Objective To investigate the frequency and dose of X-ray computed tomography (CT) medical exposure in Shantou City, and to evaluate the collective effective dose burden of residents caused by CT medical exposure. Methods The study subjects were selected using the stratified random sampling method from CT scanners in all medical institutions in Shantou City in 2020. CT application units were divided into the four tiers of municipal hospitals, district hospitals, subdistrict hospitals, and private hospitals, and 50% of the hospitals in each tier were randomly selected according to the number of hospitals in the tier. The study analyzed CT dose index results, CT scanning standard conditions, and the distribution of characteristic doses of medical exposure to evaluate the dose burden of residents in Shantou City caused by CT medical exposure. Results There were 51 CT scanners in medical institutions in Shantou City. By the end of 2020, the average number of CT scanners per million population was 9.30, and the frequency of CT medical exposure was 135.24 per 1000 population. Jinping District had the highest number of CT scanners per million population (23.2), while Chaoyang District had the lowest number of CT scanners per million population (3.6). The median and range of effective doses for different scan regions were 1.65 (0.76, 4.49) mSv in the head, 4.12 (1.90, 53.21) mSv in the chest, 5.96 (2.68, 10.25) mSv in the abdomen, and 10.30 (4.12, 12.67) mSv in the lumbar spine. By the end of 2020, the effective dose to the public in Shantou City was 6080.67 Sv·person, and the average annual effective dose per person was 1.10 mSv. Conclusion Medical exposure is the most important factor affecting resident dose burden, particularly the overuse of medical exposure examinations. CT examination is the most significant component of medical exposure causing resident dose burden. Reducing unnecessary medical exposure, ensuring the rational use of CT examination, and properly utilizing personal protective equipment are effective measures to minimize the dose burden on examinees.

BACKGROUND:The anterior cruciate ligament has unique nonlinear mechanical properties under a complex physiological loading environment.Elastin is an important contributor to the mechanical properties of the anterior cruciate ligament,but its mechanical response to the anterior cruciate ligament under axial tension is not clear. OBJECTIVE:To quantitatively analyze the effect of elastin on the tensile mechanical response of the anterior cruciate ligament. METHODS:Elastase solution and control buffer were prepared.The porcine anterior cruciate ligament samples were prepared into small-size samples and randomly soaked in 0,0.1,1.0,2.0,5.0,and 10.0 U/mL elastase solution for 6 hours,and other small samples of the same size were soaked in 2 U/mL elastase solution for 0,1,3,6,9,and 12 hours.To determine suitable soaking conditions for elastin-targeted enzymes and verify the digestive effect,histological staining was used to compare the effects of enzyme treatment on tissue structure and composition.The ligament samples were randomly divided into elastase-treated group and PBS group,and immersed in 2 U/mL elastase solution and PBS buffer for 6 hours,respectively.A mechanical tensile test was performed before and after immersion. RESULTS AND CONCLUSION:(1)The biochemical results showed that being treated in 2 U/mL elastase solution for 6 hours could reduce the elastin content by 31.1%,and had no significant effect on other mechanical-related components in the tissue.(2)The histological results showed that elastase was able to penetrate the tissue,and the loose degree of tissue increased after treatment.(3)In the mechanical results before and after treatment,the mechanical properties of the PBS group decreased significantly,only the low-tension elastic modulus increased significantly and the initial length increased significantly in the elastase-treated group.(4)The intergroup comparison results showed that there was no significant difference between the two groups in pre-treatment,but the low-tension elastic modulus,initial slopes,saturated slopes,and initial length of the elastase-treated group after treatment were significantly higher than those in the PBS group.(5)These results suggest that elastin degradation significantly affects the biomechanical properties of the anterior cruciate ligament and further complements our understanding of the structure-function relationship of the anterior cruciate ligament.

Humans ; Neoplasms, Second Primary/epidemiology* ; Neoplasms/epidemiology* ; Risk Factors ; Prognosis

