Spatial distribution and risk assessment of heavy metals in contaminated paddy fields - A case study in Xiangtan City, southern China.

An extensive investigation on spatial distribution and environmental risk assessment based on total content and fractions of heavy metals, as well as the cancer risk of Cd from seven adjacent contaminated paddy fields at Xiangtan City, southern China, was conducted in this study. A total of 63 soil samples were analyzed for soil physical properties and concentrations of eight heavy metals (Cd, Cr, Co, Cu, Mn, Ni, Pb, Zn). The results showed that concentrations of metals except for Cr, Mn and Ni exceeded the background values to varying degrees, and particularly, content of Cd was as 57.4-612 times higher than background values. Principal components analysis and correlation analysis revealed three groups: industry activities for Cd and Zn; natural sources mainly for Cu, Pb, Ni and Cr, with some slight anthropogenic activities for Cu and Pb accumulation; and manganese ore associated with cobalt for Co and Mn. Combined with different indices, Cd and Zn were the major contributors to the ecological risk, and cancer risk of Cd indicated an unacceptable degree in this area. Altogether, results from this study will facilitate a better understanding of metals distribution characteristics and provide a scientific basis for further comprehensive management for these paddy fields. Combination of functional microbial agent and plants promises to be a feasible and effective remediation method for cadmium pollution in the study area.

Research on the epigenetic modification of pancreatic cancer vaccine.

Pancreatic cancer is characterized as a type of gastrointestinal tumor with a poor prognosis and high degree of malignancy. CIITA gene was found highly methylated in pancreatic carcinoma cell line PANC-1 and responsible for the low expression of MHC-II that may lead to immune evasion. Here, we tried to prepare pancreatic cancer vaccine with PANC-1 cells via epigenetic modification to enhance the MHC-II expression. Then the vaccine was injected into C57BL/6J mice and the effect was examined. Our study found that the vaccine could promote the proliferation of antigen-specific T cells, enhance the killing activity of cytotoxic lymphocytes (CTL), promote Th1-type cells mediated secretion of cytokines IFN-gamma and IL-2 while inhibiting Th2-type cells mediated secretion of IL-4, and inhibit the secretion of TGF-beta. Generally, the epigenetically modified vaccine could enhance the body's anti-tumor immune response, providing feasibility research on cancer vaccine for therapy of pancreatic cancer.

Exercise potentially prevents colorectal cancer liver metastases by suppressing tumor epithelial cell stemness via RPS4X downregulation.

Background: Colorectal cancer (CRC) is the third most prevalent tumor globally. The liver is the most common site for CRC metastasis, and the involvement of the liver is a common cause of death in patients with late-stage CRC. Consequently, mitigating CRC liver metastasis (CRLM) is key to improving CRC prognosis and increasing survival. Exercise has been shown to be an effective method of improving the prognosis of many tumor types. However, the ability of exercise to inhibit CRLM is yet to be thoroughly investigated. Methods: The GSE157600 and GSE97084 datasets were used for analysis. A pan-cancer dataset which was uniformly normalized was downloaded and analyzed from the UCSC database: TCGA, TARGET, GTEx (PANCAN, n = 19,131, G = 60,499). Several advanced bioinformatics analyses were conducted, including single-cell sequencing analysis, correlation algorithm, and prognostic screen. CRC tumor microarray (TMA) as well as cell/animal experiments are used to further validate the results of the analysis. Results: The greatest variability was found in epithelial cells from the tumor group. RPS4X was generally upregulated in all types of CRC, while exercise downregulated RPS4X expression. A lowered expression of RPS4X may prolong tumor survival and reduce CRC metastasis. RPS4X and tumor stemness marker-CD44 were highly positively correlated and knockdown of RPS4X expression reduced tumor stemness both in vitro and in vivo. Conclusion: RPS4X upregulation may enhance CRC stemness and increase the odds of metastasis. Exercise may reduce CRC metastasis through the regulation of RPS4X.

Combining the LKB NTCP model with radiosensitivity parameters to characterize toxicity of radionuclides based on a multiclonogen kidney model: a theoretical assessment.

