Objective To examine the effect of intrathecal administration of nerve growth factor (NGF)on healing of tibial shaft fracture in rats. Methotis Forty-eight adult male SD rats were randomized into 2 equal groups.In the experiment group,2.5 S mNGF was injected into the intrathecal space at the L1 level of spinal cord for 2 weeks(1 μg/day),while the control were treated with normal saline of the same amount.After injection,the animals in both groups were sacrificed respectively at days 7,14,21 and 28 for all X-ray evaluation on the bone callus and an immunohistochemistry assay on related dorsal root ganglia (DRG)and osteotylus. Results The immunoreactivity of calcitonin gene-related peptide(CGRP)and substance P(SP)in DRG and osteotylus was significantly hisher in the NGF group than in the saline-treated controls.X-ray CValuation of osteotylus 21 to 28 days after fracture scored lower in the NGF group than in the controls but the healing process was enhanced in the former.A hisher proportion of cartilage was found in the NGF group than in the controls,and the reconstruction of callus was promoted. Conclusion Stimulating the release of sensory neuropeptides in the rat spinal cord and enhancing the immunoreactivity of CGRP and SP in DRG and callus.NGF Can result in accelerated fracture healing.

Objective: To investigate the correlation between eukaryotic translation initiation factor 3, subunit A (eIF3a) and human epididymis protein 4 (HE4) expression and ovarian cancer. Methods: RT-PCR or immunohistochemistry was used to examine eIF3a and HE4 mRNA or protein expression in ovarian tissues from patients with ovarian cancer (n=181) or benign ovariantumors, or from the healthy women. Results: hTere were signiifcant differences in mRNA and protein expression of eIF3a and HE4 among normal ovarian tissues, benign ovarian tumor tissues, and ovarian cancer tissues (P<0.05). hTere were signiifcant differences in mRNA expression of eIF3a and HE4 between the normal tissues and the ovarian cancer tissues, or between the benign ovarian tumor tissues and the normal tissues (P<0.001). hTe mRNA expression of eIF3a in the normal ovarian tissues was signiifcantly higher than that in the benign ovarian tumor tissues or that in the ovarian cancer tissues. hTe mRNA expression of HE4 was gradually increased from the normal ovarian tissues, the benign ovarian tumor tissues to the ovarian cancer tissues. hTe mRNA expression of HE4 in the ovarian cancer tissues was signiifcantly higher than that in the benign ovarian tumor tissues (P<0.001). Positive expression rates for eIF3a or HE4 protein in normal, benign tumor, and cancer tissues were 0, 66.7%, and 81.0% or 0, 27.8%, and 56.2%, respectively. hTere were signiifcant differences in positive expression rates of eIF3a protein and HE4 protein between the ovarian tumor tissues and benign ovarian tumor tissues, between the ovarian cancer tissues and the normal ovarian tissues, or between the benign ovarian tumor tissues and the normal ovarian tissues (P<0.001). hTe eIF3a protein expression was positively correlated with HE4 protein expression (r=0.575,P<0.05). Conclusion: The expressions of eIF3a and HE4 are associated with ovarian cancer, and extracellular regulated protein kinases may play a role in the interaction between eIF3a and HE4.

Objective:To solve the problems in intensity-modulated radiation therapy (IMRT) planning, such as large labor cost and high dependence on the experience of physicists and great inconsistency in the quality of plan, and to discuss an unsupervised automatic treatment planning procedure of IMRT.Methods:The eclipse scripting application programming interface (ESAPI) within the Eclipse treatment planning system (TPS) 15.6 and optimization parameters tree search algorithm (OPTSA) were used to emulate and realize the whole planning process. Interacted with the TPS through ESAPI, relevant dosimetric parameters were input and output. The OPTSA evaluated the plan qualities based on dosimetric parameters of the targets and organs at risk (OARs) and iteratively adjusted the optimization objective parameters to achieve a progressively improving IMRT plan. In order to verify the effectiveness of the automatic planning, twenty historical rectum cancer cases were selected from the clinical database, and the dose distribution and specific dosimetric parameters were compared between the plans generated by the OPTSA and the manual plans under the same constraints.Results:All the auto plans have met clinical requirements. Furthermore, 90% and 10% of the auto plans were deemed as clinically improved and equally compared with the manual plans, respectively. The average CI for the PTV was 0.88 and 0.80 for the auto and manual plans respectively. Compared with the manual plans, the mean doses of all the OARs in the auto plans were reduced by 11% in average. The average elapsed time of automatic planning and manual planning was (28.15±3.61) and (36.7±4.6) min, respectively.Conclusions:The plans created by the proposed algorithm have been shown to be at least as good as the manual plans. In addition, this method can shorten the labor time in plan designing while ensuring the plan quality and consistency of the plan.

