Direct Internal Fixation for Unstable Atlas Fractures

Purpose@#To investigate the radiologic and clinical outcomes of direct internal fixation for unstable atlas fractures. @*Materials and Methods@#This retrospective study included 12 patients with unstable atlas fractures surgically treated using C1 lateral mass screws, rods, and transverse connector constructs. Nine lateral mass fractures with transverse atlantal ligament (TAL) avulsion injury and three 4-part fractures with TAL injury (two avulsion injuries, one TAL substance tear) were treated. Radiologic outcomes included the anterior atlantodental interval (AADI) in flexion and extension cervical spine lateral radiographs at 6 months and 1 year after treatment. CT was also performed to visualize bony healing of the atlas at 6 months and 1 year. Visual Analog Scale (VAS) scores for neck pain, Neck Disability Index (NDI) values, and cervical range of motion (flexion, extension, and rotation) were recorded at 6 months after surgery. @*Results@#The mean postoperative extension and flexion AADIs were 3.79±1.56 (mean±SD) and 3.13±1.01 mm, respectively. Then mean AADI was 3.42±1.34 and 3.33±1.24 mm at 6 months and 1 year after surgery, respectively. At 1 year after surgery, 11 patients showed bony healing of the atlas on CT images. Only one patient underwent revision surgery 8 months after primary surgery due to nonunion and instability findings. The mean VAS score for neck pain was 0.92±0.99, and the mean NDI value was 8.08±5.70. @*Conclusion@#C1 motion-preserving direct internal fixation technique results in good reduction and stabilization of unstable atlas fractures. This technique allows for the preservation of craniocervical and atlantoaxial motion.

Hypoxia Regulates the Extracellular Matrix via Mitogen-Activated Protein Kinases Pathway in Cells Retrieved from the Human Intervertebral Disc

Purpose@#The present study aimed to identify the physiological characteristics of cells by investigating the change in gene expression and protein levels during extracellular matrix (ECM) synthesis in the intervertebral disc (IVD) under hypoxic conditions. @*Materials and Methods@#To test the effect of oxygen on cell growth and ECM synthesis of chondrocyte-like cells, the cells from IVD were separated and cultured in two hypoxia-mimicking systems: chemical hypoxic conditions using deferoxamine (DFO), and physiological hypoxic conditions using a hypoxic chamber for 7 days. Chondrocyte like cells cultured without DFO and under the normal oxygen concentration (21% O2 and 5% CO2, 37°C) served as the controls. @*Results@#Chondrocyte-like cells cultured in the presence of 6% oxygen demonstrated a 100% increase in cellular proliferation compared to the control. The cells treated with chemical hypoxic conditions demonstrated a dose-dependent increase in the mRNA expression of glucose transporter-1, GAPDH, aggrecan, and type II collagen on Day 1. When treated with 100 μM DFO, the cells showed a 50% increase in the levels of proteoglycan protein on Day 7. The cells treated with chemical hypoxic condition demonstrated increase in sulfated glycosaminoglycan (GAG) protein levels on Day 7. Moreover, the cells cultured in the presence of 6% oxygen showed a 120% increase in sulfated GAG levels on Day 7. @*Conclusion@#The oxygen concentration had an important role in the viability, proliferation, and maturation of chondrocyte-like cells in IVD. In addition, chondrocyte-like cells are sensitive to the concentration of oxygen.

Hypoxia Regulates the Extracellular Matrix via Mitogen-Activated Protein Kinases Pathway in Cells Retrieved from the Human Intervertebral Disc

Purpose@#The present study aimed to identify the physiological characteristics of cells by investigating the change in gene expression and protein levels during extracellular matrix (ECM) synthesis in the intervertebral disc (IVD) under hypoxic conditions. @*Materials and Methods@#To test the effect of oxygen on cell growth and ECM synthesis of chondrocyte-like cells, the cells from IVD were separated and cultured in two hypoxia-mimicking systems: chemical hypoxic conditions using deferoxamine (DFO), and physiological hypoxic conditions using a hypoxic chamber for 7 days. Chondrocyte like cells cultured without DFO and under the normal oxygen concentration (21% O2 and 5% CO2, 37°C) served as the controls. @*Results@#Chondrocyte-like cells cultured in the presence of 6% oxygen demonstrated a 100% increase in cellular proliferation compared to the control. The cells treated with chemical hypoxic conditions demonstrated a dose-dependent increase in the mRNA expression of glucose transporter-1, GAPDH, aggrecan, and type II collagen on Day 1. When treated with 100 μM DFO, the cells showed a 50% increase in the levels of proteoglycan protein on Day 7. The cells treated with chemical hypoxic condition demonstrated increase in sulfated glycosaminoglycan (GAG) protein levels on Day 7. Moreover, the cells cultured in the presence of 6% oxygen showed a 120% increase in sulfated GAG levels on Day 7. @*Conclusion@#The oxygen concentration had an important role in the viability, proliferation, and maturation of chondrocyte-like cells in IVD. In addition, chondrocyte-like cells are sensitive to the concentration of oxygen.

