BACKGROUND:Anterior cruciate ligament injury tends to lead to secondary meniscus injury and osteoarthritis.At present,there are few studies on the mechanics of meniscus and articular cartilage injury caused by anterior cruciate ligament injury. OBJECTIVE:To study the effect of partial rupture of the anterior cruciate ligament on the stress of medial and lateral meniscus and articular cartilage of knee joint by finite element analysis. METHODS:The CT and MRI images of the knee joint of a healthy volunteer were selected,and the scan data were imported into Mimics,Geomagic and SolidWorks software.After registration and fusion,four kinds of three-dimensional knee joint models were established:models of intact anterior cruciate ligament,rupture of the posterior external tract of anterior cruciate ligament,rupture of the anterior internal tract of anterior cruciate ligament,and absence of anterior cruciate ligament.Finally,data were imported into Ansys software to apply four different modes of loads to the knee joint:Longitudinal loads of 750 N were applied to the top of the femur;longitudinal load of 750 N to the top of the femur and forward thrust of 134 N behind tibia;a longitudinal load of 750 N and a varus moment of 10 Nm were applied to the top of the femur to simulate genu varus;750 N longitudinal load and 4 Nm internal rotation moment were applied to the proximal end of the femur to simulate knee internal rotation.The finite element analysis of biomechanical stress changes of the meniscus and articular cartilage of the knee joint was carried out. RESULTS AND CONCLUSION:(1)In the straight position of the knee joint,when the anterior medial tract of the anterior cruciate ligament was broken and the anterior cruciate ligament was missing under longitudinal loads of 750 N at the top of the femur,the total stress and peak value of meniscus increased significantly,but the stress distribution of the meniscus and the stress of articular cartilage did not change significantly.In longitudinal load of 750 N to the top of the femur and forward thrust of 134 N behind tibia,the fracture of the anterior internal tract of the anterior cruciate ligament increased the tibia forward,the compressive stress of posterior angle of the meniscus increased,and the stress of the articular cartilage did not change significantly.During simulating genu varus,the posterior angular stress of the lateral meniscus decreased,the stress of the medial meniscus increased,and the stress of articular cartilage slightly decreased when anterior cruciate ligament injuries were complete.When the anterior internal tract of the anterior cruciate ligament was broken or absent under knee internal rotation,the equivalent stress peak value of femoral cartilage and tibia cartilage shifted from medial cartilage to lateral cartilage,and the stress peak value of meniscus increased significantly.At this time,the anterior internal tract of the anterior cruciate ligament played a leading role in the rotational stability of the knee joint.(2)These results indicate that the risk of secondary meniscus injury in patients with anterior and medial anterior cruciate ligament band rupture was much higher than that in patients with posterior and external anterior cruciate ligament band rupture when the knee was in the upright standing position,varus and pronation,and there was no significant difference in the impact on articular cartilage.

BACKGROUND:The incidence of medial collateral ligament injuries in the knee joint is easy to lead to secondary meniscus and cartilage damage,and long-term chronic damage can lead to the occurrence of osteoarthritis.At present,there are few studies on the mechanics of meniscus and articular cartilage injury caused by medial collateral ligament rupture. OBJECTIVE:To investigate the effect of different degrees of medial collateral ligament injury on the biomechanics of meniscus and cartilage of knee joint. METHODS:The CT and MRI examinations of the knee joint of a healthy volunteer were performed to obtain the image data.The scanning data were imported into Mimics,Geomagic,and Solidworks software in turn.After registration and fusion,a 3D model of normal knee joint was established.On this basis,models of medial collateral ligament injury in different degrees of knee joint were simulated,which were divided into four groups,including:(1)medial collateral ligament was intact;(2)deep medial collateral ligament fracture;(3)superficial medial collateral ligament fracture;(4)complete rupture of medial collateral ligament.Finally,Ansys software was introduced to apply three modes of loads to the knee joint:(1)10 N·m valvaration torque was applied to the top of the femur.(2)A 4 N·m internal torque was applied to the top of the femur.(3)A 4 N·m external torque was applied to the top of the femur.The effects of four groups of models on knee biomechanics under different loads were analyzed. RESULTS AND CONCLUSION:(1)In the extension position of the knee joint,when a 10 N·m valgus torque was applied to the knee joint,the overall stress of the posterolateral meniscus increased with different degrees of medial collateral ligament injuries,while the stress of the articular cartilage did not change significantly.The peak stress of the posterolateral meniscus increased significantly with superficial medial collateral ligament rupture.(2)In the knee extension position,when a 4 N·m internal rotation torque was applied to the knee joint,the overall stress of the medial and lateral meniscus increased after different degrees of medial collateral ligament injury.When superficial medial collateral ligament rupture occurred,the peak stress of the meniscus shifted from the anterior horn of the medial meniscus to the anterior horn of the lateral meniscus.(3)In the knee extension position,applying a 4 N·m external rotation torque to the knee joint,the peak stress of the posterolateral meniscus increased more significantly than that of the medial meniscus,and the stress of the articular cartilage changed less.(4)These results show that the risk of meniscus injury secondary to superficial medial collateral ligament rupture is much higher than that of deep medial collateral ligament rupture when the knee is in extension,and the lateral meniscus is more vulnerable to injury than the medial meniscus.Both superficial medial collateral ligament and deep medial collateral ligament play an important role in the rotational stability of the knee joint.