The Lyman-Kutcher-Burman (LKB) normal tissue complication probability (NTCP) model is often used to estimate the damage level to normal tissue. However, it does not manifestly involve the influence of radiosensitivity parameters. This work replaces the generalized mean equivalent uniform dose (gEUD) with the equivalent uniform dose (EUD) in the LKB model to investigate the effect of a variety of radiobiological parameters on the NTCP to characterize the toxicity of five types of radionuclides. The dose for 50 % complication probability (D (50)) is replaced by the corresponding EUD for 50 % complication probability (EUD(50)). The properties of a variety of radiobiological characteristics, such as biologically effective dose (BED), NTCP, and EUD, for five types of radioisotope ((131)I, (186)Re, (188)Re, (90)Y, and (67)Cu) are investigated by various radiosensitivity parameters such as intrinsic radiosensitivity α, alpha-beta ratio α/ß, cell repair half-time, cell mean clonogen doubling time, etc. The high-energy beta emitters ((90)Y and (188)Re) have high initial dose rate and mean absorbed dose per injected activity in kidney, and their kidney toxicity should be of greater concern if they are excreted through kidneys. The radiobiological effect of (188)Re changes most sharply with the radiobiological parameters due to its high-energy electrons and very short physical half-life. The dose for a probability of 50% injury within 5y (D (50/5)) 28 Gy for whole-kidney irradiation should be adjusted according to different radionuclides and different radiosensitivity of individuals. The D (50/5) of individuals with low α/ß or low α, or low biological clearance half-time, will be less than 28 Gy. The 50 % complication probability dose for (67)Cu and (188)Re could be 25 Gy and 22 Gy. The same mean absorbed dose generally corresponds to different degrees of damage for tissues of different radiosensitivity and different radionuclides. The influence of various radiobiological parameters should be taken into consideration in the NTCP model.

[Therapeutic effects and complications of percutaneous pedicle screw fixation for thoracolumbar fractures].

OBJECTIVE: To investigate the therapeutic effects and complications of percutaneous pedicle screw fixation for thoracolumbar fractures. METHODS: From January 2002 to December 2008, 103 patients with thoracolumbar fractures were treated with percutaneous pedicle screw fixation, including 75 males and 28 females, the average age was 45.6 years (range, 18 - 72 years). All of them were of no neurological deficits. There were 65 cases of traffic injury, 23 cases of fall injury and 15 cases of smashed injury. According to the Denis classification, 64 patients were of compression fractures, and 39 patients of burst fractures. There were 5 cases had fractures in T(11), 30 in T(12), 42 in L(1), 15 in L(2), 4 in L(3), 3 in L(4), 2 in T(11-12), 1 in L(1-2), and 1 in L(2-3). Radiological examinations, including X-ray and CT examinations, and clinical examinations were carried out to evaluate the therapeutic effects. RESULTS: Twenty one patients were lost to follow up, the remaining were followed up from 10 to 48 months with an average of 27.4 months. Before the operation, the vertebral height, the kyphosis angle and the occupation of spinal canal were (54.5 ± 8.7)%, 16.4° ± 2.9° and 1.2 ± 1.0, and were improved to (88.6 ± 6.4)%, 11.6° ± 2.7° and 0.5 ± 0.6 respectively after the operation. Preoperatively the visual analogue scale and the Oswestry disability index were 8.0 ± 1.2 and 41.2 ± 9.3, and were improved to 1.7 ± 1.8 and 6.7 ± 5.6 postoperatively, respectively. All of these values between pre- and post-operatively were significantly different (P < 0.01). Screw misplacement was found in 7 patients, superficial wound infection in 1, screw breakage in 3, screw dislodgment in 2, cement leakage in 5, transient neurological symptoms in 4, and 8 patients with low back pain remained, of which 2 patients required occasional oral analgesics. Bone fusion achieved in all cases. CONCLUSIONS: The clinical efficacy of percutaneous pedicle screw fixation is similar with conventional open surgery. With the advantages of convenient procedure, less invasive, and rapid recovery, percutaneous pedicle screw fixation is an alternative method for thoracolumbar fractures without neurological deficits.

Supercapsular percutaneously assisted total hip arthroplasty versus conventional posterior approach: Comparison of early functional results.