Prevalence of Gastrointestinal and Cardiovascular Risk in Patients with Degenerative Lumbar Spinal Disease

Background@#Limited information is available about the proportion of patients with degenerative lumbar spinal disease (DLSD) who have gastrointestinal (GI) and cardiovascular (CV) risk factors. Many DLSD patients are prescribed nonsteroidal anti-inflammatory drugs (NSAIDs) that are known to carry risks to the GI and CV systems by increasing GI bleeding and thromboembolic events.This study aimed to measure the prevalence of GI and CV risk in patients with DLSD and to ascertain whether the prescription of NSAIDs is in line with current guidelines. @*Methods@#This study included 153 patients with symptomatic DLSD who were planning to undergo lumbar spinal surgery. The GI profile was checked using the GI Standardized Calculator of Risk for Event system and CV risk was evaluated using the presence of metabolic syndrome. The conformity of the prescription of NSAIDs was investigated according to the recommendations in current guidelines. @*Results@#More than half of the patients (59.5%) had high or very high GI risk, and 66% of the patients were diagnosed with metabolic syndrome, which corresponds with CV risk. The rate of simultaneous GI and CV risk was 40.5% (n = 62 / 153; gastrointestinal Standardized Calculator of Risk for Event, > high and metabolic syndrome, yes). The actual prescription of NSAIDs was not in accordance with current guidelines. @*Conclusions@#Two out of 3 patients had GI or CV risk factors, and approximately 40% of patients had both. Detailed assessment of GI and CV risk in patients with DLSD by using effective evaluation tools is mandatory for optimal medical treatment.

Lumbar Spinal Stenosis: Pathophysiology and Treatment Principle: A Narrative Review

Patients with lumbar spinal stenosis may exhibit symptoms such as back pain, radiating pain, and neurogenic claudication. Although long-term outcome of treatments manifests similar results for both nonsurgical and surgical treatments, positive effects such as short-term improvement in symptoms and decreased fall risk may be expected with surgery. Surgical treatment is basically decompression, and a combination of treatments can be added depending on the degree of decompression and the accompanying instability. Recently, minimally invasive surgery has been found to result in excellent outcomes in the treatment of lumbar spinal stenosis. Therefore, better treatment effects can be anticipated with an approach aimed at understanding the overall pathophysiology and treatment methods of lumbar spinal stenosis.

Results of Magnetically Controlled Growing Rods for Early Onset Scoliosis / 대한정형외과학회잡지

PURPOSE: To evaluate the first results of surgical treatment using newly developed magnetically controlled growing rods (MCGR) for early onset scoliosis (EOS). MATERIALS AND METHODS: From January 2013 to January 2017, 5 patients, who underwent surgical treatment with MCGR for EOS and were followed for more than one year, were analyzed retrospectively. The demographic and radiology data, including age at surgery, diagnosis, number of lengthening, Cobb angle, T1–S1 length, T1–T12 length, and complications, were analyzed. RESULTS: The mean age of the patients was 6.0±2.7 years old. The subjects were 3 males and 2 females: 2 with neuromuscular scoliosis, 1 with syndromic scoliosis, 1 with idiopathic scoliosis, and 1 with congenital scoliosis. The mean number of lengthening was 9.8±2.9 times and the follow-up was 21.6±5.7 months. The Cobb angle improved from 82.0°±28.5° to 48.3°±28.8° at the last follow-up. The T1–S1 length increased from 283.1±72.7 mm to 342.6±86.3 mm at the last follow-up. The T1–T12 length increased from 163.1±50.5 mm to 202.3±65.5 mm at the last follow-up. One screw loosening complication was encountered and there were no neurological complications. CONCLUSION: The treatment using MCGR for EOS is effective and useful.

