Objective:To establish a method for the simultaneous determination of 8 heavy metal elements Pb, Cd, As, Hg, Co, V, Se and Mo in iron dextran by inductively coupled plasma optical emission spectrometry ( ICP-OES) . Methods:Through the detec-tion wavelength selection,the detection wavelength was confirmed as follows:220. 353 nm for Pb, 228. 802 nm for Cd, 188. 980 nm for As, 194. 164 nm for Hg, 228. 615 nm for Co, 311. 070 nm for V, 196. 026 nm for Se and 204. 598 nm for Mo. Through optimizing the instrument parameters, the optimal radio frequency power was 1. 3 kW, the nebulizer gas flow rate was 0. 7 L·min-1, and the pump speed was 10 r·min-1. By applying the above detection parameters, the 8 heavy metal elements were analyzed by ICP-OES simultaneously. Results: The linearity of the detected elements was good, and the correlation coefficients were all greater than 0. 9990. The detection limits were from 0. 12 to 7. 26 ng·ml-1 , the quantitation limits were from 0. 40 to 23. 96 ng·ml-1 and the recoveries were from 94. 1% to 103. 4% (RSD<3%, n=9). Conclusion: The method is specific, sensitive, rapid and accurate, which can be applied in the simultaneous determination of 8 heavy metal elements in iron dextran.

Background and objective Small cell lung cancer (SCLC) accounts for nearly 15% of all cases of can-cer. As a type of highly invasive tumors, SCLC has high degree of malignancy, early and extensive metastasis, and is sensitive to chemotherapy and radiotherapy. The early treatment response rate of SCLC is high but it can also relapse rapidly without any treatment. Its median survival time is merely four to six months. Although many studies on SCLC have been conducted in re-cent years, its clinical treatment strategies have remained unchanged. The treatment of SCLC is still confined to chemotherapy regimens of etoposide plus cisplatin (EP) and other classic treatments because the surgical treatment of SCLC, particularly for Ⅲa treatment, has yet to reach a consensus. This study investigated the prognostic factors and clinical therapy effect in the comprehensive treatment of Ⅲa SCLC after surgical treatment.Methods This study was conducted through the retrospective analysis of the clinical data of 78 patients with SCLC who underwent surgical treatment in Beijing Chest Hospital affiliated to Capital Medical University between January 1995 and December 1995. Through follow-up, we performed statistical analysis of each patient's gender, age, tumor size, lymph node metastasis, tumor-node-metastasis (TNM) staging, surgical methods, and adjuvant radiation and chemotherapy.Results The median survival in this clinical trial team was 13.93 months. Among the participants, 47 patients accepted neoadjuvant chemotherapy and their median survival were 14.25 months. By contrast, 31 patients accepted postoperative adjuvant chemotherapy and their median survival were 13.83 months. No statistical difference was observed between the two groups. Moreover, 28 patients were of single Lymph node metastasis and their median survival was 17.1 months. By contrast, 50 patients were of multiple lymph node metastasis and their median survival was 11.9 months. Significant statistical difference was observed between the two groups (P<0.01).Conclusion In performing further evalua-tion of the status and value of surgical treatment in the comprehensive treatment of SCLC, several patients benefitted from Ⅲa SCLC surgery with comprehensive treatment.

【Objective】 To analyze the effect of different range and location of foramen formation on the biomechanics of lumbar spine by three-dimensional finite element analysis （D-FEA）. 【Methods】 A complete model of the lumbar spine （L5）， M0， was developed using the finite element method， and the models M1， M2， M3， M4 and M5 were obtained by sequentially simulating the apical， medial 1/4， 2/4， 3/4 and 4/4 graded resections of the left superior articular process of L5 under a lateral posterior approach with full spinal endoscopy. The displacements were recorded in six conditions： forward flexion， back extension， left and right lateral bending， and left and right lateral rotation. The results were compared between the resected models and the unresected group M0. 【Results】 The three-dimensional finite model of the L4-L5 segment developed in this experiment was valid. Compared with the unresected group M0， the differences in ROM were statistically significant for M1 under forward flexion load （all P<0.05）， M2 under forward flexion and back extension load （all P<0.05）， M3 and M4 under forward flexion， back extension and left and right lateral bending load （all P<0.05）. The differences were statistically significant for M3 and M4 under anterior flexion， posterior extension， left and right lateral flexion， and right rotation loads （all P<0.05）； and for M5 under anterior flexion， posterior extension， left and right lateral flexion and right rotation loads （all P<0.05）. Compared with M0 in the unresected group， the differences were statistically significant for M1 under anterior flexion loads （all P<0.05）， M2 under anterior flexion and left and right rotation loads （all P<0.05）. The differences were statistically significant for M3， M4 and M5 in forward flexion and extension， left and right lateral flexion， and left and right rotational loading （all P<0.05）. 【Conclusion】 In the process of foramen formation， removal of the tip or the medial quarter of the unilateral single segment of the upper articular process of the lumbar spine will affect the stability of the lumbar spine， and increase the maximum value of the stress of the intervertebral disc during the activities of the lumbar spine. Removal of one half or more will significantly damage the biomechanics of the lumbar spine. In order to avoid damaging the normal biomechanics of the lumbar spine， the upper articular process should be protected as much as possible during the whole spinal endoscopic foraminal reconstruction.

【Objective】 To observe the short-term clinical effect of selective nerve block combined with percutaneous posterior endoscopic cervical discectomy （PPECD） in the treatment of cervical spondylotic radiculopathy. 【Methods】 We reviewed 22 patients who received selective nerve block combined with percutaneous posterior endoscopic cervical discectomy （PPECD） for cervical spondylotic radiculopathy from June 2018 to January 2020. We recorded Japanese Orthopaedic Association （JOA） score for treatment evaluation， visual analogue scale （VAS）， the neck disability index score （NDI） preoperative 1 day， postoperative 1 day， 1 month， 3 months， 6 months and 1 year. All data were imported into SPSS26.0 software for analysis and processing. Quantitative data are expressed as mean ± standard deviation. The scores of neck VAS， arm VAS， JOA and NDI were compared at different time points by repeated measurement analysis of variance. Paired t-test was used to compare each time point after operation and the first day before operation. P<0.05 was considered statistically significant， and the modified MacNab standard was used to evaluate the clinical effect at the last follow-up. 【Results】 All operations were successfully completed under ultrasound-guided selective nerve block combined with endoscopic operation. The average operation time was 125.6 minutes. The intraoperative blood loss was 2-100 mL and the average blood loss was 19.1 mL. All patients were followed up for 15-33 months， with an average follow-up of 24.1 months. No patients had spinal cord， nerve root and vascular injury， dural tear or other complications. Compared with the preoperative VAS score， the VAS score of neck and upper arm decreased significantly （P<0.05）， while the JOA score increased significantly （P<0.05）， and the preoperative NDI score decreased significantly （P<0.05）. At the last follow-up， the modified Macnab criteria showed there were 15 excellent cases， 5 good cases， 2 medium cases and 0 poor case. The excellence rate was 91%. Postoperative magnetic resonance imaging and 3D computed tomography reconstruction of the cervical spine showed that the disc had been fully removed and the nerve root compression at the surgical segment was relieved. 【Conclusion】 Ultrasound-guided selective nerve block combined with percutaneous posterior endoscopic cervical discectomy is a safe and effective minimally invasive surgical method for the treatment of cervical spondylotic radiculopathy with reliable short-term efficacy.