Objective:To discuss the possibility of modifying nonfunctional distractors to improve the quality of multiple-choice questions in medical examination through analyzing the changes in the difficulty and discrimination of items and the selection rate of modified distractors.Methods:Thirty-two multiple-choice questions involving nonfunctional distractors from a medical examination were studied. According to the item-writing guidelines, experts modified nonfunctional distractors based on actual measurements. We analyzed the changes in the difficulty and discrimination of items and the selection rate of modified distractors before and after item modification using the paired Wilcoxon test, and investigated the correlation of item difficulty and discrimination before and after item modification by Spearman's rank correlation analysis.Results:Six questions were modified due to technical factors, and 26 questions were modified due to weak interference in knowledge content. Before and after nonfunctional distractor modification, the difficulty values of the questions were 0.676 (0.558, 0.893) and 0.637 (0.531, 0.839), respectively; the discrimination values (point-biserial correlation) were 0.261 (0.150, 0.316) and 0.262 (0.138, 0.358), respectively; and the discrimination index values were 0.215 (0.113, 0.352) and 0.259 (0.138, 0.346), respectively. There were significant differences in the difficulty and discrimination index of items before and after modification. The difficulty and discrimination of items before and after modification were both significantly correlated. The selection rates of modified distractors were 0.009 (0.003, 0.015) and 0.044 (0.021, 0.092) before and after modification, respectively, which were significantly different.Conclusions:Nonfunctional distractors in this study were mainly caused by reasons in the contents of the test questions, less in technical defects. Through the analysis and modification of nonfunctional distractors, the selection rate of nonfunctional distractors can be effectively increased, and item difficulty and discrimination can be improved.

Objective: To establish a method for simultaneous determination of calceolarioside B and chlorogenic acid in Caulis Stauntoniae Chinensis tablets by HPLC.
Methods: The analysis was performed on a Thermo BDS HYPERSIL C₁₈ column (4.6 mm×250 mm,5 μm) maintained at 35 ℃. The mobile phase was consisted of methanol and 0.1% phosphoric acid solution, and gradient eluted with a flow rate of 1.0 mL·min^-1. The detection wavelength was 327 nm, and the injection volume was 10 μL.
Results: The linear ranges of calceolarioside B and chlorogenic acid were 0.51-20.60 μg·mL^-1 (r=1.000) and 0.52-20.63 μg·mL^-1 (r=1.000), respectively. The average recoveries were 100.3% with RSD as 1.1% and 105.9% with RSD as 1.4%, respectively. The content results of 5 batches of Caulis Stauntoniae Chinensis tablets were 0.083-1.115 mg·g^-1 for calceolarioside B and 0.161-1.204 mg·g^-1 for chlorogenic acid.
Conclusion: The method can be used for improving the quality evaluation standard of Caulis Stauntoniae Chinensis tablets.

Objective:To realize a fully automated synthesis of 11C-meta-hydroxyephedrine (mHED) and to perform imaging studies with it. Methods:11C-mHED was prepared by the 11CH 3-triflate method. The crude product was purified by semi-preparative high performance liquid chromatograph (HPLC) to obtain the final product. The radiochemical purity and specific activity were determined by radio-HPLC. The myocardial uptake and excretion process of the agent were monitored by microPET/CT imaging on 5 normal SD rats. The clinical imaging value was evaluated using PET/CT imaging in a patient (male, 42 years old) with myocardial infarction. Results:The automated synthesis of 11C-mHED was realized by a commercial synthesizer. The total synthesis time was about 30 min. The radiochemical yield was (15±2)% (non-decay corrected, n=10) and the radiochemical purity was greater than 98%. The specific activity was about 65 GBq/mmol. MicroPET/CT imaging in normal SD rats showed the myocardial uptake was highest at 10 min after the injection of imaging agent, and then the imaging agent was gradually excreted from the myocardium through the liver and gallbladder. PET/CT imaging of a patient with myocardial infarction showed an imaging agent defect near the apex in the inferior wall of the left ventricle, which was matched with results of ultrasound and electrocardiogram examination. Conclusions:11C-mHED can be successfully prepared automatically, with high radiochemical yield and specific activity. It can also highly concentrate in the myocardium, and the imaging effect with this agent is good in a patient with myocardial infarction.

