More than 70%of tumor patients require radiotherapy.Medical electron linear accelerators are important high-end radiotherapy equipment for tumor radiotherapy.With the application of artificial intelligence technology in medical electron linear accelerator,radiotherapy has evolved from ordinary radiotherapy to today's intelligent radiotherapy.This study introduces the development history,working principles and system composition of medical electron linear accelerators.It outlines the key technologies for improving the performance of medical linear electron accelerators,including beam control,multi-leaf collimator,guiding technology and dose evaluation.It also looks forward to the development trend of major radiotherapy technologies,such as biological guided radiotherapy,FLASH radiotherapy and intelligent radiotherapy,which provides references for the development of medical electron linear accelerators.

Objective:To investigate the analgesic effect of ultrasound-guided quadratus lumborum block at the lateral supra arcuate ligament (LSQLB) and subcostal transversus abdominis plane block (TAPB) for open liver surgery.Methods:Forty-two patients who underwent elective open liver surgery in Lishui Central Hospital from February 2021 to October 2021 were randomly divided into two groups: LSQLB group (L group, n=21) and TAPB group (T group, n=21). Both groups underwent preoperative ultrasound-guided nerve block, and then LSQLB in group L and subcostal TAPB under the right costal margin in group T. The surgery was subsequently completed under general anesthesia. Patient controlled intravenous analgesia (PCIA) was performed in both groups. The mean arterial pressure (MAP) and heart rate (HR) before skin cutting (T 0), immediately after skin cutting (T 1), at the time of liver exploration (T 2), and at the time of suturing (T 3) were compared between the two groups; the intraoperative sufentanil and remifentanil consumption was recorded; the visual analogue score (VAS) of pain at 2, 8, 16, 24, and 48 h postoperatively and the number of analgesic pump presses and remedial analgesia at 48 h postoperatively were recorded. The incidence of adverse effects such as postoperative hypotonia (lower limb muscle strength ≤grade 4 on the blocked side), hypotension, nausea and vomiting were recorded. Results:The MAP and HR at T 1, T 2 and T 3, the dosage of sufentanil and remifentanil during operation of group L were lower than those of group T(all P<0.05); the VAS score at 2, 8, 16 and 24 hours after operation in group L were lower than those of group T (all P<0.05). The number of analgesic pump presses and remedial analgesia at 48 hours postoperatively in group L were less than those in group T after operation (all P<0.05). There was no statistically significant difference in the incidence of adverse reactions such as postoperative hypokinesia, hypotension, nausea and vomiting in the two groups (all P>0.05). Conclusions:LSQLB for open liver surgery is more hemodynamically stable and has a more definite analgesic effect.

Objective: To evaluate the safety and efficacy of foam sclerotherapy for bleeding internal hemorrhoids. Methods: Consecutive adult patients (aged 18-60 years) with bleeding hemorrhoids were prospectively enrolled between March 2017 and March 2018. All patients were randomly assigned to the foam sclerotherapy (FS) group and the liquid sclerotherapy (LS) group. The foam and liquid sclerotherapy of hemorrhoids nucleus was performed by cap-assisted colonic endoscopy. Results: A total of 108 patients were enrolled, including 62 males (57.4%) with mean age of 44.0±7.6 years. There was no significant difference in gender, age, or body mass index between the FS (n = 55) group and the LS (n =53) group. The total amount of lauromacrogol injection in the FS group was 3.7±0.9 mL, which was significantly lower than that in the LS group (8.0±2.2 mL, P<0.001). In the LS group, 8 patients (15.1%) developed bleeding after needle removal, which was significantly higher than that in the FS group [5.5%(3/53), P=0.022]. Significant pain was found in 2 patients (3.8%) in the LS group and 0 in the FS group (P= 0.025). The short-term cure rate and effective rate of the FS group were 87.3% (48/55) and 9.1% (5/55), while those were 69.8% (37/53) and 22.6% (12/53) in the LS group, respectively (P=0.046). Conclusion Foam sclerotherapy is safe and effective in the treatment of bleeding internal hemorrhoids.