Objective:To evaluate the diagnostic value of exercise stress echocardiography combined with left ventricular two-dimensional speckle tracking layer-specific strain technique in evaluating subclinical myocardial damage and reserve function in patients with hypertension.Methods:A total of 51 healthy subjects(control group) and 55 hypertensive patients (hypertension group) were enrolled in the treadmill exercise stress test in Sichuan Provincial People′s Hospital from October 2018 to January 2020. According to the European Guidelines for the Prevention and Treatment of Hypertension, the inclusion criteria for patients with hypertension were: blood pressure≥140/90 mmHg or who explicitly took antihypertensive drugs, and related cardiovascular diseases were excluded. The conventional parameters of resting and peak exercise, including left ventricular mass index, left ventricular end-diastolic volume index and left ventricular ejection fraction et al, were analyzed by speckle tracking software in two groups. According to the standard images in the resting and peak exercise, the endocardium /mid-myocardium /epicardium of left ventricular (three-, two-, four-chamber and global) longitudinal strain and circumferential strain (papillary muscle level) were compared respectively in two groups. The characteristics of strain differences and the systolic function reserve between the resting and peak exercise were evaluated.Results:There were significant differences in conventional ultrasound parameters between resting and peak exercise period in hypertension group, except E/A and e/a ratio (all P<0.05), and E/e value increased significantly(12.1±0.38) during peak exercise, indicating impaired diastolic reserve function. The longitudinal and circumferential layer-specific strain values from endocardial to epicardial were gradually decreased in both two groups. Compared with the control group, the resting longitudinal and circumferential endocardial strain values in hypertensive group were decreased, and the differences were more obvious at peak status, for instance global longitudinal endocardium strain at rest[control group (24.4±1.5)%, hypertension group (20.4±2.3)%], peak status[control group (30.8±2.8)%, hypertension group (22.8±2.9)%]( P<0.05). There were no significant differences of the partial layer-specific strain values between the peak exercise and resting status in hypertension group, while peak layer-specific strain of the control group were all significantly increased, suggesting that the left ventricular systolic reserve function of hypertension patients was lower than that of the control group. Conclusions:Left ventricular layer-specific strain can effectively evaluate the myocardial function in patients with hypertension, especially the endocardial strain can be used as an indicator parameter, and the peak exercise stress state is more sensitive. The systolic and diastolic reserve function of the left ventricle in patients with hypertension at the peak period are reduced to different degrees. Exercise stress echocardiography combined with left ventricular layer-specific strain technique can be used as a new method for detection of myocardial function impairment in patients with hypertension.

OBJECTIVE: To explore the inhibitory effects of silencing long non-coding RNA (LncRNA) HIF1A-AS2 on epithelialmesenchymal transition (EMT) and tumor stem cell-like phenotype in cervical cancer cells. METHODS: We designed 3 shRNA constructs for silencing HIF1A-AS2 in CaSki cells, and the shRNA with the strongest interference effect was selected for subsequent experiment. CaSki cells were transfected with shRNA-NC or Sh-HIF1A-AS2, and the changes in cell viability, invasion ability, EMT, expressions of EMT-related proteins, formation of cell spheres and expressions of stem cell markers were detected. RESULTS: Transfection with shRNA-NC and Sh-HIF1A-AS2 did not significantly affected the viability of CaSki cells ( CONCLUSIONS Silencing HIF1A-AS2 can inhibit proliferation, invasion and migration of cervical cancer cells
Cell Line, Tumor ; Cell Movement/genetics* ; Cell Proliferation/genetics* ; Epithelial-Mesenchymal Transition/genetics* ; Female ; Gene Expression Regulation, Neoplastic ; Humans ; Hypoxia-Inducible Factor 1, alpha Subunit ; RNA, Long Noncoding/genetics* ; RNA, Small Interfering/genetics* ; Uterine Cervical Neoplasms/genetics*

Objective To evaluate left ventricular ( LV ) myocardial mechanical transmural longitudinal displacement ( LD ) and radial displacement ( RD ) with contrast agent and different power irradiation in open‐chest Beagle canines by ultrasound velocity vector images ( VVI) workstation . Methods T he anesthetized open‐chest Beagle canines were assigned into two groups randomly :Group A ( n ＝6) for baseline ,diagnostic ultrasound power irradiation ( 300 mW) 5 min ,combined with contrast agent irradiation 5 min and contrast agent 20 min conditions ; Group B ( n ＝ 6 ) for baseline and intensity ultrasound irradiation ( 1 W ,2 W and 3 W ,5 min respectively) conditions . T he standard short‐axis and long‐axis gray‐scale view s during three complete cardiac cycles in open‐chest Beagle canine models were acquired . T he peak LD subendomyocardium ( LD‐subendo) ,LD subepimyocardium ( LD‐subepi) ,RD subendomyocardium ( RD‐subendo) and RD subepimyocardium ( RD‐subepi ) of LV were analyzed using a dedicated Syngo VVI method . Results In group A ,the LV LD‐subendo ,LD‐subepi ,RD‐subendo and RD‐subepi in the most of segments showed increasing trend in diagnostic power irradiation ,contrast agent irradiation 5 min and contrast agent 20 min compared with baseline condition ,however the differences were not significant ( P ＞0 .05 ,respectively) . T he peak LD‐subendo and LD‐subepi ,RD‐subendo and RD‐subepi of LV in group A with the same condition were significant different ( all P ＜0 .05) . In group B ,LV LD‐subendo in ultrasonic power 3 W was lower than baseline condition ( P ＜ 0 .05 ) ,LV RD‐subendo was higher compared with baseline condition ( P ＜0 .05) . T he peak LD‐subendo and LD‐subepi ,RD‐subendo and RD‐subepi of LV in group B with the same condition were significant different ( all P ＜ 0 .05) . Conclusions On ultrasonic power 3 W ,LV LD‐subendo is decreased resulting to negative inotropic effect and RD‐subendo is increased to maintain the normal heart work .LV LD and RD on diagnostic ultrasound power irradiation 5 min , combined with contrast agent irradiation 5 min ,contrast agent 20 min conditions ,ultrasonic power 1 W and 2 W are not prominent changes .