Objective:To compare the quantitative parameters of myocardial blood flow based on SPECT imaging and those determined by PET imaging in coronary microvascular disease (CMVD) animal models, in order to clarify the accuracy and feasibility of SPECT quantitative analysis in CMVD.Methods:Seven Saanen milk goats (either male or female; (20±5) kg), were selected for establishing CMVD animal models by microsphere embolization. Dynamic myocardial perfusion imaging (DMPI) with one-day method of resting + ATP stress 99Tc m-methoxyisobutylisonitrile (MIBI) SPECT was performed before and after the modeling, respectively. One-day method of resting + ATP stress 13N-ammonia PET DMPI was performed after the modeling. The quantitative parameters determined by SPECT and PET after the modeling, including stress myocardial blood flow (SMBF), resting myocardial blood flow (RMBF) and myocardial flow reserve (MFR), were compared by paired t test. Parameters based on SPECT after modeling were compared with those of baseline levels. Bland-Altman analysis was applied to access the agreement between SPECT and PET. Results:Four of the seven experimental goats were fully imaged. The RMBF(ml·g -1·min -1; 1.52±0.27 vs 1.29±0.20), SMBF(ml·g -1·min -1; 0.74±0.19 vs 0.99±0.26), and MFR (0.53±0.16 vs 0.76±0.10) of the left ventricle (global) obtained by SPECT and PET in CMVD models were not significantly different ( t values: 3.121, 1.195, 1.930, all P>0.05). Among left anterior descending branch (LAD), left circumflex (LCX) and right coronary artery (RCA), the RMBF, SMBF and MFR values quantified by SPECT and PET were neither statistically significant ( t values: 0.182-2.734, all P>0.05). Bland-Altman analysis showed the quantitative parameters measured by SPECT and PET DMPI in left ventricle, LAD, LCX, RCA had a good consistency. The difference between the two methods for determining RMBF was up to 0.63 ml·g -1·min -1, and that of SMBF was up to 0.66 ml·g -1·min -1. All points are within the 95% confidence limit; MFR differs at most by 0.56, and 14/16 points were within 95% confidence limit. The RMBF (ml·g -1·min -1) of left ventricle measured by SPECT after modeling was not significantly different from that before modeling (1.52±0.27 vs 1.57±0.36; t=0.166, P>0.05); the SMBF (ml·g -1·min -1) and MFR after modeling were significantly lower than those before modeling (0.74±0.19 vs 2.34±0.89, 0.53±0.16 vs 1.39±0.31, t values: 3.836, 6.309, both P<0.05). Similar results were found when comparing the parameters of LAD/LCX/RCA after modeling with those before modeling (RMBF t values: 0.191, 0.235, 0.195, all P>0.05; SMBF/MFR t values: 0.411-19.911, all P<0.05). Conclusion:The blood flow quantitative parameters measured by SPECT imaging have a good consistency with those based on PET imaging, and the myocardial blood flow quantitative analysis of SPECT can evaluate the blood flow perfusion of CMVD.

Objective In a large-scale clinical medical examination, A2 type best multiple-choice test questions to the same knowledge were used respectively in simple and complex form, to compare the difficulty and discrimination indices of the two forms of test questions and provide evidence to the improve-ment of clinical medical examination. Method In a large-scale clinical medical examination more than 4000 candidates participated, and 20 questions to different knowledge points were randomly selected and used in the examination respectively in simple and complex A2 type best multiple-choice test questions. The difficulty and discrimination indices of the two forms of test questions were compared. Results The average difficulty coefficient of the 20 simple test questions (65.5 words per question in average) is 0.6829, and the average discriminative powers are 0.2675 and 0.2579 respectively using identification index method and point biserial correlation method. The average difficulty coefficient of the 20 complex test ques-tions (135.5 words per question in average) is 0.7095, and the average discriminative powers are 0.3065 and 0.2967 respectively using identification index method and point biserial correlation method. Conclusion To the same knowledge points, the average difficulty of complex A2 type best multiple-choice test questions is slightly lower than the simple ones, while the average discriminative power is increased in the complex questions. The complex A2 type test questions are of higher quality and more in line with the requirements of the medical entrance examination, medical education and examination reform.

Objective To evaluate 11C-MDA,a cardiac sympathetic nerve presynaptic molecular probe,in acute myocardial ischemia (AMI) and to compare with 13N-Ammonia myocardial perfusion imaging.Methods Twelve Bama miniature pigs were used to establish AMI models.11C-MDA and 13N-Ammonia PET/CT were performed before and after model establishment.The defect fraction,ratio of defect to normal region,defect volume of 11C-MDA and 13N-Ammonia PET/CT were calculated.Paired-t test and twosample t test were used.Results Eight models were established successfully and 4 pigs died.The defect fractions on 11C-MDA and 13N-Ammonia myocardial imaging were significantly different (13.4±3.3 vs 7.4±1.0,18.8±4.4 vs 4.8±1.0,10.5±4.2 vs 4.4±0.9;t values:4.901,8.864,4.030,all P＜0.001) at the first,third and sixth month post-model establishment.The ratios of defect to normal region on 11C-MDA and 13N-Ammonia PET/CT myocardial images were significantly different (0.47±0.14 vs 0.59±0.10,0.43±0.13 vs 0.61±0.09;t values:-2.166,-3.415,both P＜0.05) at the first and third month post-model establishment.The defect volumes on 11C-MDA and 13N-Ammonia PET/CT were significantly different ((4.20±0.34) vs (2.55±0.11) cm3,(10.66±0.71) vs (2.46±0.12) cm3,(5.95±0.50) vs (2.44±0.11) cm3;t values:12.925,32.149,19.440,all P＜0.001) at the first,third and sixth month post-model establishment.Conclusions Myocardial ischemia-reperfusion and cardiac sympathetic restoration might occur at different times.The recovery of myocardial ischemia-reperfusion is earlier than that of the cardiac sympathetic nerve.

