Objective:To establish a method for obtaining planning target volume (PTV) and planning risk volume (PRV) margins caused by rotation in the use of adapt-to-position (ATP) modality of magnetic resonance linear accelerator (MRL) for patients with intracranial tumors.Methods:Clinical data of 6 patients with intracranial tumors (150 fractions in total) who received MRI-guided online ATP radiotherapy in Peking Union Medical College Hospital from November 2023 to January 2024 were retrospectively analyzed. The pre-planned CT structure was copied onto each segmented MR image and then the structures were traced back to the CT image according to the three-dimensional registration relationship. The anisotropic distance of the structure based on the original CT structure was calculated to obtain the variation range of the target and the organs at risk. The maximum anisotropic value was taken as the result of the PTV and the relationship between the results and intracranial location of different patients was analyzed. Group comparison was performed by Chi-square test. Two group comparison was conducted by post-hoc Wilcoxon signed-rank test. Results:After the rotation deviation was included, the range of target changes in the six directions of left and right (L/R), anterior and posterior (A/P) and superior and inferior (S/I) of the 6 patients were: (1.24± 0.86) mm/(1.91± 1.07) mm, (2.02± 1.26) mm/(1.66± 1.07) mm, (1.84± 1.84) mm /(2.94±1.93) mm, respectively. The results in the SI direction were significantly different, and the values in the I direction in 2 patients exceeded 4 mm, the margins suitable for all patients were 3.01 mm/2.4 mm(A/P), 1.9 mm/2.93 mm(L/R) and 3.14 mm/4.62 mm(S/I) in different directions, respectively. The L/R direction of the lens and the S/I direction of the optic nerve were significantly changed, and the A/P direction of the brain stem was (3.99± 4.64) mm. Larger values might be required when the target was in the posterior brain (left-down area, right-down area).Conclusions:The rotation deviation, organ movement and intracranial location affect the PTV and the organs at risk PRV in the MRI-guided ATP modality in intracranial tumors patients. The margin generation method based on image fusion can help to quantify the margin value reasonably.

Letrozole,a third generation non-steroidal aromatase inhibitor,has been approved for the treatment of breast cancer in women.In recent years,it has been used in the field of growth and development in children,such as childhood dwarfism,somatic delayed pubertal growth and precocious puberty,but the long-term effects on liver and kidney function,lipid metabolism,reproductive function and bone metabolism are unclear.Studies have shown that letrozole can cause abnormal testicular morphology,changes in seminiferous tubules and interstitial tissues,reduce bone density,affect the bal-ance of bone metabolism,and cause cognitive impairment and apoptosis of nerve cells.The mecha-nism of reproductive toxicity of letrozole may be related to its influence on the development and matura-tion of testicular cells,the expression of sex hormones and gonadotropins in vivo,and the distribution and expression of estrogen receptors in testicular tissues.The mechanism of bone metabolic toxicity is related to its increase in the proliferation and differentiation of osteoclasts induced by receptor activator of NF-κB ligand,as well as the increase of apoptosis,oxidative stress and NF-κB activity of osteo-blasts.The mechanism of cognitive toxicity is related to its regulation of classical and nonclassical effects of the hippocampus,reduction of glutamate uptake by astrocytes,and reduction of L-type calcium channel blockade of caspase 3 activation.This article is to provide reference for safe and effective use of letrozole in clinical pediatrics.

Objective To explore the clinical efficacy of marginal liver from elderly donors in liver transplantation. Methods According to the inclusion and exclusion criteria, the clinical data of 127 donors and recipients were retrospectively analyzed. According to the age of donors, 127 donors were divided into the elderly group (n=27) and control group (n=100). The recovery of liver function, the occurrence of postoperative complications and survival rate of the recipients after transplantation were statistically analyzed between two groups. Results The incidence of primary nonfunction (PNF) and initial poor graft function (IPGF) did not significantly differ between the elderly and control groups (both P > 0.05). Within postoperative 2 weeks, the average levels of alanine aminotransferase (ALT) and serum total bilirubin (TB) of liver transplant recipients in the elderly group was not significantly different from those in the control group (both P > 0.05). There was no significant difference in the incidence of postoperative complications in the postoperative elderly group compared with the control group (all P > 0.05). The 1-and 3-year survival rates of the recipients in the elderly group were 84% and 78% respectively, which did not significantly differ from 89% and 79% in the control group (both P > 0.05). Conclusions Strict and sufficient quality evaluation and functional maintenance should be done for elderly donor livers. It can achieve good transplantation results by intraoperative fine operation, reducing bleeding and trauma, shortening the time of cold ischemia and operation, strengthening postoperative monitoring and implementing enhanced recovery after surgery.

