Efficacy of the Dynesys Hybrid Surgery for Patients with Multi-Segmental Lumbar Spinal Stenosis

Objective

The efficacy of hybrid (Dynesys and fusion) surgery and the traditional transforaminal lumbar interbody fusion surgery was compared in patients with multi-segmental lumbar spinal stenosis.

Methods

A total of 68 patients with multi-segmental lumbar spinal stenosis subjected to surgery were recruited between January 2013 and October 2020 in the First Affiliated Hospital of Southern University of Science and Technology. The patients were divided into a hybrid group (N = 33) and a TLIF group (N = 35) by surgery. After surgery, follow-up was conducted for 12 months. Between the two groups, the following parameters were compared: general conditions, clinical symptom scores, imaging parameters, and early complications.

Results

A statistically significant difference in the duration of surgery was noted between the two groups. After 12 months of follow-up, the range of motion disappeared in the TLIF group, while 63.53% was preserved in the hybrid group with statistically significant differences. A statistically significant difference was identified in the Oswestry Disability Index one week after surgery. Nonetheless, no statistically significant differences were observed at the 12-month post-surgical follow-up. Pfirrmann grade showed a 3.03% upper adjacent segment degeneration rate in the hybrid group (1/33) at 12-month follow-up and 2.86% (1/35) in the TLIF group. Notably, no early complications (screw loosening and wound infection) were identified in the two groups.

Conclusion

The Dynesys hybrid surgery combined the advantages of two systems of dynamic stabilization and rigid fusion. Besides, hybrid surgery is potentially a novel approach for the treatment of multi-segmental lumbar spinal stenosis.

Circulating MicroRNA-19b Identified From Osteoporotic Vertebral Compression Fracture Patients Increases Bone Formation

Circulating microRNAs (miRNAs) play important roles in regulating gene expression and have been reported to be involved in various metabolic diseases, including osteoporosis. Although the transcriptional regulation of osteoblast differentiation has been well characterized, the role of circulating miRNAs in this process is poorly understood. Here we discovered that the level of circulating miR-19b was significantly lower in osteoporotic patients with vertebral compression fractures than that of healthy controls. The expression level of miR-19b was increased during osteoblastic differentiation of human mesenchymal stem cells (hMSCs) and MC3T3-E1 cells, and transfection with synthetic miR-19b could promote osteoblastic differentiation of hMSCs and MC3T3-E1 cells. PTEN (phosphatase and tensin homolog deleted from chromosome 10) was found to be directly repressed by miR-19b, with a concomitant increase in Runx2 expression and increased phosphorylation of AKT (protein kinase B, PKB). The expression level of circulating miR-19b in aged ovariectomized mice was significantly lower than in young mice. Moreover, the osteoporotic bone phenotype in aged ovariectomized mice was alleviated by the injection of chemically modified miR-19b (agomiR-19b). Taken together, our results show that circulating miR-19b plays an important role in enhancing osteoblastogenesis, possibly through regulation of the PTEN/pAKT/Runx2 pathway, and may be a useful therapeutic target in bone loss disorders, such as osteoporosis. © 2019 American Society for Bone and Mineral Research.

Multifunctional Nanoengineered Hydrogels Consisting of Black Phosphorus Nanosheets Upregulate Bone Formation

Tissue-engineered hydrogels have received extensive attention as their mechanical properties, chemical compositions, and biological signals can be dynamically modified for mimicking extracellular matrices (ECM). Herein, the synthesis of novel double network (DN) hydrogels with tunable mechanical properties using combinatorial screening methods is reported. Furthermore, nanoengineered (NE) hydrogels are constructed by addition of ultrathin 2D black phosphorus (BP) nanosheets to the DN hydrogels with multiple functions for mimicking the ECM microenvironment to induce tissue regeneration. Notably, it is found that the BP nanosheets exhibit intrinsic properties for induced CaP crystal particle formation and therefore improve the mineralization ability of NE hydrogels. Finally, in vitro and in vivo data demonstrate that the BP nanosheets, mineralized CaP crystal nanoparticles, and excellent mechanical properties provide a favorable ECM microenvironment to mediate greater osteogenic cell differentiation and bone regeneration. Consequently, the combination of bioactive chemical materials and excellent mechanical stimuli of NE hydrogels inspire novel engineering strategies for bone-tissue regeneration.