Objective To investigate the clinical characteristics,diagnosis and treatment of congenital tracheobiliary fistula (CTBF) in children.Methods A case of CTBF admitted into the Department of Pediatric Respiration,Hubei Maternal and Child Health Care Hospital in 2016 was reported,and the related literatures were reviewed.The clinical features,diagnostic methods,treatment status and clinical outcomes of the disease were analyzed.Results The patient was 3 years and 7 months old.The main clinical manifestations were recurrent cough,pneumonia and atelectasis.CTBF was diagnosed by means of iodine oil radiography and treated with biological glue plugging under bronchoscopic guidance.So far,only 30 cases of CTBF have been reported in the English literatures,but only 2 cases in the Chinese literatures.The main clinical manifestations were cough,dyspnea,sputum or bile vomiting,aspiration pneumonia,atelectasis or emphysema.Diagnostic methods for CTBF included bronchoscopy,bronchial angiography and cholangiography,hepatobiliary scan,CT scan and magnetic resonance imaging.Except for this case treated with biological glue plugging under bronchoscopic guidance,all other patients were treated with surgery.The operation methods included fistula ligation,gastrostomy,liver resection,fistula jejunum Roux-en-Y anastomosis,hepatic hilum jejunum anastomosis,gallbladder jejunum anastomosis,etc.Only 4 cases died,and the rest of the patients recovered.Conclusions CTBF should be suspected in children with persistent chronic cough.Iodine oil radiography through bronchoscopy is a simple and feasible method for diagnosis of CTBF.Besides surgery,the lavage and the biological glue plugging method through bronchoscopy is also an effective way to treat CTBF in children without severe biliary malformation.

Objective To investigate whether a 3D printed model of the contrlateral healthy distal radius, especially its articular accuracy, helps anatomical reduction and precise reconstruction of the fractured distal radius. Methods The CT data of bilateral radii were collected from 15 normal volunteers ( 11 males and 4 females with an average age of 22. 8 years ) between November and December 2016. After 3D reconstruction of the bilateral distal 1/3 radii, solid 3D models of left radius were mirrored and generated by 3D printing. The data of right radii ( reference group ) were compared with the data of the solid 3D models of left radius acquired through a 3D scanner ( test group ) using deviation analysis. Results The maximum volume difference between the 3D printed model and the contralateral radius was 6. 86％. The average volume of the reference group was 19, 165. 82 ± 3, 250. 50 mm3 and that of the test group 19, 310. 65 ± 3, 305. 15 mm3, showing no statistically significant difference between the 2 groups ( t= -0. 941, P=0. 363 ) . The maximum surface area difference was 3. 84％ between the 2 groups. The average surface area of the reference group was 5, 075. 80 ± 549. 34 mm2 and that of the test group 5, 139. 43 ± 572. 48 mm2, showing a signifi-cant difference ( t= -2. 451, P=0. 028 ) . The 3D deviation analysis showed a mean positive deviation of 0. 37 ± 0. 10 mm and a mean negative deviation of 0. 30 ± 0. 07 mm. The maximum mean square root was 0. 65. The 3D deviation was distributed mainly within 1 mm interval, with a distribution frequency of 96. 27％. Conclusions A 3D printed model prepared by high precision equipment is accurate enough to guide reconstruction of distal radius fractures in adults. In the treatment of complex fractures of the distal radius, a 3D printed model of the contralateral healthy distal radius can be used as a reference to achieve anatomical reduction and precise reconstruction of the fractured distal radius.