Background and purpose:Hepatocellular carcinoma(HCC)is a major disease seriously threatening human health.Poly(ADP-ribose)polymerase-1(PARP1)is an enzyme that catalyzes poly ADP-ribosylation.Given the role of PARP1 in DNA damage repair,it is generally considered as an oncogene.However,the expression of PARP1 and its mechanism in HCC are not yet clear.This study aimed to investigate the role of PARP1 in the occurrence and development of HCC and its potential mechanisms.Methods:First,we analyzed the expression pattern of PARP1 in The Cancer Genome Atlas(TCGA)and Clinical Proteomic Tumor Analysis Consortium(CPTAC)HCC database,and identified the expression trend of PARP1 in our HCC cohort using real-time fluorescence quantitative polymerase chain reaction(RTFQ-PCR)and Western blot.Then,the enzyme activity of PARP1 was inhibited by PJ34,an inhibitor of PARP1 and the expression of PARP1 in HCC cell lines was downregulated with small RNA interference technology.Based on these models,the following experiments were conducted:First,the effect of PARP1 on cell viability was assessed by cell counting kit-8(CCK-8)assay and flow cytometry;Second,the expression levels of stemness-related genes in HCC cells were identified using RTFQ-PCR;Third,the effect of inhibition of PARP1 on migration and invasion of HCC cells was detected by migration and invasion assay(transwell assay).Finally,bioinformatic analysis was performed to identify new target genes and the pathways regulated by PARP1 in HCC progression.Rescue experiments were performed to determine whether PARP1 target genes were involved in the malignant phenotypes of HCC cells.Results:The expression of PARP1 was significantly up-regulated in HCC tissues in both TCGA and CPTAC database.RTFQ-PCR and Western blot assays showed that PARP1 was obviously up-regulated in HCC tissues compared to paracancerous tissues.Survival analysis showed that PARP1 expression was significantly negatively correlated with the prognosis of patients.The results of CCK-8,flow cytometry,RTFQ-PCR and transwell assay indicated that inhibition of PARP1 attenuated proliferation and activity of HCC cells,as well as weakened their stemness,migration and invasion.Bioinformatics analysis suggested that PARP1-regulated genes were enriched in the nuclear factor-κB(NF-κB)and necroptosis pathways,with POU class homeobox 2(POU2F2)potentially being a target gene of PARP1.Correlation analysis,along with RTFQ-PCR and Western blot detection,confirmed that the expression of POU2F2 was regulated by PARP1,while not affected by PJ34,indicating the effect of nonenzymatic function of PARP1 on POU2F2.CCK-8,flow cytometry and RTFQ-PCR results showed that the reintroduction of POU2F2 enhanced proliferative capacity,increased activity,and promoted stemness of HCC cell lines with PARP1 knockdown.Conclusion:By positively regulating the expression of POU2F2,PARP1 promotes malignant phenotypes of HCC cells,providing new insights for clinical treatment and drug development for HCC.

Medical physicists play an important role in the delivery of radiotherapy. Compared with China′s mainland, Hong Kong has established a more mature training mode and a more complete management system for medical physics talents. In this article, the authors introduced the current state of medical physics talent training, as well as the recruitment, certification and promotion of medical physicist in Hong Kong by querying the official websites of medical physics organizations, reviewing related literature and interviewing senior medical physicists in Hong Kong. The authors also analyzed the shortcomings in the construction of medical physics talent system in China′s mainland and made valuable suggestions.