The effect of icariin on bone metabolism and its potential clinical application

Osteoporosis is a bone disease characterized by reduced bone mass, which leads to increased risk of bone fractures, and poses a significant risk to public health, especially in the elderly population. The traditional Chinese medicinal herb Epimedii has been utilized for centuries to treat bone fracture and bone loss. Icariin is a prenylated flavonol glycoside isolated from Epimedium herb, and has been shown to be the main bioactive component. This review provides a comprehensive survey of previous studies on icariin, including its structure and function, effect on bone metabolism, and potential for clinical application. These studies show that icariin promotes bone formation by stimulating osteogenic differentiation of BMSCs (bone marrow-derived mesenchymal stem cells), while inhibiting osteoclastogenic differentiation and the bone resorption activity of osteoclasts. Furthermore, icariin has been shown to be more potent than other flavonoid compounds in promoting osteogenic differentiation and maturation of osteoblasts. A 24-month randomized double-blind placebo-controlled clinical trial reported that icariin was effective in preventing postmenopausal osteoporosis with relatively low side effects. In conclusion, icariin may represent a class of flavonoids with bone-promoting activity, which could be used as potential treatment of postmenopausal osteoporosis.

A new variable for SRS plan quality evaluation based on normal tissue sparing: the effect of prescription isodose levels

OBJECTIVE

A new dosimetric variable, dose-dropping speed (DDS), was proposed and used to evaluate normal tissue sparing among stereotactic radiosurgery (SRS) plans with different prescription isodose lines.

METHODS

40 plans were generated for 8 intracranial SRS cases, prescribing to isodose levels (IDLs) ranging from 50% to 90% in 10% increments. Whilst maintaining similar coverage and conformity, plans at different IDLs were evaluated in terms of normal tissue sparing using the proposed DDS. The DDS was defined as the greater decay coefficient in a double exponential decay fit of the dose drop-off outside the planning target volume (PTV), which models the steep portion of the drop-off. Provided that the prescription dose covers the whole PTV, a greater DDS indicates better normal tissue sparing.

RESULTS

Among all plans, the DDS was found to be the lowest for the prescription at 90% IDL and the highest for the prescription at 60% or 70%. The beam profile slope change in the penumbra and its field size dependence were explored and given as the physical basis of the findings.

CONCLUSION

A variable was proposed for SRS plan quality evaluation. Using this measure, prescriptions at 60% and 70% IDLs were found to provide best normal tissue sparing.

ADVANCES IN KNOWLEDGE

A new variable was proposed based on which normal tissue sparing was quantitatively evaluated, comparing different prescription IDLs in SRS.

Intervention timing of strontium treatment on estrogen depletion-induced osteoporosis in rats: bone microstructure and mechanics

PURPOSE

To evaluate the effect of intervention timing of Sr treatment on trabecular bone microstructure and mechanics.

METHODS

Ninety female rats were randomly divided into three batches with three groups in each batch. Each group was divided according to the initiation timing of vehicle or strontium compound (SrC), which was at week 0 (early), 4 (mid-term) and 8 (late) after the ovariectomy, respectively. The treatment lasted for 12 weeks. The trabecular bone biomechanical properties, trabecular bone tissue mechanical properties, trabecular bone microstructure, and bone remodeling were analyzed with mechanical testing, nanoindentation, microCT, and histomorphometry, respectively. The osteoblast and osteoclast phenotypic genes were analyzed with real-time polymerase chain reaction (PCR).

RESULTS

Early and mid-term Sr treatment significantly increased biomechanical properties of trabecular bone, which was associated with increased microarchitecture parameters, increased bone formation parameters and up-regulation of osteoblast-related gene expression. Late Sr treatment failed to exert a beneficial effect on any of those parameters.

CONCLUSIONS

The beneficial effect of Sr was dependent on the intervention timing in ovariectomized rats.