Objective To evaluate left ventricular ( LV ) myocardial mechanical synchrony with contrast agent and different power irradiation in open-chest Beagle canines . Methods The anesthetized open-chest Beagle canines were assigned into two groups randomly : Group A ( n = 6 ) for baseline , diagnostic ultrasound power irradiation ( 300 mW ) 5 min ,combined with contrast agent irradiation 5 min and contrast agent 20 min conditions ;Group B ( n = 6) for baseline and intensity ultrasound irradiation ( 1 W ,2 W and 3 W ,5 min respectively) conditions . The standard short-axis gray-scale views at levels of mitral annulus ( MV) ,papillary muscle( PM ) ,and apex( AP) during 3 complete cardiac cycles in open-chest Beagle canine models were acquired . The global radial displacement peak time ( RD-PT) and standard deviation of peak time ( RD-PT SD ) of LV subendomyocardium ( subendo ) and subepimyocardium ( subepi ) were measured and analyzed by using a dedicated Syngo velocity vector imaging ( VVI) method . Results In group A ,compared with baseline condition , the RD-PT and RD-PT SD of subendo and subepi had no significant different among diagnostic power irradiation ,contrast agent irradiation 5 min and contrast agent 20 min ( all P < 0 .05) . There was no significant different in the RD-PT and RD-PT SD between subendo and subepi in A group in all conditions ( all P < 0 .05) . In group B ,the RD-PT and RD-PT SD of subendo and subepi with power 1 W ,2 W and 3 W was higher than those with baseline condition ;the RD-PT and RD-PT SD of subendo were significant different on 2 W compared with those on baseline condition ( all P <0 .05) ;the RD-PT and RD-PT SD of subendo ,subepi were significant different on 3 W compared with baseline condition ( all P < 0 .05) ;the RD-PT and RD-PT SD were significant difference between subendo and subepi in only 3 W condition ( all P < 0 .05 ) . Conclusions Diagnostic ultrasound power irradiation 5 min and combined with contrast agent irradiation 5 min and contrast agent 20 min conditions do not effect the synchrony of LV myocardial mechanics . Power more than 1 W can induce the delay of RD-PT and RD-PT SD of LV subendo and subepi . Power 3 W can result in dyssynchrony of LV myocardial mechanics .

Objective To evaluate left ventricular ( LV ) myocardial mechanical rotation and twist with contrast agent and different power irradiation in open-chest beagle canines by ultrasound velocity vector images ( VVI ) . Methods The anesthetized open-chest Beagle canines were assigned into two groups randomly :group A ( n = 6 ) for baseline ,diagnostic ultrasound power irradiation ( 300 mW ) 5 min , combined with contrast agent irradiation 5 min and contrast agent 20 min conditions ;group B ( n = 6) for baseline and intensity ultrasound irradiation ( 1 W ,2 W and 3 W ,5 min respectively ) conditions . The standard short-axis gray-scale views at basal level (BL) ,and apical level( AL) during three complete cardiac cycles in open-chest beagle canine models were acquired . The peak subendomyocardium rotation ( subendo-rot) ,subepimyocardium rotation ( subepi-rot) of BL and AL were analyzed using a dedicated Syngo velocity vector imaging ( VVI) method and LV subendomyocardium twist ( subendo-twi) and subepimyocardium twist ( subepi-twi) were defined as apical subendo-rot/subepi-rot - basal subendo-rot/subepi-rot . Results In group A ,the LV subendo-twi ,subepi-twi ,subendo-rot and subepi-rot of BL and AL in the most of segments were significant different on diagnostic power irradiation ,contrast agent irradiation 5 min and contrast agent 20 min ( P < 0 .05 ) compared with baseline condition ;LV subendo-twi was higher than subepi-twi in group A under the same condition ( P < 0 .05) . In group B ,LV subendo-twi ,subepi-twi and subendo-rot ,subepi-rot of BL and AL on power 1 W ,2 W were higher and subendo-twi ,subepi-twi on power 3 W were lower than those on baseline condition ( P < 0 .05) ;There was no difference in subendo-rot and subepi-rot of LV BL compared with baseline condition ( P > 0 .05) ;subendo-rot and subepi-rot of LV AL were different compared with those on baseline condition ( P < 0 .05) ;LV subendo-twi and subepi-twi in group B under the same condition were significant difference ( P < 0 .05) . Conclusions LV rotation and twist increase on diagnostic ultrasound power irradiation 5 min ,combined with contrast agent irradiation 5 min ,contrast agent 20 min conditions ,1 W and 2 W ;LV twist and AL rotation decrease on ultrasound power 3 W ,but BL rotation is not affected on ultrasound power 3 W .