The time course of dysphagia following traumatic cervical spinal cord injury: a prospective cohort study.

STUDY DESIGN: Prospective cohort study. OBJECTIVES: To elucidate serial changes in dysphagia and elucidate the critical period for dysphagia following acute traumatic cervical spinal cord injury (CSCI). SETTING: Spinal Injuries Center, Fukuoka, Japan. METHODS: We prospectively examined individuals with acute traumatic CSCI admitted within 2 weeks after injury. Severity of dysphagia was evaluated using both the dysphagia severity scale (DSS) and functional oral intake scale (FOIS) at 2 weeks, 1 month, 2 months, and 3 months after injury. Condition of oral intake before injury was assessed by history taking. American Spinal Injury Association (ASIA) impairment scale grade and motor scores were also assessed at the same timepoints, and the correlation between dysphagia and paresis was analyzed. RESULTS: Sixty-five individuals with CSCI were assessed consecutively for 3 months after injury. Swallowing function, evaluated using both the DSS and FOIS, was significantly decreased at 2 weeks after injury, but significantly improved thereafter. Significant correlations between severity of dysphagia (DSS and FOIS scores) and motor scores were found at 2 weeks after injury (rs = 0.66 and 0.61; p < 0.001 and p < 0.001, respectively), indicating that individuals with lower motor scores had more severe swallowing dysfunction. CONCLUSIONS: Dysphagia occurred immediately after injury, but gradually improved over time. Individuals with more severe paralysis had significantly more severe dysphagia. Special attention for dysphagia should be paid to individuals with severe paralysis in acute phase.

How much time is necessary to confirm the diagnosis of permanent complete cervical spinal cord injury?

STUDY DESIGN: Retrospective chart audits. OBJECTIVE: To investigate the optimal timing at which permanent complete cervical spinal cord injury (CSCI) can be confirmed when evaluating paralysis caused by traumatic CSCI. SETTING: Department of Orthopedic Surgery, Spinal Injuries Center, Japan. METHODS: Two-hundred and three patients with CSCI that was classified with an American Spinal Injury Association (ASIA) Impairment Scale (AIS) grade A (AIS A) within 72 h of the initial diagnosis of traumatic CSCI were included in the present study. Neurological data from the time of the initial diagnosis to 1 year after the injury were extracted. The number of those with recovery from AIS A and changes of AIS in the recovery were examined. RESULTS: Thirty-five of 203 (17%) patients whose injuries were initially classified with an AIS A showed recovery from AIS A. Thirty-four of 35 (97%) patients showed recovery from AIS A within 8 weeks after injury. CONCLUSION: If CSCI patients with AIS A have not recovered by 8 weeks, the likelihood that they will recover from AIS A is marginal. However, this conversely means that we must consider the possibility that a patient with a traumatic CSCI classified with an AIS A may still show recovery from AIS A within the first 8 weeks after injury.

Progression of local kyphosis after conservative treatment for compressive cervical spine fracture with spinal cord injury.

INTRODUCTION: Compressive-flexion type cervical spine fracture is typically accompanied by apparent dislocation of the facet joints, undesirable cervical alignment, and devastating neurological dysfunction, which provides strong rationale for rendering prompt operative treatment. However, the validity of conservative treatment for compressive-flexion cervical spine injury in cases with preserved congruity of the facet joints has yet to be elucidated. The purpose of this study is to evaluate the long-term outcome of cervical alignment following conservative treatment for compressive-flexion cervical spine injury with preserved congruity of the facet joints. METHODS: A total of 662 patients who experienced spinal cord injury from 2007 to 2017 were included and underwent retrospective review in a single institute. Thirteen patients were identified as receiving conservative therapy following compressive-flexion cervical spine fractures with spinal cord injury. Clinical and radiological results were collected, including vertical fractures of the vertebral column, laminar fractures, progression of local kyphosis, and neurological status. The degree of the local cervical kyphosis was evaluated with two methods: the posterior tangent method and the endplate method. RESULTS: All 13 patients were male, and the mean age at the time of injury was 28.4 years. The mean follow-up period was 3 years. Although none of the patients presented neurological deterioration after the injury, the degree of local kyphosis was increased at the time of final follow-up compared to what was observed at the time of injury. Patient age at the time of injury and concurrent vertical fracture of vertebral body could have been influencing factors for the progression of the kyphosis. While laminar fracture affected the kyphosis at the time of injury, it was not a strong influencing factor of the overall progression of local kyphosis. CONCLUSIONS: The conservative option for the compressive-flexion cervical injury allowed us to treat without exacerbating neurological symptoms as long as the facet joints are preserved. However, in terms of cervical alignment, surgical stabilization may have been desirable for these patients. Notably, the younger patients and the patients with vertical fracture of the cervical vertebral column in this type of injury required closer observation to help prevent the progression of local kyphosis.