Genetic diversity and relationships among different tomato varieties revealed by EST-SSR markers

The genetic diversity and relationship of 42 tomato varieties sourced from different geographic regions was examined with EST-SSR markers. The genetic diversity was between 0.18 and 0.77, with a mean of 0.49; the polymorphic information content ranged from 0.17 to 0.74, with a mean of 0.45. This indicates a fairly high degree of diversity among these tomato varieties. Based on the cluster analysis using unweighted pair-group method with arithmetic average (UPGMA), all the tomato varieties fell into 5 groups, with no obvious geographical distribution characteristics despite their diverse sources. The principal component analysis (PCA) supported the clustering result; however, relationships among varieties were more complex in the PCA scatterplot than in the UPGMA dendrogram. This information about the genetic relationships between these tomato lines helps distinguish these 42 varieties and will be useful for tomato variety breeding and selection. We confirm that the EST-SSR marker system is useful for studying genetic diversity among tomato varieties. The high degree of polymorphism and the large number of bands obtained per assay shows that SSR is the most informative marker system for tomato genotyping for purposes of rights/protection and for the tomato industry in general. It is recommended that these varieties be subjected to identification using an SSR-based manual cultivar identification diagram strategy or other easy-to-use and referable methods so as to provide a complete set of information concerning genetic relationships and a readily usable means of identifying these varieties.

The beneficial effect of icaritin on osteoporotic bone is dependent on the treatment initiation timing in adult ovariectomized rats

BACKGROUND

Epimedium-derived flavonoids (EFs) have a potential to treat established osteoporosis in postmenopausal women. However, one of the main disadvantages of the compound is the high volume and dosage during long-term administration period. Meanwhile, the beneficial effect of EFs on osteoporotic bone depends greatly on the intervention timing. Whether icaritin (ICT), an active molecular compound from EFs, can exert beneficial effect on osteoporotic bone and whether the beneficial effect is also dependent on the intervention timing remain unknown.

OBJECTIVE

The objective of this study was to evaluate the effect of the early and late ICT treatment on bone turnover markers, trabecular architecture, bone remodeling, biomechanics, colony formation of bone marrow stromal cells and osteoblast, adipocyte and osteoclast-related gene expression in adult ovariectomized rats.

METHODS

Eighty 9-month-old female rats (n=8/group) were sham-operated (Sham) or ovariectomized (OVX). The OVX rats were subjected to ICT treatment initiation at 1 month (early treatment) and 3 months (late treatment) post-operation, respectively. The vehicle-treated Sham and OVX rats starting at month 1 and month 3 post-operation served as the corresponding controls (Sham and OVX controls) for early and late ICT treatment, respectively. Those Sham and OVX rats sacrificed immediately before early and late ICT treatment served as the pretreatment baseline controls. Both ICT and vehicle treatments lasted for 2 months. The bone turnover markers, trabecular architecture, bone remodeling and bone biomechanical properties were analyzed with biochemistry, microCT, histomorphometry and mechanical testing, respectively. The population of bone marrow stromal cells (BMSCs) and osteoblasts were evaluated with colony formation assays, respectively. The expression levels of osteoblast, adipocyte and osteoclast-related genes in bone marrow were assessed by real-time polymerase chain reaction (PCR), respectively.

RESULTS

At the tissue level, early ICT treatment remarkably restored the trabecular bone mass, trabecular architecture and bone biomechanical properties towards pretreatment Sham levels, and significantly increased bone formation from pretreatment OVX level and markedly inhibited bone resorption towards pretreatment Sham level, whereas late ICT treatment failed to have any effect. At the cellular and molecular level, early ICT treatment significantly increased the number of osteoblastic colonies and the level of osteoblast-related gene expression compared to pretreatment OVX levels and remarkably decreased adipocyte and osteoclast-related gene expression towards pretreatment Sham levels. Late ICT treatment failed to have beneficial effect on any of these parameters.

CONCLUSION

ICT can exert anabolic and anti-resorptive effect on osteoporotic bone. The beneficial effect of ICT treatment is dependent on the intervention timing in established osteoporosis induced by estrogen depletion.

The cross-talk between osteoclasts and osteoblasts in response to strontium treatment: involvement of osteoprotegerin

BACKGROUND

The mechanism for the uncoupling effects of Sr on bone remains to be evaluated. Osteoblasts play important roles in osteoclastogenesis through regulating receptor activated nuclear factor kappa B (RANK) ligand (RANKL) and osteoprotegerin (OPG) expression. We hypothesize that OPG plays an important role in the cross-talk between osteoclasts and osteoblasts in response to Sr treatment.