OBJECTIVE: This study aimed to explore the early functional results of total hip arthroplasty (THA) using the supercapsular percutaneously assisted total hip (SuperPATH) microposterior approach. METHODS: In this retrospective study, 58 patients treated with THA from October 2015 to April 2016 in our hospital were enrolled. A total of 28 patients (11 men and 17 women; mean age: 74.95±7.06 years) were operated on using the SuperPATH approach (group 1), and the remaining 30 patients (12 men and 18 women; mean age: 75.63±7.89 years) were operated on using the conventional posterior approach (group 2). To summarize the early functional results of the SuperPATH approach, we retrospectively analyzed the following demographics, perioperative factors, and measures of joint function: age, sex, preoperative diagnosis, preoperative visual analog scale (VAS) for pain, body mass index, the American Society of Anesthesiologists physical status, operation time (skin-to-skin), intraoperative bleeding, incision length, postoperative VAS, Harris Hip Score (HHS), Barthel Index (BI), length of hospital stay, positioning of the implants, and postoperative complications. RESULTS: All 58 operations were successfully completed, and the average follow-up time was 45 (45.03±2.44) months. The patients in group 1 had shorter incision length (8.84±0.59 versus 13.26±2.41 cm) and length of stay (7.86±0.51 versus 10.80±1.93 days), lower postoperative VAS score (2.43±0.69 versus 3.13±0.94), and better postoperative HHS (88.37±4.31 versus 83.81±6.00) and BI (91.47±5.27 versus 83.59±6.83) at 3 months than the patients in group 2; however, group 1 patients had longer operation time (113.95±25.36 versus 87.22±25.43 min) than group 2 patients (all P<0.05). No significant intergroup differences were found with respect to intraoperative bleeding, cup abduction angle, anteversion angle, and stem positioning. During the follow-up, no deep venous thrombosis, postoperative infection, and hip dislocation were observed in any patient. CONCLUSION: Compared with the conventional posterior approach, the SuperPATH approach provided better early functional results with less postoperative pain and shorter hospitalization time. However, the operation time was longer in the SuperPATH approach group. LEVEL OF EVIDENCE: Level III, Therapeutic study.

Monte Carlo study of the influence of energy spectra, mesh size, high Z element on dose and PVDR based on 1-D and 3-D heterogeneous mouse head phantom for Microbeam Radiation Therapy.

PURPOSE: To evaluate the influence of energy spectra, mesh sizes, high Z element on dose and PVDR in Microbeam Radiation Therapy (MRT) based on 1-D analogy-mouse-head-model (1-D MHM) and 3-D voxel-mouse-head-phantom (3-D VMHP) by Monte Carlo simulation. METHODS: A Microbeam-Array-Source-Model was implemented into EGSnrc/DOSXYZnrc. The microbeam size is assumed to be 25µm, 50µm or 75µm in thickness and fixed 1mm in height with 200µmc-t-c. The influence of the energy spectra of ID17@ESRF and BMIT@CLS were investigated. The mesh size was optimized. PVDR in 1-D MHM and 3-D VMHP was compared with the homogeneous water phantom. The arc influence of 3-D VMHP filled with water (3-D VMHWP) was compared with the rectangle phantom. RESULTS: PVDR of the lower BMIT@CLS spectrum is 2.4times that of ID17@ESRF for lower valley dose. The optimized mesh is 5µm for 25µm, and 10µm for 50µm and 75µm microbeams with 200µmc-t-c. A 500µm skull layer could make PVDR difference up to 62.5% for 1-D MHM. However this influence is limited (<5%) for the farther homogeneous media (e.g. 600µm). The peak dose uniformity of 3-D VMHP at the same depth could be up to 8% for 1.85mm×1mm irradiation field, whereas that of 3-D VMHWP is<1%. The high Z element makes the dose uniformity enhance in target. The surface arc could affect the superficial PVDR (from 44% to 21% in 0.2mm depth), whereas this influence is limited for the more depth (<1%). CONCLUSION: An accurate MRT dose calculation algorithm should include the influence of 3-D heterogeneous media.

A voxel-dose algorithm of heterogeneous activity distribution for Monte-Carlo simulation of radionuclide therapy dosimetry.