Objective:To investigate the risk of occupational hearing loss caused by noise exposure in an automobile parts manufacturing enterprise.Methods:In June 2019, an automobile parts manufacturing enterprise in Huizhou City was selected to conduct occupational hygiene field investigation, and occupational health investigation and occupational hazards detection were carried out in the workplace. 395 workers with 8-hour working day equivalent sound level (L ex·8 h) ≥85 dB (a) were selected as the research objects. The occupational noise exposure risk assessment method was used to assess the noise exposure risk of L ex·8 h≥85 dB (a) , and the risk of high-frequency hearing loss and occupational noise deafness caused by noise exposure were evaluated when the working years were 10, 20, 30, 35 and 40. Results:When the exposure years were less than or equal to 30 years, the risk of high-frequency hearing loss of bearing pedestal final examiners was medium risk, and the risk of other positions was acceptable; the highest risk of noise deafness was the bearing pedestal final examiner, and the risk classification was higher, and the other types of work were negligible risk and acceptable risk. When the exposure years are more than 30 years, the risk classification of high-frequency hearing loss of bearing pedestal final inspection workers is high-risk, and the risk classification of other types of work is medium risk; the highest risk of noise deafness is the bearing pedestal final inspection workers, and the risk classification is higher risk, and the other types of work are medium risk.Conclusion:The enterprise should pay attention to the risk of occupational hearing loss caused by noise exposure, especially the bearing pedestal final inspection workers, and strengthen the hearing protection of noise exposed people.

Objective:To investigate the risk of occupational hearing loss caused by noise exposure in an automobile parts manufacturing enterprise.Methods:In June 2019, an automobile parts manufacturing enterprise in Huizhou City was selected to conduct occupational hygiene field investigation, and occupational health investigation and occupational hazards detection were carried out in the workplace. 395 workers with 8-hour working day equivalent sound level (L ex·8 h) ≥85 dB (a) were selected as the research objects. The occupational noise exposure risk assessment method was used to assess the noise exposure risk of L ex·8 h≥85 dB (a) , and the risk of high-frequency hearing loss and occupational noise deafness caused by noise exposure were evaluated when the working years were 10, 20, 30, 35 and 40. Results:When the exposure years were less than or equal to 30 years, the risk of high-frequency hearing loss of bearing pedestal final examiners was medium risk, and the risk of other positions was acceptable; the highest risk of noise deafness was the bearing pedestal final examiner, and the risk classification was higher, and the other types of work were negligible risk and acceptable risk. When the exposure years are more than 30 years, the risk classification of high-frequency hearing loss of bearing pedestal final inspection workers is high-risk, and the risk classification of other types of work is medium risk; the highest risk of noise deafness is the bearing pedestal final inspection workers, and the risk classification is higher risk, and the other types of work are medium risk.Conclusion:The enterprise should pay attention to the risk of occupational hearing loss caused by noise exposure, especially the bearing pedestal final inspection workers, and strengthen the hearing protection of noise exposed people.

Objective To evaluate the feasibility,effectiveness and safety of Carto3 three-dimensional electrophysiological mapping system in guiding radiofrequency ablation (RFA) for paroxysmal supraventricular tachycardia (PSVT).Methods The clinical data of a total of 28 patients with PSVT (Carto group),who received RFA guided by Carto3 three-dimensional electrophysiological mapping system during the period from March 2015 to February 2016,were retrospectively collected.Other 36 parents with PSVT,who received fluoroscopy-guided RFA during the period from March 2014 to February 2015,were collected as control group.The X-ray irradiation time,success rate of operation,operation time,complication and recurrence rate were calculated and the results were compared between the two groups.Results The mean fluoroscopy time in Carto group was (2.6±2.3) min,which was significantly less than (15.8±9.5) min in the control group (P＜0.001),and among them zero X-ray irradiation was obtained in 8 patients who had atrioventricular nodal reentrant tachycardia (AVNRT).The operation success rates of Carto group and the control group were 100％ (28/28) and 94.4％ (35/36) respectively (P＞0.05).The operation time in Carto group and the control group was (162.7±34.4) min and (149.4±46.2) min respectively (P＞0.05).In Carto group no any complications occurred,and in the control group one patient with AVNRT developed transient degree Ⅱ atrioventricular block during ablation process.All patients were followed up for 6 months,and no recurrence was observed in all patients of both groups.Conclusion For the treatment of PSVT,RFA guided by Carto3 three-dimensional electrophysiological mapping system is safe and effective,it can significantly reduce the X-ray irradiation time,even zero X-ray radiation in some AVNRT patients,meanwhile,this technique does not increase operation time and operation risk.