MATERIALS AND METHODS

MC3T3E1 cells were treated with Sr chloride (0-3 mM) and conditioned media were collected at 24h after the treatment. The effect of conditioned media on osteoclastogenesis was evaluated by tartrate-resistant acid phosphatase (TRAP) staining and bone resorption pits analysis. OPG and RANKL mRNA expressions in osteoblastic cells and protein secretion in the conditioned media were analyzed with real-time PCR and ELISA assay, respectively. The role of OPG in Sr-mediated inhibition of osteoclastogenesis was further evaluated with anti-OPG antibody in pre-osteoclastic cells. The role of OPG in Sr-mediated uncoupling effects on osteoporotic bone was evaluated by an animal study. Ovariectomized rats were oral administrated with vehicle or Sr chloride for two months supplemented with anti-IgG antibody (control) or anti-OPG antibody. The effects of OPG neutralization after Sr treatment on bone metabolism were analyzed by microCT, bone histomorphometry and biochemical analysis.

RESULTS

The conditioned media derived from Sr-treated osteoblastic cells exerted a dose-dependent inhibitory effect on osteoclastic differentiation and resorptive activity in pre-osteoclastic cells. OPG mRNA expression and protein secretion in osteoblastic cells were significantly increased after Sr treatment. Neutralization with anti-OPG antibody abolished the inhibitory effect of conditioned media on RANKL-induced osteoclastogenesis. The uncoupling effects of Sr treatment on trabecular bone were evidenced by greater bone volume and trabecular number, greater osteoid surface and bone formation rate, while less osteoclast surface. These effects were attenuated by the OPG neutralization by anti-OPG antibody injection.

CONCLUSION

The evidences from the in vitro and in vivo studies suggested that OPG played an important role in the uncoupling effect of Sr on bone metabolism, possibly by acting as a cross-talk molecule between osteoclasts and osteoblasts in response to Sr treatment.

Antitumor Activity of Tiazofurin in Human Colon Carcinoma HT-29

Tiazofurin is effective in treating end-stage leukemic patients (Tricot et al., Cancer Res 49:3696-3701, 1989). In sensitive tumors, the active metabolite of tiazofurin, TAD, potently inhibits IMP dehydrogenase activity, resulting in reduced guanylate pools. To elucidate tiazofurin activity in human solid tumors, we examined its activity in human colon carcinoma HT-29. Tiazofurin exhibited an LC50 of 35 microM in cultured HT-29 cells. Incubation of HT-29 cells with 100 microM tiazofurin for 2 h resulted in TAD formation (9.3 nmol/g cells) and in a 64% decrease in GTP pools. For biochemical and chemotherapy studies, athymic nude mice were transplanted s.c. with HT-29 cells. Twenty-four days later, mice were injected i.p. with tiazofurin (500 mg/kg); 6 h later, tumors were removed and analyzed. These tumors formed 17 nmol/g of TAD with decreased GTP pools (56%). To study oncolytic activity, transplanted mice were treated 24 h later with tiazofurin (500 mg/kg, once a day for 10 days). To examine the effectiveness of tiazofurin in established tumors, the drug was administered to mice 14 days after tumor implantation (500 mg/kg, once a day for 5 days, course repeated 4 times with a 10-day rest). Both treatment schedules resulted in significant antitumor activity. This study illustrates the potential usefulness of tiazofurin in treating human colon carcinoma.

The Drosophila homolog of the human tumor suppressor gene BHD interacts with the JAK-STAT and Dpp signaling pathways in regulating male germline stem cell maintenance

Birt-Hogg-Dubé syndrome (BHD) is a rare, inherited genodermatosis characterized by hair follicle hamartomas, kidney tumors and spontaneous pneumothorax. The BHD locus was mapped to chromosome 17p11.2 by linkage analysis, and germline mutations in a novel gene (BHD) were identified in a panel of BHD families. Using RNA interference to decrease expression of the Drosophila BHD homolog (DBHD), we have demonstrated that DBHD is required for male germline stem cell (GSC) maintenance in the fly testis. Reduction of DBHD gene activity suppresses the GSC overproliferation phenotype associated with overexpression of either unpaired (upd) or decapentaplegic (dpp). Further genetic interaction experiments suggest that DBHD regulates GSC maintenance downstream or in parallel of the JAK/STAT and Dpp signal-transduction pathways. These findings suggest that the BHD protein may regulate tumorigenesis through modulating stem cells in human.

