Re-watering solution facilitates seed germination and seedling growth of Carex schmidtii: Implication for species re-introduction in degraded semi-arid wetlands.

Water deficiency threatens the health and function of wetlands in semi-arid areas. Optimum re-watering is an effective method for close-to-natural restoration to mitigate wetland degradation. Although the ecological importance of optimal re-watering as a nature-based solution for promoting wetland plant growth has been widely recognized, the response mechanisms of seed germination and seedling growth to re-watering are still poorly understood despite their decisive impact on plant life history. To fill this gap, this study compared the characteristics of seed germination and seedling growth in Carex schmidtii under initial water content with three levels (30%, 50%, and 70%) and five re-watering treatments (maintained at constant water content and re-watering to 100% on 7th, 14th, 21st, and 28th day). Moreover, the degree of reserve mobilization during four germination stages (seed suckering, sprouting, 20% germination, and seedling growth) was investigated. The results showed that water deficiency and re-watering treatments significantly affected C. schmidtii seed germination, seedling growth, and reserve mobilization. Compared with the other treatments, 50% moisture content and re-watering to 100% on the 14th day (50%-RT3) treatment significantly improved germination traits (germination rate, daily germination rate, germination index, and vigor index) and seedling growth characteristics (shoot length, root length, shoot biomass, root biomass, and total biomass). Furthermore, the degree of mobilization of starch, soluble protein, fat, and soluble sugar accumulation in C. schmidtii seeds under 50%-RT3 was higher than that in the other treatments. The structural equation model showed that the characteristics of seed germination and seedling growth of C. schmidtii were directly related to water deficiency and re-watering treatments, whereas reserve mobilization indirectly affected seed germination and seedling growth. These findings demonstrated that water deficiency and re-watering treatments have a crucial regulatory effect on seed germination and seedling growth of wetland plant species through a dual mechanism. This study provides information for the formulation of an optimum re-watering strategy for wetland vegetation restoration in semi-arid areas of the world.

Biogeochemical zonation of sulfur during the discharge of groundwater to lake in desert plateau (Dakebo Lake, NW China).

As one of the important elements of controlling the redox system within the hyporheic and hypolentic zone, sulfur is involved in a series of complex biogeochemical processes such as carbon cycle, water acidification, formation of iron and manganese minerals, redox processes of trace metal elements and a series of important ecological processes. Previous studies on biogeochemistry of the hyporheic and hypolentic zones mostly concentrated on nutrients of nitrogen and phosphorus, heavy metals and other pollutants. Systematic study of biogeochemical behavior of sulfur and its main controlling factors within the lake hypolentic zone is very urgent and important. In this paper, a typical desert plateau lake, Dakebo Lake in northwestern China, was taken for example within which redox zonation and biogeochemical characteristics of sulfur affected by hydrodynamic conditions were studied based on not only traditional hydrochemical analysis, but also environmental isotope evidence. In the lake hypolentic zone of the study area, due to the different hydrodynamic conditions, vertical profile of sulfur species and environmental parameters differ at the two sites of the lake (western side and center). Reduction of sulfate, deposition and oxidation of sulfide, dissolution and precipitation of sulfur-bearing minerals occurred are responded well to Eh, dissolved oxygen, pH, organic carbon and microorganism according to which the lake hypolentic zone can be divided into reduced zone containing H2S, reduced zone containing no H2S, transition zone and oxidized zone. The results of this study provide valuable insights for understanding sulfur conversion processes and sulfur biogeochemical zonation within a lake hypolentic zone in an extreme plateau arid environment and for protecting the lake-wetland ecosystem in arid and semiarid regions.

Effects of Hindlimb Unweighting on MBP and GDNF Expression and Morphology in Rat Dorsal Root Ganglia Neurons.