Sequential neurological improvements after conservative treatment in patients with complete motor paralysis caused by cervical spinal cord injury without bone and disc injury.

OBJECTIVE This study investigated neurological improvements after conservative treatment in patients with complete motor paralysis caused by acute cervical spinal cord injury (SCI) without bone and disc injury. METHODS This study was retrospective. The authors evaluated neurological outcomes after conservative treatment of 62 patients with complete motor paralysis caused by cervical SCI without bone and disc injury within 72 hours after trauma. The sequential changes in their American Spinal Injury Association Impairment Scale (AIS) grades were reviewed at follow-up 24-72 hours, 1 week, and 1, 3, and 6 months after treatment. RESULTS Of the 31 patients with a baseline AIS grade of A, 2 (6.5%) patients improved to grade B, 5 (16.1%) improved to grade C, and 2 (6.5%) improved to grade D by the 6-month follow-up. The 22 (71.0%) patients who remained at AIS grade A 1 month after injury showed no neurological improvement at the 6-month follow-up. Of the 31 patients with a baseline AIS grade of B, 12 (38.7%) patients showed at least a 1-grade improvement at the 1-month follow-up; 11 (35.5%) patients improved to grade C and 16 (51.6%) patients improved to grade D at the 6-month follow-up. CONCLUSIONS Even in patients with complete motor paralysis caused by cervical SCI without bone and disc injury within 72 hours after trauma, approximately 30% of the patients with an AIS grade of A and 85% of the patients with an AIS grade B improved neurologically after conservative treatment. It is very important to recognize the extent of neurological improvement possible with conservative treatment, even for severe complete motor paralysis.

A Safe Surgical Procedure for Old Distractive Flexion Injuries of the Subaxial Cervical Spine.

STUDY DESIGN: Retrospective review. PURPOSE: To describe a safe and effective surgical procedure for old distractive flexion (DF) injuries of the subaxial cervical spine. OVERVIEW OF LITERATURE: Surgical treatment is required in old cases when a progression of the kyphotic deformity and/or persistent neck pain and/or the appearance of new neurological symptoms are observed. Since surgical treatment is more complicated and dangerous in old cases than in acute distractive-flexion cases, the indications for surgery and the selection of the surgical procedure must be carefully conducted. METHODS: To identify a safe and effective surgical procedure, the procedure selected, reason(s) for its selection, and associated neurological complications were investigated in 13 patients with old cervical DF injuries. RESULTS: No neurological complications were observed in nine patients (DF stage 2 or 3) who underwent the anterior-posterior-anterior (A-P-A) method and two patients (DF stage 1) who underwent the posterior method. It was initially planned that two patients (DF stage 2) who underwent the P-A method would be treated using the Posterior method alone; however, anterior discectomy was added to the procedure after the development of a severe spinal cord disorder. CONCLUSIONS: The A-P-A method (anterior discectomy, posterior release and/or partial facetectomy, reduction and instrumentation, anterior bone grafting) is considered to be a suitable surgical procedure for old cervical DF injuries.

Can the acute magnetic resonance imaging features reflect neurologic prognosis in patients with cervical spinal cord injury?

