89 research outputs found

    A Tissue Displacement-based Contusive Spinal Cord Injury Model in Mice

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    Producing a consistent and reproducible contusive spinal cord injury (SCI) is critical to minimizing behavioral and histological variabilities between experimental animals. Several contusive SCI models have been developed to produce injuries using different mechanisms. The severity of the SCI is based on the height that a given weight is dropped, the injury force, or the spinal cord displacement. In the current study, we introduce a novel mouse contusive SCI device, the Louisville Injury System Apparatus (LISA) impactor, which can create a displacement-based SCI with high injury velocity and accuracy. This system utilizes laser distance sensors combined with advanced software to produce graded and highly-reproducible injuries. We performed a contusive SCI at the 10th thoracic vertebral (T10) level in mice to demonstrate the step-by-step procedure. The model can also be applied to the cervical and lumbar spinal levels

    A Novel Vertebral Stabilization Method for Producing Contusive Spinal Cord Injury

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    Clinically-relevant animal cervical spinal cord injury (SCI) models are essential for developing and testing potential therapies; however, producing reliable cervical SCI is difficult due to lack of satisfactory methods of vertebral stabilization. The conventional method to stabilize the spine is to suspend the rostral and caudal cervical spine via clamps attached to cervical spinous processes. However, this method of stabilization fails to prevent tissue yielding during the contusion as the cervical spinal processes are too short to be effectively secured by the clamps (Figure 1). Here we introduce a new method to completely stabilize the cervical vertebra at the same level of the impact injury. This method effectively minimizes movement of the spinal column at the site of impact, which greatly improves the production of consistent SCIs. We provide visual description of the equipment (Figure 2-4), methods, and a step-by-step protocol for the stabilization of the cervical 5 vertebra (C5) of adult rats, to perform laminectomy (Figure 5) and produce a contusive SCI thereafter. Although we only demonstrate a cervical hemi-contusion using the NYU/MASCIS impactor device, this vertebral stabilization technique can be applied to other regions of the spinal cord, or be adapted to other SCI devices. Improving spinal cord exposure and fixation through vertebral stabilization may be valuable for producing consistent and reliable injuries to the spinal cord. This vertebral stabilization method can also be used for stereotactic injections of cells and tracers, and for imaging using two-photon microscopy in various neurobiological studies

    Testosterone Levels in Men with Chronic Migraine

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    Chronic migraine is a frequent and debilitating condition affecting 14% of the general population. This prospective observational pilot study investigated whether men with chronic migraine have lower than expected total serum testosterone levels. We identified 14 men ages 26-51 at our Institution who fulfilled the ICHD-3b criteria for chronic migraine and obtained serum total testosterone levels. The mean total testosterone level in our 14 patients was 322 ng/dL (range: 120-542 ng/dL) which is in the lower 5% of the reference range for our laboratory (300-1080 ng/dL). Men with chronic migraine had lower total testosterone levels compared to published agematched normative median values by a median difference of 62 ng/dL (P=0.0494). This finding suggests that hypothalamic regulation is altered in patients with chronic migraine. Further studies are warranted to determine whether testosterone supplementation in men with chronic migraine reduces the number of headaches or the associated symptoms of hypogonadism

    A Young Stellar Cluster in the Nucleus of NGC 4449

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    We have obtained 1-2 A resolution optical Echellette spectra of the nuclear star cluster in the nearby starburst galaxy NGC 4449. The light is clearly dominated by a very young (6-10 Myr) population of stars. For our age dating, we have used recent population synthesis models to interpret the observed equivalent width of stellar absorption features such as the HI Balmer series and the CaII triplet around 8500 A. We also compare the observed spectrum of the nuclear cluster to synthesized spectra of simple stellar populations of varying ages. All these approaches yield a consistent cluster age. Metallicity estimates based on the relative intensities of various ionization lines yield no evidence for significant enrichment in the center of this low mass galaxy: the metallicity of the nuclear cluster is about one fourth of the solar value, in agreement with independent estimates for the disk material of NGC 4449.Comment: 24 pages (incl. 7 figures), accepted by AJ, March 2001 issue revised version with minor changes and additions, one additional figur

    An In Vivo Duo-color Method for Imaging Vascular Dynamics Following Contusive Spinal Cord Injury