Environmental Endocrine Disruptors and Neurological Disorders

We live in a world where daily exposure to environmental chemicals is inevitable. Many studies point to environmental chemicals a major cause of neurological diseases. Properly intervening in and managing the exposure requires up-to-date information about neurotoxic chemicals that may lead to neurological disorders. The recent literature on the neurotoxic effects of environmental chemicals was reviewed, including both animal and human studies. Parkinson's disease, Alzheimer's disease and autism are closely associated with environmental chemicals such as polychlorinated biphenys (PCBs), dioxins, polybrominated biphenyl ethers (PBDE), and perfluoroalkyls. There is strong evidence linking environmental chemical exposure to neurodevelopmental and neurodegenerative diseases. In particular, it is important to pay close attention to a high risk-age group where the window of exposure is critical to causing neurological disease.

Dual Growing Rod Treatment for Progressive Pediatric Spinal Deformity

STUDY DESIGN: Retrospective study. OBJECTIVES: To evaluate the outcomes of dual growing rod treatment over a follow-up period of at least 2 years in patients with progressive pediatric spinal deformity. SUMMARY OF LITERATURE REVIEW: The dual growing rod treatment is safe and effective in curve correction and maintenance in patients with progressive pediatric spinal deformity. MATERIALS AND METHODS: Between 2009 to 2017, 14 patients who underwent dual growing rod treatment were followed up for more than 2 years. We analyzed their demographic and radiologic data, including age at surgery, sex, diagnosis, instrumented levels, number of total operations, number of lengthening procedures, interval of lengthening, Cobb angle, thoracic kyphosis angle, lumbar lordosis angle, T1-S1 length, and complications. RESULTS: The mean age of the patients was 11.0±2.9 years old. There were 10 male and 4 female patients, including 8 cases of neuromuscular scoliosis, 3 cases of idiopathic scoliosis, 2 cases of spondyloepiphyseal dysplasia, and 1 case of congenital scoliosis. The mean follow-up period was 42.4±14.0 months. The total number of operations was 6.6±2.6. The average number of lengthening procedures was 4.3±2.3 at an interval of 6.9±2.1 months. The Cobb angle improved from 60.4°±27.9° to 33.5°±19.7° after the initial treatment and 29.1°±16.4° after the last follow-up or final fusion. The T1-S1 length increased from 328.2±57.5 mm to 388.0±64.9 mm after the initial treatment and 424.9±64.4 mm after the last follow-up or final spinal fusion. The average growth rate was 11.5 mm/year. Six patients experienced 11 complications, of which 4 were Implant-related, and 7 were Infections. CONCLUSIONS: The dual growing rod technique is an effective and relatively safe treatment in patients with progressive pediatric spinal deformity.

Effect of Sagittal Balance on Risk of Falling after Lateral Lumbar Interbody Fusion Surgery Combined with Posterior Surgery

PURPOSE: To demonstrate the impact of correcting sagittal balance (SB) on functional outcomes of surgical treatment for degenerative spinal disease and actual falls via utilization of new minimally invasive lumbar fusion techniques via a lateral approach. MATERIALS AND METHODS: From November 2011 to March 2015, we enrolled 56 patients who underwent minimally invasive lateral lumbar interbody fusion (LLIF) and matched 112 patients receiving decompression/postero-lateral fusion (PLF) surgery for lumbar spinal stenosis. According to SB status using C7-plumb line-distance (C7PL) and surgery type, patients were divided into three groups: SB PLF, sagittal imbalance (SI) PLF, and LLIF groups. We then compared their outcomes. RESULTS: The mean C7PL was 6.2±13.6 mm in the SB PLF group, 72.9±33.8 mm in the SI PLF group, and 74.8±38.2 mm in the LLIF group preoperatively. Postoperatively, C7PL in only the LLIF group improved significantly (p=0.000). Patients in the LLIF group showed greater improvement in fall-related functional test scores than the SI PLF group (p=0.007 for Alternate-Step test, p=0.032 for Sit-to-Stand test). The average number of postoperative falls was 0.4±0.7 in the SB PLF group, 1.1±1.4 in the SI PLF group, and 0.8±1.0 in the LLIF group (p=0.041). Oswestry Disability Index and the Euro-QoL 5 dimension visual analogue scale scores also showed greater improvements in the LLIF group than in the SI PLF group at postoperative 1 year (p=0.003, 0.016). CONCLUSION: Surgical correction of SI in patients with lumbar spinal stenosis using a combination of minimal invasive LLIF and posterior surgery achieved better surgical outcomes and a lower incidence of actual falls than PLF surgery.