Objective: To optimize the construction of combined hypoxia NASH rat model on the basis of preliminary work, and to explore the role of neovascularization in the process of hepatic fibrosis. Methods: 32 rats were divided randomly to four groups that were null control group(A group ), hypoxia group(B group), high fat diet group(C group ) and high fat diet plus hypoxia group (D group ),treated with null , Intraperitoneal injection of NaNO₂, high fat diet and high fat diet plus Intraperitoneal injection of NaNO₂ respectively. Every group was observed for 16 weeks, B and D group was treated with Intraperitoneal injection of NaNO₂ 20 mg/kg.d at the laster 8 weeks. Liver histology NASH activity score(NAS) and Fibro score(FibroS), biochemical index were detected in this combined hypoxia NASH rat model(D group), meanwhile the changes of HIF1α, inflammatory factor and neovascularization were measured by ELISA, realtime PCR and immunohistochemistry. Results: Liver tissue NAS > 4 was seen in C and D group. D group showed NASH characteristics, including significantly steatosis at liver acinar 3 area(mostly a microvesicular type fat droplets mixed with macrovesicular type), hepatocyte balloon degeneration, obvious lobular inflammation, while fibrosis score increased significantly, including visible hepatic sinusoid fibrosis, fibrosis around portal vein, and bridging fibrosis in a considerable portion of the rats. Compared with C group, biochemical indicators of aspartate aminotransferase (AST), HIF1α, neovascularization-related VEGFA, VEGFR2 mRNA level increased obviously and the expression of immunohistochemistry VEGFR2, CD34 enhanced markedly in D group(p < 0.05). Conclusion A combined hypoxia NASH rat model can be established throught feeding 16 weeks’ high-fat diet then intraperitoneal injection of NaNO₂ 20 mg / kg.d at the laster 8 weeks, meanwhile chronic hypoxia can accelerate this combined hypoxia NASH model liver fibrosis process. In this process neovascularization promoted the formation of hepatic fibrosis in this model.

Organ system based integrated teaching model has been adopted in several medical schools, and these schools face some challenges in this teaching process. In order to provide new sights for organ system based integrated teaching reform in eight-year medical education program, ex-ploration of setting up three-staged-dimensional integrated teaching models was conducted in urinary system by hematuria, and designing related teaching objectives, teaching programs and assessment form to optimize teaching quality in this teaching methods, according to characteristics of the urinary systemic diseases, cultivating objectives of eight-year medical education program and teaching experi-ence of Xiangya School of Medicine.

Objective To analyze the imaging features of mycobacterium in AIDSpatients.Methods Twenty-three cases of mycobacterium tuberculosis and 13 patients of non-tuberculous mycobacteria were proved etiologically and included in this study.All patients underwent X-ray and CT examinations,imaging data were analyzed and compared.Results The imaging findings of mycobacterium tuberculosis in AIDS patients included consolidation (n =11),pleural effusion (n =11),mediastinal lymphadenopathy (n =11).Pulmonary lesions were always diffuse distribution,and 14 patients of extrapulmonary tuberculosis were found.Pulmonary lesions in non-tuberculous mycobacteria tend to be circumscribed.Conclusions Non-tuberculous mycobacterial infection in AIDS patients is more common and usually combined with other infections.Imaging features are atypical.

Objective To determine the changes of peripheral levels of T helper cell cytokines of patients with chronic hepatitis B (CHB) during antiviral treatment,and to further explore its clinical significance.Methods The plasma levels of interleukin (IL)-2,IL-6,IL-10,interferon (IFN)-γ and tumor necrosis factor(TNF)-α of thirty-three CHB patients during antiviral treatment (entecavir) were measured using enzyme linked immunosorbont assay (ELISA).And their biochemical indicators of liver function were determined.The differences of cytokines levels before and after antiviral treatment were compared using ANOVA.The correlations between the changes of cytokines and alanine transaminase (ALT),hepatitis B virus (HBV) DNA levels were analyzed.Results Levels of IFNγ before and 12,24,48 weeks after treatment were (5.98±2.77),(5.95±3.37),(2.93±2.15) and (9.29±4.65) pg/mL,respectively (F=3.845,P＜0.05),which were positively correlated with ALT levels (r =0.396,P＜0.05).Both TNF-α and IL-10 levels declined after antiviral treatment,which were significantly different at different time points (F=20.156 and 16.695,respectively; both P＜0.05),and both levels of TNF-α and IL-10 were positively correlated with ALT levels (r=0.354and 0.316,respectively; both P＜0.05) and positively correlated with HBV DNA levels (r=0.382and 0.386,respectively; both P＜0.05).While both IL-2 and IL-6 levels were not significantly different between before and after antiviral treatment (F=0.010 and 0.932,respectively; both P＞0.05).The serum levels of ALT and HBV DNA before and after antiviral treatment were all significantly different (F=17.69 and 198.98,respectively; both P＜0.05),which declined gradually during treatment and were positively correlated (r =0.581,P＜0.05).Conclusions IL-10,IFNγand TNF-α may be involved in the pathologic process of CHB,and closely related to the deterioration of the disease.Monitoring plasma levels of these cytokines during antiviral treatment could be useful to understand the immune status and evaluate the efficacy of antiviral drugs.