217).Conclusions As a molecular marker for screening drug resistant TB,especially MDR-TB, the gene locus embB 306 shows a relatively high sensitivity and specificity, promising a sound future for its application in clinics to realize fast screening of patients infected with MDR-TB and to provide evidence for appropriate medication.

OBJECTIVETo analyze the differential proteomics in human umbilical cord mesenchymal stem cells (MSC) induced by chemical hypoxia-mimetic agent cobalt chloride (CoCl(2)) by two-dimensional gel electrophoresis (2-DE) and mass-spectrometry.

METHODS2-DE was performed to separate proteins from treated and untreated human umbilical cord MSC with CoCl(2). 2-DE images were analyzed by ImageMaster 2D Platinum software 6.0. The differential expressed proteins was identified by MALDI-TOF-MS. The differential proteins were classified based on their functions.

RESULTS2-DE reference patterns of CoCl(2) treated human umbilical cord MSC were established. A total of twenty-six differential proteins were identified, of them eleven proteins were up-regulated and fifteen down-regulated. Their biological functions involved in carbohydrate metabolism, protein metabolism and modification, lipid metabolism, coenzyme and prosthetic group metabolism, cell cycle, immunity and defense, cell structure and motility, signal transduction, protein targeting and localization, neuronal activities, muscle contraction, etc. Peroxiredoxin1 (Prdx) was down-regulated, whereas alpha-enolase (ENO1) and vesicle amine transport protein 1 homolog (VAT1) up-regulated.

CONCLUSIONThe effects of hypoxia on human umbilical cord MSC were participated by multiple proteins and involved in multiple functional pathways.

Cobalt ; pharmacology ; Humans ; Mesenchymal Stromal Cells ; drug effects ; metabolism ; Proteome ; analysis ; Proteomics ; Umbilical Cord ; cytology ; drug effects