With the development of technology and space exploration, studies on long-duration space flights have shown that microgravity induces damage to multiple organs, including the dorsal root ganglia (DRG). However, very little is known about the effects of long-term microgravity on DRG neurons. This study investigated the effects of microgravity on lumbar 5 (L5) DRG neurons in rats using the hindlimb unweighting (HU) model. Male (M) and female (F) Sprague-Dawley rats were randomly divided into M- and F-control (CON) groups and M- and F-HU groups, respectively (n = 10). At the end of HU treatment for 4 weeks, morphological changes were detected. Myelin basic protein (MBP) and degenerated myelin basic protein (dgen-MBP) expressions were analyzed by immunofluorescence and western blot assays. Glial cell line-derived neurotrophic factor (GDNF) protein and mRNA expressions were also analyzed by immunohistochemistry, western blot, and RT-PCR analysis, respectively. Compared with the corresponding CON groups, the HU groups exhibited slightly loose junctions between DRG neurons, some separated ganglion cells and satellite cells, and lightly stained Nissl bodies that were of smaller size and had a scattered distribution. High levels of dgen-MBP and low MBP expressions were appeared and GDNF expressions were significantly decreased in both HU groups. Changes were more pronounced in the F-HU group than in the M-HU group. In conclusion, HU treatment induced damage of L5 DRG neurons, which was correlated with decreased total MBP protein expression, increased dgen-MBP expression, and reduced GDNF protein and mRNA expression. Importantly, these changes were more severe in F-HU rats compared with M-HU rats.

Optimal chin-brow vertical angle for sagittal visual fields in ankylosing spondylitis kyphosis.

PURPOSE: Chin-brow vertical angle (CBVA) is very important in correction of thoracolumbar kyphotic deformity in ankylosing spondylitis (AS), especially for the patients with cervical ankylosis. In previous study, Suk et al. stated that the patients with CBVA between -10° and 10° had better horizontal gaze. Unfortunately, in our clinical practice, we found the patients with CBVA between -10° and 10° after surgery usually complained of difficulty in cooking, cleaning, desk working and the like, although they had excellent horizontal gaze. In other words, for the patients with cervical ankylosis, good horizontal gaze existed together with poor downward gaze. Then, which condition do the patients prefer? Is there a compromise solution that makes a better quality life possible for the patients? In this research, we studied AS patients with cervical ankylosis, aiming to investigate the optimal CBVA for deformity correction. METHODS: 25 AS thoracolumbar kyphotic patients with cervical ankylosis were studied, whose function and expectation of visual field related to life quality were assessed by questionnaire before and after surgery. Pre- and post-operative CBVA were obtained on lateral photos of the patients with free-standing posture, and 50 cases of CBVA were included, which were divided into six groups according to the angle irrespective of surgery (Group A, CBVA <0°; Group B, 0° ≤ CBVA < 10°; Group C, 10° ≤ CBVA < 20°; Group D, 20° ≤ CBVA < 30°; Group E, 30° ≤ CBVA < 40°; Group F, CBVA ≥ 40°). Kruskal-Wallis test was used to assess all the groups in terms of various items in the questionnaire, while Mann-Whitney test was used to assess every two groups. RESULTS: In overall evaluation, Group C (10°-20°) obtained the optimal expectation (p < 0.05); Group B, C and D (0°-30°) obtained better function (p < 0.05), and there was no significant difference between the 3 groups. In appearance, Group A, B and C (<20°) were better than the other groups both in function and expectation (p < 0.05), without dramatic difference among the three groups. In outdoor activities, Group A, B, C and D (<30°) were better in most of the items (p < 0.05). In indoor activities, Group C and D (10-30°) were much better (p < 0.05). CONCLUSION: AS thoracolumbar kyphotic patients with cervical ankylosis had the best satisfaction when 10° ≤ CBVA < 20°.

Simulated microgravity-induced mitochondrial dysfunction in rat cerebral arteries.

Exposure to microgravity results in cardiovascular deconditioning, and cerebrovascular oxidative stress injury has been suggested to occur. To elucidate the mechanism for this condition, we investigated whether simulated microgravity induces mitochondrial dysfunction in rat arteries. Four-week hindlimb unweighting (HU) was used to simulate microgravity in rats. Mitochondrial reactive oxygen species (ROS), mitochondrial membrane potential (Δψm), mitochondrial permeability transition pore (mPTP) opening, mitochondrial respiratory control ratio (RCR), MnSOD/GPx activity and expression, and mitochondrial malondialdehyde (MDA) were examined in rat cerebral and mesenteric VSMCs. Compared with the control rats, mitochondrial ROS levels, mPTP opening, and MDA content increased significantly (P<0.001, P<0.01, and P<0.01, respectively), Δψm, RCR, MnSOD/GPx activity (P<0.001 for Δψm and RCR; P<0.05 for MnSOD; and P<0.001 for GPx activity) and protein abundance of mitochondrial MnSOD/GPx-1 decreased (P<0.001 for MnSOD and GPx-1) in HU rat cerebral but not mesenteric arteries. Chronic treatment with NADPH oxidase inhibitor apocynin and mitochondria-targeted antioxidant mitoTempol promoted recovery of mitochondrial function in HU rat cerebral arteries, but exerted no effects on HU rat mesenteric arteries. Therefore, simulated microgravity resulted in cerebrovascular mitochondrial dysfunction, and crosstalk between NADPH oxidase and mitochondria participated in the process.