Objective To study the effect of pioglitazone,a member of the thiazolidinedione (TZD) class with hypoglycemic action to treat diabetes,on expression of p38 mitogen-activated protein kinase in myocardium of rats following I/R injury.Methods Twenty-four healthy SD rats were randomly divided into sham group,I/R injury group,pioglitazone treatment group and pioglitazone+peroxisome proliferator-activated receptors-γ specific antagonist GW9662 treatment group (6 in each group).A rat I/R injury model was established by ligating the left anterior descending coronary artery.Apoptosis of myocardial cells was assayed by Terminal dUTP deoxynucleotidyl transferase nick end labeling.Expression of p-p38 protein was detected by Western blot.Results The apoptosis index of myocardial cells was significantly lower in sham operation group and piogl itazone treatment group than in I/R injury group and was significantly higher in pioglitazone+ GW9662 treatment group than in pioglitazone treatment group (8.6％±4.3％,21.4％±8.8％ vs 40.1％±12.3％,P＜0.05;37.0％-10.5％ vs 21.4％±8.8％,P＜0.05).The expression level of p-p38 was significantly lower in sham operation group and pioglitazone treatment group than in I/R injury group and was significantly higher in pioglitazone+GW9662 treatment group than in pioglitazone treatment group (P＜0.05).Conclusion Pioglitazone can inhibit I/R injury-induced apoptosis of myocardial cells by downregulating the expression of p-p38 protein.

Objective To evaluate the value of MR threedimensional arterial spin labeling (3D-ASL) perfusion imaging and intravoxel incoherent motion(IVIM) DWI in differential diagnosis and quantitative analysis of musculoskeletal tumors.Methods Forty-four patients with musculoskeletal tumors were included.According to pathologic results,there were 12 cases of benign tumors,10cases of intermediate tumors and 22 cases of malignant tumors.3D-ASL and IVIM DWI were both performed on forty-four patients to gain tumor blood flow (TBF),standard ADC (ADCstandard),slow ADC (ADCslow)and fast ADC (ADCfast).Immunohistochemical staining of specimens was performed by using CD34 monoclonal antibody to calculate microvessel density (MVD) counts.MVD,TBF,ADCfast and ADCslow of different groups were compared by one-way ANOVA analysis.ADCstandard was compared by Kruskal-Wallis test.ROC curve was used to analyze ASL and IVIM DWI,in order to determine the threshold and diagnostic reliability.Results The MVD of benign tumors was 10±4,the MVD of intermediate tumors was 15±6,and malignant tumors was 33 ± 1 1.There was significant difference among three groups of MVD(F=28.33,P＜0.05).There was better intra-observer agreement for ADCstandard,ADCfast,ADCslow and TBF(ICC=0.970,0.885,0.778,0.891,respectively,P＜0.05).The TBF of benign tumors was(30±10)ml· min-1· 100 g-1,intermediate tumors was(30± 12) ml·min 1· 100 g-1,and malignant tumors was(84±29)ml·min 1· 100 g-1.There was significant difference among three groups of TBF(F=32.34,P＜0.05).According to the ROC analysis,when the cut-offvalue of TBF was 45.5 ml·min-1· 100 g-1,the area under ROC curve was 0.95 1,and the sensitivity and specificity of TBF in diagnosing malignant tumors were 90.9％ and 95.5％ respectively.There was no significant difference among three groups of ADCstandard,ADCfastand ADCslow of benign tumors were(9.9±5.1)× 10-3,(1.9±0.5) × 10-3mm2/s respectively.ADCfast and ADCalow of intermediate tumors were(8.2 ± 3.6) × 10-3,(1.5 ± 0.6) × 10-3mm2/s respectively.ADCfast and ADCalow of malignant tumors were (16.9 ± 5.8) × 10 3,(1.4 ± 0.6) × 10-3mm2/s respectively.There were significant difference of ADCfast and ADCslow among three groups (F=12.75,5.60,P＜ 0.05).According to the ROC analysis,when the cut-off value of ADCfast was 9.4× 10-3mm2/s,the area under ROC curve was 0.861,the sensitivity and specificity of them in diagnosing malignant tumors were 95.5％ and 68.2％ respectively.Conclusion 3D-ASL and IVIM DWI are valuable in the differential diagnosis of musculoskeletal tumors.

In industrial application of NAD(P)H-dependent dehydrogenases, NAD(H) has the advantages over NADP(H) in higher stability, lower price and wider recycling system. Recently, a meso-2,6-diaminopimelate dehydrogenase from Symbiobacterium thermophilum (StDAPDH) has been found to be a useful biocatalyst for the production of D-amino acids, but it requires NADP(H) as co-enzyme. To switch the co-enzyme specificity from NADP(H) to NAD(H), we studied the effect of Y76 on the co-enzyme specificity of StDAPDH, because the crystal structural analysis indicated that residue Y76 is near the adenine ring. The mutation of Y76 exerted significant effect on the co-enzyme specificity. Furthermore, the double mutant R35S/R36V significantly lowered the specific activity toward NADP+, and the combination of R35S/R36V with some of the Y76 mutants resulted in mutant enzymes favorable NAD+ over NADP+. This study should provide useful guidance for the further development of highly active NAD(+)-dependent StDAPDH by enzyme engineering.
Amino Acid Oxidoreductases ; chemistry ; Amino Acids ; Clostridiales ; enzymology ; Mutation ; NAD ; NADP ; Substrate Specificity