BACKGROUND CONTEXT: Several prognostic studies looked for an association between the degree of spinal cord injury (SCI), as depicted by primary magnetic resonance imaging (MRI) within 72 hours of injury, and neurologic outcome. It was not clearly demonstrated whether the MRI at any time correlates with neurologic prognosis. PURPOSE: The purpose of the present study was to investigate the relationship between acute MRI features and neurologic prognosis, especially walking ability of patients with cervical spinal cord injury (CSCI). Moreover, at any point, MRI was clearly correlated with the patient's prognosis. STUDY DESIGN: Retrospective image study. PATIENT SAMPLE: From January 2010 to October 2015, 102 patients with CSCI were treated in our hospital. Patients who were admitted to our hospital within 3 days after injury were included in this study. The diagnosis was 78 patients for CSCI with no or minor bony injury and 24 patients for CSCI with fracture or dislocation. A total of 88 men and 14 women were recruited, and the mean patient age was 62.6 years (range, 16-86 years). Paralysis at the time of admission was graded as A in 32, B in 15, C in 42, and D in 13 patients on the basis of the American Spinal Injury Association (ASIA) impairment scale. Patients with CSCI with fracture or dislocation were treated with fixation surgery and those with CSCI with no or minor bony injury were treated conservatively. Patients were followed up for an average of 168 days (range, 25-496 days). OUTCOME MEASURES: Neurologic evaluation was performed using the ASIA motor score and the modified Frankel grade at the time of admission and discharge. METHODS: Magnetic resonance imaging was performed for all patients at admission. Using the MRI sagittal images, we measured the vertical diameter of intramedullary high-intensity changed area with T2-weighted images at the injured segment. We studied separately the patients divided into two groups: 0-1 day admission after injury, and 2-3 days admission after injury. We evaluated the relationship between the vertical diameter of T2 high-intensity changed area in MR images and neurologic outcome in these two groups. This study does not contain any conflict of interest. RESULTS: In the group admitted at 0-1 day after injury, there was a relationship between the vertical diameter of T2 high-intensity area in MR image and the ASIA motor score at admission and at discharge, but correlation coefficient was low (0.3766 at admission and 0.4239 at discharge). On the other hand, in the group admitted at 2-3 days after injury, there was a significant relationship between the vertical diameter of T2 high-intensity area in MR image and the ASIA motor score at admission and at discharge, and correlation coefficient was very high (0.6840 at admission and 0.5293 at discharge). In the group admitted at 2-3 days after injury, a total of 17 patients (68%) recovered to walk with or without a cane. Receiver operating characteristic (ROC) curve analysis demonstrated that the optimal vertical diameter of T2 high-intensity area cutoffvalue for patients who were able to walk at discharge was 45.8 mm. If the vertical diameter of T2 high-intensity area cutoff value was 45 mm, there was a significant positive correlation with being able to walk at discharge (p<.0001). CONCLUSIONS: From our study, 2-3 days after injury, a significant relationship was observed between the vertical diameter of T2 high-intensity area and the neurologic prognosis at discharge. Zero to 1 day after injury, the relationship between the vertical diameter of T2 high-intensity area and the neurologic prognosis at discharge was weak. Neurologic prognosis is more correlated with MRI after 2-3 days after the injury. If the vertical diameter of T2 high-intensity area was <45 mm, the patients were able to walk with or without a cane at discharge. T2 high-intensity changed area can reflect the neurologic prognosis in patients with CSCI.

Clinical Influence of Cervical Spinal Canal Stenosis on Neurological Outcome after Traumatic Cervical Spinal Cord Injury without Major Fracture or Dislocation.

STUDY DESIGN: Retrospective case series. PURPOSE: To clarify the influence of cervical spinal canal stenosis (CSCS) on neurological functional recovery after traumatic cervical spinal cord injury (CSCI) without major fracture or dislocation. OVERVIEW OF LITERATURE: The biomechanical etiology of traumatic CSCI remains under discussion and its relationship with CSCS is one of the most controversial issues in the clinical management of traumatic CSCI. METHODS: To obtain a relatively uniform background, patients non-surgically treated for an acute C3-4 level CSCI without major fracture or dislocation were selected. We analyzed 58 subjects with traumatic CSCI using T2-weighted mid-sagittal magnetic resonance imaging. The sagittal diameter of the cerebrospinal fluid (CSF) column, degree of canal stenosis, and neurologic outcomes in motor function, including improvement rate, were assessed. RESULTS: There were no significant relationships between sagittal diameter of the CSF column at the C3-4 segment and their American Spinal Injury Association motor scores at both admission and discharge. Moreover, no significant relationships were observed between the sagittal diameter of the CSF column at the C3-4 segment and their neurological recovery during the following period. CONCLUSIONS: No relationships between pre-existing CSCS and neurological outcomes were evident after traumatic CSCI. These results suggest that decompression surgery might not be recommended for traumatic CSCI without major fracture or dislocation despite pre-existing CSCS.