Objective:To investigate the performance of W2 plastic scintillator in megavolt photon and electron beams.Methods:The photon and electron beam energy provided by linear accelerator was used to collect data of the W2 scintillator. The parameters include the electrometer reading stability, W2 dose and dose rate linearity, and angular response. And the dose uncertainty of the W2 correction factors was also investigated.Results:The standard deviation of the electrometer reading stability was between 0.03 and 0.47. The linear regression factors of W2 dose were all 1.0; the maximum deviation of the dose rates was 0.61%. The Cerenkov light radiation correction factor(CLR) for 6 and 10 MV were 0.741 and 0.746, respectively, and the CLR for 6, 9, 12 and 15 MeV were 0.750, 0.753, 0.757 and 0.757, respectively. The maximum deviation of dose uncertainty for 15 MeV was 3.15%.Conclusions:The signal obtained by the blue and green channel was no angular dependence, the same as the high-energy electron beam, which verified that the Cerenkov radiation correction factor has good linearity. W2 plastic scintillator can be applied to non-coplanar radiotherapy dosimetry.

Objective To evaluate the clinical significance of high frequency ultrasound in the diagnosis of duodenal obstruction in neonates.Methods Ultrasonography,clinical data and etiological diagnoses of the operation in 113 neonates with duodenal obstruction were reviewed retrospectively.The digestive tract,including stomach,duodenum,jejunoileum and colon,were examined in all patients with 8-12 MHz linear transducer before operation.Results In the 113 neonates with duodenal obstruction,63 cases were diagnosed intestinal malrotation,31 cases duodenal stenosis,14 cases annular pancreas,and 5 cases duodenal atresia.One hundred and six cases were diagnosed as duodenal obstruction by ultrasound,of which intestinal malrotation in 61 cases,duodenal stenosis in 29 cases,duodenal atresia in 4 cases,and annular pancreas in 12 cases.The diagnostic rate was 93.81% (106/113 cases),96.83% (61/63 cases),93.55% (29/31 cases),80.00% (4/5cases) and 85.71% (12/14 cases),respectively.The location of obstruction diagnosed by ultrasound was coincident with the operation in 92 cases,with a diagnostic rate of 81.42%(92/113).Conclusions High frequency ultrasound plays an important role in diagnosing the causes and location of duodenal obstruction.It can be used as the first choice of examinal methods for the neonates with duodenal obstruction.

Objective To compare the stress distributions on the anterior horn,body part and posterior horn of menisci between the normal and the injured knees with anterior cruciate ligament (ACL) deficiency using the three-dimensional finite element analysis.Methods A three-dimensional finite element model of tibiofemoral joint was created to simulate the motion states of the normal and ACL-deficiency knees at extension,as well as 15° and 30° flexions.Meanwhile,700N axial load and 134N posterior load were applied to the femur.Then,the stress on the anterior horn,body part and posterior horn of medial and lateral menisci were compared between the normal and ACL-deficient knees.Results With ACL deficiency,when stretching the knees straightly,the stress on the anterior horn of medial meniscus increased to 100.7％ of the normal knees,bigger than that of the affected lateral meniscus (30.7％).At 15° and 30° flexions,the stress on the posterior horn of the medial meniscus in ACL-deficiency knees increased by 36.4％ and 59.7％ respectively when compared to normal knees,while the stress on that of the lateral meniscus did not increase significantly.Apart from the stress on the body part of the lateral meniscus increasing by 39.5％ at extension in ACL-deficiency knees,no obvious changes were observed in the stress on the body part of the medial and lateral menisci.Conclusion ACL deficiency has different effect on the stress of different parts of the meniscus.It mainly increases the stress on the anterior horn of the medial meniscus at extension and that of the posterior horn of the medial meniscus at flexion.

The American Transplant Congress (ATC) is an influential academic congress in the field of organ transplantation. In this article, the hotspots of liver transplantation in 2020 ATC were summarized, including the latest research progress in donor liver procurement and quality assessment, donor liver preservation and ischemia-reperfusion injury (IRI), liver transplantation for hepatocellular carcinoma and other hepatic malignancies, complications after liver transplantation, transplantation immunology, perioperative management and donor-derived infection, pediatric liver transplantation and cell therapy, etc.