This paper summarizes the clinical diagnosis and treatment of imported African schistosomiasis,in order to make the therapeutic standards. Imported African schistosomiasis includes mainly schistosomiasis haematobia and schistosomiasis mansoni in China. In order to set up the operational standards,enhance diagnostic and cure rates,and reduce the complica?tions,we review the related literature combined with our experience over years,and summarize,in this paper,the pathogenic mechanism,and key points of clinical diagnosis and treatment of schistosomiasis haematobia and schistosomiasis mansoni,so as to provide the reference for clinical doctors.

The medical assistance to advanced schistosomiasis patients established by the Chinese government is a major public facility for patients with advanced schistosomiasis. Since the medical assistance to advance schistosomiasis patients in Hu?nan Province started ten years ago,a set of mature and operable programs with whole program management and related technolo?gies has been developed. The author investigated the data on medical assistance to advanced schistosomiasis patients in Hunan Province during the last 10 years(from 2006 to 2015)retrospectively,and found that the program had high therapeutic effect and high satisfaction degree of both patients and the society. In order to improve the management of the medical assistance to ad?vanced schistosomiasis patients and share our experiences of the whole program management and related technologies with the colleagues of other provinces,this paper mainly illustrates the experiences of the program,as well as the existing problems and related strategies.

Objective To study the anatomic features of surface vasa vasorum on longissimus in thoracolumbar segments,and its protection function during the internal fixation for thoracolumbar fracture via Wiltse approach.Methods From March 2010 to October 2012,a total of 97 patients with thoracolumbar fractures underwent posterior internal fixation with pedicle screw system.The trend and distribution of surface vasa vasorum on longissimus in thoracolumbar segments were observed in the operation,and the vessels were protected during the surgical procedures by using specific devices and techniques.Operative time and intra-operative blood loss were recorded.Visual analogue scale (VAS) values were evaluated after 3 days,1 month,6 months postoperatively,and 1 month after the removal of internal fixation.MRI images of longissimus in thoracolumbar segments were compared after preoperative and postoperative 6 months.Results Surface vasa vasorum distribution on 194 longissimus and 402 inter-pedicle areas of 97 patients were observed.In 402 areas,94.3％ of surface vasa vasorum presented sarciniform,while only 5.7％ of surface vasa vasorum presented tube shape.In 379 areas of sarciniform distribution,9.8％ of blood vessel bundles were located in vertebral pedicle area;76.0％ of blood vessel bundles were located in the upper inter-pedicle areas;12.4％ of blood vessel bundles were located in middle inter-pedicle areas;1.8％ of blood vessel bundles were located in lower inter-pedicle areas.In 379 areas,87.3％ of blood vessel bundles could be completely retained;12.7％ of blood vessel bundles were treated by electro coagulation and burning.Intra-operative blood loss was 21±9.3 ml.VAS values after 3 days,1 month,6 months postoperatively,and 1 month after the removal of internal fixation were 3.3± 1.6,2.1± 1.4,1.2±0.7 and 1.1±0.7.The longissimus treated with electro coagulation demonstrated pimelosis change on MRI after postoperative 6 months.Conclusion Surface vasa vasorum on longissimus in thoracolumbar segments are generally of sarciniform,and most of them are located in upper inter-pedicle areas.The protection of vasa vasorum can reduce the intra-operative lesion and postoperative pimelosis change of longissimus.

Objective To study the effect of precise locating technique of C?arm fluoroscopy in order to reduce the radia?tion exposure during the surgical procdure for thoracolumbar fracture. Methods From March 2010 to Octorber 2012, a total of 92 cases with thoracolumbar fracture underwent postierior internal fixation procdures with pedicle instrumentation. C?arm fluoros?copy was used in 44 cases with precise locating technique, while in 48 cases with traditional methods. In precise locating group,C?arm fluoroscopy was used after anesthesia. Once an ideal view was got, the position parameters of C?arm fluoroscopy machine were recorded. The machine was positioned according to the recording for the secondary fluoroscopy. Pre?operative and intra?operative number of times of exposure, length of exposure time, time for fluoroscopy and total operating time were recorded and compared be?tween two groups. Results Pre?operative number of times of exposure, exposure time, and time for fluoroscopy in precise locating group were (5.51±2.47), (2.26±1.05) s and (9.83±3.67) min,which were higher than those of (4.02±2.42), (1.78±0.98) s and (8.29± 3.52) min in traditional group. However, intra?operative number of times of exposure, exposure time, and time for fluoroscopy in precise locating group were (5.26±3.64), (2.24±1.24) s and (10.39±4.82) min,which were lower than those of (9.74±4.38), (4.21± 2.38) s and (24.69±6.35) min in traditional group,and total number of times of exposure, exposure time, time for fluoroscopy and total operating time in precise locating group were(10.77±4.16), (4.50±1.83) s, (20.22±5.03) min and(70.52±18.33)min,which were also lower than those of (13.76±5.31), (5.99±3.27) s , (32.98±7.83) min and(81.86±21.57)min in traditional group. Conclu?sion Precise locating technique of C?arm fluoroscopy reduces the radiation exposure during the surgical procdure for thoracolum?bar fracture.