Objective: To examine the microbial flora within the root canals with failed root canal therapy by PCR test, to identify detection rate of bacteria and the predominant bacteria species, and to determine the association of the various species with clinical features. Methods: Forty roots with failed root canal therapy were selected for this study. According to clinical features the roots were divided into three groups: pain, fistula and symptomless. After removal of the root filling material, the microbial samples were taken from the canal and detected by PCR test. Results: The microbial flora within root canals of teeth with failed root canal therapy was found to be mixed, six kinds of bacteria were detected. Enterococcus faecalis was the most commonly recovered bacteria species. Significant associations were observed between Prevotella nigrescens and pain, while dependablity was observed between Actinomyces israelii and fistula. Conclusion: The main cause of root canal treatment failure is the persistent microorganisms. The composition of bacteria in teeth with failed root canal therapy has its own specificity.

Objective To study the changes and significance of CD4+CD25+ regulatory T cells and C-reactive protein(CRP) in patients with acute exacerbation of chronic obstructive pulmonary disease(COPD). Methods Flow cytometry was used to detect the frequency of CD4+CD25+ regulatory T cells in peripheral blood from 36 patients with acute exacerbation of COPD( COPD group) and 36 patients with clinical stability of COPD(control group one)and 36 normal individuals(control group two). The level of CRP was detected routinely. Results The ratio of CD4+CD25+ regulatory T cells number in peripheral blood of COPD group to the total number of CD4+T cell was (2.56±1.83 )%, and it was significantly decreased compared to the other two groups (P all<0.01 ). The level of CRP in COPD group was markedly higher than that in the other two groups (P all<0.01 ). The level of CD4+CD25+ regulatory T cells in patients with acute exacerbation of COPD had negative relation with CRP. Conclusions CD4+CD25+ regulatory T cells participate in inflammatory response. The proportion of CD4+CD25+ regulatory T cells decreases in patients with acute exacerbation of COPD, and it may result in maladjustment of cytoimmunity.

Objective:To analyze the factors related to the duration of chest compression pause time during the manual-mechanical conversion process in cardiopulmonary resuscitation (CRP).Methods:A retrospective study was devised in a cohort comprising patients with out-of-hospital cardiac arrest, who were assigned to receive mechanical CRP in the Department of Emergency of Huzhou First People's Hospital from January 2019 to December 2020. Patient’s general characteristics, CRP data and data on CRP-free intervals were collected multiple linear regression to analyze associations with the duration of chest compression pause time during the manual-mechanical conversion process in CRP. At the same time, the effect of CPR treatment qualification of nurses on CPR compression quality was evaluated.Results:The study selected 32 eligible patients. Patient's height, actual body weight, and body mass index showed a positive liner correlation with the duration of chest compression pause time ( r=0.61, 0.92, 0.49; P<0.01). Multiple stepwise regression analysis showed that actual body weight was an independent risk factor for prolonged duration of chest compression pause time ( P<0.01). Moreover, responsible nurses with advanced cardiac life support (ACLS) certification had significantly higher compression scores than those without ACLS certification (χ 2=0.002, P<0.01). Conclusions:The actual body weight of patients and the ACLS qualification of nurses on duty have a certain relationship with the duration of chest compression pause time during the manual-mechanical conversion process in CRP, which is worthy of further research.