OBJECTIVES: To compare the short-, mid-, and long-term outcomes in patients with esophageal cancer between minimally invasive esophagectomy via Sweet approach in combination with cervical mediastinoscopy (MIE-SM) and minimally invasive esophagectomy via McKeown approach (MIE-MC), and to evaluate the value of MIE-SM in the surgical treatment of esophageal cancer. METHODS: A prospective, nonrandomized study was adopted. A total of 65 esophageal cancer patients after MIE-SM and MIE-MC from June 2014 to May 2016 were included. Among them, 33 patients underwent MIE-SM and 32 patients underwent MIE-MC. Short-term outcomes (including the duration of surgery, intraoperative blood loss volume, ICU stay time, postoperative complications, postoperative hospital stay, reoperation, open surgery, number of dissected lymph nodes, and 30-day mortality), mid-term outcomes, [including Quality of Life Core Questionnaire (QLQ-C30) and the esophageal site-specific module (QLQ-OES18)], long-term outcomes [including overall survival and disease-free survival] were compared between the 2 groups. RESULTS: Radical resection (R0) were achieved in all patients. There were no significant differences in the duration of surgery, intraoperative blood loss volume, ICU stay time, postoperative complications, and postoperative hospital stay between the 2 groups (all CONCLUSIONS MIE-SM appears to be a safe surgical approach, which may get better quality of life, suffer less pain, and can achieve the same therapeutic effect as MIE-MC. Therefore, MIE-SM should be considered as a valuable approach for the treatment of middle and lower esophageal cancer.
Esophageal Neoplasms/surgery* ; Esophagectomy ; Humans ; Laparoscopy ; Mediastinoscopy ; Minimally Invasive Surgical Procedures ; Postoperative Complications/epidemiology* ; Prospective Studies ; Quality of Life ; Retrospective Studies ; Treatment Outcome

The training program of radiation therapists in the United States has been established early, and the mode of training, qualification and continuing education are relatively complete. Literature review was conducted at home and abroad and United States Department of Labor, American Registry of Radiologic Technologists, American Society of Radiologic Technologists as well as Joint Review Committee on Education in Radiologic Technology websites were reviewed. The training mode, qualification, work content, continuing education and employment situation of American radiotherapists were analyzed, aiming to provide some reference and enlightenment for the establishment of a new model for the training of professional radiologists suitable for the national conditions of China Mainland.

Objective: To explore the application value of CT imaging in differentiating gastric stromal tumors (GST) from gastric leiomyomas (GLMs). Methods: CT images of patients with GST (n=65) or GLMs (n=13, maximum diameter of tumor ≤5 cm) proved by surgery and pathology were retrospectively analyzed. The tumor size, location, contour, growth pattern, degree and pattern of enhancement, calcification, necrosis, surface ulceration, lymph nodes, and patient clinical data were evaluated by two independent reviewers. Receiver operating characteristic (ROC) curves were employed to assess the measurement and calculation parameters in the differentiation of GST and GLMs. Results: Between the GST and GLMs groups, there was no statistically significant difference in the contour, growth pattern, calcification, surface ulceration, and patient's sex (P>0.05). CT values of in plain scans, degree of enhancement in arterial phase (DE1), size, location and pattern of enhancement were found to be different between GST and GLMs (P<0.05). When the cutoff value of the maximum tumor diameter was 3.2 cm, the area under ROC curve, sensitivity and specificity were 0.707, 92.3%(12/13) and 60.6%(40/66), respectively. When the cutoff value of age was 59 years, the area under ROC curve, sensitivity and specificity were 0.773, 92.3% (12/13) and 46.2% (30/65), respectively. Taking the cutoff value of 10.9 HU as the degree of enhancement in arterial phase (DE1), the area under ROC curve, sensitivity and specificity were 0.774, 84.6% (11/13) and 77.3% (51/66), respectively. Using a cutoff value of 30.3 HU, the sensitivity, specificity, and the area under ROC curve were 84.6% (11/13), 65.2% (43/66), and 0.731, respectively. Conclusions CT examination in addition to clinical data can be very helpful for the differential diagnosis of GLMs from GSTs in maximum diameter ≤5 cm.