Objective:To develope an automatic volumetric modulated arc therapy (VMAT) planning for rectal cancer based on a dose-prediction model for organs at risk(OARs) and an iterative optimization algorithm for objective parameter optimization.Methods:Totally 165 VMAT plans of rectal cancer patients treated in Peking University Cancer Hospital & Institute from June 2018 to January 2021 were selected to establish automatic VMAT planning. Among them, 145 cases were used for training the deep-learning model and 20 for evaluating the feasibility of the model by comparing the automatic planning with manual plans. The deep learning model was used to predict the essential dose-volume histogram (DVH) index as initial objective parameters(IOPs) and the iterative optimization algorithm can automatically modify the objective parameters according to the result of protocol-based automatic iterative optimization(PBAIO). With the predicted IOPs, the automatic planning model based on the iterative optimization algorithm was achieved using a program mable interface.Results:The IOPs of OARs of 20 cases were effectively predicted using the deep learning model, with no significantly statistical difference in the conformity index(CI) for planning target volume(PTV)and planning gross tumor volume(PGTV)between automatic and manual plans( P>0.05). The homogeneity index (HI) of PGTV in automatic and manual plans was 0.06 and 0.05, respectively( t=-6.92, P< 0.05). Compared with manual plans, the automatic plans significantly decreased the V30 for urinary bladder by 2.7% and decreased the V20 for femoral head sand auxiliary structure(avoidance)by 8.37% and 15.95%, respectively ( t=5.65, 11.24, P< 0.05). Meanwhile, the average doses to bladder, femoral heads, and avoidance decreased by 1.91, 4.01, and 3.88 Gy, respectively( t=9.29, 2.80, 10.23, P< 0.05) using the automatic plans. The time of automatic VMAT planning was (71.49±25.48)min in 20 cases. Conclusions:The proposed automatic planning based on dose prediction and an iterative optimization algorithm is feasible and has great potential for sparing OARs and improving the utilization rate of clinical resources.

Objective:To assess the three-dimensional dose distribution in radiotherapy plans using the structural similarity index(SSIM), compare the performance of SSIM with commonly used quality assessment indices, and develop a SSIM-based quality assessment method of multiple prescribed doses.Methods:The SSIM was introduced to providea quality score of various voxels by comparing actual and ideal three-dimensional dose data and combining the spatial location information of the voxels. Then the average value in a region of interest (ROI) was calculated as the quality score of the region. Fifty-three cases of cervical cancer were selected to analyze the correlation of the SSIM with the uniformity index (HI), conformity index (CI) of the dose distribution in various ROIs and to explore the capability of the SSIM to reflect the uniformity and conformity of dose distribution.Two types of quality defects were individually introduced into two of 53 radiotherapy plans. Then the two plans were compared with normal plans to characterize the response of the SSIM.Results:There was no correlation between HI and SSIM in positive lymph nodes(PGTVnd) due to the decrease in the HI sensitivity, while there was a significant negative correlation between them in regions where PGTVnd was removed from the planning target volume(PTV, R=-0.86, P<0.01). Meanwhile, there was a significant positive correlation between CI and SSIM in PGTVnd ( R=0.83, P<0.01). Therefore, the SSIM can be used to identify the artificial design defects in plans by determining abnormal dose gradients. Conclusions:Apart from reducing the defects of previous assessment parameters, the SSIM has the capability to assess the quality of radiotherapy plans by combining the uniformity and conformity of dose distribution and can provide accurate feedback on the spatial locations of quality defects.

Objective To evaluate the effect of microvascular invasion (MVI) on prognosis of recipients after liver transplantation for primary liver cancer (liver cancer). Methods Clinical data of 177 recipients after liver transplantation for liver cancer were retrospectively analyzed. All patients were divided into the MVI-positive group (n=64) and MVI-negative group (n=113) according to postoperative pathological examination results. Clinical data were statistically compared of all recipients between the negative and positive MVI groups. The prognosis and risk factors of liver transplantation recipients for liver cancer were analyzed. Results Among 177 recipients, 64 cases (36.2%) were positive for MVI and 113 (63.8%) negative for MVI. Compared with the MVI-negative recipients, MVI-positive recipients had significantly lower degree of tumor differentiation, higher preoperative alpha-fetaprotein (AFP) level, larger maximal tumor diameter, a larger quantity of tumors, more satellite lesions and more recipients who did not meet the Milan criteria (all P < 0.05). The 1-, 3- and 5-year overall survival (OS) and recurrence-free survival (RFS) of recipients after liver transplantation for liver cancer were 80.2%, 62.1%, 58.5% and 66.3%, 57.5%, 51.2%, respectively. The 1-, 3- and 5-year OS and RFS of MVI-positive recipients were 70%, 39%, 35% and 53%, 39%, 33%, significantly lower than 86%, 75%, 72% and 73%, 68%, 63% of their counterparts negative for MVI (all P < 0.05). Cox regression analysis showed that the maximal tumor diameter >8 cm, preoperative AFP level ≥20 ng/mL, low degree of tumor differentiation and positive MVI were the independent risk factors for OS of recipients after liver transplantation for liver cancer (all P < 0.05). Positive MVI, low degree of tumor differentiation and preoperative down-staging failure were the independent risk factors for RFS of recipients after liver transplantation for liver cancer (all P < 0.05). Conclusions MVI is of significant clinical value in predicting clinical prognosis of recipients after liver transplantation for liver cancer.