TRAIL-R2 Superoligomerization Induced by Human Monoclonal Agonistic Antibody KMTR2.

The fully human monoclonal antibody KMTR2 acts as a strong direct agonist for tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) receptor 2 (TRAIL-R2), which is capable of inducing apoptotic cell death without cross-linking. To investigate the mechanism of direct agonistic activity induced by KMTR2, the crystal structure of the extracellular region of TRAIL-R2 and a Fab fragment derived from KMTR2 (KMTR2-Fab) was determined to 2.1 Å resolution. Two KMTR2-Fabs assembled with the complementarity-determining region 2 of the light chain via two-fold crystallographic symmetry, suggesting that the KMTR2-Fab assembly tended to enhance TRAIL-R2 oligomerization. A single mutation at Asn53 to Arg located at the two-fold interface in the KMTR2 resulted in a loss of its apoptotic activity, although it retained its antigen-binding activity. These results indicate that the strong agonistic activity, such as apoptotic signaling and tumor regression, induced by KMTR2 is attributed to TRAIL-R2 superoligomerization induced by the interdimerization of KMTR2.

Effect of preservation of the C-6 spinous process and its paraspinal muscular attachment on the prevention of postoperative axial neck pain in C3-6 laminoplasty.

OBJECT: Axial neck pain after C3-6 laminoplasty has been reported to be significantly lesser than that after C3-7 laminoplasty because of the preservation of the C-7 spinous process and the attachment of nuchal muscles such as the trapezius and rhomboideus minor, which are connected to the scapula. The C-6 spinous process is the second longest spinous process after that of C-7, and it serves as an attachment point for these muscles. The effect of preserving the C-6 spinous process and its muscular attachment, in addition to preservation of the C-7 spinous process, on the prevention of axial neck pain is not well understood. The purpose of the current study was to clarify whether preservation of the paraspinal muscles of the C-6 spinous process reduces postoperative axial neck pain compared to that after using nonpreservation techniques. METHODS: The authors studied 60 patients who underwent C3-6 double-door laminoplasty for the treatment of cervical spondylotic myelopathy or cervical ossification of the posterior longitudinal ligament; the minimum follow-up period was 1 year. Twenty-five patients underwent a C-6 paraspinal muscle preservation technique, and 35 underwent a C-6 nonpreservation technique. A visual analog scale (VAS) and VAS grading (Grades I-IV) were used to assess axial neck pain 1-3 months after surgery and at the final follow-up examination. Axial neck pain was classified as being 1 of 5 types, and its location was divided into 5 areas. The potential correlation between the C-6/C-7 spinous process length ratio and axial neck pain was examined. RESULTS: The mean VAS scores (± SD) for axial neck pain were comparable between the C6-preservation group and the C6-nonpreservation group in both the early and late postoperative stages (4.1 ± 3.1 vs 4.0 ± 3.2 and 3.8 ± 2.9 vs 3.6 ± 3.0, respectively). The distribution of VAS grades was comparable in the 2 groups in both postoperative stages. Stiffness was the most prevalent complaint in both groups (64.0% and 54.5%, respectively), and the suprascapular region was the most common site in both groups (60.0% and 57.1%, respectively). The types and locations of axial neck pain were also similar between the groups. The C-6/C-7 spinous process length ratios were similar in the groups, and they did not correlate with axial neck pain. The reductions of range of motion and changes in sagittal alignment after surgery were also similar. CONCLUSIONS: The C-6 paraspinal muscle preservation technique was not superior to the C6-nonpreservation technique for preventing postoperative axial neck pain.