PURPOSE: The organ or tumor activity is not uniform due to inhomogeneous expression/distributions of receptors/antigens and the nonuniform vascularization of the tumor tissue. However, most patient-specific three-dimensional Monte-Carlo methods for radionuclide dosimetry have dealt with quasi-homogeneous activity distributions. A voxel-by-voxel activity sample algorithm (VM) without artifacts is presented to calculate the dose of the heterogeneous activity distribution for radionuclide dosimetry. METHODS: The source particle location is sampled according to the activity spatial distribution. The source particle weight is imparted by the relative activity concentration of its origination voxel. This algorithm is applied to calculate the dose volume histogram for multiple independent activity regions with Gauss diffusion activity distributions and then compared with the level partition method (LM). The minimal response and the mean tolerant initial total activity threshold required by tumor control probability and normal tissue complication probability for radioimmunotherapy ((131)I-RIT) also were evaluated by the voxel-by-voxel sample algorithm and the LM. The effective clearance half-time is assumed to be equal to its physical half-life (i.e., 8.02 days for (131)I). RESULTS: The result shows that the new algorithm is more consistent with the weighted superposition of the quasi-homogeneous activity distribution than the LM, especially for the multiple independent activity regions composed of different amounts of voxels. The new algorithm effectively avoids the leveling/binning artifacts to the heterogeneous activity distribution. The (131)I-RIT simulation also showed that the minimal response initial total activity threshold of tumors will be much more than the mean tolerant initial total activity threshold of normal organs (e.g., kidney) with the activity heterogeneous grade deteriorating. CONCLUSIONS: A VM is presented to simulate the dose of the heterogeneous activity distribution for radionuclide dosimetry. The new algorithm effectively avoids the leveling/binning artifacts to the heterogeneous activity distribution.

[Analysis of outcome and prognostic factors of anterior approach for two-level cervical spondylotic myelopathy].

OBJECTIVE: To investigate the efficacy and possibly prognositic factors of anterior approach on two-level cervical spondylotic myelopathy. METHODS: A retrospective review was performed on 44 cases of two-level cervical spondylotic mydopathy from Jun. 2007 to Sep. 2009. Among the patients, 24 cases were male and 20 cases female, with an average age of (60.072 +/- 10.77) years (ranged from 39 to 80 years). The affected segments ranged from C(3.4)-C(6.7). Improvements of cervical curvature and segmental height, preoperative sagittal diameter of the spinal cord at the site of maximal compression and signal intensity changes on T2WI were respectively measured. Function of nerves was assessed according to Japanese orthopaedic association system (JOA:17 score) before and after surgery. Operation by anterior approach including: anterior corpectomy and titanium cage fusion with internal fixation, anterior corpectomy body and auto iliac bone fusion with internal fixation. Statistical analysis was made on the correlation between JOA recovery rate and prognostic factors. RESULTS: Improvements of cervical curvature was -9.1 degrees to 16.6 degrees with the mean of (1.30 +/- 5.77) degrees and improvements of segmental height was -0.3 to 12.3 mm with the mean of (4.23 +/- 3.08) mm. Sagittal diameter of the spinal cord at the site of maximal compression was 1.6 to 7.2 mm with the mean of (4.01+/- 1.25) mm. T2WI with high signal changes was in 29 cases, no change in 15 cases. Bleeding amount was 50 to 700 ml with the mean of (242.05 +/- 148.22) ml. Operative time was 90 to 250 min with the mean of (153.75 +/- 34.54) min. All patients were followed up from 6 to 31 months with an average of (17.18 +/- 7.41) months. The mean JOA score preoperatively was (12.73 +/- 2.23); at the final follow-up, the JOA score was(15.09 +/- 1.91); and the recovery rate was (60.01 +/- 26.98)%. According to standard of JOA scoring, 16 cases obtained excellent result, 12 good, 15 fair and 1 poor. The effect of anterior approach had correlations with age, time of course, preoperative JOA score, sagittal diameter of the spinal cord at the site of maximal compression and signal intensity changes on T2WI, but had no correlations with operation time, bleeding amount and improvements of cervical curvature and segmental height. CONCLUSION: Two-level cervical spondylotic myelopathy can achieve good effect through anterior approach. The extent of the spinal cord compression may be a reliable and direct factor to judge effect.