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    Spinal cord injury (SCI) causes significant vascular disruption at the site of injury. Vascular pathology occurs immediately after SCI and continues throughout the acute injury phase. In fact, endothelial cells appear to be the first to die after a contusive SCI. The early vascular events, including increased permeability of the blood-spinal cord barrier (BSCB), induce vasogenic edema and contribute to detrimental secondary injury events caused by complex injury mechanisms. Targeting the vascular disruption, therefore, could be a key strategy to reduce secondary injury cascades that contribute to histological and functional impairments after SCI. Previous studies were mostly performed on postmortem samples and were unable to capture the dynamic changes of the vascular network. In this study, we have developed an in vivo duo-color two-photon imaging method to monitor acute vascular dynamic changes following contusive SCI. This approach allows detecting blood flow, vessel diameter, and other vascular pathologies at various sites of the same rat pre- and post-injury. Overall, this method provides an excellent venue for investigating vascular dynamics

    Dexamethasone Administration During Definitive Radiation and Temozolomide Renders a Poor Prognosis in a Retrospective Analysis of Newly Diagnosed Glioblastoma Patients

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    BACKGROUND: Dexamethasone (DXM) is commonly used in the management of cerebral edema in patients diagnosed with glioblastoma multiforme (GBM). Bevacizumab (BEV) is FDA-approved for the progression or recurrence of GBM but has not been shown to improve survival when given for newly diagnosed patients concurrently with radiation (RT) and temozolomide (TMZ). Both DXM and BEV reduce cerebral edema, however, DXM has been shown to induce cytokine cascades which could interfere with cytotoxic therapy. We investigated whether DXM would reduce survival of GBM patients in the setting of concurrent TMZ and BEV administration. METHODS: We reviewed the treatment of all 73 patients with GBM who received definitive therapy at our institution from 2005 to 2013 with RT (60 Gy) delivered with concurrent daily TMZ (75 mg/m2). Of these, 34 patients also were treated with concurrent BEV (10 mg/kg every two weeks). Patients received adjuvant therapy (TMZ or TMZ/Bev) until either progression, discontinuation due to toxicity, or 12 months after radiation completion. All patients who had GBM progression with TMZ were offered BEV for salvage therapy, with 19 (56 %) receiving BEV. RESULTS: With a median follow-up of 15.6 months, 67 (91.8 %) patients were deceased. The OS for the entire cohort was 15.9 months, while the PFS was 7.7 months. The extent of resection was a prognostic indicator for OS (p  = .0044). The median survival following gross tumor resection (GTR) was 22.5 months, subtotal resection (STR) was 14.9 months, and biopsy was 12.1 months. The addition of BEV to TMZ with RT was borderline significantly associated with increased PFS (9.4 vs. 5.1 months, p = 0.0574) although was not significantly associated with OS (18.1 vs. 15.3 months respectively, p  = 0.3064). In patients receiving TMZ, DXM use concurrent with RT was a poor prognostic indicator of both OS (12.7 vs. 22.6 months, p = 0.003) and PFS (3.6 vs. 8.4 months, p p = 0.4818). On multivariable analysis, DXM use predicted an unfavorable OS hazard ratio (HR) = 1.72, p = 0.045). CONCLUSIONS: Our results with TMZ, BEV, and RT are similar to previous studies in terms of PFS and OS. DXM use during RT with concurrent TMZ correlated with reduced OS and PFS unless BEV was administered

    Assessment of infant feeding styles among low-income African-American mothers: Comparing reported and observed behaviors

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    This study’s goal was to provide a detailed description of feeding styles adopted by a sample of African-American women in feeding their infants in North Carolina, and to examine the correspondence between reported and observed feeding styles. Cross-sectional semi-structured interview and videotaped data were gathered in the homes of 20 participating low-income mothers of infants aged 3-20 months. Feeding styles were characterized through a tailored coding scheme (the Infant Feeding Styles Video Coding Scheme, IFSVCS) applied to both interview and video-taped data. We found that the most frequent feeding styles identified for both interviews and videotaped observations was restrictive, but that mothers were roughly equally divided among predominantly controlling (pressuring or restrictive) and less controlling (laissez-faire or indulgent) styles across methods. However, for over 2/3 of the sample, there was a lack of correspondence between interview and video-taped feeding styles. This unique characterization and comparison of observed and reported infant feeding styles provides additional insights into parental feeding approaches among mothers of infants at high risk of obesity, and highlights the need for further study of feeding style assessment and potential impact on infant weight outcomes