Influence of spinal cord compression and traumatic force on the severity of cervical spinal cord injury associated with ossification of the posterior longitudinal ligament.

STUDY DESIGN: Retrospective review. OBJECTIVE: To evaluate the influence of static compression factors and dynamic factors based on the various degrees of traumatic force on the cervical spinal cord injury (SCI) in patients with ossification of the posterior longitudinal ligament. SUMMARY OF BACKGROUND DATA: Spinal cord disorder occurs as a result of various factors, including static factors and traumatic force. Discussions about the severity of paralysis resulting from SCI must therefore focus on dynamic factors based on the traumatic force as well as on static compression factors. However, the past reports did not describe the influence of traumatic force in detail. METHODS: Fifty patients presenting with cervical SCI associated with ossification of the posterior longitudinal ligament were included in this study. The American Spinal Injury Association motor score 3 days after injury, the degree of the traumatic force, and the spinal cord compression rate were investigated, and the relationships among these factors were investigated. RESULTS: Paralysis at the time of injury was not determined by static factors alone or by traumatic force alone. The severity of paralysis at the time of injury was determined on the basis of a combination of both the static factors and the degree of traumatic force. CONCLUSION: Both the degree of spinal cord compression and the degree of traumatic force were found to be important factors associated with the severity of cervical SCI in patients with ossification of the posterior longitudinal ligament. LEVEL OF EVIDENCE: 4.

Clinical relationship between cervical spinal canal stenosis and traumatic cervical spinal cord injury without major fracture or dislocation.

PURPOSE: The purpose of the study was to evaluate the clinical relationship between cervical spinal canal stenosis (CSCS) and incidence of traumatic cervical spinal cord injury (CSCI) without major fracture or dislocation, and to discuss the clinical management of traumatic CSCI. METHODS: Forty-seven patients with traumatic CSCI without major fracture or dislocation (30 out of 47 subjects; 63.83 %, had an injury at the C3-4 segment) and 607 healthy volunteers were measured the sagittal cerebrospinal fluid (CSF) column diameter at five pedicle and five intervertebral disc levels using T2-weighted midsagittal magnetic resonance imaging. We defined the sagittal CSF column diameter of less than 8 mm as CSCS based on the previous paper. We evaluated the relative and absolute risks for the incidence of traumatic CSCI related with CSCS. RESULTS: Using data from the Spinal Injury Network of Fukuoka, Japan, the relative risk for the incidence of traumatic CSCI at the C3-4 segment with CSCS was calculated as 124.5:1. Moreover, the absolute risk for the incidence of traumatic CSCI at the C3-4 segment with CSCS was calculated as 0.00017. CONCLUSIONS: In our results, the relative risk for the incidence of traumatic CSCI with CSCS was 124.5 times higher than that for the incidence without CSCS. However, only 0.017 % of subjects with CSCS may be able to avoid developing traumatic CSCI if they undergo decompression surgery before trauma. Our results suggest that prophylactic surgical management for CSCS might not significantly affect the incidence of traumatic CSCI.

Analysis of the risk factors for tracheostomy in traumatic cervical spinal cord injury.

STUDY DESIGN: A retrospective, consecutive case series. OBJECTIVE: To determine the risk factors that have a statistically significant association with the need of tracheostomy in patients with cervical spinal cord injury (CSCI) at the acute stage. SUMMARY OF BACKGROUND DATA: Respiratory complications remain a major cause of further morbidity and mortality in patients with CSCI. Although several risk factors for tracheostomy have been postulated in these patients, no definitive factors have yet been established according to a multivariate analysis. The use of vital capacity was considered as a single global measure of respiratory function in patients with spinal cord injury, but there are very few studies in which the forced vital capacity was investigated as a risk factor for tracheostomy. METHODS: This study that reviewed the clinical data of 319 patients with CSCI, who were evaluated for their neurological impairment within 2 days after injury, was performed. We analyzed the factors postulated to increase the risk for tracheostomy, including patient's age, neurological impairment scale grade and level, smoking history, pre-existing medical comorbidities, respiratory diseases, Injury Severity Score, forced vital capacity, and percentage of vital capacity to the predicted value (%VC), using a multiple logistic regression model and classification and regression tree analysis. RESULTS: Of 319 patients, 32 patients received tracheostomy (10.03%). The factors identified using a multiple logistic regression model were high age (69 years of age or older), severe neurological impairment scale, low forced vital capacity (≤ 500 mL), and low percentage of vital capacity to the predicted value (<16.3%). The decision tree analysis demonstrated that forced vital capacity, the severe neurological impairment scale, and high patient age were predictive of need for tracheostomy on 94.4% occasions. CONCLUSION: The measurement of forced vital capacity is indispensable to predict the need for tracheostomy in patients with CSCI at the acute stage.