Dose volume histogram comparison between ADAC Pinnacle and Nomos Corvus systems for IMRT

This paper compares dose volume histograms (DVHs) generated by the ADAC Pinnacle and the Nomos Corvus planning systems. Seven prostate cases and seven head and neck cases were selected for review. Plans computed on both systems possessed exactly the same anatomical contours and IMRT segments. The Pinnacle system used the collapsed cone convolution superposition, while Corvus employed a finite size pencil beam (FSPB) convolution. Prostate DVH results demonstrated similar DVH curves from both systems. For each structure, the ratio of Pinnacle dose value divided by Corvus value was calculated. The high dose structures (which might contain tumour) had ratios close to unity, while the low dose structures (the critical organs) had ratios farther away from unity. Almost all ratios were less than unity, indicating a systematic difference that Pinnacle calculated doses were lower than Corvus ones. Head and neck data provided similar findings. A possible cause for this discrepancy could be the beam modelling. The difference in DVH parameters that we discovered between the two systems was about the same order of magnitude as the measurement-computation difference. When low dose is critical, such difference may affect the clinical planning decision.

[Recovery and evoked potential of nerve root under variable chronic injury]

OBJECTIVE

To study the recovery and mechanism of nerve root under variable chronic injury and to determine the alerting index of the evoked potential of the irreversible injury to the nerve root, so as to offer the evidence for selecting treatment methods, judging prognosis and grasping treatment juncture.

METHODS

Autogenous cancellous bones were planted into the right C7-8 and C8-T1 intervertebral foramens in 30 cats with weight 3-5 kg to make chronic injury models. The left side was for auto-contrast. By 24 weeks' observation and dynamic supervisory of evoked potential, the injury degrees were ascertained and classified into I to V degree groups. Then the operation of decompression was performed on every group. During the following 32 weeks, the evoked potential survey and pathological tissue examination were made every week to observe the function recovery of the injured roots.

RESULTS

The tissue form and function of the nerve roots with I and II degree injuries recovered well within 2 to 6 weeks. Those with II degree injury began to recover in the 4th week, and gradually recovered to normal 12 weeks later. In the group of IV degree injury, the recovery was slow. They could recover completely in 3 of 6 cats, partly in 2 and hardly recovered in 1. The function and tissue form of nerve roots with V degree injury could hardly recovered.

CONCLUSION

In the case that the compression has been removed before the nerve roots suffer II degree injury. The tissue form and function of the nerve roots will recovered satisfactorily, whereas they may suffer irreversibly injury by IV degree injury, and even can hardly recover by V degree injury. During the supervisory process of the recovery of the injured nerve roots, sensitive evoked potential is a sensitive sign of early recovery and motion evoked potential is a reliable sign of recovery extent.

Giant-cell tumour of bone. The long-term results of treatment by curettage and bone graft

Giant-cell tumour of bone (GCT) is a locally benign aggressive tumour. The use of adjuvant agents, such as phenol or liquid nitrogen has been recommended to destroy the remaining tumour cells after curettage, and filling of the defect with methylmethacrylate cement has been advocated. Between 1957 and 1992 we treated 92 patients with a GCT with 50% aqueous zinc chloride solution and bone grafting. Their mean age at the time of surgery was 31 years (15 to 59) and the mean follow-up was 11 years (5 to 31). Twelve (13%) had a local recurrence and one had a wound infection. Two developed degenerative changes around the knee. Eighty-six (93%) achieved good or excellent function. Three had moderate function, and three needed amputation. Our findings indicate that treatment with an aqueous solution of zinc chloride and reconstructive bone grafting after curettage gives good results.

Leaf sequencing techniques for MLC-based IMRT

The nonuniform fields required by intensity-modulation radiation therapy (IMRT) can be delivered using conventional multileaf collimators (MLC) as beam modulators. In MLC-based IMRT, the nonuniform field is initially converted into an intensity map represented as a matrix of beam intensities. The intensity map is then decomposed into a series of subfields or segments of uniform intensities. Although there are many ways of segmenting the beam intensity matrix, a resulting subfield is only deliverable if it satisfies the constraints imposed by the MLC. These constraints exist as a result of the design of the MLC. The simplest constraint of the MLC is that its pairs of leaves can only move in and out in one dimension. Additional constraints include collision of opposing leaves and the need to match the tongue-and-groove to reduce interleaf leakage. The practical aspect of MLC-based IMRT requires that an optimized algorithm decomposes the nonuniform field into the least number of segments and therefore reduces the delivery time. This paper examines the static use and the dynamic use of MLCs to perform MLC-based IMRT.