Effect of Preoperative Tracheal Stretch Exercise on Anterior Cervical Spine Surgery: A Retrospective Study.

STUDY DESIGN: We designed a retrospective study on preoperative tracheal stretch exercise (TSE) before anterior cervical spine surgery. The changes in vital signs before and during the surgery and the postoperative clinical outcome were recorded and compared with none treated patients. OBJECTIVE: The aim of this study was to evaluate whether the preoperative TSE is beneficial to the anterior cervical spine surgery and clinical outcome. SUMMARY OF BACKGROUND DATA: Anterior approach to the cervical spine surgery requires prolonged retraction of the trachea and esophagus. Although the surgery can be managed to complete, related potential complications may occur. METHODS: This is a retrospective study on 128 patients scheduled for anterior cervical spine surgery. Patients in the stretched group received preoperative TSE for 3 consecutive days before surgery, whereas the control group did not. During the preoperative exercise and the surgery, the changes in the vital signs were recorded and compared with the control group. The visual analogue scale, neck disability index (NDI), and the Clinical Symptom Score of the Japanese Orthopaedic Association (JOA) were also compared at different follow-up intervals, including 1, 3, and 6 months postoperation. RESULTS: The changes in blood pressure, heart rate, and respiratory and swallowing rates during the first exercise are significantly greater than those during the last exercise (P<0.05). During the surgery, changes in the vital signs in the exercise patients are also significantly smaller than those in control patients (P<0.05), excluding the blood oxygen saturation. The significant differences were also observed with the postoperative NDI and JOA scores between the exercise and control group at 6 months (P<0.05). CONCLUSIONS: Proper and systematic preoperative TSE has great significance for the success of anterior cervical spine surgery.

ARHI overexpression induces epithelial ovarian cancer cell apoptosis and excessive autophagy.

OBJECTIVE: ARHI is a maternally imprinted tumor suppressor gene that is responsible for initiating programmed cell death and inhibiting cancer cell growth. However, the influence of ARHI on epithelial ovarian cancer cell death and the underlying mechanisms behind how ARHI regulates cancer cells still require further studies. METHODS: Epithelial ovarian cancer cells TOV112D and ES-2 were used in this in vitro study. Cell proliferation, apoptosis, and autophagy activities were compared in TOV112D and ES-2 cells transfected with ARHI vectors or control vectors. Bcl-2 siRNA was transfected into TOV112D cells to investigate the roles of Bcl-2 played in regulating apoptosis and autophagy. RESULTS: ARHI expression was reduced in TOV112D and ES-2 cells compared with normal epithelial ovarian cells (NOE095 and HOSEpiC). Overexpressed ARHI inhibited cancer cell proliferation, whereas induced forced cell apoptosis and excessive formation of autophagosomes inhibited promoted cell death. Furthermore, we found that Bcl-2 expression moderately declined in response to ARHI overexpressing in ES-2 and TOV112D cells; meanwhile, more apoptotic cells and higher LC3 level presented after silence of Bcl-2 in TOV112D cells. Reduced Bcl-2-Beclin 1 complex were observed in ARHI overexpressing cells. Moreover, modulation of ARHI to Bcl-2 expression could be ascribed partially to the activation of PI3k/AKT pathway. The addition of LY294002 enabled to suppress Bcl-2 expression and cell proliferation. CONCLUSIONS: The silence of ARHI expression in vitro seems to accelerate the malignant transformation of healthy ovarian cells by restraining apoptosis and autophagy. The overexpressed ARHI in TOV112D cancer cells suppresses the activation of PI3K/AKT and reduces the expression of Bcl-2, leading to enhanced cell apoptosis and autophagic cancer cell death.

Hilus pulmonis as the center of gravity for AS thoracolumbar kyphosis.