Soft-tissue damage and segmental instability in adult patients with cervical spinal cord injury without major bone injury.

STUDY DESIGN: A retrospective imaging and clinical study. OBJECTIVE: To evaluate the extraneural soft-tissue damage and its clinical relevance in patients with traumatic cervical spinal cord injury (SCI) without major bone injury. SUMMARY OF BACKGROUND DATA: To date, various kinds of cervical discoligamentous injuries have been demonstrated on magnetic resonance images in patients with SCI without bony injury. However, it has not been clear whether these magnetic resonance imaging abnormalities are actually related to spinal segmental instability and the patients' neurological status. METHODS: Eighty-eight adult patients with acute traumatic cervical SCI without major bone injury were examined by flexion-extension lateral radiographs and magnetic resonance images within 2 days after trauma. We excluded patients with flexion recoil injury; therefore, most of the patients included were considered to have sustained a hyperextension injury. Instability of the injured cervical segment was defined when there was more than 3.5-mm posterior translation and/or more than a 11° difference in the intervertebral angle between the site of interest and adjacent segments. The neurological status was evaluated according to the American Spinal Injury Association motor score. RESULTS: On magnetic resonance images, the damage to the anterior longitudinal ligament and intervertebral disc were apparent in 44 and 37 patients, respectively. Various degrees of prevertebral fluid collection (prevertebral hyperintensity) were demonstrated in 76 patients. These magnetic resonance imaging abnormalities were significantly associated with initial cervical segmental instability as judged by flexion-extension radiographs. Interestingly, the American Spinal Injury Association motor score had a significant association with either magnetic resonance imaging abnormalities or segmental instability but not with the cervical canal diameter. CONCLUSION: A considerable proportion of the patients with traumatic cervical SCI without major bone injury were shown to have various types of soft-tissue damage associated with cervical segmental instability at the early stages of the injury. The severity of paralysis greatly depended on these discoligamentous injuries.

Spinous process-splitting open pedicle screw fusion provides favorable results in patients with low back discomfort and pain compared to conventional open pedicle screw fixation over 1 year after surgery.

INTRODUCTION: The conventional open pedicle screw fusion (PSF) requires an extensive detachment of the paraspinal muscle from the posterior aspect of the lumbar spine, which can cause muscle injury and subsequently lead to "approach-related morbidity". The spinous process-splitting (SPS) approach for decompression, unilateral laminotomy for bilateral decompression, and the Wiltse approach for pedicle screw insertion are considered to be less invasive to the paraspinal musculature. We investigated whether SPS open PSF combined with the abovementioned techniques attenuates the paraspinal muscle damage and yields favorable clinical results, including alleviation in the low back discomfort, in comparison to the conventional open PSF. METHODS: We studied 53 patients who underwent single-level PSF for the treatment of degenerative spondylolisthesis (27 patients underwent SPS open PSF and the other 26 underwent the conventional open PSF). The clinical outcomes were assessed using the Japanese Orthopedic Association (JOA) score, the Roland-Morris disability questionnaire (RDQ), and the visual analog scale (VAS) for low back pain and low back discomfort (heavy feeling or stiffness). Postoperative multifidus (MF) atrophy was evaluated using MRI. Follow-up examinations were performed at 1 and 3 years after the surgery. RESULTS: Although there was no significant difference in the JOA and RDQ score between the two groups, the VAS score for low back pain and discomfort after the surgery were significantly lower in the SPS open PSF group than in the conventional open PSF group. The extent of MF atrophy after SPS open PSF was reduced more significantly than after the conventional open PSF during the follow-up. The MF atrophy ratio was found to correlate with low back discomfort at the 1-year follow-up examination. CONCLUSION: In conclusion, SPS open PSF was less damaging to the paraspinal muscle than the conventional open PSF and had a significant clinical effect, reducing low back discomfort over 1 year after the surgery.