Objective:To analyze the changes rule of serum procalcitonin (PCT) levels in patients with traumatic brain injury in plateau areas, and to evaluate its value in assessing the severity and prognosis of the patients.Methods:A prospective cohort study was conducted. The patients with traumatic brain injury admitted to the critical care medicine departments of Xining Third People's Hospital (at an altitude of 2 260 metres) and Golmud City People's Hospital (at an altitude of 2 780 metres) from May 2018 to September 2022 were enrolled. According to the Glasgow coma scale (GCS) score at admission, the patients were divided into mild injury group (GCS score 13-15), severe injury group (GCS score 9-12), and critical injury group (GCS score 3-8). All patients received active treatment. Chemiluminescence immunoassay was used to measure the serum PCT levels of patients on the 1st, 3rd, 5th, and 7th day of admission. The Kendall tau-b correlation method was used to analyze the correlation between serum PCT levels at different time points and the severity of the disease. The patients were followed up until October 30, 2022. The prognosis of the patients was collected. The baseline data of patients with different prognosis were compared. The Cox regression method was used to analyze the relationship between baseline data, serum PCT levels at different time points and prognosis. Receiver operator characteristic curve (ROC curve) was drawn to analyze the predictive value of serum PCT levels at different time points for death during follow-up.Results:Finally, a total of 120 patients with traumatic brain injury were enrolled, including 52 cases in the mild injury group, 40 cases in the severe injury group, and 28 cases in the critical injury group. The serum PCT levels of patients in the mild injury group showed a continuous downward trend with the prolongation of admission time. The serum PCT levels in the severe injury and critical injury groups reached their peak at 3 days after admission, and were significantly higher than those in the mild injury group (μg/L: 3.53±0.68, 4.47±0.63 vs. 0.40±0.14, both P < 0.05), gradually decreasing thereafter, but still significantly higher than the mild injured group at 7 days. Kendall tau-b correlation analysis showed that there was a significant positive correlation between serum PCT levels on days 1, 3, 5, and 7 of admission and the severity of disease ( r value was 0.801, 0.808, 0.766, 0.528, respectively, all P < 0.01). As of October 30, 2022, 92 out of 120 patients with traumatic brain injury survived and 28 died, with a mortality of 23.33%. Compared with the survival group, the GCS score, serum interleukin-6 (IL-6) levels, white blood cell count (WBC) in peripheral blood, and PCT levels in cerebrospinal fluid at admission in the death group were significantly increased [GCS score: 5.20±0.82 vs. 4.35±0.93, IL-6 (ng/L): 1.63±0.45 vs. 0.95±0.27, blood WBC (×10 9/L): 14.31±2.03 vs. 11.95±1.98, PCT in cerebrospinal fluid (μg/L): 11.30±1.21 vs. 3.02±0.68, all P < 0.01]. The serum PCT levels of patients in the survival group showed a continuous downward trend with prolonged admission time. The serum PCT level in the death group peaked at 3 days after admission and was significantly higher than that in the survival group (μg/L: 4.11±0.62 vs. 0.52±0.13, P < 0.01), gradually decreasing thereafter, but still significantly higher than the survival group at 7 days. Cox regression analysis showed that serum IL-6 levels [hazard ratio ( HR) = 17.347, 95% confidence interval (95% CI) was 5.874-51.232], WBC in peripheral blood ( HR = 1.383, 95% CI was 1.125-1.700), PCT levels in cerebrospinal fluid ( HR = 1.952, 95% CI was 1.535-2.482) at admission and serum PCT levels on admission days 1, 3, 5, and 7 [ HR (95% CI) was 6.776 (1.844-24.906), 1.840 (1.069-3.165), 3.447 (1.284-9.254), and 6.666 (1.214-36.618), respectively] were independent risk factors for death during follow-up in patients with traumatic brain injury (all P < 0.05). ROC curve analysis showed that the AUC of serum PCT levels on days 1, 3, 5, and 7 for predicting death during follow-up in patients with traumatic brain injury was all > 0.8 [AUC (95% CI) was 0.898 (0.821-0.975), 0.800 (0.701-0.899), 0.899 (0.828-0.970), 0.865 (0.773-0.958), respectively], indicating ideal predictive value. The optimal cut-off value for serum PCT level at 3 days of admission was 1.88 μg/L, with the sensitivity of 78.6% and specificity of 88.0% for predicting death during follow-up. Conclusions:Abnormal expression of serum PCT levels in patients with traumatic brain injury on the 3rd day of admission was found. The serum PCT levels greater than 3 μg/L may be related to severe illness. The serum PCT levels greater than 1.88 μg/L can predict the poor prognosis of patients. Dynamic observation of changes in serum PCT levels has good evaluation value for the severity and prognosis of patients with traumatic brain injury in plateau areas.