INTRODUCTION: The sagittal vertical axis (SVA) is a meaningful measurement and widely used for evaluating sagittal balance, and is considered a design standard for surgery, including most ankylosing spondylitis (AS) kyphotic deformity planning. However, recent research indicates that the C7 plumb line is actually not the center of gravity (CG) line. Therefore, whether there is a better radiological marker as the CG of the trunk for AS thoracolumbar kyphosis remains unknown. This research is to investigate a radiological marker for the CG of the trunk in lateral radiographs for AS thoracolumbar kyphosis. MATERIALS AND METHODS: The center of gravity of an irregular object can be obtained by hanging or supporting it in different points and directions, and the CG will be on the point of intersection. According to this principle of mechanics, we could use the pre- and post-operative hip axis vertical lines to locate the CG of the trunk. We evaluated 38 AS-fixed thoracolumbar kyphotic patients with pedicle subtraction osteotomies. Full-length, free-standing lateral radiographs, including the spine and pelvis, were available for all patients. Pre- and post-operative radiological parameters were measured, including SVA, horizontal distance between hip axis and C7 (HDHC), horizontal distance between hip axis and T5 (HDHT5), horizontal distance between hip axis and T9 (HDHT9), and horizontal distance between hip axis and hilus pulmonis (HDHH). Pre- and post-operative radiological parameter changes were compared by paired samples t tests. The intraclass correlation coefficient (ICC) was used to determine the intra- and interobserver reliabilities of HDHH. RESULTS: Pre-operative SVA, HDHC, HDHT5, HDHT9, and HDHH values were, respectively, 21.1, 12.7, 3.5, -3.8, and 2.7 cm, and their post-operative values were, respectively, 9.1, 4.2, -2.1, -5.6, and 0.9 cm. Changes in SVA, HDHC, HDHT5, and HDHT9 were significant (p < 0.05), while the change in HDHH was not (p > 0.05). The ICC for overall interobserver reliability was 0.958 (p < 0.001), and it was 0.963 (p < 0.001) for overall intraobserver reliability. CONCLUSION: The hilus pulmonis fell approximately on the hip axis both pre- and post-operatively. It was a better marker as the center of gravity of the trunk for deformity planning for AS thoracolumbar kyphosis.

Hydrological and biogeochemical processes controlling riparian groundwater quantity and quality during riverbank filtration.

Groundwater exploitation in a riparian zone causes water infiltration from the river into the aquifer. Owing to adsorption and redox reactions along the flow path, the quality of water flowing from the river to groundwater wells is variably altered. The riverbed composition often involves spatiotemporal differences due to frequent changes in hydrological conditions. These changes create uncertainties in the transport and removal of solutes in the river water. In this study, the hydrodynamic field associated with riparian groundwater, changes in the structure of riverbed sediments caused by erosion and deposition, fluctuations in surface water and groundwater levels, and the removal efficiency of pollutants from groundwater through pumping were investigated. This involved in situ monitoring and sample testing of the composition of the river water, riverbed sediments, riverbed pore water, and groundwater during dry and wet seasons. Implementation of field in situ column experiments and molecular biology evidences were conducive to identifying the main biogeochemical processes occurring in the riverbed. The findings indicated that riparian groundwater exploitation alters the natural groundwater flow field, while fine sand deposition and microbial adsorption can reduce river recharge to aquifers by diminishing riverbed hydraulic conductivity. Shallow sediments within 1 m depth mainly involve NO3- reduction and E. coli adsorption. Reductive dissolution of Mn dominates in the deeper sediments. Additionally, reductive dissolution of Fe and dissimilatory nitrate reduction to ammonium (DNRA) drive high Fe2+ and NH4+ concentrations in groundwater. The findings can improve the management of riparian groundwater and aid in the optimization of a plan for its exploitation.

Clinical assessment of a CMC/PEO gel to inhibit postoperative epidural adhesion formation after lumbar discectomy: a randomized, control study.

PURPOSE: To evaluate effectiveness of carboxymethylcellulose/polyethylene oxide (CMC/PEO) gel in improving clinical outcomes after the first-time lumbar discectomy. METHOD: Ninety-three patients with herniated lumbar disc at L4-L5 or L5-S1 were enrolled and randomized into two groups: CMC/PEO gel treatment group and control group. All the patients underwent laminotomy and discectomy by posterior approach. The preoperative and postoperative Oswestry Disability Index (ODI) and Visual Analogue Scale (VAS) scores for lower-back pain and leg pain were analyzed and compared between two groups at 30- and 60-day time points. RESULTS: No patient presented with any clinically measurable adverse event during surgery. There were no significant differences between the treated group and the control group on the preoperative ODI and VAS scores. In general, the ODI and VAS scores decreased in both groups at all the time points. At the 30-day time point, the VAS scores for back pain and leg pain and the ODI scores in treatment group were lower by 9.9 % (P = 0.0302), 27.0 % (P = 0.0002) and 16.3 % (P = 0.0007) than those in control group. And at the 60-day time point, the ODI and VAS scores further decreased in both groups. The VAS scores for leg pain in treatment group were lower by 4.5 % than that in the control group (P = 0.0149). However, no significant difference was detected between two groups on the ODI and VAS scores for back pain. CONCLUSIONS: The results demonstrated that CMC/PEO gel is effective in reducing posterior dural adhesions in the spine with no apparent safety issues. It can improve patients' postoperative clinical outcome.