    Frameless Image-Guided Radiosurgery for Trigeminal Neuralgia

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    Background: Frameless image-guided radiosurgery (IGRS) is a safe and effective noninvasive treatment for trigeminal neuralgia (TN). This study evaluates the use of frameless IGRS to treat patients with refractory TN. Methods: We reviewed the records of 20 patients diagnosed with TN who underwent frameless IGRS treatments between March 2012 and December 2013. Facial pain was graded using the Barrow Neurological Institute (BNI) scoring system. The initial setup uncertainty from simulation to treatment and the patient intrafraction uncertainty were measured. The median follow-up was 32 months. Results: All patients\u27 pain was BNI Grade IV or V before the frameless IGRS treatment. The mean intrafraction shift was 0.43 mm (0.28-0.76 mm), and the maximum intrafraction shift was 0.95 mm (0.53-1.99 mm). At last follow-up, 8 (40%) patients no longer required medications (BNI 1 or 2), 11 (55%) patients were pain free but required medication (BNI 3), and 1 (5%) patient had no pain relief (BNI 5). Patients who did not have prior surgery had a higher odds ratio for pain relief compared to patients who had prior surgery (14.9, P = 0.0408). Conclusions: Frameless IGRS provides comparable dosimetric and clinical outcomes to frame-based SRS in a noninvasive fashion for patients with medically refractory TN

    Single Low-Dose Targeted Bevacizumab Infusion in Adult Patients with Steroid-Refractory Radiation Necrosis of the Brain: A Phase II Open-Label Prospective Clinical Trial

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    OBJECTIVE There is an unmet need for safe and rapidly effective therapies for refractory brain radiation necrosis (RN). The aim of this prospective single-arm phase II trial was to evaluate the safety and efficacy of a single low-dose targeted bevacizumab infusion after blood-brain barrier disruption (BBBD) in adult patients with steroid-refractory brain RN. METHODS Ten adults with steroid-refractory, imaging-confirmed brain RN were enrolled between November 2016 and January 2018 and followed for 12 months after treatment. Bevacizumab 2.5 mg/kg was administered as a one-time targeted intra-arterial infusion immediately after BBBD. Primary outcomes included safety and \u3e 25% decrease in lesion volume. Images were analyzed by a board-certified neuroradiologist blinded to pretrial diagnosis and treatment status. Secondary outcomes included changes in headache, steroid use, and functional status and absence of neurocognitive sequelae. Comparisons were analyzed using the Fisher exact test, Mann-Whitney U-test, linear mixed models, Wilcoxon signed-rank test, and repeated-measures 1-way ANOVA. RESULTS Ten adults (mean ± SD [range] age 35 ± 15 [22-62] years) participated in this study. No patients died or exhibited serious adverse effects of systemic bevacizumab. At 3 months, 80% (95% CI 44%-98%) and 90% (95% CI 56%-100%) of patients demonstrated \u3e 25% decrease in RN and vasogenic edema volume, respectively. At 12 months, RN volume decreased by 74% (median [range] 76% [53%-96%], p = 0.012), edema volume decreased by 50% (median [range] 70% [-11% to 83%], p = 0.086), and headache decreased by 84% (median [range] 92% [58%-100%], p = 0.022) among the 8 patients without RN recurrence. Only 1 (10%) patient was steroid dependent at the end of the trial. Scores on 12 of 16 (75%) neurocognitive indices increased, thereby supporting a pattern of cerebral white matter recovery. Two (20%) patients exhibited RN recurrence that required further treatment at 10 and 11 months, respectively, after bevacizumab infusion. CONCLUSIONS For the first time, to the authors\u27 knowledge, the authors demonstrated that a single low-dose targeted bevacizumab infusion resulted in durable clinical and imaging improvements in 80% of patients at 12 months after treatment without adverse events attributed to bevacizumab alone. These findings highlight that targeted bevacizumab may be an efficient one-time treatment for adults with brain RN. Further confirmation with a randomized controlled trial is needed to compare the intra-arterial approach with the conventional multicycle intravenous regimen

    Photometric and Spectroscopic Observations of SN 1990E in NGC 1035: Observational Constraints for Models of Type II Supernovae

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    We present 126 photometric and 30 spectral observation of SN 1990E spanning from 12 days before B maximum to 600 days past discovery. These observations show that SN 1990E was of type II-P, displaying hydrogen in its spectrum, and the characteristic plateau in its light curve. SN 1990E is one of the few SNe II which has been well observed before maximum light, and we present evidence that this SN was discovered very soon after its explosion. In the earliest spectra we identify, for the first time, several N II lines. We present a new technique for measuring extinction to SNe II based on the evolution of absorption lines, and use this method to estimate the extinction to SN 1990E, Av=1.5+/-0.3 mag. From our photometric data we have constructed a bolometric light curve for SN 1990E and show that, even at the earliest times, the bolometric luminosity was falling rapidly. We use the late-time bolometric light curve to show that SN 1990E trapped a majority of the gamma rays produced by the radioactive decay of 56Co, and estimate that SN 1990E ejected 0.073 Mo of 56Ni, an amount virtually identical to that of SN 1987A. [excerpt
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