Objective To evaluate the efficacy of high performance liquid chromatography (HPLC) for simultaneous determination of propofol and remifentanil concentrations in human plasma.Methods Methods Eighteen healthy volunteers of both sexes,aged 18-45 yr,weighing 52-81 kg,were enrolled in the study.Venous blood samples were collected,and the concentrations of propofol and remifentanil in human plasma were detected simultaneously by HPLC.The internal standard was thymol.Potassium dihydrogen phosphate 0.1 mol/L was added to the plasma and then the plasma samples were extracted with extract liquor (ethyl acetate ∶ hexane =4 ∶ 1,V/V).The analytical column was ZORBAX Eclipse XDB-C18 (4.6 mm×250 mm,5 μm).The mobile phase was methano ∶ 0.02 mol/L NaH2PO4 ∶ acetonitrile,the flow rate was 1.0 ml/min,the detection wavelength was 210 nm within 1-7 min,and 266 nm within 7-16 min,and the sample size was 20 μl.Linear regression analysis was performed by using the least-squares method.The specimens of the blood with the final concentration of remifentanil 1.00,5.00 and 20.00 ng/ml and propofol 0.50,2.00 and 10.00 μg/ml were obtained to determine the recovery,precision and stability.Results Linear regression equation of remifentanil was C=12.853 5Ai/As+0.084 8 (R2 =0.999 4),and this system showed a good linear relationship with the concentration of remifentanil ranged 0.5-40.0 ng/ml.Linear regression equation of propofol was C=8.554 3 Ai/As+0.029 1 (R2=0.998 6),and this system showed a good linear relationship with the concentration of propofol ranged 0.2-20.0 μg/ml.For both propofol and remifentanil concentrations,the relative recovery was within the range of 85％-115％,the absolute recovery was larger than 75％,and the relative standard deviation of intra-and inter-day precision and stability was less than 5％.The method was proved to meet the requirements of biological sample analysis.Conclusion For HPLC method established in this trial,the determination is sensitive,reproducible,rapid and simple,and it can be used for simultaneous determination of propofol and remifentanil concentrations in human plasma and for clinical pharmacokinetic research.

Objective To investigate status and risk factors of drug resistance of smear-positive pulmonary tuber-culosis (TB)patients in Hunan Province,and provide reference for the prevention and control of drug-resistant TB. Methods 1 935 Mycobacterium tuberculosis (MT)complex strains identified by 20 TB prevention and control insti-tutes in Hunan Province between 2012 and 2014 were collected and performed drug susceptibility testing,and influ-encing factors associated with drug resistance of TB were analyzed statistically.Results Of 1 935 MT complex strains,1 207 (62.38%)were sensitive to 6 kinds of antituberculosis drugs,728 were drug-resistant strains,overall drug resistance rate was 37.62%;467 (24.13%)were multidrug-resistant (MDR)strains,64 of which were exten-sively drug-resistant (XDR)strains,XDR rate was 3.31 %,resistance rates from high to low were as follows:isoniazid(INH)29.32%,rifampicin(RFP)25.84%,streptomycin(SM)20.73%,thambutol(EMB)9.00%,ofloxa-cin(OFX)7.83%,and kanamycin(KM)2.21 %.Multivariate logistic regression analysis showed that patients hav-ing a history of treatment,aged 20-39 and 40-60 years old were risk factors for drug resistance and MDR of pul-monary TB.Among patients who failed in retreatment,OR (95% CI )of resistance to INH,RFP,SM,EMB, OFX,KM,and MDR were 13.5(9.9-18.4),21 .2(15.2-29.5),5.3(3.9-7.2),11 .9(7.6-18.7),7.6(4.6-12.6),7.9(3.6-17.5),and 25.0(17.7-35.1 )respectively;among patients who had recurrence,OR(95% CI ) of resistance to INH,RFP,SM,EMB,OFX,and MDR were 7.4(5.5 -10.0),10.3 (7.4 -14.2),3.5 (2.5 -4.8),7.3(4.5 -11 .9),4.1 (2.5 -6.8),and 12.2(8.7 -17.1 )respectively;among patients who failed in initial treatment,OR (95% CI )of resistance to INH,RFP,SM,EMB,and MDR were 7.6 (4.7 - 12.3 ),9.8 (5.9 -16.0),4.1(2.5-6.8),12.1(6.5-22.7),and 11 .4(6.9-18.9)respectively.Among patients aged 20-39 years old,OR (95% CI )of resistance to INH,RFP,SM,and MDR were 2.5 (1 .8 -3.4),3.6(2.5 -5.2),2.9(2.0-4.1),and 4.1(2.8 -6.1 )respectively;among patients aged 40 -60 years old,the OR (95% CI )of resistance to INH,RFP,SM,and MDR were 2.2(1 .6-3.0),3.1(2.2-4.4),2.3(1 .6-3.2),and 3.3(2.3 -4.7)respectively. Conclusion Drug resistance of smear-positive pulmonary TB patients is serious in Hunan Province,patients receiv-ing anti-tuberculosis treatment and aged between 20-60 years old have high risk for drug resistance and MDR.