[A feasibility research of minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) using hybrid internal fixation for recurrent lumbar disc herniation].

OBJECTIVE: To investigate the feasibility of minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) using hybrid internal fixation of pedicle screws and a translaminar facet screw for recurrent lumbar disc herniation. METHODS: From January 2010 to December 2011, 16 recurrent lumbar disc herniation patients, 10 male and 6 female patients with an average age of 45 years (35-68 years) were treated with unilateral incision MIS-TLIF through working channel. After decompression, interbody fusion and fixation using unilateral pedicle screws, a translaminar facet screw was inserted from the same incision through spinous process and laminar to the other side facet joint. The results of perioperative parameters, radiographic images and clinical outcomes were assessed. The repeated measure analysis of variance was applied in the scores of visual analogue scale (VAS) and Oswestry disablity index (ODI). RESULTS: All patients MIS-TLIF were accomplished under working channel including decompression, interbody fusion and hybrid fixation without any neural complication. The average operative time was (148 ± 75) minutes, the average operative blood loss was (186 ± 226) ml, the average postoperative ambulation time was (32 ± 15) hours, and the average hospitalization time was (6 ± 4) days. The average length of incision was (29 ± 4) mm, and the average length of translaminar facets screw was (52 ± 6) mm. The mean follow-up was 16.5 months with a range of 12-24 months. The postoperative X-ray and CT images showed good position of the hybrid internal fixation, and all facets screws penetrate through facets joint. The significant improvement could be found in back pain VAS, leg pain VAS and ODI scores between preoperative 1 day and postoperative follow-up at all time-points (back pain VAS:F = 52.845, P = 0.000;leg pain VAS:F = 113.480, P = 0.000;ODI:F = 36.665, P = 0.000). CONCLUSION: Recurrent lumbar disc herniation could be treated with MIS-TLIF using hybrid fixation through unilateral incision, and the advantage including less invasion and quickly recovery.

Surgical treatment of osteoporotic thoracolumbar compressive fractures with open vertebral cement augmentation of expandable pedicle screw fixation: a biomechanical study and a 2-year follow-up of 20 patients.

BACKGROUND: The incidence of screw loosening increases significantly in elderly patients with severe osteoporosis. Open vertebral cement augmentation of expandable pedicle screw fixation may improve fixation strength in the osteoporotic vertebrae. MATERIALS AND METHODS: Twenty cadaveric vertebrae (L1-L5) were harvested from six osteoporotic lumbar spines. Axial pullout tests were performed to compare the maximum pullout strength (Fmax) of four methods: 1. Conventional pedicle screws (CPS), 2. Expandable pedicle screws (EPS), 3. Cement augmentation of CPS (cemented-CPS), 4. Cement augmentation of EPS (cemented-EPS). Thirty-six consecutive patients with single-vertebral osteoporotic compressive fractures received posterior decompression and spinal fusion with cemented-CPS (16 cases) or cemented-EPS (20 cases). Plain film and/or CT scan were conducted to evaluate the spinal fusion and fixation effectiveness. RESULTS: The Fmax and energy absorption of cemented-EPS were significantly greater than three control groups. The mean BMD in the severe osteoporosis group was significantly lower than that in the osteoporosis group (t = 2.04, P = 0.036). In the osteoporosis group, cemented-EPS improved the Fmax by 43% and 21% over CPS and cemented-CPS group. In the severe osteoporosis group, cemented-EPS increased the Fmax by 59%, 22%, and 26% over CPS, EPS, and cemented-CPS, respectively. The clinical results showed that all patients suffered from severe osteoporosis. Six months after operation, the JOA and VAS scores in cemented-EPS group improved from 11.4 ± 2.6 and 7.0 ± 1.4 mm to 24.9 ± 1.6 and 2.1 ± 1.3 mm, respectively. No screw loosening occurred in the cemented-EPS group and spinal fusion was achieved. In the cemented-CPS group, four screws loosened (4.2%) according to the radiolucency. Six months after operation, the JOA and VAS scores improved from 13.1 ± 1.9 and 7.6 ± 1.5 mm to 22.8 ± 2.2 and 2.5 ± 1.6 mm, respectively. No cement leaked into the spinal canal in both groups. CONCLUSIONS: Cemented-EPS could increase fixation strength biomechanically. It could reduce the risks of screw loosening in patients with severe osteoporosis, requiring instrumented arthrodesis.