Objective To explore the relationship between the tumor angiogenesis index (microvessel density,MVD)and biological behavior of the tumor.To analyze the correlations between TBF,standard ADC,fast ADC,slow ADC and MVD counts.Methods From March 2013 to June 2013,a total of 40 patients were involved in the study.3D-ASL and IVIM DWI were both performed on patients with musculoskeletal tumors.TBF,standard ADC,slow ADC,fast ADC were measured by regions of interest.Immunohistochemical staining of specimens were performed by using CD34 monoclonal antibody to calculate MVD counts.Group differences in MVD were assessed by using one-way ANOVA.The correlations between TBF,standard ADC,fast ADC,slow ADC and MVD counts were evaluated using Pearson correlative analysis.Results The MVD of benign tumors was (10.38±4.58)/0.26 mm2,the MVD of intermediate tumors was (14.64±6.69)/0.26 mm2,and the MVD of malignant tumors was (32.97±11.61)/0.26 mm2.The differences of MVD among three groups were statistically significant (F=28.83,P＜0.05).The differences of MVD between benign and malignant group were statistically significant (P＜0.05),as well as intermediate and malignant group (p=0.000).There was a significant positive correlation between TBF and MVD (r=0.784,P=0.000),as well as the correlation between TBF and fast ADC(r=0.727,P=0.000).There was a moderate positive correlation between fast ADC and MVD (r=0.516,P=0.000).There were no significant correlation between slow ADC and MVD,or between standard ADC and MVD.Conclusion The MVD represents the angiogenesis of musculoskeletal tumors,reflecting biological behavior of the tumor.ASL and IVIM DWI can be applied to evaluate the angiogenesis of musculoskeletal tumors by reflecting MVD of musculoskeletal tumors in vivo as a completely noninvasive technique.

Aortic Valve ; Fibroma ; Heart Neoplasms ; Humans

Objective To investigate the N-terminal-pro-B-type natriuretic peptide (NT-proBNP) concentration in the difference myocardial wall motion after essential hypertension. Methods 326 patients with essential hypertension and normal heart function and 265 control subjects were measured with their NT-proBNP. According to Canau's categories, the ventricle geometries of patients with high left ventricular mass index were divided into 2 groups. Results NT-proBNP was significantly higher in patients with hypertension than in controls. After grouped by different myocardial wall motion, the patients with concentric hypertrophy were highest among all the groups; the groups with eccentric hypertrophy was secondly highest; concentric remodeling and normal geometric pattern were not significantly higher than the controls. Conclusion NT-proBNP is different in patients with different myocardial wall motion before heart failure, which may play an important role in myocardial remodeling.

Objective To study the effects of adenosine triphosphate (ATP) on proliferation of human squamous esophageal carcinoma Eca-109 and hepatoma SMMC-7721 cells in vitro and the underlying mechanism. MethodsMTT assay was used to determine the proliferation of tumor cells. The AO/EB double stained cells were observed under fluorescence microscope. The effects of ATP on the cell cycle, apoptotic rate and apoptosis-related protein were detected by flow cytometry. Results ATP showed inhibitory effects on Eca-109 and SMMC-7721 cells at the concentration of 0.01～0.3 mmol/L. Exposure to 0.3 mmol/L ATP for 72 h, some of SMMC-7721 cells displayed morphological changes of apoptosis, but Eca-109 cells did not show the characteristics of apoptosis markedly. There was no significant change in the apoptotic rate and apoptosis-related protein of the two tumor cell lines treated with ATP 0.03, 0.1 and 0.3 mmol/L for 72 h respectively. The proportion of Eca-109 cells in G0/G1-phase of cellcycle was significantly increased, meanwhile the proportion of Eca-109 cells in S-phase and proliferation index value was significantly decreased by treatment with 0.3 mmol/L ATP. Conclusion ATP inhibited Eca-109 cell proliferation by changing the distribution of cell cycle phase, and its mechanism might not related to apoptosis, but for SMMC-7721 cell, the inhibition of cell proliferation induced by ATP was not related to the change in cell cycle.