Objective To evaluate the efficacy of superficial temporal artery(STA)pressure-guided selective cerebral perfusion(SCP)during deep hypothermic circulatory arrest(DHCA)in patients undergoing aortic arch surgery.Methods Ninety-six patients of both sexes,aged 35-64 yr,with body mass index of 19-23kg/m2,of American Society of Anesthesiologists physical status Ⅲ or Ⅳ,undergoing aortic arch surgery,were divided into STA pressure group(group A)and clinical experience group(group B)using a random number table,with 48 patients in each group.In group A,STA catheterization was performed after tracheal intubation,and arterial pressure was monitored.SCP flow was adjusted to maintain the target value of STA pressure between 30 and 40mmHg during DHCA in group A.SCP flow rate was set at 5-10ml·kg-1·min-1 according to clinical experience in group B.The volume of fluid perfused during SCP,emergence time,extubation time and duration of intensive care unit stay were recorded.Neurological function was evaluated during length of hospitalization after surgery,and the development of permanent and transient neurological dysfunction and mortality in hospital were recorded.Results Compared with group B,the volume of fluid perfused during SCP was significantly decreased,the emergence time,extubation time and duration of intensive care unit stay were shortened,the incidence of permanent and transient neurological dysfunction(2% and 4%,respectively)was decreased(P < 0.05),and no significant change was found in the mortality rate in hospital in group A(P>0.05).Conclusion Maintaining STA pressure at 30-40mmHg is a reliable method for guiding SCP during DHCA in patients undergoing aortic arch surgery.