Stress distribution on the screws in posterior lumbar fusion of isthmic spondylolisthesis with 2- or 3-vertebra fixation techniques: a biomechanical cadaveric study.

BACKGROUND: Two- or three-vertebra fixation techniques are both used in the treatment of spondylolisthesis. However, the number of spinal segments that should be implanted in spondylolisthesis reduction and fixation is still controversial, and there are no published reports on stress distribution on the screws with 2- or 3-vertebra fixation techniques. Understanding stress distribution in screws would be of potential great clinical importance and supply more biomechanical evidence in surgery. The aim of this study was to compare and quantitatively analyze the stress distribution on the screws in 2- or 3-vertebra fixation techniques in cadaveric models of spondylolisthesis. MATERIALS AND METHODS: Sixteen fresh specimens of human lumbar spines were used in this study. The spondylolisthesis model was generated by Panjabi method and fixed with the SINO universal spine system by 2- (group A) or 3-vertebra (group B) fixation technique. Rectangular electrical resistance strain gauges were fixed at upper and lower surface of the root of screws bilaterally. The samples were tested under flexion/extension, left/right lateral bending, and axial compression loading. Stress on the screws was measured by strain gauge monitor, respectively. RESULTS: Under the five different loading conditions, the stress could be compressive stress or tensile stress. Under the compression, flexion, and bending loading condition, the stress in reduction screws in group A is higher than in group B (P < 0.01). However, under the extension loading condition, stress of lower surface in reduction screws in group A is 49% lower than in group B. With regard to the anchor screws, under flexion and lateral bending conditions, stress in group A is lower than in group B (P < 0.05). Under compression and extension loading conditions, stress in group A is slightly higher than in group B, but no significant difference is detected. CONCLUSIONS: In most loading conditions, stress in reduction screws in 2-vertebra fixation technique was higher than in 3-vertebra fixation technique. The 3-vertebra fixation technique might effectively reduce stress on the reduction screws, and decrease the probability of fatigue fractures of the screws.

Accuracy and safety assessment of pedicle screw placement using the rapid prototyping technique in severe congenital scoliosis.

STUDY DESIGN: The application of rapid prototyping (RP) technique for improving accuracy of pedicle screw placement in congenital scoliosis is described in this study. OBJECTIVE: To compare the accuracy and safety of pedicle screw placement in congenital scoliosis using the RP technique versus the conventional fluoroscopy. SUMMARY OF BACKGROUND DATA: Maldeveloped vertebral components in congenital scoliosis leads to prolonged operation time and higher rate of screw misplacement. RP technique can enhance preoperative and perioperative planning. No data are available on the accuracy of pedicle screw fixation using the RP technique. METHODS: Sixty-two consecutive patients with hemivertebra had undergone posterior-only hemivertebra resection. Pedicle screws were implanted either by the conventional intraoperative fluoroscopy technique (C-arm group; n=28) or the RP technique (RP group; n=34). Accuracy of pedicle screw placement was compared by postoperative computed tomographic scan. RESULTS: Seventy of 677 inserted screws were found to be misplaced, showing an overall accuracy of 89.7% (90.8% in the thoracic spine and 87.4% in the lumbar spine). In the C-arm group, 86.1% (167 of 194) and 82.0% (82 of 100) of screws were accurately placed in the thoracic and lumbar spine, respectively. While in the RP group, the respective screw placement accuracies were 94.4% (238 of 252) and 91.6% (120 of 131). In the C-arm and the RP groups, 94.8% (279 of 294) and 97.9% (375 of 383) of the screws were within the safety zone, respectively. Compared with the fluoroscopy method, the RP-assisted technique showed a shorter operation time and higher scoliosis correction rate. No neurovascular-related complication was observed with this technique during the study. CONCLUSION: The application of RP technique in congenital scoliosis can reduce the operation time, the risk of screw misplacement and its consequent complications. The use of RP technique in congenital scoliosis is safe and efficacious.

Sustained-release rhBMP-2 increased bone mass and bone strength in an ovine model of postmenopausal osteoporosis.