Efficacy and Safety of Different Aceclofenac Treatments for Chronic Lower Back Pain: Prospective, Randomized, Single Center, Open-Label Clinical Trials

PURPOSE: Nonsteroidal anti-inflammatory drugs are a mainstay for medical treatment of chronic lower back pain (CLBP). Increased dose intervals for medication have been associated with increased patient adherence to prescriptions. The purpose of this clinical trial was to compare the efficacy and safety of a once daily dose of aceclofenac controlled release (CR) and a twice daily dose of aceclofenac for CLBP management. MATERIALS AND METHODS: A prospective, randomized, single center, open-label clinical trial was performed to compare the efficacy and safety of aceclofenac CR (200 mg once daily) to aceclofenac dose (100 mg twice daily). Fifty patients in each group were enrolled for the study. The primary end point was Visual Analogue Scale (VAS) change at baseline to that at 2 weeks after medication and safety profiles. Also, change in quality of life measured by EuroQoL 5D (EQ-5D) and Oswestry Disability Index (ODI) functional score for the lumbar spine were also assessed. RESULTS: Within groups at pre- and post-treatment, there were significant VAS reductions for aceclofenac CR and aceclofenac (p=0.028). EQ-5D increased significantly in both groups (p=0.037). ODI scores decreased significantly in both groups (p=0.012). However, there were no significant differences between aceclofenac CR and aceclofenac at pre- and post-treatment. Patients with aceclofenac CR showed significant increases in heartburn and indigestion and adverse gastrointestinal effects, compared to aceclofenac. CONCLUSION: In patients with CLBP, aceclofenac CR and aceclofenac demonstrated significant symptomatic pain relief, improvement in quality of life and functional scores. Aceclofenac CR slightly increased gastrointestinal adverse effects, such as heartburn and indigestion.

Pamidronate Down-regulates Tumor Necrosis Factor-alpha Induced Matrix Metalloproteinases Expression in Human Intervertebral Disc Cells

BACKGROUND: N-containing bisphosphonates (BPs), such as pamidronate and risedronate, can inhibit osteoclastic function and reduce osteoclast number by inducing apoptotic cell death in osteoclasts. The aim of this study is to demonstrate the effect of pamidronate, second generation nitrogen-containing BPs and to elucidate matrix metallo-proteinases (MMPs) mRNA expression under serum starvation and/or tumor necrosis factor alpha (TNF-α) stimulation on metabolism of intervertebral disc (IVD) cells in vitro. METHODS: Firstly, to test the effect of pamidronate on IVD cells in vitro, various concentrations (10⁻¹², 10⁻¹⁰, 10⁻⁸, and 10⁻⁶ M) of pamidronate were administered to IVD cells. Then DNA and proteoglycan synthesis were measured and messenger RNA (mRNA) expressions of type I collagen, type II collagen, and aggrecan were analyzed. Secondly, to elucidate the expression of MMPs mRNA in human IVD cells under the lower serum status, IVD cells were cultivated in full serum or 1% serum. Thirdly, to elucidate the expression of MMPs mRNA in IVD cells under the stimulation of 1% serum and TNF-α (10 ng/mL) In this study, IVD cells were cultivated in three dimensional alginate bead. RESULTS: Under the lower serum culture, IVD cells in alginate beads showed upregulation of MMP 2, 3, 9, 13 mRNA. The cells in lower serum and TNF-α also demonstrated upregulation of MMP-2, 3, 9, and 13 mRNA. The cells with various doses of pamidronate and lower serum and TNF-α were reveled partial down-regulation of MMPs. CONCLUSIONS: Pamidronate, N-containing second generation BPs, was safe in metabolism of IVD in vitro maintaining chondrogenic phenotype and matrix synthesis, and down-regulated TNF-α induced MMPs expression.