Objective: To evaluate the correlation between computed tomography (CT) features and malignancy risk category of small (≤5 cm) gastric stromal tumors (GST), in order to provide an image reference for preoperative assessment and intraoperative pathological diagnosis. Methods: Eighty-three patients with surgically and pathologically proven GST (≤5 cm) between January 2011 and November 2015 were recruited, and their clinical, pathological and CT data were retrospectively analyzed. According to the pathological results and malignancy risk category, the patients were divided into 2 groups, the benign biological behavior group (very low and low risk) and malignant biological behavior group (intermediate and high risk). The clinical, pathological and CT imaging findings of the two groups were analyzed. Based on the tumor diameter, the receiver operating characteristic curve (ROC) was applied to evaluate the sensitivity, specificity and the best cut-off point for distinguishing the malignancy risk between the two groups. Results: The lobulation and ulceration of the tumors presented statistically significant difference for the malignancy risk between the two groups (χ²=6.273 and 4.163, respectively; all P<0.05), but there was no significant difference in the sex, clinical symptoms, serum ferritin, tumor site, growth pattern, cystis degeneration and calcification (all P>0.05). No statistically significant differences were detected for the tumor CT value, arterial CT value, venous CT value, degrees of enhancement in arterial phase (DEAP), enhancement in portal venous phase (DEPP), and patient′s age for distinguishing the malignancy risk between the two groups (all P>0.05). On the other hand, significant differences were found in the maximum diameter (Dmax) of tumor and the minimum diameter (Dmin) of tumor (t=-3.256 and -3.466, respectively; all P<0.05). When the cut-off point of Dmax was 1.6 cm, the area under the ROC curve, sensitivity and specificity were 0.704, 92.3% and 75.4%, respectively. When the cut-off point of Dmin was 1.5 cm, the area under the ROC curve, sensitivity and specificity were 0.713, 88.5% and 71.9%, respectively. Conclusion CT features of the GST (≤5 cm) may predict, before surgery, the malignancy risk of small gastric stromal tumors, and provide the an image reference for preoperative assessment and intraoperative pathological diagnosis of the disease.

AIM: To verify the role of enhancing or suppressing the expression of glutathione peroxidase 1 (GPx1) in the growth, migration and invasion of glioblastoma multiforme cell lines U87MG and U118MG.METHODS:U87MG and U118MG cell lines were transfected with the vector containing specific siRNA or pcDNA3.1 recombinant plas-mid both targeting GPx1.The mRNA and protein expression levels of GPx1 were detected by real-time PCR and Western blotting.MTS assay was applied for determining the cell activity.The abilities of migration and invasion were examined by Transwell assay.RESULTS:Compared with blank control group and negative group, the inhibitory rate of the cell activity in U87MG cells in siRNA group was significantly reduced by 25.9%, 35.7%and 34.8%at 24 h, 48 h and 72 h, respec-tively (P<0.05).In contrast, the cell activity of U118MG cells in pcDNA3.1-GPx1 group was significantly increased by 22.7%, 45.8%and 39.8%at 24 h, 48 h and 72 h, respectively ( P<0.05) .In siRNA group, the inhibitory rate of mi-gration in U87MG cells was 41.6%±8.2%and the invasion was 41.6%±8.2%compared with blank control group and negative group (P<0.05).The cell migration and invasion rates of the U118MG cells in pcDNA-GPx1 group were in-creased by 55.8%±9.8% and 60.8% ±9.2%, respectively, compared with blank control group and negative group (P<0.05).CONCLUSION:The down-regulation of GPx1 by specific siRNA reduces the capability of cell growth, mi-gration and invasion of U87MG cells, while up-regulation of GPx1 by pcDNA3.1-GPx1 increases the capability of cell growth, migration and invasion of U118MG cells.

Objective To evaluate the clinical value of carbon nanoparticles suspension in gallbladder carcinoma lymphadenectomy.Methods 21 cases of gallbladder carcinoma who received radical resection from January 2008 to August 2013 were randomly divided into experimental group (11 cases received carbon nanoparticles injection into the subserosa around the tumor before operation) and control group (10 cases did not receive any tracer).The number of dissected lymph nodes,black-stained lymph nodes and positive lymph nodes were analyzed.Results A total of 138 lymph nodes were resected in experiment group,average 12.546±5.047 lymph nodes per patient,which was significantly more than that in control group in which there were overall 87 lymph nodes,average 8.700±2.497 lymph nodes per patient (t =2.176,P =0.042).The blacken rate of lymph nodes in experimental group was 56.522 ％ (78/138).There were 46 metastasis lymph nodes out of 79 blacken lymph nodes,and the positive rate was significantly higher than that of non-blacken lymph nodes [58.228 ％ (46/79) vs 38.983 ％ (23/59),P=0.039].There was no local or systemic adverse reaction occurred in experimental group.Conclusions Carbon nanoparticles suspension maybe helpful for lymphadenectomy during radical gallbladder carcinoma dissection to reduce operating damage and be safe.