OBJECTIVE: The purpose of this study was to analyze the local treatment effects of rhBMP-2 combined with fibrin sealant (FS) on bone mineral density, microarchitectural and mechanical properties in osteoporotic ovine spine. MATERIALS AND METHODS: Postmenopausal osteoporosis was induced in eight sheep through ovariectomy (OVX) and a low-calcium diet for a period of 12 months. According to the Latin square design, L3-L6 vertebrae were randomly assigned to four treatment groups: A (rhBMP-2/FS), B (rhBMP-2), C (FS) and D (blank control). All materials were injected into the assigned vertebra transpedicularly. All animals were euthanized 3 months after treatment. Bone mineral density (BMD), microarchitectural and mechanical properties were assessed. ANOVA analysis of variance was used to determine effects of rhBMP-2/FS (α = 0.05). RESULTS: The BMD in group A (rhBMP-2/FS) was 18.8, 30.4 and 27.9% higher than that in group B, C and D, respectively. Analysis of bone structure by micro-CT revealed higher trabecular bone volume (BV/TV), trabecular thickness (Tb.Th) and trabecular number (Tb.N) in the rhBMP-2/FS group (P < 0.01). In addition, vertebrae treated with rhBMP-2/FS exhibited higher yield stress, ultimate stress, energy absorption and bone modulus compared to the control groups. CONCLUSIONS: Local administration of rhBMP-2/FS showed a positive trend in improving BMD, microarchitectural parameters and mechanical strength of osteoporotic vertebra. Slow release of rhBMP-2 using FS appeared to be an effective method of protein delivery. The local treatment of osteoporosis in the spine can increase bone strength and reduce fracture risk quickly.

[A feasibility research of unilateral incision minimally invasive transforaminal lumbar interbody fusion using pedicle screws and a translaminar screw hybrid fixation].

OBJECTIVE: To investigate the feasibility and safety of unilateral incision hybrid fixation using pedicle screws and a translaminar screw in minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF). METHODS: From January to June 2010, 18 patients with single-level lumbar disc disease were treated with MIS-TLIF under METRx(TM) X-tube. After decompression and fixation using unilateral pedicle screws, a translaminar screw was inserted from the same incision to the other side. The results of perioperative parameters, radiographic images and clinical outcomes were assessed. RESULTS: All patients underwent MIS-TLIF were accomplished unilateral hybrid fixation without any neural complication. The average operative time was (107 ± 19) min, the average operative blood loss was (62 ± 21) ml, and the average postoperative ambulation time was (21 ± 5) h. The average length of translaminar facets screw was (52 ± 2) mm, and the postoperative images showed all screws penetrate through facets joint. During the follow-up the visual analogue scale and Oswestry disability index scores were significant improved compared with preoperative (F = 42.221 - 259.833, P < 0.01). CONCLUSIONS: Bilateral hybrid fixation could be completed through unilateral incision by pedicle screws and a translaminar screw in MIS-TLIF, and the advantage including less invasion, quickly recovery, short operative time, and saving fixation cost.

Experiments and simulation of co-migration of copper-resistant microorganisms and copper ions in saturated porous media.

Heavy metal (HV) pollutants may migrate to the groundwater environment through leaching, causing groundwater pollution. Compared with surface water pollution, groundwater pollution is complex and hidden. Existing methods for treating HV pollution in the vadose zone have had limited application owing to various problems. In recent years, microorganisms have been used in the field of pollution control and remediation owing to their outstanding adsorption and degradation properties and low cost, but their environmental safety and behavior in porous media are still poorly understood. This study aimed to investigate the migration behavior and mechanisms of copper ions in saturated porous media under the action of copper-resistant microorganisms and to establish a corresponding numerical model to simulate the results. The key parameters of adsorption and migration were determined through batch adsorption and soil column experiments. A one-dimensional soil column was used to conduct a co-migration experiment using copper-resistant microorganisms and Cu2+ in water-saturated quartz sand, and a co-migration mathematical model was constructed. It was found that the existence of microorganisms had an inhibitory effect on the migration of Cu2+ in quartz sand, and Cu2+ promoted the migration of microorganisms, reduced their adsorption, and increased their concentration in the column experiment effluent. The selected solute transport mathematical model had a good fitting effect on the breakthrough curves of copper ion and copper-resistant microorganisms during their co-migration. The results can provide parameters and a theoretical basis for the risk assessment and prevention of HV pollution in the saturated zone or aquifers.

Application of an expandable pedicle screw in the severe osteoporotic spine: a preliminary study.