Surgical Outcome Predictor in Degenerative Lumbar Spinal Disease Based on Health Related Quality of Life Using Euro-Quality 5 Dimensions Analysis

PURPOSE: We aim to introduce the predictive value of a quantitatively described formula model in a multicenter prospective analysis using the EuroQol-5 dimensions (EQ-5D) health scale to anticipate postoperative improvement in patients with degenerative lumbar spine disease (DLSD). MATERIALS AND METHODS: Quality of life was evaluated in 376 patients from 17 tertiary hospitals before and after spinal decompression and fusion surgery. The five items of the EQ-5D, mobility (M), self-care (S), usual activities (A), pain/discomfort (P), and anxiety/depression (D), were checked as level 1, 2, or 3, with 3 being the worst. A minimal significant change in the calculated EQ-5D (cEQ-5D) was set as 0.05. Logistic regression analysis was performed to predict the highest successful outcome (cEQ-5D improvement after operation >0.05) with the given sets of 5 items of the EQ-5D. RESULTS: In the cEQ-5D analysis, among patients with a formula score of S+A+2×P+D≤8, 18/68 (27%) showed significant improvement in the cEQ-5D at 1 year postoperatively (p<0.05). However, in patients with a formula score of ≥9, 265/308 (86%) demonstrated significant improvements in the cEQ-5D at 1 year postoperatively (p<0.05). CONCLUSION: We suggest that S+A+2×P+D≥9 in the EQ-5D can quantitatively describe the better surgical outcome predictors for DLSD. With a definite DLSD lesion confirmed by an imaging study, patients who meet the formula scores of 9 or over and have refractory symptoms to non-operative treatment could be better surgical candidates resulting in satisfactory surgical outcomes of over 86%, than those who scored 8 or lower.

Preventive effects of imperatorin on perfluorohexanesulfonate-induced neuronal apoptosis via inhibition of intracellular calcium-mediated ERK pathway

Early life neuronal exposure to environmental toxicants has been suggested to be an important etiology of neurodegenerative disease development. Perfluorohexanesulfonate (PFHxS), one of the major perfluoroalkyl compounds, is widely distributed environmental contaminants. We have reported that PFHxS induces neuronal apoptosis via ERK-mediated pathway. Imperatorin is a furanocoumarin found in various edible plants and has a wide range of pharmacological effects including neuroprotection. In this study, the effects of imperatorin on PFHxS-induced neuronal apoptosis and the underlying mechanisms are examined using cerebellar granule cells (CGC). CGC were isolated from seven-day old rats and were grown in culture for seven days. Caspase-3 activity and TUNEL staining were used to determine neuronal apoptosis. PFHxS-induced apoptosis of CGC was significantly reduced by imperatorin and PD98059, an ERK pathway inhibitor. PFHxS induced a persistent increase in intracellular calcium, which was significantly blocked by imperatorin, NMDA receptor antagonist, MK801 and the L-type voltage-dependent calcium channel blockers, diltiazem and nifedipine. The activation of caspase-3 by PFHxS was also inhibited by MK801, diltiazem and nifedipine. PFHxS-increased ERK activation was inhibited by imperatorin, MK801, diltiazem and nifedipine. Taken together, imperatorin protects CGC against PFHxS-induced apoptosis via inhibition of NMDA receptor/intracellular calcium-mediated ERK pathway.

Mechanism of Ligamentum Flavum Hypertrophy / 대한정형외과연구학회지

Ligamentum flavum (LF) is yellowish ligament tissue connecting the lamina of adjacent vertebra. Degenerative changes in the spine cause the hypertrophy of LF and facet joint and disc bulging and herniation. These changes results in a narrowing of the spinal canal. Neural decompression surgery by removing the hypertrophied lamina, LF and disc pathologies has been considered as successful treatment method in lumbar spinal stenosis. This surgery has showed relatively satisfactory clinical results and has increased life-expectancy in elderly patients. However, issues about post spinal surgery syndrome and re-stenosis after the surgery also have been reported. Because LF is one of the main mechanisms of spinal stenosis, accurate understanding about pathologic mechanism on the LF hypertrophy may suggest alternative treatment methods such as medical treatment or less invasive treatment than surgical decompression can be considered. Hypertrophy of the ligamentum flavum is generated from increase of collagen synthesis, fibroblast proliferation, and fibrosis caused by 1) the expression of growth factors (TGF-beta1 etc.) stimulated by the repeated mechanical tension, 2) inflammatory cytokines from spinal facet joint structure and LF 3) delayed cell death, and 4) inflammatory cytokine from hypertrophied and degenerated LF itself. After the middle ages, gradual and partial inhibition of LF hypertrophy can be expected by administration NSAIDs or selective cyclo-oxygenase-2 inhibitors because these drugs may cause reduction of the increased cytokines. Also, relaxin can be another new treatment material for spinal stenosis by the mechanism of melting hypertrophied LF and reducing synthesis of collagen.