Evaluating (13)C enrichment data of free amino acids for precise metabolic flux analysis.

Metabolic flux analysis using (13)C enrichment data of intracellular free amino acids (FAAs) can improve the time resolution of flux estimation compared to analysis of proteinogenic amino acid data owing to the faster turnover times of FAAs. The nature of the (13)C enrichment dynamics of FAAs remains obscure, however, especially with regard to its dependence on culture conditions, even though an understanding of dynamic behavior is important for precise metabolic flux estimation. In this study, we analyzed the (13)C enrichment dynamics of free and proteinogenic amino acids in a series of continuous culture experiments with Escherichia coli. The results indicated that the effect of protein degradation on the (13)C enrichment of FAAs was negligible under cellular growth conditions. Furthermore, they showed that the time scale necessary for (13)C enrichment dynamics of FAAs to reach a steady state depends on culture conditions such as oxygen uptake rate, which was likely due to different pool sizes of intracellular metabolites. The results demonstrate the importance of analyzing (13)C enrichment dynamics for the precise estimation of metabolic fluxes using FAA data.

Analysis of the risk factors for severity of neurologic status in 216 patients with thoracolumbar and lumbar burst fractures.

STUDY DESIGN: A retrospective, consecutive case series. OBJECTIVE: To determine the risk factors that have a significant correlation with the severity of neurologic impairment in thoracolumbar and lumbar burst fractures. SUMMARY OF BACKGROUND DATA: The correlation between spinal canal stenosis due to bony fragments and the severity of neurologic deficits in thoracolumbar and lumbar burst fractures remains controversial. Moreover, there have so far been no reports in the literature in which the risk factors (spinal canal stenosis and the disruption of posterior ligamentous complex) causing a severe neurologic deficit were analyzed using a multiple logistic regression model. METHODS: A review of the clinical data (neurologic impairments on admission and a finding of posterior ligamentous complex disruption at the time of operation), axial computed tomography, and plain lateral radiography of 216 patients in thoracolumbar (T11-L1) and lumbar (L2-L5) burst fractures was performed. The factors related to neurologic impairments were analyzed using a multiple logistic regression model. RESULTS: In all cases, both the spinal canal stenosis (P < 0.01) and disruption of posterior ligamentous complex (P < 0.01) were significant risk factors. Interestingly, these two risk factors varied according to the injury levels: at thoracic level, the spinal canal stenosis (P < 0.01); at the first lumbar spine, the disruption of the posterior ligamentous complex (P < 0.01); and at the lumbar spine below L2, both of the spinal canal stenosis (P < 0.01) and the disruption of posterior ligamentous complex (P < 0.05) were significant risk factors, respectively. CONCLUSION: In the patients with thoracolumbar and lumbar burst fractures, the significance of the two important risk factors related to clinical results, namely, the stenosis ratio of spinal canal and the disruption of posterior ligamentous complex, were found to vary depending on the level of injury.

Predominant antitumor effects by fully human anti-TRAIL-receptor 2 (DR5) monoclonal antibodies in human glioma cells in vitro and in vivo.