PURPOSE: To investigate the clinical abstract and radiographic outcome of multi-axial expandable pedicle screws (MEPS) in patients with osteoporosis. METHODS: One hundred and twenty-five consecutive patients received MEPS from the UPASS spinal fixation system to obtain thoracolumbar or lumbosacral stabilization. All patients underwent bone mineral density (BMD) scans. The indications for use of the MEPS were spinal diseases with severe osteoporosis (degenerative diseases 46 cases, compression fractures 28 cases, lumbar tuberculosis 27 cases and revision spine surgery 24 cases). The pre-operative and three months post-operative functional evaluations were graded with JOA and VAS scoring system. One week, six months and 12 months after surgery, plain film and three-dimensional CT scans were obtained to evaluate the spinal fusion and fixation effectiveness of MEPS. RESULTS: The mean follow-up period was 18 months (ranged from 6 to 33 months). All patients suffered from severely osteoporosis with a decrease of 25.3% in BMD. The pre-operative JOA and VAS scores were 11.3±3.0 and 6.7±1.8 mm, respectively. Three months after operation, the JOA and VAS scores were 25.2±2.0 and 2.3±1.7 mm. The recovery rate was 78.1±11.5％ and the clinical results were satisfying. There were no instances of screw loosening or pullout of the MEPS and the screw-bone interface was excellent. The radiographic results showed that bone healing, both around the screws and inter-vertebral, was achieved. CONCLUSION: In osteoporosis spine surgery, excellent bone-screw interface and fixation strength can be achieved by using MEPS. MEPS are a novel approach to increase the pedicle screw fixation in osteoporotic and revision spine surgeries.

Water quality attribution and simulation of non-point source pollution load flux in the Hulan River basin.

Surface water is the main source of irrigation and drinking water for rural communities by the Hulan River basin, an important grain-producing region in northeastern China. Understanding the spatial and temporal distribution of water quality and its driving forces is critical for sustainable development and the protection of water resources in the basin. Following sample collection and testing, the spatial distribution and driving forces of water quality were investigated using cluster analysis, hydrochemical feature partitioning, and Gibbs diagrams. The results demonstrated that the surface waters of the Hulan River Basin tend to be medium-weakly alkaline with a low degree of mineralization and water-rock interaction. Changes in topography and land use, confluence, application of pesticides and fertilizers, and the development of tourism were found to be important driving forces affecting the water quality of the basin. Non-point source pollution load fluxes of nitrogen (N) and phosphorus (P) were simulated using the Soil Water and Assessment Tool. The simulation demonstrated that the non-point source pollution loading is low upstream and increases downstream. The distributions of N and P loading varied throughout the basin. The findings of this study provide information regarding the spatial distribution of water quality in the region and present a scientific basis for future pollution control.

[Modified posterior closing wedge osteotomy in patients of posttraumatic thoracic lumbar kyphosis].

OBJECTIVE: To evaluate the outcome of posterior trans-pedicle + disc osteotomy in patients with post-traumatic thoracolumbar kyphosis. METHODS: Between June 2000 and June 2003, 26 adult patients, 16 male and 10 female, average 30.6 years old (21 - 42 y), of post-traumatic thoracolumbar kyphosis were corrected by means of single posterior trans-pedicle + disc osteotomy technique. Operation time, blood loss, and surgical complication were counted. Back pain Visual Analog Scale (VAS) Oswestry score and Frankel neurological grade were used to for clinical evaluation. All the radiographic and clinical data were requested at 3 time points (before operation, directly postoperatively, and at final follow-up). RESULTS: No severe complications were found in this group. Local kyphosis (T(10)-L(2) Cobb angle) was corrected from average 22.3 degrees +/- 3.5 degrees to 2.2 degrees +/- 2.1 degrees (corrective rate 90.1%). Intraoperative average blood loss was (680.0 +/- 31.5) ml and average operational time was (186.0 +/- 22.8) min. All the patients finished at least 3 - 5 years follow-up, Neural improvement achieved in this group (before operation Frankel D 12 cases, Frankel C 6 cases and Frankel B2 cases; 3 years postoperation Frankel E 14 cases, Frankel D 2 cases Frankel C1 case and Frankel B 1 case), postoperative back pain was reduced from preoperative 8.6 +/- 1.3 to 2.2 +/- 0.5 in VAS and Oswestry score improved from (62.5 +/- 8.6)% to (16.2 +/- 4.3)% at last follow up. CONCLUSION: Single posterior trans-pedicle + disc osteotomy technique is suitable to thoracolumbar post-traumatic kyphosis.