Relationship between Bone Mineral Density and Spinal Muscle Area in Magnetic Resonance Imaging

BACKGROUND: Bone mineral density (BMD) is known to have a positive correlation with lean body mass. Several studies have also reported the positive correlation between muscle power and BMD. From this point of view, we hypothesized BMD of lumbar spine to have a positive correlation with muscle mass. METHODS: Seventy-nine female patients aged between 60 and 75 years old and who underwent magnetic resonance imaging (MRI) and BMD studies were included. Muscle mass in spine MRI was defined by the sum of the average muscle area of three axial images for each disc level. Lumbosacral muscle is the sum of paraspinal muscle and psoas muscle. RESULTS: In correlation analysis, paraspinal muscle mass showed positive correlation with BMD of lumbar spine. Lumbosacral muscle mass showed positive correlation with BMD of trochanteric area of the femur. However, BMD of other area showed no significant correlation with muscle mass. CONCLUSIONS: Therefore, postmenopausal women older than 60 years with a well developed spine muscle mass, have a high BMD.

Marginal fit of anterior 3-unit fixed partial zirconia restorations using different CAD/CAM systems

PURPOSE: Few studies have investigated the marginal accuracy of 3-unit zirconia fixed partial dentures (FPDs) fabricated by computer-aided design/computer-aided manufacturing (CAD/CAM) system. The purpose of this study was to compare the marginal fit of zirconia FPDs made using two CAD/CAM systems with that of metal-ceramic FPDs. MATERIALS AND METHODS: Artificial resin maxillary central and lateral incisors were prepared for 3-unit FPDs and fixed in yellow stone. This model was duplicated to epoxy resin die. On the resin die, 15 three-unit FPDs were fabricated per group (45 in total): Group A, zirconia 3-unit FPDs made with the Everest system; Group B, zirconia 3-unit FPDs made with the Lava system; and Group C, metal-ceramic 3-unit FPDs. They were cemented to resin dies with resin cement. After removal of pontic, each retainer was separated and observed under a microscope (Presize 440C). Marginal gaps of experimental groups were analyzed using one-way ANOVA and Duncan test. RESULTS: Mean marginal gaps of 3-unit FPDs were 60.46 microm for the Everest group, 78.71 microm for the Lava group, and 81.32 microm for the metal-ceramic group. The Everest group demonstrated significantly smaller marginal gap than the Lava and the metal-ceramic groups (P.05). CONCLUSION: The marginal gaps of anterior 3-unit zirconia FPD differed according to CAD/CAM systems, but still fell within clinically acceptable ranges compared with conventional metal-ceramic restoration.

Comparative fracture strength analysis of Lava and Digident CAD/CAM zirconia ceramic crowns

PURPOSE: All-ceramic crowns are subject to fracture during function. To minimize this common clinical complication, zirconium oxide has been used as the framework for all-ceramic crowns. The aim of this study was to compare the fracture strengths of two computer-aided design/computer-aided manufacturing (CAD/CAM) zirconia crown systems: Lava and Digident. MATERIALS AND METHODS: Twenty Lava CAD/CAM zirconia crowns and twenty Digident CAD/CAM zirconia crowns were fabricated. A metal die was also duplicated from the original prepared tooth for fracture testing. A universal testing machine was used to determine the fracture strength of the crowns. RESULTS: The mean fracture strengths were as follows: 54.9 +/- 15.6 N for the Lava CAD/CAM zirconia crowns and 87.0 +/- 16.0 N for the Digident CAD/CAM zirconia crowns. The difference between the mean fracture strengths of the Lava and Digident crowns was statistically significant (P<.001). Lava CAD/CAM zirconia crowns showed a complete fracture of both the veneering porcelain and the core whereas the Digident CAD/CAM zirconia crowns showed fracture only of the veneering porcelain. CONCLUSION: The fracture strengths of CAD/CAM zirconia crowns differ depending on the compatibility of the core material and the veneering porcelain.