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL/Apo2 L) preferentially induces apoptosis in human tumor cells through its cognate death receptors DR4 or DR5, thereby being investigated as a potential agent for cancer therapy. Here, we applied fully human anti-human TRAIL receptor monoclonal antibodies (mAbs) to specifically target one of death receptors for TRAIL in human glioma cells, which could also reduce potential TRAIL-induced toxicity in humans. Twelve human glioma cell lines treated with several fully human anti-human TRAIL receptor mAbs were sensitive to only anti-DR5 mAbs, whereas they were totally insensitive to anti-DR4 mAb. Treatment with anti-DR5 mAbs exerted rapid cytotoxicity and lead to apoptosis induction. The cellular sensitivity was closely associated with cell-surface expression of DR5. Expression of c-FLIP(L), Akt, and Cyclin D1 significantly correlated with sensitivity to anti-DR5 mAbs. Primary cultures of glioma cells were also relatively resistant to anti-DR5 mAbs, exhibiting both lower DR5 and higher c-FLIP(L) expression. Downregulation of c-FLIP(L) expression resulted in the sensitization of human glioma cells to anti-DR5 mAbs, whereas overexpression of c-FLIP(L) conferred resistance to anti-DR5 mAb. Treatment of tumor-burden nude mice with the direct agonist anti-DR5 mAb KMTR2 significantly suppressed growth of subcutaneous glioma xenografts leading to complete regression. Similarly, treatment of nude mice bearing intracerebral glioma xenografts with KMTR2 significantly elongated lifespan without tumor recurrence. These results suggest that DR5 is the predominant TRAIL receptor mediating apoptotic signals in human glioma cells, and sensitivity to anti-DR5 mAbs was determined at least in part by the expression level of c-FLIP(L) and Akt. Specific targeting of death receptor pathway through DR5 using fully human mAbs might provide a novel therapeutic strategy for intractable malignant gliomas.

Engineering of sugar metabolism of Corynebacterium glutamicum for production of amino acid L-alanine under oxygen deprivation.

Corynebacterium glutamicum was genetically engineered to produce L-alanine from sugar under oxygen deprivation. The genes associated with production of organic acids in C. glutamicum were inactivated and the alanine dehydrogenase gene (alaD) from Lysinibacillus sphaericus was overexpressed to direct carbon flux from organic acids to alanine. Although the alaD-expressing strain produced alanine from glucose under oxygen deprivation, its productivity was relatively low due to retarded glucose consumption. Homologous overexpression of the gapA gene encoding glyceraldehyde 3-phosphate dehydrogenase (GAPDH) in the alaD-expressing strain stimulated glucose consumption and consequently improved alanine productivity. In contrast gapA overexpression did not affect glucose consumption under aerobic conditions, indicating that oxygen deprivation engendered inefficient regeneration of NAD+ resulting in impaired GAPDH activity and reduced glucose consumption in the alanine-producing strains. Inactivation of the alanine racemase gene allowed production of L-alanine with optical purity greater than 99.5%. The resulting strain produced 98 g l(-1) of L-alanine after 32 h in mineral salts medium. Our results show promise for amino acid production under oxygen deprivation.

Efficient antibody production upon suppression of O mannosylation in the yeast Ogataea minuta.

When antibodies were expressed in the methylotrophic yeast Ogataea minuta, we found that abnormal O mannosylation occurred in the secreted antibody. Yeast-specific O mannosylation is initiated by the addition of mannose at serine (Ser) or threonine (Thr) residues in the endoplasmic reticulum via protein O mannosyltransferase (Pmt) activity. To suppress the addition of O-linked sugar chains on antibodies, we examined the possibility of inhibiting Pmt activity by the addition of a Pmt inhibitor during cultivation. The Pmt inhibitor was found to partially suppress the O mannosylation on the antibodies. Surprisingly, the suppression of O mannosylation was associated with an increased amount of assembled antibody (H2L2) and enhanced the antigen-binding activity of the secreted antibody. In this study, we demonstrated the expression of human antibody in O. minuta and elucidated the relationship between O mannosylation and antibody production in yeast.

Antibody expression in protease-deficient strains of the methylotrophic yeast Ogataea minuta.

When human antibody genes were expressed in the methylotrophic yeast Ogataea minuta, the secreted antibody became partially degraded. To suppress the degradation, a vacuolar protease-deficient strain was constructed and its antibody production was evaluated. Although antibody productivity was improved in the vacuolar protease-deficient strain, the secreted antibody still became partially degraded. Peptide sequencing revealed that the cleavage occurred in the CH1 region of the heavy chain, implying that the cleavage was caused by an aspartic protease, Yps1p. To inhibit this cleavage, Yps1p-deficient strains were constructed and their antibody production was evaluated. As a result, the partial degradation of the antibody was suppressed in the O. minuta multiple-protease-deficient strains.