Objective To investigate the risk factors for myocardial injury after Nano-Knife surgery in patients with pancreatic cancer, and to establish a nomogram model for risk prediction. Methods A retrospective analysis was performed for the clinical data of 92 patients with pancreatic cancer who underwent Nano-Knife surgery in The Fifth Affiliated Hospital of Zhengzhou University from September 2020 to November 2021, with serum cardiac troponin I > 0.03 ng/mL within 3 days after surgery as the diagnostic criteria for myocardial injury, the patients were divided into myocardial injury group with 51 patients and non-myocardial injury group with 41 patients. Related baseline data were collected for all patients, including age, sex, body mass index, American Society of Anesthesiologists classification, smoking history, alcohol abuse history, and preoperative comorbidities. The Mann-Whitney U test was used for comparison of continuous data between groups, and the chi-square test or the Fisher's exact test was used for comparison of categorical data between groups. Univariate and multivariate logistic regression analyses were used to screen out the variables with statistical significance, and the factors screened out were used to establish a nomogram for predicting the risk of myocardial injury after Nano-Knife surgery in patients with pancreatic cancer. The receiver operating characteristic (ROC) curve and the area under the ROC curve (AUC) were used to evaluate the discriminatory ability and clinical utility of the model. Results Compared with the non-myocardial injury group, the myocardial injury group had a significantly longer ablation time ( χ 2 =7.410, P =0.006), a significantly greater number of probes ( χ 2 =6.130, P =0.047), and a significantly higher proportion of patients with preoperative hypertension ( χ 2 =12.124, P < 0.001) or chronic kidney disease ( χ 2 =12.829, P < 0.001). The univariate logistic regression analysis showed that tumor diameter, ablation time, surgical procedure, number of probes, history of hypertension, and history of chronic kidney disease were associated with the development of myocardial injury (all P < 0.05), and the multivariate logistic regression analysis showed that tumor diameter (odds ratio [ OR ]= 3.94, 95% confidence interval [ CI ]: 1.09-14.18, P =0.036), ablation time ( OR =4.15, 95% CI : 1.30-13.27, P =0.016), surgical procedure ( OR =6.92, 95% CI : 1.92-25.07, P =0.003), and history of hypertension ( OR =4.07, 95%CI: 1.12-14.77, P =0.034) were independent risk factors for myocardial injury after Nano-Knife surgery in patients with pancreatic cancer. An AUC of 0.859 showed that the nomogram had good discriminatory ability and clinical utility. Conclusion There is a relatively high incidence rate of myocardial injury after Nano-Knife surgery in patients with pancreatic cancer. Preoperative hypertension, tumor diameter > 4 cm, and ablation time > 1 hour are independent risk factors for myocardial injury, and the surgical procedure of Nano-Knife surgery and bypass anastomosis can increase the risk of myocardial injury. The nomogram has a good effect in predicting the risk of myocardial injury.

BACKGROUNDThe Xpert MTB/RIF showed high sensitivity and specificity in previous studies carried out in different epidemiological and geographical settings and patient populations in high-burden tuberculosis (TB) countries. However, there were little data obtained by validation or demonstration study of the assay in China. In this study, the performance of Xpert MTB/RIF was investigated in two county-level laboratories in Hunan Province, China.

METHODSConsecutive patients with suspected pulmonary tuberculosis (PTB) and suspicion for multidrug-resistant tuberculosis (MDR-TB) were enrolled. For each patient suspected to have PTB, three sputum specimens (one spot sputum, one night sputum, and one morning sputum) were collected and each sputum was tested with smear microscopy, Löwenstein-Jensen (LJ) culture, and Xpert MTB/RIF test. For comparison across subgroups and testing methods, 95% confidence intervals were calculated. All analyses were done with SPSS 16.0, and P < 0.05 was regarded as significant.

RESULTSFor case detection, the sensitivity of Xpert MTB/RIF was 100% for smear- and culture-positive TB and 88.6% for smear-negative and culture-positive TB; the overall sensitivity was 94.5% for all culture-positive patients. The specificity was 99.8%. The sensitivity of Xpert MTB/RIF assay was 22.0% in clinical TB patients and the specificity reached 100.0% in the group of patients who are infected with nontuberculous mycobacteria. For the detection of rifampin resistance, the sensitivity of MTB/RIF RIF-resistance detection was 92.9%, and the specificity was 98.7%. Of the 26 Xpert MTB/RIF-positive and RIF-resistant patients confirmed by LJ proportion tests, 20 (76.9%) patients were infected by MDR-TB.

CONCLUSIONSThe Xpert MTB/RIF assay is a highly sensitive and specific method for diagnosis of TB and RIF resistance, which will enable it to have the potential to be used in county-level laboratories and lead to the reduction of the infectious pool and improvements in TB control in China. Further evaluations in county-level laboratories for implementing the assay are still required.

Adult ; Antibiotics, Antitubercular ; therapeutic use ; China ; Female ; Humans ; Male ; Middle Aged ; Rifampin ; therapeutic use ; Tuberculosis ; diagnosis ; drug therapy ; Tuberculosis, Multidrug-Resistant ; Tuberculosis, Pulmonary ; diagnosis ; drug therapy ; Young Adult