Neurologic Recovery According to the Spinal Fracture Patterns by Denis Classification

PURPOSE: Although Denis classification is considered as one of most clinically useful schemes for the evaluation of spinal fracture, there is little documentation on the relationship between fracture pattern and the neurologic recovery. The purpose is to evaluate the correlation between the fracture patterns according to Denis classification and neurologic recovery. MATERIALS AND METHODS: The 38 patients (26 men and 12 women) in this series had an average follow-up of 47.1 months, and they were all managed surgically. Denis classification had been used prospectively to determine the fracture morphology. Frankel Scale and American Spinal Injury Association Spinal Cord Injury Assessment Form [American Spinal Injury Association (ASIA) score] were obtained before surgery, after surgery and at the final follow-up. RESULTS: The common injuries making neurologic deterioration were burst fracture and fracture-dislocation. The degree of neurologic deficits seen first and at the final follow-up was more severe in fracture-dislocation than burst fracture. The neurologic recovery was not different between burst fracture and fracture-dislocation, assessed by Frankel grading and ASIA scoring system. The neurologic recovery evaluated by ASIA score was not different between the lumbar and thoracic spinal fracture. The neurologic recovery assessed by Frankel grade was greater in the lumbar spinal fractures in than the thoracic spinal fractures. CONCLUSION: The severity of initial and the final follow-up neurologic deficits were correlated with the fracture patterns according to Denis classification, but the neurologic recovery was not correlated.

Chlorination of ortho-position on Polychlorinated Biphenyls Increases Protein Kinase C Activity in Neuronal Cells

Polychlorinated biphenyls (PCBs) are persistent and bioaccumulative environmental pollutants. Recently, it is suggested that neurotoxic effects such as motor dysfunction and impairment in memory and learning have been associated with PCB exposure. However, structure relationship of PCB congeners with neurotoxic effects remains unknown. Since PKC signaling pathway is implicated in the modulation of motor behavior as well as learning and memory and the role of PKC are subspecies-specific, we attempted to study the effects of structurally distinct PCBs on the total PKC activity as well as subspecies of PKC in cerebellar granule cell culture model. Cells were exposed to 0, 25 and 50 microM of PCB-126, PCB-169, PCB-114, PCB-157, PCB-52 and PCB-4 for 15 min. Cells were subsequently analyzed by [3H] phorbol ester binding assay or immunoblotted against PKC-alpha and -epsilon monoclonal antibodies. While non-dioxin-like-PCB (PCB-52 and PCB-4) induced a translocation of PKC-alpha and -epsilon from cytosol to membrane fraction, dioxin-like PCBs (PCB-126, -169, -114, -157) had no effects. [3H] Phorbol ester binding assay also revealed structure-dependent increase similar to translocation of PKC isozymes. While PCB-4 induced translocation of PKC-alpha and -epsilon was inhibited by ROS inhibitor, the pattern of translocation was not affected in presence of AhR inhibitor. It is suggested that PCB-4-induced PKC activity may not be mediated via AhR-dependent pathway. Taken together, our findings suggest that chlorination of ortho-position in PCB may be a critical structural moiety associated with neurotoxic effects, which may be preferentially mediated via non-AhR-dependent pathway. Therefore, the present study may contribute to understanding the neurotoxic mechanism of PCBs as well as providing a basis for establishing a better neurotoxic assessment.

A study on the marginal fit of CAD/CAM 3-unit bridges / 대한치과보철학회지

PURPOSE: The purpose of this study was to assess the marginal fit of three-unit bridges produced using LAVA CAD/CAM (computer-aided design/computer-aided manufacturing) system and conventional PFG in vitro. MATERIALS AND METHODS: #11, 13 resin teeth were prepared on dentiform, then duplicated. Twenty resin models were fabricated, ten for PFG 3-unit bridges and ten for LAVA 3-unit bridges. Each bridge was cemented on the resin model. Marginal discrepancy was measured with stereoscopic microscope (Nikon DS-Fi 1, Nikon, Japan) at a magnification of x75. Independent t-test was done for the statistical analysis. RESULTS: The mean marginal discrepancy values and standard deviations of the PFG bridges was 97.1 +/- 18.7 microm for incisors, 76.6 +/- 21.8 microm for canines; that of the LAVA bridges was 90.4 +/- 26.7 microm for incisor, 110.2 +/- 30.2 microm for canines. The mean marginal discrepancy between PFG and LAVA for incisor did not show significant difference (P>.05). But for canine, the mean marginal discrepancy of PFG bridges was smaller than that of LAVA bridges (P<.05). CONCLUSION: The LAVA CAD/CAM 3-unit bridges and the PFG 3-unit bridges showed clinically acceptable marginal discrepancy.